1995 Volume 21 Issue 6 Pages 1090-1095
Isomeriation of 1-methylnaphthalene has been carried out over various solid acid catalysts. A prolonged catalytic life was obtained by employing highly dealuminated HY zeolite as catalyst and methyltetralin (MT) as an additive to the feedstock. The optimum lifetime was obtained by HY zeolite whose unit cell constant was regulated between 24.30Å and 24.34Å Dealumination causes lower acid site density at the catalyst surface which inhibits the formation of heavier coke. The effect of MT can be attributed to its hydrogen donating properties. A higher selectivity to isomerization can be obtained in the presence of MT. Furthermore, diluent gas consumption can be minimized without shortening the catalytic life in the presence of MT. All other catalysts or additives had insufficient lifetime because of rapid formation of coke. In a long run test of isomerization, more than 6000 h of catalytic life was confirmed using the optimum catalyst and conditions.