4132-72-3Relevant articles and documents
Isopropylation of xylenes catalyzed by ultrastable zeolite Y (USY) and some other solid acid catalysts
Patra, Chitta Ranjan,Kumar, Rajiv
, p. 216 - 224 (2007/10/03)
The isopropylation of all three xylene isomers was carried out over ultrastable zeolite Y (USY) catalyst to give corresponding dimethyl (1-methylethyl) benzenes, or in other words dimethyl cumenes (DMCs), using isopropanol as alkylating agent. The effect of reaction temperature, space velocity, substrate-to-alkylating-agent molar ratio, and time-on-stream on conversion of xylene isomers and selectivity to dimethyl cumene was studied. Isopropylation of xylenes over USY gives quite high (80 to 95%) DMC selectivity among the dimethyl cumenes, along with a 70-90% yield of DMCs in total products with respect to limiting reagents, i.e., isopropylating agents at relatively low reaction temperatures (423 ± 10 K) and at quite high xylene conversions (85-97% of theoretical maximum value). The solid acid catalysts zeolites H-Y, H-beta, H-mordenite, as well as silica-alumina and sulfated zirconia, were included for comparative studies in the isopropylation of m-xylene.
Kinetics and Regioselectivity of the Autoxidation of o-Substituted Isopropyl Aromatics
Heinze, Antje,Lauterbach, Gerlinde,Pritzkow, Wilhelm,Schmidt-Renner, Wolfgang,Voerckel, Volkmar,Zewegsuren, Nansadyn
, p. 439 - 446 (2007/10/02)
The relative chain propagation constants and the regioselectivities of the oxidations of o-cymene and 2-isopropyl-1,4-dimethylbenzene were determined by competitive oxidations of the hydrocarbons with cumene.As expected, the reactivity of the tertiary C-H bond of the isopropyl group is considerably decreased by o-methyl groups.Also in α-isopropylnaphthalene a considerable decrease in the reactivity of the tertiary C-H bond takes place.The decrease of the chain propagation constants effects a decrease of the oxidabilities of o-substituted isopropyl aromatics.In the case of the methyl isopropyl benzenes the increase of the chain termination constants by primary peroxy radicals must also be taken into consideration.This results in a decrease of the oxidabilities which can be observed even in p-cymene (in comparison with cumene).