01496nas a2200217 4500008004100000022001400041245013500055210006900190260007300259300001400332490000700346520064600353653002600999653001701025653001901042653002501061653001401086100002601100700002201126856013001148 2009 eng d a1566-736700aMagnesium oxide supported nano-gold: a highly active catalyst for solvent-free oxidation of benzyl alcohol to benzaldehyde by TBHP0 aMagnesium oxide supported nanogold a highly active catalyst for  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJUL a1738-17420 v103 a

Nano-size gold particles deposited on MgO by the homogeneous deposition- precipitation showed very high catalytic activity with nearly 100% conversion of benzyl alcohol in a short reaction period (0.5 h) and more over showed excellent reusability in the process. Influence of the catalyst support (MgO, CaO, BaO, SrO, Al(2)O(3), Ga(2)O(3) and In(2)O(3)), method of gold deposition, Au loading and catalyst calcination temperature and also that of the reaction conditions (viz. reaction time and temperature) on the benzyl alcohol to benzaldehyde oxidation have been thoroughly investigated. (C) 2009 Elsevier B.V. All rights reserved.

10aAlkaline earth oxides10aBenzaldehyde10aBenzyl alcohol10aGr.IIIa metal oxides10aOxidation1 aChoudhary, Vasant, R.1 aDumbre, Deepa, K. uhttps://library.ncl.res.in/content/magnesium-oxide-supported-nano-gold-highly-active-catalyst-solvent-free-oxidation-benzyl-003557nas a2200253 4500008004100000022001400041245010900055210006900164260007500233300001400308490000700322520266100329653001702990653001903007653001603026653002503042653002403067653001403091653001203105653001803117100002603135700002203161856012003183 2009 eng d a1022-552800aSupported nano-gold catalysts for epoxidation of styrene and oxidation of benzyl alcohol to benzaldehyde0 aSupported nanogold catalysts for epoxidation of styrene and oxid a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGER/PLENUM PUBLISHERScNOV a1677-16870 v523 a

Nano-gold particles supported on different alkaline earth oxides (viz. MgO, CaO, BaO and SrO), Gr. IIIa metal oxides (viz. Al(2)O(3), Ga(2)O(3), In(2)O(3) and Tl(2)O(3)), transition metal oxides (viz. TiO(2), Cr(2)O(3), MnO(2), Fe(2)O(3), CoO(x), NiO, CuO, ZnO, Y(2)O(3) and ZrO(2)), rare earth metal oxides (viz. La(2)O(3), Ce(2)O(3), Nd(2)O(3), Sm(2)O(3), Eu(2)O(3), Tb(2)O(3), Er(2)O(3) and Yb(2)O(3)) and U(3)O(8) [all prepared by depositing gold on corresponding metal oxide support by deposition precipitation (DP) and/or homogeneous deposition precipitation (HDP) method] were evaluated for their catalytic performance in the liquid phase epoxidation of styrene by tert-butyl hydroperoxide (TBHP) to styrene oxide and also in the solvent-free benzyl alcohol-to-benzaldehyde oxidation (by molecular oxygen or TBHP) reactions. For the epoxidation, the catalytic performance (styrene oxide yield) of the most promising nano-gold catalysts prepared by the HDP method was in the following order: Au/MgO > Au/Tl(2)O(3) > Au/Yb(2)O(3) > Au/Tb(2)O(3) > Au/CaO (or TiO(2)). However, for the oxidation of benzyl alcohol to benzaldehyde by molecular oxygen, the order of choice for the most promising catalysts (based on benzaldehyde yield) was Au/U(3)O(8) > Au/Al(2)O(3) > Au/ZrO(2) > Au/MgO. Whereas, when TBHP was used as an oxidizing agent for the benzyl alcohol oxidation, the order of choice for the most promising catalysts was Au/U(3)O(8) > Au/MgO > Au/TiO(2) > Au/ZrO(2) > Au/Al(2)O(3). The catalytic performance of a particular supported nano-gold catalyst was thus found to depend on the reaction catalysed by them. Moreover, it is strongly influenced by a number of catalyst parameters, such as the metal oxide support, the method of gold depositon on the support, the gold loading and also on the catalyst calcination temperature. Nano-gold particles-support interactions seem to play an important role in controlling the deposition of gold ( amount of gold deposited and size and morphology of gold particles), formation of different surface gold species (Au(0), Au(1+) and Au(3+)) and electronic properties of gold particles and, consequently, control the catalytic performance (both the activity and selectivity) of the supported nano-gold catalysts in the reactions. The nano-gold catalysts prepared by the HDP method showed much better catalytic performance than those prepared by the DP, coprecipitation or impregnation method; in general, the HDP method provided supported gold catalysts with much higher gold loading and/or smaller size gold particles than that achieved by the DP and other methods.

10aBenzaldehyde10aBenzyl alcohol10aepoxidation10aMetal oxide supports10aNano-gold catalysts10aOxidation10astyrene10aStyrene oxide1 aChoudhary, Vasant, R.1 aDumbre, Deepa, K. uhttps://library.ncl.res.in/content/supported-nano-gold-catalysts-epoxidation-styrene-and-oxidation-benzyl-alcohol-001942nas a2200229 4500008004100000022001400041245013900055210006900194260007300263300001200336490000800348520105400356653002101410653001701431653001901448653001401467653002201481653002901503100002601532700002201558856013201580 2010 eng d a0926-860X00aSolvent-free selective oxidation of benzyl alcohol to benzaldehyde by tert-butyl hydroperoxide over U3O8-supported nano-gold catalysts0 aSolventfree selective oxidation of benzyl alcohol to benzaldehyd aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAR a252-2570 v3753 a

Liquid-phase oxidation of benzyl alcohol to benzaldehyde by tertiary butyl hydroperoxide over different uranium oxide supported nano-gold catalysts in the absence of a solvent has been thoroughly investigated. The influences of catalyst parameters [viz, method of gold deposition (impregnation, co-precipitation, deposition-precipitation and homogeneous deposition-precipitation), gold loading (08 wt%) and catalyst calcination temperature (100-900 degrees C)] on the catalyst performance have been investigated. The influence of reaction conditions [viz, reaction time (0-2 h) and temperature (25-94 degrees C)] on the process performance has also been studied. The Au/U3O8 catalyst prepared by the homogeneous deposition-precipitation and calcined at 400 degrees C showed very high activity (100% benzyl alcohol conversion with >85% selectivity for benzaldehyde) in the process for a short reaction period (0.5 h) at 94 degrees C. The catalyst also showed excellent reusability in the process. (C) 2010 Elsevier B.V. All rights reserved.

10aAu/U3O8 catalyst10aBenzaldehyde10aBenzyl alcohol10aNano-gold10aPartial oxidation10atert-Butyl hydroperoxide1 aChoudhary, Vasant, R.1 aDumbre, Deepa, K. uhttps://library.ncl.res.in/content/solvent-free-selective-oxidation-benzyl-alcohol-benzaldehyde-tert-butyl-hydroperoxide-over-0