01095nas a2200169 4500008004100000022001400041245013400055210006900189260011000258300001600368490000600384520034400390100002800734700002000762700002100782856012200803 2013 eng d a2046-206900aEfficient, direct synthesis of dimethyl carbonate from CO2 using a solid, calcined zirconium phenylphosphonate phosphite catalyst0 aEfficient direct synthesis of dimethyl carbonate from CO2 using  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcOCT a23993-239960 v33 a

Direct synthesis of dimethyl carbonate (DMC) from CO2 and methanol with 100 mol% selectivity using a solid, reusable, hydrophobic, calcined zirconium phenylphosphonate phosphite catalyst is reported for the first time. DMC yield as high as 26 mmol g(-1) catalyst correlated with the concentration of acid and base sites is obtained.

1 aUnnikrishnan, Pulikkeel1 aVarhadi, Poonam1 aSrinivas, Darbha uhttps://library.ncl.res.in/content/efficient-direct-synthesis-dimethyl-carbonate-co2-using-solid-calcined-zirconium-002079nas a2200229 4500008004100000022001400041245013900055210006900194260007300263300001200336490000800348520116000356653001901516653002001535653005001555653002501605653001801630653003601648100002001684700002101704856012401725 2014 eng d a0926-860X00aEffects of method of preparation on catalytic activity of Co-Zn double-metal cyanide catalysts for copolymerization of CO2 and epoxide0 aEffects of method of preparation on catalytic activity of CoZn d aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJUL a300-3080 v4823 a

Co-Zn double-metal cyanide (DMC) complexes are well-known catalysts for ring-opening polymerization of epoxides and co-polymerization of CO2 and epoxides. This work provides an insight on structure-activity relationship of DMC for poly(cyclohexene carbonate) synthesis. Seven samples of DMC were prepared by different methods and mode of reagent addition. Highly active catalyst could be synthesized even without using a co-complexing agent. CO2 adsorption studies revealed that higher the guest-host interaction higher would be the catalytic activity. High density and strength of Lewis acid sites, moderate crystallinity, low crystal symmetry (rhombohedral/monoclinic), Cl- ions and coordinated tert.-butanol (complexing agent) control the catalytic activity for polycarbonates. Chloride in the structure avoided induction period by increasing acidity of the catalyst and thereby, improving the guest-host interactions. Polycarbonates with CO2 incorporation as high as 86 mol%, average molecular weight of 20900 and polydispersity index of 1.8 were prepared at complete conversion of cyclohexene oxide. (C) 2014 Elsevier B.V. All rights reserved.

10aCarbon dioxide10aCO2 utilization10aCopolymerization of CO2 and cyclohexene oxide10aDouble-metal cyanide10aPolycarbonate10aStructure-activity relationship1 aSebastian, Joby1 aSrinivas, Darbha uhttps://library.ncl.res.in/content/effects-method-preparation-catalytic-activity-co-zn-double-metal-cyanide-catalysts-002468nas a2200157 4500008004100000022001400041245013200055210006900187260011000256300001600366490000600382520175200388100002102140700002102161856012802182 2015 eng d a2046-206900aEffect of alkali and alkaline earth metal ions on benzyl alcohol oxidation activity of titanate nanotube-supported Au catalysts0 aEffect of alkali and alkaline earth metal ions on benzyl alcohol aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcMAY a47740-477480 v53 a

Sodium titanate nanotubes (NaTNTs) were prepared by alkali treatment of anatase titania. They were then ion-exchanged with alkali and alkaline earth metal ions to get ATNTs (A = Li+, K+, Cs+, Mg2+, Ca2+, Sr2+ and Ba2+). Gold (1-5 wt%) was supported on these nanotubes by a deposition-precipitation method and investigated as a catalyst for the selective oxidation of benzyl alcohol with air/molecular oxygen (1 atm) under solvent-and alkali-free conditions. Detailed characterization by X-ray powder diffraction, high resolution transmission electron microscopy, N-2-physisorption, diffuse reflectance UV-visible spectroscopy, X-ray photoelectron spectroscopy and CO2-temperature-programmed desorption techniques revealed that the basicity of the catalyst influences the uptake, mean particle size, electronic properties and oxidation activity of the supported gold. Benzaldehyde formed with a selectivity of about 99%. The catalytic activity (turnover frequency) was found to have a direct relationship with the basicity and an inverse relationship with the Au particle size. Among the catalysts investigated, Au/BaTNTs, having higher basicity, smaller Au particles and higher metal dispersion, showed enhanced catalytic activity than the other Au/ATNT catalysts. Pd addition to Au leading to Au-Pd/BaTNTs increased the activity (TOF) but lowered the selectivity for benzaldehyde (80 wt%). Titanate nanotubes donate electron density to Au particles, yielding electron rich Au ions, which are responsible for activating molecular oxygen and oxidizing benzyl alcohol. Au/BaTNTs, having higher basicity and lower size Au nanoparticles than the other Au/ATNT, activates molecular oxygen more easily and thereby enhances the catalytic activity.

1 aNepak, Devadutta1 aSrinivas, Darbha uhttps://library.ncl.res.in/content/effect-alkali-and-alkaline-earth-metal-ions-benzyl-alcohol-oxidation-activity-titanate-001613nas a2200205 4500008004100000245016200041210006900203260000800272300001200280490000700292520082600299100001901125700002301144700002001167700002801187700002601215700002101241700002101262856012401283 2016 eng d00aEffects of thermal treatment of ZnO-ZnCr2O4 catalyst on the particle size and product selectivity in dehydrocyclization of crude glycerol and ethylenediamine0 aEffects of thermal treatment of ZnOZnCr2O4 catalyst on the parti cSEP a602-6090 v573 aThe ZnO-ZnCr2O4 (Zn-Cr-O) sample obtained by decomposition of Zn-Cr hydrotalcite precursor was subjected to the thermal treatment at different temperatures and the physico-chemical properties of the Zn-Cr-O system were compared with its catalytic behavior in dehydrocyclization of crude glycerol and ethylenediamine (EDA). Upon high temperature treatment of Zn-Cr-O the Cr6+ ions underwent autoreduction to form stable Cr3+ species and the particle size of both ZnO and ZnCr2O4 increased dramatically. Thermal effect did not influence the intermolecular cyclisation of EDA to form pyrazine. By contrast, an inversely proportional dependence was found between the rate of formation of 2-methylpyrazine and the particle size of Zn-Cr-O whereas the rate of 2-pyrazinylmethanol was directly proportional to the particle size.1 aSarkari, Reema1 aKrishna, Vankudoth1 aSudhakar, Medak1 aRao, Tumula, Venkateshw1 aPadmasri, Aytam, Hari1 aSrinivas, Darbha1 aVenugopal, Akula uhttps://library.ncl.res.in/content/effects-thermal-treatment-zno-zncr2o4-catalyst-particle-size-and-product-selectivity