Synthesis And Dyeing Performance Of Di-methyl Azo Disperse Dyes

A kind of di-methyl azo disperse dyes have been intensively researched to produce high molar extinction coefficient, bright colour shade and excellent washing fastness on polyester fibers, It is a practical significance to expand the application scope of disperse dyes. Two di-methyl amines were prepared as coupling components, three aromatic amines as diazo components, six di-methyl azo disperse dyes were synthesized by diazotization and coupling reaction. Moreover, they were all confirmed by IR,’H NMR and elementary analysis. The dyeing performances were assessed on polyester fiber, ethylated fir powder and benzylated fir powder. Four main points were reported as follows:1、The synthesis and characterization of the two di-methyl aminesIn the present of PEG-400as catalyst and sodium carbonate as the deacid reagent,2-N,N-bis(methyl acetate)amino-4-acetamido anosole and3-N,N-bis(methyl acetate) acetamido aniline were prepared by bi-molecular substitution reaction, the2-amino-4-acetamido anosole and3-acetamido aniline with methyl chloroacetate. The yields of the two di-methyl amines were92.0%and94.4%, the purity of them were95.4%and98.4%. The structures of the di-methyl amines were characterized by1H NMR, IR, and EA.2、Synthesis and characterization of the six di-methyl azo disperse dyesUsing the above two di-methyl amines as coupling components,4-nitroaniline,2,4-dinitro-6-bromineaniline and2-amino-3,5-dinitrothiopHene as diazo components, six di-methyl azo disperse dyes AiBi-A2B3were prepared via the diazo-coupling reaction, the yields of dyes were all above87%, the purity of the dyes were all over96%, the melting points were all above184℃and the Rf value were0.74-0.84. The six di-methyl azo disperse dyes were also confirmed by IR,1H NMR and EA.3、The UV-visible absorption analysis of the six di-methyl azo disperse dyesThe maximum absorption of the prepared azo compounds disperse dyes were from480to609nm in DMF and the values of the molar extinction coefficient were in the range of1.2×104-3.4×104. Furthermore, to the same diazo components, when the OCH3were introduced to the coupling components, the maximum absorption were go up; to the same components, when the withdrawing groups like NO2were introduced in the diazo components, the obvious bathochrom of the maximum wavelength will occur. And, the rate of the maximum wavelength of the heterocyclic di-methyl azo disperse dyes were higher than others.4、The dyeing performance of the six di-methyl azo disperse dyesThe dyeing performance of the synthesized azo disperse dyes were evaluated on polyester fiber, ethylated fir powder and benzylated fir powder. The result showed that the colour shade (A1B1～A2B3) are pink, bright blue, green, orange, violet and blue on polyester fiber. The dyebath exhaustion percentage was ranged from16.1%to96.1%, furthermore, the washing fastness was4-5and the light fastness was5～6. Which indicated that the dyes on fibers were found to show bright colour shade, high percentage of dye exhaustion and excellent washing fastness. Furthermore, the dyed ethylated fir powder and benzylated fir powder were found to show the similar color shade, their dyebath exhaustion percentage were higher than dyed polyester fiber’s but their washing fastness are not as good as the dyed fibers. It reveals that the prepared azo disperse dyes can not be only applied to the polyester fiber, but ethylated fir powder and benzylated fir powder.In the thesis, a kind of di-methyl azo disperse dyes were found to show bright colour shade, high intensity of absorption and excellent light fastness. They can enrich the colour gamut of azo disperse dyes with di-methyl and expand the application of azo disperse in wood dyeing. Moreover, the encouraging results are important in theory and practical uses for developing the new kind disperse dyes and dyeing on modified wood.