| 摘要 |
<p>1,266,489. Nitrated azo dyestuff carboxylic acids. CIBA-GEIGY A.G. 3 June, 1970 [30 June, 1969], No. 26781/70. Heading C4P. Nitrated azo dyestuff carboxylic acids of formula where R is the residue of a diazo component are produced by treating an azo dyestuff of formula with a nitrating agent. The group R is, in particular a benzene residue which may contain substituents. The nitrated azo dyestuffs produced are used as intermediates in the production of pigments derived from 6-nitro-2,3- hydroxy naphthoic acid, e.g. by conversion to the acid chloride followed by condensation with a base, for example 4-benzoylamino-1-amino benzene. Nitration is carried out with nitric acid or a mixture of nitric and sulphuric acid. The nitrating mixture is added to a solution of the dyestuff, preferably a sulphuric acid solution and nitration is carried out below 20‹ C.</p> |
