Alkaline earth metal oxide and alkoxy concerted catalysis carbonic ester direct preparation process

Abstract

The present invention relates to the field of new material chemicals, and discloses for the first time a new process for the direct preparation of symmetric carbonates from alcohols or phenols and carbon dioxide using alkaline earth metal oxides and hydrocarbyloxy species in synergy as catalysts. Carbonic ester is a green chemical raw material with excellent environmental protection performance and wide application. The catalyst and reactants used in the method are large-scale industrial products, and the cost is low.

Description

[Technical field]

[0001] The present invention relates to the field of new material chemicals, and in particular to a new method technology for directly preparing symmetrical carbonates from alcohols or phenols and carbon dioxide using alkaline earth metal oxides and alkoxy substances as catalysts at the same time. The catalysts and reactants used are large-scale industrial products, which are easy to obtain and low in cost. This ensures the efficient and low-cost manufacturing of the carbonate products. [Background technology]

[0002] Carbonate is a green chemical raw material with excellent environmental performance and wide application. It can be used in resins, paints, solvents for nitrocellulose, electrolytes for new energy batteries, and intermediates for drug synthesis. With the continuous development of carbonate technology in recent years, derivative products have become more and more abundant. In particular, with the growing demand for green coatings and new energy battery systems, the production capacity of carbonate compounds has been rapidly expanded. New low-cost non-toxic production process technology is a major technical project that the industry has been persistently researching.

[0003] The traditional process for preparing symmetrical carbonates is the direct condensation of alcohols with highly toxic phosgene; the current mainstream process is to prepare them by transesterification of ethylene carbonate with different alcohols; the above process is harsh and has poor selectivity. The preparation of carbonates by direct esterification and dehydration of alcohols and carbon dioxide is a very challenging technical route. Currently, it is necessary to add catalysts that are not common in the market and harsh reaction conditions (Energies 2022,15,5133). However, the catalyst is prone to deactivation and failure, and the conversion rate and product yield are not high, making it difficult to achieve industrialization.

[0004] In our previous application, we have disclosed that the use of easily available metal alkoxides (such as magnesium methoxide) as raw materials can be directly converted into corresponding carbonate products with high yield under the action of carbon dioxide (patent application number: 202310394252.6). In this process, the main cost lies in the metal alkoxide.

[0005] The gist of our application is that we continue to explore and unexpectedly discover that the use of cheaper alkaline earth metal oxides (such as magnesium oxide) can catalyze the direct esterification and dehydration of alcohols or phenols with carbon dioxide to prepare symmetrical carbonates in high yields with only a catalytic equivalent and key reaction conditions. This makes the process very competitive in terms of low cost. [Summary of the invention]

[0006] The present application has now unexpectedly found that, as shown in reaction formula (I), in the presence of calcium carbide (CaC2), catalyst alkaline earth metal oxide MO, and catalyst alkoxy donor RO-Y, alcohol or phenol ROH and CO2 can directly and very efficiently generate symmetrical carbonate A and acetylene C2H2. The byproduct of the reaction of ROH and CO2 is water, which then reacts irreversibly with calcium carbide to produce acetylene, thereby greatly promoting the balance of the overall reaction to proceed in the positive direction. In addition, it is widely known to the technical personnel in the industry that when the amount of the reactant alcohol or phenol is equal to or greater than the calcium carbide raw material, the excess alcohol or phenol can also react with calcium carbide at high temperature to generate the byproduct acetylene. Thereby, relying on the technology disclosed in the present invention, the co-production of symmetrical carbonate and acetylene gas can be further achieved.

[0007]

[0008] Wherein, R is a branched or straight chain aliphatic (hetero) hydrocarbon group containing 1 to 24 carbon atoms, or a (hetero) aromatic hydrocarbon group containing 4 to 24 carbon atoms. The constraint is that the R groups in RO-Y and ROH are the same. Preferably, R is methyl, ethyl, propyl, butyl, allyl, benzyl, phenyl, naphthyl, hexadecyl, or oligoethylene glycol.

[0009] Y is a monovalent alkali metal, a divalent alkaline earth metal, or other organic compound group that can dissociate from the RO group. The constraint is that the catalyst RO-Y can release the hydrocarbon oxygen anion RO — Preferably, based on the molar amount of calcium carbide, the amount of RO-Y used is 0.03 equivalent to 0.5 equivalent; the preferred chemical formula or chemical structure is LiOMe, NaOMe, KOMe, Mg(OMe)2, Ca(OMe)2, LiOEt, NaOEt, KOEt, or the following chemical structure:

[0010]

[0011] Catalyst MO is a divalent alkaline earth metal oxide; preferably MgO, and its usage amount is 0.1 equivalent to 0.5 equivalent based on the molar amount of calcium carbide.

[0012] Conditions is at least one of solvent, temperature, pressure, and additives. Preferably, conditions includes two or three of the above three conditions at the same time.

[0013] The solvent can be the reactant alcohol or phenol ROH itself, or a mixture of one or more of ether, ester, nitrile, aromatic hydrocarbon, carbonate, and supercritical carbon dioxide. Preferably, the alcohol or phenol ROH itself is also used as the solvent.

[0014] The temperature is 20°C-400°C; preferably 150°C-260°C.

[0015] The pressure is the pressure of CO2 gas phase, 1atm-300atm; preferably 30atm-240atm.

[0016] The additive refers to a reaction accelerator, a synergist, a catalyst, an inhibitor, an oxidant, a reducing agent and / or a functional aid. Based on the molar amount of calcium carbide, the amount of the additive used is 0, a catalytic amount, an equivalent amount, or an over equivalent amount (0-100 equivalents).

[0017] Through the technology disclosed in the present invention, the following exemplary but non-limiting symmetrical carbonate compounds can be prepared in high yield:

[0018]

[0019] The gist of the present invention is further explained below with reference to specific embodiments. [Specific implementation method]

[0020] Embodiment 1:

[0021]

[0022] Magnesium oxide (604 mg, 15 mmol), calcium carbide (4.12 g, 45 mmol), sodium methoxide (243 mg, 4.5 mmol), and methanol (60 mL) were added to the autoclave; then the CO2 cylinder was connected for inflating, and the initial pressure was maintained between 5 MPa and 7 MPa; then the autoclave was sealed, the temperature was raised to 190 ° C (pressure was between 13 MPa and 20 MPa), and the reaction was carried out for 5 hours. After cooling and releasing the pressure, sampling was performed and the reaction was monitored by GC; the DMC content was calculated to be 3.57 g (39.6 mmol) based on the internal standard curve of dimethyl carbonate (DMC)-biphenyl; based on the molar amount of calcium carbide, the DMC yield was 88%.

[0023] Embodiment 2:

[0024]

[0025] Magnesium oxide (604 mg, 15 mmol), calcium carbide (4.12 g, 45 mmol), potassium methoxide (316 mg, 4.5 mmol), and methanol (60 mL) were added to the autoclave; then the CO2 cylinder was connected for inflating, and the initial pressure was maintained between 5 MPa and 7 MPa; then the autoclave was sealed, the temperature was raised to 200 ° C (pressure was between 13 MPa and 20 MPa), and the reaction was carried out for 5 hours. After cooling and releasing the pressure, sampling was performed and the reaction was monitored by GC; the DMC content was calculated to be 3.89 g (43.2 mmol) based on the DMC-biphenyl internal standard curve; based on the molar amount of calcium carbide, the DMC yield was 96%.

[0026] Embodiment 3:

[0027]

[0028] Magnesium oxide (604 mg, 15 mmol), calcium carbide (4.12 g, 45 mmol), trimethyl orthoformate (2.39 g, 22.5 mmol), and methanol (60 mL) were added to the autoclave; then the CO2 cylinder was connected for inflating, and the initial pressure was maintained between 5 MPa and 7 MPa; then the autoclave was sealed, the temperature was raised to 210 ° C (pressure was between 13 MPa and 20 MPa), and the reaction was carried out for 5 hours. After cooling and releasing the pressure, sampling was performed and the reaction was monitored by GC; the DMC content was calculated to be 3.81 g (42.3 mmol) based on the DMC-biphenyl internal standard curve; based on the molar amount of calcium carbide, the DMC yield was 94%.

[0029] Embodiment 4:

[0030]

[0031] Magnesium oxide (604 mg, 15 mmol), calcium carbide (4.12 g, 45 mmol), polyoxymethylene (68 mg), and methanol (60 mL) were added to the autoclave; then the CO2 cylinder was connected for inflating, and the initial pressure was maintained between 5 MPa and 7 MPa; then the autoclave was sealed, the temperature was raised to 200 ° C (pressure was between 13 MPa and 20 MPa), and the reaction was carried out for 5 hours. After cooling and releasing the pressure, the sample was taken and the reaction was monitored by GC; the DMC content was calculated to be 3.69 g (41.0 mmol) based on the DMC-biphenyl internal standard curve; based on the molar amount of calcium carbide, the DMC yield was 91%.

[0032] Embodiment 5:

[0033]

[0034] Calcium oxide (841 mg, 15 mmol), calcium carbide (4.12 g, 45 mmol), 8% magnesium methoxide solution (5 g), and methanol (60 mL) were added to the autoclave; then the CO2 cylinder was connected for inflating, and the initial pressure was maintained between 5 MPa and 7 MPa; then the autoclave was sealed, the temperature was raised to 180 ° C (pressure was between 13 MPa and 20 MPa), and the reaction was carried out for 5 hours. After cooling and releasing the pressure, sampling was performed and the reaction was monitored by GC; the DMC content was calculated to be 2.88 g (32.0 mmol) based on the DMC-biphenyl internal standard curve; based on the molar amount of calcium carbide, the DMC yield was 71%.

[0035] Embodiment 6:

[0036]

[0037] Magnesium oxide (604 mg, 15 mmol), calcium carbide (4.12 g, 45 mmol), sodium ethoxide (612 mg, 9 mmol), and ethanol (60 mL) were added to the autoclave; then the CO2 cylinder was connected for inflating, and the initial pressure was maintained between 5 MPa and 7 MPa; then the autoclave was sealed, the temperature was raised to 210 ° C (pressure was between 13 MPa and 20 MPa), and the reaction was carried out for 6 hours. After cooling and releasing the pressure, sampling was performed and the reaction was monitored by GC; the content of DEC was calculated to be 3.99 g (33.8 mmol) based on the internal standard curve of diethyl carbonate (DEC)-biphenyl; the yield of DEC was 75% based on the molar amount of calcium carbide.

[0038] Embodiment 7:

[0039]

[0040] Magnesium oxide (604 mg, 15 mmol), calcium carbide (4.12 g, 45 mmol), diethoxymethane (937 mg, 9 mmol), and ethanol (60 mL) were added to the autoclave; then the CO2 cylinder was connected for inflating, and the initial pressure was maintained between 5 MPa and 7 MPa; then the autoclave was sealed, the temperature was raised to 210 ° C (pressure was between 13 MPa and 20 MPa), and the reaction was carried out for 6 hours. After cooling and releasing the pressure, sampling was performed and the reaction was monitored by GC; the DEC content was calculated to be 3.19 g (30.6 mmol) based on the DEC-biphenyl internal standard curve; based on the molar amount of calcium carbide, the DEC yield was 68%.

[0041] Embodiment 8:

[0042]

[0043] Magnesium oxide (604 mg, 15 mmol), calcium carbide (4.12 g, 45 mmol), triethyl orthoformate (2.22 g, 15 mmol), silicon dioxide (1.35 g, 22.5 mmol), and ethanol (60 mL) were added to the autoclave; then the CO2 cylinder was connected for inflating, and the initial pressure was maintained between 5 MPa and 7 MPa; then the autoclave was sealed, the temperature was raised to 210 ° C (pressure was between 13 MPa and 20 MPa), and the reaction was carried out for 6 hours. After cooling and releasing the pressure, sampling was performed and the reaction was monitored by GC; the DEC content was calculated to be 4.31 g (36.5 mmol) based on the DEC-biphenyl internal standard curve; based on the molar amount of calcium carbide, the DEC yield was 81%.

[0044] It should be emphasized that the above embodiments are merely illustrative and not restrictive. Based on the disclosure of this application, any adjustment or change in reaction conditions or parameters that may be commonly adopted by practitioners will not deviate from the gist of the present invention. The scope of protection of this patent shall be based on the relevant rights record items.

Claims

1. A direct preparation process technology of carbonate esters catalyzed by alkaline earth metal oxides and alkoxy groups, as shown in reaction formula (I), in the presence of calcium carbide CaC2, catalyst alkaline earth metal oxide MO, and catalyst alkoxy donor RO-Y, alcohol or phenol ROH and carbon dioxide CO2 can directly and highly efficiently generate symmetrical carbonate ester A and acetylene C2H2. in, R is a branched or straight chain aliphatic (hetero) hydrocarbon group containing 1 to 24 carbon atoms, or a (hetero) aromatic hydrocarbon group containing 4 to 24 carbon atoms, with the constraint that the R groups in RO-Y and ROH are the same. Y is a monovalent alkali metal, a divalent alkaline earth metal, or other organic compound group that can dissociate from the RO group. The constraint is that the catalyst RO-Y can release the hydrocarbon oxygen anion RO — . The conditions are at least one of solvent, temperature, pressure, and additives.

2. According to claim 1, the solvent can be the reactant alcohol or phenol ROH itself, or a mixture of one or more of ether, ester, nitrile, aromatic hydrocarbon, carbonate, and supercritical carbon dioxide. The temperature is 20°C-400°C. The pressure is 1atm-300atm of the CO2 gas phase. The additive refers to a reaction accelerator, a synergist, a catalyst, an inhibitor, an oxidant, a reducing agent and / or a functional aid. Based on the molar amount of calcium carbide, the amount of the additive used is 0, a catalytic amount, an equivalent amount, or an over equivalent amount (0-100 equivalents).

3. According to claim 1, the following exemplary but non-limiting symmetrical carbonate compounds can be prepared by the process disclosed in the present invention:

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