Patent ID: 6733693
Filing Date: 2004-05-11
Classification: C07C,C07D

Abstract:
A method for the storage of an acrylonitrile solution of N-phenyl maleimide, which, in a forced coloration test, the values, &Dgr;L, &Dgr;a, &Dgr;b, are calculated in accordance with the following formulas:&Dgr;L=|L1âˆ’L2|(Absolute value) &Dgr;a=|a1âˆ’a2|(Absolute value) &Dgr;b=|b1âˆ’b2|(Absolute value) wherein L1, a1, and b1 are respectively the values of L, a, and b of said acrylonitrile solution before undergoing said forced coloration test and L2, a2, and b2, are respectively the values of L, a, and b of said acrylonitrile solution after undergoing said forced coloration test and are respectively 5 or less, 5 or less and 10 or less, wherein a molecular oxygen concentration of the gaseous phase portion of said solution is adjusted to a level in the range of 0.01 to 10% by volume preparatorily to storing said solution in contact with a metal, and water content is not more than 0.1% by weight.