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Indexed by: Journal Article

Date of Publication: 1996-12-01

Journal: DYES AND PIGMENTS

Included Journals: Scopus、SCIE

Volume: 32

Issue: 4

Page Number: 193-198

ISSN: 0143-7208

Key Words: direct dyes; phosgene; triphosgene; phosgenation; carbonylation; N,N'-substituted urea

Abstract: Using triphosgene as a substitute for phosgene, many 'urea-containing' direct dyes or intermediates (i.e. containing the ureylene-NHCOHN-system) can be safely and conveniently synthesised. The phosgenation is affected by hydrolysis side-reactions and the yields of product are dependent on the relative reactivity of the reacting amino groups, pH, temperature and the excess of triphosgene used. J-acid urea, C.I. Direct Yellow 50, and C.I. Direct Red 75 were obtained in high yield (> 93%) and with only a slight excess of triphosgene. Copyright (C) 1996 Elsevier Science Ltd