C - Chemistry – Metallurgy – 09 – B
Patent
C - Chemistry, Metallurgy
09
B
260/236.18, 260/
C09B 57/00 (2006.01) C09B 11/24 (2006.01)
Patent
CA 1064916
Abstract of the disclosure: A process for the preparation of xanthene dyestuffs of the general formula Image , (in which R1 and R2 are identical or different, each re- presenting an optionally substituted aliphatic or op- tionally substituted araliphatic or cycloaliphatic radical, or R1 represents also a hydrogen atom or a carbocyclic aromatic or heterocyclic radical, or R1 and R2 together with the N-atom form a heterocyclic radical optionally containing further hetero-atoms, the benzene nucleus A may optionally contain substituents, and m stands for the integer 1,2, 3, 4 or zero) had been found wherein the inner salt of a 3,6-dihalogeno-9-(2'-sulfophenyl)-xanthene- 9-ol of the formula Image (in which X stands for a halogen atom and A has the above- mentioned meaning) is reacted with a primary or secondary amine of the formula Image , (in which R1 and R2 have the meanings specified as above) in a polar solvent which is free from acid groups; to obtain the sulfo compounds, the product is subsequently sulfonated. The improvement in this process is to carry out the reaction of the xanthenol with the amine in stoichio- metrical amounts and in the presence of an inorganic acid- binding agent and/or an acid-binding tertiary aliphatic or cycloaliphatic amine, of pyridine or of a pyridine deri- vative. The novel process has the advantage of yielding dyestuffs of high quality with a strong color intensity and brilliancy, a high fastness to light and a uniform dyeing behaviour. Furthermore, the dyestuffs are obtained in very good yields avoiding the high charge of the waste water of present processes of the dyestuff itself or its starting components used in excess.
242170
Hahnke Manfred
Kohlhaas Folker
Meininger Fritz
Papenfuhs Theodor
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