New technology of coal-based methanol formaldehyde to methyl acrylate and co-production of lactic acid propylene glycol and epoxy propylene

Abstract

The present application relates to the field of new material industrial chemicals, and particularly relates to a technology solution for manufacturing acrylic ester, methyl methacrylate (MMA), lactic acid ester, 1,2-propylene glycol, propylene oxide and other characteristic C3 products from coal-based methanol and formaldehyde bulk C1 raw materials, and co-production. Compared with traditional petroleum refining processes, the coal-based new process and method disclosed in the present application achieves outstanding cost reduction and efficiency improvement.

Description

[Technical Field]

[0001] This invention relates to the field of new materials industrial chemicals, and particularly to the production of characteristic C3 products such as acrylates, methyl methacrylate (MMA), lactates, 1,2-propanediol, and propylene oxide from bulk C1 raw materials such as coal-based methanol and formaldehyde, as well as their co-production technology solutions. Compared with traditional petroleum refining processes, the new coal-based processes and methods disclosed in this invention achieve significant cost reduction and efficiency improvement results. [Background Technology]

[0002] Any substance that can be manufactured in the petroleum refining industry chain can also be manufactured in the coal-based industry chain, and at a lower cost and with increased efficiency. We are staunch believers and practitioners of this industry philosophy.

[0003] my country's basic energy structure, characterized by abundant coal, scarce oil, and limited natural gas, has established the dominance of coal resources. Coal-based chemicals have achieved significant development over the past few decades, particularly with breakthroughs and large-scale production of key technologies such as methanol / formaldehyde from coal-based syngas, demonstrating strong industrial strength and resource-enabling potential. The unique raw materials and downstream products of the coal chemical industry chain are receiving increasing attention, aiming to reduce dependence on imported oil and gas refining products and to further translate resource advantages into cost competitiveness. In this industrial context, technological innovation is at the core.

[0004] As is well known to industry professionals, acrylic acid and acrylates are typically manufactured from petrochemical C3 propylene raw materials. Propylene then yields bulk products including propylene oxide and 1,2-propanediol. Lactic acid esters are mainly produced through so-called bio-based processes, particularly corn fermentation. All of these technologies face widespread pressure to reduce costs and increase efficiency, as well as the existing technological dilemma of "competing with farmers for food."

[0005] Existing manufacturing technologies for methyl methacrylate (MMA) include the acetone cyanohydrin method, the ethylene hydroformylation carbonylation method, the formaldehyde acetate method, and the isobutylene oxidation method. These processes generally suffer from significant drawbacks, such as the use of highly toxic substances or complex catalysts, lengthy process steps, and high production and environmental costs.

[0006] Coal-based C1 raw materials, particularly those in the so-called "syngas → methanol → formaldehyde" industrial chain, are a valuable resource with the largest production scale and lowest cost in basic coal chemical production, and are well-known to industry professionals. However, to date, no reports have revealed how to prepare the aforementioned high-value-added C3 series products from these abundant C1 raw materials in my country. If this could be achieved, it would have significant industrial implications, not only benefiting the transformation and upgrading of my country's coal chemical industry and reducing the country's energy dependence on petrochemical and oil and gas resources, but also providing new, highly competitive technological solutions based on the superior cost advantage of C1 raw materials.

[0007] This application reveals that, through ingenious reaction principle design and practical exploration, it is possible to efficiently prepare characteristic C3 products such as acrylates, methyl methacrylate (MMA), lactic acid esters, propylene glycol, and propylene oxide using only the most inexpensive and readily available C1 raw materials in industry, particularly representative bulk industrial products such as carbon monoxide, carbon monoxide / hydrogen (syngas), methanol, or formaldehyde, through an unexpectedly simple and flexible shared process. This first-time disclosed technology boasts outstanding process safety, environmental friendliness, and overall cost competitiveness. The C1 raw materials involved have abundant sources in coal chemical or petroleum refining processes. Furthermore, the co-production coupling of the disclosed technology and MMA products with existing traditional processes such as coal-to-syngas, coal-to-methanol / formaldehyde, and coal-to-ethylene glycol will realize resource sharing and empowering integration, possessing extremely significant industrial implications.

[0008] Another feature of interest discovered in this application is that the coal-based process route has almost the opposite process manufacturing and cost structure characteristics compared to the traditional petrochemical route. For example, in the petrochemical C3 industry structure, acrylic acid is usually produced first and then esterified into acrylate, while this process technology prioritizes the low-cost production of acrylate, and then prepares it via the hydrolysis of acrylate when acrylic acid is needed; similarly, in the petrochemical route, propylene oxide is first produced and then 1,2-propanediol is produced through hydration and ring-opening, while this process technology prioritizes the production of 1,2-propanediol and then prepares propylene oxide via cyclization.

[0009] This inversion of key features of the process flow and cost structure means an unprecedented opportunity for coal chemical industry and coal-based new materials to reduce costs and increase efficiency, namely, to achieve low-cost reverse manufacturing in a disruptive way. [Summary of the Invention]

[0010] This application has now discovered that, as shown in reaction formula (I), the methyl glycolate type substance represented by structural formula A and formaldehyde undergo addition and elimination reactions under reaction conditions to obtain the enolate intermediate represented by structural formula B; subsequently, B and the reducing agent [H] undergo a selective (hydrogenation) reduction reaction under reaction conditions to obtain the lactate product represented by structural formula C; lactate C undergoes an elimination reaction under reaction conditions to obtain the acrylate represented by structural formula D. The technology disclosed in this invention is a novel process for manufacturing lactic acid (ester) or acrylic acid (ester) and the co-production of both.

[0011] The above-mentioned steps A to B, B to C, and C to D may be performed individually; or preferably, the above two or three steps may be performed continuously in a "one-step" or "one-pot" manner without separating and purifying intermediates.

[0012]

[0013] It is worth noting that the structure of the key enol ester intermediate B in general formula (I) is exemplary, as shown below, and chemically it is its enol isomer B1, keto isomer B2, or a mixture of both.

[0014]

[0015] R1 or R2 is independent of each other and is either hydrogen or an aliphatic or aromatic hydrocarbon group containing 1-24 carbon atoms; preferably, R1 or R2 is hydrogen, methyl, or ethyl.

[0016] [H] is any reducing agent capable of reducing carbon-carbon double bonds (C=C) and / or carbonyl groups (C=O) to the corresponding saturated methyl or methylene (CH2) structures. Preferred are hydrogen, isopropanol, formic acid, formate, silanes, boranes, metal hydrides, or catalytic reducing agents composed of these with metal or non-metal catalysts. The use of so-called chiral reducing agents [H] or asymmetric catalytic hydrogenation techniques will yield chiral lactate C with high optical purity (or high enantiomeric excess), as is well known to those skilled in the art.

[0017] "conditions" refers to at least one of the following: additives, light, heat, microwave, ultrasound, vacuum or pressure, solvents, etc.

[0018] The additive is a catalyst, accelerator, or polymerization inhibitor; based on raw material A, the amount of the additive used is a catalytic amount, an equivalent amount, or an excess amount (0.001-100 equivalents). Preferably, the catalyst or accelerator is a Lewis acid or Lewis base compound; the amount of catalyst or accelerator added is 0.1-1000% of the reactant raw material; preferably 0.1-200%, more preferably 1-100%.

[0019] Preferably, the Lewis acid is hydrochloric acid, sulfuric acid, boric acid, nitric acid, phosphoric acid, sulfonic acid, oxalic acid, organic carboxylic acid, nonmetallic acids or oxides of different valence states, metallic or nonmetallic halides, sulfides, or oxides, zeolite, molecular sieve, diatomaceous earth, or heteropoly acid.

[0020] Preferably, the Lewis base is a metal (hydro)oxide, hydride, alkoxide, alkane, carbonate (hydrogen) salt, sulfate (hydrogen) salt, carboxylate, oxalate, nitrate, phosphate (hydrogen) salt, sulfonate, ammonia, ammonia water, or an organic amine.

[0021] Light refers to the reaction system under light irradiation conditions, with the wavelength range of light being 200-780 nanometers.

[0022] Heat refers to the reaction system being carried out under heating conditions, with reaction temperatures ranging from -25 to 500 degrees Celsius.

[0023] Microwave or ultrasonic refers to a system that uses microwave or ultrasonic generators to radiate a reaction system.

[0024] Pressure refers to the pressure under which the reaction system is carried out, or under a certain degree of vacuum. The pressure of the reaction process can be 0.001-200 atmospheres, preferably 0.01-100 atmospheres.

[0025] The solvent is selected from at least one of substituted or unsubstituted aromatic hydrocarbons, straight-chain or branched aliphatic hydrocarbons, (sulfoxides), amides, ethers, alcohols, esters, ketones, nitriles, carboxylic acids, water, amines, carbonates, ionic liquids, and supercritical carbon dioxide containing 1 to 24 carbons; or the liquid substrate itself acts as a solvent medium.

[0026] In some preferred embodiments of the present invention, the solvent is selected from water, dioxane, acetonitrile, ethanol, butanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, dimethyl sulfone, benzyl sulfoxide, benzyl sulfone, cyclobutane sulfoxide, sulfolane, trichlorosilane, dichloromethane, dichloroethane, dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, chloroform, carbon tetrachloride, benzene, toluene, xylene, trimethylbenzene, tetramethylbenzene, acetonitrile, ethylbenzene, diethylbenzene, chlorobenzene, dichlorosilane, etc. At least one of benzene, anisole, nitrobenzene, heptane, hexane, petroleum ether, tetrahydrofuran, methyltetrahydrofuran, methyl tert-butyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, propylene glycol methyl ether acetate, triethylamine, tributylamine, dimethylisopropylamine, pyridine, N,N-tetramethylethylenediamine, N-alkylmorpholine, N-alkylpyrrole, N,N-dimethylformamide, formylmorpholine, N,N-diethylformamide, and N-methylpyrrolidone.

[0027] The use of solvents is preferred but not essential. Under certain conditions, solvents can be omitted, i.e., using the dissolved or melted form of the reactants, or directly mixing the reactants and then reacting under heating, grinding, or gas-phase conditions; and using supercritical carbon dioxide as the reaction medium. The advantages of using supercritical carbon dioxide as the reaction medium are that it is environmentally friendly and facilitates the occurrence of the reaction and the separation of products, advantages well known to professionals in this field.

[0028] Preferably, one way of performing reaction (I) is as shown in reaction (IA), whereby the methyl glycolate type substance represented by structural formula A and methanol are directly methylated under reaction conditions to obtain the lactate product represented by structural formula C; the lactate C undergoes an elimination reaction under reaction conditions to obtain the acrylate represented by structural formula D.

[0029] In this process, methanol itself acts as both a substrate and a hydrogen source, directly completing the methylation. This is a simpler and novel process for producing lactic acid (ester) or acrylic acid (ester) and their co-production. Here, Cat is a metal complex catalyst that can both dehydrogenate methanol to prepare formaldehyde condensation intermediate B and reuse the "temporarily borrowed hydrogen" in situ for the reduction of B to prepare lactic acid ester C. A preferred Cat catalyst is the metal Ir complex [Ir(COD)Cl]2.

[0030] The process technology shown in reaction formula (IA) is a simpler and more efficient new process for manufacturing lactic acid (ester) or acrylic acid (ester) and the co-production of both.

[0031]

[0032] We also found that, as shown in reaction (II), the methyl glycolate type substance represented by structural formula A and formaldehyde undergo addition and elimination reactions under reaction conditions to obtain the enol ester intermediate represented by structural formula B; subsequently, B and the reducing agent [H] undergo a deep hydrogenation reduction reaction under reaction conditions to obtain the 1,2-propanediol product represented by structural formula E; propylene glycol E undergoes an epoxidation reaction under reaction conditions to obtain propylene oxide.

[0033] The technology disclosed in this invention is a new process for manufacturing propylene glycol or propylene oxide and the co-production of the two.

[0034]

[0035] We further discovered that, as shown in reaction (III), the lactate-type substance represented by structural formula C and the methylating agent [Me] undergo methylation under the reaction conditions to obtain the isobutyrate-type intermediate represented by structural formula F; subsequently, the elimination of R2OH from this intermediate yields the methacrylate (ester) product represented by structural formula G.

[0036]

[0037] [Me] is any methylating agent that can provide a methyl functional group; preferred [Me] is a halomethane (chloromethane, bromomethane, iodomethane, fluoromethane, methanesulfonate), N,N-dimethylformamide dimethyl acetal, dimethyl carbonate, dimethyl sulfate, methanol, formaldehyde, dimethyl ether, dimethoxymethane, triethyl orthoformate, or trimethyl orthoacetate.

[0038] Methyl glycolate type feedstock A can be conveniently prepared by selective hydrogenation reduction of DMO via the so-called coal-to-syngas-oxalate DMO route; or by carbonylation of methyl acetal obtained from methanol-formaldehyde. Both are known and mature technologies, and both directly use the cheapest and most readily available C1 type feedstock.

[0039]

[0040] Given the abundant coal chemical sources of C1 raw materials involved, and the co-production coupling between the disclosed technology of this invention and existing traditional processes such as coal-to-syngas, coal-to-methanol / formaldehyde, and coal-to-ethylene glycol, it will practice resource sharing and empowerment integration, which has significant industrial promotion significance for the transformation and upgrading of modern coal chemical industry.

[0041] This application also claims the use of substances prepared by the process technology first disclosed in this invention, namely enolate B, lactate C, 1,2-propanediol E, and / or isobutyrate F, as raw materials or synthons in the preparation of other organic chemicals.

[0042] This application also further claims rights to a coal chemical and coal-based new material technology solution that produces, alone or in combination with, any two or more of the following products: lactic acid (ester) C, acrylate (ester) D, 1,2-propanediol E, propylene oxide, and / or methacrylate (ester) G via the process technology first disclosed in this invention.

[0043] Preferably, one embodiment of the general formula (I) is (I-1), which involves using methyl methyl glycolate A as a raw material, undergoing formaldehyde condensation and catalytic hydrogenation sequentially to prepare methyl methyl lactate C; C then undergoes a methanol elimination reaction to prepare methyl acrylate D.

[0044]

[0045] Preferably, another embodiment of reaction formula (I) is (I-2), which involves using methyl glycolate A as a raw material to sequentially undergo formaldehyde condensation and catalytic hydrogenation to prepare methyl lactate C; C then undergoes a water elimination reaction to prepare methyl acrylate D.

[0046]

[0047] Preferably, another embodiment of the general reaction formula (IA) is (IA-1), which involves the direct methylation reaction of methyl glycolate A and methanol under the action of a catalyst to obtain lactate C; subsequently, C undergoes an R2OH elimination reaction to prepare methyl acrylate D (R2 is preferably methyl or hydrogen):

[0048]

[0049] Preferably, another way of performing the general formula (II) is (II-1), that is, using methyl glycolate A as a raw material, condensing and catalytically hydrogenating it with formaldehyde to obtain propylene glycol E, and then E undergoes an epoxidation reaction to obtain propylene oxide (R2 is preferably methyl or hydrogen).

[0050]

[0051] Preferably, another way of performing the reaction formula (III) is (III-1), that is, the lactate ester type substance shown in structural formula C and the methylating agent [Me] undergo methylation under the reaction conditions to obtain the intermediate shown in structural formula F; then the intermediate eliminates R2OH to prepare the methacrylate (ester) product shown in structural formula G (R2 is preferably methyl or hydrogen, and [Me] is preferably chloromethane, bromomethane, or dimethyl carbonate).

[0052]

[0053] We will explain further in the embodiments.

Detailed Implementation Methods

[0054] The essence of the invention is further illustrated below with reference to specific embodiments:

[0055] Example:

[0056]

[0057] Under nitrogen protection at room temperature, 4.2 g of triethylamine and 7.6 g of solid formaldehyde were placed in 100 mL of dry tetrahydrofuran. 20.2 g of methyl methyl glycolate was added dropwise to the system under rapid mechanical stirring and reflux, and the reaction was stirred for 5 hours. The mixture was cooled to room temperature and concentrated under reduced pressure. The residue was diluted with 10 mL of ethyl acetate and eluted with hexane-ethyl acetate on silica gel column chromatography to give 19.6 g of methyl methoxyacrylate.

[0058] In a pressure-resistant bottle, 19.6 g of methyl methoxyacrylate and 1.6 g of Pd / C hydrogenation catalyst were placed in 120 mL of anhydrous and oxygen-free freshly distilled methanol. The system was purged with hydrogen three times and then stirred thoroughly at 2 atm for 3 hours. The mixture was rapidly filtered through diatomaceous earth, and the supernatant was concentrated and eluted with hexane-ethyl acetate on silica gel column chromatography to obtain 19.1 g of methyl methyl lactate.

[0059] The methyl lactate intermediate prepared above was subjected to thermal elimination of methanol in a fixed-bed reactor packed with CuO / ZSM-22 molecular sieve catalyst (contact time 5 hours) under gas phase feed at 380 degrees Celsius, yielding methyl acrylate product with a conversion rate of 98% and a yield of 90%.

[0060] Example:

[0061]

[0062] Under nitrogen protection at room temperature, 3.3 g of sodium methoxide and 7.4 g of solid formaldehyde were placed in 100 mL of dry methanol. 18.4 g of methyl glycolate was added dropwise to the system under rapid mechanical stirring and reflux, and the reaction was stirred for 5 hours. After cooling the mixture to room temperature, it was neutralized and quenched with sulfuric acid, concentrated under reduced pressure, and the residue was eluted with hexane-ethyl acetate on silica gel column chromatography to give 15.4 g of methyl pyruvate.

[0063] In a pressure vessel, 15.4 g of methyl pyruvate and 0.8 g of Ru(BINAP)(OAc)2 type hydrogenation Noyori catalyst were mixed in 120 mL of anhydrous and oxygen-free freshly distilled methanol. The system was purged with hydrogen three times and then hydrogenated under a hydrogen pressure of 30 atm for 5 hours with thorough stirring. The mixture was rapidly filtered through diatomaceous earth, and the supernatant was concentrated and eluted with hexane-ethyl acetate on silica gel column chromatography to obtain 14.6 g of lactic acid.

[0064] The lactic acid obtained above was prepared into a 46% concentration aqueous solution, which was introduced into a 260°C vaporization chamber at a rate of 9 mL / h, and then dehydrated at 300°C on a 20% Li-type montmorillonite catalyst to obtain methyl acrylate product with a conversion rate of 95% and a yield of 89%.

[0065] Example:

[0066]

[0067] 9.8 g of methyl glycolate, 0.6 g of [Ir(COD)Cl]2 catalyst, and 1.0 g of triphenylphosphine were placed in dry methanol under an oxygen atmosphere, and 10.6 g of KOH powder was added. The mixture was stirred thoroughly at 65°C for 48 hours. After cooling to room temperature, the mixture was concentrated under reduced pressure. The residue was eluted with hexane-ethyl acetate on silica gel column chromatography to give 7.4 g of methyl lactate.

[0068] The methyl lactate intermediate prepared above was subjected to thermal elimination of methanol in a fixed-bed reactor packed with CuO / ZSM-22 molecular sieve catalyst (contact time 5 hours) under gas phase feed at 380 degrees Celsius, yielding methyl acrylate product with a conversion rate of 96% and a yield of 90%.

[0069] Example:

[0070]

[0071] Methyl pyruvate was prepared by condensation of methyl glycolate and formaldehyde, referring to Example 2.

[0072] Under nitrogen protection, 6.5 g of methyl pyruvate was placed in 100 mL of freshly distilled tetrahydrofuran. The solution was cooled to -20°C, and then 60 mL of 2.5 M lithium aluminum hydride solution was slowly added dropwise. After the addition was complete, the solution was gradually brought back to room temperature, and the reaction was quenched with saturated ammonium chloride solution. The mixture was filtered through diatomaceous earth, and the filter cake was washed with tetrahydrofuran. The organic phases were combined and concentrated to dryness. The residue was eluted with hexane-ethyl acetate on silica gel column chromatography to give 3.8 g of 1,2-propanediol.

[0073] 1,2-propanediol was heated at atmospheric pressure and 400 degrees Celsius for 2.8 hours. -1 Propylene oxide was prepared by passing space velocity through a fixed-bed reactor packed with 2.6 g of silica-supported potassium oxide catalyst (K2O loading 14.8%) with a conversion of 59.3% and a selectivity of 69.5%.

[0074] Example:

[0075]

[0076] Methyl methoxyacrylate was prepared by condensation of methyl methyl glycolate and formaldehyde, referring to Example 1.

[0077] Under nitrogen protection, 7.6 g of methyl methoxyacrylate was placed in 100 mL of freshly distilled tetrahydrofuran. The solution was cooled to -20°C, and then 56 mL of 2.5 M lithium aluminum hydride solution was slowly added dropwise. After the addition was complete, the mixture was gradually brought back to room temperature, and the reaction was quenched with saturated ammonium chloride solution. The mixture was filtered through diatomaceous earth, and the filter cake was washed with tetrahydrofuran. The organic phases were combined and concentrated to dryness. The residue was eluted with hexane-ethyl acetate on silica gel column chromatography to give 4.1 g of methyl 1,2-propanediol.

[0078] Under nitrogen protection, 4.1 g of methyl 1,2-propanediol and 0.4 g of potassium hydride powder were placed in 60 mL of dry toluene solvent. The temperature of the mixture was gradually raised to 50-60 degrees Celsius under rapid stirring, and 1.7 g of propylene oxide distillate was collected using a cold trap.

[0079] Example:

[0080]

[0081] Under nitrogen protection, 8.7 g of methyl methyl lactate, 100 mL of dry dimethyl carbonate, and 8.6 g of sodium tert-butoxide were added sequentially to a pressure vessel. The system was refluxed overnight and then cooled to room temperature. The system was adjusted to neutral with sulfuric acid, and the dimethyl carbonate was recovered by distillation. The mixture was concentrated to dryness, and the residue was eluted with petroleum ether-ethyl acetate on silica gel column chromatography to give 7.4 g of methyl methoxyisobutyrate intermediate.

[0082] The methyl methoxyisobutyrate intermediate prepared above was thermally decomposed to remove methanol under the conditions of Example 3 to obtain the methyl methacrylate product.

[0083] It should be emphasized that the above embodiments are merely exemplary and not limiting. Based on the disclosure of this application, any adjustments or changes to the reaction conditions or parameters that a person skilled in the art might normally adopt will not deviate from the spirit of the invention. The scope of protection of this patent shall be determined by the relevant claims.

Claims

1. A novel preparation process for lactic acid (ester) and / or acrylic acid (ester), as shown in reaction formula (I), wherein a methyl glycolate-type substance of structural formula A and formaldehyde undergo addition and elimination reactions under reaction conditions to obtain an enolate intermediate of structural formula B; subsequently, B and a reducing agent [H] undergo a selective (hydrogenation) reduction reaction under reaction conditions to obtain a lactate product of structural formula C; lactate C undergoes an R2OH elimination reaction under reaction conditions to obtain an acrylate of structural formula D. The above steps A to B, B to C, and C to D may be performed individually; or preferably, the above two or three steps are performed continuously in a "one-step" or "one-pot" manner without separating and purifying the intermediates (the same applies below). The technology disclosed in this invention can be used to manufacture lactic acid (ester) C or acrylate (ester) D separately, or preferably, for the co-production of both. R1 or R2 are independently hydrogen or aliphatic or aromatic hydrocarbon groups containing 1-24 carbon atoms; preferably, R1 or R2 is hydrogen, methyl, or ethyl. [H] is any reducing agent capable of reducing carbon-carbon double bonds (C=C) and / or carbonyl groups (C=O) to the corresponding methyl or methylene (CH2) saturated structures. Preferably, it is hydrogen, isopropanol, formic acid, formate, silane, borane, metal hydrides, or a catalytic reduction agent system composed of them and metal or nonmetal catalysts. "Conditions" refers to at least one of the following: additives, light, heat, microwave, ultrasound, vacuum or pressure, solvents, etc. The additive is a catalyst, promoter, or polymerization inhibitor; preferably, the catalyst or promoter is a Lewis acid or Lewis base compound.

2. According to claim (1), based on raw material A, the amount of additive used is a catalytic amount, an equivalent amount, or an excess amount (0.001-100 equivalents). Preferred Lewis acids are hydrochloric acid, sulfuric acid, boric acid, nitric acid, phosphoric acid, sulfonic acid, oxalic acid, organic carboxylic acids, nonmetallic acids or oxides of different valence states, metallic or nonmetallic halides, sulfides, or oxides, zeolites, molecular sieves, diatomaceous earth, or heteropoly acids. Preferred Lewis bases are metal (hydro)oxides, hydrides, alkoxides, alkylamines, metal (hydrocarbonate), (hydrosulfate), carboxylates, oxalates, nitrates, (hydrophosphate), sulfonates, ammonia, ammonia water, or organic amines.

3. According to claim (1), light refers to the reaction system being carried out under light irradiation conditions, with a wavelength range of 200-780 nanometers. Heat refers to the reaction system being carried out under heating conditions, with a reaction temperature of -25-500 degrees Celsius. Microwave or ultrasonic refers to irradiating the reaction system using a microwave or ultrasonic generator. Pressure refers to the reaction system being carried out under pressure or a certain vacuum condition, with a reaction process pressure of 0.001-200 atmospheres, preferably 0.01-100 atmospheres. The solvent is selected from at least one of substituted or unsubstituted aromatic hydrocarbons, straight-chain or branched aliphatic hydrocarbons, (sulfoxide) sulfones, amides, ethers, alcohols, esters, ketones, nitriles, carboxylic acids, water, amines, carbonates, ionic liquids, and supercritical carbon dioxide containing 1-24 carbon atoms; or the liquid substrate itself simultaneously acts as a solvent medium.

4. According to claim (1), a preferred embodiment of reaction (I) is as shown in reaction (IA), where the methyl glycolate type substance represented by structural formula A, methanol, and the catalyst Cat directly undergo methylation under reaction conditions to obtain the lactate product represented by structural formula C; the lactate C then undergoes an R2OH elimination reaction under reaction conditions to obtain the acrylate represented by structural formula D. A preferred Cat catalyst is a metal Ir complex [Ir(COD)Cl]2:

5. A novel process for preparing 1,2-propanediol and / or propylene oxide, as shown in reaction formula (II), wherein a methyl glycolate-type substance represented by structural formula A and formaldehyde undergo addition and elimination reactions under reaction conditions to obtain an enolate intermediate represented by structural formula B; subsequently, B and a reducing agent [H] undergo a deep hydrogenation reduction reaction under reaction conditions to obtain the 1,2-propanediol product represented by structural formula E; propylene glycol E undergoes an epoxidation reaction under reaction conditions to obtain propylene oxide. The technology disclosed in this invention can be used to manufacture 1,2-propanediol E or propylene oxide alone, or preferably, for the co-production of both.

6. A novel preparation process for a methacrylate substance, as shown in reaction formula (III), wherein the lactate ester substance represented by structural formula C and the methylating agent [Me] undergo methylation under reaction conditions to obtain the isobutyrate ester intermediate represented by structural formula F; subsequently, the intermediate is subjected to the elimination of R2OH to prepare the methacrylate (ester) represented by structural formula G: [Me] is any methylating agent that can provide a methyl functional group; preferred [Me] is a halomethane (chloromethane, bromomethane, iodomethane, fluoromethane, methanesulfonate), N,N-dimethylformamide dimethyl acetal, dimethyl carbonate, dimethyl sulfate, methanol, formaldehyde, dimethyl ether, dimethoxymethane, triethyl orthoformate, or trimethyl orthoacetate.

7. The use of a substance prepared by the process technology disclosed in this invention, namely enolate B, lactate C, 1,2-propanediol E, and / or isobutyrate F, as a raw material or synthon in the preparation of other organic chemicals, according to claims (1-6).

8. According to claims (1-6), a coal chemical and coal-based new material technology solution for producing, alone or in combination with, any two or more of the following products: lactic acid (ester) C, acrylate (ester) D, 1,2-propanediol E, propylene oxide, and / or methacrylate (ester) G, via the process technology disclosed in this invention.

9. According to claim (1), a preferred embodiment of the general reaction formula (I) is (I-1), namely, methyl methyl glycolate A is used as a raw material to prepare methyl methyl lactate C by successively undergoing formaldehyde condensation and catalytic hydrogenation; C then undergoes a methanol elimination reaction to prepare methyl acrylate D:

10. According to claim (1), a preferred embodiment of the general reaction formula (I) is (I-2), namely, methyl glycolate A is used as a raw material to prepare methyl lactate C by sequentially undergoing formaldehyde condensation and catalytic hydrogenation; C then undergoes a water elimination reaction to prepare methyl acrylate D:

11. According to claim (4), another preferred embodiment of the general reaction formula (IA) is (IA-1), that is, methyl glycolate A and methanol are directly subjected to a methylation reaction under the action of a catalyst to obtain lactate C; then C undergoes an R2OH elimination reaction to prepare methyl acrylate D (R2 is preferably methyl or hydrogen):

12. According to claim (5), a preferred embodiment of the general reaction formula (II) is (II-1), namely, condensation and catalytic hydrogenation of methyl glycolate A with formaldehyde to obtain propylene glycol E, followed by epoxidation of E to obtain propylene oxide (R2 is preferably methyl or hydrogen):

13. According to claim (6), a preferred embodiment of the reaction formula (III) is (III-1), namely, methylation of the lactate ester type substance represented by structural formula C and the methylating agent [Me] under reaction conditions to obtain the intermediate represented by structural formula F; subsequently, the intermediate is subjected to the elimination of R2OH to prepare the methacrylate product represented by structural formula G (R2 is preferably methyl or hydrogen): [Me] is any methylating agent that can provide a methyl functional group; preferably, [Me] is a halomethane (chloromethane, bromomethane, iodomethane, fluoromethane, methanesulfonate), N,N-dimethylformamide dimethyl acetal, dimethyl carbonate, dimethyl sulfate, methanol, formaldehyde, dimethyl ether, dimethoxymethane, triethyl orthoformate, or trimethyl orthoacetate. R2 is preferably methyl or hydrogen, and [Me] is preferably chloromethane, bromomethane, or dimethyl carbonate.

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