The ketene method, also known as th

The ketene method, also known as the acetic acid cracking method, is a low-pressure high-temperature reaction that uses acetic acid as a raw material to produce acetic anhydride. The raw material and triethyl phosphate are used as catalysts. The whole process is divided into two steps. First, gas-phase acetic acid is cracked to produce vinyl ketone, and then acetic acid and vinyl ketone are absorbed to produce crude acid anhydride, and acetic anhydride of higher purity is obtained by distillation and purification. The biggest feature of this method is that the production process is complicated, there are many side reactions, and the energy consumption is large, but because the process is close to perfect, the production safety is high. In addition, the quality requirements for acetic acid in the acetic acid cracking section are low, and other devices and recovered acetic acid can be used. Therefore, this method is still widely used in the early construction of domestic and foreign equipment. Vinyl ketone, the product of acetic acid cleavage, is an important intermediate. It can be used as a raw material for the production of pesticides and food preservatives. This product was not formed during the carbonylation process. Therefore, the cracking process of vinyl ketone is highly feasible.