Industrial Products – Aaron Socha, Seema Singh, Blake A. Simmons, Maxime Bergeron, University of California, National Technology and Engineering Solutions of Sandia LLC
Abstract for “Synthesis and use of lignin-derived compounds to synthesize novel ionic liquids”
“Methods, compositions, and methods are provided to synthesize ionic liquids out of lignin. There are methods and compositions for treating lignin using ionic liquids.
Background for “Synthesis and use of lignin-derived compounds to synthesize novel ionic liquids”
“Biorefineries are able to process biological materials, such as lignocellulosic biomass, or any components thereof, in order to extract and create valuable materials. Biorefineries must be able to utilize lignin efficiently. This is an important concept that will improve their economic viability. Lignin can also be extracted from lignocellulosic biomass to make pulp and paper. The pulp and paper industry produces lignins such as kraft lignin (produced via the Kraft process), lignosulfonates (produced, e.g. Alkali lignin is produced by the sulfite-pulping process. The soda process black liquor can be treated with acid and low-sulfonate alkali.lignin. These lignins can be extracted, purified and/or derivatized in the same way as lignocellulosic biomass.
“Lignin from pulp and paper producers and biorefineries is often combusted to produce heat, steam, and electricity. This lignin use has a low economic value compared to other sources such as natural gas, steam, and electricity. Newer, more efficient plants can produce more of lignin than is required for heat, steam and electricity generation. New technologies are required to transform polymeric lignin from biorefineries and pulp or paper producers into higher-value products.
“Lignocellulosic biofuel is made from agricultural wastes, forest residuals, and other dedicated energy crops. It has taken a lot of effort to create methods for producing useful compounds from lignocellulosic biomacromolecules. The recalcitrant nature lignocellulosic biomacromolecules, which are resistant to the breakdown and extraction of useful compounds, is one of the biggest obstacles to the technology’s economic viability. This resistance requires the use of treatment methods to increase the accessibility and depolymerization the lignocellulosic biofuel’s lignin and carbohydrate components. The majority of treatment methods use thermochemical processes, which combine high temperatures and pressures with dilute acids or alkalis to open up the biomass’ structure. These processes require specialized equipment and high energy inputs.
“Ionic liquids (ILs), which are innovative fluids for chemical processing, have recently been developed. Because of their low volatility and potential for recyclability, they are environmentally friendly solvents. ILs have been proven to be a promising technology for treating biomass. They can dissolve crystalline cellulose in biomass under mild conditions.
Although lignocellulosic biomass can be treated with ionic fluids with great success, the process can be time- and energy-intensive. The art requires a process that can produce ionic liquids at a lower price and supplies high-quality, renewable lignin-derived chemicals to improve process economics. These and other requirements are met by the present invention.
“In some embodiments, this invention provides a method for creating an ionic fluid. It involves: Contacting a starting material consisting of lignin with depolymerization agents to depolymerize the plant; contacting the mixture aldehyde-containing compounds with an aldehyde under conditions that convert the mixture to an aldehyde-containing compound to an amine mixture; and finally, contacting the mixture amine-containing compounds with an acid in conditions that form an ammonium salt.
“In some embodiments, this invention provides an ionic fluid. It is prepared by contacting a starting matter comprising lignin with depolymerization agents to depolymerize lignin, and then contacting the mixture aldehyde-containing compounds with an aldehyde under conditions that convert the mixture into a mixture containing amines. Finally, contacting the mixture amine-containing compounds with a mineral acids under conditions that allow for the formation of an ammonium salt.
“In certain embodiments, the invention provides an ionic fluid consisting at least one compound from the following formula:
“wherein each R group of nitrogen is H,CH3, or CH2CH3 and at least two R groups are independently selected from CH3 or CH2CH3 or R?, R?? independent selection from H, OH and OCH3; R4 from H, OH and CH2OH; and X an acid anion.”
“In some instances, the present invention provides a mixture consisting at least two of these ionic liquids. The present invention can provide a mixture that contains at least three of these ionic liquids in some cases. The present invention can provide a mixture that contains at least four of these ionic liquids in some instances. The present invention can provide a mixture that contains at least five of these ionic liquids in some instances. The present invention can provide a mixture that contains at least six of these ionic liquids in some instances. The present invention can provide a mixture that contains at least seven of these ionic liquids in some instances. The present invention can provide a mixture that contains at least eight of these ionic liquids in some instances. In other instances, the present invention allows for a mixture that contains at least nine of these ionic liquids. The present invention can provide a mixture containing at least 10% w/v at least one of the above ionic liquids.
“I. Overview”
“Lignin is the second-most abundant biopolymer on Earth. It is a heterogeneous, heterogeneous macromolecule that consists of three phenylpropane unit (a.k.a. monlignols), p-coumaryl, coniferyl and sinapyl alcohol. (FIG. 1) The monolignol content of lignin is affected by its origin (hardwood, grass or softwood) and the extraction method from biomass.
“Lignin polymerization can be done by a variety of methods, including pyrolysis (e.g. gasification, thermolysis and hydrogenolysis), chemical oxidation, combustion, and ionic liquid-mediated. Different product combinations can be obtained depending on the type of starting material (e.g. hardwood, softwood or grass) as well as the extraction and depolymerization processes.
“Depolymerization may produce aromatic low molecular mass (e.g. monomer, dimer or trimer). Products containing alcohol, aldehyde, and carboxylic acids functional groups. These functional groups may be used as chemical “handles”. These functional groups can be used to convert lignin-derived monmers into ionic fluids. The present invention can provide ionic liquids that are low in molecular weight monomers, dimers, trimers, and so forth. products of lignin polymerization. For example, low molecular weight (e.g., monomer, dimer, trimer, etc.) The present invention allows for the conversion of products of lignin that contain aldehydes and carboxylic acid, as well as alcohols, into ionic fluids. One or more low molecular weight aldehydes and carboxylic acid, as well as alcohols, can be aromatic. Sometimes, the ionic fluids are made from low-cost starting materials (e.g., lignin from a biorefiner or a pulp and paper manufacturer). The present invention allows for the production of ionic liquids at lower costs. The ionic liquids created by the methods described herein may be novel in some instances. Some mixtures of ionic fluids created by the methods described herein may be novel.
The invention’s ionic liquids can be used in any method that is known or envisaged to use ionic liquids. The invention’s ionic liquids can be used to process biomass as a component in a battery electrolyte or as dispersants in the manufacturing of pharmaceuticals, commodity and fine chemicals as well as as a pharmaceutical agent. The invention’s ionic liquids can be made from lignin. They can then be used to extract, dissolve and/or depolymerize the lignin during concurrent or subsequent pretreatment steps. The invention includes a closed loop process to generate ionic fluids from biomass during treatment of additional biomass.
“II. Definitions”
“?Ionic liquid? “?Ionic liquid?” refers to salts which are liquids and not crystals at room temperature. It is obvious to all who are skilled that many ionic liquids may be used in the invention. ChemFiles (2006) 9(9) teaches you about ionic liquids. These are available commercially from Sigma-Aldrich, Milwaukee, Wis. Such ionic liquids include, but are not limited to, 1-alkyl-3-alkylimidazolium alkanoate, 1-alkyl-3-alkylimidazolium alkylsulfate, 1-alkyl-3-alkylimidazolium methylsulfonate, 1-alkyl-3-alkylimidazolium hydrogensulfate, 1-alkyl-3-alkylimidazolium thiocyanate, and 1-alkyl-3-alkylimidazolium halide, wherein an ?alkyl? An alkyl group containing between 1 and 10 carbon atoms. An alkanoate is an alkanoate that contains between 1 and 10 carbon atoms. The alkyl can be an alkyl group that contains between 1 and 4 carbon atoms. The alkyl can be a methyl, ethyl, propyl, or butyl groups in some cases. The alkanoate can be defined as an alkanate that contains between 1 and 4 carbon atoms. The alkanoate can be an acetate in some cases. Sometimes, the halide can be chloride.
“Exemplary ionic liquids include, but are not limited to 1-ethyl-3-methylimidazolium acetate (EMIM acetate) or ([C2mim][OAc]), 1-ethyl-3-methylimidazolium chloride (EMIM Cl), 1-ethyl-3-methylimidazolium hydrogensulfate (EMIM HOSO3), 1-ethyl-3-methylimidazolium methylsulfate (EMIM MeOSO3), 1-ethyl-3-methylimidazolium ethylsulfate (EMIM EtOSO3), 1-ethyl-3-methylimidazolium methanesulfonate (EMIM MeSO3), 1-ethyl-3-methylimidazolium tetrachloroaluminate (EMIM AICl4), 1-ethyl-3-methylimidazolium thiocyanate (EMIM SCN), 1-butyl-3-methylimidazolium acetate (BMIM acetate), 1-butyl-3-methylimidazolium chloride (BMIM Cl), 1-butyl-3-methylimidazolium hydrogensulfate (BMIM HOSO3), 1-butyl-3-methylimidazolium methanesulfonate (BMIM MeSO3), 1-butyl-3-methylimidazolium methylsulfate (BMIM MeOSO3), 1-butyl-3-methylimidazolium tetrachloroaluminate (BMIM AICl4), 1-butyl-3-methylimidazolium thiocyanate (BMIM SCN), 1-ethyl-2,3-dimethylimidazolium ethylsulfate (EDIM EtOSO3), Tris(2-hydroxyethyl)methylammonium methylsulfate (MTEOA MeOSO3), 1-methylimidazolium chloride (MIM Cl), 1-methylimidazolium hydrogensulfate (MIM HOSO3), 1,2,4-trimethylpyrazolium methylsulfate, tributylmethylammonium methylsulfate, choline acetate, choline salicylate, and ionic liquids derived from low molecular weight lignin depolymerization products.”
“?Contacting? Contacting refers to bringing two or more distinct species into contact so that they can react. The reaction product can be made directly from the reaction between the added agents or as an intermediate from any of the additional reagents that can be used in the reaction mixture.
“?Lignin? “?Lignin?” is a phenylpropane-polymer of monolignol singlemers. It is found in the secondary cells of certain plants and some types of algae as an integral part. Three monolignol monomers are methoxylated in different degrees to lignin: p-coumaryl, coniferyl, and sinapyl. These lignols are incorporated into lignin in the form of the phenylpropanoidsp-hydroxyphenyl (H), guaiacyl (G), and syringyl (S), respectively. Gymnosperms have a blend of G and H in their lignin. Monocotyledonous, however, lignin contains a combination of both G and S. While many grasses are mainly G-rich, some palms are primarily S-rich. However, lignins do not contain large amounts of modified or incomplete monolignols. Other monomers are also present in non-woody plants.
“?Depolymerization agent? Any chemical or process that depolymerizes lignin. CuSO4/NaOH (Pearl 1942) and Pandey (2011) are examples of depolymerization agent. Ionic liquids can be used as depolymerization agents, such as alkyl-imidazolium and lignin-derived ionic fluids.
“?Aldehyde? Refers to any organic compound that contains the structure R?CHO. It consists of a carbonyl centre (a carbon double bonded with oxygen) and a R group, which can be any generic side chain.
“?Alkyl? “?Alkyl?” refers to an aliphatic radical that is either straight or branched and has the indicated number of carbon atoms. Any number of carbons can be included in alkyl, including C1-2,C1-3,C1-4,C1-6,C1-5,C1-7,C1-8,C1-9,C1-10,C2-3, C2-4 and C2-6, as well as C2-4,C2-5,C2-6, C3-4,C3-5,C3-6,C4-6,C4-6, and C5-6. C1-6 alkyl can include, but not be limited to: methyl, propyl and ethyl; isopropyl; butyl; isobutyl; sec.butyl; tert.butyl; pentyl. isopentyl. hexyl. Alkyl can also be used to refer to alkyl group with up to 20 carbon atoms. This includes, but is not limited to, heptyl and octyl as well as nonyl and decyl. You can substitute or unsubstitute alkyl groups.
“?Amine? “?Amine” refers to an N(R]2 group, where the R groups may be hydrogen, alkyl or alkenyl and alkynyl. You can have the same R group or you can have different ones. You can have primary or secondary amino groups (each one is hydrogen), or tertiary (each is another than hydrogen). What is a?tertiary amino? An amine with the general formula HNR3 where R is not H. Tertiary ammoniums can be protonated to form cations or non-ionized. A?quaternary amine? An ammonium cation according to the general formula NR4+.
“?Alkyl amine? An alkyl group, as defined in, that contains one or more amino acids. You can choose from primary, secondary, or tertiary amino groups. To make an amino-hydroxy group, the alkylamine can be substituted with a hydro group. The present invention uses alkylamines such as ethylamine, propylamine, isopropylamine, ethylene diamine, and ethanolamine. The amino group can either link the alkylamine to the point where it attaches with the rest, be in the omega position of an alkyl group or link at least two carbon atoms together from the alkyl groups. The present invention is applicable to other alkylamines.
“?Halide? “?Halide” refers to a fluoride or chloride, bromide or iodide ion, or compound.
“?Alkanoate? Refers to an alkane acids of the form R.COO?. The present invention includes alkan0ates that include, but not limited to, acetate.
“?Mineral acids? Inorganic acids are mineral acids. The present invention uses mineral acids such as sulfuric acid and hydrochloric Acid, nitric Acid, boric Acid, phosphoric Acid, hydrofluoric, hydrobromic, and perchloric acids.
“?Hydrogen donating agent? Agents that can participate in hydrogen transfer reactions, or are capable of reducing a reactant. The present invention includes tetralin and sodium formate as hydrogen donating agents. Pandey (2011) describes hydrogen donating agents. They also include active hydrogen donating solvents.
“?Catalyst? A substance that causes or speeds up a chemical reaction. Although catalysts are not usually consumed in chemical reactions, side reactions can inactivate, foul or consume catalysts. The present invention uses nickel, palladium and platinum catalysts. The present invention uses silica-alumina catalysts as well.
“?Oxidizing agent,? ?oxidant,? or ?oxidizer? The term?oxidizer? refers to any substance that removes electrons or removes hydrogen from a reactionant. The electron donating reaction reduces the oxidizing agent and acts as an electron acceptor. The present invention uses O2 gas, H2O2, Fenton?s reagent (H2O2 ferrous sulfate), Fenton’s reagent (H2O2 iron sulfate), and nitrobenzene as oxidizing agents.
“?Metal oxide? The oxide of any alkaline metal like Be, Mg or Ca, Sr, is called “Metal oxide”. Transition metals like Cr, Mn and Fe, Sc, Ti and V, Cr and Ni, Cu and Zn are also useful metals. Examples of metal oxides are MgO and Sb2O3. The present invention is useful for those with skill in the arts.
“?Metal organic framework?” “?Metal organic framework? The term?MOF? refers to compounds that contain metal ions or clusters and are coordinated to organic molecules in order to form porous structures. They are useful for catalysis as well as being lignin-depolymerization agents. The MOFs that are useful in the invention include MOFs made of copper or iron, as described in Masingale 2009”
“?Lignin-derived Ionic Liquid? Any ionic liquid that contains cations (e.g. “tertiary or quaternary aminos or anions” as used herein refers to any ionic liquid containing cations (e.g.
“?Reducing conditions? Reaction conditions are those that accelerate or cause the donation of electrons from a reactant. Reducing conditions useful in the present invention include reactions that contain Hz gas with a suitable catalyst, polymethylhydrosiloxane, sodium cyanoborohydride, sodium borohydride, sodium borohydride-trifluoroacetic acid, and sodium triacetoxyborohydride.”
“?Hydride donating reduction agent?” This refers to reducing agents which donate a hydroide to or reduce a reactant. Hydride donating reducing agents include Hz gas with a suitable catalyst, polymethylhydrosiloxane, sodium borohydride, sodium borohydride-trifluoroacetic acid, and sodium triacetoxyborohydride.”
“A ?salt metathesis reaction? A chemical reaction that involves the exchange of bonds between reacting chemical species. This results in the creation products with identical or similar bonding affiliations. This reaction is represented by the general scheme:\nA?B+C?D?A?D+C?B\nSalt metathesis is a common technique for exchanging counterions between the reacting species.”
“?Polar solvent? “Polar solvent” is a term that refers to solvents having a dielectric constant greater than 15 Protic and aprotic solvents are both polar solvents. ?Protic solvents? These solvents are those that dissolve anions by hydrogen bonding. They include isopropanol and formic acid as well as n-butanol and isopropanol. ?Aprotic solvents? These solvents are used to dissolve cations by interaction with their negative dipole. They include dimethylformamide and acetone as well as acetone, dimethylformamide, dimethyl sulfoxide and propylene carbonate.
“III. Ionic Liquids”
“In certain embodiments, the invention provides an ionic fluid containing at most one compound of this formula:
“Wherein each of R groups of nitrogen are independently selected between H, CH3, and CH2CH3; at least two R groups of nitrogen are independently selected among CH3 or CH2CH3:nR??, R??, or R?? independent selection from H, OH and OCH3;nR4 selected from H and OH; andnX an acid anion.
“In some embodiments the acid anion may be acetic acid (as HCO2?) ), formic acid, as HCO2? ), formic acid (as HCO2? ), citric acid, (e.g. as C3H5O (COO)3 3 ), sulfuric acid (as HSO4 ? ), hydrochloric (as Cl) ), hydrochloric acid (as Cl? ), boric acid, as H2BO3? ), phosphoric (as H2PO4? ), hydrofluoric Acid (as F) ), hydrobromic (as Br?) ), hydrobromic acid (as Br?
“In some embodiments, a mixture contains at least two of these ionic liquids. The present invention may provide a mixture that contains at least three of these ionic liquids in some instances. The present invention may provide a mixture that contains at least four of these ionic liquids in some embodiments. The present invention may provide a mixture that contains at least five of these ionic liquids in some embodiments. The present invention can provide a mixture that contains at least six of these ionic liquids in some embodiments. The present invention may provide a mixture that contains at least seven of these ionic liquids in some embodiments. The present invention may provide a mixture that contains at least eight of these ionic liquids in some embodiments. The present invention may provide a mixture that contains at least nine of these ionic liquids in some embodiments. The present invention can provide a mixture containing about 10% w/v at least one of these ionic liquids.
“In certain embodiments, the invention provides tertiary ionic liquids of ammonium tertiary ionic liquids. Tertiary ammonium isoonic liquids can also be made from lignin-derived materials. The tertiary ammonium ions can be made from low molecular-weight lignoaldehydes and lignoalcohols, for example. The present invention includes the following: Tertiary ammonium-ionic liquids
“where each R group is selected independently from the group consisting CH3 and CH2CH3;nR??, R? R???? and H, OH. R?? ), formic acid, as HCO2? ), formic acid (as HCO2? ), citric acid, (e.g. as C3H5O (COO)3 3 ), sulfuric acid (as HSO4 ? ), hydrochloric (as Cl) ), hydrochloric acid (as Cl? ), boric acid, as H2BO3? ), phosphoric (as H2PO4? ), hydrofluoric Acid (as F) ), hydrobromic (as Br?) ), hydrobromic acid (as Br?
“In some embodiments of the invention, ionic liquids are prepared by”
In some embodiments, the invention allows for multiple cations to be present in ionic liquids. A compound that contains one or several alcohols and one/more phenolic group, a complex containing one/more aldehydes and one/more aldehydes and one/more phenolic group, a composition containing one/more phenolic and/or multiple aldehydes or a compound with multiple aldehydes can be combined to create compounds with multiple secondary amines, multiple anilines or a combination or one/more amines and/or one/more analine These compounds can be converted to ionic fluids by salt formation, as described. In some embodiments, 5-hydroxymethylfurfural can be converted to an ionic liquid containing two cationic functional groups. For example, a compound containing multiple tertiary amines can be synthesized from 5-hydroxymethylfurfural via reductive amination of the aldehyde and direct amination of the alcohol by atom-economic hydrogen autotransfer. Salt formation can sometimes be used to synthesize the appropriate tertiary amine. One or more of the multiple Tertiary Ammonium Amines can be converted to Quaternary Ammonium Ions by, for example, reaction with dimethylcarbonate, or dimethylsulfate.
“Some embodiments of the invention provide quaternary ammonium-ionic liquids. Quaternary ammonium liquids can also be made from lignin-derived materials. The quaternary ammonium can be made from low molecular-weight lignoaldehydes or lignoalcohols, for example. In some instances, the tertiary aminos can be synthesized from low molecularweight lignoaldehydes or lignoalcohols and the quaternary ismonium ionic fluids are created therefrom. The following are examples of quaternary ammonium-ionic liquids according to the present invention:
“where each R group is selected independently from the group consisting CH3 and CH2CH3;nR??, R? R???? and H, OH. R?? ), formic acid, as HCO2? ), formic acid (as HCO2? ), citric acid, (e.g. as C3H5O (COO)3 3 ), sulfuric acid (as HSO4 ? ), hydrochloric (as Cl) ), hydrochloric acid (as Cl? ), boric acid, as H2BO3? ), phosphoric (as H2PO4? ), hydrofluoric Acid (as F) ), hydrobromic (as Br?) ), hydrobromic acid (as Br?
“Some embodiments of the invention provide ionic liquids derived by carboxylic acid products from lignin polymerization. The following are ionic liquids derived from carboxylic acid products of lignin depolymerization that are ionic according to the invention:
“Where each R?” “Where each R?
“The ionic liquids described in the present invention may be used as mixtures in some instances. Mixtures can contain one or several tertiary ionic fluids, one, or more, quaternary ionic liquors, one, or more, lignoacid-derived ionicliquids, or any combination thereof. The ionic fluids of the present invention may include a mixture containing ionic substances with different anions but the same cation. An example of this is an ionic liquid mix containing a Tertiary Ammonium (e.g. a cation form compound 1, 2, 3, 4, 5, 6 7, 8, 8 or 9 of FIG. 4. A tertiary amine of FIG. 7. Or a cation of the tertiaryamines of FIG. 8) or a quadernary ammonium (e.g. a quadernary ammonium of FIG. Complexed with a mixture (e.g., anions phosphoric acid or sulfuric acid) Another example is an ionic liquid mix containing a tertiary and quaternary ammonium. Complexed with a mixture lingoacid-derived anions (e.g. an anion of FIG. 9).”
“In other embodiments, the composition of ionic fluids can contain a mixture of different anion ionic liquids with different cations. Ionic liquids may contain an anion of sulfuric acid or phosphoric acid, and a mixture or cations (e.g. a mixture or one or more of the tertiary or quaternary monium ions). Alternately, the invention’s ionic liquid mixtures can contain a mixture of tertiary or quaternary ammoniumions (e.g. NHR3+ or NR4+) and a combination of lignoacid-derived anion (e.g. an anion of FIG. 9).”
“In other embodiments, the composition of the ionic fluids can contain a mixture of different anions and cations. An example of this is an ionic liquid mix that contains anions (e.g. anions of phosphoric acid and/or sulfuric acid derived anions) as well as a mixture tertiary or quaternary ammonium (e.g. two or more cation forms of compound 1, 2, 3, 4, 5, 6 7, 8, 8 or 9 of FIG. 4; A tertiary amine of FIG. 7; A cation form for a Tertiary Ammonium of FIG. 8; or, a quaternary amine of FIG. 10).”
“In certain embodiments, the thermal stability of the ionic liquids described in the present invention is high. The ionic liquids can have a high peak temperature for thermal decomposition. The Table 1 table shows examples of thermal decomposition temperatures in ionic liquids according to the invention.
“In certain embodiments, the ionic fluids of the present invention may dissolve lignin, as shown in FIG. 6. The ionic liquids can, in some instances, depolymerize the lignin. The ionic fluids of the invention can depolymerize and/or dissolve lignin in some instances. The time and energy required (e.g. heat, pressure, etc.), can determine efficiency. It is possible to depolymerize or dissolve lignin by calculating the time and energy required. The amount (e.g. weight or volume) required to dissolve a certain amount of lignin may also determine efficiency. The maximum amount of dissolved lignin found in any of the ionic liquids, or mixtures thereof, may also determine efficiency.
“IV. “IV. Methods of Preparing Ionic Fluids”
“In certain embodiments, the invention provides methods for generating ionic fluids from depolymerization products lignin. The following method is provided by the present invention in some embodiments:
“Lignin can be obtained by any method that is known to the art. For example, lignin can be extracted from biomass by a biorefinery, pulp or paper manufacturer or other means. Kraft lignin and lignosulfonate are examples of lignins. You can also make lignins from lignocellulosic biomasse, such as ionic liquid treatment.
“In some embodiments, this invention provides a method for extracting lignin lignocellulosic materials. This involves contacting the material with an Ionic Liquid prepared by contacting a material with a depolymerization agent. The mixture of aldehyde-containing compounds is converted to an aldehyde-containing compound mixture. A mixture of amine-containing compounds is then contacted with an acid under conditions that are suitable to form an Ammonium Salt. Sometimes, the method for extracting lignin involves depolymerizing the lignin.
There are two main categories of methods for extracting lignin from lignocellulosic biomacromolecules. Methods in which cellulose and/or hemicellulose are separated by solubilization leave lignin insoluble. The second group comprises methods that dissolve and remove lignin. This leaves cellulose and/or hemicellulose insoluble and then recovers lignin from the solution.
“Alternatively, the starting material for lignin may be provided as lignocellulosic biomasse. Pretreatment of the lignin and lignocellulosic biomass may be done using methods that are known to the art before or concurrently with lignin extract or depolymerization. You can pre-treat the lignin or lignocellulosic biomass by heating, burning, cracking, breaking, sawing, heat, steam explosion, ammonia fibre expansion, micro- or ultrasonic radiation, contact with a dilute, concentrated, or hot acid, CO2, hot or organic water, or any combination of these steps.
“Pretreatment conditions may also include the use of ionic fluids (e.g. Ionic liquids (e.g., those of the prior art) and dilute acids. Examples include 1, 2, 3, 5, 6, 7, 7, 8, 9, 12, 13, 14, 15, 16, 17, 18, 19, and about 20% hydrochloric acids.
Pretreatment can include the use a cosolvent. Water, an organic solvent or an additional ionic fluid can all be co-solvents. A co-solvent may be used in some cases to reduce the volume or concentration requirements of an ionic liquid. The ionic liquids described in the present invention can be used as co-solvents and/or in combination with other co-solvents to treat lignocellulosic biomass.
“A. Depolymerization”
“The present invention offers methods for contacting lignin using a depolymerization agents. Any chemical or process for depolymerizing polymeric, lignin to low molecular-weight compounds (e.g. monomers, dimers and trimers) is considered a depolymerization agent. Sometimes, the depolymerizing agents extract and depolymerize the lignin from a biomass. In some cases, the lignin must first be extracted before the depolymerizing agents can contact the lignin. These are some of the suitable agents and processes for depolymerizing lightenin. Pandey (2011), Pearl (1942), Liu (2013), Kleen (1991) and Xiang (2000). FIG. 2 shows examples of lignin polymerization methods as well as low molecular weight compounds. 2, and include oxidative methods which provide aldehydes, alcohols, and acids; steam explosion which provides the hemicellulose depolymerization and dehydration product furfural or 5-hydroxymethylfurfural; contacting with ionic liquids and a catalyst which provides phenols; and oxidative methods or pyrolysis with hydrogen which provide aldehydes, alcohols, and carboxylic acids.”
“Depolymerization agents” include any one or more of the following: ionic fluids or mixtures (including the invention’s ionic lichid mixtures), hydrogenolysis (e.g. Hz gas, a hydrogen donor agent such as tetralin or sodium formate), hydrogenolysis (e.g. nitrobenzene), Fenton’s agent (H2O2 or ferrous sulfate), metal organ frameworks of iron or copper, and ammonium hydroxide
“Depolymerization agents may include methods or conditions that produce high yields of aromatics, or higher yields of aromatics than non-aromatic low-molecular weight compounds. Methods and conditions that provide low molecular weight alcohols, aldehydes, or carboxylic acid can be included in depolymerization agents. Depolymerization agents may include methods or conditions that provide low molecular weight aromaticaldehydes, alcohols or carboxylic acid. Other depolymerization agents may include methods and conditions that produce high yields (e.g., 5% or 10%, 15% or 20%, 25% or 30%, 35% or 40%, 45% or 60%, 65% or 70%, 75% or more of aromatic aldehydes or alcohols. Depolymerization agents may include methods and conditions that convert lignin efficiently, such as. Convert 35%, 40% or 50% of the starting material into low molecular-weight compounds.
The present invention may include methods and conditions that produce low molecular-weight aldehydes or low-molecular weight aromatic aldehydes. Depolymerization agents may include methods or conditions that generally yield high amounts of aromatic or aldehydes. Depolymerization agents may also include conditions and methods that produce more aldehydes or carboxylic acid than aldehydes, as well as more aldehydes then alcohols.
“Depolymerization agents” include those methods and conditions described in Pearl (1942). CuSO4 or NaOH can be used to contact lignin, lignocellulosic biomass, and other materials that produce aldehydes. Depolymerization agents such as NaOH and CuSO4 can be used to produce specific aldehydes, including vanillin or syringaldehyde. The methods and conditions for depolymerization agents are also described in Liu (2013). One example is lignin and lignocellulosic biomass may be treated with quaternary ammonium or imidazolium dimethiphosphate ionic fluids. Such conditions are known to efficiently depolymerize lignin and provide aldehydes such as vanillin, p-hydroxybenzaldehyde, and syringaldehyde in moderate yields.”
Villar (2001) describes the conditions and methods for depolymerizing agents according to the invention. You can contact lignin, or lignocellulosic biomass with mild oxidants like nitrobenzene, metallic oxides, and oxygen to make aldehydes. Depolymerization using metal organic frameworks such as Fe3+ or Cu2+ can also be used to oxidize lignin. Alternately, hydrogen peroxide and Fenton’s reactant can be used for oxidative depolymerization of lignin. Another way to oxidize is under alkaline conditions.
The present invention may include methods and conditions that yield low molecular-weight alcohols or low molecular-weight aromatic alcohols. Depolymerization agents may include methods or conditions that generally yield a high yield or high percentage of aromatic alcohols. Depolymerization agents may also include conditions and methods that produce more alcohols or aldehydes than carboxylic acid. Depolymerization may include methods that produce phenols, high yields of phenols or a higher proportion of phenols than aldehydes or carboxylic acid.
Kleen (1991) describes the conditions and methods for depolymerization agents. Fast pyrolysis may be used to depolymerize lignocellulosic biomass. Fast pyrolysis can result in alcohols like 4-Methyl Guaiacol and 4-vinyl-guaiacol. Fast pyrolysis may result in alcohols like guaiacol and 4-vinyl-guaiacol as the predominant products from lignin polymerization. Other cases include pyrolysis which can produce guaiacol and syringol in addition to 4-vinyl-syringol.
“Depolymerization conditions also includes base-catalyzed polymerization as described in U.S. Pat. No. 5,959,167. 5,959,167 Sometimes, the base-catalyzed polymerization can produce a mixture of depolymerized products, including alkylated and alkylatedbenzenes as well as mono, di, tri and polysubstitutedphenols.
“Depolymerization is possible at any temperature, pressure, and pH. The art of depolymerization is possible at any temperature, pressure, or pH. The ionic liquids described herein may be used to pre-treat or depolymerize lignin at a lower temperature or pressure in certain cases.
“Some embodiments of the invention allow the depolymerization products to be converted directly by the subsequent methods into amines and acids suitable for ionic cations or anion respectively. One example is that lignin can be depolymerized. Amination or deprotonation of the depolymerization product may be performed without purifying or substantially purifying the depolymerization product from any other components of the lignocellulosic biomacromolecules. Sometimes, the lignin can be depolymerized. In these cases, amination or protonation can be performed on depolymerization product without purifying or substantially purifying individual depolymerization product or classes of depolymerization (e.g. aldehydes and alcohols, phenols or carboxylic acid).
“In some cases, it may be possible to determine the dominant products of the depolymerization step and use that information to guide subsequent aminations or deprotonation steps. If aldehyde-depolymerization products dominate, then reductive Amination could be used as an appropriate amination step. Alternately, atom-economic hydrotransfer can be used to make tertiaryamines from alcohol depolymerization products. Another example is that phenol alcohols dominate, in which case tertiaryamines can be obtained by converting the phenols into aniline, as described herein. Another example is that if carboxylic acid is present as a predominate component in the mixture depolymerization product, then deprotonation may be used to obtain anions. Alternately, deprotonation or amination may be chosen regardless of or in spite the predominant depolymerization products.
“Alternatively, lignin can be depolymerized so that the depolymerization products may be purified. There are many methods and compositions that can be used to purify lignin-depolymerization products. Sometimes, one or more lignin-derived alcohols, aldehydes or carboxylic acid purification methods may be used.
“In some embodiments, contact the starting material using a depolymerization agents involves contacting it with one or more of these compositions: an imionic liquid, such as an imidazolium-derived ionic fluid; a hydrogen gasoline; an oxygen gas; Fenton?s reagent; or a metal organic framework, such as copper or iron. The depolymerization agent may be a lignin-derived ionic fluid. Some embodiments use an imidazolium-ionic liquid as the depolymerization agent.
“Aldehyde lignin depolymerization products include:”
“”
“Alcohol lignin depolymerization products include p-coumaryl alcohol, coniferyl alcohol, sinapyl alcohol,”
“Wherein R and R?” “, wherein R and R?
“Alcohol-lignin depolymerization products also contain the following phenols”
“Wherein R and R?” independent selection from the group consisting H and OCH3
The following carboxylic acids are included in the “Lignoacid Depolymerization Products of the Present Invention:
“Where R and R?” Each one is selected from the group comprising H, CH3, OH and OCH3.
“In certain cases, lignin-depolymerization products such as vanillin, siringaldehyde or a derivative thereof can be converted into a methoxy (dimethoxy) or trimethoxy derivative. For example, vanillin can be converted into 3,4dimethoxybenzaldehyde. As another example, syringaldehyde can be converted into 3,4,5 trimethoxybenzaldehyde. Methods that are known in the art can be used to convert syringaldehyde. Vanillin, syringaldehyde and/or another lignin-derived aldehyde may be dispersed in aqueous Alkaline Hydroxide (e.g. NaOH), to the which an alkylating agent, such as dimethylsulfate, is added. This reaction should last at least 30 minutes-1 hour. Sometimes, the desired methoxy derivative can be obtained as phase separated oil.
“B. Amination & Deprotonation”
“Lignin depolymerization products (e.g., mono, di, tri, etc. Lignoaldehydes and their methoxy derivatives (or lignoalcohols), can be aminated into amines or ions, e.g. Tertiary amines and quaternary ammoniumions. Some embodiments allow for the formation of tertiary ammonium ions from lignoaldehydes by an amination step. As shown in FIG. 5. For example, furfural, 5-hydroxymethylfurfural, p-hydroxybenzaldehyde, 3-methoxybenzaldehyde, 2,5-dihydroxybenzaldehyde, syringaldehyde, cinnamaldehyde, vanillin, benzaldehyde, or 3-hydroxy, 4-methoxybenzaldehyde may be treated with a secondary amine to produce a tertiary amine. Sometimes, it is possible to purify the tertiary or quaternary ammonium Ions synthesized. They can also be used in reaction vessels without any significant purification, such as for biomass treatment or the synthesis of ionic fluids.
“Suitable secondaryamines (HNR2) may be used to produce a variety of tertiary aminos, depending on the chosen amino-R group. A dialkylamine can be used to make a dialkyl-tertiary amino amine by treating an aldehyde/lignin depolymerization product. There are a variety of dialkylamines that can be used to make dialkylamines. Sometimes, the R groups of the dialkylamines are identical (e.g. diethylamine). In some cases, however, the R groups of the dialkylamine may be different (e.g. N-ethylmethylamine). A mixture of secondary amines can be used in some cases to produce a mixture lignin-derived Tertiary Amins.
“In certain cases, lignin can be used to synthesize secondary amines or mixtures of them by amination with low molecular weight, lignin polymerization with one or several primary amines. Ammonia, ethylamine and methylamine are all suitable primary amines.
“a. Reductive Analysis”
“In some embodiments, the contact of the mixture of aldehyde-containing compounds with an amino is made under reducing conditions. Aldehydes can be aminated with secondary amines to form tertiary compounds via reductive addition. The art identifies the conditions and methods of reductive amination. Reductive amination can be done according to the conditions shown in FIG. 5.”
Summary for “Synthesis and use of lignin-derived compounds to synthesize novel ionic liquids”
“Biorefineries are able to process biological materials, such as lignocellulosic biomass, or any components thereof, in order to extract and create valuable materials. Biorefineries must be able to utilize lignin efficiently. This is an important concept that will improve their economic viability. Lignin can also be extracted from lignocellulosic biomass to make pulp and paper. The pulp and paper industry produces lignins such as kraft lignin (produced via the Kraft process), lignosulfonates (produced, e.g. Alkali lignin is produced by the sulfite-pulping process. The soda process black liquor can be treated with acid and low-sulfonate alkali.lignin. These lignins can be extracted, purified and/or derivatized in the same way as lignocellulosic biomass.
“Lignin from pulp and paper producers and biorefineries is often combusted to produce heat, steam, and electricity. This lignin use has a low economic value compared to other sources such as natural gas, steam, and electricity. Newer, more efficient plants can produce more of lignin than is required for heat, steam and electricity generation. New technologies are required to transform polymeric lignin from biorefineries and pulp or paper producers into higher-value products.
“Lignocellulosic biofuel is made from agricultural wastes, forest residuals, and other dedicated energy crops. It has taken a lot of effort to create methods for producing useful compounds from lignocellulosic biomacromolecules. The recalcitrant nature lignocellulosic biomacromolecules, which are resistant to the breakdown and extraction of useful compounds, is one of the biggest obstacles to the technology’s economic viability. This resistance requires the use of treatment methods to increase the accessibility and depolymerization the lignocellulosic biofuel’s lignin and carbohydrate components. The majority of treatment methods use thermochemical processes, which combine high temperatures and pressures with dilute acids or alkalis to open up the biomass’ structure. These processes require specialized equipment and high energy inputs.
“Ionic liquids (ILs), which are innovative fluids for chemical processing, have recently been developed. Because of their low volatility and potential for recyclability, they are environmentally friendly solvents. ILs have been proven to be a promising technology for treating biomass. They can dissolve crystalline cellulose in biomass under mild conditions.
Although lignocellulosic biomass can be treated with ionic fluids with great success, the process can be time- and energy-intensive. The art requires a process that can produce ionic liquids at a lower price and supplies high-quality, renewable lignin-derived chemicals to improve process economics. These and other requirements are met by the present invention.
“In some embodiments, this invention provides a method for creating an ionic fluid. It involves: Contacting a starting material consisting of lignin with depolymerization agents to depolymerize the plant; contacting the mixture aldehyde-containing compounds with an aldehyde under conditions that convert the mixture to an aldehyde-containing compound to an amine mixture; and finally, contacting the mixture amine-containing compounds with an acid in conditions that form an ammonium salt.
“In some embodiments, this invention provides an ionic fluid. It is prepared by contacting a starting matter comprising lignin with depolymerization agents to depolymerize lignin, and then contacting the mixture aldehyde-containing compounds with an aldehyde under conditions that convert the mixture into a mixture containing amines. Finally, contacting the mixture amine-containing compounds with a mineral acids under conditions that allow for the formation of an ammonium salt.
“In certain embodiments, the invention provides an ionic fluid consisting at least one compound from the following formula:
“wherein each R group of nitrogen is H,CH3, or CH2CH3 and at least two R groups are independently selected from CH3 or CH2CH3 or R?, R?? independent selection from H, OH and OCH3; R4 from H, OH and CH2OH; and X an acid anion.”
“In some instances, the present invention provides a mixture consisting at least two of these ionic liquids. The present invention can provide a mixture that contains at least three of these ionic liquids in some cases. The present invention can provide a mixture that contains at least four of these ionic liquids in some instances. The present invention can provide a mixture that contains at least five of these ionic liquids in some instances. The present invention can provide a mixture that contains at least six of these ionic liquids in some instances. The present invention can provide a mixture that contains at least seven of these ionic liquids in some instances. The present invention can provide a mixture that contains at least eight of these ionic liquids in some instances. In other instances, the present invention allows for a mixture that contains at least nine of these ionic liquids. The present invention can provide a mixture containing at least 10% w/v at least one of the above ionic liquids.
“I. Overview”
“Lignin is the second-most abundant biopolymer on Earth. It is a heterogeneous, heterogeneous macromolecule that consists of three phenylpropane unit (a.k.a. monlignols), p-coumaryl, coniferyl and sinapyl alcohol. (FIG. 1) The monolignol content of lignin is affected by its origin (hardwood, grass or softwood) and the extraction method from biomass.
“Lignin polymerization can be done by a variety of methods, including pyrolysis (e.g. gasification, thermolysis and hydrogenolysis), chemical oxidation, combustion, and ionic liquid-mediated. Different product combinations can be obtained depending on the type of starting material (e.g. hardwood, softwood or grass) as well as the extraction and depolymerization processes.
“Depolymerization may produce aromatic low molecular mass (e.g. monomer, dimer or trimer). Products containing alcohol, aldehyde, and carboxylic acids functional groups. These functional groups may be used as chemical “handles”. These functional groups can be used to convert lignin-derived monmers into ionic fluids. The present invention can provide ionic liquids that are low in molecular weight monomers, dimers, trimers, and so forth. products of lignin polymerization. For example, low molecular weight (e.g., monomer, dimer, trimer, etc.) The present invention allows for the conversion of products of lignin that contain aldehydes and carboxylic acid, as well as alcohols, into ionic fluids. One or more low molecular weight aldehydes and carboxylic acid, as well as alcohols, can be aromatic. Sometimes, the ionic fluids are made from low-cost starting materials (e.g., lignin from a biorefiner or a pulp and paper manufacturer). The present invention allows for the production of ionic liquids at lower costs. The ionic liquids created by the methods described herein may be novel in some instances. Some mixtures of ionic fluids created by the methods described herein may be novel.
The invention’s ionic liquids can be used in any method that is known or envisaged to use ionic liquids. The invention’s ionic liquids can be used to process biomass as a component in a battery electrolyte or as dispersants in the manufacturing of pharmaceuticals, commodity and fine chemicals as well as as a pharmaceutical agent. The invention’s ionic liquids can be made from lignin. They can then be used to extract, dissolve and/or depolymerize the lignin during concurrent or subsequent pretreatment steps. The invention includes a closed loop process to generate ionic fluids from biomass during treatment of additional biomass.
“II. Definitions”
“?Ionic liquid? “?Ionic liquid?” refers to salts which are liquids and not crystals at room temperature. It is obvious to all who are skilled that many ionic liquids may be used in the invention. ChemFiles (2006) 9(9) teaches you about ionic liquids. These are available commercially from Sigma-Aldrich, Milwaukee, Wis. Such ionic liquids include, but are not limited to, 1-alkyl-3-alkylimidazolium alkanoate, 1-alkyl-3-alkylimidazolium alkylsulfate, 1-alkyl-3-alkylimidazolium methylsulfonate, 1-alkyl-3-alkylimidazolium hydrogensulfate, 1-alkyl-3-alkylimidazolium thiocyanate, and 1-alkyl-3-alkylimidazolium halide, wherein an ?alkyl? An alkyl group containing between 1 and 10 carbon atoms. An alkanoate is an alkanoate that contains between 1 and 10 carbon atoms. The alkyl can be an alkyl group that contains between 1 and 4 carbon atoms. The alkyl can be a methyl, ethyl, propyl, or butyl groups in some cases. The alkanoate can be defined as an alkanate that contains between 1 and 4 carbon atoms. The alkanoate can be an acetate in some cases. Sometimes, the halide can be chloride.
“Exemplary ionic liquids include, but are not limited to 1-ethyl-3-methylimidazolium acetate (EMIM acetate) or ([C2mim][OAc]), 1-ethyl-3-methylimidazolium chloride (EMIM Cl), 1-ethyl-3-methylimidazolium hydrogensulfate (EMIM HOSO3), 1-ethyl-3-methylimidazolium methylsulfate (EMIM MeOSO3), 1-ethyl-3-methylimidazolium ethylsulfate (EMIM EtOSO3), 1-ethyl-3-methylimidazolium methanesulfonate (EMIM MeSO3), 1-ethyl-3-methylimidazolium tetrachloroaluminate (EMIM AICl4), 1-ethyl-3-methylimidazolium thiocyanate (EMIM SCN), 1-butyl-3-methylimidazolium acetate (BMIM acetate), 1-butyl-3-methylimidazolium chloride (BMIM Cl), 1-butyl-3-methylimidazolium hydrogensulfate (BMIM HOSO3), 1-butyl-3-methylimidazolium methanesulfonate (BMIM MeSO3), 1-butyl-3-methylimidazolium methylsulfate (BMIM MeOSO3), 1-butyl-3-methylimidazolium tetrachloroaluminate (BMIM AICl4), 1-butyl-3-methylimidazolium thiocyanate (BMIM SCN), 1-ethyl-2,3-dimethylimidazolium ethylsulfate (EDIM EtOSO3), Tris(2-hydroxyethyl)methylammonium methylsulfate (MTEOA MeOSO3), 1-methylimidazolium chloride (MIM Cl), 1-methylimidazolium hydrogensulfate (MIM HOSO3), 1,2,4-trimethylpyrazolium methylsulfate, tributylmethylammonium methylsulfate, choline acetate, choline salicylate, and ionic liquids derived from low molecular weight lignin depolymerization products.”
“?Contacting? Contacting refers to bringing two or more distinct species into contact so that they can react. The reaction product can be made directly from the reaction between the added agents or as an intermediate from any of the additional reagents that can be used in the reaction mixture.
“?Lignin? “?Lignin?” is a phenylpropane-polymer of monolignol singlemers. It is found in the secondary cells of certain plants and some types of algae as an integral part. Three monolignol monomers are methoxylated in different degrees to lignin: p-coumaryl, coniferyl, and sinapyl. These lignols are incorporated into lignin in the form of the phenylpropanoidsp-hydroxyphenyl (H), guaiacyl (G), and syringyl (S), respectively. Gymnosperms have a blend of G and H in their lignin. Monocotyledonous, however, lignin contains a combination of both G and S. While many grasses are mainly G-rich, some palms are primarily S-rich. However, lignins do not contain large amounts of modified or incomplete monolignols. Other monomers are also present in non-woody plants.
“?Depolymerization agent? Any chemical or process that depolymerizes lignin. CuSO4/NaOH (Pearl 1942) and Pandey (2011) are examples of depolymerization agent. Ionic liquids can be used as depolymerization agents, such as alkyl-imidazolium and lignin-derived ionic fluids.
“?Aldehyde? Refers to any organic compound that contains the structure R?CHO. It consists of a carbonyl centre (a carbon double bonded with oxygen) and a R group, which can be any generic side chain.
“?Alkyl? “?Alkyl?” refers to an aliphatic radical that is either straight or branched and has the indicated number of carbon atoms. Any number of carbons can be included in alkyl, including C1-2,C1-3,C1-4,C1-6,C1-5,C1-7,C1-8,C1-9,C1-10,C2-3, C2-4 and C2-6, as well as C2-4,C2-5,C2-6, C3-4,C3-5,C3-6,C4-6,C4-6, and C5-6. C1-6 alkyl can include, but not be limited to: methyl, propyl and ethyl; isopropyl; butyl; isobutyl; sec.butyl; tert.butyl; pentyl. isopentyl. hexyl. Alkyl can also be used to refer to alkyl group with up to 20 carbon atoms. This includes, but is not limited to, heptyl and octyl as well as nonyl and decyl. You can substitute or unsubstitute alkyl groups.
“?Amine? “?Amine” refers to an N(R]2 group, where the R groups may be hydrogen, alkyl or alkenyl and alkynyl. You can have the same R group or you can have different ones. You can have primary or secondary amino groups (each one is hydrogen), or tertiary (each is another than hydrogen). What is a?tertiary amino? An amine with the general formula HNR3 where R is not H. Tertiary ammoniums can be protonated to form cations or non-ionized. A?quaternary amine? An ammonium cation according to the general formula NR4+.
“?Alkyl amine? An alkyl group, as defined in, that contains one or more amino acids. You can choose from primary, secondary, or tertiary amino groups. To make an amino-hydroxy group, the alkylamine can be substituted with a hydro group. The present invention uses alkylamines such as ethylamine, propylamine, isopropylamine, ethylene diamine, and ethanolamine. The amino group can either link the alkylamine to the point where it attaches with the rest, be in the omega position of an alkyl group or link at least two carbon atoms together from the alkyl groups. The present invention is applicable to other alkylamines.
“?Halide? “?Halide” refers to a fluoride or chloride, bromide or iodide ion, or compound.
“?Alkanoate? Refers to an alkane acids of the form R.COO?. The present invention includes alkan0ates that include, but not limited to, acetate.
“?Mineral acids? Inorganic acids are mineral acids. The present invention uses mineral acids such as sulfuric acid and hydrochloric Acid, nitric Acid, boric Acid, phosphoric Acid, hydrofluoric, hydrobromic, and perchloric acids.
“?Hydrogen donating agent? Agents that can participate in hydrogen transfer reactions, or are capable of reducing a reactant. The present invention includes tetralin and sodium formate as hydrogen donating agents. Pandey (2011) describes hydrogen donating agents. They also include active hydrogen donating solvents.
“?Catalyst? A substance that causes or speeds up a chemical reaction. Although catalysts are not usually consumed in chemical reactions, side reactions can inactivate, foul or consume catalysts. The present invention uses nickel, palladium and platinum catalysts. The present invention uses silica-alumina catalysts as well.
“?Oxidizing agent,? ?oxidant,? or ?oxidizer? The term?oxidizer? refers to any substance that removes electrons or removes hydrogen from a reactionant. The electron donating reaction reduces the oxidizing agent and acts as an electron acceptor. The present invention uses O2 gas, H2O2, Fenton?s reagent (H2O2 ferrous sulfate), Fenton’s reagent (H2O2 iron sulfate), and nitrobenzene as oxidizing agents.
“?Metal oxide? The oxide of any alkaline metal like Be, Mg or Ca, Sr, is called “Metal oxide”. Transition metals like Cr, Mn and Fe, Sc, Ti and V, Cr and Ni, Cu and Zn are also useful metals. Examples of metal oxides are MgO and Sb2O3. The present invention is useful for those with skill in the arts.
“?Metal organic framework?” “?Metal organic framework? The term?MOF? refers to compounds that contain metal ions or clusters and are coordinated to organic molecules in order to form porous structures. They are useful for catalysis as well as being lignin-depolymerization agents. The MOFs that are useful in the invention include MOFs made of copper or iron, as described in Masingale 2009”
“?Lignin-derived Ionic Liquid? Any ionic liquid that contains cations (e.g. “tertiary or quaternary aminos or anions” as used herein refers to any ionic liquid containing cations (e.g.
“?Reducing conditions? Reaction conditions are those that accelerate or cause the donation of electrons from a reactant. Reducing conditions useful in the present invention include reactions that contain Hz gas with a suitable catalyst, polymethylhydrosiloxane, sodium cyanoborohydride, sodium borohydride, sodium borohydride-trifluoroacetic acid, and sodium triacetoxyborohydride.”
“?Hydride donating reduction agent?” This refers to reducing agents which donate a hydroide to or reduce a reactant. Hydride donating reducing agents include Hz gas with a suitable catalyst, polymethylhydrosiloxane, sodium borohydride, sodium borohydride-trifluoroacetic acid, and sodium triacetoxyborohydride.”
“A ?salt metathesis reaction? A chemical reaction that involves the exchange of bonds between reacting chemical species. This results in the creation products with identical or similar bonding affiliations. This reaction is represented by the general scheme:\nA?B+C?D?A?D+C?B\nSalt metathesis is a common technique for exchanging counterions between the reacting species.”
“?Polar solvent? “Polar solvent” is a term that refers to solvents having a dielectric constant greater than 15 Protic and aprotic solvents are both polar solvents. ?Protic solvents? These solvents are those that dissolve anions by hydrogen bonding. They include isopropanol and formic acid as well as n-butanol and isopropanol. ?Aprotic solvents? These solvents are used to dissolve cations by interaction with their negative dipole. They include dimethylformamide and acetone as well as acetone, dimethylformamide, dimethyl sulfoxide and propylene carbonate.
“III. Ionic Liquids”
“In certain embodiments, the invention provides an ionic fluid containing at most one compound of this formula:
“Wherein each of R groups of nitrogen are independently selected between H, CH3, and CH2CH3; at least two R groups of nitrogen are independently selected among CH3 or CH2CH3:nR??, R??, or R?? independent selection from H, OH and OCH3;nR4 selected from H and OH; andnX an acid anion.
“In some embodiments the acid anion may be acetic acid (as HCO2?) ), formic acid, as HCO2? ), formic acid (as HCO2? ), citric acid, (e.g. as C3H5O (COO)3 3 ), sulfuric acid (as HSO4 ? ), hydrochloric (as Cl) ), hydrochloric acid (as Cl? ), boric acid, as H2BO3? ), phosphoric (as H2PO4? ), hydrofluoric Acid (as F) ), hydrobromic (as Br?) ), hydrobromic acid (as Br?
“In some embodiments, a mixture contains at least two of these ionic liquids. The present invention may provide a mixture that contains at least three of these ionic liquids in some instances. The present invention may provide a mixture that contains at least four of these ionic liquids in some embodiments. The present invention may provide a mixture that contains at least five of these ionic liquids in some embodiments. The present invention can provide a mixture that contains at least six of these ionic liquids in some embodiments. The present invention may provide a mixture that contains at least seven of these ionic liquids in some embodiments. The present invention may provide a mixture that contains at least eight of these ionic liquids in some embodiments. The present invention may provide a mixture that contains at least nine of these ionic liquids in some embodiments. The present invention can provide a mixture containing about 10% w/v at least one of these ionic liquids.
“In certain embodiments, the invention provides tertiary ionic liquids of ammonium tertiary ionic liquids. Tertiary ammonium isoonic liquids can also be made from lignin-derived materials. The tertiary ammonium ions can be made from low molecular-weight lignoaldehydes and lignoalcohols, for example. The present invention includes the following: Tertiary ammonium-ionic liquids
“where each R group is selected independently from the group consisting CH3 and CH2CH3;nR??, R? R???? and H, OH. R?? ), formic acid, as HCO2? ), formic acid (as HCO2? ), citric acid, (e.g. as C3H5O (COO)3 3 ), sulfuric acid (as HSO4 ? ), hydrochloric (as Cl) ), hydrochloric acid (as Cl? ), boric acid, as H2BO3? ), phosphoric (as H2PO4? ), hydrofluoric Acid (as F) ), hydrobromic (as Br?) ), hydrobromic acid (as Br?
“In some embodiments of the invention, ionic liquids are prepared by”
In some embodiments, the invention allows for multiple cations to be present in ionic liquids. A compound that contains one or several alcohols and one/more phenolic group, a complex containing one/more aldehydes and one/more aldehydes and one/more phenolic group, a composition containing one/more phenolic and/or multiple aldehydes or a compound with multiple aldehydes can be combined to create compounds with multiple secondary amines, multiple anilines or a combination or one/more amines and/or one/more analine These compounds can be converted to ionic fluids by salt formation, as described. In some embodiments, 5-hydroxymethylfurfural can be converted to an ionic liquid containing two cationic functional groups. For example, a compound containing multiple tertiary amines can be synthesized from 5-hydroxymethylfurfural via reductive amination of the aldehyde and direct amination of the alcohol by atom-economic hydrogen autotransfer. Salt formation can sometimes be used to synthesize the appropriate tertiary amine. One or more of the multiple Tertiary Ammonium Amines can be converted to Quaternary Ammonium Ions by, for example, reaction with dimethylcarbonate, or dimethylsulfate.
“Some embodiments of the invention provide quaternary ammonium-ionic liquids. Quaternary ammonium liquids can also be made from lignin-derived materials. The quaternary ammonium can be made from low molecular-weight lignoaldehydes or lignoalcohols, for example. In some instances, the tertiary aminos can be synthesized from low molecularweight lignoaldehydes or lignoalcohols and the quaternary ismonium ionic fluids are created therefrom. The following are examples of quaternary ammonium-ionic liquids according to the present invention:
“where each R group is selected independently from the group consisting CH3 and CH2CH3;nR??, R? R???? and H, OH. R?? ), formic acid, as HCO2? ), formic acid (as HCO2? ), citric acid, (e.g. as C3H5O (COO)3 3 ), sulfuric acid (as HSO4 ? ), hydrochloric (as Cl) ), hydrochloric acid (as Cl? ), boric acid, as H2BO3? ), phosphoric (as H2PO4? ), hydrofluoric Acid (as F) ), hydrobromic (as Br?) ), hydrobromic acid (as Br?
“Some embodiments of the invention provide ionic liquids derived by carboxylic acid products from lignin polymerization. The following are ionic liquids derived from carboxylic acid products of lignin depolymerization that are ionic according to the invention:
“Where each R?” “Where each R?
“The ionic liquids described in the present invention may be used as mixtures in some instances. Mixtures can contain one or several tertiary ionic fluids, one, or more, quaternary ionic liquors, one, or more, lignoacid-derived ionicliquids, or any combination thereof. The ionic fluids of the present invention may include a mixture containing ionic substances with different anions but the same cation. An example of this is an ionic liquid mix containing a Tertiary Ammonium (e.g. a cation form compound 1, 2, 3, 4, 5, 6 7, 8, 8 or 9 of FIG. 4. A tertiary amine of FIG. 7. Or a cation of the tertiaryamines of FIG. 8) or a quadernary ammonium (e.g. a quadernary ammonium of FIG. Complexed with a mixture (e.g., anions phosphoric acid or sulfuric acid) Another example is an ionic liquid mix containing a tertiary and quaternary ammonium. Complexed with a mixture lingoacid-derived anions (e.g. an anion of FIG. 9).”
“In other embodiments, the composition of ionic fluids can contain a mixture of different anion ionic liquids with different cations. Ionic liquids may contain an anion of sulfuric acid or phosphoric acid, and a mixture or cations (e.g. a mixture or one or more of the tertiary or quaternary monium ions). Alternately, the invention’s ionic liquid mixtures can contain a mixture of tertiary or quaternary ammoniumions (e.g. NHR3+ or NR4+) and a combination of lignoacid-derived anion (e.g. an anion of FIG. 9).”
“In other embodiments, the composition of the ionic fluids can contain a mixture of different anions and cations. An example of this is an ionic liquid mix that contains anions (e.g. anions of phosphoric acid and/or sulfuric acid derived anions) as well as a mixture tertiary or quaternary ammonium (e.g. two or more cation forms of compound 1, 2, 3, 4, 5, 6 7, 8, 8 or 9 of FIG. 4; A tertiary amine of FIG. 7; A cation form for a Tertiary Ammonium of FIG. 8; or, a quaternary amine of FIG. 10).”
“In certain embodiments, the thermal stability of the ionic liquids described in the present invention is high. The ionic liquids can have a high peak temperature for thermal decomposition. The Table 1 table shows examples of thermal decomposition temperatures in ionic liquids according to the invention.
“In certain embodiments, the ionic fluids of the present invention may dissolve lignin, as shown in FIG. 6. The ionic liquids can, in some instances, depolymerize the lignin. The ionic fluids of the invention can depolymerize and/or dissolve lignin in some instances. The time and energy required (e.g. heat, pressure, etc.), can determine efficiency. It is possible to depolymerize or dissolve lignin by calculating the time and energy required. The amount (e.g. weight or volume) required to dissolve a certain amount of lignin may also determine efficiency. The maximum amount of dissolved lignin found in any of the ionic liquids, or mixtures thereof, may also determine efficiency.
“IV. “IV. Methods of Preparing Ionic Fluids”
“In certain embodiments, the invention provides methods for generating ionic fluids from depolymerization products lignin. The following method is provided by the present invention in some embodiments:
“Lignin can be obtained by any method that is known to the art. For example, lignin can be extracted from biomass by a biorefinery, pulp or paper manufacturer or other means. Kraft lignin and lignosulfonate are examples of lignins. You can also make lignins from lignocellulosic biomasse, such as ionic liquid treatment.
“In some embodiments, this invention provides a method for extracting lignin lignocellulosic materials. This involves contacting the material with an Ionic Liquid prepared by contacting a material with a depolymerization agent. The mixture of aldehyde-containing compounds is converted to an aldehyde-containing compound mixture. A mixture of amine-containing compounds is then contacted with an acid under conditions that are suitable to form an Ammonium Salt. Sometimes, the method for extracting lignin involves depolymerizing the lignin.
There are two main categories of methods for extracting lignin from lignocellulosic biomacromolecules. Methods in which cellulose and/or hemicellulose are separated by solubilization leave lignin insoluble. The second group comprises methods that dissolve and remove lignin. This leaves cellulose and/or hemicellulose insoluble and then recovers lignin from the solution.
“Alternatively, the starting material for lignin may be provided as lignocellulosic biomasse. Pretreatment of the lignin and lignocellulosic biomass may be done using methods that are known to the art before or concurrently with lignin extract or depolymerization. You can pre-treat the lignin or lignocellulosic biomass by heating, burning, cracking, breaking, sawing, heat, steam explosion, ammonia fibre expansion, micro- or ultrasonic radiation, contact with a dilute, concentrated, or hot acid, CO2, hot or organic water, or any combination of these steps.
“Pretreatment conditions may also include the use of ionic fluids (e.g. Ionic liquids (e.g., those of the prior art) and dilute acids. Examples include 1, 2, 3, 5, 6, 7, 7, 8, 9, 12, 13, 14, 15, 16, 17, 18, 19, and about 20% hydrochloric acids.
Pretreatment can include the use a cosolvent. Water, an organic solvent or an additional ionic fluid can all be co-solvents. A co-solvent may be used in some cases to reduce the volume or concentration requirements of an ionic liquid. The ionic liquids described in the present invention can be used as co-solvents and/or in combination with other co-solvents to treat lignocellulosic biomass.
“A. Depolymerization”
“The present invention offers methods for contacting lignin using a depolymerization agents. Any chemical or process for depolymerizing polymeric, lignin to low molecular-weight compounds (e.g. monomers, dimers and trimers) is considered a depolymerization agent. Sometimes, the depolymerizing agents extract and depolymerize the lignin from a biomass. In some cases, the lignin must first be extracted before the depolymerizing agents can contact the lignin. These are some of the suitable agents and processes for depolymerizing lightenin. Pandey (2011), Pearl (1942), Liu (2013), Kleen (1991) and Xiang (2000). FIG. 2 shows examples of lignin polymerization methods as well as low molecular weight compounds. 2, and include oxidative methods which provide aldehydes, alcohols, and acids; steam explosion which provides the hemicellulose depolymerization and dehydration product furfural or 5-hydroxymethylfurfural; contacting with ionic liquids and a catalyst which provides phenols; and oxidative methods or pyrolysis with hydrogen which provide aldehydes, alcohols, and carboxylic acids.”
“Depolymerization agents” include any one or more of the following: ionic fluids or mixtures (including the invention’s ionic lichid mixtures), hydrogenolysis (e.g. Hz gas, a hydrogen donor agent such as tetralin or sodium formate), hydrogenolysis (e.g. nitrobenzene), Fenton’s agent (H2O2 or ferrous sulfate), metal organ frameworks of iron or copper, and ammonium hydroxide
“Depolymerization agents may include methods or conditions that produce high yields of aromatics, or higher yields of aromatics than non-aromatic low-molecular weight compounds. Methods and conditions that provide low molecular weight alcohols, aldehydes, or carboxylic acid can be included in depolymerization agents. Depolymerization agents may include methods or conditions that provide low molecular weight aromaticaldehydes, alcohols or carboxylic acid. Other depolymerization agents may include methods and conditions that produce high yields (e.g., 5% or 10%, 15% or 20%, 25% or 30%, 35% or 40%, 45% or 60%, 65% or 70%, 75% or more of aromatic aldehydes or alcohols. Depolymerization agents may include methods and conditions that convert lignin efficiently, such as. Convert 35%, 40% or 50% of the starting material into low molecular-weight compounds.
The present invention may include methods and conditions that produce low molecular-weight aldehydes or low-molecular weight aromatic aldehydes. Depolymerization agents may include methods or conditions that generally yield high amounts of aromatic or aldehydes. Depolymerization agents may also include conditions and methods that produce more aldehydes or carboxylic acid than aldehydes, as well as more aldehydes then alcohols.
“Depolymerization agents” include those methods and conditions described in Pearl (1942). CuSO4 or NaOH can be used to contact lignin, lignocellulosic biomass, and other materials that produce aldehydes. Depolymerization agents such as NaOH and CuSO4 can be used to produce specific aldehydes, including vanillin or syringaldehyde. The methods and conditions for depolymerization agents are also described in Liu (2013). One example is lignin and lignocellulosic biomass may be treated with quaternary ammonium or imidazolium dimethiphosphate ionic fluids. Such conditions are known to efficiently depolymerize lignin and provide aldehydes such as vanillin, p-hydroxybenzaldehyde, and syringaldehyde in moderate yields.”
Villar (2001) describes the conditions and methods for depolymerizing agents according to the invention. You can contact lignin, or lignocellulosic biomass with mild oxidants like nitrobenzene, metallic oxides, and oxygen to make aldehydes. Depolymerization using metal organic frameworks such as Fe3+ or Cu2+ can also be used to oxidize lignin. Alternately, hydrogen peroxide and Fenton’s reactant can be used for oxidative depolymerization of lignin. Another way to oxidize is under alkaline conditions.
The present invention may include methods and conditions that yield low molecular-weight alcohols or low molecular-weight aromatic alcohols. Depolymerization agents may include methods or conditions that generally yield a high yield or high percentage of aromatic alcohols. Depolymerization agents may also include conditions and methods that produce more alcohols or aldehydes than carboxylic acid. Depolymerization may include methods that produce phenols, high yields of phenols or a higher proportion of phenols than aldehydes or carboxylic acid.
Kleen (1991) describes the conditions and methods for depolymerization agents. Fast pyrolysis may be used to depolymerize lignocellulosic biomass. Fast pyrolysis can result in alcohols like 4-Methyl Guaiacol and 4-vinyl-guaiacol. Fast pyrolysis may result in alcohols like guaiacol and 4-vinyl-guaiacol as the predominant products from lignin polymerization. Other cases include pyrolysis which can produce guaiacol and syringol in addition to 4-vinyl-syringol.
“Depolymerization conditions also includes base-catalyzed polymerization as described in U.S. Pat. No. 5,959,167. 5,959,167 Sometimes, the base-catalyzed polymerization can produce a mixture of depolymerized products, including alkylated and alkylatedbenzenes as well as mono, di, tri and polysubstitutedphenols.
“Depolymerization is possible at any temperature, pressure, and pH. The art of depolymerization is possible at any temperature, pressure, or pH. The ionic liquids described herein may be used to pre-treat or depolymerize lignin at a lower temperature or pressure in certain cases.
“Some embodiments of the invention allow the depolymerization products to be converted directly by the subsequent methods into amines and acids suitable for ionic cations or anion respectively. One example is that lignin can be depolymerized. Amination or deprotonation of the depolymerization product may be performed without purifying or substantially purifying the depolymerization product from any other components of the lignocellulosic biomacromolecules. Sometimes, the lignin can be depolymerized. In these cases, amination or protonation can be performed on depolymerization product without purifying or substantially purifying individual depolymerization product or classes of depolymerization (e.g. aldehydes and alcohols, phenols or carboxylic acid).
“In some cases, it may be possible to determine the dominant products of the depolymerization step and use that information to guide subsequent aminations or deprotonation steps. If aldehyde-depolymerization products dominate, then reductive Amination could be used as an appropriate amination step. Alternately, atom-economic hydrotransfer can be used to make tertiaryamines from alcohol depolymerization products. Another example is that phenol alcohols dominate, in which case tertiaryamines can be obtained by converting the phenols into aniline, as described herein. Another example is that if carboxylic acid is present as a predominate component in the mixture depolymerization product, then deprotonation may be used to obtain anions. Alternately, deprotonation or amination may be chosen regardless of or in spite the predominant depolymerization products.
“Alternatively, lignin can be depolymerized so that the depolymerization products may be purified. There are many methods and compositions that can be used to purify lignin-depolymerization products. Sometimes, one or more lignin-derived alcohols, aldehydes or carboxylic acid purification methods may be used.
“In some embodiments, contact the starting material using a depolymerization agents involves contacting it with one or more of these compositions: an imionic liquid, such as an imidazolium-derived ionic fluid; a hydrogen gasoline; an oxygen gas; Fenton?s reagent; or a metal organic framework, such as copper or iron. The depolymerization agent may be a lignin-derived ionic fluid. Some embodiments use an imidazolium-ionic liquid as the depolymerization agent.
“Aldehyde lignin depolymerization products include:”
“”
“Alcohol lignin depolymerization products include p-coumaryl alcohol, coniferyl alcohol, sinapyl alcohol,”
“Wherein R and R?” “, wherein R and R?
“Alcohol-lignin depolymerization products also contain the following phenols”
“Wherein R and R?” independent selection from the group consisting H and OCH3
The following carboxylic acids are included in the “Lignoacid Depolymerization Products of the Present Invention:
“Where R and R?” Each one is selected from the group comprising H, CH3, OH and OCH3.
“In certain cases, lignin-depolymerization products such as vanillin, siringaldehyde or a derivative thereof can be converted into a methoxy (dimethoxy) or trimethoxy derivative. For example, vanillin can be converted into 3,4dimethoxybenzaldehyde. As another example, syringaldehyde can be converted into 3,4,5 trimethoxybenzaldehyde. Methods that are known in the art can be used to convert syringaldehyde. Vanillin, syringaldehyde and/or another lignin-derived aldehyde may be dispersed in aqueous Alkaline Hydroxide (e.g. NaOH), to the which an alkylating agent, such as dimethylsulfate, is added. This reaction should last at least 30 minutes-1 hour. Sometimes, the desired methoxy derivative can be obtained as phase separated oil.
“B. Amination & Deprotonation”
“Lignin depolymerization products (e.g., mono, di, tri, etc. Lignoaldehydes and their methoxy derivatives (or lignoalcohols), can be aminated into amines or ions, e.g. Tertiary amines and quaternary ammoniumions. Some embodiments allow for the formation of tertiary ammonium ions from lignoaldehydes by an amination step. As shown in FIG. 5. For example, furfural, 5-hydroxymethylfurfural, p-hydroxybenzaldehyde, 3-methoxybenzaldehyde, 2,5-dihydroxybenzaldehyde, syringaldehyde, cinnamaldehyde, vanillin, benzaldehyde, or 3-hydroxy, 4-methoxybenzaldehyde may be treated with a secondary amine to produce a tertiary amine. Sometimes, it is possible to purify the tertiary or quaternary ammonium Ions synthesized. They can also be used in reaction vessels without any significant purification, such as for biomass treatment or the synthesis of ionic fluids.
“Suitable secondaryamines (HNR2) may be used to produce a variety of tertiary aminos, depending on the chosen amino-R group. A dialkylamine can be used to make a dialkyl-tertiary amino amine by treating an aldehyde/lignin depolymerization product. There are a variety of dialkylamines that can be used to make dialkylamines. Sometimes, the R groups of the dialkylamines are identical (e.g. diethylamine). In some cases, however, the R groups of the dialkylamine may be different (e.g. N-ethylmethylamine). A mixture of secondary amines can be used in some cases to produce a mixture lignin-derived Tertiary Amins.
“In certain cases, lignin can be used to synthesize secondary amines or mixtures of them by amination with low molecular weight, lignin polymerization with one or several primary amines. Ammonia, ethylamine and methylamine are all suitable primary amines.
“a. Reductive Analysis”
“In some embodiments, the contact of the mixture of aldehyde-containing compounds with an amino is made under reducing conditions. Aldehydes can be aminated with secondary amines to form tertiary compounds via reductive addition. The art identifies the conditions and methods of reductive amination. Reductive amination can be done according to the conditions shown in FIG. 5.”
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