Synthesis And Industrial Design Of Aromatic Amine Benzothiazole Heterocyclic Azo Disperse Dyes

Heterocyclic disperse dyes,which are considered to be the first choice to replace the anthraquinone disperse dyes with lower color strength and more expensive price,are a type of dyes with heteroatoms in the structure.This type of dye has excellent application properties and has become a more popular field in dye chemistry research.In recent years,with the rapid development of the polyester fiber industry,the continuous improvement of the dyeing process,and the introduction of various dye auxiliaries,people’s requirements for textiles and environmental protection have also continued to increase.Further,in the dyeing and finishing process of polyester and blended fabrics,most of the disperse dyes are dyed in an acid bath,while the pre-treatment desizing,scouring,and alkali reduction processes and the reduction and cleaning after dyeing are performed in alkaline conditions.The dyeing process is more complex,low productivity,and large sewage discharge,which cannot meet the requirements of energy saving,emission reduction,and product quality improvement.Therefore,new-type disperse dyes have received more and more attention from printing and dyeing enterprises because of their advantages of cleaner production,reduced pollution,and lower energy consumption.In this thesis,combined with the research status and market demand of dye chemical enterprises,twelve kinds of aromatic amine benzothiazole heterocyclic azo disperse dyes were synthesized for the purpose of developing high alkali resistance series heterocyclic disperse dyes.These dyes were synthesized by diazotizing-coupling reaction of three benzothiazole compounds as diazonium components and four coupling components.These dyes were characterized by melting point instrument,infrared spectrometer,and nuclear magnetic resonance instrument.Furthermore,the UV-visible spectrum characteristics of twelve dyes and their dyeing properties on polyester fabrics were further studied.The main reports were as follows:1.Synthesis and characterization of three benzothiazole compoundsThree benzothiazole compounds of 2-amino-5,6（6,7）-dichlorobenzothiazole and 2-amino-6-nitrobenzothiazole and 2-amino-6-methoxybenzothiazole were synthesized by thiourea reaction and ring-closure reaction of 3,4-dichloroaniline,p-nitroaniline and p-methoxyaniline.And their yields were all above 90%.And the synthesis of2-amino-5,6（6,7）-dichlorobenzothiazole was taken as an example.The optimal synthesis process conditions of thiourea reaction and ring-closure reaction were explored.These benzothiazole compounds were characterized by melting point instrument,infrared spectrometer,and nuclear magnetic resonance.The results showed that the synthesized benzothiazole compounds were all target products.2.Synthesis and characterization of twelve aromatic amine benzothiazole heterocyclic azo disperse dyesTwelve aromatic amine benzothiazole heterocyclic azo disperse dyes（A₁-A₄,B₁-B₄,C₁-C₄）were synthesized through diazotization-coupling reaction,which the synthesized benzothiazole compounds above were used as diazo components,and the aromatic amine compounds（N-ethyl-N-benzylaniline,N-ethyl-N-p-methylbenzylaniline,N-ethyl-N-p-methylbenzyl-m-toluidine and N-ethyl-N-benzyl-m-toluidine）were used as coupling components.The yields of these dyes were all above 86%.The synthesis of dye A₄was taken as an example.The optimum synthesis conditions were obtained by studying the influence of acidity,diazotization temperature and time,coupling temperature and time on the reaction results.These dyes were characterized by infrared spectrometer and nuclear magnetic resonance.The results showed that the synthesized dyes were all target products.3.Ultraviolet-visible spectroscopy study of twelve aromatic amine benzothiazole heterocyclic azo disperse dyesThe maximum visible absorption wavelength of the dyes was determined in acetone,DMF,and ethylene glycol monoethyl ether solvents,respectively.The molar absorption coefficient was calculated according to Lambert-Beer’s law formula.The maximum absorption wavelengths of these dyes in the three solvents were 504.0-550.0 nm,515.0-561.0nm and 513.0-555.5 nm,respectively.And theεof these dyes in solvents were basically more than 40,000 L·mol^-1·cm^-1,and even some dyes were more than 50,000 L·mol^-1·cm^-1.4.Dyeing properties of twelve aromatic amine benzothiazole heterocyclic azo disperse dyesThe dyeing properties of twelve dyes on the polyester fabric were studied by high temperature and high-pressure dyeing.The color light and color fastness of the dyed polyester fabric was investigated,as well as the dyeing properties of dyes such as the dispersibility,dispersity,dyeing rate,lifting power,alkali resistance,and oxygen bleaching resistance.The results showed that all the dyes had excellent color fastness,the dispersity and diffusion property of dyes were above grade 4,and the dyeing rate of dyes was up to 95%.Stable color can be obtained when these dyes were dyed in a wide p H range.Some dyes are even dyed in a bath of 16 g/L Na OH and 15 g/L H₂O₂,and the color does not change.5.Industrial design of an annual output of 3600 tons of heterocyclic azo disperse dyesAccording to the supply and demand of high alkali-resistant disperse dyes in the market,the dye A₄was taken as an example,the industrial design with an annual output of 3600 t/a was carried out.The industrial process design in this thesis was mainly divided into four sections:intermediate section,diazo chemical section,coupling section,and post-treatment section.The main equipment such as pump,stirred tank reactor,spray drying system and sanding system were designed and selected,and the models and materials of the key equipment were determined.At the same time,this thesis also carried out the material balance and heat balance.Auto CAD was used to draw the main equipment diagram and process flow chart and other related drawings.Reasonable requirements for comprehensive utilization and reliability in the production process were put forward.Finally,the corresponding economic estimates of this design are given,in which the investment profit rate is up to 42.35%and the investment tax rate is up to 19.81%,both are higher than the average level of the dye industry.