How to separate dimethyl carbonate from water

An azeotrope is formed; I think it’s not possible to separate them directly. It is recommended to add an organic substance that forms an azeotrope with water at a lower boiling point, and this substance can be separated from water using methods such as extraction. The product can then be obtained through azeotropic distillation

The logic is a bit confusing – sometimes it’s extraction separation, and other times it’s azeotropic distillation!

Separation by distillation is used; the formation of an azeotrope facilitates easy separation

The light-end removal column, after gas-liquid separation, undergoes distillation; the reaction by-products methyl formate, methyl acetate, along with a certain amount of methanol and DMC, are obtained from the top of the column. The materials taken from the column are returned to the reaction system, while the material at the bottom of the column, together with the vapor from the water phase at the top, enters a mixer and is then cooled before being sent to an extractor for extraction and separation； The extracted ester phase material is sent to the product distillation tower for separation; the vapor from the top of the tower goes into the material mixer, while the DMC product is obtained at the bottom of the tower ； The extracted aqueous phase material is separated in an aqueous phase distillation tower; the reaction liquid from the top of the tower goes to the material mixer, while the material from the bottom of the tower enters the methanol recovery tower ； The methanol obtained from the top of the methanol recovery tower is returned to the reaction system. To enhance the extraction efficiency, some of the distillates from the lower part of the tower are sent back to the material mixer, while wastewater is discharged from the bottom of the tower.

A water extraction distillation process for separating dimethyl carbonate, characterized in that the feed material is a mixture containing an azeotrope of dimethyl carbonate (DMC) and methanol along with water; this mixture enters continuously from the middle section of the water extraction distillation tower. Water is sprayed from the top of the tower into the extraction zone. The gas phase at the top of the tower, after being condensed in a condenser, is separated into an aqueous phase composed mainly of water and an oily phase composed mainly of DMC. The oily phase goes to the product distillation tower, while the aqueous phase returns to the mixture in the middle section of the water extraction distillation tower. The liquid at the bottom of the tower consists mainly of a methanol-water solution, which is sent to a methanol recovery unit for recovery. The water remaining after methanol has been separated is used as extraction water and sent back to the water extraction distillation tower.

The answers upstairs were very professional; I learned a lot from them

The production technology for DMC is quite mature these days, so separating DMC from methanol should not be a problem either