申请人:Hoechst Aktiengesellschaft
公开号:US04115380A1
公开(公告)日:1978-09-19
Process for the manufacture of a disazo dyestuff of the formula ##STR1## in which R.sub.1 and R.sub.2 each stand for hydrogen, chlorine, bromine, alkyl of 1 to 4 carbon atoms or alkoxy of 1 to 4 carbon atoms, R.sub.3 and R.sub.4 each stand for hydrogen, chlorine, bromine, nitro, trifluoromethyl, alkyl of 1 to 4 carbon atoms or alkoxy of 1 to 4 carbon atoms; and the hydroxyl groups each stand in 2- or 4-position to the azo groups which comprises diazotizing a 2- or 4-hydroxy-4'-aminoazobenzene of the formula ##STR2## in which R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are defined as above, with an alkali metal nitrite in an aqueous mineral acid, the normality of which being about 10.sup.-2 to 5, in the presence of a phenol capable of being coupled of the formula ##STR3## in which R.sub.1 and R.sub.2 are defined as above and subsequently reacting the diazonium salt obtained with the phenol by raising the pH to a value between about 3 and 11, the surprising feature of this process (diazotization in the presence of the phenol) being that practically no nitrozation or a nitration of the phenol occurs.
制备公式为##STR1##的二氮基染料的制备方法,其中R.sub.1和R.sub.2分别表示氢、氯、溴、1至4个碳原子的烷基或1至4个碳原子的烷氧基,R.sub.3和R.sub.4分别表示氢、氯、溴、硝基、三氟甲基、1至4个碳原子的烷基或1至4个碳原子的烷氧基;并且羟基分别位于离子偶联基的2-或4-位。该方法包括在碱性金属亚硝酸盐存在下,以约10.sup.-2至5的浓度,在水溶矿酸中重氮化公式为##STR2##的2-或4-羟基-4'-氨基偶氮苯,其中R.sub.1、R.sub.2、R.sub.3和R.sub.4如上所定义,并在pH值在约3至11之间的条件下,将所得的重氮盐与公式为##STR3##的离子偶联剂反应。该方法的惊人特点(重氮化在离子偶联剂存在下)是几乎不会发生对离子偶联剂的亚硝化或硝化反应。