Abstract: An improved method is provided for preparing a crystalline aluminosilicate zeolite having a high silica/alumina mole ratio which comprises adding a source of aluminum ions to a silica-rich amorphous reaction medium at a rate whereby the concentration of aluminum ions in the amorphous phase of the preparation is maintained at steady state during crystallization. Crystallization time is substantially shortened by the present improved method and zeolites synthesized by way of the present improved method exhibit improved steam stability.Also provided are improved crystalline aluminosilicate zeolites prepared by way of the present improved method of synthesis and organic compound conversion therewith.

Abstract: The lower monohydric alcohols and their ethers, especially methanol and dimethyl ether, are converted to a hydrocarbon mixture mostly ethylene, propylene and mononuclear aromatics, by co-feeding elemental oxygen and said alcohol and/or ether to a catalytic reactor that contains as catalyst a composite of antimony oxide and a crystalline aluminosilicate zeolite such as ZSM-5. Co-feeding elemental oxygen effectively inhibits the elution of antimony from the catalytic reactor.