Claims
- 1. A continuous alkylation process for producing high octane gasoline comprising effecting reaction of an isoparaffin containing from 4 to 20 carbon atoms with an olefin containing from 2 to 12 carbon atoms at from about -40.degree. to about 500.degree. C. and at a pressure in the range of subatmospheric to about 5000 psig using a hydrocarbon feed wherein a molar ratio of the isoparaffin to the olefin in the hydrocarbon feed is from about 0.5:1 to about 200:1 in contact with a composite catalyst comprising a Lewis acid with a non-zeolitic solid inorganic oxide in the presence of water wherein a molar ratio of the water to said Lewis acid is less than about 1:1.
- 2. The process of claim 1, wherein the isoparaffin contains from 4 to 6 carbon atoms and the olefin contains from 2 to 6 carbon atoms.
- 3. The process of claim 1, wherein the Lewis acid is BF.sub.3, BCl.sub.3, SbF.sub.5 and/or AlCl.sub.3.
- 4. The process of claim 1, wherein the Lewis acid is BF.sub.3.
- 5. The process of claim 1, wherein the inorganic de is SiO.sub.2 or Al.sub.2 O.sub.3.
- 6. The process of claim 1, wherein the catalyst is BF.sub.3 /SiO.sub.2.
- 7. The process of claim 1, wherein the reaction is conducted under sufficient pressure to maintain at least one of the reactants in the liquid phase.
- 8. The process of claim 1, wherein the molar ratio of the isoparaffin to the olefin is from 5:1 to about to 25:1.
- 9. The process of claim 1, wherein the isoparaffin is isobutane and the olefin is propylene and/or butenes.
- 10. The process of claim 1, wherein the water and/or water-producing material is cofed with the reactants.
- 11. The process of claim 10, wherein the amount of water ranges from about 0.1 ppmw to about 1 weight percent based upon the total hydrocarbon feed rate.
- 12. The process of claim 10, wherein the amount of water ranges from about 0.1 ppmw to about 500 ppmw based upon the total hydrocarbon feed rate.
- 13. The process of claim 1, wherein water is added intermittently to the reaction.
- 14. The process of claim 1, wherein the reaction temperature is from about -40.degree. C. to about 250.degree. C.
- 15. The process of claim 1, wherein the weight hourly space velocity of the olefin is from about 0.01 to about 100.
- 16. The process of claim 1, wherein the Lewis acid is present in an amount in excess of that required to saturate the non-zeolitic solid inorganic oxide.
- 17. The process of claim 1, wherein the molar ratio of the isoparaffin to the olefin is from about 0.5:1 to about 5:1.
- 18. A continuous alkylation process for producing high octane gasoline comprising effecting reaction of an isoparaffin containing from 4 to 20 carbon atoms with an olefin containing from 2 to 12 carbon atoms at from about -40.degree. C. to about 250.degree. C. and at a pressure from about subatmospheric to about 500 psig using a reaction mixture containing about 0.1 ppmw to about 500 ppmw H.sub.2 O based on total hydrocarbon feed and having a molar ratio of the isoparaffin to the olefin from about 5:1 to about 25:1 in contact with a composite catalyst comprising BF.sub.3 with a non-zeolitic solid inorganic oxide.
- 19. The process of claim 18, wherein the Lewis acid is present in an amount in excess of that required to saturate the non-zeolitic solid inorganic oxide.
RELATED APPLICATIONS
This application contains related subject matter with applications Ser. No. 219,130, now abandoned, entitled Heterogeneous Isoparaffin/Olefin Alkylation Process; and application Ser. No. 219,527, now U.S. Pat. No. 4,918,255, entitled Heterogeneous Isoparaffin/Olefin Alkylation Process with Isomerization, all filed of even date, July 15, 1988.
This application is a continuation-in-part of application Ser. No. 219,129, filed July 15, 1988, and now abandoned. All of the applications are hereby incorporated by reference.
The present invention relates to the art of improving octane rating of gasoline by continuously alkylating an isoparaffin with an olefin to provide an alkylate product useful as a high octane blending component in gasoline.
This invention results from a need to improve octane ratings for gasoline. Isoparaffin-olefin alkylation is a means to produce highly branced paraffins which effect the octane improvement, which is the objective of this invention.
Alkylation is a reaction in which an alkyl group is added to an organic molecule. Thus, an isoparaffin can be reacted with an olefin to provide an isoparaffin of higher molecular weight. Industrially, the concept depends on the reaction of a C.sub.2 to C.sub.5 olefin with isobutane in the presence of an acidic catalyst producing a so-called alkylate. This is a very valuable blending component in the manufacture of gasoline because of its high octane rating.
Traditionally, the process in the industry includes the use of hydrofluoric acid or sulfuric acid as catalysts under controlled temperature conditions. Low temperatures are utilized in the sulfuric acid process to minimize the side reaction of olefin polymerization, and the acid strength is generally maintained at 88 to 94% by the continuous addition of fresh acid and the continuous withdrawal of spent acid. The hydrofluoric acid process is less temperature-sensitive and the acid is easily recovered and purified.
The typical types of alkylation currently used to produce high octane gasoline blending components, that is, the hydrofluoric acid and sulfuric acid alkylation processes, have inherent drawbacks including environmental concerns, acid consumption and sludge disposal. With the increasing demands for octane and the increasing environmental concerns, it has been desirable to develop an alkylation process based on a solid catalyst system. The catalyst of the present invention offers a refiner a more environmentally acceptable and more selective alkylation process than the currently used hydrofluoric and sulfuric acid alkylation processes.
Although alkylation processes using liquid, acidic catalysts are commercially successful, inherent disadvantages arise, in addition to those mentioned above, in the use of such catalysts including handling and disposal of corrosive material.
Consequently, substantial efforts have been made to develop a viable isoparaffin-olefin alkylation process using a solid catalyst which is commercially acceptable.
U.S. Pat. No. 3,862,258 teaches an alkylation process using a catalyst comprising a macroreticular acid cation exchange resin and boron trifluoride. According to the patent, the life of such a catalyst can be extended by the presence in the reaction mixture of closely controlled amounts of water which can be added to the feed as water or as waterforming compound.
U.S. Pat. No. 4,384,161 describes a process of alkylating isoparaffins with olefins to provide alkylate using as a catalyst a large pore zeolite capable of absorbing 2,2,4-trimethylpentane and a Lewis acid such as boron trifluoride, antimony pentafluoride or aluminum trichloride. The use of a large pore zeolite in combination with the Lewis acid is reported to greatly increase the activity and selectivity of the zeolite thereby effecting alkylation with high olefin space velocity and low isoparaffin/olefin ratio. According to the patent, problems arise in the use of solid catalysts in that they appear to age rapidly and cannot perform effectively at high olefin space velocity and the patent teaches the above solution to rectify the problem utilizing a zeolite type catalyst.
The article entitled Fixed Bed Catalytic Process To Produce Synthetic Lubricants From Decene-1, Ind. Eng. Chem. Prod. Res. Dev., Vol. 22, No. 4 (1983), teaches oligomerizing olefins to produce fluids with lubricating properties using a silica-BF.sub.3 - water catalyst. The authors further teach that with this system much of the BF.sub.3 can be recycled to minimize BF.sub.3 consumption and disposal problems. The reference teaches that water is a necessary component of the system and that in its absence a BF.sub.3 -silica catalyst rapidly deactivates. The reference further teaches that for less reactive olefins, such as Decene-1, a useful degree of oligomerization is achieved only by adding a measurable quantity of an activator such as water or a primary alcohol to BF.sub.3. The authors further point out that other BF.sub.3 activators, such as esters, ketones, acids and anhydrides, have also been claimed to form good olefin oligomerization catalysts. The article states that the process disclosed there is to both minimize BF.sub.3 consumption and disposal problems to produce a product having excellent lubricating properties through use of a catalyst requiring an activator like water.
In U.S. Pat. No. 4,308,414, an olefin, such as 1-decene, is oligomerized in the presence of a three-component catalyst comprising boron trichloride, a minute amount of water and a particulate absorbent material such as silica to a lubricating product predominating in those oligomer fractions having viscosities within the lubricating oil range such as the trimer and tetramer.
U.S. Pat. No. 4,429,177 further relates to a method for making lubricating oil utilizing a catalyst comprising boron trifluoride, a minute amount of elemental oxygen and a particulate absorbent material such as silica. The reference points out that the two component catalysts comprising a solid absorbent and boron trifluoride gradually lose activity after a period of continued use, which aging cannot be conveniently corrected by increasing the boron trifluoride pressure. As a solution, the reference teaches that this aging can be essentially prevented if a minute amount of elemental oxygen is fed to the reactor.
U.S. Pat. No. 3,997,621 relates to oligomerization of olefins catalyzed by boron trifluoride which is controlled to yield desired trimer as a dominant lubricant product by adding small amounts of ester together with water or alcohol promoter.
U.S. Pat. No. 4,365,105, also relates to oligomerizing an olefin in the presence of three-component catalyst comprising a particulate solid absorbent, boron trifluoride and elemental oxygen to make lubricating oils.
U.S. Pat. No. 4,394,296 relates to a three-component catalyst used in making lubricating oils which comprises a particular silica absorbent with boron trifluoride and water absorbed on the silica.
U.S. Pat. No. 2,939,890 discloses a process for alkylating an aromatic hydrocarbon with an olefin-acting compound at alkylation conditions in the presence of an alkylation catalyst comprising boron trifluoride modified alumina. Subsequently, U.S. Pat. No. 3,131,230 discloses the importance of the presence of small amounts of water for maintaining catalyst activity. Both of these patents are limited to aromatic alkylation processes.
U.S. Pat. No. 2,804,491 relates to an isoparaffin/olefin alkylation to make gasoline at temperatures between -20.degree. and 150.degree. F. utilizing a two component catalyst comprising essentially excess BF.sub.3 with a "silica stabilized gel amumina". No activators are taught.
In the past, severe activity and stability problems have been noted for zeolite based systems. U.S. Pat. Nos. 3,251,902 and 3,893,942, as well as French Patent No. 1,598,716 and the article to Kirsh and Potts, Div. of Pet. Chem. A.C.S., 15, A109 (1970) exemplify these problems. Improved stability was noted when a Lewis acid such as BF.sub.3 was used in combination with macroreticular acid cation exchange resins as pointed out in U.S. Pat. No. 3,855,342. More recently, the use of BF.sub.3 in combination with large pore zeolites such as ZSM-4 and Beta has been reported to effectively catalyze isoparaffin/olefin alkylation reactions. See U.S. Pat. No. 4,384,161.
However, only applicants have achieved advantages compared to these previous teachings by use of a catalyst comprising Lewis acids, such as BF.sub.3, in combination with nonzeolitic solid inorganic oxides, such as SiO.sub.2 or Al.sub.2 O.sub.3, in the presence of controlled amounts of water to produce higher octane gasoline and to reduce catalyst aging compared to these earlier processes.
Thus, this invention overcomes the problems posed by the prior art in that catalyst aging is significantly reduced. The present process effects improved octane ratings for gasolines by utilizing a heterogeneous catalyst in the presence of water.
The preceding references are hereby incorporated by reference.
This invention relates to an alkylation process for producing high octane gasoline comprising effecting reaction of an isoparaffin containing from 4 to 20 carbon atoms with an olefin containing from 2 to 12 carbon atoms at from about -40.degree. C. to about 500.degree. C. and at a pressure in the range of subatmospheric to about 5000 psig using a hydrocarbon feed wherein the molar ratio of the isoparaffin to the olefin in the combined hydrocarbon feed is from about 0.5:1 to about 200:1 in contact with a composite catalyst comprising a Lewis acid with a nonzeolitic solid inorganic oxide in the presence of water.
This invention also relates to an alkylation process for producing high octane gasoline comprising effecting reaction of an isoparaffin containing from 4 to 20 carbon atoms with an olefin containing from 2 to 12 carbon atoms at from about -40.degree. C. to about 250.degree. C. and at a pressure from about subatmospheric to about 500 psig using a reaction mixture containing about 0.1 ppmw to about 500 ppmw H.sub.2 O based on total hydrocarbon feed and having a molar ratio of the isoparaffin to the olefin from about 5:1 to about 25:1 in contact with a composite catalyst comprising BF.sub.3 with a non-zeolitic solid inorganic oxide.
US Referenced Citations (14)
Foreign Referenced Citations (2)
| Number |
Date |
Country |
| 1118181 |
Nov 1961 |
DEX |
| 546406 |
Jul 1942 |
GBX |
Non-Patent Literature Citations (1)
| Entry |
| Fixed-Bed Catalytic Process to Produce Synthetic Lubricants from Decene-1, (Gulf Research and Development Co.), 1983 American Chemical Society. |
Continuation in Parts (1)
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Number |
Date |
Country |
| Parent |
219129 |
Jul 1988 |
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Patent Grant
4956518
