The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 06, 2001
Filed:
Feb. 10, 1999
Raymond Le Van Mao, Ville St-Laurent, CA;
David Ohayon, Montreal, CA;
Concordia University, Montreal, CA;
Abstract
Disclosed herein are thermally stable ZSM-5 zeolite materials. The novel materials having substantially uniform micropores narrower (about 0.49 nm) or wider (about 0.55 nm and above) than those of conventional ZSM-5 zeolite (0.52-0.54 nm). Also disclosed is a preparation method (desilication/reinsertion/stabilization or DRS) for converting conventional ZSM-5 zeolite materials to the thermally stable zeolite materials of the present invention. The method of the present invention comprises the steps of sequentially treating ZSM-5 zeolite with aqueous solutions of sodium carbonate and sodium hydroxide to obtain a desilication of the zeolite, reinserting some of the silicon species (mainly sodium orthosilicate and sodium pyrosilicate) which have been selectively removed from the zeolite framework during the desilication operation, and activating the resulting materials in air or in the presence of steam at high temperatures. The amount of the reinserted silicon species depends on the pore size wanted.