01567nas a2200229 4500008004100000022001400041245011700055210006900172260007100241300001400312490000600326520073200332653001301064653001801077653001901095653000901114653002801123653001201151100002301163700002901186856012201215 2013 eng d a2155-543500aEfficient, stable, and reusable silicoaluminophosphate for the one-pot production of furfural from hemicellulose0 aEfficient stable and reusable silicoaluminophosphate for the one a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcOCT a2299-23030 v33 a

Development of stable, reusable, and water tolerant solid acid catalysts in the conversion of polysaccharides to give value-added chemicals is vital because catalysts are prone to undergo morphological changes during the reactions With the anticipation that silicoaluminophosphate (SAPO) catalysts will have higher hydrothermal stability, those were synthesized, characterized, and employed in a one-pot conversion of hemicellulose. SAPO-44 catalyst at 170 degrees C within 8 h could give 63% furfural yield with 88% mass balance and showed similar activity up to at least 8 catalytic cycles. The morphological studies revealed that SAPO catalysts having hydrophilic characteristics are stable under reaction conditions.

10afurfural10aHemicellulose10ahydrophilicity10aSAPO10awater-tolerant catalyst10azeolite1 aBhaumik, Prasenjit1 aDhepe, Paresh, Laxmikant uhttps://library.ncl.res.in/content/efficient-stable-and-reusable-silicoaluminophosphate-one-pot-production-furfural-002436nas a2200157 4500008004100000022001400041245012800055210006900183260011000252300001600362490000600378520172400384100002302108700002902131856011802160 2013 eng d a2046-206900aInfluence of properties of SAPO's on the one-pot conversion of mono-, di- and poly-saccharides into 5-hydroxymethylfurfural0 aInfluence of properties of SAPOs on the onepot conversion of mon aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcJUL a17156-171650 v33 a

Synthesis of 5-hydroxymethylfurfural (5-HMF) from biomass derived mono-and poly-saccharides is gaining importance because of its usefulness in the preparation of important chemicals. In our work, we have synthesized several silicoaluminophosphate (SAPO) catalysts, and have shown that in the absence of any other pH modifying reagents, those are active in converting mono-and poly-saccharides into 5-HMF under biphasic reaction condition at 175 degrees C. Particularly, SAPO-44 catalyst showed the best activity in the conversion of fructose to yield 78% 5-HMF with 88% selectivity. On the contrary, all other catalysts showed lower yields (H-MOR: 63%, SAPO-5: 32%, 2DCT: 60%). Over SAPO-44, good yields for 5-HMF were observed when glucose (67%), maltose (57%), cellobiose (56%) and starch (68%) were used as substrates. Recycle study carried out with SAPO-44 catalyst in the fructose conversion reaction showed marginal decrease in the activity up to 3rd run and then afterwards constant activity was observed up to 5th run (1st: 78%, 2nd: 71%, 3rd: 66%, 4th: 65%, 5th: 65%). Catalyst characterizations revealed that SAPO catalysts have higher hydrophilic nature than H-MOR (Si/Al = 10) and hence it is postulated that this property may help in achieving better results. Further studies on the catalyst characterizations revealed that SAPO-44 undergoes modifications in its structure. However, ICP-OES data suggests that Al and/or P are not leached out in the solution indicating that change in local environment around elements is possible. The influence of acid amount, type of acid site etc. on the catalytic activity is discussed and found out that strong acid sites are required to boost the 5-HMF yields.

1 aBhaumik, Prasenjit1 aDhepe, Paresh, Laxmikant uhttps://library.ncl.res.in/content/influence-properties-sapos-one-pot-conversion-mono-di-and-poly-saccharides-5-001969nas a2200157 4500008004100000022001400041245008500055210006900140260011000209300001600319490000600335520130400341100002301645700002901668856011401697 2014 eng d a2046-206900aExceptionally high yields of furfural from assorted raw biomass over solid acids0 aExceptionally high yields of furfural from assorted raw biomass  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcMAY a26215-262210 v43 a

Development of stable and recyclable solid acid catalysts in the efficient valorisation of hemicellulose to yield C-5 sugars and furfural is vital to boost the prospects of using lignocelluloses for chemicals synthesis. Using an silicoaluminophosphate, namely SAPO-44, as a catalyst, an environmentally benign process of furfural synthesis from diversified real substrates (without any treatment or the need for separation of its components) is shown. In an efficient one-pot methodology, at 443 K and in the presence of a biphasic solvent system, selective conversions of hemicelluloses from raw biomass (bagasse, rice husk and wheat straw) to extraordinarily high yields of furfural of about 93% were attainable. Under similar reaction conditions, an 82% yield of furfural is also achievable directly from isolated hemicellulose within 10 h. Hydrophilic SAPO-44, having higher hydrothermal stability, showed similar activity for all the substrates for a minimum of up to 8 times in recycling runs. Various physicochemical characterizations (X-ray diffraction, thermogravimetric analysis-derivative thermogravimetry, temperature programmed desorption-NH3, N-2 sorption, solid-state nuclear magnetic resonance spectroscopy) of fresh and spent catalysts were used to improve SAPO-44 stability.

1 aBhaumik, Prasenjit1 aDhepe, Paresh, Laxmikant uhttps://library.ncl.res.in/content/exceptionally-high-yields-furfural-assorted-raw-biomass-over-solid-acids-001104nas a2200169 4500008004100000022001400041245011300055210006900168260011000237300001400347490000600361520036600367100002300733700002000756700002900776856012900805 2014 eng d a2044-475300aSilica and zirconia supported tungsten, molybdenum and gallium oxide catalysts for the synthesis of furfural0 aSilica and zirconia supported tungsten molybdenum and gallium ox aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcJUN a2904-29070 v43 a

SiO2 and ZrO2 supported W, Mo and Ga oxide catalysts were prepared by a sol-gel and wet-impregnation method. The 10 wt% WO3/SiO2 (sol-gel) catalyst showed 61 +/- 2% furfural yield from hemicellulose in a one-pot fashion for at least 8 cycles. Based on XRD, TPD and Hammett acidity characterizations, the catalyst structure-activity correlation was drawn.

1 aBhaumik, Prasenjit1 aKane, Tanushree1 aDhepe, Paresh, Laxmikant uhttps://library.ncl.res.in/content/silica-and-zirconia-supported-tungsten-molybdenum-and-gallium-oxide-catalysts-synthesis-002356nas a2200253 4500008004100000022001400041245011800055210006900173260010100242300001200343490000800355520142000363653002201783653001201805653001101817653001801828653001101846653002401857100002301881700002401904700002001928700002901948856012501977 2014 eng d a0974-362600aValue addition to lignocellulosics and biomass-derived sugars: an insight into solid acid-based catalytic methods0 aValue addition to lignocellulosics and biomassderived sugars an  aC V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIAbCatalysis Soc IndiacMAR a373-3850 v1263 a

For the synthesis of important platform chemicals such as sugars (xylose and arabinose) and furans (furfural and 5-hydroxymethylfurfural (HMF)) from carbohydrates (hemicellulose and fructose) solid acid catalysts are employed. Similarly, over solid acid catalysts, conversion of lignin into aromatic monomers is performed. It is observed that in the dehydration of fructose, because of higher hydrothermal stability, silicoaluminophosphate (SAPO) catalysts give better activity (78% HMF yield) compared with other solid acid catalysts (<63% HMF yield) at 175 degrees C. Particularly, SAPO-44 catalyst can be reused at least 5 times with marginal decrease in the activity. Zeolite, BUSY (Si/Al = 15) is active in the conversion of isolated (pure) hemicellulose to produce 41% C-5 sugars in water. The catalyst is also active in the selective conversion of hemicellulose from bagasse to yield 59% C-5 sugars. It is possible to obtain high yields of furfural (54%) directly from bagasse if instead of water, Water+toluene solvent system is used. Depolymerization of lignin using HUSY catalyst produced aromatic monomers with 60% yield at 250 degrees C. A detailed catalyst characterization study is performed to understand the correlation between catalyst activity and morphology. To understand the effect of impurities present in the substrate over solid acid catalysts, metal-exchange study is carried out.

10aaromatic monomers10aBiomass10afurans10aHemicellulose10alignin10asolid acid catalyst1 aBhaumik, Prasenjit1 aDeepa, Ayillath, K.1 aKane, Tanushree1 aDhepe, Paresh, Laxmikant uhttps://library.ncl.res.in/content/value-addition-lignocellulosics-and-biomass-derived-sugars-insight-solid-acid-based-000473nas a2200145 4500008004100000245003800041210003800079260004600117300000900163100002300172700002900195700001900224700001900243856006500262 2015 eng d00aConversion of biomass into sugars0 aConversion of biomass into sugars aCambridge, UKbRoyal Society of Chemistry a1-531 aBhaumik, Prasenjit1 aDhepe, Paresh, Laxmikant1 aDmitry, Murzin1 aOlga, Simakova uhttps://library.ncl.res.in/content/conversion-biomass-sugars01902nas a2200217 4500008004100000022001400041245009300055210006900148260007300217300001000290490000800300520114400308653001201452653001301464653001801477653001201495653001101507100002301518700002901541856011401570 2015 eng d a0920-586100aEffects of careful designing of SAPO-44 catalysts on the efficient synthesis of furfural0 aEffects of careful designing of SAPO44 catalysts on the efficien aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAUG a66-720 v2513 a

Considering the growing importance of furfural, it is necessary to develop a robust solid acid catalyst for the conversion of xylan (hemicelluloses) into furfural in a one-pot method. In this study, the effects of various components (Si, Al and P) and crystallization time on the preparation of acidic materials and their properties are extensively described. It is seen that with the increase in crystallization time (0, 48, 96, 176 h) during the synthesis of silicoaluminophosphate (SAPO-44), materials morphology changes from amorphous to AFI to CHA and the best activity for furfural synthesis (82%) from xylan was observed with SAPO-44 catalyst aged for 176 h. Since, acidity in the SAPO-44 is guided by the incorporation of Si in the ALPO framework, study on Si molar concentration (0.8, 1.0, 1.2, 1.4 and 1.6) in SAPO-44 was carried out and it was observed that SAPO-44 having 1.0 mole of Si content is the best catalyst for the xylan/xylose conversion to furfural. Catalyst structure-activity correlation is thoroughly defined with the help of several physico-chemical properties. (C) 2014 Elsevier B.V. All rights reserved.

10aBiomass10afurfural10aHemicellulose10aSAPO-4410aXylose1 aBhaumik, Prasenjit1 aDhepe, Paresh, Laxmikant uhttps://library.ncl.res.in/content/effects-careful-designing-sapo-44-catalysts-efficient-synthesis-furfural-001746nas a2200253 4500008004100000022001400041245006400055210006400119260008600183300001100269490000700280520093000287653002301217653001801240653001401258653001101272653001301283653001901296653000801315653002401323100002301347700002901370856009301399 2016 eng d a0161-494000aSolid acid catalyzed synthesis of furans from carbohydrates0 aSolid acid catalyzed synthesis of furans from carbohydrates a530 WALNUT STREET, STE 850, PHILADELPHIA, PA 19106 USAbTAYLOR & FRANCIS INCcJAN a36-1120 v583 a

The alternative feedstock, biomass (particularly lignocelluloses), having the profuse availability, is promising for the synthesis of several value-added chemicals which are currently obtained from fossil feedstock. In this article, the synthesis of two extremely significant furan chemicals viz. furfural and 5-hydroxymethylfurfural (HMF) are discussed. In the synthesis of furans from biomass, numerous challenges, i.e., use of edible sugars as substrates, selectivity to furans, their isolation in pure form, reuse of catalyst, environmental issues, etc., are perceived and in the recent past researchers tried to resolve those by developing advance methodologies. This article comprehensively summarizes the latest progress made in the above-mentioned areas and also provides commentary on the analyses of results, rationale for observed activity and mechanisms, etc. It also discusses future aspects of this work.

10aBiomass conversion10acarbohydrates10acellulose10afurans10afurfural10ahemicelluloses10aHMF10asolid acid catalyst1 aBhaumik, Prasenjit1 aDhepe, Paresh, Laxmikant uhttps://library.ncl.res.in/content/solid-acid-catalyzed-synthesis-furans-carbohydrates-001503nas a2200145 4500008004100000245012400041210006900165260000800234300001400242490000600256520091600262100002301178700002901201856012701230 2017 eng d00aFrom lignocellulosic biomass to furfural: insight into the active species of a silica-supported tungsten oxide catalyst0 aFrom lignocellulosic biomass to furfural insight into the active cJUL a2709-27160 v93 a

A sol–gel-synthesized silica-supported tungsten oxide catalyst that has Lewis acidity was characterized and employed as a solid acid catalyst in the synthesis of furfural directly from lignocellulosic biomass (isolated xylans and crop wastes). In a one-pot method, 71 % furfural formation from isolated xylan was possible using a water/toluene (1:2 v/v) biphasic solvent system at 170 °C after 10 h over 10 wt % WO3/SiO2. The WO3/SiO2 catalyst in the selective conversion of pentosan from crop wastes (bagasse, wheat straw, and rice husk) yielded 72–87 % furfural under the optimum reaction conditions. Additionally, the catalyst presented excellent recyclability in at least eight runs after simple water washing. From the catalyst characterization studies, it was suggested that silicotungstic-type acid species are anchored on the WO3/SiO2 catalyst that help to achieve a good catalytic activity.

1 aBhaumik, Prasenjit1 aDhepe, Paresh, Laxmikant uhttps://library.ncl.res.in/content/lignocellulosic-biomass-furfural-insight-active-species-silica-supported-tungsten-oxide