01495nas a2200217 4500008004100000022001400041245013500055210006900190260007300259300001400332490000700346520064600353653002600999653001701025653001901042653002501061653001401086100002601100700002201126856012901148 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. uhttp://library.ncl.res.in/content/magnesium-oxide-supported-nano-gold-highly-active-catalyst-solvent-free-oxidation-benzyl-003556nas a2200253 4500008004100000022001400041245010900055210006900164260007500233300001400308490000700322520266100329653001702990653001903007653001603026653002503042653002403067653001403091653001203105653001803117100002603135700002203161856011903183 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. uhttp://library.ncl.res.in/content/supported-nano-gold-catalysts-epoxidation-styrene-and-oxidation-benzyl-alcohol-001456nas a2200229 4500008004100000022001400041245012500055210006900180260010200249300001200351490000800363520056000371653000900931653001300940653004900953653001401002653000901016100002601025700002201051700002401073856012901097 2012 eng d a0974-362600aSolvent-free oxidation of aldehydes to acids by TBHP using environmental-friendly -exchanged Mg-Al hydrotalcite catalyst0 aSolventfree oxidation of aldehydes to acids by TBHP using enviro aC V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIAbINDIAN ACAD SCIENCEScJUL a835-8390 v1243 a

A number of hydrotalcite (Mg-Al, Mn-Al, Co-Al, Ni-Al, Mg-Fe, Mg-Cr and Cu-Al) catalysts, with or without MnO-exchange, were evaluated for their performance in the solvent-free oxidation of benzaldehyde to benzoic acid by tert-butyl hydroperoxide under reflux in the absence of any solvent. The MnO-exchanged Mg-Al-hydrotalcite (Mg/Al = 10) showed high activity in the oxidation of different aromatic and aliphatic aldehydes to their corresponding acids and also showed excellent reusability in the oxidation process which is environmental-friendly.

10aacid10aAldehyde10aMnO4-1-exchanged Mg-Al-hydrotalcite catalyst10aOxidation10aTBHP1 aChoudhary, Vasant, R.1 aDumbre, Deepa, K.1 aNarkhede, Vijay, S. uhttp://library.ncl.res.in/content/solvent-free-oxidation-aldehydes-acids-tbhp-using-environmental-friendly-exchanged-mg-al-0