71494-73-0Relevant academic research and scientific papers
An intramolecular Mannich type reaction of ortho-amino aromatic azo dye and its detection effect for formaldehyde
Chen, Weiguo,Cui, Zhihua,Gao, Pu,Jiang, Hua
, (2020)
A series of aromatic primary amine dyes were designed and applied for the modification of silk fibroin with Mannich-type reaction in the previous studies. Most aromatic primary amine dyes achieved the expected results with the participation of formaldehyde. However, those azo dyes with ortho-amino aromatic structure lost their colour and did not have any modification on silk fibroin under the same conditions of treatment. Therefore, the decolorization phenomenon of ortho-aniline aromatic azo dyes was analyzed using FT-IR, ESI-MS, NMR and Gaussian computation and the results indicated that an intramolecular Mannich reaction occurred between ortho-amino aromatic azo dyes and formaldehyde. In addition, a secondary effect of reduction of dyes by formaldehyde took place, in which the conjugated chromogenic system of the dye molecules was destroyed, producing benzimidazole, o-phenylenediamine and nitrogen-containing heterocyclic substances with polymethyl substitution. This decolorization of dye was studied as a detection or monitoring method for formaldehyde, and it showed advantages of sensitive response, clear visual indication, and no volatilization of organic solvent.
A novel reactive dyeing method for silk fibroin with aromatic primary amine-containing dyes based on the Mannich reaction
Chen, Weiguo,Gao, Pu,Jiang, Hua,Cui, Zhihua
, p. 300 - 310 (2019/05/14)
Chemical modification of silk fibroin is a useful method for improving its performance. There are many existing methods of protein modification, some of which are limited for application to silk by the disadvantages of severe reaction conditions, poor reaction selectivity and problems with characterization of the product. In this paper, a series of dyes containing aromatic primary amine groups was designed and synthesized for modification of silk fibroin via the Mannich reaction. This three-component Mannich modification showed several advantages, such as mild reaction conditions, good selectivity, easy characterization and high fastness. In particular, the degree of modification could be established visually according to the color yield and the color fixation on silk fibroin. Therefore, the Mannich reaction of silk with dyes containing aromatic primary amine groups may become a novel reactive dyeing method. Studies of structure-performance relationships showed that suitable dyes for dyeing of silk should meet the following criteria: (1)High nucleophilicity of the aromatic primary amine group. (2)No high electron cloud density center around the amino group.
