@article { ISI:000230297800006,
	title = {tert-Butylation of p-cresol over WOx/ZrO2 solid acid catalysts},
	journal = {Journal of Molecular Catalysis A - Chemical},
	volume = {235},
	number = {1-2},
	year = {2005},
	month = {JUL},
	pages = {44-51},
	publisher = {ELSEVIER SCIENCE BV},
	type = {Article},
	address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS},
	abstract = {<p>The tert-butylation of p-cresol with tert-butanol was carried out over WO3/ZrO2 catalysts under flow conditions, The catalysts were prepared by wet impregnation method using zirconium oxyhydroxide and ammonium metatungstate. Catalysts with different WO3 loading (5-30 wt.\%) were prepared and calcined at 800 degrees C and catalyst with 15\% WO,, was calcined from 600 to 900 C. The catalysts were characterized by surface area, XRD, FTIR and TEM. The catalyst 15\% WO3/ZrO2 calcined at 800 degrees C found to be the most active in the reaction. The effect of temperature, space velocity and molar ratio of the reactants on the conversion of p-cresol and products selectivities were studied. Under the optimized reaction conditions of 130 degrees C, tert-butanol/p-cresol molar ratio of 3 and flow rate of 10 ml h(-1). p-cresol conversion was 69.8\% with selectivity to 2-tert-butyl-p-cresol 92.4\%, 2,6-di-tert-butyl-p-cresol 6.3\% and p-cresol tert-butyl ether 1.3\%. The catalytic activity is compared with sulfated zirconia, USY, H beta zeolites and montmorillonite K-10 under the optimized reaction conditions The activity of sulfated zirconia is lower than that of 15\% WO3/ZrO2 catalyst calcined at 800 C and other catalysts showed very low activity, (c) 2005 Elsevier B.V.. All rights reserved.</p>},
	keywords = {p-Cresol, tert-butylation, tungsten oxide, Zirconia},
	issn = {1381-1169},
	doi = {10.1016/j.molcata.2005.03.019},
	author = {Sarish, S. and Devassy, Biju M. and Halligudi, Shivaraj B.}
}
@article { ISI:000240365800049,
	title = {Heteropoly acid supported on titania as solid acid catalyst in alkylation of p-cresol with tert-butanol},
	journal = {Journal of Molecular Catalysis A-Chemical},
	volume = {256},
	number = {1-2},
	year = {2006},
	month = {AUG},
	pages = {324-334},
	publisher = {ELSEVIER SCIENCE BV},
	type = {Article},
	address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS},
	abstract = {<p>Butylation of p-cresol with tert-butanol was investigated on titania modified with 12-tungstophosphoric acid (TPA/TiO2) catalyst under vapor phase conditions. Catalysts with different TPA loadings (10-25 wt.\%) and calcination temperatures (650-750 degrees C) were prepared by suspending titanium hydroxide in methanol solution of TPA followed by drying and calcination. These catalysts were characterized by surface area, XRD, P-31 MAS NMR, XPS, NH3-TPD, and FTIR pyridine adsorption. XRD results indicated that the presence of TPA retarded the crystallization of titania and stabilized TiO2 in anatase phase. P-31 MAS NMR indicated the presence of TPA in various forms (dispersed, highly fragmented and Keggin intact). These catalysts showed both Bronsted and Lewis acidity, and 20\% TPA on TiO2 calcined at 700 degrees C (from here after words 20\% TT 700) had the highest Bronsted as well as total acidity. Further, the catalytic activities were examined in tert-butylation of p-cresol with tent-butanol. The catalytic activity depended on TPA coverage, and the highest activity corresponded to the monolayer of TPA on titania. The most active catalyst 20\% TT-700 gave 82\% conversion of p-cresol and 89.5\% selectivity towards 2-tert-butyl cresol (TBC), 2,6-di-tert-butyl cresol (DTBC) 7.5\% and cresol-tert-butyl ether (CTBE) 3\% under optimized conditions. The activity was always higher than that of WO3/ZrO2, sulfated zirconia (SZ), USY, H-beta zeolites and montmorillonite K-10 (K-10mont) under similar conditions. (c) 2006 Elsevier B.V. All rights reserved.</p>},
	keywords = {2, 2-tert-butyl-p-cresol, 6-di-tert-butyl-p-cresol, Alkylation, heteropoly acid, p-Cresol, tert-butanol, titania},
	issn = {1381-1169},
	doi = {10.1016/j.molcata.2006.05.024},
	author = {Kumbar, Suresh M. and Shanbhag, G. V. and Lefebvre, F. and Halligudi, Shivaraj B.}
}
