- The Photochemistry of Metanilic Acid: Photoisomerization and Photodegradation
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In the photolysis of sodium metanilate (1,Na) a single triplet and a series of ?-complexes give rise to the isomeric aniline sulphonic acids (2) and (3) and aniline (4).
- Lally, John M.,Spillane, William J.
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- Modification of activated carbons based on diazonium ions in situ produced from aminobenzene organic acid without addition of other acid
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Activated carbon products modified with a benzene sulfonic acid group were prepared based on the spontaneous reduction of diazonium salts in situ generated in water without addition of an external acid. The diazotization reaction assisted by the organic acid substituent, produced at once amine, diazonium and triazene functionalities that maximize the grafting yield by a chemical cooperation effect.
- Lebegue, Estelle,Madec, Lenaic,Brousse, Thierry,Gaubicher, Joel,Levillain, Eric,Cougnon, Charles
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- Conjugated Microspheres FeTCPP–TDI–TiO2 with Enhanced Photocatalytic Performance for Antibiotics Degradation Under Visible Light Irradiation
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Abstract: Toluene disocyanate (TDI) was used as a bridging molecule, a bridge bonding conjugated microsphere (FeTCPP–TDI–TiO2) was successfully prepared by grafting tetra-(carboxyphenyl) porphyrin iron (FeTCPP) on the surface of TiO2 microspheres. The FT-IR spectra revealed that the hydroxyl group (–OH) of TiO2 microspheres surface and the carboxyl group (–COOH) of FeTCPP reacted respectively with the active isocyanato groups (–NCO) of TDI to form a surface conjugated microsphere FeTCPP–TDI–TiO2. The UV–vis DRS analysis demonstrated that the formation of FeTCPP–TDI–TiO2 extended remarkably the photoresponse of as-prepared samples to visible light region. The photocatalytic activity of FeTCPP–TDI–TiO2 was evaluated using the photocatalytic degradation of norfloxacin (NFC), tetracycline (TC) and sulfapyridine (SPY) antibiotics in aqueous solution under visible-light irradiation. The results showed that, TDI, as a bond unit, was used to form a steady chemical bridging bond linking between FeTCPP and the surface of TiO2 microspheres, and the prepared catalyst exhibited higher photocatalytic activity under visible-light irradiation for antibiotics degradation in comparison with P25. The degradation of antibiotics all followed the pseudo first-order reaction model under visible light irradiation, and the degradation mechanisms of NFC, TC and SPY were also proposed. Graphical Abstract: [Figure not available: see fulltext.]
- Yao, Binghua,Peng, Chao,He, Yangqing,Zhang, Wen,Zhang, Qinku,Zhang, Ting
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- Synthesis and characterization of polyaniline/nickel oxide composites for fuel additive and dyes reduction
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Polyaniline (PANI) and Polyaniline/Nickel oxide (PANI/NiO) composites are prepared to use as a potential catalyst, by Chemical oxidation method using ammonium persulfate (NH4)2S2O8)) as an oxidant. Nickel oxide (NiO) nanopartiles are prepared by Sol-gel method. The synthesized products were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction technique (XRD). The prepared PANI/NiO composites are used as additive with different concentrations in diesel to investigate their efficiency as fuel additive. The catalytic properties are studied by using the synthesized products as catalyst for reduction of dyes in aqueous media. Sodium borohydride (NaBH4) is used as reducing agent. Linear relationships are obtained between time and ln(A0/At) for Methyl orange and Methylene blue. Kapp values were obtained for three catalysts showed the increasing trend of reduction for both dyes as, PANI NiO PANI/NiO composites. Experimental data analysis proved PANI/NiO composites to be efficient catalysts and fuel additive as compared to PANI and NiO.
- Jamil, Saba,Ahmad, Zunaira,Ali, Muhammad,Rauf Khan, Shanza,Ali, Sarmed,Amen Hammami, Mohamed,Haroon, Muhammad,Saleh, Tawfik A.,Ramzan Saeed Ashraf Janjua, Muhammad
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- Novel Biomass-Derived Fe3O4@Pd NPs as Efficient and Sustainable Nanocatalyst for Nitroarene Reduction in Aqueous Media
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Abstract: A novel magnetically recyclable nitrogen-doped Fe3O4@Pd NPs was prepared from the biomass-based materials which was employed as carbon and nitrogen source. The as-prepared catalysts were fully characterized by a variety of physicochemical techniques and were exploited for nitroaromatic hydrogenation with broad scope and excellent chemoselectivity using molecular hydrogen as a reductant. The heterogeneous catalysts can be recovered easily and reused for at least eight recycling reactions without obviously loss of catalytic properties. In addition, using this protocol, the key intermediate of marketed drug Osimertinib could be synthesized easily. Graphical Abstract: [Figure not available: see fulltext.].
- Zhao, Linwei,Zheng, Kai,Tong, Jianying,Jin, Jianzhong,Shen, Chao
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- Palladium nanoparticles produced and dispersed by Caldicellulosiruptor saccharolyticus enhance the degradation of contaminants in water
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This study focused on examining the general applicability of coupling bio-palladium (Pd) nanoparticle generation and bio-H2 produced by Caldicellulosiruptor saccharolyticus for wastewater treatment under extreme thermophilic conditions. Na2PdCl4 was added to cell cultures to achieve a final Pd concentration of 50 mg L-1. Methyl orange (MO) and diatrizoate were chosen as the contaminants in water. In the cultures with, and without, Pd added, MO (100 mg L-1) was degraded within 30 min and in over 6 h, respectively. Diatrizoate (20 mg L-1) was degraded within 10 min in Pd-added cultures. However, no diatrizoate degradation happened without Pd addition. The degradation rates were correlated positively with dissolved hydrogen generated by C. saccharolyticus. Furthermore, the catalytic actions of Pd(0) nanoparticles and cells were distinguished during the degradation process. MO was degraded under the combined action of Pd(0) and hydrogenase. However, Pd(0) was the essential catalyst, and hydrogenase had no effect on the deiodination of diatrizoate within 20 min. Pd(0) particles were dispersed well by the cells of C. saccharolyticus and showed a better catalytic activity than Pd(0) formed without cells. Dissolved hydrogen produced by C. saccharolyticus should be the perfect reduction equivalent for Pd formation and for reducing degradation. Therefore, Pd should be added to C. saccharolyticus cultures to enhance the degradation of contaminants in water. This journal is
- Shen, Nan,Xia, Xiu-Yang,Chen, Yun,Zheng, Hang,Zhong, Yong-Chen,Zeng, Raymond J.
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- Reduction of azo dyes with zero-valent iron
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The reduction of azo dyes by zero-valent iron metal (Fe0) at pH 7.0 in 10 mM HEPES buffer was studied in aqueous, anaerobic batch systems. Orange II was reduced by cleavage of the azo linkage, as evidenced by the production of sulfanilic acid (a substituted aniline). Adsorption of the dyes on iron particles was less than 4% of the initial concentration, and >90% mass balance was achieved by summing aqueous concentrations of dye and product amine. All of the 9 azo dyes tested were reduced with first-order kinetics. The kinetics of decolorization at the λ(max) of each dye were rapid: a typical k(obs) was 0.35 ± 0.01 min-1 for Orange II at 130 rpm on an orbital shaker, corresponding to a surface area normalized rate constant (k(SA)) of 0.21 ± 0.01 L m-2 min-1. The rate of reduction of Crocein Orange G varied with initial dye concentration in a way that suggests saturation of surface sites on the Fe0, and varied with the square-root of mixing rate (rpm) in a manner indicative of mass transfer limited kinetics. Correlation analysis using k(obs) for all of the azo dyes, estimates of their diffusion coefficients, and calculated energies of their lowest unoccupied molecular orbitals (E(LUMO)), gave no strong trends that could be used to derive structure-activity relationships. Using an authentic sample of wastewater from a dye manufacturing operation and construction-grade granular Fe0, rapid decolorization was achieved that was consistent with reduction of azo dyes. (C) 2000 Elsevier Science Ltd. The reduction of azo dyes by zero-valent iron metal (Fe0) at pH 7.0 in 10 mM HEPES buffer was studied in aqueous, anaerobic batch systems. Orange II was reduced by cleavage of the azo linkage, as evidenced by the production of sulfanilic acid (a substituted aniline). Adsorption of the dyes on iron particles was less than 4% of the initial concentration, and >90% mass balance was achieved by summing aqueous concentrations of dye and product amine. All of the 9 azo dyes tested were reduced with first-order kinetics. The kinetics of decolorization at the λmax of each dye were rapid: a typical kobs was 0.35±0.01 min-1 for Orange II at 130 rpm on an orbital shaker, corresponding to a surface area normalized rate constant (kSA) of 0.21±0.01 L m-2 min-1. The rate of reduction of Crocein Orange G varied with initial dye concentration in a way that suggests saturation of surface sites on the Fe0, and varied with the square-root of mixing rate (rpm) in a manner indicative of mass transfer limited kinetics. Correlation analysis using kobs for all of the azo dyes, estimates of their diffusion coefficients, and calculated energies of their lowest unoccupied molecular orbitals (ELUMO), gave no strong trends that could be used to derive structure-activity relationships. Using an authentic sample of wastewater from a dye manufacturing operation and construction-grade granular Fe0, rapid decolorization was achieved that was consistent with reduction of azo dyes.
- Nam, Sangkil,Tratnyek, Paul G.
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- Degradation of cationic and anionic dyes in coagulation-flocculation process using bi-functionalized silica hybrid with aluminum-ferric as auxiliary agent
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Cationic dye (methylene blue) and anionic dye (methyl orange) degradation in the coagulation process was demonstrated. The key material was a natural coagulant-laterite soil dominated by a silica component, while aluminum-ferric ions acted as an auxiliary agent in the degradation process. Charge neutralization, electrical double layer compression and sweeping flocculation were the mechanisms in the decolorization reaction. These results provided a new insight into effective dye degradation using a new class of natural coagulant-natural resources (laterite soil). The complex molecular structure of methylene blue and methyl orange was degraded into smaller hydrocarbon forms, accompanied by the formation of silsesquioxane. The silsesquioxane was the final product of degradation with promising flocculation and low volume sludge. Lastly, a comparison of the aluminum-based coagulant and a laterite soil natural coagulant shows a clear vision of the performance for both types of coagulant.
- Lau, Yen-Yie,Wong, Yee-Shian,Teng, Tjoon-Tow,Morad, Norhashimah,Rafatullah, Mohd,Ong, Soon-An
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- Homogeneous palladium nanoparticles surface hosts catalyzed reduction of the chromophoric azo (-N=N-) group of dye, acid orange 7 by borohydride in alkaline media
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In alkaline media, well-characterized gelatin-stabilized palladium (GPd) nanoparticles catalyze the reduction of the azo group containing pollutant dye, Acid Orange 7 (AO7) by sodium borohydride (NaBH4) to 1-amino-2-napthol and sulfanilic acid. Kinetic observations and detailed FTIR studies suggests that the reaction follows Langmuir-Hinshelwood kinetic model, where during the reaction both AO7 and borohydride are adsorbed on the GPd surface. Plots of lnko versus ln[AO7] or ln[NaBH4] show that the order of reaction with respect to AO7 and NaBH4 remains almost same over different molar ratios of [NaBH4]/[AO7]. The catalyzed reaction shows an initial induction period (t0) due to a surface-restructuring process of GPd nanoparticles, and (1/t0) can be defined as the rate of surface restructuring. The activation energy of the catalyzed reaction and energy of the surface-restructuring process of GPd are estimated as 22 ± 3 and 25 ± 7 kJ M-1, respectively.
- Das, Ranendu Sekhar,Singh, Bula,Mandal, Arabinda,Banerjee, Rupendranath,Mukhopadhyay, Subrata
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- Photolysis and photocatalytic decomposition of sulfamethazine antibiotics in an aqueous solution with TiO2
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Photo-decomposition of sulfamethazine (SMT) involves photolytic and photo-catalytic reactions, which occur simultaneously. The relative contributions of these two reactions to the overall SMT photo-decompositions by TiO2 and the intermediates of SMT photo-decompositions were systematically examined with the effects of TiO2 loading, and the pH and the initial SMT concentrations in the solutions. The apparent rate constants of SMT photo-decomposition reactions, which were well described by the pseudo-first-order kinetic model, ranged from 0.24 to 1.61 h-1. The overall photo-decomposition efficiencies of 0.072 mM SMT were the highest at pH 5.5 with 0.5 g L-1 TiO2 due to the adsorption-induced photocatalytic decomposition of SMT on TiO2. However, the SMT photolysis occurred more rapidly at pH 10. Two reactive species of holes and hydroxyl radicals concurrently participated in the photocatalytic decomposition of SMT, and the latter dominated the oxidative reactions of SMT on TiO2. Eight intermediates of SMT photo-decomposition were determined using LC-MS. Their time-dependent distributions indicated that the photo-decomposition of SMT was triggered by hydroxylation on aniline and dimethylpyrimidinyl moieties, followed by the cleavage of the S-N bond of SMT. Our results illustrated that the intermediates with dimethylpyrimidinyl groups possess strong resistance to photo-decomposition and played a determinant role in the photo-decomposition of SMT.
- Tzeng, Tai-Wei,Wang, Shan-Li,Chen, Chiing-Chang,Tan, Chen-Chung,Liu, Yu-Ting,Chen, Tsan-Yao,Tzou, Yu-Min,Chen,Hung
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- Cyan color-emitting nitrogen-functionalized carbon nanodots (NFCNDs) from Indigofera tinctoria and their catalytic reduction of organic dyes and fluorescent ink applications
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The present study reports the synthesis of nitrogen-functionalized carbon nanodots (NFCNDs) by a low-cost hydrothermal method using the leaf extract of Indigofera tinctoria as a novel carbon precursor. The synthesized NFCNDs were characterized by diverse spectroscopic techniques. The optical properties of N-CNDs were analyzed by UV-visible and fluorescence spectroscopic studies. The quantum yield (QY) for the prepared NFCNDs was found to be 12.6%. The surface morphology, functional groups, and crystallinity of NFCNDs were evaluated by HR-TEM, FT-IR, XRD and Raman spectroscopic methods, respectively. The Raman results revealed the moderate graphite structure of NFCNDs, and the calculated ID/IG value was 0.49. The spherical appearance of the synthesized NFCNDs was confirmed by HR-TEM, and the calculated size of the NFCNDs was 4 nm. The XRD and SAED pattern results gives an evidence for the amorphous nature of the prepared NFCNDs. The thermal stability of NFCNDs was studied by TGA analysis. The resulting NFCNDs acted as a green nanocatalyst and thus efficiently improved the reducing capability of sodium borohydride (NaBH4) in the catalytic reduction of methylene blue (MB) and methyl orange (MO) dyes. Furthermore, the bright cyan emission characteristics of synthesized NFCNDs were utilized as a labeling agent in anti-counterfeiting applications.
- Abirami, Natarajan,Arul, Velusamy,Arulmozhi, Rajaram,Kavitha, Ganesan,Vinoth Kumar, Jothi
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- Zwitterionic buffer-induced visible light excitation of TiO2 for efficient pollutant photodegradation
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Excitation of TiO2 for visible light absorption by surface complexation with antenna organic molecules is an effective strategy to improve its solar utilization efficiency for photocatalytic application, but the existing antenna molecules are mostly toxic and environmentally-aggressive, severely limiting their practical application. In this study, we tested the potential of zwitterionic buffers (Good's buffers) as an environmentally-benign alternative. The addition of Good's buffers significantly enhanced methyl orange (MO) photodegradation by TiO2 under visible light, but the enhancement degree varied with the different buffer types, buffer concentration and solution pH. The presence of 4-(2-hydroxyerhyl) piperazine-1-erhanesulfonic acid (HEPES) as a typical Good's buffer led to over 90% MO removal within 180 min, whereas only slight MO removal was observed in the TiO2 alone system during the same period. Such an induced visible light photocatalytic activity was attributed to a complexation between the conjugate acid structured buffer molecule and TiO2, which favors a ligand-to-metal charge transfer (LMCT). The LMCT activity was strongly dependent on the molecule structure, especially the states of hydroxyl and amino groups of Good's buffers. The pH buffering ability of the buffers also contributed to the efficient MO photodegradation. This study suggests a great potential of Good's buffers as both green antenna molecules and pH buffer for strengthening TiO2-based photocatalytic remediation processes.
- Xiao, Xiang,Zhu, Wen-Wen,Lei, Yu-Bin,Liu, Qiu-Yue,Li, Qian,Li, Wen-Wei
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- Scale-up synthesis of zero-valent iron nanoparticles and their applications for synergistic degradation of pollutants with sodium borohydride
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The scale-up synthesis of nZVI (zero-valent iron nanoparticles) was optimized by response surface modeling (RSM). The synthesized nZVI was employed for synergistic degradation of metronidazole (MNZ) or methyl orange (MO) in the presence of sodium borohydr
- Ravikumar,Dubey, Swati,pulimi, Mrudula,Chandrasekaran, Natarajan,Mukherjee, Amitava
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- Preparation method of p-amino benzene sulfonic acid
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The invention discloses a preparation method of p-amino benzene sulfonic acid. The preparation method comprises the following steps: respectively pumping aniline and concentrated sulfuric acid into a mixer provided with a heat exchange device according to a certain proportion, mixing to form salt, feeding the prepared liquid aniline sulfonate into a negative pressure environment, heating, and carrying out transposition dehydration to prepare the p-amino benzene sulfonic acid, wherein the operation cycle of the preparation method is 1.5-3 hours/batch. The p-aminobenzene sulfonic acid provided by the invention exports heat released in the salifying process to obtain liquid-state stable aniline sulfonate, and in the subsequent transposition reaction process, water vapor generated by dehydration is discharged out of the system by utilizing a vacuum negative pressure environment, so that a p-amino benzene sulfonic acid crude product with a good condition is obtained. The preparation method has the characteristics of good production environment, high safety performance, short production period, high yield, complete aniline reaction and the like, and is suitable for popularization and application.
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Paragraph 0042; 0045-0048; 0051-0053
(2021/07/17)
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- Cornforth and Corey-Suggs reagents as efficient catalysts for sulfonation of aromatic and heteroaromatic compounds using NaHSO3 under solvent free and microwave conditions
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Cornforth and Corey-Suggs reagents Pyridinium Dichromate (PDC) and Pyridinium Chlorochromate (PCC) were explored as efficient catalysts for sulfonation of aromatic and heteroaromatic compounds using NaHSO3 in aqueous acetonitrile medium at room temperature within 1–4 h, while microwave assisted reactions took place within 1–4 min under solvent-free conditions. These observations indicate significant rate accelerations in microwave assisted reactions. which were explained due to the bulk activation of molecules induced by insitu generated high temperatures and pressures when microwaves are transmitted through reaction medium.
- Fatima, Touheeth,Duguta, Govardhan,Purugula, Venkanna,Yelike, Hemanth Sriram,Kamatala, Chinna Rajanna
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p. 1001 - 1006
(2020/07/27)
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- The performance and degradation mechanism of sulfamethazine from wastewater using IFAS-MBR
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Sulfamethazine (SMZ) is an important sulfonamide antibiotic. Although the concentration in the environment is small, it is harmful. The drug residues can be transferred, transformed or accumulated, affecting the growth of animals and plants. In this study, the integrated fixed-film activated sludge membrane bioreactor (IFAS-MBR) were constructed to investigate the performance and degradation mechanism of SMZ. The addition of SMZ had a significant impact on the removal of the chemical oxygen demand (COD) and ammonia nitrogen (NH4 +-N). The optimal operating conditions were hydraulic retention time (HRT) at 10 h and solid retention time (SRT) at 80 d, respectively. On this basis, the effects of different SMZ concentrations on nutrient removal, degradation, and sludge characteristics were compared. The removal efficiency of SMZ increased with the increase of SMZ concentration. The maximum removal rate was as high as 87%. The SMZ dosage also had an obvious effect on sludge characteristics. As the SMZ concentration increased, the extracellular polymer substances (EPS) concentration and the membrane resistance both decreased, which were beneficial for the reduction of membrane fouling. Finally, seven kinds of SMZ biodegradation intermediates were identified, and the possible degradation pathways were speculated. The microbial community results showed that the microbial diversity and richness in the reactor decreased after adding SMZ to the influent. The relative abundance of Bacteroidetes, Actinobacteria, Saccharibacteria and Nitrospirae increased at the phylum level. Sphingobacteria and Betaproteobacteria became dominant species at the class level. The relative abundance of norank-p-Saccharibacteria and Nitrospirae increased significantly, and norank-p-Saccharibacteria may be the dominant bacteria for SMZ degradation.
- Hou, Huanhuan,Duan, Liang,Zhou, Beihai,Tian, Yuan,Wei, Jian,Qian, Feng
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supporting information
p. 543 - 546
(2019/09/07)
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- Effects of water environmental factors on the photocatalytic degradation of sulfamethoxazole by AgI/UiO-66 composite under visible light irradiation
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It is necessary to find visible light responsive photocatalysts for rapid and simple degradation of organic pollutants in water environment. In this work, a visible light responsive composite photocatalyst AgI/UiO-66 was prepared by an in situ growth method. Sulfamethoxazole (SMZ) antibiotic was selected as the target contaminant to probe the photocatalytic performance of the as-prepared AgI/UiO-66 composite under visible light irradiation. The results showed that the photocatalytic performance of the AgI/UiO-66 composite enhanced significantly compared to pure AgI. The effects of typical environment factors (i.e. pH, inorganic salt ions and common anions) on the degradation of SMZ were evaluated extensively. Results showed that the investigated pH (5.2, 7.0, 9.5) had no apparent effect on the photocatalytic degradation of SMZ except pH 2.5, at which the degradation rate of SMZ decreased significantly. In addition, inorganic salt ions and Cl?, HCO3? and SO42? anions in water exhibited no apparent effect on the degradation of SMZ. The effect of water matrix on the degradation of SMZ was also investigated. In the river water, the removal efficiency of SMZ was reduced compared with the cleaner water matrix. The capture experiments of radicals confirmed that superoxide radicals ([rad]O2?) and hydroxyl radicals ([rad]OH) were the main active species for the photocatalytic degradation of SMZ in the present work. Finally, the tentative degradation pathways of SMZ were proposed based on the intermediates analysis.
- Wang, Chao,Xue, Yao,Wang, Peifang,Ao, Yanhui
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p. 314 - 322
(2018/03/22)
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- Synthesis method of pharmaceutical intermediate p-aminobenzenesulfonic acid
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The invention relates to a synthesis method of a pharmaceutical intermediate p-aminobenzenesulfonic acid. The synthesis method mainly comprises: adding 3 mol 4-aminophenol, 4-5 mol 2-sulfonic toluene,and 10-16 g of aluminum chloride powder to a reaction container, heating the solution to a temperature of 90-110 DEG C, carrying out thermal insulation for 80-120 min, cooling the solution to a temperature of 10-15 DEG C, adding 2 L potassium bromide solution, crystallizing, filtering, dissolving the crystal in a potassium carbonate solution, cooling the solution to a temperature of 5-8 DEG C, crystallizing, filtering to obtain a crystal, washing with a potassium bromide solution, washing with a triethylamine solution, washing with a nitromethane solution, dewatering with a dewatering agent,and drying at a temperature of 110-115 DEG C to obtain the finished product p-aminobenzenesulfonic acid.
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Paragraph 0014; 0015
(2018/09/11)
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- Facile fabrication of γ-Fe2O3-nanoparticle modified N-doped porous carbon materials for the efficient hydrogenation of nitroaromatic compounds
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Novel γ-Fe2O3-nanoparticle (NP) modified N-doped porous carbon materials (γ-Fe2O3/mCN) were prepared by one-pot pyrolysis of a mixture of melamine, polyacrylonitrile, and FeCl3·6H2O at different temperatures. At a pyrolysis temperature of 900 °C, γ-Fe2O3/mCN-900-20 exhibited a high surface area and a N content of 8.47%, caused by the complete pyrolysis of melamine and polyacrylonitrile at 900 °C. The obtained material γ-Fe2O3/mCN-900-20 was used as a cost-effective catalyst for the hydrogenation of nitrobenzene using N2H4·H2O as the reductant under mild reaction conditions. As compared to other catalysts (e.g., noble metal catalysts), γ-Fe2O3/mCN-900-20 exhibited high catalytic performance (TOF of 311.83 h-1, selectivity of 100%). During the catalytic hydrogenation of nitroaromatic compounds with reducible groups, e.g., alcoholic hydroxyl, halogen, and amino groups, an excellent selectivity close to 100% was achieved. Moreover, because the active sites of γ-Fe2O3 has magnetic performance, the catalyst can be easily recovered using a magnet, and reused at least four runs without an obvious activity decrease. Hence, the easily prepared, cost-effective and reusable γ-Fe2O3/mCN catalyst fabricated in this study demonstrates potential for applications in selective reduction of aromatic nitro compounds.
- Cui, Xueliang,Zhang, Qiaolan,Tian, Meng,Dong, Zhengping
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p. 10165 - 10173
(2017/09/18)
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- Insight into the mechanism of gold-catalyzed reduction of nitroarenes based on the substituent effect and: In situ IR
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A study is presented here on the mechanistic pathway of catalytic reduction of nitroarenes with diverse substituent groups in the presence of ultra-small gold nanoparticles and NaBH4. The kinetic data based on the substituent effect and the Hammett plot, together with analyses of intermediates, revealed that this reaction followed a direct route and that all of the reaction steps were rapid without accumulation of intermediates. In particular, in situ IR was found to be an effective method for the real-time monitoring of this model reduction in our catalytic system and confirmed the presence of a hydroxylamine intermediate. These results will provide a new insight into the mechanism of gold-catalyzed reduction of nitroarenes and offer a reference for future mechanism tests of heterogeneous nanocatalysis.
- Wang, Cui,Zou, Wei,Wang, Jiasheng,Ge, Yuzhen,Lu, Rongwen,Zhang, Shufen
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p. 3865 - 3871
(2017/07/12)
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- A process for the preparation of sulfanilic acid
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The invention discloses a preparation method for4-aminobenzenesulfonic acid. The4-aminobenzenesulfonic acid is prepared by a step of adding aniline into a reactor having an air condenser, and adding dropwise concentrated sulfuric acid having a concentration of 90% under stirring into the aniline, wherein the concentrated sulfuric acid is added for three times and next addition is performed 10 min later after each time of addition is finished; a step of heating with an oil bath, reacting at 180-190 DEG C for 1.5-2h, and adding dropwise sodium hydroxide having a concentration of 10% into the reaction liquid, wherein the reaction is completed when the reaction liquid is clear; a step of cooling to room temperature after the reaction is completed; and a step of putting reactants to a reactor containing ice water, precipitating grey 4-aminobenzenesulfonic acid crude product, subjecting the crude product to suction filtration, washing with water and recrystallizing with hot water to obtain the 4-aminobenzenesulfonic acid. The purity of the product can reach 99% and the yield of the product can reach 98%.
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Paragraph 0015-0016
(2017/03/08)
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- Polarizing film, image display device, and method for producing polarizing film
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The present invention provides a polarizing film having a high dichroic ratio. The polarizing film contains a disazo compound represented by the following general formula (1). In the general formula (1), Q1 represents a phenyl group having at least one —SO3M group; Q2 represents a naphthylene group having at least one —SO3M group; X represents an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a thioalkyl group having 1 to 4 carbon atoms, a halogeno group, or a polar group; subscript k denotes the number of substitutions of X and represents an integer of 0 to 5; and M represents a counter ion, where when k is an integer of 2 or more, Xs are the same or different.
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- A terminally protected dipeptide: from crystal structure and self-assembly, through co-assembly with carbon-based materials, to a ternary catalyst for reduction chemistry in water
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A terminally protected, hydrophobic dipeptide Boc-l-Cys(Me)-l-Leu-OMe (1) was synthesized and its 3D-structure was determined by single crystal X-ray diffraction analysis. This peptide is able to hierarchically self-assemble in a variety of superstructures, including hollow rods, ranging from the nano- to the macroscale, and organogels. In addition, 1 is able to drive fullerene (C60) or multiwalled carbon nanotubes (MWCNTs) in an organogel by co-assembling with them. A hybrid 1-C60-MWCNT organogel was prepared and converted (through a high vacuum-drying process) into a robust, high-volume, water insoluble, solid material where C60 is well dispersed over the entire superstructure. This ternary material was successfully tested as a catalyst for: (i) the reduction reaction of water-soluble azo compounds mediated by NaBH4 and UV-light with an overall performance remarkably better than that provided by C60 alone, and (ii) the NaBH4-mediated reduction of benzoic acid to benzyl alcohol. Our results suggest that the self-assembly properties of 1 might be related to the occurrence in its single crystal structure of a sixfold screw axis, a feature shared by most of the linear peptides known so far to give rise to nanotubes.
- Mazzier, Daniela,Carraro, Francesco,Crisma, Marco,Rancan, Marzio,Toniolo, Claudio,Moretto, Alessandro
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p. 238 - 245
(2015/12/30)
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- Degradation of sulfadiazine antibiotics by water falling film dielectric barrier discharge
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A new water falling film dielectric barrier discharge was applied to the degradation of sulfadiazine in the aqueous solution. The various parameters that affect the degradation of sulfadiazine and the proposed evolutionary process were investigated. The results indicated that the inner concentrations of 10 mg/L sulfadiazine can be all removed within 30 min. The optimum pH value was 9.10 and both strong acidic and alkaline solution conditions were not suitable for the degradation. The degradation of sulfadiazine can be enhanced by the addition of hydrogen radical scavengers, but be inhibited by adding hydroxyl radical scavengers. The water falling film dielectric barrier discharge was rather ineffective in mineralization, because of the intermediates were recalcitrant to be degraded. The existence of Fe2+ and CCl 4 in the liquid phase can promote the degradation and mineralization of sulfadiazine. It was found that the degradation of SDZ was enhanced by CCl4 was mainly because of the increase of OH due to the reaction of CCl4 with H that reduce the chances of their recombination with OH. Based on the 8 intermediate products identified by LC-MS, the proposed evolution of the degradation process was investigated.
- Rong, Shao-Peng,Sun, Ya-Bing,Zhao, Ze-Hua
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p. 187 - 192
(2014/02/14)
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- Factors affecting sonolytic degradation of sulfamethazine in water
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In this study, the major factors affecting sonolytic degradation of sulfamethazine (SMT), a typical pharmaceutically active compound, in water were evaluated. The factors tested included two operational parameters (i.e. initial SMT concentration and ultrasonic power), three dissolved gases (i.e. Ar, O 2 and N2), five most frequently found anions in water (NO3-,Cl-,SO42-,HCO3-andBr-), ferrous ion (Fe 2+), and four alcohols (methanol, ethanol, isopropyl alcohol, tert-butyl alcohol). Typically, the degradation rate was increased with the increasing initial SMT concentration and power. The degradation rate was accelerated in the presence of argon or oxygen, but inhibited by nitrogen. Effects of anions on the ultrasonic treatment were species-dependent. The SMT degradation rate was slightly inhibited by NO3-,Cl-,and,SO42- but significantly improved by HCO3-andBr-. The negative effects of alcohols acted as hydroxyl radicals scavengers with the following order: tert-butyl alcohol > isopropyl alcohol > ethanol > methanol. The synergetic effect of ferrous ion was mainly due to production of additional hydroxyl radicals (·OH) through Fenton chemistry. LC/MS/MS analysis indicated that the degradation of SMT by ultrasonic irradiation is mainly ascribed to ·OH oxidation. Of interest, although the SMT could be rapidly degraded by ultrasonic irradiation, the degradation products were rarely mineralized. For example, ~100% of 180 μM SMT was decomposed, but only 8.31% TOC was reduced, within 2 h at an irradiation frequency of 800 kHz and a power of 100 W. However, the products became much biodegradable (BOD 5/COD was increased from 0.04 to 0.45). Therefore, an aerobic biological treatment may be an appropriate post-treatment to further decompose the SMT degradation products.
- Gao, Yu-Qiong,Gao, Nai-Yun,Deng, Yang,Gu, Jin-Shan,Gu, Yu-Liang,Zhang, Dong
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p. 1401 - 1407
(2013/07/27)
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- Thermodynamics of phenylacetamides synthesis: Linear free energy relationship with the pK of amine
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The effective equilibrium constants K′C expressed through the total concentrations of the reagents for the synthesis of N-phenylacetyl-derivatives in aqueous medium from phenylacetic acid and various primary amino compounds have been determined with penicillin acylase as a catalyst. Broad specificity of penicillin acylase (EC 3.5.1.11) to amino components made possible to investigate the acylation of primary amines with different structures and physicochemical properties. Analysis of different components of the effective standard Gibbs energy change ΔGC o′ has revealed favorable thermodynamics for the synthesis of phenylacetamides from unionized substrates forms, however the ionization of reactants carboxy and amino groups in aqueous solutions pushes the equilibrium position to the hydrolysis especially in case of highly basic amines. A linear correlation between the standard Gibbs energy change for amide bond formation from the unionized reagents species and the basicity of amino group was observed: ΔGTo=-3.56pKamine+7.71(kJ/mol). The established linear free energy relationship (LFER) allows to predict the thermodynamic parameters for direct condensation of phenylacetic acid with any amine of known pK. Condensation of phenylacetic acid and amines with pK value within 1.5-8.5 was shown to be thermodynamically favorable in homogeneous aqueous solution. .
- Guranda, Dorel T.,Ushakov, Gennadij A.,Yolkin, Petr G.,Svedas, Vytas K.
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experimental part
p. 48 - 53
(2012/05/19)
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- Preparation and reactivity of a tetranuclear Fe(II) core in the metallothionein α-domain
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Metallothioneins (MTs) are small cysteine-rich proteins which exhibit high affinities for various metal ions and play roles in storage of essential metals and detoxification of toxic metals. Studies on the redox properties of MTs have been quite limited. Recently, we focused on the α-domain of MT (MTα) as a protein matrix and incorporated a tetranuclear metal cluster as a reductant. UV-visible, CD and MS data indicate the formation of the stable tetranuclear metal-cysteine cluster in the MTα matrix with Fe II4-MTα and CoII4-MTα species existing in water. Furthermore, the FeII4- MTα species was found to promote the reduction of met-myoglobin and azobenzene derivatives under mild conditions. Particularly, the stoichiometric reduction of methyl red with FeII4-MTα (1:1) was found to proceed with a conversion of 98% over a period of 6 h at 25 °C. This indicates that all of the four Fe(II) cores contribute to the reduction. In this paper, we describe the preparation and reactivity of the tetranuclear iron cluster in the protein matrix.
- Sano, Yohei,Onoda, Akira,Sakurai, Rie,Kitagishi, Hiroaki,Hayashi, Takashi
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experimental part
p. 702 - 708
(2012/02/16)
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- Optimization of the azobenzene scaffold for reductive cleavage by dithionite; development of an azobenzene cleavable linker for proteomic applications
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In this paper we conducted an extensive reactivity study to determine the key structural features that favour the dithionite-triggered reductive cleavage of the azo-arene group. Our stepwise investigation allowed identification of a highly reactive azo-arene structure 25 bearing a carboxylic acid, at the ortho position of the electron-poor arene and an ortho-Oalkyl-resorcinol as the electron-rich arene. Based on this 2(2′-alkoxy-4′-hydroxyphenylazo) benzoic acid (HAZA) scaffold, the orthogonally protected difunctional azo-arene cleavable linker 26 was designed and synthesized. Selective linker deprotection and derivatization was performed by introducing an alkyne reactive group and a biotin affinity tag. This optimized azo-arene cleavable linker led to a total cleavage in less than 10 s with only 1 mM dithionite. Similar results were obtained in biological media.
- Leriche, Geoffray,Budin, Ghyslain,Brino, Laurent,Wagner, Alain
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experimental part
p. 4360 - 4364
(2010/09/20)
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- Novel 2,3-disubstituted primary para-phenylenediamines and process for oxidation dyeing of keratin fibers
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Disclosed herein are para-phenylenediamine compounds of formula (I), and their salts and solvates: wherein R1 and R2 form, together with the carbon atoms to which they are attached, a 4-, 5-, 6- or 7-membered ring, wherein the ring comprises carbon atoms and, optionally, one or two atoms chosen from oxygen and nitrogen, the ring being optionally substituted, with the proviso that when the ring comprises two atoms chosen from oxygen and nitrogen, these two atoms are non-adjacent. Compositions comprising these compounds and processes of making them, as well as processes and kits for dyeing keratin fibers are also disclosed.
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Page/Page column 11-12
(2008/06/13)
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- One step hair coloring compositions using salts
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A hair coloring composition comprising the following two compositions which are mixed just prior to application to the hair: (a) a composition comprising a water-soluble peroxygen oxidizing agent; and (b) a composition comprising one or more oxidative hair coloring agents selected from the group consisting of an aromatic diamine, an amino phenol, a naphthol, a polyhydric phenol, a catechol and mixtures thereof; wherein the composition comprising one or more oxidative hair coloring agents further comprises al least one water soluble carbonate releasing salts; and optionally a water soluble ammonium salt, is described.
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- A study on the sulfonation of aromatic amines with sulfuric acid under microwave irradiation
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The sulfonation of aromatic amines with high yields, simple operations and short reaction time has been studied under microwave irradiation in solvent-free conditions.
- Li, Hui-Zhang,Xiao, Li-Wei,Li, Hong-Ya,Wang, Kai-Fang,Li, Xu
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p. 493 - 494
(2007/10/03)
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- Transition metal complexes as dye forming catalysts in hair coloring compositions
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A hair coloring composition comprising a first composition which comprises: (a) a dye forming transition metal salt or complex; which is first applied to the hair; and a second composition which comprises the following two compositions which are mixed just prior to application to the hair: (a) a composition comprising a water-soluble peroxygen oxidizing agent; and (b) a composition comprising one or more oxidative hair coloring agents selected from the group consisting of an aromatic diamine, an aminophenol, a polyhydric phenol a catechol and mixtures thereof.
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- Hair colouring and conditioning compositions
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A hair colouring and conditioning composition comprising: (a) a hair colouring agent; and (b) a hair conditioning agent; wherein the composition provides an Average Combing Index Value of greater than 1.2 as measured by the Combing Technical Test Method. The products can provide excellent hair colouring together with excellent conditioning, reduced hair damage, brittleness and dryness, and is convenient and easy to use.
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- Hair conditioning compositions and their use in hair colouring compositions
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The present invention relates to a hair care composition comprising a aminofunctional polysiloxane having a specified average effective particle size which provides improved durable conditioning particularly when utilised in conjunction with a hair colouring composition.
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- The quest for sulfoquinone imine intermediates in the reaction of sulfanilic acid derivatives with nucleophiles
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Data from kinetic and trapping studies suggest that the alkaline hydrolyses of sulfanilyl chloride and of the corresponding N-acetyl derivative follow different reaction pathways. While results for the latter compound are fully consistent with the occurrence of the common associative, SN2 mechanism, the former shows somewhat different features suggesting the incursion of a mechanism of the dissociative type involving a sulfoquinone imine species as a reaction intermediate. The alkaline hydrolyses of the corresponding sulfonyl fluorides and 2,4-dinitrophenyl esters, whose leaving groups are worse than Cl- as leaving groups, are all associative.
- Thea, Sergio,Vigo, Daniele,Cevasco, Giorgio
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p. 611 - 614
(2007/10/03)
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- HAIR COLORING COMPOSITIONS
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A hair coloring composition comprising: (a) from about 0.0003 moles (per 100 g of composition) to less than about 0.09 moles (per 100 g of composition) of an inorganic peroxygen oxidizing agent; and (b) an oxidative hair coloring agent; wherein the pH of each of (a) and (b) is in the range of from about 1 to about 6 and wherein the combined mixture of (a) and (b) has a pH in the range of from about 1 to about 6. The products can provide excellent hair coloring and in-use efficacy benefits including excellent initial color and good wash fastness in combination with reduced hair damage at low pH.
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- HAIR COLORING COMPOSITIONS
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A hair coloring composition comprising: (a) a preformed organic peroxyacid oxidising agent; and (b) an oxidative hair coloring agent; wherein the pH of each of components (a) and (b) is in the range of from about pH 1 to less than about pH 7 and wherein the pH of the composition is in the range of from about pH 1 to less than about pH 7. The products can provide excellent hair coloring and in-use efficacy benefits including excellent initial color and good wash fastness in combination with reduced hair damage at low pH.
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- Sulfonation of arylamines: Part 11 - Preparation and thermal decomposition of ring-substituted arylammonium hydrogen sulfates
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Eight ring-substituted arylammonium hydrogen sulfates (RSAHS) have been prepared by reacting corresponding arylamine with excess of conc. H2SO4. Their thermal decomposition has been investigated by TG and DSC techniques. The decomposition pathways have also been suggested.
- Singh,Kapoor,Singh
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p. 229 - 232
(2007/10/03)
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- Asymmetric dioxazine compounds and method for dyeing or printing fiber materials using the same
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An asymmetric dioxazine compound represented by the following formula (I) in the free acid form: STR1 wherein A1 and A2 independently of one another are each sulfo, halo, alkyl or alkoxy, X1 and X2 independently of one another are each hydrogen, halo, alkyl, alkoxy or phenoxy, R1 is hydrogen or unsubstituted or substituted alkyl, R2 and R3 independently of one another are each hydrogen, alkyl, alkoxy, halo or unsubstituted or substituted amino, Z is a fiber-reactive group, m and n independently of one another are each 0 or 1, provided that mn, and L is 1 or 2. This compound is suitable for dyeing and printing cellulose fiber, natural and synthetic polyamide fibers, polyurethane fiber, leather and the like and mixed yarns thereof, to obtain dyed or printed products of a color fast to light, wetness and chlorine with superior build-up and level dyeing properties.
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- Regeneration of dye-saturated quaternized cellulose by bisulfite- mediated borohydride reduction of dye azo groups: An improved process for decolorization of textile wastewaters
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Cellulosics modified to contain quaternary ammonium groups have a strong affinity for anionic dyes. Therefore, ion exchangers based on quaternized cellulose or ligno-cellulose can be used to remove textile dyes from wastewater. However, restoration of exchanger binding capacity is poor using conventional, low-cost regenerants. Experiments were conducted with two monoazo dyes, Orange II (Acid Orange 7) and Remazol Red F3B (Reactive Red 180), to determine whether reductive cleavage of dye azo bonds improves exchanger regenerability. Treatment with the redox couple KBH4/NaHSO3 fully restored the binding capacity of Orange II-saturated quaternized cellulose. KBH4/NaHSO3 treatment of quaternized cellulose saturated with Remazol Red F3B (hydrolyzed, unreactive form) restored 74% of the exchanger binding capacity, which increased to 95% with a subsequent wash with NaOH or NaClO4. High-performance liquid chromatography was used to confirm that KBH4/NaHSO3 reductively cleaved dye azo bonds. Bisulfite was found to form a stable adduct with Orange II but to not cleave the dye's azo bond. The efficiency of dye azo bond reduction was the same for dye in solution and exchanger-bound dye. These results indicate that reduction of monoazo dyes is an efficient method by which to regenerate the dye binding capacity of quaternized cellulosics used to decolorize textile wastewater. Cellulosics modified to contain quaternary ammonium groups have a strong affinity for anionic dyes. Therefore, ion exchangers based on quaternized cellulose or ligno-cellulose can be used to remove textile dyes from wastewater. However, restoration of exchanger binding capacity is poor using conventional, low-cost regenerants. Experiments were conducted with two monoazo dyes, Orange II (Acid Orange 7) and Remazol Red F3B (Reactive Red 180), to determine whether reductive cleavage of dye azo bonds improves exchanger regenerability. Treatment with the redox couple KBH4NaHSO3 fully restored the binding capacity of Orange II-saturated quaternized cellulose. KBH4NaHSO3 treatment of quaternized cellulose saturated with Remazol Red F3B (hydrolyzed, unreactive form) restored 74% of the exchanger binding capacity, which increased to 95% with a subsequent wash with NaOH or NaClO4. High-performance liquid chromatography was used to confirm that KBH4/NaHSO3 reductively cleaved dye azo bonds. Bisulfite was found to form a stable adduct with Orange II but to not cleave the dye's azo bond. The efficiency of dye azo bond reduction was the same for dye in solution and exchanger-bound dye. These results indicate that reduction of monoazo dyes is an efficient method by which to regenerate the dye binding capacity of quaternized cellulosics used to decolorize textile wastewater.
- Laszlo, Joseph A.
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p. 3647 - 3653
(2007/10/03)
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- Sulfonation of aromatic amines under conditions of microwave heating
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The possibility of intensifying solid-phase organic reactions by microwave heating is examined with sulfonation of aniline and α-naphthylamine as example. 1997 MAHK Hayka/Interperiodica Publishing.
- Brykov,Tselinskii,Astrat'ev
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p. 493 - 495
(2007/10/03)
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- Asymmetric dioxazine compounds and method for dyeing or printing fiber materials using the same
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An asymmetric dioxazine compound represented by the following formula (I) in the free acid form: STR1 wherein A1 and A2 independently of one another are each sulfo, halo, alkyl or alkoxy, W is an unsubstituted or substituted aliphatic or aromatic bridging group, X1 and X2 independently of one another are each hydrogen, halo, alkyl, alkoxy or phenoxy, R1 and R2 independently of one another are each hydrogen or unsubstituted or substituted alkyl, R3 and R4 independently of one another are each hydrogen, halo, alkyl, alkoxy or unsubstituted or substituted amino, Z is a fiber-reactive group, m and n independently of one another are each 0 or 1, provided that m≠n, and l is 1 or 2. This compound is suitable for dyeing and printing cellulose fiber, natural and synthetic polyamide fibers, polyrethane fiber, leather and the like and mixed yarns thereof, to obtain dyed or printed products of a color fast to light, wetness and chlorine with superior build-up and level dyeing properties.
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- Asymmetric dioxazine compounds having a triazinyl bridging group and a method of production and use thereof
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An asymmetric dioxazine compound of the following formula in the free acid form, STR1 wherein R is hydrogen, halogen, sulfo or alkoxy, R1, R2 and R3 are each hydrogen or alkyl, X1 and X2 are each hydrogen, halogen, alkyl, alkoxy or phenoxy, Y is alkylene, phenylene or naphthylene, Z is --SO2 CH=CH2, --SO2 CH2 CH2 OSO3 H or the like, V is hydrogen, alkyl, acyl or substituted triazinyl, and Q is halogen, alkoxy, amino or a group similar to that of STR2 provided that R is hydrogen, and Q is amino or a group similar to that of STR3 when V is substituted triazinyl, which is useful for dyeing or printing fiber materials to give dyed or printed products of a brilliant blue color superior in fastness properties, particularly those such as chlorine fastness with superior build-up property.
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- Mono- and bis-azo compounds containing 6-hydroxy-3-heterocyclic onium-pyridone-2-groupings coupled to diazo components containing diazine or triazine rings
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Reactive dyes of the formula STR1 where n is 1 or 2, X is a six-membered halogen-containing nitrogen heterocycle, L1, depending on n, is fluorine, chlorine, C1 -C4 -alkoxy, phenoxy, C1 -C4 -alkyl, substituted or unsubstituted phenyl or a bridge member which has one or two hydroxysulfonyl groups, D is the radical of a diazo component of the aniline or naphthalene series which has at least one hydroxysulfonyl group, L2 is hydrogen or substituted or unsubstituted C1 -C8 -alkyl, L3 is the cationic radical of an aromatic heterocycle which is linked to the pyridone ring via a nitrogen atom, and L4 is hydrogen or C1 -C4 -alkyl, with the proviso that the number of hydroxysulfonyl groups in the molecule exceeds that of the cationic groups by at least one, are useful for dyeing and printing hydroxyl- or nitrogen-containing substrates.
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- The Photochemistry of para-Substituted Phenylsulphamates - Photo-Fries Rearrangements
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The photolysis (254 nm) of a series of para-substituted phenylsulphamates, XC6H4NHSO3Na in degassed methanolic solutions has been examined.For 1a and 1b photo-Fries type rearrangements to sulphonic acids and photodegradation to anilines have been observed.The halogenosulphamates 1c-1e do not rearrange but degrade to anilines and are photosolvolysed to p-methoxyphenylsulphamic acid.No notable spectral changes took place during the irradiation of 1f over relatively long period.Substrate concentration studies, radical scavenging and sensitization and quenching experiments on 1b indicate that, as previously found for 1a, its photolysis involves an intramolecular radical mechanism with the participation of two triplet states.
- Lally, John M.,Spillane, William J.
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p. 803 - 807
(2007/10/02)
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- Photoisomerization and Photodegradation of Metanilic Acid
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The photolysis of metanilic acid (1) as the sodium metanilate, through quartz under helium at λ = 254 nm leading to the isomeric anilinesulphonic acids (2 and 3) and aniline (4) has been studied in water.The effects of pH and solvents on products, the acid-base catalysis of the photoreaction (pH-product profile) and the effects of substrate concentration, radical scavenging, triplet sensitization and quenching studies are reported. A mechanism involving a single triplet and a series of ?-complexes is proposed.
- Lally, John M.,Spillane, William J.
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p. 333 - 338
(2007/10/02)
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- Monoazo dyes, process for their preparation, and the use thereof
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The invention relates to monoazo dyes of the formula STR1 wherein K is the radical of a coupling component of the benzene, naphthalene or heterocyclic series, and R is hydrogen, halogen, carboxy, a C1 -C6 alkyl, C1 -C6 alkoxy, C2 -C6 alkanoylamino, C1 -C6 alkylsulfonylamino, C1 -C6 alkylsulfonyl, phenyl(C1 -C4)alkylsulfonyl or naphthyl(C1 -C4)alkylsulfonyl or benzoyl radical, which radicals may be further substituted, or is a STR2 group, wherein each of R1 and R2 independently of the other is hydrogen or a C1 -C6 alkyl, C5 -C7 cycloalkyl, phenyl or naphthyl radical, which radicals may be further substituted, and wherein X is hydrogen, halogen or a C1 -C6 alkyl, C1 -C6 alkoxy, C2 -C6 alkanoylamino or C1 -C6 alkylsulfonylamino radical, which radicals may be further substituted. These dyes give dyeings of good light- and wetfastness properties on polyamide material.
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- ISOMERIC TRANSFORMATIONS OF AMINOSULFONIC ACIDS OF THE BENZENE SERIES IN MIXTURES OF SULFURIC AND ACETIC ACIDS
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The isomerization rate of aminosulfonic acids in anhydrous binary mixtures of sulfuric and acetic acids is lower than in aqueous sulfuric acid solutions but higher than in 100percent sulfuric acid.This is explained by the differences in the structure and activity of the proton carriers during desulfonation.The rate of transformation of the labile isomers into the meta isomers increases with increase in the acidity of the medium, and this is due to the increase in the resulfonation rate of the protonating molecules of the amines formed during the desulfonation of the aminosulfonic acids.The effect of mercuric sulfate on the isomeric transformations of aminosulfonic acids is explained by the mercuration of the protonated molecules of the amines, which takes place at higher rates than their sulfonation and leads to the formation of the meta-mercury derivatives of the amines.The latter are than converted into the m-aminosulfonic acids by the action of concentrated sulfuric acid.
- Khelevin, R. N.
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p. 132 - 137
(2007/10/02)
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- Kinetics of Thermal Decomposition of Dianilinium Sulphate
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The thermal decomposition of arylammonium sulphate (dianilinium sulphate) has been investigated; sulphanilic acid is found to be the decomposition product.The mean value for the energy of activation (28.27 +/- 0.46 kcal mol-1) for the decomposition has been determined from isothermal TGA data , contracting area, contracting cube, and Jacobs-Kureishy equations.Thus, the decomposition of dianilinium sulphate seems to be controlled by a random nucleation process.The results suggest that the primary step (prior to sulphonation) in the decomposition of this salt is a proton-transfer process.
- Singh, Gurdip,Kapoor, Inder Pal Singh
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p. 2155 - 2158
(2007/10/02)
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