| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing highly pure 4,4'-bis(3-tosylureido)diphenylmethane useful as a color developer of a heat-sensitive recording medium, at a low cost. SOLUTION: The method for producing 4,4'-bis(3-tosylureido)diphenylmethane, including a process of reacting tosylisocyanate with 4,4'-diaminodiphenylmethane in a reaction solvent, is characterized by using a mixed solvent comprising acetonitrile and ethyl acetate in a mass ratio of acetonitrile/ethyl-acetate in a range of 45/55 to 70/30, as the reaction solvent. COPYRIGHT: (C)2011,JPO&INPIT
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