@article { ISI:000263491600023,
	title = {Selective hydroxyalkylation of phenol to bisphenol F over dodecatungstophosphoric acid (DTP) impregnated on fumed silica},
	journal = {Applied Catalysis A-General},
	volume = {354},
	number = {1-2},
	year = {2009},
	month = {FEB},
	pages = {176-182},
	publisher = {ELSEVIER SCIENCE BV},
	address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS},
	abstract = {<p>The catalyst activity of various solid acids, such as fumed Silica (SiO(2)) dodecatungstophosphoric acid (DTP), DTP impregnated on SiO(2), amberlyst-15 and montmorillonite KSF/0, was studied for the hydroxyalkylation of phenol to bisphenol F. A well-dispersed DTP on SiO2 catalyst was prepared by the wet impregnation method. The effect of DTP loading on SiO(2) was also compared with bulk DTP and other solid acid catalysts. 20\% DTP/SiO(2) catalyst gave the highest products yield of 34.2\% and selectivity of 90.1\% to bisphenol F, at 353 K and with a phenol-to-formaldehyde mole ratio of 5:1. Ammonia TPD studies of various catalysts showed that an appropriate combination of both strong and weak acid sites of DTP/SiO(2) Was mainly responsible, rather than only the stronger acidity of bulk DTP, for its highest catalytic activity and selectivity. The effect of various reaction parameters like mole ratio, catalyst concentration, temperature and reaction time on product yield and bisphenol F selectivity was also investigated. The catalyst recycle was established by catalyst activity testing. (C) 2008 Elsevier B.V. All rights reserved.</p>},
	keywords = {Bisphenol F, Hydroxyalkylation, NH(3)-TPD, Reaction pathways, solid acid catalysts},
	issn = {0926-860X},
	doi = {10.1016/j.apcata.2008.11.025},
	author = {Garade, Ajit C. and Kshirsagar, V. S. and Rode, C. V.}
}
@article { ISI:000279333000002,
	title = {Structure-activity studies of dodecatungstophosphoric acid impregnated bentonite clay catalyst in hydroxyalkylation of p-cresol},
	journal = {Catalysis Communications},
	volume = {11},
	number = {11},
	year = {2010},
	month = {JUN},
	pages = {942-945},
	publisher = {ELSEVIER SCIENCE BV},
	address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS},
	abstract = {<p>Bentonite clay impregnated with dodecatungstophosphoric acid (20\% DTP/BNT) showed an excellent activity, selectivity and stability [95\% product yield with 94\% selectivity to 2, 2{\textquoteright}-methylenebis (4-methylphenol), DAM] for the hydroxyalkylation of p-cresol with formaldehyde at 353 K and for a mole ratio of 5. Ammonia-TPD results showed that an increase in total concentration of acid sites from 4.9 of parent bentonite to 11.6 micromoles per surface area NH(3) (mu molS(-1) NH(3)) of 20\% DTP/BNT was due to a strong interaction of protons of bulk DTP with surface hydroxyl groups of BNT as evidenced by (31)P NMR studies. (C) 2010 Elsevier B.V. All rights reserved.</p>},
	keywords = {(31)P CPMAS NMR, Bentonite, Hydroxyalkylation, p-Cresol, surface modification},
	issn = {1566-7367},
	doi = {10.1016/j.catcom.2010.04.008},
	author = {Garade, Ajit C. and Kshirsagar, V. S. and Jha, Ajay and Rode, C. V.}
}
