Propylene glycol methyl ether acetate: reactions, acidity issues
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In the production process of propylene glycol methyl ether acetate (PMA), 1. the esterification rate in the reactor is low; 2. the temperature at the bottom of the dehydration tower is low while the temperature at the top is high, and the use of water-adding agents is not effective. 3. The temperature in the light-end removal tower is acceptable; the top temperature is low due to an excessive amount of light components. The acidity cannot be reduced. Please, someone knowledgeable can help resolve this issue.
The low temperature in the reactor is caused by high moisture levels; the high moisture content in the reactor liquid is due to insufficient return flow of the water-carrying agent or the inclusion of an aqueous phase in the return stream. The high temperature at the top of the tower means that the conditions there are not close to the azeotropic composition of the water-carrying agent and water； Furthermore, with a high moisture level in the tower bottom, the conversion rate of PM will definitely decrease. The excessive acid level in the bottom stream of the light-end removal tower indicates that the separation efficiency is very poor.