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Titolo:
Mesoporous solid acid catalysts: relationship between amine TPD data and catalytic activities
Autore:
Yiu, HHP; Brown, DR; Barnes, PA;
Indirizzi:
UnivD1uddersfield, Ctr Appl Catalysis, Dept Chem & Biol Sci, Huddersfield H Univ Huddersfield Huddersfield W Yorkshire England HD1 3DH Huddersfield H
Titolo Testata:
CATALYSIS LETTERS
fascicolo: 2-4, volume: 59, anno: 1999,
pagine: 207 - 211
SICI:
1011-372X(1999)59:2-4<207:MSACRB>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
PYRIDINE; CATION;
Keywords:
temperature-programmed desorption; TPD; ammonia; amine(s); mesoporous molecular sieve; MCM-41; AlMCM-41; exchangeable cation; surface acidity;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Engineering, Computing & Technology
Citazioni:
10
Recensione:
Indirizzi per estratti:
Indirizzo: Brown, DR UnivD1uddersfield, Ctr Appl Catalysis, Dept Chem & Biol Sci, Huddersfield H Univ Huddersfield Huddersfield W Yorkshire England HD1 3DH ld H
Citazione:
H.H.P. Yiu et al., "Mesoporous solid acid catalysts: relationship between amine TPD data and catalytic activities", CATAL LETT, 59(2-4), 1999, pp. 207-211

Abstract

The concentrations of surface acid sites on Al3+- and H+-exchanged AlMCM-41 catalysts have been measured by temperature-programmed desorption (TPD) of a series of primary, secondary and tertiary amines, and by adsorption of ammonia. Surface acid site concentrations have been compared with cation exchange capacities (CEC's) and catalytic activities in the alkylation of toluene with benzyl alcohol. The results show that the catalytic activities ofthe two ion-exchanged forms of the AlMCM-41 are similar. This is reflectedin the acid site concentrations measured with tri-n-butylamine, and to a lesser extent tri-i-butylamine, which are similar for both ion-exchanged forms of the catalyst, and close to the CEC. Acid site concentrations measuredwith smaller amines and ammonia are similar to those based on tributylamine TPD for H+-exchanged AlMCM-41, but the Al3+ form of the catalyst appears to chemisorb significantly more of the smaller amines and ammonia, resulting in higher than expected acid site concentrations when these adsorbates are used. Larger amines than the tributylamines show very low chemisorption capacities on both forms of AlMCM-41, and appear to access only a small proportion of the surface acid sites. The primary amines tested show poor separation of chemisorbed and physisorbed amine in TPD experiments, making the determination of acid site concentration difficult. The results illustrate the importance of choosing an appropriate amine in using TPD to measure catalyst surface acidities.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 19/09/20 alle ore 08:28:33