Lignin-derived cyclic carbonate monomers

Abstract

In general, the present invention relates to lignin-derived monomers, and polymers prepared with these lignin-derived monomers. In addition, the invention also relates to a method for preparing these monomers from lignin-rich feedstocks, such as lignocellulosic biomass, and to a method for preparing polymers from the monomers obtained.

Description

Field of the Invention

[0001] In general, the present invention relates to lignin-derived monomers, and polymers prepared using these lignin-derived monomers. In addition, the present invention relates to methods for preparing these monomers from lignin-rich feedstocks (e.g., lignocellulosic biomass) and methods for preparing polymers using the obtained monomers. Background of the Invention

[0003] Polyurethane (PU) is a well-known and versatile material that can be found in a wide range of applications such as adhesives, coatings, sealants, flame retardants, elastomers or insulation materials. PU is typically produced by reacting a polyol with a multifunctional isocyanate to result in the formation of urethane bonds. Historically, both the polyol and isocyanate components were petroleum-based, but in recent times, more environmentally sustainable methods of forming PU have emerged.

[0004] Substituting petroleum-based polyols with bio-based polyols has gained a lot of attention. Bio-based polyols used successfully in the preparation of PU materials with high thermal stability and mechanical elasticity are derived from vegetable oils (such as castor oil, soybean oil and tung oil), sugar derivatives and other biopolymers (such as lignin). Due to its high content of hydroxyl groups (both aliphatic and aromatic), lignin is used as a substitute for polyols in the synthesis of various polymers. However, due to the condensation occurring under the harsh reaction conditions of cellulose separation, lignin derived from cellulose separation (also known as industrial lignin) has high molecular weight and polydispersity. As a result, these types of lignin typically lead to poor performance polymers. Lignin-based PU is widely produced from industrial lignin, which is produced from kraft pulp (Kraft) and organic solvent pulping of lignocellulosic biomass. Functional group modification or depolymerization is used to improve the compatibility and reactivity of these lignins in PU formulations, ultimately leading to improved properties of the resulting material. Recent work by the applicant shows that depolymerized natural softwood lignin can be used to improve the compressive strength of partially bio-based PU foams. Examples of mild fractionation and / or depolymerization conditions and strategies to stabilize the intermediates formed during depolymerization lead to a mixture rich in lignin monomers (Chem. Rev. 2018 118, 614; Chem. Soc. Rev. 2018, 47, 852). Depending on the end group on the alkyl chain, these monomers can be divided into two major categories: 4-alkylphenols and 4-hydroxyalkylphenols.

[0005] Compared to the amount of research that has been conducted on bio-based polyols, bio-based isocyanates have received much less attention, with only a few examples available based on, for example, soybean oil, castor oil, oleic acid, and isosorbide.

[0006] Despite this progress on bio-based polyols and isocyanates, the use of toxic isocyanates remains a huge obstacle to the production of more sustainable PU materials with better health and safety qualifications. In recent times, an alternative route to PU materials that has gained increasing attention is the ring opening of cyclic carbonates with diamines to form polyhydroxyurethanes (PHU) by step-growth polymerization. This process is more environmentally sustainable (because it avoids the use of toxic isocyanates), can employ bio-based and recyclable reaction components, and can also use CO2 as a raw material. An additional benefit is the formation of hydroxyl groups in the polymerization reaction, which can subsequently undergo chemical modification to introduce new properties.

[0007] According to a recent discussion by Carré et al. (ChemSusChem 2019, 12, 3410-3430), only a limited number of bio-based PHU materials have been developed and their properties are often not fully studied or reported. The number of examples of polyhydroxycarbamates produced by the reaction of lignin-based cyclic carbonates with polyamines is even more limited. Although PHU formed by the aminolysis of bio-based cyclic carbonates provides an attractive alternative to conventional polyurethanes, studies on petroleum-based PHU have shown several disadvantages of this reaction, including poor reactivity, low degree of polymerization, and limited properties of the resulting PHU at room temperature. The ring opening of cyclic carbonates produces additional hydroxyl groups, which typically results in improved properties (including heat resistance and chemical resistance) of the resulting hydroxy-functionalized polyurethanes compared to their conventional PU counterparts.

[0008] CN105061388A discloses gallic acid-based cyclic carbonate, non-isocyanate polyurethane and preparation method thereof.

[0009] In a publication, Fache et al. (Green Chemistry 2014, 16, 1097-1988) disclose a process for the conversion of vanillyl glycidyl ether into the corresponding cyclic carbonate.

[0010] In a publication, Pu et al. (Catalysis Letters 2020, 150, 2254-2266) disclose a method for converting methoxyphenol glycidyl ether into the corresponding cyclic carbonate.

[0011] It is therefore an object of the present invention to solve the problems associated with conventional and bio-based polyhydroxycarbamates by providing novel lignin-based cyclic carbonates, methods for preparing them and (hybrid) thermosetting polymers resulting from the reaction of lignin-based cyclic carbonates with other monomers. Summary of the invention

[0012] According to a first aspect, the present invention provides a method for preparing a mixture of cyclic carbonates derived from lignin hydrogenolysis oil, the method comprising the steps of: providing glycidyl ethers derived from lignin hydrogenolysis oil into a reaction vessel; adding one or more ionic liquids to the reaction vessel; pressurizing the reaction vessel in the presence of carbon dioxide gas, thereby obtaining a mixture; and heating the mixture to an elevated temperature; wherein the glycidyl ethers derived from the lignin hydrogenolysis oil comprise dihydroconiferyl alcohol glycidyl ether.

[0013] According to an embodiment of the invention, the total amount of the one or more ionic liquids is between 0.1 and 5 molar equivalents, preferably 0.2 to 2.5 molar equivalents, more preferably 0.5 to 1 molar equivalents relative to the glycidyl ether content of the glycidyl ether derived from the lignin hydrogenolysis oil.

[0014] According to an embodiment of the invention, at least two ionic liquids are added to the reaction vessel.

[0015] According to an embodiment of the invention, the one or more ionic liquids are selected from the list comprising tetrabutylammonium bromide, tetrabutylammonium iodide, tetrabutylammonium chloride, tetrabutylammonium fluoride, tributylpropylammonium iodide, N-hexylisoquinoline Aspartic acid, N-octyl-N-methylmorpholine Glutamic acid, 1-butyl-3-methylimidazole Glutamic acid, 1-butyl-3-methylimidazole Aspartic acid, 1-ethyl-3-methylimidazole bromide (1-ethyl-3-methyl imidazol iumbromine)[EMIM][Br], 1-(2-hydroxy-ethyl)-3-methylimidazole bromide (1-(2-hydroxyl-ethyl)-3-methylimdazol ium bromide)(HEMIMB), (triphenyl(ethyl)phosphonium bromide )((triphenyl(ethyl)phosphonium bromide))(PPh3EtBr), 1-butyl-3-methyl-imidazole Hexafluorophosphate [BMIM][PF6]; preferably tetrabutylammonium bromide and tetrabutylammonium iodide.

[0016] According to an embodiment of the invention, the reaction vessel is pressurized with carbon dioxide, typically at room temperature; in particular at room temperature to a pressure between 10 and 80 bar, preferably between 30 and 50 bar.

[0017] According to an embodiment of the invention, the mixture is heated to a temperature between 20 and 150°C, preferably between 70 and 140°C, more preferably between 120 and 130°C.

[0018] According to an embodiment of the invention, the method comprises pressurizing a reaction vessel with carbon dioxide gas to a pressure between 10 and 80 bar, preferably between 30 and 50 bar, at room temperature, thereby obtaining a mixture and heating the mixture to a temperature between 20 and 150°C, preferably between 70 and 140°C, more preferably between 120 and 130°C.

[0019] According to an embodiment of the invention, the glycidyl ether derived from the lignin hydrogenolysis oil is obtained by reacting chlorohydrins derived from the lignin hydrogenolysis oil with a Bronsted base, wherein the chlorohydrins derived from the lignin hydrogenolysis oil comprise dihydroconiferyl alcohol chlorohydrins. According to a specific embodiment of the invention, the amount of the Bronsted base is between 0.5 and 5 molar equivalents, preferably between 0.75 and 3.5 molar equivalents, more preferably between 1 and 2 molar equivalents, relative to the chlorohydrin content of the chlorohydrins derived from the lignin hydrogenolysis oil.

[0020] According to some embodiments of the invention, the Bronsted base is selected from the list comprising: sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium hydride, potassium carbonate. According to a specific embodiment of the invention, the Bronsted base is sodium hydroxide.

[0021] According to another embodiment of the invention, the chlorohydrin derived from the lignin hydrogenolysis oil is obtained by reacting the lignin hydrogenolysis oil containing dihydroconiferyl alcohol with an epoxidant. According to a specific embodiment of the invention, the amount of the epoxidant is between 1 and 50 molar equivalents, preferably 2 to 25 molar equivalents, more preferably 5 to 10 molar equivalents relative to the hydroxyl content of the lignin hydrogenolysis oil.

[0022] According to some embodiments of the invention, the epoxidizing agent is selected from the list comprising: epichlorohydrin, epibromohydrin. According to a specific embodiment of the invention, the epoxidizing agent is epichlorohydrin.

[0023] According to yet another embodiment of the invention, the lignin hydrogenolysis oil comprising dihydroconiferyl alcohol is obtained by depolymerization of a mixture containing lignin, more particularly by metal-catalyzed hydrogenolysis of lignin, a mixture containing lignin or a lignocellulosic biomass.

[0024] According to a further aspect, the present invention provides a cyclic carbonate mixture derived from a lignin hydrogenolysis oil obtainable by an embodiment of the method of the present invention. In a particular aspect, the present invention provides a cyclic carbonate mixture derived from a lignin hydrogenolysis oil comprising dihydroconiferyl alcohol cyclic carbonate obtainable by an embodiment of the method of the present invention.

[0025] According to yet another aspect, the present invention provides a lignin hydrogenolysis oil derived cyclic carbonate mixture comprising dihydroconiferyl alcohol cyclic carbonate.

[0026] According to another aspect, the present invention provides a polymer comprising a mixture of cyclic carbonates derived from lignin hydrogenolysis oil according to an embodiment of the invention. According to some embodiments of the invention, the polymer is selected from a list comprising polyurethanes, polycarbonates, hydroxyurethanes, epoxy resins, epoxy-amine resin systems, mixed non-isocyanate urethane networks, acrylic resins, latex, or any copolymers thereof.

[0027] BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Now with specific reference to the accompanying drawings, it is emphasized that the details shown are by way of example and are only used for the purpose of illustrative discussion of different embodiments of the present invention. They are presented in order to provide what are considered to be the most useful and easy descriptions of the principles and concepts of the present invention. In this regard, no attempt is made to illustrate the structural details of the present invention in more detail than is necessary for a basic understanding of the present invention. The description in conjunction with the accompanying drawings makes it clear to those skilled in the art how several forms of the present invention can be implemented in practice.

[0029] Figure 1 The results show the structure of dihydroconiferyl alcohol (DCA) (A), lignin hydrogenolysis oil (LHO) (B), lignin hydrogenolysis oil chlorohydrin (LHO-CH) (C), lignin hydrogenolysis oil glycidyl ether (LHO-GE) (D) and lignin hydrogenolysis oil cyclic carbonate (LHO-CC) (E). 1 H NMR spectrum.

[0030] Figure 2 IR spectra of LHO, LHO-CH, LHO-GE and LHO-CC are shown.

[0031] Figure 3 Shown is a schematic illustration of a cyclic carbonate / epoxy hybrid thermoset containing LHO-CC. DETAILED DESCRIPTION OF THE INVENTION

[0033] The present invention will now be further described. In the following chapters, different aspects of the present invention are defined in more detail. Each aspect so defined can be combined with any other one or more aspects, unless clearly indicated to the contrary. In particular, any feature indicated as preferred or advantageous can be combined with any other one or more features indicated as preferred or advantageous.

[0034] The compounds of the present invention can be prepared according to the reaction schemes provided in the examples below, but one skilled in the art will appreciate that these are merely illustrative of the present invention and that the compounds of the present invention can be prepared by any of several standard synthetic methods commonly used by those skilled in the art of organic chemistry.

[0035] According to a first aspect, the present invention provides a method for preparing a mixture of cyclic carbonates derived from lignin hydrogenolysis oil, the method comprising the following steps: providing glycidyl ether derived from lignin hydrogenolysis oil into a reaction vessel; adding one or more ionic liquids to the reaction vessel; pressurizing the reaction vessel in the presence of carbon dioxide gas, thereby obtaining a mixture; heating the mixture to an elevated temperature; wherein the glycidyl ether derived from the lignin hydrogenolysis oil comprises dihydroconiferyl alcohol glycidyl ether.

[0036] The prefix "lignin-derived" refers to any product or mixture of products resulting from the pretreatment, modification, functionalization, depolymerization, conversion, degradation, hydrolysis, extraction and / or dissolution of lignin, a mixture containing lignin or lignocellulosic biomass. Typical but non-limiting examples of lignocellulosic biomass are softwoods, hardwoods, crops, trees, shrubs, grasses, agricultural residues and waste wood. Typical but non-limiting mixtures containing lignin are mixtures resulting from various (pulping) processes such as kraft lignin, black liquor, lignin sulfonates, organosolv lignin, hydrolyzed lignin, soda lignin, steam explosion lignin.

[0037] The term "lignin hydrogenolysis oil" is a term known in the art and refers to a mixture of lignin monomers, dimers and oligomers obtained by metal-catalyzed hydrogenolysis of lignin, mixtures containing lignin or lignocellulosic biomass, such as described by Torr et al. (Bioresource Technology 102(16):7608-11). Lignin hydrogenolysis oil is characterized by containing dihydroconiferyl alcohol as one of its components.

[0038] The term "ionic liquid" is understood as an ionic compound having anionic and cationic parts which is substantially liquid at the reaction temperature. The ionic liquid may for example have a melting point below 200°C, preferably below 175°C and more preferably below 150°C at atmospheric pressure.

[0039] During the experiment, surprisingly found that: in contrast to the prior art related to the cyclic carbonation of epoxides derived from lignin, very low amounts of ionic liquids (even as low as catalytic amounts) are sufficiently effective in converting the glycidyl ethers derived from lignin hydrogenolysis oil into cyclic carbonate mixtures derived from lignin hydrogenolysis oil in the presence of carbon dioxide gas. The gas used to pressurize the reaction vessel can be carbon dioxide gas, but it can also be a mixture of carbon dioxide gas and an inert gas (e.g., nitrogen). The gas preferably used to pressurize the reaction vessel is substantially composed of carbon dioxide gas, relative to the gross weight of the gas mixture, for example, greater than 80 wt %, preferably greater than 85 wt %, even more preferably greater than 90 wt %, still even more preferably 95-100 wt %, most preferably between 95 and 99 wt %. Due to such a small amount of ionic liquid, the processing (work-up) of the reaction mixture is greatly improved, resulting in a better yield of the cyclic carbonate mixture derived from the obtained lignin hydrogenolysis oil.

[0040] According to an embodiment of the invention, the total amount of the one or more ionic liquids is between 0.1 and 5 molar equivalents, preferably 0.2 to 2.5 molar equivalents, more preferably 0.5 to 1 molar equivalents relative to the glycidyl ether content of the glycidyl ether derived from the lignin hydrogenolysis oil.

[0041] According to a specific embodiment of the invention, at least two ionic liquids are added to the reaction vessel. According to another specific embodiment of the invention, two ionic liquids are added to the reaction vessel. According to yet another specific embodiment of the invention, the two ionic liquids are added to the reaction vessel separately or as a mixture. According to yet another specific embodiment of the invention, three or more ionic liquids are added to the reaction vessel.

[0042] According to an embodiment of the invention, the one or more ionic liquids are each independently selected from the list comprising tetrabutylammonium bromide, tetrabutylammonium iodide, tetrabutylammonium chloride, tetrabutylammonium fluoride, tributylpropylammonium iodide, N-hexylisoquinoline Aspartic acid, N-octyl-N-methylmorpholine Glutamic acid, 1-butyl-3-methylimidazole Glutamic acid, 1-butyl-3-methylimidazole Aspartic acid, 1-ethyl-3-methylimidazole bromide [EMIM][Br], 1-(2-hydroxy-ethyl)-3-methylimidazole bromide (HEMIMB), (triphenyl(ethyl)phosphonium bromide )(PPh3EtBr), 1-butyl-3-methyl-imidazole Hexafluorophosphate [BMIM][PF6]; preferably tetrabutylammonium bromide and tetrabutylammonium iodide.

[0043] According to a particular embodiment of the invention, ionic liquids tetrabutylammonium bromide and tetrabutylammonium iodide are added to the reaction vessel, wherein the total amount of tetrabutylammonium bromide and tetrabutylammonium iodide is between 0.5 and 1 molar equivalent relative to the glycidyl ether content of the glycidyl ethers derived from the lignin hydrogenolysis oil.

[0044] The hydroxyl content of lignin oil is determined by quantifying 31 P NMR spectroscopy is the molar equivalent of phenolic OH-groups determined according to the experimental protocol reported by van de Pas et al. using endo-N-hydroxy-5-norbornene-2,3-dicarboximide as internal standard. Subsequently, the chlorohydrin content of chlorohydrin derived from lignin hydrogenolysis oil refers to the molar equivalent of chlorohydrin structural parts produced by quantitative conversion of lignin hydrogenolysis oil containing dihydroconiferyl alcohol into chlorohydrin derived from lignin hydrogenolysis oil. Finally, the glycidyl ether content of glycidyl ether derived from lignin hydrogenolysis oil refers to the molar equivalent of epoxide structural parts produced by quantitative conversion of chlorohydrin derived from lignin hydrogenolysis oil into glycidyl ether derived from lignin hydrogenolysis oil.

[0045] According to an embodiment of the invention, the reaction vessel is pressurized with carbon dioxide to a pressure between 10 and 80 bar, preferably between 30 and 50 bar, at room temperature.

[0046] According to an embodiment of the invention, the mixture, in particular the pressurized mixture, is heated to a temperature between 20 and 150°C, preferably between 70 and 140°C, more preferably between 120 and 130°C.

[0047] According to a specific embodiment of the invention, the method comprises the following steps: providing a glycidyl ether derived from lignin hydrogenolysis oil as provided herein into a reaction vessel; adding ionic liquids tetrabutylammonium bromide and tetrabutylammonium iodide to the reaction vessel, wherein the total amount of the ionic liquids (i.e., tetrabutylammonium bromide and tetrabutylammonium iodide) is between 0.5 and 1 molar equivalents relative to the glycidyl ether content of the glycidyl ether derived from the lignin hydrogenolysis oil; preferably at room temperature, pressurizing the reaction vessel with carbon dioxide gas to a pressure between 30 and 50 bar, thereby obtaining a mixture; and heating the mixture to a temperature between 120 and 130°C.

[0048] According to an embodiment of the invention, the glycidyl ether derived from the lignin hydrogenolysis oil is obtained by reacting chlorohydrins derived from the lignin hydrogenolysis oil with a Bronsted base, wherein the chlorohydrins derived from the lignin hydrogenolysis oil comprise dihydroconiferyl chlorohydrins. According to a specific embodiment of the invention, the amount of the Bronsted base is between 0.5 and 5 molar equivalents, preferably between 0.75 and 3.5 molar equivalents, more preferably between 1 and 2 molar equivalents, relative to the chlorohydrin content of the chlorohydrins derived from the lignin hydrogenolysis oil.

[0049] According to some embodiments of the invention, the Bronsted base is selected from the list comprising: sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium hydride, potassium carbonate. According to a specific embodiment of the invention, the Bronsted base is sodium hydroxide.

[0050] According to another embodiment of the invention, the chlorohydrin derived from the lignin hydrogenolysis oil is obtained by reacting a lignin hydrogenolysis oil containing dihydroconiferyl alcohol with an epoxidant. According to a specific embodiment of the invention, the amount of the epoxidant is between 1 and 50 molar equivalents, preferably 2 to 25 molar equivalents, more preferably 5 to 10 molar equivalents relative to the hydroxyl content of the lignin hydrogenolysis oil. According to some embodiments of the invention, the epoxidant is selected from a list comprising the following substances: epichlorohydrin, epibromopropane. According to a specific embodiment of the invention, the epoxidant is epichlorohydrin.

[0051] According to yet another embodiment of the invention, the lignin hydrogenolysis oil comprising dihydroconiferyl alcohol is obtained by depolymerization of a mixture containing lignin, more specifically by metal-catalyzed hydrogenolysis of lignin, a mixture containing lignin or lignocellulosic biomass.

[0052] According to a further aspect, the present invention provides a mixture of cyclic carbonates derived from lignin hydrogenolysis oil obtainable by embodiments of the process of the present invention.

[0053] A non-limiting representation of the conversion steps used to prepare LHO-CC is shown in Scheme 1. For simplicity, LHO is represented as dihydroconiferyl alcohol (DCA), which is the major monomer component of lignin hydrogenolysis oil.

[0054]

[0055] Solution 1.

[0056] According to yet another aspect, the present invention provides a lignin hydrogenolysis oil derived cyclic carbonate mixture comprising dihydroconiferyl alcohol cyclic carbonate.

[0057] According to another aspect, the present invention provides a polymer comprising a mixture of cyclic carbonates derived from lignin hydrogenolysis oil according to an embodiment of the invention. According to some embodiments of the invention, the polymer is selected from a list comprising polyurethanes, polycarbonates, hydroxyurethanes, epoxy resins, epoxy-amine resin systems, mixed non-isocyanate urethane networks, acrylic resins, latex, or any copolymers thereof. Example

[0058] Material

[0059] Epichlorohydrin (ECH) was obtained from Advanced Biochemical (Thailand) Co., Ltd. Tetrabutylammonium iodide (TBAI), tetrabutylammonium bromide (TBAB), chromium acetylacetone, endo-N-hydroxy-5-norbornene-2,3-dicarboximide, pyridine, deuterated chloroform (CDCl3), 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane, sodium hydroxide (NaOH), magnesium sulfate (MgSO4), glycerol diglycidyl ether (GDGE, EEW = 143 g / eq), 1,2-epoxy-3-phenoxypropane, diethylenetriamine (DETA), tris(2-aminoethyl)amine (TAEA) and Pd / C (5 wt% loading) were purchased from Sigma Aldrich. Ethyl acetate (EtOAc), tetrahydrofuran (THF), and 2-propanol were obtained from Merck and used as received.

[0060] analyze

[0061] The total lignin content was determined in duplicate as the sum of Klason lignin (acid-insoluble) and acid-soluble lignin according to the method used in previous work (Green Chem. 2012, 14, 1447). The spectroscopy was performed using an AVIII 400 MHz spectrometer (Bruker, Switzerland) equipped with a Prodigy 5 mm broadband probe. 1 H. 13 C. HSQC and 31 P NMR spectrum.

[0062] Use quantitative 31 P NMR spectroscopy The hydroxyl content of LHO and LHOGE was determined according to the experimental protocol reported by van de Pas et al. (2014) (Holzforschung 2014, 68, 151) using endo-N-hydroxy-5-norbornene-2,3-dicarboximide as internal standard.

[0063] Gas chromatography / mass spectrometry (GC / MS) analysis of the silylated hydrogenolysis oil was performed in duplicate on a 7890B gas chromatograph (Agilent, USA) equipped with a 5977B mass selective detector using an HP-Ultra 2 capillary column. Silylated tert-butylphenol was used as an internal standard to quantify the product.

[0064] In the presence of a 3 μm SDV guard column and two 3 μm SDV Gel permeation chromatography (GPC) was performed using a Smartline GPC system (Knauer, Germany) on a column set consisting of 10 columns (Polymer Standards Service, Germany). The eluent was tetrahydrofuran at 30 °C and the flow rate was 1 mL min -1 . Use oligomeric polystyrene standards (Germany, Polymer Standards Service, ReadyCal Kit) and 4-n-propylguaiacol to construct a calibration curve. The products eluted from the column system are detected by UV (254 and 280nm) and RI detection. The results of RI detection are reported as different hydrogenolysis reactions give products with different UV reactions relative to concentration.

[0065] The chlorine content was determined by the Campbell Microanalytical Lab (University of Otago, New Zealand) according to Celon and Bresadola (Microchim. Acta 1969, 57, 441).

[0066] The EEW of epoxy resins was determined in triplicate by potentiometric titration according to ASTM standard D1652-97 (1997) scaled down to analyze 20 mg samples.

[0067] Example 1

[0068] Pinus radiata wood was extracted with dichloromethane and ground to pass through a 20 mesh screen (lignin content = 28.4 wt % based on oven dry weight).

[0069] 4L titanium autoclave is equipped with this pre-extracted pine (110.0g, 6 wt % moisture content), Pd / C catalyst (4.3g, 4.2 wt % dry wood) and ethanol / water (1:1v / v, 2.4L). Set to stir at 750rpm. First use N2 and then use H2 to pressurize the reactor to 5 bar and purge three times. Then use H2 to pressurize the reactor to~35 bar (500psi) and maintain pressure by continuous supply of H2 during the reaction. Under stirring, the mixture is heated to 195℃ for 5h. Reactor is cooled to room temperature and the reaction mixture is filtered to remove unreacted wood and spent catalyst. This solid residue is rinsed with ethanol / water (7:3v / v) mixture, and rinses and filtrate are combined. Solvent is evaporated under reduced pressure to produce oily product (extracted with ethyl acetate (EtOAc) and water). The EtOAc extract was dried to constant weight to yield lignin hydrogenolysis oil (LHO) (16.8 g) as a dark amber oil with hydroxyl content = 7.73 mmol / g or 129 g / eq.

[0070] Example 2

[0071] For this example, unextracted Mondari pine wood (0.25<particle size<0.5 mm, lignin content=28.3 wt%) was used.

[0072] The 50L stainless steel reactor is equipped with unextracted pine (1.375kg, 6 wt % moisture content), Pd / C catalyst (54.3g, 4.2 wt % dry wood) and ethanol / water (7:3v / v, 30L). Set to stir at 128rpm and purge reactor as above with N2 and H2. Reactor is pressurized to 21 ± 1 bar (290psi) with H2 and pressure is maintained during reaction. Under agitation, reaction mixture is heated to 196 ± 3 ℃ for 20h. Filter the reaction mixture of cooling by 212 μm sieve and glass filter paper respectively, to reclaim unreacted wood and spent catalyst. Reclaim lignin hydrogenolysis oil (LHO) as described above.

[0073] Example 3

[0074] In a 250 mL three-necked round-bottom flask, LHO (12.02 g), epichlorohydrin (36.7 mL, 10 mol equivalents (eq.) relative to the phenolic hydroxyl group content of LHO) and tetrabutylammonium bromide (4.5 g, 0.3 mol eq.) were dissolved in 2-propanol (70 mL) and stirred at 80° C. for 24 h under reflux. The mixture was cooled to 25° C. and concentrated in vacuo, after which the residue was redissolved in EtOAc and rinsed thoroughly with distilled water. The organic phase was concentrated in vacuo to produce a product (13.6 g) as a dark brown oil, which was mainly composed of lignin hydrogenolysis oil epichlorohydrin (LHO-CH) with a smaller amount of lignin hydrogenolysis oil glycidyl ether (LHO-GE).

[0075] Table 1. Optimized reaction conditions for the reaction of LHO with ECH. Calculated values ​​relative to the phenolic hydroxyl groups of LHO

[0076]

[0077] Example 4

[0078] In a 1L three-necked round-bottom flask, crude LHO-CH (12.281 g) was dissolved in THF (658 mL) and treated with an aqueous solution of NaOH (11.55 mL, 20%, w / w) at a rate of 0.2 mL / min at 60°C. After addition of the NaOH solution (approximately 1 h), the reaction mixture was stirred at 60°C for another 3 h. The solvent was removed under reduced pressure and the residual product was redissolved in EtOAc. The organic phase was rinsed with distilled water, dried over MgSO4 and concentrated in vacuo to yield lignin hydrogenolysis oil glycidyl ether (LHO-GE) (7.682 g, 74%) as an orange oil.

[0079] Example 5

[0080] A stainless steel autoclave was charged with LHO-GE (2.615 g), a mixture of TBAB and TBAI (3.23 g, 1:1 w / w). The autoclave was pressurized with CO2 (50 bar) and finally heated to 120°C for 2.5 h. After the reaction mixture was cooled down to 25°C overnight, the residue was redissolved in EtOAc, rinsed with distilled water, dried over MgSO4 and the solvent removed under reduced pressure to produce lignin hydrogenolysis oil cyclic carbonate (LHO-CC) brown oil (2.585 g, 87%).

[0081] Example 6

[0082] In a 1 mL glass bottle, LHO-GE or LHO-CC, GDGE (Table 1) and 0.06 g of 1,2-epoxy-3-phenoxypropane were mixed at 90°C for approximately 10 min. The mixture was cooled to 25°C and DETA or TAEA (Table 1) was added. The mixture was briefly mixed with a spatula, centrifuged at 4000 rpm for 3 min, and then carefully poured into a silicone mold. The resin was cured at 40°C for 20 h and then at 120°C for 24 h to produce a bio-based thermoset. The ratio between LHO-CC and GDGE was varied between 1:2, 1:1 and 2:1, which corresponds to LHO-CC contents of 33, 50 and 66 wt % relative to GDGE (Table 1).

[0083] Table 2. Amounts of reactants used to prepare thermosets

[0084]

[0085]

[0086] a Add 60 mg of 1,2-epoxy-3-phenoxypropane as a reaction diluent; b The amount of amine was calculated by considering the active hydrogen groups of the amine to the cyclic carbonate (active hydrogen equivalent weight, or AHEW = 1) and the epoxy groups (AHEW = 2). The epoxy equivalent weight (EEW) of LHO-GE was 337 g / eq, while the carbonate equivalent weight (CEW) of LHO-CC was 381 g / eq.

[0087] Thermal properties

[0088] Table 3. Thermal properties of LHO-CC / GDGE and LHO-GE / GDGE composites cured with DETA

[0089]

[0090] Table 4. Thermal properties of LHO-CC / GDGE and LHO-GE / GDGE composites cured with TAEA

[0091]

[0092]

[0093] Mechanical properties

[0094] Table 5. Thermomechanical and flexural properties of DETA-cured LHO-CC / GDGE and LHO-EP / GDGE composites with different mixing ratios

[0095]

[0096] a (%,w / w); b Glass transition temperature; c Storage modulus; d Crosslink density

[0097] Table 6. TAEA-cured LHO-CC / GDGE and Thermal conductivity of LHO-GE / GDGE composites Mechanical and flexural properties

[0098]

[0099] a (%,w / w); b glass transition temperature determined by DMTA; c Storage modulus; d Crosslink density

[0100] Example 7

[0101] In a scintillation vial, LHO-CC (0.15 g, 3.4 mmol, EEW = 422 g / eq), diamine (HMDA (hexamethylenediamine), IPDA (isophoronediamine) or MXDA (m-xylene diamine)) were added in a 1:1.05 ratio between cyclic carbonate and amine functional groups and in 10 mol% triazabicyclodecene (TBD). The reaction was carried out at 80°C for 72 h, followed by precipitation in distilled water and subsequent drying of the product at 80°C in vacuum for 24 h before further characterization.

[0102] Table 7. GPC data obtained from PHU obtained from the reaction of LHO-CC with different diamines

[0103]

Claims

1. A method for preparing a cyclic carbonate mixture derived from lignin hydrogenolysis oil, the method comprising the following steps: - providing glycidyl ether derived from lignin hydrogenolysis oil into a reaction vessel; - adding one or more ionic liquids to the reaction vessel; - pressurizing the reaction vessel in the presence of carbon dioxide gas, thereby obtaining a mixture; and - heating the mixture to an elevated temperature; The glycidyl ether derived from the lignin hydrogenolysis oil comprises dihydroconiferyl alcohol glycidyl ether.

2. The method according to claim 1, wherein the total amount of the one or more ionic liquids is between 0.1 and 5 molar equivalents, preferably 0.2 to 2.5 molar equivalents, more preferably 0.5 to 1 molar equivalent, relative to the glycidyl ether content of the glycidyl ether derived from lignin hydrogenolysis.

3. The method according to any one of claims 1-2, wherein at least two ionic liquids are added to the reaction vessel.

4. The method according to any one of claims 1 to 3, wherein the ionic liquid is selected from the list comprising tetrabutylammonium bromide, tetrabutylammonium iodide, tetrabutylammonium chloride, tetrabutylammonium fluoride, tributylpropylammonium iodide, N-hexylisoquinoline Aspartic acid, N-octyl-N-methylmorpholine Glutamic acid, 1-butyl-3-methylimidazole Glutamic acid, 1-butyl-3-methylimidazole Aspartic acid, 1-ethyl-3-methylimidazole bromide [EMIM][Br], 1-(2-hydroxy-ethyl)-3-methylimidazole bromide (HEMIMB), (triphenyl(ethyl)phosphonium bromide )(PPh3EtBr), 1-butyl-3-methyl-imidazole Hexafluorophosphate [BMIM][PF6]; preferably tetrabutylammonium bromide and tetrabutylammonium iodide.

5. The process according to any one of claims 1 to 4, wherein the reaction vessel is pressurized with carbon dioxide at room temperature to a pressure between 10 and 80 bar, preferably between 30 and 50 bar.

6. The process according to any one of claims 1 to 5, wherein the mixture is heated to a temperature between 20 and 150°C, preferably between 70 and 140°C, more preferably between 120 and 130°C.

7. The method according to any one of claims 1 to 6, wherein the lignin hydrogenolysis oil-derived glycidyl ether is obtained by reacting lignin hydrogenolysis oil-derived chlorohydrins with a Bronsted base, wherein the lignin hydrogenolysis oil-derived chlorohydrins comprise dihydroconiferyl alcohol chlorohydrins.

8. The method according to claim 7, wherein the amount of the Bronsted base is between 0.5 and 5 molar equivalents, preferably 0.75 to 3.5 molar equivalents, more preferably 1 to 2 molar equivalents, relative to the chlorohydrin content of the chlorohydrin derived from the lignin hydrogenolysis oil.

9. The method according to any one of claims 7-8, wherein the Bronsted base is selected from the list comprising: sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium hydride, potassium carbonate; preferably sodium hydroxide.

10. The method according to any one of claims 7 to 9, wherein the lignin hydrogenolysis oil derived chlorohydrin is obtained by reacting a lignin hydrogenolysis oil comprising dihydroconiferyl alcohol with an epoxidizing agent.

11. The method according to claim 10, wherein the amount of the epoxidant is between 1 and 50 molar equivalents, preferably 2 to 25 molar equivalents, more preferably 5 to 10 molar equivalents, relative to the hydroxyl content of the lignin hydrogenolysis oil.

12. The method according to any one of claims 10-11, wherein the epoxidizing agent is selected from the list comprising: epichlorohydrin, epibromohydrin; preferably epichlorohydrin.

13. A mixture of cyclic carbonates derived from lignin hydrogenolysis oil, comprising dihydroconiferyl alcohol cyclic carbonate.

14. A polymer comprising the cyclic carbonate mixture derived from lignin hydrogenolysis oil according to claim 13, wherein the cyclic carbonate mixture derived from lignin hydrogenolysis oil comprises dihydroconiferyl alcohol cyclic carbonate.

15. The polymer according to claim 14, selected from the list comprising polyurethanes, polycarbonates, hydroxy urethanes, epoxies, epoxy-amine resin systems, hybrid non-isocyanate urethane networks, acrylics, latexes.

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