Processes for the purification of...

Details Processes for the purification of... Processes for the purification of...

2007-05-01

2007-05-01

Drodge, Joseph (Department: 1723)

Liquid purification or separation

Processes

Liquid/liquid solvent or colloidal extraction or diffusing...

C023S299000, C203S039000, C203S089000, C210S774000, C210S806000, C521S048000, C528S308100

Reexamination Certificate

active

10481989

ABSTRACT:
A method is disclosed for efficiently obtaining BHET of high purity from an EG (ethylene glycol) solution containing crude BHET (bis(2-hydroxyethyl)terephthalate), especially a decomposition product solution obtained by decomposing a polyester containing PET (polyethylene terephthalate) as a main component, by use of EG, while minimizing by-production of impurity components such as DEG (diethylene glycol), DEG ester and oligomers. The decomposition product solution is subjected to crystallization and solid-liquid separation under specific temperature conditions. Further, in accordance with the invention, a method of purifying BHET is taught which comprises evaporation steps of evaporating low-boiling-point components from the decomposition product solution under specific conditions so as to obtain a melt solution and a molecular distillation step of distilling the obtained melt solution under specific conditions so as to obtain a specific fraction.

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