[C:1]1(=[O:11])[O:6][C:4](=[O:5])[C:3]2=[CH:7][CH:8]=[CH:9][CH:10]=[C:2]12.S(=O)(=O)(O)O.Cl.S([O:23][CH3:24])(OC)(=O)=O.[CH:25]1C=CC=CC=1>CO>[C:4]([O:23][CH3:24])(=[O:5])[C:3]1[C:2](=[CH:10][CH:9]=[CH:8][CH:7]=1)[C:1]([O:6][CH3:25])=[O:11]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.
読み込み中…
