Yellow azo-and azoxystilbene dyes, their preparation and the preparation of storage-stable aqueous concentrates thereof
申请人:Ciba Specialty Chemicals Corporation
公开号:US06491731B1
公开(公告)日:2002-12-10
A mixture of yellow azo- and azoxystilbene dyes having the shade of a C.I. Direct Yellow 11 dye is obtainable from the self-condensation of 4,4′-dinitro-2,2′-stilbenedisulfonic acid in the presence of an alkali metal hydroxide and an excess of formaldehyde beyond that needed for the conversion of 4,4′dinitro-2,2′-stilbenedisulfonic acid to Direct Yellow 6. Concentrated aqueous solutions of the dyes are obtainable by converting the sparingly soluble alkali metal salt of the dye into a water-soluble alkanolammonium salt by a double cation exchange via a lipophilic ammonium salt, in which process the double ion exchange is carried out in a two-phase system of methyl isobutyl ketone/water and using, for the first ion exchange a trialkylamine containing a total of 12 to 40 carbon atoms and, for the second ion exchange, a mono-, di- or trialkanolamine containing 2 to 4 carbon atoms in each alkyl moiety. The dyes are especially useful for dyeing paper.
一种混合黄色偶氮和偶氧基蒽醌染料的混合物,其颜色与C.I.直接黄11染料相同,可通过4,4'-二硝基-2,2'-蒽二磺酸的自缩合在碱金属氢氧化物和超过将4,4'-二硝基-2,2'-蒽二磺酸转化为直接黄6所需的甲醛量的过量甲醛存在下获得。通过将染料的难溶性碱金属盐通过通过脂溶性铵盐的双阳离子交换转化为水溶性脂肪族胺盐,可以获得染料的浓缩水溶液,在该过程中,双离子交换在甲基异丁基酮/水的两相体系中进行,并且对于第一离子交换,使用总碳原子数为12至40的三烷基胺,对于第二离子交换,使用每个烷基部分含有2至4个碳原子的单,二或三烷基醇胺。该染料特别适用于染色纸张。