4-[4-(丙烯酰氧基)苯基偶氮]苯磺酸光异构化反应及光聚合水凝胶制备

研究了水溶性偶氮苯单体4-[4-(丙烯酰氧基)苯基偶氮]苯磺酸(APABS)的光物理性质.考察了溶剂对其光异构化反应的影响,并将APABS和丙烯酸羟乙酯(HEA)组成共聚体系,在交联剂N,N-亚甲基双丙烯酰胺(MBAA)的存在下,通过光聚合方法制备水凝胶.利用扫描电子显微镜考察了聚合温度对水凝胶内部结构影响.     

Synthesis and the third-order non-linear optical properties of new azobenzene-containing side-chain polymers

A new series of aromatic azobenzol compounds containing vinyl have been designed as monomers. The azobenzene-containing side-chain polymers containing azo NLO chromophore in each side chain have been synthesized via free radical polymerization. FT-IR, elemental analysis and ¹H NMR were performed to characterize the azo monomers. The molecular weight of the polymers and their distribution were determined by gel permeation chromatography (GPC). The third-order NLO coefficient of azo monomers and their polymers were measured by degenerated four wave mixing (DFWM) technique. As a result, the enhancement of the molecular conjugation and the increase of the NLO chromophore concentration in the molecular chain contribute much to heightening the third-order NLO effect. The electronic effect of substituent on the azobenzol group and the push–pull electronic structure contributes much to enhancing the NLO property.     

Discoloration process modeling by neural network

The photo-oxidation of acid orange 52 dye was performed in the presence of H₂O₂, utilizing UV light, aiming the discoloration process modeling and the process variable influence characterization. The discoloration process was modeled by the use of feedforward neural network. Each sample was characterized by five independent variables (dye concentration, pH, hydrogen peroxide volume, temperature and time of operation) and a dependent variable (absorbance). The neural model has also provided, through Garson Partition coefficients and the Pertubation method, the independent variable influence order determination. The results indicated that the time of operation was the predominant variable and reaction mean temperature was the lesser influent variable. The neural model obtained presented coefficients of correlation on the order 0.98, for sets of trainability, validation and testing, indicating the power of prediction of the model and its character of generalization.     

禁用偶氮染料及其检测标准

本文从发展历史、检测标准、来源和检测原理等方面对偶氮染料进行了论述。     

Synthesis of new 5-thiazolyl azo-disperse dyes for dyeing polyester fabrics

Diazotized aryl amines were coupled with 2-aminothiazoles 1 and 2 to give the corresponding thiazolylazo dyes 3 and 4, respectively. 2-Amino-5-arylazothiazoles 5 reacted with chloroacetyl chloride to afford the chloro-acetamide derivatives 6 which further reacted with 2-mercaptobenzothiazole to furnish a new series of 5-arylazothiazolyl dyes 7. The azo structure of the dyes (rather than the tautomeric hydrazo structure) was assessed by ab initio DFT calculations at the B3LYP/6-31G* level. These dyes were applied to polyester fabric as disperse dyes and their fastness properties were evaluated.     

Simplified Synthesis of the Precursor for the Azo Dye Chlorindazone DS

Recently, Chlorindazone DS 1 has become an important analytical reagent for the detection of gunshot residues from newly introduced ammunition. A simplified synthesis of the precursor of the azo dye 1 , 3‐amino‐6‐chloroindazole ( 2 ), from commercially available 2,4‐dichlorobenzonitrile ( 3a ) has been described. The physical and spectroscopical properties of the known compounds 1 and 2 have been completed. 2‐Chloro‐4‐hydrazinobenzonitrile ( 4a ), 2‐bromo‐4‐hydrazinobenzonitrile (4b) and a new azo dye, 1‐(3′‐chloro‐4′‐cyanobenzene‐1′‐ylazo)‐2‐hydroxynaphthalene‐3,6‐disulfonic acid, disodium salt ( 5 ), have been investigated.     

Ozone,Hydrogen Peroxide/Ozone And UV/Ozone Treatment Of Chromium- And Copper-Complex Dyes: Decolorization And Metal Release

Metal-complex azo dyes constitute a significant fraction of the dyes used in the textile industry and exhibit properties such as superior light- and wash-fastness. While effluent color is not always regulated, the textile finishing industry often decolorizes wastewater using processes including chemical oxidation. In this study, the use of ozone, hydrogen peroxide/ozone and UV/ozone oxidant systems was examined for treatment of two common metal-complex (premetalized) dyes, Acid Black 52 (chromium) and Direct Blue 80 (copper). Oxidant dosages required for decolorization of these dyes were determined. The effect of bicarbonate alkalinity on the ozonation and the hydrogen peroxide/ozone processes also was examined.     

Transformation of Crystal Phase of Micron-sized Rutile TiO2 and Investigation on its Sonocatalytic Activity

The partial transformation of crystal phase of micron-sized TiO₂ powder from rutile to anatase was realized utilizing microwave irradiation in hydrogen peroxide solution. Afterwards, the ultrasound of low power was used as an irradiation source to induce the transition crystal TiO₂ powder to perform the sonocatalytic activity through the degradation of azo fuchsine in aqueous solution. The results show that the sonocatalytic activity of the transition crystal TiO₂ powder is obviously higher than that of pure micron-sized rutile and anatase TiO₂ powders. The degradation ratio of azo fuchsine in the presence of the transition crystal TiO₂ powder attains nearly 80% within 80 min ultrasonic irradiation.     

Degradation of a textile azo dye by pulsed arc discharge to the surface of wastewater

The pulsed arc discharge to the surface of wastewater was applied to the degradation of a textile azo dye (Acid Red 27). A high-voltage electrode (discharging electrode) was vertically placed above the surface of the wastewater while the wastewater itself was grounded. The pulsed arc discharge occurred between the tip of the discharging electrode and the surface of the wastewater, producing various oxidative species. Oxygen was used as the working gas instead of air to prevent nitrogen oxides from forming. The effect of several parameters on the chromaticity and chemical oxygen demand (COD) removal was examined. The results obtained showed that the chromaticity of the wastewater was completely removed by this process and the COD also decreased significantly. It has been found that ozone formed in the gas phase mainly affects the removal of the dye. The contribution of other effects such as ultraviolet light emission and OH radical formation during the arc discharge to the degradation of the dye was found to be less than 15%. For the present reactor system, the optimum pH, pulse repetition rate and agitation speed were found to be 3.0, 110 Hz and 300 rpm, respectively.     

The contribution of biotic and abiotic processes during azo dye reduction in anaerobic sludge

Azo dye reduction results from a combination of biotic and abiotic processes during the anaerobic treatment of dye containing effluents. Biotic processes are due to enzymatic reactions whereas the chemical reaction is due to sulfide. In this research, the relative impact of the different azo dye reduction mechanisms was determined by investigating the reduction of Acid Orange 7 (AO7) and Reactive Red 2 (RR2) under different conditions. Reduction rates of two azo dyes were compared in batch assays over a range of sulphide concentrations in the presence of living or inactivated anaerobic granular sludge. Biological dye reduction followed zero order kinetics and chemical dye reduction followed second-order rate kinetics as a function of sulfide and dye concentration. Chemical reduction of the dyes was greatly stimulated in the presence of autoclaved sludge: whereas chemical dye reduction was not affected by living or gamma-irradiated-sludge. Presumably redox-mediating enzyme cofactors released by cell lysis contributed to the stimulatory effect. This hypothesis was confirmed in assays evaluating the chemical reduction of AO7 utilizing riboflavin, representative of the heat stable redox-mediating moieties of common occurring flavin enzyme cofactors. Sulfate influenced dye reduction in accordance to biogenic sulfide formation from sulfate reduction. In assays lacking sulfur compounds, dye reduction only readily occurred in the presence of living granular sludge, demonstrating the importance of enzymatic mechanisms. Both chemical and biological mechanisms of dye reduction were greatly stimulated by the addition of the redox-mediating compound, anthraquinone-disulfonate. Based on an analysis of the kinetics and demonstration in lab-scale upward-flow anaerobic sludge bed reactors, the relative importance of chemical dye reduction mechanisms in high rate anaerobic bioreactors was shown to be small due to the high biomass levels in the reactors.