Dimethyl carbonate is an important organic compound widely used in chemical industry, medicine, electronics and other fields. This article will introduce the production process and preparation method of dimethyl carbonate.

1、 Production process of dimethyl carbonate

The production process of dimethyl carbonate can be divided into two types: chemical method and physical method.

1） Chemical method

The chemical synthesis reaction equation of dimethyl carbonate is: CH3OH+CO2 → CH3OCO2CH3

Methanol is the raw material for dimethyl carbonate, and carbonate gas is the reactant. The reaction process requires a catalyst.

There are various catalysts, including sodium hydroxide, calcium oxide, copper oxide, and carbonate. Carbonate ester has the best catalytic effect, but the selection of catalyst also needs to consider factors such as cost and environment.

The production process of dimethyl carbonate mainly includes steps such as methanol purification, oxygen oxidation, heating reaction, separation/distillation, etc. During the reaction process, strict control of parameters such as temperature, pressure, and reaction time is required to improve yield and purity.

2）Physical method

There are two main physical methods for producing dimethyl carbonate: absorption method and compression method.

The absorption method uses methanol as an absorbent and reacts with CO2 at low temperatures to produce dimethyl carbonate. The absorbent can be reused, and the carbon dioxide generated by the reaction can also be recycled, but the reaction rate is slow and the energy consumption is high.

The compression law utilizes the physical properties of CO2 to come into contact with methanol under high pressure, thereby achieving the preparation of dimethyl carbonate. This method has a fast reaction rate, but requires high-power compression equipment and is costly.

The above two methods have their own advantages and disadvantages, and can be selected based on application needs and economic factors.

2、 Preparation method of dimethyl carbonate

There are various methods for preparing dimethyl carbonate, and the following are two commonly used methods:

1） Methanol method

This is the most commonly used method for preparing dimethyl carbonate. The specific operation steps are as follows:

(1) Add methanol and potassium carbonate/sodium carbonate, and heat to reaction temperature while stirring;

(2) Slowly add CO2, continue stirring, and cool down after the reaction is completed;

(3) Use a separation funnel to separate the mixture and obtain dimethyl carbonate.

It should be noted that temperature, pressure, reaction time, as well as the type and amount of catalyst need to be controlled during the reaction process to improve yield and purity.

2） Oxygen oxidation method

In addition to the methanol method, the oxygen oxidation method is also commonly used for the preparation of dimethyl carbonate. This method is easy to operate and can achieve continuous production.

The specific operation steps are as follows:

(1) Add methanol and catalyst, heat to reaction temperature while stirring;

(2) Add oxygen gas to the reaction system and continue stirring;

(3) Separate, distill, and purify the reaction mixture to obtain dimethyl carbonate.

It should be noted that the oxygen oxidation method requires controlling parameters such as the supply rate and reaction temperature of oxygen gas, as well as the proportion of reaction components, to improve yield and purity.

Through the introduction of this article, we can learn about the production process and preparation methods of dimethyl carbonate. From molecular structure to detailed description of reaction process and production method, we have provided a comprehensive and accurate knowledge system. I hope this article can inspire readers’ learning and research in this field.