01695nas a2200289 4500008004100000022001400041245009900055210006900154260007300223300001400296490000700310520072300317653000601040653001701046653001801063653001401081653002201095653001901117653002501136100002101161700001701182700002001199700002201219700001901241700002501260856012001285 2009 eng d a1566-736700aMoO3/SiO2: an efficient and selective catalyst for the synthesis 1,3-dioxolane and 1,3-dioxane0 aMoO3SiO2 an efficient and selective catalyst for the synthesis 1 aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAY a1404-14090 v103 a

A series of MoO3/SiO2 catalysts with varying amounts of MoO3 has been synthesized and the catalytic activities of these were compared with the known solid acid catalysts in the synthesis of 1,3-dioxolane. MoO3/SiO2 catalyst showed a better activity and selectivity in 1,3-dioxolane synthesis compared to the other catalysts. MoO3/SiO2 catalyst system was further successfully applied for the synthesis of 1,3-dioxanes in the Prins cyclization of olefins and formaldehyde. The proposed catalyst was thermally stable and could be recovered and reused at least in four consecutive cycles with no significant loss in the substrates conversions and products selectivities. (C) 2009 Elsevier B.V. All rights reserved.

10a110a3-Dioxolanes10aCycloaddition10aMoO3/SiO210aPrins cyclization10aSol-gel method10asolid acid catalysts1 aAmrute, Amol, P.1 aSahoo, Suman1 aBordoloi, Ankur1 aHwang, Young, Kyu1 aHwang, Jin-Soo1 aHalligudi, Shiva, B. uhttp://library.ncl.res.in/content/moo3sio2-efficient-and-selective-catalyst-synthesis-13-dioxolane-and-13-dioxane-002010nas a2200229 4500008004100000022001400041245012500055210006900180260007300249300001200322490000800334520115300342653001601495653002201511653001401533653002201547653002501569100002101594700002301615700001701638856012501655 2009 eng d a0926-860X00aSelective hydroxyalkylation of phenol to bisphenol F over dodecatungstophosphoric acid (DTP) impregnated on fumed silica0 aSelective hydroxyalkylation of phenol to bisphenol F over dodeca aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcFEB a176-1820 v3543 a

The catalyst activity of various solid acids, such as fumed Silica (SiO(2)) dodecatungstophosphoric acid (DTP), DTP impregnated on SiO(2), amberlyst-15 and montmorillonite KSF/0, was studied for the hydroxyalkylation of phenol to bisphenol F. A well-dispersed DTP on SiO2 catalyst was prepared by the wet impregnation method. The effect of DTP loading on SiO(2) was also compared with bulk DTP and other solid acid catalysts. 20% DTP/SiO(2) catalyst gave the highest products yield of 34.2% and selectivity of 90.1% to bisphenol F, at 353 K and with a phenol-to-formaldehyde mole ratio of 5:1. Ammonia TPD studies of various catalysts showed that an appropriate combination of both strong and weak acid sites of DTP/SiO(2) Was mainly responsible, rather than only the stronger acidity of bulk DTP, for its highest catalytic activity and selectivity. The effect of various reaction parameters like mole ratio, catalyst concentration, temperature and reaction time on product yield and bisphenol F selectivity was also investigated. The catalyst recycle was established by catalyst activity testing. (C) 2008 Elsevier B.V. All rights reserved.

10aBisphenol F10aHydroxyalkylation10aNH(3)-TPD10aReaction pathways10asolid acid catalysts1 aGarade, Ajit, C.1 aKshirsagar, V., S.1 aRode, C., V. uhttp://library.ncl.res.in/content/selective-hydroxyalkylation-phenol-bisphenol-f-over-dodecatungstophosphoric-acid-dtp-002109nas a2200229 4500008004100000022001400041245012000055210006900175260007500244300001200319490000700331520122900338653001901567653002301586653002201609653003301631653002501664100001701689700002101706700002401727856012801751 2009 eng d a1571-101300aSolid acid catalysts: modification of acid sites and effect on activity and selectivity tuning in various reactions0 aSolid acid catalysts modification of acid sites and effect on ac a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGER/PLENUM PUBLISHERScSEP a205-2200 v133 a

The effects of acidity and variation in concentration of acid sites of dodecatungstophosphoric acid (DTP), supported DTP and montmorillonite-K catalysts were studied for various organic reactions such as the hydroxyalkylation of phenols to bisphenols, intramolecular rearrangement of benzyl phenyl ether (BPE) to 2-benzyl phenol (2-BP) and selective cleavage of tert-butyldimethylsilyl (TBDMS) ether into the corresponding alcohol. Both dodecatungstophosphoric acid (DTP) impregnated on silica (SiO(2)) and montmorillonite catalysts showed the highest catalyst activity with 90-95% selectivity to bisphenol for the hydroxyalkylation of phenols to give bisphenol. Temperature Programmed Desorption (TPD) of ammonia and activity results of various catalysts showed that an appropriate combination of both strong and weak acidic sites in the catalyst was highly desirable for high bisphenol selectivity. A 10% DTP/SiO(2) catalyst was found to be highly selective for the cleavage of TBDMS ether into the corresponding alcohol at room temperature giving a high TON of 9.5 x 10(5) even after the 4th recycle. DTP was also found to be a promising solid acid catalyst for the intramolecular rearrangement of BPE giving 2-BP.

10aAcidity tuning10aCatalytic cleavage10aHydroxyalkylation10aIntramolecular rearrangement10asolid acid catalysts1 aRode, C., V.1 aGarade, Ajit, C.1 aChikate, Rajeev, C. uhttp://library.ncl.res.in/content/solid-acid-catalysts-modification-acid-sites-and-effect-activity-and-selectivity-tuning-002011nas a2200229 4500008004100000022001400041245010700055210006900162260007500231300001200306490000700318520115700325653001401482653002501496653001901521653001501540653002501555653002401580100002101604700002801625856012801653 2011 eng d a1571-101300aBiodiesel production from vegetable oils and animal fat over solid acid double-metal cyanide catalysts0 aBiodiesel production from vegetable oils and animal fat over sol a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGER/PLENUM PUBLISHERScSEP a145-1600 v153 a

Biodiesel comprises of fatty acid alkyl esters prepared from vegetable oils or animal fat by esterification/transesterification with short-chain alcohols (methanol or ethanol, for example). It is a biodegradable renewable fuel. Its production is growing exponentially due to greater concerns about environmental protection and depletion of fossil fuel resources. Further, its production from non-edible oils and animal fat is more desirable than from edible oils due to lower cost of non-edible feedstocks and elimination of food verses fuel issues. Solid acid catalysts are ideal for conversion of such low-grade oils to biodiesel. Biodiesel from non-edible oils can be produced by two methods: (1) simultaneous esterification of fatty acids and transesterification of fatty acid glycerides and (2) hydrolysis of glycerides followed by esterification. This account reports the catalytic performance of solid, Fe-Zn double-metal cyanide (DMC) complexes and other acid catalysts in these transformations for biodiesel production. The factors influencing the catalytic performance of the solid acid catalysts in biodiesel production are discussed.

10aBiodiesel10aDouble-metal cyanide10aEsterification10aHydrolysis10asolid acid catalysts10atransesterification1 aSrinivas, Darbha1 aSatyarthi, Jitendra, K. uhttp://library.ncl.res.in/content/biodiesel-production-vegetable-oils-and-animal-fat-over-solid-acid-double-metal-cyanide-002641nas a2200229 4500008004100000022001400041245007700055210006900132260007100201300001200272490000600284520184300290653002202133653001202155653002602167653002102193653001102214653002502225100002402250700002902274856010802303 2015 eng d a2155-543500aLignin depolymerization into aromatic monomers over solid acid catalysts0 aLignin depolymerization into aromatic monomers over solid acid c a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJAN a365-3790 v53 a

It is imperative to develop an efficient and environmentally benign pathway to valorize profusely available lignin, a component of nonedible lignocellulosic materials, into value-added aromatic monomers, which can be used as fuel additives and platform chemicals. To convert lignin, earlier studies used mineral bases (NaOH, CsOH) or supported metal catalysts (Pt, Ru, Pd, Ni on C, SiO2, Al2O3, etc.) under a hydrogen atmosphere, but these methods face several drawbacks such as corrosion, difficulty in catalyst recovery, sintering of metals, loss of activity, etc. Here we show that under an inert atmosphere various solid acid catalysts can efficiently convert six different types of lignins into value-added aromatic monomers. In particular, the SiO2Al2O3 catalyst gave exceptionally high yields of ca. 60% for organic solvent soluble extracted products with 95 +/- 10% mass balance in the depolymerization of dealkaline lignin, bagasse lignin, and ORG and EORG lignins at 250 degrees C within 30 min. GC, GC-MS, HPLC, LC-MS, and GPC analysis of organic solvent soluble extracted products confirmed the formation of aromatic monomers with ca. 90% selectivity. In the products, confirmation of retention of aromatic nature as present in lignin and the appearance of several functional groups has been carried out by FT-IR and H-1 and C-13 NMR studies. Further, isolation of major products by column chromatography was carried out to obtain aromatic monomers in pure form and their characterization by NMR is presented. A detailed characterization of six different types of lignins obtained from various sources helped in substantiating the catalytic results obtained in these reactions. A meticulous study on fresh and spent catalysts revealed that the amorphous catalysts are preferred to obtain reproducible catalytic results.

10aaromatic monomers10aBiomass10acolumn chromatography10adepolymerization10alignin10asolid acid catalysts1 aDeepa, Ayillath, K.1 aDhepe, Paresh, Laxmikant uhttp://library.ncl.res.in/content/lignin-depolymerization-aromatic-monomers-over-solid-acid-catalysts-0