Preparation of zeolite

Details Preparation of zeolite Preparation of zeolite

2000-09-27

2002-10-29

Sample, David (Department: 1755)

Chemistry of inorganic compounds

Zeolite

Organic compound used to form zeolite

C423S708000

Reexamination Certificate

active

06471940

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for preparing zeolite, particularly zeolite [Al]-SSZ-31.
2. Description of the Related Art
Zeolites are porous materials having regular and uniform micropores of about 0.36-0.74 nm as well as a large specific surface area. Accordingly, zeolite, when used to provide reaction sites, may provide a molecular shape-selective reaction. Particularly, an aluminum-containing zeolite of called [Al]-SSZ-31 has large pores and is a high silica zeolite so that it is expected to be useful for a molecular shape-selective reaction of a large aromatic compound such as alkylation reaction. Zeolites with a large pore size are also expected to be useful as molecular sieve films.
Although zeolite [Al]-SSZ-31 is made substantially from a silica material, it is usually prepared by first preparing boron-containing [B]-SSZ-31 followed by substituting aluminum for boron. To prepare [B]-SSZ-31, boron beta is first prepared and calcined, then an organic structure directing substance and a silica source are added thereto, and thereafter a hydrothermal reaction is effected to crystallize and obtain [B]-SSZ-31, as disclosed in U.S. Pat. No. 5,106,801.
However, this process requires a large amount of boron beta and a calcination step, which are not desired.
No direct process of preparation of [Al]-SSZ-31, containing aluminum and having effective acid points, is known.
An object of the present invention is to provide a process for preparing zeolite, particularly SSZ-31, more specifically [Al]-SSZ-31.
An other object is to provide a convenient process for preparing said zeolite.
A further object is to provide said zeolite having a high purity.
SUMMARY OF THE INVENTION
To attain the above and other objects, the present invention provides a process for preparing zeolite [Al]-SSZ-31, comprising the steps of: providing a mixture of a zeolite source, an aluminum-containing material, an organic structure directing substance, and water; drying said mixture to form a powdered dry gel; and contacting and reacting said dry gel with water steam at a saturated vapor pressure to produce an aluminum-containing zeolite [Al]-SSZ-31.
Preferably the organic structure directing substance is selected from the group consisting of N,N′-bis-triethyl-1,6-hexanediyl-diammonium dihydroxide, N,N′-bis-triethyl-1,7-heptanediyl-diammonium dihydroxide, N,N′-bis-triethyl-1,8-octanediyl-diammonium dihydroxide, N,N′-bis-triethyl-1,9-nonanediyl-diammonium dihydroxide, N,N′-bis-triethyl-1,10-decanediyl-diammonium dihydroxide, and their salts.
The present invention also provides a process for preparing zeolite, comprising the steps of: providing a mixture of a zeolite source, an organic structure directing substance selected from the group consisting of N,N′-bis-triethyl-1,6-hexanediyl-diammonium dihydroxide, N,N′-bis-triethyl-1,7-heptanediyl-diammonium dihydroxide, N,N′-bis-triethyl-1,8-octanediyl-diammonium dihydroxide, N,N′-bis-triethyl-1,9-nonanediyl-diammonium dihydroxide, N,N′-bis-triethyl-1,10-decanediyl-diammonium dihydroxide and their salts, and water; drying said mixture to form a powdered dry gel; and contacting and reacting said dry gel with water steam at a saturated vapor pressure to produce a zeolite.


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