Process for the manufacture of cationic hydrazone dyes
US4026885A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 27, 1976 |
| Grant date | May 31, 1977 |
| Priority date | — |
| Expiry date | Apr 27, 1996 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09B26/04
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A process for the manufacture of dyes of the formula ##STR1## WHEREIN EACH OF R.sub.1 and R.sub.2 represents a methyl or ethyl radical, n is 1 or 2, X.sup.- is the charge equivalent of an anion and B represents a divalent radical which completes the ring a to form a pyridinium or quinolinium ring which is unsubstituted or substituted by chlorine or methyl, and the ring b is unsubstituted or substituted by low molecular alkyl or alkoxy or by halogen, which process comprises treating a compound of the formula ##STR2## WHEREIN R.sub.1, n, X.sup.-, B, a and b are as defined in formula (1) and m is 1 or 2, in aqueous medium at a pH of 12 or above, with dimethyl or diethyl sulphate, with the proviso that if m=1, at least 2 equivalents of dimethyl or diethyl sulphate are used.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.