Chemistry of hydrocarbon compounds – Unsaturated compound synthesis – By c content reduction – e.g. – cracking – etc.
Reexamination Certificate
1999-05-20
2001-09-11
Utech, Benjamin L. (Department: 1764)
Chemistry of hydrocarbon compounds
Unsaturated compound synthesis
By c content reduction, e.g., cracking, etc.
C585S654000, C585S653000, C585S650000, C208S134000, C208S135000, C208S113000, C208S114000, C208S118000
Reexamination Certificate
active
06288298
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to using silicoaluminophosphates (“SAPO”s) having unique silicon distributions and their use as naphtha cracking catalysts for cracking hydrocarbon feedstocks. More particularly, the SAPOs have a high silica:alumina ratio, and are prepared from microemulsions containing surfactants.
BACKGROUND OF THE INVENTION
Conventional microporous crystalline silicoaluminophosphates such as SAPO-11 may be prepared by hydrothermal crystallization of silicoaluminophosphate gels containing a molecular structure forming template. SAPOs are members of a class known as non-zeolitic molecular sieves. SAPO molecular sieves have a framework of AlO
4
, SiO
4
and PO
4
tetrahedra linked by oxygen atoms. The negative charge in the network is balanced by the inclusion of exchangeable protons or cations such as protonated amines or alkylamonium. The interstitial spaces of channels formed by the crystalline network enables SAPOs to be used as molecular sieves in a manner similar to zeolites, which are crystalline aluminosilicates.
More recently a new silicoaluminophosphates have been prepared that are isostructural with conventional SAPO-11, but having a dramatically higher silicon:aluminum ratio and appropriate silicon distribution. Such materials are prepared from microemulsions.
Conventional SAPOs may be used as catalysts in petroleum processing. For example, SAPO catalysts may be used in lubricating oil hydroconversion procedures, hydrocracking, dewaxing, and combinations thereof. Conventional SAPO catalysts may also be used in naphtha cracking processes for forming light olefins such as propylene.
There remains a need, though, for improved silicoaluminophosphates for use in hydrocarbon processing.
SUMMARY OF THE INVENTION
In one embodiment, the invention is a process for selectively producing C
2
to C
4
olefins, the process comprising contacting, under catalytic conversion conditions, a catalytically or thermally cracked naphtha containing paraffins and olefins with a catalytically effective amount of a catalyst composition containing a SAPO catalyst, the SAPO catalyst having a total silicon amount ranging from about 0.2 molar % to about 40 molar %, a total aluminum amount ranging from about 30 molar % to about 49.9 molar %, and a total phosphorus amount ranging from about 10 molar % to about 49.9 molar %, the molar percents being based on the total amount of aluminum, phosphorus, and silicon present in the composition, and the SAPO catalyst being isostructural with a SAPO-11 having the AEL structure and containing silicon, aluminum, and phosphorus, wherein
(a) the silicon present in the SAPO catalyst is distributed among silicon sites, each site having a first, a second, a third, and a fourth nearest neighbor position, and each position being independently occupied by one atom selected from silicon and aluminum, and
(b) the composition has a first number of silicon sites having silicon atoms in the four nearest neighbor positions (Si4Si), a second number of silicon sites having silicon atoms in three of the four nearest neighbor positions (Si3Si), and a third number of silicon sites having silicon atoms in two of the four nearest neighbor positions (Si2Si), wherein
(i) the sum of the first, second, and third number of silicon sites ranges from about 10 to about 80 molar %, and
(ii) the molar ratio of the sum of the third and second number of silicon sites to the first number of silicon sites ranges from about 0.7 to about 1.4, the molar % being based on the total number of silicon sites.
REFERENCES:
patent: 4440871 (1984-04-01), Lok
patent: 4499315 (1985-02-01), Garska et al.
patent: 4512875 (1985-04-01), Long et al.
patent: 4683050 (1987-07-01), Ward
patent: 4724066 (1988-02-01), Kirker
patent: 4734185 (1988-03-01), Pellet et al.
patent: 4791083 (1988-12-01), Pellet
patent: 4803184 (1989-02-01), Long et al.
patent: 4818739 (1989-04-01), Gortsema et al.
patent: 4826804 (1989-05-01), Shamshoum
patent: 4857495 (1989-08-01), Gortsema et al.
patent: 4859311 (1989-08-01), Miller
patent: 4859312 (1989-08-01), Miller
patent: 4859314 (1989-08-01), Pellet et al.
patent: 4880760 (1989-11-01), Pellet et al.
patent: 4906351 (1990-03-01), Pellet et al.
patent: 4913798 (1990-04-01), Gortsema et al.
patent: 4914067 (1990-04-01), Pellet et al.
patent: 4921594 (1990-05-01), Miller
patent: 4943424 (1990-07-01), Miller
patent: 4960504 (1990-10-01), Pellet et al.
patent: 4976846 (1990-12-01), Long et al.
patent: 4992160 (1991-02-01), Long et al.
patent: 5087347 (1992-02-01), Miller
patent: 5096684 (1992-03-01), Guth et al.
patent: 5139684 (1992-08-01), Miller
patent: 5149421 (1992-09-01), Miller
patent: 5185310 (1993-02-01), Degnan et al.
patent: 5208005 (1993-05-01), Miller
patent: 5300277 (1994-04-01), Kresge et al.
patent: 5360474 (1994-11-01), Lauth et al.
patent: 5413695 (1995-05-01), Miller
patent: 5472594 (1995-12-01), Tsang et al.
patent: 5486284 (1996-01-01), Degnan et al.
patent: 5723716 (1998-03-01), Brandes et al.
patent: 5730858 (1998-03-01), Olivier et al.
patent: 5770042 (1998-06-01), Galperin et al.
patent: 5804058 (1998-09-01), Grandvallet et al.
patent: 5831139 (1998-11-01), Schmidt et al.
patent: 5833837 (1998-11-01), Miller
patent: 5879655 (1999-03-01), Miller et al.
patent: 5888378 (1999-03-01), Kowalski
patent: 5989518 (1999-11-01), Tannous et al.
patent: 146384 (1990-06-01), None
K.J. Chao, et al.,Silicon species in a SAPO-5 molelcular sieve, Applied Catalysis, 72, (1991) 34-39, No Month.
M.J. Franco, et al., Study of SAPO-5 obtained from surfactant-containing gels: Part 1. Crystallization parameters and mechanism of Si substitution, Zeolites 15:117-123 (1995), No Month.
J. Agundez, et al., Synthesis of SAPOs from Microemulsions: A General Method to Obtain Materials with Enhanced Catalytic Activity (Abstract), 11th International Zeolite Conference, RP25, 1996, No Month.
J. Agundez, et al., Synthesis of SAPOs from Microemulsions: A General Method to Obtain Materials with Enhanced Catalytic Activity, Discussions on Zeolite and Microporous Materials, 1997, Hanrimwon Publishing Co., Seoul, Korea, No Month.
P. Meriaudeau, et al., Isomorphous substitution of silicon in the AIPO4 framework with AEL structure: n-octane hydroconversion, Microporous and Mesoporous Materials 22 (1998) 435-449, No Month.
Canos Avelino Corma
Chen Tan Jen
Chica Lara Antonio
Davis Stephen M.
Henry Brian Erik
ExxonMobil Chemical Patents Inc.
Preisch Nadine
Utech Benjamin L.
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