Dimethyl carbonate turned into a big chemical product

Zhejiang Petrochemical Co., Ltd. announced on October 10 that the company's annual production of 200,000 tons of dimethyl carbonate (DMC) combined with 132,000 tons of ethylene glycol project has been successfully started, which is the largest single unit capacity in the world.  

Four good things emerge from this message:  

First, the capacity of a single set has been increased by an order of magnitude, making it possible for dimethyl carbonate to shift from organic chemical intermediates to bulk chemicals:  

The second is to provide a mature technical basis for large-scale transesterification production of polycarbonate supporting enterprises;  

Third, the co-production of ethylene glycol has a better and larger market, changed the propylene glycol market is difficult to expand the dilemma;  

Fourth, it is possible to replace MTBE as gasoline additive.  

Dimethyl carbonate (DMC) is an important organic chemical intermediate. Because its molecular structure contains carbonyl, methyl, methoxyl and carbonyl methoxyl, it can be widely used in organic synthesis reactions such as carbonylation, methylation, methoxylation and carbonyl methylation, and is used in the production of polycarbonate, isocyanate and other chemical products.  As DMC is non-toxic, it can be used as methylating agent or carbonylation agent instead of highly toxic phosgene, methyl chloroformate, dimethyl sulfate and so on.  As a solvent, DMC can replace freon, trichloroethane, trichloroethylene, benzene, xylene and other paints and cleaning solvents.  In addition, DMC can also be used as detergent, surfactant and softener additives.  

Despite its wide range of uses, existing processes and production costs make it difficult for dimethyl carbonate to become a major chemical product.  

The main problems are as follows: 

First, although electrolyte, developer, coating and adhesive of lithium battery have been widely used, it is difficult to be scaled up; 

Second, the more mature propylene oxide route produced propylene glycol market is difficult to develop, the two products often appear "lame";  

Third, the premise for gasoline additives must have a large reduction in cost, but the reality is difficult to do;  

Fourth, it is used as raw material for polycarbonate synthesis. The purity and quantity of propylene (ethyl) carbonate ester must meet the requirements of the conditional follow-up device.  Therefore, the process development route and use of dimethyl carbonate have been two hot spots in the industry.  These problems will be solved with the production of this large-scale device.  

1. A single set of production capacity from several thousand tons to 200,000 tons, increased by an order of magnitude, entering the gasoline additive market in terms of output and price becomes possible.  

As a gasoline additive, DMC can improve its octane number and oxygen content, and then improve its anti-knock property.  DMC has the properties of high oxygen content (oxygen content in the molecule is up to 53%), excellent octane number improvement (octane number is up to 105), no phase separation, low toxicity and rapid biodegradation, so that the amount of DMC used in gasoline to reach the same oxygen content is 4.5 times less than methyl tert-butyl ether (MTBE).  Therefore, DMC will become one of the most potential gasoline additives to replace MTBE.  

However, to replace MTBE, volume and price must be satisfied.  

China's gasoline consumption is at the level of 130 million tons, MTBE consumption is 10 million tons, even if a part of the replacement, the production of dimethyl carbonate must reach several million tons.  Obviously, the yield of dimethyl carbonate under existing processes is not even remotely different.  

The most important thing is the price. I looked at the price of dimethyl carbonate on the Internet. Recently, the price rose all the way up to 12,000 yuan/ton.  Even at the lowest end of the market, the price of dimethyl carbonate is hardly sufficient for the use of gasoline additives.  Most of the propylene oxide required by domestic existing production enterprises is purchased from outside (self-produced propylene is also purchased from outside).  

Zhejiang Petrochemical Co., LTD. 's dimethyl carbonate plant is one of the joint plants, ethylene direct oxidation route can ensure a continuous supply of ethylene oxide raw materials and low cost (propylene oxide and ethylene oxide prices are 18,000 yuan and 7,200 yuan/ton respectively).  Once the market returns to normal years, the price of dimethyl carbonate will fall with the rapid increase in market volume, making replacement possible.  

Environmental policies and transesterification of co2 consumption are also driving the development of dimethyl carbonate.  

The picture shows a single transesterification dimethyl carbonate plant with an annual output of 200,000 tons using ethylene oxide as raw material  

2. Another advantage of ethylene oxide ester exchange production is that the glycol market is good.  

Propylene glycol produced by propylene oxide route has been limited by small market capacity and difficult market development, and often appears to be bought at a loss.  The two products can also be "lame", with both good and bad, even using propylene glycol as a by-product of dimethyl carbonate production.  According to the news, the ethylene glycol products reached the main content of 99.9% or more of the national standard polyester grade.  Therefore, glycol produced by the dimethyl carbonate process will be very competitive with the daily demand for glycol.  

3. Ethylene oxide and carbon dioxide production of vinyl carbonate, for large-scale transesterification method of production of polycarbonate supporting enterprises to provide a mature technical basis.  

With the maturity and adoption of non-phosgene production polycarbonate process, the demand for vinyl carbonate will be tens of thousands of tons (there have been data show that using non-phosgene transesterification process, the production of 1 T PC needs to consume 0.35 T DMC equivalent).  According to reports, this process in addition to large capacity, there are three technological breakthroughs, including innovation of green homogeneous ionic liquid synthesis catalyst, making the reaction conditions more mild, conversion and yield greatly improved;  The injection reactor was used to solve the risk of large amount of ethylene oxide entering the reaction system.  The separation system of vinyl carbonate was innovated to solve the separation problem caused by the easy decomposition of vinyl carbonate.  

Therefore, the successful operation of the unit will ease the domestic demand for vinyl carbonate products, provide a polyester grade glycol production route with less investment and low cost for large oil refining enterprises with ethylene oxide and carbon dioxide, and provide a mature technical basis for large-scale transesterification production of polycarbonate supporting enterprises.