DK130416C

1332705 Preparation of azo pigments CIBAGEIGY AG 26 Nov 1970 [27 Nov 1969] 56264/70 Heading C4P Metal-free azo pigments containing no sulphenic acid groups are prepared by adding an ester of nitrous acid at -50‹- + 100‹ C. to an anhydrous reaction mixture comprising (a) a diazotizable amine, (b) a c...

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Bibliographic Details
Main Authors ROCHAT A C, STOCKER-BOLLER E J A
Format Patent
LanguageEnglish
Published 14.07.1975
Edition2
Subjects
ADHESIVES
CHEMISTRY
DYES
LAKES
METALLURGY
MISCELLANEOUS APPLICATIONS OF MATERIALS
MISCELLANEOUS COMPOSITIONS
MORDANTS
NATURAL RESINS
ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES
PAINTS
POLISHES
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Summary:1332705 Preparation of azo pigments CIBAGEIGY AG 26 Nov 1970 [27 Nov 1969] 56264/70 Heading C4P Metal-free azo pigments containing no sulphenic acid groups are prepared by adding an ester of nitrous acid at -50‹- + 100‹ C. to an anhydrous reaction mixture comprising (a) a diazotizable amine, (b) a coupling component, (c) an organic acid having- a PKa value of less than 3À0, and (d) one or more organic, non-water soluble solvents having a dielectric constant of less than 15, the molar ratio (c)/(a) being less 'than 1. The solvents used in the process are suitably aliphatic, optionally halogenated hydrocarbons e.g. chloroform and chlorobenzene. Mixtures consisting of a solvent having a boiling point below 90‹ C. and a high boiling solvent having a boiling point above 130‹ C. may also be used. The nitrous acid esters are particularly those of primary or secondary alcohols having 1-10 carbon atoms and may be liquid or gaseous. Suitable organic acids are α-halogenated aliphatic carboxylic acids having 2-6 carbon atoms, preferably polyhalogenated acids e.g. trichloroacetic acid. The pigments produced may be optionally subjected to a heat treatment, either in the solvent in which the process is effected or in a different solvent.
Bibliography:Application Number: DK19700005972