| 摘要 |
A method for separating and recovering dimethyl terephthalate (DMT) and ethylene glycol (EG) from a polyester (polyethylene terephthalate (PET)) waste containing foreign matter, which comprises a step of treating a polyester waste in the EG containing a depolymerization catalyst at 175 to 190C under 0.1 to 0.5 Mpa and removing the solid foreign matter floating on the surface of the resultant liquid reaction mixture by the flotation method, a step of removing the residual solid foreign matter from the resultant mixture by the solid liquid separation method, a step of subjecting the resultant solution to distillation and condensation and recovering the EG having distilled out, a step of adding a transesterification catalyst and methanol to the resulting residual solution to effect a transesterification between the residual solution and methanol to thereby form DMT and EG and subjecting the resultant reaction mixture to a recrystallization treatment followed by a centrifugal separation treatment, to thereby separate the mixture into a cake of DMT and a mixed solution, and subjecting the cake to rectification to distill out and recover a high purity DMT, a step of subjecting the residual mixed solution to distillation to recover methanol, and a step of subjecting the resultant residue to distillation to recover EG. |
