@article { ISI:000241320000002, title = {Nature and mode of addition of phosphate precursor in the synthesis of aluminum phosphate and its influence on methanol dehydration to dimethyl ether}, journal = {Catalysis Communications}, volume = {7}, number = {10}, year = {2006}, month = {OCT}, pages = {745-751}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Four aluminum phosphate catalysts with Al/P = 1 were prepared by precipitation of mixture of aluminum nitrate and phosphate precursor (either phosphoric acid or diammonium hydrogen phosphate) with NH3 and precipitation of aluminum nitrate with NH3 followed by impregnation of phosphate precursor (either phosphoric acid or diammonium hydrogen phosphate). The catalysts were characterized, using different physico-chemical methods viz., BET-S.A., XRD, FT-IR, and NH3-TPD. Al-27 and P-31 MAS NMR spectroscopy was used to characterize selected catalysts in order to find out the presence of Al and P environments. The catalytic conversion of methanol to dimethyl ether was conducted over these catalysts in a temperature range of 448-548 K at atmospheric pressure. AIPO(4) prepared by precipitating the mixture of aluminum nitrate and (NH4)(2)HPO4 with aq. NH3 generated more number of moderate acid sites and showed higher methanol dehydration activity with 100\% selectivity to DME at 548 K. (c) 2006 Elsevier B.V. All rights reserved.

}, keywords = {Al-27 and P-31 MAS NMR, aluminum phosphate, dehydration, dimethyl ether, Methanol, NH3-TPD}, issn = {1566-7367}, doi = {10.1016/j.catcom.2006.02.025}, author = {Kumar, V. Siva and Padmasri, A. H. and Satyanarayana, C. V. V. and Reddy, I. Ajit Kumar and Raju, B. David and Rao, K. S. Rama} } @article { ISI:000274954400005, title = {Gas-phase oxidant-free oxidation of cyclohexanol over V2O5-MoO3-M2O (M = Na, K, Cs) catalysts}, journal = {Indian Journal of Chemical Technology}, volume = {17}, number = {1}, year = {2010}, month = {JAN}, pages = {43-49}, publisher = {NATL INST SCIENCE COMMUNICATION-NISCAIR}, address = {DR K S KRISHNAN MARG, PUSA CAMPUS, NEW DELHI 110 012, INDIA}, abstract = {

Oxidant-free oxidation (dehydrogenation) of cyclohexanol is carried out in a down-flow integral laboratory scale reactor using different alkali doped catalysts. The effect of reaction temperature, contact time (W/F) and doping of alkali metals is studied to check its effect on nature of prominent products of the reaction (cyclohexanone and cyclohexene). At lower temperature the cyclohexanone prevails whereas at higher temperature cyclohexene is observed in prominence. Acid-modified catalysts (with boron and phosphorous) facilitated cyclohexene selectivity whereas alkali modified catalysts facilitated cyclohexanone selectivity. Calcination of sodium modified catalyst at different temperatures under static condition affect characteristic phase intensity and cyclohexanone selectivity. XRD investigation showed formation of different inorganic phases as the characteristic of dopant. Cesium modified catalyst showed better dehydrogenation activity.

}, keywords = {Cyclohexanol, dehydration, Dehydrogenation, Electronegativity, V2O5-MoO3}, issn = {0971-457X}, author = {Vyawahare, Y. K. and Chumbhale, Vilas R. and Pardhy, S. A. and Samuel, V. and Aswar, A. S.} } @article { ISI:000294374900020, title = {Heteropolyacid supported on montmorillonite catalyst for dehydration of dilute bio-ethanol}, journal = {Applied Clay Science}, volume = {53}, number = {2, SI}, year = {2011}, month = {AUG}, pages = {263-271}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Vapour phase dehydration of dilute bio-ethanol (EtOH) to ethylene (E) and diethyl ether (DEE) is industrially relevant. Ethylene is an important raw material for many petrochemical products and Diethyl ether (DEE) can be used as an alternative fuel. The efficacy of montmorillonite (K-10) and dodecatungestophosphoric acid (DTPA) supported on montmorillonite (DTPA/K-10), has been evaluated in the current work in the dehydration of dilute bio-ethanol (80\%m/m). The dehydration of ethanol and cracking of diethyl ether were studied independently. 30\% m/m DTPA/K-10 was found to be more active with 74\% ethanol conversion and 92\% ethylene selectivity at 250 degrees C in comparison with other acid catalysts used. The merit of the process lies in its use of dilute bio-ethanol, a new avenue for ethylene production from a non-petroleum feedstock. Kinetic interpretation has been made by studying the important process parameters by using 30\%m/m DTPA/montmorillonite as the catalyst. The mechanism of the dehydration of ethanol reaction suggests that two types of sites are responsible. The dehydration of ethanol and cracking of diethyl ether are second order reactions with weak adsorption of species. (C) 2011 Elsevier B.V. All rights reserved.

}, keywords = {Bio-ethanol, dehydration, Diethyl ether, Ethylene, Heteropolyacid}, issn = {0169-1317}, doi = {10.1016/j.clay.2011.03.006}, author = {Bokade, Vijay V. and Yadav, Ganapati D.} } @article { ISI:000325676500006, title = {Dehydration of fructose to 5-hydroxymethyl furfural over ordered AlSBA-15 catalysts}, journal = {Microporous and Mesoporous Materials}, volume = {181}, year = {2013}, month = {NOV}, pages = {38-46}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

5-Hydroxymethyl furfural is an important platform chemical. It is successfully synthesized from renewable carbohydrates using mesoporous AlSBA-15 catalysts under biphasic conditions. Fine tuning of the catalyst acidity is important to drive the reaction to give good yields of furan compound. Al-SBA-15 catalysts with different Si/Al ratios were prepared and characterized by XRD, Al-27 MASNMR, SEM, TEM, N-2 sorption, ICP-OES and TPD of ammonia. Results show that part of aluminium is substituted into tetrahedral positions. The catalyst with lower acid site density but medium to strong acid strength favours selective formation of HMF. Under the optimized conditions, HMF selectivity was as high as 88\% at 59 mol\% conversion of fructose. Leaching of part of aluminium occurs under hydrothermal conditions, if solvent mixtures containing water are used, while activity can be retained if DMSO is used as solvent. (c) 2013 Elsevier Inc. All rights reserved.

}, keywords = {Acidity, AlSBA-15, dehydration, fructose, Hydroxymethyl furfural}, issn = {1387-1811}, doi = {10.1016/j.micromeso.2013.07.015}, author = {Lucas, Nishita and Kokate, Ganesh and Nagpure, Atul and Chilukuri, Satyanarayana V.} } @article { ISI:000340152000016, title = {Facile synthesis of the isoquinoline alkaloids doryanine and oxyhydrastinine}, journal = {Synthesis-Stuttgart}, volume = {46}, number = {14}, year = {2014}, month = {JUL}, pages = {1954-1956}, publisher = {GEORG THIEME VERLAG KG}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

Starting from 4,5-(methylenedioxy)homophthalic acid, a concise and efficient synthesis of the isoquinoline alkaloids dory-anine and oxyhydrastinine is described via the corresponding homophthalimide utilizing a one-pot regioselective reductive dehydration and catalytic hydrogenation pathway.

}, keywords = {dehydration, homophthalic acid, homophthalimide, isoquinoline alkaloids, regioselective reduction}, issn = {0039-7881}, doi = {10.1055/s-0033-1341158}, author = {Jangir, Ravi and Gadre, Smita R. and N. P. Argade} } @article { ISI:000334895800011, title = {Novel catalysts for valorization of biomass to value-added chemicals and fuels}, journal = {Journal of Chemical Sciences}, volume = {126}, number = {2, SI}, year = {2014}, note = {21st National Symposium on Catalysis (CATSYMP), CSIR Indian Inst Chem Technol, Hyderabad, INDIA, FEB 11-13, 2013}, month = {MAR}, pages = {403-413}, publisher = {Catalysis Soc India}, address = {C V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIA}, abstract = {

Key furan compounds such as 5-hydroxymethylfurfural (HMF), 2,5-furandicarboxylic acid (FDCA) and 2,5-dimethylfuran (DMF) were synthesized from renewable feedstocks. Dehydration of fructose was carried out in biphasic conditions employing several solid acid catalysts by targeting selective formation of HMF. Its selectivity is linearly dependent on total acidity clearly revealing that lower acidity favours selective formation of HMF. Oxidation and hydrogenolysis of HMF has been explored using 2 wt\% Ru-K-OMS-2. The catalysts used for each transformation were subjected to detailed characterization using XRD, BET surface area, temperature-programmed desorption and transmission electron microscopy. The effect of various reaction parameters was also investigated for obtaining high yields of desired chemical intermediates. High FDCA yields of 93.4 mol\% and 66 mol\% were achieved in alkaline and base-free conditions, respectively. The 2 wt\% Ru-K-OMS-2 is a versatile catalyst as it also catalyses HMF hydrogenolysis giving 33 mol\% of DMF. Thus, utility of various novel materials as catalysts has been demonstrated in the multistep transformations of hexoses to furan-based fuels and chemicals.

}, keywords = {2, 5-dimethylfuran, 5-furan dicarboxylic acid, 5-hydroxymethyl furfural, dehydration, fructose}, issn = {0974-3626}, author = {Lucas, Nishita and Kanna, Narasimha Rao and Nagpure, Atul S. and Kokate, Ganesh and Chilukuri, Satyanarayana V.} } @article {45644, title = {Application of glucose derived magnetic solid acid for etherification of 5-HMF to 5-EMF, dehydration of sorbitol to isosorbide, and esterification of fatty acids}, journal = {Tetrahedron Letters}, volume = {57}, year = {2016}, month = {SEP }, pages = {4398-4400}, type = {Article}, abstract = {

In this study, the catalytic activity of Glu-Fe3O4-SO3H was evaluated for three acid catalyzed reactions: etherification of 5-hydroxymethylfurfural (5-HMF) to 5-ethoxymethylfurfural (5-EMF) in ethanol, dehydration of sorbitol to isosorbide, and esterification of fatty acids with good yields and selectivity. Moreover, the catalyst can be easily separated from the reaction with an external magnetic force and reused at least five times without a significant decrease in catalytic activity. (C) 2016 Elsevier Ltd. All rights reserved.

}, keywords = {dehydration, Esterification, etherification, Magnetic}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2016.08.061}, author = {Thombal, Raju S. and Jadhav, Vrushali H.} } @article {47002, title = {Integration of heterogeneous acid and base catalysis for clean synthesis of jet-fuel precursor from carbohydrates}, journal = {ChemistrySelect}, volume = {5}, year = {2020}, month = {JAN }, pages = {392-400}, type = {Article}, abstract = {

C-12 branched alkane fuel precursor was produced from carbohydrates using an efficient integrated solid acid and base catalysis approach involving: i) isomerisation-dehydration of carbohydrates to 5-(hydroxymethyl)furfural (HMF) over solid acid catalyst having both Lewis and Bronsted sites) in a biphasic MIBK (methylisobutylketone): water + DMSO solvent system and ii) Claisen-Schmidt condensation of crude HMF with MIBK over solid base catalyst. Initially, high yield of jet fuel precursor, (E)-1-(5-(hydroxymethyl)furan-2-yl)-5-methylhex-1-en-3-one from pure HMF and MIBK was achieved over basic CaMgAl(231) catalyst. The glucose dehydration to HMF was optimized in biphasic MIBK: H2O-NaCl: DMSO (8:1.5:0.5; v/v/v) system, with complete glucose conversion and 42\% HMF yield over Zr-Mont possessing both Lewis and Bronsted acid sites. In an integrated dehydration + Claisen-Schmidt condensation sequence, Zr-Mont catalyst was filtered off and the crude HMF with MIBK underwent Claisen-Schmidt condensation over CaMgAl(231) catalyst. The overall 32\% yield of Claisen-Schmidt condensation product was achieved from glucose. MIBK acting also as a product extractant, could be recovered upto 80\%.

}, keywords = {Claisen-Schmidt condensation, dehydration, integrated, jet-fuel precursor, renewable}, issn = {2365-6549}, doi = {10.1002/slct.201903735}, author = {Shinde, Suhas and Tarade, Komal and Mitra, Gaurav and Rode, Chandrashekhar} } @article {48741, title = {Direct conversion of N-acetyl-d-glucosamine to N-containing heterocyclic compounds 3-acetamidofuran and 3-acetamido-5-acetyl Furan}, journal = {Waste and Biomass Valorization}, volume = {14}, year = {2023}, month = {DEC}, pages = {4201-4214}, type = {Article}, abstract = {

Purpose Effectual waste utilization from plant as well as marine biomass has gained tremendous importance with reference to sustainability. The valorization of marine biomass produces value added compounds containing not only C, H, O but also renewable N atom in the skeleton which widens the scope for its exploration which may prove to be economically beneficial to the society. Heterogeneous catalytic transformation of marine biomass i.e. N-acetyl glucosamine (NAG) to N-substituted aromatic heterocyclic furan derivatives is reported for the very first time. Cost effective and stable metal oxide catalysts were deployed for the transformation. Catalyst screening study showed that La2O3 was found to be an excellent catalyst for N-acetyl glucosamine (NAG) dehydration which mainly produced 3-acetamidofuran (3AF). Methods The physicochemical properties of the metal oxide catalyst were investigated by various techniques such as XRD, FTIR, MeOH-FTIR, TPD, SEM, N-2 sorption studies and HR-TEM analysis for structure activity relationship. Results The effect of various reaction parameters such as catalyst concentration, reaction temperature, reaction time and solvent effect on dehydration of N-acetyl glucosamine has been studied in detail for higher yields. The results revealed that the presence of weak basic sites which are Bronsted in nature and nano pores present on the surface were responsible for improved dehydration of the chitin biomass to selectively yield 3-acetamidofuran (3AF). La2O3 catalyst showed optimum 50\% 3AF yield from N-acetyl glucosamine at 180 degrees C in 3 h. Conclusion Efficacious exploitation of marine biomass to value added chemicals using heterogeneous catalysts can be extensively exploited. Separation of N-substituted heterocyclic aromatics is the most innovative aspect of the current study. Thus, utilization of heterogeneous catalyst and renewable biomass as a raw material indicates a transition towards more sustainable and greener approach.{GRAPHICAL ABSTRACT

}, keywords = {3-acetamido-5-acetylfuran, 3-acetamidofuran, dehydration, heterogeneous catalysis, Lanthanum oxide, N-acetyl-D-glucosamine, renewable feedstock}, issn = {1877-2641}, doi = {10.1007/s12649-023-02127-2}, author = {Shaikh, Samrin S. and Patil, Chetana R. and Lucas, Nishita and Bokade, Vijay V. and Rode, Chandrashekhar V.} } @article {48952, title = {Dehydration of lactate to acrylate using alkaline earth metal modified hydroxyapetite}, journal = {Catalysis Letters}, volume = {154}, year = {2024}, month = {FEB}, pages = {569-581}, type = {Journal Article}, abstract = {

Acrylates/acrylic acid are important for polymer industry due to its very high volume applications in different sectors. Activity of Ba/Mg modified hydroxyapatite for vapour-phase dehydration of ammonium lactate with 100\% conversion and 60\% acrylate selectivity was attributed to fine tuning of acid/base properties and formation of surface Ba/Ca lactate species.

}, keywords = {acrylate, Alkaline earth metal, dehydration, Lactate, Modified hydroxyapetite}, issn = {1011-372X}, doi = {10.1007/s10562-023-04329-8}, author = {Doke, Dhananjay S. S. and Dongre, Mohan K. K. and Umbarkar, Shubhangi B. B.} } @article {49223, title = {Selective synthesis of renewable diesel fuel precursors via C-C condensation of biomass-derived furans using a niobium oxide nanocatalyst}, journal = {ACS SUSTAINABLE CHEMISTRY \& ENGINEERING}, volume = {12}, year = {2024}, month = {SEP }, pages = {15923-15934}, type = {Journal Article}, keywords = {2-Methylfuran, Catalysts, dehydration, NB2O5, RANGE ALKANES, solid acid, Valorization}, issn = {2168-0485}, doi = {10.1021/acssuschemeng.4c03886}, author = {Kumar, Mudavath Arun and Swapna, Bhattu and Kalbande, Pavan Narayan and Yalagandula, Lavanya and Singh, Satyapaul A. and Sudarsanam, Putla} }