초록 ▼

Crystalline aluminosilicate zeolites having increased silica to alumina mole ratios are prepared by a process wherein a conventional crystalline aluminosilicate zeolite is treated to remove alumina from the crystal lattice. By-product non-framework amorphous alumina is then selectively removed from

Crystalline aluminosilicate zeolites having increased silica to alumina mole ratios are prepared by a process wherein a conventional crystalline aluminosilicate zeolite is treated to remove alumina from the crystal lattice. By-product non-framework amorphous alumina is then selectively removed from the zeolite either by using a blocking agent, to prevent removal of framework aluminum during a subsequent acid treatment, or by using a selective organic acid extracting agent. The invention is also directed to high silica crystalline zeolites prepared by the present process.

대표청구항 ▼

A process for increasing the silica to aluminum (Si/Al) mole ratio in the crystal lattice of a crystalline aluminosilicate zeolite, said process comprising: (1) hydrothermally treating said zeilite for a period of time sufficient to effect removal of alumina from said crystal lattice, thereby increa

A process for increasing the silica to aluminum (Si/Al) mole ratio in the crystal lattice of a crystalline aluminosilicate zeolite, said process comprising: (1) hydrothermally treating said zeilite for a period of time sufficient to effect removal of alumina from said crystal lattice, thereby increasing the Si/Al ratio of the zeilite and forming a non-framework amorphous phase alumina by-product on said zeolite; and (2) extracting the amorphous phase alumina selectively with respect to the alumina in said crystal lattice of said zeolite to produce a zeolite product substantially retaining its degree of framework crystallinity with respect to the dealuminized zeolite produced in step (1), said extracting step being carried out by one of the following processes: a) contacting the treated zeolite of step (1) with a solution of an organic acid selected from the group consisting of Clx F3-x COOH, RCF2 COOH or RCCl2 COOH, wherein x is 1, 2 or 3 and R is phenyl or an alkyl group having from 1 to 10 carbon atoms, for a sufficient time and under process conditions suitable to remove a substantial portion of the amorphous phase alumina from said zeolite; or alternatively b) loading the treated zeolite of step (1) with an organic blocking agent to block access to the framework aluminum centers of the zeolite, and contacting said blocked zeolite with a solution of an extracting agent for sufficient time and under process conditions suitable to remove a substantial portion of the amorphous phase alumina from said zeolite. The process of claim 1, wherein the zeolite product of step (2) is subsequently ionexchanged or treated with an additive. The process of claim 21, wherein the additive is a catalytic metal employed in hydrocracking, reforming, or hydrotreating.