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Benign Catalyst (benign + catalyst)
Selected AbstractsSynthesis of Rhodium Colloidal Nano-Coating Grafted Mesoporous Silica Composite and its Application as Efficient Environmentally Benign Catalyst for Heck-Type Reaction of Arylboronic AcidsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 5 2008Liang Li Abstract The synthesis and characterization of rhodium colloidal layer grafted mesoporous SBA-15 material, designated as SBA-Rh, are presented. In the preparation of this new catalyst, SBA-15 mesoporous material was used as support without any pretreatment. The SiH functional groups were introduced onto the surface which resulted in highly dispersed metal colloid layer both on the outer and inner surface of the supporting material. The material was investigated for Heck-type coupling reactions of alkenes with ayboronic in organic/water solvent. The ultrahigh specific area, large pore opening, and highly dispersed catalyst species in SBA-Rh material created one of the most active heterogeneous catalysts for such reactions. Rhodium element was not detected in the final mixture by ICP after reaction. The catalyst species showed very high stability against leaching from the matrix and can be recycled for repeated use. [source] BiOClO4×xH2O and Bi(OTf)3 as Efficient and Environmentally Benign Catalysts for Synthesis of Bis(indolyl)methanes in Solution and under Ultrasound Irradiation.CHEMINFORM, Issue 18 2007Iraj Mohammadpoor-Baltork Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Lipase-Catalyzed Synthesis and Properties of Poly[(12-hydroxydodecanoate)- co -(12-hydroxystearate)] Directed towards Novel Green and Sustainable ElastomersMACROMOLECULAR BIOSCIENCE, Issue 1 2008Hiroki Ebata Abstract Novel green and sustainable elastomers having both good biodegradability and chemical recyclability properties were designed and synthesized using potentially biobased materials and lipase as an environmentally benign catalyst. High molecular weight poly[(12-hydroxydodecanoate)- co -(12-hydroxystearate)] [poly(12HD- co -12HS)] samples with varying monomer ratios were prepared by the polycondensation of 12-hydroxydodecanoic acid and methyl 12-hydroxystearate using immobilized lipase from Candida antarctica (IM-CA) in toluene in the presence of molecular sieves 4A at 90,°C. Although poly(12HD) is a highly crystalline polyester having a melting temperature (Tm) of 87.6,°C and crystalline temperature (Tc) of 64,°C, by the copolymerization of 12HD with 12HS, both the Tm and Tc of the copolymer decreased with increasing 12HS contents, and poly(12HD- co -12HS) containing more than 60 mol-% 12HS was a viscous liquid at room temperature. At the same time, the Young's modulus and hardness also decreased with increasing 12HS content, and poly(12HD- co -36 mol-% 12HS) exhibited an elastic behavior, having a hardness of 70 A using a durometer A. In addition, it showed an excellent biodegradability by activated sludge and chemical recyclability by lipase. [source] Phase-Transfer-Catalyzed Intramolecular Cyclization of ortho -Alkynyl Phenyl Ether Derivatives for Synthesis of 2,3-Disubstituted Benzo[b]furansADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010Jie Hu Abstract A variety of substituted benzo[b]furans are readily prepared in good to excellent yields under the mild reaction conditions from o -(1-alkynylphenoxy)-1-phenylethanone under phase-transfer catalysis (PTC). This methodology accommodates simple experimental operations, inexpensive and environmentally benign catalysts, metal catalyst-free conditions, facile reagents and the possibility to conduct large-scale preparations. The development of carbon-carbon bond formation processes via an overall structural isomerization represents the most atom-economical approach. [source] | ||||||||||