| 摘要 |
In purifying methyl methacrylate by feeding a feed mixture containing methanol, methyl methacrylate and 0.05 to 2% by weight, based on the weight of the methyl Methacrylate, of methyl isobutyrate to a first distillation column, subjecting the same to distillation therein in the presence of a saturated hydrocarbon having 6 or 7 carbon atoms while distilling out said saturated hydrocarbon, the methanol, a small amount of the methyl methacrylate and the methyl isobutyrate through the top of the first distillation column and simultaneously recovering methyl methacrylate freed from methanol and methyl isobutyrate from the bottom of the distillation column, wherein the top distillate is cooled in the decanter to be separated into two layers, the resulting upper layer composed mainly of the saturated hydrocarbon is returned to the first distillation column and the resulting lower layer composed mainly of methanol is fed to a second distillation column in which distillation is conducted while recovering the saturated hydrocarbon dissolved in the lower layer together with a part of the methanol from the top of the second distillation column and sending the same to the decanter, and withdrawing methanol, methyl isobutyrate and a small amount of methyl methacrylate from the bottom of the second distillation column, the methyl methacrylate can be effectively purified in high yield by allowing the saturated hydrocarbon to be present only above the feed stage of the first distillation column to which the feed mixture is fed, cooling the top distillate of the first distillation column to 0 DEG -13 DEG C. in the decanter, providing distillation stages above the feed stage of the second distillation column and conducting distillation while returning a part of the top distillate of the second distillation column to the top of the second distillation column, thereby separating methanol and methyl isobutyrate from methyl methacrylate. |
