88-45-9Relevant academic research and scientific papers
General Strategy to Fabricate Metal-Incorporated Pyrolysis-Free Covalent Organic Framework for Efficient Oxygen Evolution Reaction
Gao, Zhi,Gong, Le Le,He, Xiang Qing,Luo, Feng,Su, Xue Min,Xiao, Long Hui
, (2020/03/30)
Because of the permission of the manipulations of modular construction on the atomic level, covalent organic frameworks (COFs) have attracted extensive attention in the electrocatalytic field. Owing to the lack of metal sites in pristine COFs constructed only by metal-free organic building units, it generally exhibits extremely low electrocatalytic activity. Thereby, linking metal sites on the backbone of pyrolysis-free COFs but not loading them on the surface to enhance the electrocatalytic activity is highly desirable but still remains a huge challenge. To this end, herein, we report an efficient and general cation-exchange strategy to synthesize Ni/Fe metal-ion-incorporated COFs (NixFe1-x?COF-SO3) for the oxygen evolution reaction (OER) based on the fundamental structure design of COFs. Impressively, the turnover frequency (TOF) value in Ni0.5Fe0.5?COF-SO3 reaches 0.14 s-1 at the overpotential of 300 mV, which outperforms most recently reported OER electrocatalysts, indicative of ultrahigh metal-atom utilization efficiency.
Flexible and robust bimetallic covalent organic frameworks for the reversible switching of electrocatalytic oxygen evolution activity
Gao, Zhi,He, Xiangqing,Huang, Xinhui,Huang, Yuxing,Luo, Feng,Su, Xuemin,Xiao, Longhui,Yu, Yi,Yu, Zhiwu
, p. 5907 - 5912 (2020/04/08)
Flexible and robust catalysts present a highly intriguing issue owing to their unique dynamic and reversible switching nature, which can provide a solution to maximize the atom utilization efficiency. Herein, a convenient and efficient cation-exchange strategy was developed to prepare flexible and robust Co/V-incorporated bimetallic COF electrocatalysts (namely, CoxV1-x?COF-SO3) for the oxygen evolution reaction (OER). As expected, in a 1.0 M KOH electrolyte, the optimized bimetallic Co0.5V0.5?COF-SO3 showed high turnover frequency (TOF) (0.098 s-1) at the overpotential of 300 mV, which was superior to that of most of the recently reported excellent Co-based OER electrocatalysts, exhibiting high atom utilization efficiency. Most importantly, the flexible nature of Co0.5V0.5?COF-SO3 was also observed. After treatment with hydrochloric acid, the reformation of the catalysis-inert phase of COF-SO3H was observed. This unique transformation from the catalysis-active phase of Co0.5V0.5?COF-SO3 to the catalysis-inert phase of COF-SO3H can be repeated, suggesting reversible switching of OER activity, which are almost impossible to achieve in conventional catalysts. This work provides a new concept for the fundamental design of catalysts with reversible switching properties to improve the atom utilization efficiency and simplify the procedures of catalyst regeneration.
Ultralow-content palladium dispersed in covalent organic framework for highly efficient and selective semihydrogenation of alkynes
Li, Jian Hong,Yu, Zhi Wu,Gao, Zhi,Li, Jian Qiang,Tao, Yuan,Xiao, Yu Xin,Yin, Wen Hui,Fan, Ya Ling,Jiang, Chao,Sun, Li Jun,Luo, Feng
supporting information, p. 10829 - 10836 (2019/08/22)
Developing noble-metal-based catalysts with ultralow loading to achieve excellent performance for selective hydrogenation of alkynes under mild reaction conditions is highly desirable but still faces huge challenges. To this end, a SO3H-anchored covalent organic framework (COF-SO3H) as the support was deliberately designed, and then ultralow-content Pd (0.38 wt %) was loaded by a wet-chemistry immersion dispersion method. The resulting Pd0.38/COF-SO3H composite exhibits outstanding performance for the selective hydrogenation of phenylacetylene with 97.06% conversion and 93.15% selectivity to styrene under mild reaction conditions (1 bar of H2, 25 °C). Noticeably, the turnover frequency value reaches as high as 3888 h-1, which outperforms most of reported catalysts for such use. Moreover, such a catalyst also exhibits excellent activity for a series of other alkynes and high stability without obvious loss of catalytic performance after five consecutive cycles.
CuFe2O4@PDA magnetic nanomaterials with a core-shell structure: Synthesis and catalytic application in the degradation of methylene blue in water
Ma, Su-Dai,Feng, Jie,Qin, Wen-Jie,Ju, Yu-Yun,Chen, Xing-Guo
, p. 53514 - 53523 (2015/06/30)
In this paper, core-shell polydopamine (PDA)-encapsulated CuFe2O4 (CuFe2O4@PDA) magnetic nanoparticles (MNPs) were synthesized through in situ self-polymerization for the first time. The size of the core-shell product can be controlled by tuning the dopamine monomer concentration. The formation of a PDA layer effectively enhanced the catalytic performance and provided a large specific surface area which offered more active sites for the effective interaction. The as-synthesized CuFe2O4@PDA MNPs were characterized and their catalytic activity was evaluated using the degradation of methylene blue (MB) in the presence of H2O2 as a model reaction. The experimental results showed that MB could be degraded efficiently using CuFe2O4@PDA MNPs as a catalyst. Under the optimized conditions, the degradation efficiency of MB was above 97%. Furthermore, a possible reaction mechanism was discussed. Finally, the catalyst was used for effective degradation of MB in a Yellow River water sample, which indicates its potential for practical applications in water pollutant removal and environmental remediation.
Development of an efficient ruthenium catalyzed synthetic process and mechanism for the facile conversion of benzothiazoles to orthanilic acids
Jagadeesh,Karthikeyan,Nithya,Sandhya, Y. Sree,Reddy, S. Sudhaker,Reddy, P. Pradeep Kumar,Kumar, M. Vinod,Charan, K.T. Prabhu,Narender,Bhagat
experimental part, p. 99 - 107 (2010/12/18)
Ruthenium-Schiff base complex catalyzed efficient protocol has been developed for the synthesis of orthanilic acids from benzothiazoles in good to excellent yields using N-haloamines. Hexa-coordinated ruthenium complex with Schiff base and triphenylphosphine ligands has been prepared and its catalytic function was invented for the synthesis of orthanilic acids. The synthetic process utilizes our efficient method for the selective and preferential oxidation of thiazole ring of benzothiazoles using N-haloamines without effecting phenyl ring. The detailed catalytic, mechanistic and kinetic investigations have been made for the synthetic reactions. Solvent isotope studies have been made in H2O-D2O and the reactions were carried out at different temperatures. Under the identical set of conditions, the kinetics of catalyzed reactions has been compared with uncatalyzed reactions and found that the catalyzed reactions are 9-11 folds faster. The catalytic constants (KC) have been calculated for each N-haloamine at different temperatures and the values of activation parameters with respect to the catalyst have been evaluated. Spectroscopic evidence for the formation of 1:1 complex between N-haloamine and ruthenium has been obtained. The observed results have been explained by a plausible mechanism and the related rate law has been deduced.
Process for dyeing keratinous fibers with aminoindoles and oxidation dye precursors at basic Ph's and dyeing agents
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, (2008/06/13)
The invention relates to a process for dyeing keratinous fibres, which consists in applying to these fibres a composition containing, in a suitable medium for dyeing, at least one coupler of formula: STR1 where R1 denotes hydrogen or alkyl, R2 and R3 denote hydrogen, alkyl, COOR' where R' is alkyl or hydrogen, at least one of the groups R2 and R3 denoting hydrogen, R4 denotes hydrogen, alkyl, hydroxyalkyl, polyhydroxyalkyl or aminoalkyl, Z1 and Z2 denote hydrogen, alkyl, hydroxyl, halogen, alkoxy, at least one of the groups Z1 and Z2 is other than hydrogen at least one oxidation dye precursor, at least one oxidizing agent, the pH of the composition applied to the fibres being higher than 7.
Methods for dyeing keratinous fibers with compositions which contain aminoindole couplers, oxidation dye precursors, and oxidizing agents at acid pHs
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, (2008/06/13)
A method for dyeing keratin fibers, wherein a composition is applied to said fibers which contains, in a suitable dyeing medium, at least one coupler having formula (I) STR1 wherein R1 is hydrogen or alkyl; R2 and R3 are hydrogen, alkyl, COOR', where R' is alkyl or hydrogen; R4 is hydrogen, hydroxyalkyl, alkyl, polyhydroxyalkyl or acetyl or aminoalkyl wherein the amine may be mono- or disubstituted by alkyl; Z1 and Z2 are hydrogen, alkyl, hydroxy, halogen, alkoxy or a salt thereof; at least one precursor of an oxidation hair dye; and at least one oxidizing agent, the pH of the composition applied to the fibers being less than 7.
3-substituted para-aminophenols
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, (2008/06/13)
The invention concerns the use of a 3-substituted para-aminophenol as an oxidation dye precursor for dyeing keratinous fibres, in particular human hair. The 3-substituted para-aminophenol has formula: STR1 where R1 represents alkyl, alkenyl, mono- or polyhydroxyalkyl, nitrile, cyanoalkyl, halogenoalkyl, aminoalkyl or alkoxyalkyl and R2 represents hydrogen, alkyl or mono- or polyhydroxyalkyl, provided that when R2 is hydrogen R1 is not methyl or trifluoromethyl, and to addition salts thereof with an acid. The invention also concerns dye compositions containing compound (I). The invention further concerns novel 3-substituted para-aminophenols.
Triazinyl reactive dyestuffs in which triazinyl group is further substituted with a beta-chloroethylsulfonyl- or vinylsulfonylbutyrylamino moiety
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, (2008/06/13)
Reactive dyes of the formula STR1 in which D is the radical of an organic dye of the monoazo, polyazo, metal complex azo, anthraquinone, phthalocyanine, formazan, azomethine, dioxazine, phenazine, stilbene, triphenylmethane, xanthene, thioxanthrone, nitroaryl, naphthoquinone, pyrenequinone or perylenetetracarbimide series, R is hydrogen or substituted or unsubstituted C1-4 -alkyl, X is a substituent which is detachable as an anion, B is a radical of the formula STR2 R1 and R2, independently of each other, are hydrogen or substituted or unsubstituted C1-4 -alkyl or phenyl, A is a substituted or unsubstituted aliphatic or aromatic bridge member, Y is a --CO--Z or --SO2 --Z radical, Z is an aliphatic, aromatic or heterocyclic reactive radical, and n is 1 or 2, are suitable for dyeing or printing cellulose-containing and nitrogen-containing materials and in high dyeing yield produce dyeings and prints having good fastness properties.
