PRODUCTION OF ANTIKNOCK ADDITIVE IN GASOLINE (METHYL tert-BUTYL ETHER, MTBE) USING ZEOLITE CATALYSTS

Sameh M. Aboul-Fotouh

Ain Shams University, Faculty of Education, Chemistry Department, P.O. Box 7016, Nasr City,
Cairo 11471, Egypt; Email: saboulfotouh@hotmial.com

Present address: Sana’a University, Faculty of Science, Chemistry Department, P.O. Box 13838, Maeen, Republic of Yemen, Sana’a.

Abstract

The etherification of a mixture of methanol and t-butanol (1:1 mol) on hydrogen-, fluorinated-, alumina–deficient and aluminum-exchanged forms of ZSM-5, mordenite and Y zeolites was carried out in a flow reactor operated at atmospheric pressure and temperature of 50-400 °C using a flow of nitrogen 20 cm³ min^-1. The effect of methanol/t-butanol molar ratio of 0.5-3.0 and carrier gas flow rates of 10-60 cm³ min^-1 was studied. The activities of these zeolite catalysts for MTBE production were correlated with their acid sites strength distribution, using temperature-programmed desorption (TPD) of ammonia in a differential scanning calorimeter (DSC), as well as with the channels opening dimensions and Si/Al ratio of the zeolites. It is shown that the high acidity and bulk Si/Al ratio has a marked influence on the formation for MTBE. The hydrophobic/hydrophilic character of the catalysts was also discussed. The alumina-dificient and fluorination of a zeolite increases its framework Si/Al ratio, thus increases its hydrophobicity, whereas Al-exchange may decrease this ratio and increases its hydrophilicity.

Keywords: methyl tert-butyl ether, MTBE, etherification, ZSM-5, mordenite, Y zeolite, catalyst