02067nas a2200229   4500008004100000022001400041245010500055210006900160260007300229300001200302490000800314520122600322653002101548653001201569653001501581653002401596653001201620100001901632700002301651700003301674856013001707       2007                        eng d  a1381-116900aButylation of toluene: influence of zeolite structure and acidity on 4-tert-butyltoluene selectivity0 aButylation of toluene influence of zeolite structure and acidity  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAR  a109-1160 v2653 a<p>Vapour phase alkylation of toluene with tert-butyl alcohol was studied over the large pore zeolites H beta, HY and HMCM-22. The influence of the acidity, reaction temperature, run duration, feed rate (WHSV) and molar ratio of the reactants on conversion of toluene and selectivity for 4-tertbutyl toluene was studied. Among the isomers formed during the reaction, the para-isomer was the predominant one, followed by the meta-isomer, while no ortho-isomer was found in the products due to steric factors. 4-tert-Butyl toluene selectivity decreases at higher temperatures, while going through a maximum in the 413-433 K temperature range. Zeolite HY with a high silica to alumina ratio (SiO2/Al2O3 = 80), that has strong acidity, but lower acid site density, possesses high activity for toluene conversion, high alkylation selectivity and also high para-selectivity. The improved para-selectivity of high silica HY zeolite is attributed to the low isomerization activity that results in the suppression of the secondary isomerization of 4-tert-butyl toluene. Both alkylation and selectivity are higher with feed mixtures containing a lower fraction of tert-butyl alcohol. (c) 2006 Elsevier B.V. All rights reserved.</p>10a4-t-butyltoluene10aAcidity10abutylation10alarge pore zeolites10aToluene1 aPai, Shivanand1 aGupta, Upendranath1 aChilukuri, Satyanarayana, V.  uhttps://library.ncl.res.in/content/butylation-toluene-influence-zeolite-structure-and-acidity-4-tert-butyltoluene-selectivity01804nas a2200241   4500008004100000022001400041245008800055210006900143260007300212300001000285490000800295520097000303653001201273653001301285653001601298653001301314653002701327100001901354700001901373700001801392700003301410856011901443       2013                        eng d  a1387-181100aDehydration of fructose to 5-hydroxymethyl furfural over ordered AlSBA-15 catalysts0 aDehydration of fructose to 5hydroxymethyl furfural over ordered   aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcNOV  a38-460 v1813 a<p>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.</p>10aAcidity10aAlSBA-1510adehydration10afructose10aHydroxymethyl furfural1 aLucas, Nishita1 aKokate, Ganesh1 aNagpure, Atul1 aChilukuri, Satyanarayana, V.  uhttps://library.ncl.res.in/content/dehydration-fructose-5-hydroxymethyl-furfural-over-ordered-alsba-15-catalysts-0