Title:
METHOD OF PURIFYING CRUDE DIPHENYLMETHANE DIISOCYANATE
Document Type and Number:
WIPO Patent Application WO/2006/040912
Kind Code:
A1
Abstract:
[PROBLEMS] To provide a method by which the amount of hydrolysable chlorine contained in crude diphenylmethane diisocyanate is reduced to 0.03% or less in a short time. [MEANS FOR SOLVING PROBLEMS] The method of purifying crude diphenylmethane diisocyanate is characterized by passing a gas selected among acid gases and inert gases through crude diphenylmethane diisocyanate having a hydrolysable-chlorine content of 0.05% or higher in the presence of a metal oxide under the conditions of a temperature of 150-250°C and a pressure of 5-25 kPa at a flow rate of 50-250 ml/min per 1,000 g of the crude diphenylmethane diisocyanate in terms of ordinary-pressure gas amount to thereby yield purified diphenylmethane diisocyanate having a hydrolysable-chlorine content of 0.03% or lower.
Inventors:
YOSHII NAOYA (JP)
KOBAYASHI TOSHIHIDE (JP)
YAMAGUCHI TATSUYA (JP)
KOBAYASHI TOSHIHIDE (JP)
YAMAGUCHI TATSUYA (JP)
Application Number:
PCT/JP2005/017362
Publication Date:
April 20, 2006
Filing Date:
September 21, 2005
Export Citation:
Assignee:
NIPPON POLYURETHANE KOGYO KK (JP)
YOSHII NAOYA (JP)
KOBAYASHI TOSHIHIDE (JP)
YAMAGUCHI TATSUYA (JP)
YOSHII NAOYA (JP)
KOBAYASHI TOSHIHIDE (JP)
YAMAGUCHI TATSUYA (JP)
International Classes:
C07C263/20; C07C265/14
Foreign References:
| JPH06345707A | 1994-12-20 | |||
| JPS5988452A | 1984-05-22 | |||
| JPS4217887B1 | ||||
| JPS4219450B1 |
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