阅读说明：本技术 用于制备碳酸二甲酯的方法 (Method for producing dimethyl carbonate ) 是由 戈军伟 何文军 王意 于 2019-09-24 设计创作，主要内容包括：本发明提供了一种硅化镁和/或碳化锂在酯交换反应特别是在制备碳酸二甲酯的反应中作为催化剂的用途。本发明还提供了一种用于制备碳酸二甲酯的方法,其包括将碳酸亚烷基酯和甲醇与催化剂接触,其中催化剂包括硅化镁和/或碳化锂。本发明提供的方法采用硅化镁和/或碳化锂催化剂,解决了以往技术中在酯交换反应中存在的非均相催化剂活性低及活性组分易流失的问题。本发明的催化剂用于碳酸亚烷基酯和甲醇的酯交换反应制备碳酸二甲酯中,碳酸亚烷基酯的转化率、选择性均较高。(The invention provides the use of magnesium silicide and/or lithium carbide as a catalyst in transesterification reactions, in particular in the reaction for preparing dimethyl carbonate. The invention also provides a process for the preparation of dimethyl carbonate comprising contacting alkylene carbonate and methanol with a catalyst, wherein the catalyst comprises magnesium silicide and/or lithium carbide. The method provided by the invention adopts the magnesium silicide and/or lithium carbide catalyst, and solves the problems of low activity of heterogeneous catalysts and easy loss of active components in the ester exchange reaction in the prior art. The catalyst of the invention is used for preparing dimethyl carbonate by the ester exchange reaction of alkylene carbonate and methanol, and the conversion rate and the selectivity of the alkylene carbonate are both higher.)

1. Use of magnesium silicide and/or lithium carbide as a catalyst in transesterification reactions.

2. Use of magnesium silicide and/or lithium carbide as a catalyst in a reaction for the preparation of dimethyl carbonate.

3. A process for the preparation of dimethyl carbonate comprising contacting alkylene carbonate and methanol with a catalyst, wherein the catalyst comprises magnesium silicide and/or lithium carbide.

4. The method of claim 3, wherein the contacting temperature is 40-160 ℃.

5. The method of claim 3 or 4, wherein the temperature of the contacting is 50-140 ℃.

6. A process according to any one of claims 3 to 5, characterized in that the molar ratio of methanol to alkylene carbonate is from 2 to 20: 1.

7. a process according to any one of claims 3 to 6, characterized in that the molar ratio of methanol to alkylene carbonate is from 4 to 15: 1.

8. a process according to any one of claims 3 to 7, characterized in that the weight ratio of catalyst to alkylene carbonate is from 0.001 to 0.5: 1.

9. a process according to any one of claims 3 to 7, characterized in that the weight ratio of catalyst to alkylene carbonate is from 0.002 to 0.2: 1.

10. A process according to any one of claims 3 to 8, characterized in that the alkylene carbonate comprises at least one selected from C2-C12 alkylene carbonates, preferably at least one selected from ethylene carbonate and propylene carbonate.

Technical Field

The invention relates to a method for preparing dimethyl carbonate by transesterification of alkylene carbonate and methanol.

Background

Dimethyl carbonate (DMC) is active in chemical property, excellent in physical property, non-toxic and easy to biodegrade, is a novel low-pollution environment-friendly green basic chemical raw material, can be used as a solvent, a gasoline additive, a lithium ion battery electrolyte and a carbonylation, methylation and carbonylmethoxylation reagent, is widely applied to the field of chemical industry, and is actively researched in various countries at present in a green chemical process based on DMC, the environment-friendly chemical raw material. Wherein the ester exchange method is superior to the method with mild reaction conditions and high yield, and the co-production of ethylene glycol or propylene glycol becomes a method with great industrial prospects.

In general, an alkali metal hydroxide, an alkali metal carbonate, an alkali metal alcohol, and the like (f.risse et al, US2011040117, c.p. alais et al, WO2010063780) are often used as a catalyst in the transesterification reaction, but since they are homogeneous catalysts, they are not easily separated from the product, and are difficult to reuse. Commonly used heterogeneous catalysts include alkali or alkali metal salts, metal oxide catalysts, alkali (earth) metal exchanged zeolite or clay materials and ion exchange resins, etc. supported on a carrier. Alkali metal or alkali metal salt supported on carrier, e.g. KF/Al₂O₃NaOH/Chitosan and Cs₂CO₃/SiO₂-Al₂O₃Etc. (H.ZHang, CN 101249452; Y.ZHao, CN 101121147; C.D.Chang et al, WO0156971A1) which have the disadvantage of being susceptible to water and CO in the air₂Such that activity is reduced; metal oxide catalysts, e.g. Al₂O₃MgO and the like (B.M.Bhanage, et al.appl.Catal.A 219(2001) 259-266; J.S.Buchanan et al, US 2005080287; Z.Z.Jiang et al, US6207850), and alkali (earth) metal exchanged zeolite or clay materials such as Cs-ZSM-5, Mg-smitite and the like (C.D.Chang et al, WO 0073256; B.M.Bhanage et al.Cat.83 (2002)137-141), which have the disadvantage that the activity or selectivity is generally relatively low; separation deviceAnd a resin such as quaternary ammonium type or tertiary amine type resin (J.F. Knifton et al, J.mol. Cat. A67 (1991) 389-.

Disclosure of Invention

The invention aims to provide a novel catalyst for preparing dimethyl carbonate by transesterification of alkylene carbonate and methanol, which has the characteristics of high activity and selectivity and difficult loss of active components.

In a first aspect, the present invention provides the use of magnesium silicide and/or lithium carbide as a catalyst in a transesterification reaction.

In a second aspect, the present invention provides the use of magnesium silicide and/or lithium carbide as a catalyst in a reaction to produce dimethyl carbonate.

In a third aspect, the present invention provides a process for the preparation of dimethyl carbonate comprising contacting alkylene carbonate and methanol with a catalyst, wherein the catalyst comprises magnesium silicide and/or lithium carbide.

According to some embodiments of the invention, the temperature of the contacting is 40-160 ℃.

According to a preferred embodiment of the invention, the temperature of said contacting is between 50 and 140 ℃.

According to some embodiments of the invention, the contacting is for a time of 0.1 to 30 hours.

According to some embodiments of the invention, the contacting is for a period of 1 to 10 hours.

According to some embodiments of the invention, the molar ratio of methanol to alkylene carbonate is from 2 to 20: 1.

according to a preferred embodiment of the invention, the molar ratio of methanol to alkylene carbonate is from 4 to 15: 1.

according to some embodiments of the invention, the weight ratio of the catalyst to alkylene carbonate is from 0.001 to 0.5: 1.

according to a preferred embodiment of the invention, the weight ratio of the catalyst to alkylene carbonate is from 0.002 to 0.2: 1.

According to some embodiments of the invention, the alkylene carbonate comprises at least one selected from the group consisting of C2-C12 alkylene carbonates.

According to a preferred embodiment of the present invention, the alkylene carbonate is selected from at least one of ethylene carbonate and propylene carbonate.

The method of the invention adopts the magnesium silicide and/or lithium carbide catalyst, solves the problem of low activity of heterogeneous catalyst in the ester exchange reaction in the prior art; in addition, the catalyst has stable properties in a system, the active center is not easy to lose, and the problem that the active component of the heterogeneous catalyst is easy to lose is solved. The catalyst of the invention is used for preparing dimethyl carbonate by the ester exchange reaction of alkylene carbonate and methanol, and the conversion rate and the selectivity of the alkylene carbonate are both higher.

Drawings

Figure 1 is an XRD pattern of the catalyst according to example 1 of the present invention.

Detailed Description

The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention in any way.

[ example 1 ]

22.0 g of ethylene carbonate, 32.0 g of methanol and 0.22 g of magnesium silicide as a catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate: 4: 1, weight ratio of catalyst to ethylene carbonate: 0.01: 1) and reacted at 120 ℃ for 2 hours. After the reaction was complete, the autoclave was cooled to room temperature and vented. And (3) taking the liquid-phase product for gas chromatography analysis, wherein the conversion rate of the ethylene carbonate is 62.5%, the selectivity of the dimethyl carbonate is 99.8%, and the selectivity of the ethylene glycol is 99.8%.

[ example 2 ]

22.0 g of ethylene carbonate, 32.0 g of methanol and 0.22 g of magnesium silicide as a catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate: 4: 1, weight ratio of catalyst to ethylene carbonate: 0.01: 1) and reacted at 100 ℃ for 4 hours. After the reaction was complete, the autoclave was cooled to room temperature and vented. And (3) performing gas chromatography analysis on the liquid-phase product to obtain the ethylene carbonate with the conversion rate of 62.3%, the selectivity of dimethyl carbonate of 99.8% and the selectivity of ethylene glycol of 99.8%.

[ example 3 ]

11.0 g of ethylene carbonate, 32.0 g of methanol and 0.55 g of magnesium silicide catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate: 8: 1, weight ratio of catalyst to ethylene carbonate: 0.05: 1) and reacted at 120 ℃ for 2 hours. After the reaction was complete, the autoclave was cooled to room temperature and vented. And (3) taking the liquid-phase product for gas chromatography analysis, wherein the conversion rate of the ethylene carbonate is 80.6%, the selectivity of dimethyl carbonate is 99.9%, and the selectivity of ethylene glycol is 99.8%.

[ example 4 ]

22.0 g of ethylene carbonate, 64.0 g of methanol and 0.55 g of magnesium silicide catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate: 8: 1, weight ratio of catalyst to ethylene carbonate: 0.005: 1) and reacted at 120 ℃ for 4 hours. After the reaction was complete, the autoclave was cooled to room temperature and vented. And (3) taking the liquid-phase product for gas chromatography analysis, wherein the conversion rate of the ethylene carbonate is 80.2%, the selectivity of the dimethyl carbonate is 99.9%, and the selectivity of the ethylene glycol is 99.8%.

Comparative example 1

22.0 g of ethylene carbonate, 32.0 g of methanol and 0.22 g of silica catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate: 4: 1, weight ratio of catalyst to ethylene carbonate: 0.01: 1) and reacted at 100 ℃ for 4 hours. After the reaction was complete, the autoclave was cooled to room temperature and vented. And (4) taking the liquid-phase product for gas chromatographic analysis to obtain the ethylene carbonate with the conversion rate of less than 1%.

Comparative example 2

11.0 g of ethylene carbonate, 32.0 g of methanol and 0.55 g of magnesium oxide as a catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate: 8: 1, weight ratio of catalyst to ethylene carbonate: 0.005: 1) and reacted at 120 ℃ for 4 hours. After the reaction was complete, the autoclave was cooled to room temperature and vented. And (3) taking the liquid-phase product for gas chromatography analysis, wherein the conversion rate of the ethylene carbonate is 32.5%, the selectivity of dimethyl carbonate is 99.9%, and the selectivity of ethylene glycol is 99.8%.

[ example 5 ]

22.0 g of ethylene carbonate, 32.0 g of methanol and 0.22 g of lithium carbide as a catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate: 4: 1, weight ratio of catalyst to ethylene carbonate: 0.01: 1) and reacted at 120 ℃ for 2 hours. After the reaction was complete, the autoclave was cooled to room temperature and vented. And (3) taking the liquid-phase product for gas chromatography analysis, wherein the conversion rate of the ethylene carbonate is 61.8%, the selectivity of the dimethyl carbonate is 99.7%, and the selectivity of the ethylene glycol is 99.8%.

[ example 6 ]

22.0 g of ethylene carbonate, 32.0 g of methanol, 0.11 g of magnesium silicide as a catalyst and 0.11 g of lithium carbide as a catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate: 4: 1, weight ratio of catalyst to ethylene carbonate: 0.01: 1) and reacted at 120 ℃ for 2 hours. After the reaction was complete, the autoclave was cooled to room temperature and vented. And (3) taking the liquid-phase product for gas chromatography analysis, wherein the conversion rate of the ethylene carbonate is 61.7%, the selectivity of the dimethyl carbonate is 99.8%, and the selectivity of the ethylene glycol is 99.9%.

[ example 7 ]

22.0 g of ethylene carbonate, 32.0 g of methanol, 0.2 g of magnesium silicide as a catalyst and 0.02 g of lithium carbide as a catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate: 4: 1, weight ratio of catalyst to ethylene carbonate: 0.01: 1) and reacted at 120 ℃ for 2 hours. After the reaction was complete, the autoclave was cooled to room temperature and vented. And (3) taking the liquid-phase product for gas chromatography analysis, wherein the conversion rate of the ethylene carbonate is 61.5%, the selectivity of the dimethyl carbonate is 99.7%, and the selectivity of the ethylene glycol is 99.8%.

[ example 8 ]

22.0 g of ethylene carbonate, 32.0 g of methanol, 0.02 g of magnesium silicide as a catalyst and 0.2 g of lithium carbide as a catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate: 4: 1, weight ratio of catalyst to ethylene carbonate: 0.01: 1) and reacted at 120 ℃ for 2 hours. After the reaction was complete, the autoclave was cooled to room temperature and vented. And (3) taking the liquid-phase product for gas chromatography analysis, wherein the conversion rate of the ethylene carbonate is 61.9%, the selectivity of the dimethyl carbonate is 99.7% and the selectivity of the ethylene glycol is 99.8%.

[ example 9 ]

44 g of ethylene carbonate, 32 g of methanol and 0.44 g of magnesium silicide as a catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate: 2:1, weight ratio of catalyst to ethylene carbonate: 0.01: 1) and reacted at 120 ℃ for 2 hours. After the reaction was complete, the autoclave was cooled to room temperature and vented. And (3) taking the liquid-phase product for gas chromatography analysis, wherein the conversion rate of the ethylene carbonate is 35.4%, the selectivity of dimethyl carbonate is 99.8%, and the selectivity of ethylene glycol is 99.9%.

[ example 10 ]

11 g of ethylene carbonate, 32 g of methanol and 0.11 g of magnesium silicide as a catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate: 8: 1, weight ratio of catalyst to ethylene carbonate: 0.01: 1) and reacted at 120 ℃ for 2 hours. After the reaction was complete, the autoclave was cooled to room temperature and vented. And (3) taking the liquid-phase product for gas chromatography analysis, wherein the conversion rate of the ethylene carbonate is 80.1%, the selectivity of the dimethyl carbonate is 99.8%, and the selectivity of the ethylene glycol is 99.9%.

[ example 10 ]

5.9 g of ethylene carbonate, 32 g of methanol and 0.06 g of magnesium silicide as a catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate: 15: 1, weight ratio of catalyst to ethylene carbonate: 0.01: 1) and reacted at 120 ℃ for 2 hours. After the reaction was complete, the autoclave was cooled to room temperature and vented. And (3) taking the liquid-phase product for gas chromatography analysis, wherein the conversion rate of the ethylene carbonate is 87.8%, the selectivity of the dimethyl carbonate is 99.9%, and the selectivity of the ethylene glycol is 99.9%.

[ example 11 ]

2.75 g of ethylene carbonate, 32 g of methanol and 0.03 g of magnesium silicide as a catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate 0.5: 1, weight ratio of catalyst to ethylene carbonate 0.01: 1) and reacted at 120 ℃ for 2 hours. After the reaction was complete, the autoclave was cooled to room temperature and vented. The liquid phase product was taken for gas chromatography analysis to obtain ethylene carbonate with a conversion of 10.1%, dimethyl carbonate with a selectivity of 82.2% and ethylene glycol with a selectivity of 87.5%.

[ example 12 ]

22 g of ethylene carbonate, 32 g of methanol and 0.002 g of magnesium silicide as a catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate 4: 1, weight ratio of catalyst to ethylene carbonate 0.001: 1) and reacted at 120 ℃ for 2 hours. After the reaction was complete, the autoclave was cooled to room temperature and vented. And (3) taking the liquid-phase product for gas chromatography analysis, wherein the conversion rate of the ethylene carbonate is 61.8%, the selectivity of the dimethyl carbonate is 99.7%, and the selectivity of the ethylene glycol is 99.9%.

[ example 13 ]

22 g of ethylene carbonate, 32 g of methanol and 2.2 g of magnesium silicide as a catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate: 4: 1, weight ratio of catalyst to ethylene carbonate: 0.1: 1) and reacted at 120 ℃ for 2 hours. After the reaction was complete, the autoclave was cooled to room temperature and vented. And (3) taking the liquid-phase product for gas chromatography analysis, and obtaining that the conversion rate of the ethylene carbonate is 61.0 percent, the selectivity of the dimethyl carbonate is 99.9 percent, and the selectivity of the ethylene glycol is 99.9 percent.

[ example 14 ]

22 g of ethylene carbonate, 32 g of methanol and 11 g of magnesium silicide as a catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate 4: 1, weight ratio of catalyst to ethylene carbonate 0.5: 1) and reacted at 120 ℃ for 2 hours. After the reaction was complete, the autoclave was cooled to room temperature and vented. And (3) taking the liquid-phase product for gas chromatography analysis, and obtaining that the conversion rate of the ethylene carbonate is 61.7%, the selectivity of the dimethyl carbonate is 99.9% and the selectivity of the ethylene glycol is 99.9%.

[ example 15 ]

22.0 g of ethylene carbonate, 32.0 g of methanol and 0.22 g of magnesium silicide as a catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate: 4: 1, weight ratio of catalyst to ethylene carbonate: 0.01: 1) and reacted at 50 ℃ for 0.5 hour. After the reaction was complete, the autoclave was cooled to room temperature and vented. And (3) taking the liquid-phase product for gas chromatography analysis, wherein the conversion rate of the ethylene carbonate is 39.7%, the selectivity of the dimethyl carbonate is 99.9%, and the selectivity of the ethylene glycol is 99.9%.

[ example 16 ]

22.0 g of ethylene carbonate, 32.0 g of methanol and 0.22 g of magnesium silicide as a catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate: 4: 1, weight ratio of catalyst to ethylene carbonate: 0.01: 1) and reacted at 80 ℃ for 0.5 hour. After the reaction was complete, the autoclave was cooled to room temperature and vented. And (3) taking the liquid-phase product for gas chromatography analysis, wherein the conversion rate of the ethylene carbonate is 48.3%, the selectivity of dimethyl carbonate is 99.9%, and the selectivity of ethylene glycol is 99.9%.

[ example 17 ]

22.0 g of ethylene carbonate, 32.0 g of methanol and 0.22 g of magnesium silicide as a catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate: 4: 1, weight ratio of catalyst to ethylene carbonate: 0.01: 1) and reacted at 140 ℃ for 0.5 hour. After the reaction was complete, the autoclave was cooled to room temperature and vented. And (3) taking the liquid-phase product for gas chromatography analysis, wherein the conversion rate of the ethylene carbonate is 54.5%, the selectivity of the dimethyl carbonate is 99.9%, and the selectivity of the ethylene glycol is 99.9%.

[ example 18 ]

22.0 g of ethylene carbonate, 32.0 g of methanol and 0.22 g of magnesium silicide as a catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate: 4: 1, weight ratio of catalyst to ethylene carbonate: 0.01: 1) and reacted at 160 ℃ for 0.5 hour. After the reaction was complete, the autoclave was cooled to room temperature and vented. And (3) taking the liquid-phase product for gas chromatography analysis, and obtaining that the conversion rate of the ethylene carbonate is 61.4%, the selectivity of the dimethyl carbonate is 99.9% and the selectivity of the ethylene glycol is 99.9%.

[ example 19 ]

22.0 g of ethylene carbonate, 32.0 g of methanol and 0.22 g of lithium carbide as a catalyst were placed in a 100 ml autoclave (molar ratio of methanol to alkylene carbonate: 4: 1, weight ratio of catalyst to ethylene carbonate: 0.01: 1) and reacted at 120 ℃ for 2 hours. After the reaction was complete, the autoclave was cooled to room temperature and vented. After the catalyst was used repeatedly for 5 times, the liquid phase product was taken out and subjected to gas chromatography analysis, and the conversion of ethylene carbonate, the selectivity of dimethyl carbonate and the selectivity of ethylene glycol were obtained as shown in table 1.

TABLE 1

Number of times of use	Conversion of ethylene carbonate	Selectivity to dimethyl carbonate	Selectivity to ethylene glycol
				1	61.8％	99.8％	99.8％
2	61.7％	99.8％	99.9％
				3	61.5％	99.8％	99.8％
4	61.6％	99.8％	99.9％
				5	61.4％	99.8％	99.8％

According to the embodiment of the invention, magnesium silicide and/or lithium carbide are/is used as the catalyst for preparing dimethyl carbonate through the ester exchange reaction of alkylene carbonate and methanol, the conversion rate of the alkylene carbonate can reach more than 60%, the selectivity of the dimethyl carbonate can reach more than 99.7%, the selectivity of ethylene glycol can reach more than 99.8%, and after the catalyst is repeatedly used for many times, the activity is reduced by less than 5%, so that a better technical effect is achieved.

It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.