Process for the preparation of low-salt, liquid dyestuff preparations
AssigneeBayer Aktiengesellschaft
InventorsPeter Wild, Volker Paulat, Wolfgang Frank, Shaun Murphree
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Abstract
Process for the preparation of low-salt liquid dyestuff preparations, characterized in that they are obtained by: a) diazotization of an aromatic amine, b) 2-fold coupling of the diazo component obtained according to a) to I-acid-urea, in the presence of an inorganic base and in the absence of an organic base, c) desalination and, if appropriate, concentration by means of a pressure permeation of the reaction mixture obtained according to b), so that an inorganic salt content of less than 1% by weight is achieved.
Claims1
Low-salt aqueous dyestuff solution comprising a dyestuff content of 5 to 20% by weight, an inorganic salt content of less than 1% by weight and a content of hydrotropic agents of less than 10% by weight, in each case based on the total amount of the preparation, comprising a dyestuff which, in the form of its free acid, corresponds to the formula (II) ##STR9##
Dependencies are inferred from the claim text.