Isobutane alkylation with C-4 olefins on a sulfonic solid acid catalyst system based on laminar clays

Natural clays were modified by means of the controlled attack of strong Bro nsted acids in aqueous solution. The variations of the surface acidity of t he solids, followed by LR of adsorbed pyridine and hammett indicators, indi cated a population of Bronsted type sites above 800 mu mol/g, while the sur face area increased from 23 up to 105 m(2)/g. A series of solids (ATZ-L, AT Z-A and ATZ-G) was activated using triffuoromethanesulfonic acid (CF3SO3H), then evaluated at the bench scale in a fixed bed reactor, both in Liquid a nd gas phase, using an iC(4)/C-4(=) molar ratio, which led to 5.5% trimethy lpentanes (TMP) against 35.9% of C-8(=) and 53.4% of heavier C-9(+) product s for the catalysts (ATZ-L) having higher acid strength, i.e. Ho approximat e to -9.3. For the solids having a moderate surface acid strength (Ho appro ximate to -4.4) the activation rate after 12h runs was about 70%, but the s olids having a higher acid strength, i.e. Ho = -5.6 and -9.3, showed a deac tivation rate almost null after 24 h runs. (C) 2001 Published by Elsevier S cience B.V.