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US 4,026,885 AGranted
Process for the manufacture of cationic hydrazone dyes
AssigneeCiba-Geigy Corporation
InventorsChristian Frey, Peter Moser
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AssigneeCiba-Geigy Corporation
InventorsChristian Frey, Peter Moser
Estimating the term…
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.
A process for the manufacture of dyes of the formula ##STR8## 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 ##STR9## 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.
Dependencies are inferred from the claim text.