There are two main synthesis methods of sorbic acid. One is the reaction of crotonaldehyde and acetone under specific conditions, and the other is the reaction of crotonaldehyde and ketene as raw materials under specific process conditions. This is the most commonly used synthesis method. The crotonaldehyde is mainly derived from the condensation of acetaldehyde, while the ketene is produced by the cracking of acetic acid, and further produced by the reaction of sorbic acid with potassium hydroxide to produce potassium sorbate.

In terms of raw materials, tap water needs to pass through an ion exchanger to prepare deionized water and store it in a pool for later use. Then add a certain amount of deionized water to the lye dilution tank with a content of 92% potassium hydroxide to dilute to 49% And spare. During the synthesis process, a quantitative amount of sorbic acid needs to be added to the reaction kettle, and then vacuum-pump ionized water into the measuring cylinder, the amount is about 60% of the sorbic acid, and start stirring at the same time, and then vacuum the prepared lye to the lye storage tank , Further add potassium hydroxide solution dropwise into the reaction kettle to start the acid-base neutralization reaction, then open the jacket cooling water of the reaction kettle to control the reaction temperature at about 40°C, take samples after the reaction proceeds for 30 minutes, and use an acidity meter To determine the pH of the reaction solution, stop adding lye when the pH of the reaction solution is ≥9.5. The reaction process should be ≤45 min. After stirring for 1 hour, the reaction solution is pumped into the storage tank, and then vacuum filtered, and the lye obtained from the filter tank is stored in the storage tank. The filtered activated carbon can be regenerated and reused. After the lye is pumped into the concentration tank, it is heated with jacketed heat transfer oil to ensure that the temperature of the lye is 40-50 ℃, and the vacuum degree is 0.1MPa, and then the vacuum evaporation is carried out. Normally, the evaporation time is 3 to 4 hours. After the technical standard, the temperature is raised to 70 ℃ to continue discharging, and then sent to the centrifugal section, and then use a three-foot centrifuge for dehydration. After the lye is evaporated, the centrifugal separation solution becomes the mother liquor. The mother liquor continues to be evaporated under reduced pressure to obtain semi-finished products. The separated solution is the secondary mother liquor. After 7 times of recovery, the semi-finished product can meet the requirements, it is discharged from the upper part of the centrifuge, and then transported to the drying section to be dried at 105 ℃ until the index meets the product requirements, and finally sent to The packing section carries out packing and packing into the warehouse.