Patent · US Expired

Process for splitting polycarbonates

US5440066A · kind A · utility

7Cited by

2References

5Claims

0Family size

Assignee

BAYER HEALTHCARE LLC · DE

Inventors

Hans-Josef Buysch · Krefeld, DE
Norbert Schon · Krefeld, DE
Steffen Kuhling · Meerbusch, DE
Heinrich Hähnsen · Duisburg, DE

Key dates

Filing date	Apr 4, 1994
Grant date	Aug 8, 1995
Priority date	—
Expiry date	Apr 4, 2014

Classification

Technology area (CPC Y)Emerging Cross-Sectional Technologies
CPC primaryY10S203/06
WIPO fieldOrganic fine chemistry
WIPO sectorChemistry

Abstract

A continuous process for splitting an aromatic polycarbonate resin is disclosed. Accordingly there are reacted in a distillation column and in the presence of a catalyst (i) a polycarbonate resin in solution with (ii) methanol to produce a dihydroxy compound and dimethyl carbonate. The solution which contains polycarbonate and monohydroxy compound solvent exclusive of methanol is fed into the upper section of said column and the methanol is fed into the lower section of the column. The methanol is fed in the form of a mixture containing methanol and about 1-50 weight percent of dimethyl carbonate. The dimethyl carbonate thus produced is removed from an upper section of the column and the dihydroxy compound is removed from a lower section of the column.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.