- Stable diazonium salts of weakly basic amines—Convenient reagents for synthesis of disperse azo dyes
-
A new synthetic strategy for industrially important deep-shade disperse azo dyes was presented in this study. The key procedure is to prepare stable solid diazonium salts of weakly basic amines in the absence of concentrated sulfuric acid. Diazotization by tert-butyl nitrite in ethyl acetate was allowed to proceed in the presence of equivalent 1,5-naphthalenedisulfonic acid as stabilizer of diazonium salts and donor of hydrogen ion for the reaction. The separated solid diazonium salts exhibited good thermal stability. The corresponding disperse azo dyes were subsequently synthesized through the azo-coupling of the prepared solid diazonium salts with a range of aromatic tertiary amines. The azo dyes were produced in short reaction time, excellent yields, mild reaction conditions, simple experimental procedure and low energy consumption.
- Qiu, Jinjing,Tang, Bingtao,Ju, Benzhi,Xu, Yuanji,Zhang, Shufen
-
-
- Clean preparation method for weakly alkaline arylamine azo disperse dye
-
The present invention provides a clean preparation method for weakly alkaline arylamine azo disperse dye. The method is characterized in that when a weakly alkaline arylamine diazonium double salt solid is coupled with a coupling component, the coupling component is pretreated to obtain a fine particle dispersion to be coupled with the weakly alkaline arylamine diazonium double salt; and the generated disperse dye is precipitated from the coupling system and is filtered and dried, thereby obtaining the weakly alkaline arylamine azo disperse dye. According to the preparation method provided by the present invention, by using a stable double salt structure of a diazonium salt, during the coupling, the process of adding acid for dissolution can be omitted; the coupling is performed at the normal temperature, and extra cooling is not required; and the method has a broad application prospect.
- -
-
Paragraph 0047; 0048; 0049; 0050; 0051; 0057; 0058
(2017/01/02)
-