CN1064346C - Direct synthesis method of dimethyl carbonate - Google Patents

Abstract

The invention provides a method for synthesizing dimethyl carbonate with carbon dioxide, a potential carbon resource, as the basic raw material. It first reacts magnesium and methanol to generate magnesium formate, and then uses carbon dioxide and methanol to perform gas-liquid reaction under the action of magnesium methanol to form dimethyl carbonate. Carbonic dicarboxylic acid. The process conditions of the method are: the content of magnesium accounts for 3-9% by weight of methanol; the reaction temperature of magnesium and methanol is 200°C, and the reaction time is 1 hour; the pressure of carbon dioxide gas is 10-50Kg/cm ² ; gas-liquid reaction The temperature is 120-200°C; the gas-liquid reaction time is 1-11 hours. The preparation method has simple process, easy operation, single product, no secondary environmental pollution, and good economic and social benefits.

Description

A kind of direct synthesis method of dimethyl carbonate

The present invention relates to the preparation method of organic compound, specifically refer to the method for directly synthesizing dimethyl carbonate by carbon dioxide and methanol.

Carbon dioxide is both a potential carbon source and a major cause of environmental problems such as the greenhouse effect. Many researchers are studying the comprehensive utilization of carbon dioxide. U.S. Patent No. 3,657,310 entitled: Synthesis of Aliphatic Carbonate, discloses the preparation of alkali metal salt of monomethyl carbonate by reacting carbon dioxide and alkali metal methoxide. Dimethyl carbonate is then prepared by the methylation of a halomethane. This method has not been developed industrially due to the use of expensive and dangerous metal sodium and highly toxic monohalomethane as raw materials. Another kind of method is U.S. Patent, 4,661,609 are titled: the co-synthesis of ethylene glycol and dimethyl carbonate, the disclosed transesterification method, namely first carbon dioxide and alkylene oxide are reacted to obtain cyclic carbonate, and then Dimethyl carbonate can be obtained by transesterification with methanol. This method needs to go through two-step reaction and two-step separation process, the process is complicated and the preparation cost is high.

The purpose of the present invention is to avoid the weak point of background technology, create a kind of process simple, cost is low, the method for directly synthesizing dimethyl carbonate by carbon dioxide that does not produce secondary environmental pollution, this method not only makes full use of the potential carbon dioxide of carbon dioxide Resources solve environmental problems and have very broad prospects for industrialization.

The object of the present invention is achieved through the following measures:

A kind of direct synthesis method of dimethyl carbonate, it is characterized in that, at first generate magnesium methylate by magnesium and methyl alcohol reaction, then carry out gas-liquid reaction generation dimethyl carbonate with carbon dioxide and methyl alcohol under the magnesium methylate effect, its reaction equation is as follows: Its technological conditions are as follows: (1) magnesium content accounts for 3～9% of methanol weight percent; (2) reaction temperature of magnesium and methanol reaction: 200 ℃, reaction time: 1 hour; (3) carbon dioxide pressure is 10～50Kg/ cm ² (4) The reaction temperature for the gas-liquid reaction of carbon dioxide and methanol under the action of magnesium methoxide is 120-200° C. (5) The reaction time for the gas-liquid reaction of carbon dioxide and methanol under the action of magnesium methoxide is 1-11 hours. The present invention and background Compared with the technology, it has the following advantages: 1. The preparation process of the present invention is simple, easy to operate, single product, and low in cost.

2. The preparation process of the present invention does not produce secondary environmental pollution, the source of raw materials is abundant, and carbon dioxide, a potential carbon resource, is fully utilized.

3. The industrialization prospect of the present invention is good. At present, dimethyl carbonate is not only used as methylation, carbonylation reagent and organic synthesis intermediate, but also can be used as a new type of fuel additive. It can replace methyl tert-butyl Ether, and quite effective in increasing the octane number and oxygen content of fuel.

Therefore, the present invention has good economic benefit and social benefit.

The present invention will be further described below in conjunction with embodiment:

Example 1:

Weigh 10 grams of metal magnesium, add it into the autoclave and mix it with 200 ml of methanol, seal it and react at 200°C for 1 hour, after cooling, let 30Kg/ ^cm2 of carbon dioxide gas into it, react at 180°C for 5 hours, cool down, Exclude the remaining gas, and separate the product by distillation. The yield of dimethyl carbonate is 16.4% (molar ratio) of the carbon dioxide raw material gas.

Example 2:

Weigh 5 grams of magnesium metal, put it into an autoclave and mix it with 200 ml of methanol, seal it and react at 200°C for 1 hour, after cooling, let 30Kg/ ^cm2 of carbon dioxide gas into it, react at 140°C for 2 hours, cool down, Exclude the remaining gas, and separate the product by distillation. The yield of dimethyl carbonate is 4.46% (molar ratio) of the carbon dioxide feed gas.

Example 3

Weigh 13 grams of magnesium metal, add it to the autoclave and mix it with 200 ml of methanol, seal it and react at 200°C for 1 hour, after cooling, let 10Kg/ ^cm2 of carbon dioxide gas into it, react at 200°C for 8 hours, cool down, Exclude residual gas and separate the product by distillation. The yield of dimethyl carbonate is 15.9% (molar ratio) of carbon dioxide feed gas.

Example 4:

Weigh 10 grams of magnesium metal, put it into an autoclave and mix it with 200 ml of methanol, seal it and react at 200°C for 1 hour, after cooling, let 50Kg/ ^cm2 of carbon dioxide gas react at 160°C for 10 hours, cool, and remove The remaining gas is separated by distillation to obtain the product, and the yield of dimethyl carbonate is 10.1% (molar ratio) of the raw gas of carbon dioxide.

Claims (1)

1. The direct synthesis process of dimethyl carbonate features that magnesium and methanol are first reacted to produce magnesium methoxide, and then carbon dioxide and methanol are reacted under the action of magnesium methoxide to produce dimethyl carbonate, with the reaction equation as follows:

   

   the process conditions are as follows:

   (1) the total amount of magnesium accounts for 3-9% of the weight of the methanol;

   (2) the reaction temperature of the reaction of magnesium and methanol is 2O0 ℃, and the reaction time is 1 hour;

   (3) the pressure of the carbon dioxide gas is 10-50 Kg/cm²；

   (4) The reaction temperature of the gas-liquid reaction of the carbon dioxide and the methanol under the action of the magnesium methoxide is l 20-200 ℃;

   (5) the reaction time of the gas-liquid reaction of the carbon dioxide and the methanol under the action of the magnesium methoxide is 1-1 l hour.