Preparation methods of 2,2-dimethyl-1,3-dioxolane and ethylene glycol

Abstract

The invention provides a preparation method of 2,2-dimethyl-1,3-dioxolane. The method comprises the steps that: under a cyclization reaction condition, ethylene oxide and acetone contact a catalyst, such that a mixture is obtained; and the 2,2-dimethyl-1,3-dioxolane is separated from the mixture, wherein the catalyst comprises ionic liquid 1-alkyl-3-methylimidazolium salt and anhydrous zinc chloride. The invention also provides a preparation method of ethylene glycol. According to the 2,2-dimethyl-1,3-dioxolane preparation method provided by the invention, the catalyst composed of the ionic liquid 1-alkyl-3-methylimidazolium salt and anhydrous zinc chloride is adopted, such that defects such as high catalyst cost and severe environment pollution of prior arts in which zinc trifluoromethanesulfonate is adopted as a catalyst for catalyzing the reaction of ethylene oxide and acetone are solved. Also, catalytic efficiency is improved compared with a method for using single anhydrous zinc chloride as a catalyst to replace zinc trifluoromethanesulfonate, and catalyst recycling and reutilization can be facilitated.

Description

technical field

[0001] The present invention relates to a method for preparing 2,2-dimethyl-1,3-dioxolane and a method for preparing ethylene glycol. Background technique

[0002] The existing ethylene glycol production process is mainly to react ethylene oxide with a large amount of water under high temperature and high pressure, and the mass ratio of the two is about 1:10. Consumption is large, and equipment investment is also relatively large. There is also a process of first reacting ethylene oxide with acetone to generate 1,3-dioxolane compounds, and then hydrolyzing it to prepare ethylene glycol. This process solves the problem of large energy consumption and equipment in the traditional ethylene oxide hydrolysis process. The problem of large investment can reduce the by-product diethylene glycol while reducing the water consumption. However, the key to this process lies in the preparation of 1,3-dioxolane compounds.

[0003] At present, there are many methods for p...

Examples

Embodiment approach

[0022] According to a preferred embodiment of the present invention, the cation of the ionic liquid 1-alkyl-3-methylimidazolium salt is 1-butyl-3-methylimidazolium, and the anion is bromide, chloride, trifluoro One of methanesulfonate ion, methanesulfonate ion, p-toluenesulfonate ion.

[0023] Specifically, the ionic liquid 1-alkyl-3-methylimidazolium salt can be 1-butyl-3-methylimidazole bromide, 1-butyl-3-methylimidazole chloride, 1-butyl -3-methylimidazolium bisulfate, 1-butyl-3-methylimidazolium methanesulfonate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methyl imidazole p-toluenesulfonate, etc., more preferably the ionic liquid is 1-butyl-3-methylimidazole bromide. The ionic liquids mentioned above can be prepared by methods known in the art (see "Green Reaction Media in Organic Synthesis" edited by Koichi Mikami, 2005, Blackwell Publishing Ltd. et al.).

[0024] According to a preferred embodiment of the present invention, the ionic liquid 1-alky...

Embodiment 1

[0045] Put the magnetic stirring bar into a 25mL polytetrafluoroethylene-lined reaction kettle, add 0.1mol (5.8g) acetone, 0.025mol (1.1g) ethylene oxide, and then add 0.01mol 1-butyl bromide- 3-Methylimidazolium ionic liquid and 0.005mol (0.68g) of anhydrous zinc chloride are uniformly mixed as a catalyst, and the reaction kettle is closed, and stirred and reacted for 8 hours in an oil bath at 65°C. After the reaction was completed and cooled to room temperature, a liquid sample was taken for analysis. The conversion rate of ethylene oxide was 99%, and the selectivity of 2,2-dimethyl-1,3-dioxolane was 100%.

Embodiment 2

[0052] The reaction mixture obtained in Example 1 was distilled under the protection of nitrogen. After the product and the raw material were completely separated by distillation, the rest was the ionic liquid containing zinc chloride. Prepare 2,2-dimethyl-1,3-dioxolane according to the method of Example 1, and replace the catalyst of Example 1 with the recovered ionic liquid containing zinc chloride to prepare 2,2-dimethyl-1,3-dioxolane 1,3-dioxolane. The conversion of ethylene oxide was 99%, and the selectivity to 2,2-dimethyl-1,3-dioxolane was 98%.

technical field

[0001] The present invention relates to a method for preparing 2,2-dimethyl-1,3-dioxolane and a method for preparing ethylene glycol. Background technique

[0002] The existing ethylene glycol production process is mainly to react ethylene oxide with a large amount of water under high temperature and high pressure, and the mass ratio of the two is about 1:10. Consumption is large, and equipment investment is also relatively large. There is also a process of first reacting ethylene oxide with acetone to generate 1,3-dioxolane compounds, and then hydrolyzing it to prepare ethylene glycol. This process solves the problem of large energy consumption and equipment in the traditional ethylene oxide hydrolysis process. The problem of large investment can reduce the by-product diethylene glycol while reducing the water consumption. However, the key to this process lies in the preparation of 1,3-dioxolane compounds.

[0003] At present, there are many methods for p...

Examples

Embodiment approach

[0022] According to a preferred embodiment of the present invention, the cation of the ionic liquid 1-alkyl-3-methylimidazolium salt is 1-butyl-3-methylimidazolium, and the anion is bromide, chloride, trifluoro One of methanesulfonate ion, methanesulfonate ion, p-toluenesulfonate ion.

[0023] Specifically, the ionic liquid 1-alkyl-3-methylimidazolium salt can be 1-butyl-3-methylimidazole bromide, 1-butyl-3-methylimidazole chloride, 1-butyl -3-methylimidazolium bisulfate, 1-butyl-3-methylimidazolium methanesulfonate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methyl imidazole p-toluenesulfonate, etc., more preferably the ionic liquid is 1-butyl-3-methylimidazole bromide. The ionic liquids mentioned above can be prepared by methods known in the art (see "Green Reaction Media in Organic Synthesis" edited by Koichi Mikami, 2005, Blackwell Publishing Ltd. et al.).

[0024] According to a preferred embodiment of the present invention, the ionic liquid 1-alky...

Embodiment 1

[0045] Put the magnetic stirring bar into a 25mL polytetrafluoroethylene-lined reaction kettle, add 0.1mol (5.8g) acetone, 0.025mol (1.1g) ethylene oxide, and then add 0.01mol 1-butyl bromide- 3-Methylimidazolium ionic liquid and 0.005mol (0.68g) of anhydrous zinc chloride are uniformly mixed as a catalyst, and the reaction kettle is closed, and stirred and reacted for 8 hours in an oil bath at 65°C. After the reaction was completed and cooled to room temperature, a liquid sample was taken for analysis. The conversion rate of ethylene oxide was 99%, and the selectivity of 2,2-dimethyl-1,3-dioxolane was 100%.

Embodiment 2

[0052] The reaction mixture obtained in Example 1 was distilled under the protection of nitrogen. After the product and the raw material were completely separated by distillation, the rest was the ionic liquid containing zinc chloride. Prepare 2,2-dimethyl-1,3-dioxolane according to the method of Example 1, and replace the catalyst of Example 1 with the recovered ionic liquid containing zinc chloride to prepare 2,2-dimethyl-1,3-dioxolane 1,3-dioxolane. The conversion of ethylene oxide was 99%, and the selectivity to 2,2-dimethyl-1,3-dioxolane was 98%.

Images