01480nas a2200229 4500008004100000022001400041245006400055210006300119260007300182300001200255490000700267520072400274653001600998653002701014653002201041653002001063653001601083100002101099700002001120700001701140856009301157 2009 eng d a0169-131700aMontmorillonite for selective hydroxyalkylation of p-cresol0 aMontmorillonite for selective hydroxyalkylation of pcresol aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJAN a113-1170 v433 a

Performances of montmorillonite titanium silicate (TS-1) and dodecatungstophosphoric acid (DTP) were compared for the hydroxyalkylation of p-cresol into dihydroxydiarylmethane (DAM). Ammonia TPD studies of various catalysts showed that an appropriate combination of both strong and weak acid sites of montmorillonite was mainly responsible rather than only the stronger acidity of bulk DTP for its highest catalytic activity for selective hydroxyalkylation of p-cresol to DAM. The selectivity to DAM could be enhanced by adjusting reaction conditions like mole ratio of p-cresol to formaldehyde, reaction temperature, catalyst concentration, solvent and reaction time. (C) 2008 Elsevier B.V. All rights reserved.

10aAmmonia TPD10aDihydroxydiarylmethane10aHydroxyalkylation10aMontmorillonite10aSolid acids1 aGarade, Ajit, C.1 aMate, Vivek, R.1 aRode, C., V. uhttp://library.ncl.res.in/content/montmorillonite-selective-hydroxyalkylation-p-cresol-001825nas a2200265 4500008004100000022001400041245014000055210006900195260007300264300001200337490000800349520081600357653001501173653002001188653003801208653003101246653001401277653001101291100002801302700002101330700002401351700002901375700002501404856013001429 2010 eng d a1387-181100aMicro-/meso-porous stannosilicate composites (Sn-MFI/MCM-41) via two-step crystallization process: process parameter-phase relationship0 aMicromesoporous stannosilicate composites SnMFIMCM41 via twostep aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcDEC a115-1250 v1363 a

Sn-MFI/MCM-41 composite material was successfully synthesized by monitoring the re-crystallization time in a simple two-step crystallization process. The length of period allowed for the recrystallization of the precursor species was found to be a controlling factor to achieve either the end members viz. Sn-MCM-41 and Sn-MFI or Sn-MFI/MCM-41 composite material. Powder XRD, FTIR, SEM, TEM, nitrogen sorption measurement, DRUV-vis and hydroxyalkylation of p-cresol reaction were used as the characterization tools. Attempts were also made to establish the relationship between type of phase formed and the process parameters such as aging time, re-crystallization temperature, time and molar ratios of TPAOH/SiO(2), CTMABr/SiO(2) and SiO(2)/SnO(2) in the gel. (C) 2010 Elsevier Inc. All rights reserved.

10acomposites10aCrystallization10aMicro-/meso-porous stannosilicate10ap-Cresol hydroxyalkylation10aSn-MCM-4110aSn-MFI1 aNiphadkar, Prashant, S.1 aGarade, Ajit, C.1 aJha, Ratnesh, Kumar1 aRode, Chandrashekhar, V.1 aJoshi, Praphulla, N. uhttp://library.ncl.res.in/content/micro-meso-porous-stannosilicate-composites-sn-mfimcm-41-two-step-crystallization-process-001838nas a2200181 4500008004100000022001400041245009700055210006900152260007100221300001400292490000700306520113400313100001401447700002101461700002601482700002901508856011901537 2012 eng d a0888-588500aMCM-41 supported phosphotungstic acid for the hydroxyalkylation of phenol to phenolphthalein0 aMCM41 supported phosphotungstic acid for the hydroxyalkylation o a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAR a3916-39220 v513 a

A novel application of phosphotungstic acid, H3PW12O40 (PWA) supported on MCM-41 molecular sieve as a solid acid catalyst has been demonstrated for the synthesis of phenolphthalein by hydroxyalkylation of phenol and phthalic anhydride. PWA/MCM-41 (20%) showed the highest activity as compared to that of parent PWA and MCM-41 individually, due to the excellent dispersion of PWA on MCM-41 leading to the redistribution of Bronsted and Lewis acid sites on MCM-41. The effect of PWA loading on phthalic anhydride conversion and phenolphthalein selectivity was also studied. All these prepared catalysts were characterized by XRD, N-2 adsorption-desorption isotherm, pyridine-FTIR, and NH3-TPD. The effect of various reaction parameters, namely, mole ratios, catalyst concentration, temperature, reaction time, and percentage of PWA present in the catalysts on conversion and selectivity of products has been also investigated. The utility of 20% PWA/MCM-41 catalyst was established by its efficient activity for hydroxyalkylation of phenol and p-cresol with formaldehyde to the corresponding dihydroxydiarylmethane products.

1 aJha, Ajay1 aGarade, Ajit, C.1 aMirajkar, Subhash, P.1 aRode, Chandrashekhar, V. uhttp://library.ncl.res.in/content/mcm-41-supported-phosphotungstic-acid-hydroxyalkylation-phenol-phenolphthalein-001797nas a2200181 4500008004100000022001400041245010100055210006900156260007100225300001400296490000700310520108200317100001401399700002301413700002101436700002901457856012901486 2013 eng d a0888-588500aMagnetically separable single-site Ti-Fe3O4@MCM-41 catalyst for selective epoxidation of olefins0 aMagnetically separable singlesite TiFe3O4MCM41 catalyst for sele a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJUL a9803-98110 v523 a

Magnetically separable Ti-Fe3O4@MCM-41 (Ti-MS) catalysts were prepared by postgrafting Ti with varying loading on mesoporous silica containing dispersed magnetite. The hexagonal structure of Ti-MS catalysts with a periodicity in the pores and a highly ordered hexagonal matrix was established by X-ray diffraction and transmission electron microscopy, while diffuse reflectance UV showed the isolated tetrahedral Ti species coordinated with O2-. From the Fourier transform infrared studies, the extent of Ti-O-Si linkage was found to increase with increase in Ti-loading from 1 to 5 wt %beyond which (10%), the intensity of Ti-O-Si band decreased due to the polymerization of the Ti on the silica surface. Silanol groups on the surface of silica interact with the precursor Ti((OPr)-Pr-i)(4) to give site isolated tetrahedral Ti-species responsible for complete selectivity to the epoxide in the epoxidation of cyclooctene. The magnetic property facilitated easy recovery of the catalyst for its successful eight recycles showing its stability under reaction conditions.

1 aJha, Ajay1 aPatil, Chetana, R.1 aGarade, Ajit, C.1 aRode, Chandrashekhar, V. uhttp://library.ncl.res.in/content/magnetically-separable-single-site-ti-fe3o4mcm-41-catalyst-selective-epoxidation-olefins-001945nas a2200229 4500008004100000022001400041245009200055210006900147260007300216300001200289490000700301520114400308653002701452653002001479653001201499653001601511100001401527700002101541700001501562700001701577856012101594 2013 eng d a0169-131700aMetal cation-exchanged montmorillonite clay as catalysts for hydroxyalkylation reaction0 aMetal cationexchanged montmorillonite clay as catalysts for hydr aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAPR a141-1460 v743 a

Several solid acid catalysts were prepared by exchanging metal cations such as Zn2+, Fe3+ and Al3+ with montmorillonite clay. Among these, Al-montmorillonite showed the highest acidity determined by the pyridine-IR as well as NH3-TPD methods. A systematic comparison of the performance of these catalysts along with parent montmorillonite was carried out for the hydroxyalkylation of p-cresol with formaldehyde to give 2, 2'-methylenebis (4-methyl phenol) (DAM). It was found that the activity of these catalysts was in accordance with the increase in acidity of parent montmorillonite after the exchange of cations in the order of Zn2+, Fe3+ and Al3+. The selectivity pattern was also influenced by the exchanged cations. Since Al-montmorillonite showed the highest conversion of 51% with 98% selectivity to DAM, the effects of various reaction parameters, namely, mole ratio, catalyst concentration, temperature, reaction time on conversion and selectivity pattern were also studied using the same catalyst This catalyst also showed an excellent stability as evidenced by its eight times reuse. (C) 2012 Published by Elsevier B.V.

10aCations-exchanged clay10aMontmorillonite10aNH3-TPD10aPyridine-IR1 aJha, Ajay1 aGarade, Ajit, C.1 aShirai, M.1 aRode, C., V. uhttp://library.ncl.res.in/content/metal-cation-exchanged-montmorillonite-clay-catalysts-hydroxyalkylation-reaction-0