反应详情

Accordingly the present invention provides a method of producing dimethyl phthalate, which comprises treating phthalic anhydride with methanol, adding a catalyst, such as sulphuric acid, hydrochloric acid or mixture thereof and a promoter, such as, dimethyl sulphate; refluxing the resultant mixture at a temperature in the range of 60 to 100 degree Celsius, for a time period in the range of 6 to 12 hours, in the presence of benzene; separating the distillate into two layers; removing the aqueous layer and recycling the benzene layer, recovering unreacted methanol by distillation; neutralizing the residue with caustic soda followed by extraction with benzene; distilling the extract under vacuum to obtain benzene; continuing the distillation process at a temperature in the range of 145 to 146 degree Celsius under 10 mm of mercury to obtain dimethyl phthalate.

1. additionadding a catalyst
2. customin the range of 6 to 12 hours
3. customseparating the distillate into two layers
4. customremoving the aqueous layer
5. customrecovering unreacted methanol
6. distillationby distillation
7. extractionfollowed by extraction with benzene
8. distillationdistilling the
9. extractionextract under vacuum
10. customto obtain benzene
11. customin the range of 145 to 146 degree Celsius