Acetic anhydride, also known as acetic anhydride, is an important chemical raw material and acetylation agent, which has a wide range of uses in medicine, dyes, spices, pesticides and other fields. At present, the industrial production of acetic anhydride in China mainly includes two processes: carbonyl synthesis and acetic acid cracking, with a total market circulation capacity of about 700,000 tons, of which the carbonyl synthesis process has a capacity of 150,000 tons, and the others are acetic acid cracking processes.In the process of carbonyl synthesis, methyl acetate is first formed by methanol and acetic acid under the action of catalyst, and then methyl acetate is carbonylated with methanol and carbon monoxide in the presence of iodomethane and rhodium catalyst to form acetic anhydride and co-produce acetic acid. The reaction equation is:
The carbonyl synthesis process has the advantages of low energy consumption, less three wastes emission, stable operation and superior comprehensive cost, but the process is relatively complex, the operation technology is high, and the production equipment investment is large, so there are fewer devices using this production process in China.
Acetic acid cracking method, also known as ketene method, first acetic acid in 700-750℃, 10-20kPa pressure and triethyl phosphate as a catalyst under the condition of cracking dehydration to produce ketene, and then liquid acetic acid absorption ketene to produce acetic anhydride, after distillation and purification to produce finished acetic anhydride. The reaction equation is:
The energy consumption of acetic acid cracking process is relatively high, and the three wastes are discharged more. However, due to the maturity of the process technology and the relatively small investment in equipment, this process has been adopted in new installations in China in recent years.
At present, the domestic capacity of acetic anhydride cracking method accounts for 79% of the total capacity, and the new capacity planned in the later stage is basically this process. In a fully competitive market environment, the industry price basically fluctuates around the cost line of the cracking process. The raw material of the process is acetic acid, and its production cost is directly linked to the price of acetic acid. In recent years, the price of acetic acid fluctuates greatly, and the cost of cracking method fluctuates greatly. By comparing the price trend of acetic anhydride and acetic acid in the past two years, it can be seen that the price trend of domestic acetic anhydride is basically the same as that of acetic acid.
Shandong Desenlai Chemical has been deeply cultivated in acetic acid and acetic anhydride industry for more than ten years, with excellent product quality, stable device operation and extensive channel coverage, which can meet the specific needs of various industries, and form close cooperative relations with high-quality customers in the industry, and has always enjoyed a good reputation in the industry. Welcome new and old friends to strengthen cooperation, mutual benefit and win-win!
