|Publication number||US3873634 A|
|Publication date||Mar 25, 1975|
|Filing date||Oct 17, 1973|
|Priority date||May 26, 1972|
|Publication number||US 3873634 A, US 3873634A, US-A-3873634, US3873634 A, US3873634A|
|Inventors||Hoffman David M|
|Original Assignee||Sun Ventures Inc|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (3), Referenced by (12), Classifications (7)|
|External Links: USPTO, USPTO Assignment, Espacenet|
United States Patent Hoffman PROMOTION OF ETHYLENE/ISOPARAF FIN ALKYLATION  Inventor: David M. Hoffman, Weston, Conn.
 Assignee: Sun Ventures, Inc., St. Davids, Pa.
 Filed: Oct. 17, 1973 [211 App]. No.: 407,398
Related [1.8. Application Data  Continuation-impart of Ser. No. 257.090, May 26,
UNITED STATES PATENTS 2,363,222 11/1944 Beyerstedt ..260/683.44
[ Mar. 25, 1975 6/1946 Schulze et al 260/683.44 7/1946 Axe 260/683,.44
Primary Examiner-Delbert E. Gantz Assistant Examiner-G. J. Crasanakis Attorney, Agent, or Firm-George L. Church; Donald R. Johnson; Stanford M. Back [5 7] ABSTRACT The rate of ethylene alkylation by isobutane can be promoted by carrying out the reaction simultaneously with the alkylation of a small amount of a higher weight olefin by isobutane; low temperatures and pressures using a BF .H PO complex as the catalyst, are employed.
16 Claims, No Drawings PROMOTION OF ETHYLENE/ISOPARAFF IN ALKYLATION CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of U.S. Ser. No. 257,090 filed May 26, 1972 by David M. Hoffman.
BACKGROUND OF THE INVENTION This invention relates to an improved process for the alkylation of a C or C monoolefin with a C C, isoparaffin in the presence of a BF H PO, catalyst. More particularly, this invention relates to an improved method of alkylating ethylene or propylene by the aforesaid paraffins by carrying out the reaction simultaneously with the alkylation of a small amount of a higher molecular weight monoolefin by said isoparaffin.
The alkylation of ethylene with isobutane using a BF H PO, complex as the catalyst is already known in the art. These methods, while they do produce some of the desired alkylate, are nevertheless characterized by relatively low yields and slow reaction rates.
U.S. Pat. No. 2,401,884 teaches the alkylation of higher olefins with isoparaffin, using an H PO BF catalyst, wherein said catalyst is first preheated or conditioned with small amounts ofa lower molecular weight olefin in order to stabalize this BF catalyst. This latter olefin, preferably ethylene, may be included in small amounts in the feed stream with the higher olefin which is to be alkylated. However, a means for improving the rate of alkylation of ethylene or propylene with isoparaffins is neither taught nor suggested by this patent.
SUMMARY OF THE INVENTION In accordance with the present invention, it has now been found that C or C monoolefins may be alkylated by C -C isoparaffins with marked increases in yields and rates when the reaction is carried out simultaneously, i.e. in combination with, the alkylation of a small amount of a different, higher molecular weight monoolefin by said isoparaffins, and when the catalyst employed is a 8P H PO, complex. Thus, for example, the alkylation of ethylene by isobutane simultaneously with the alkylation of butene-2 to form an alkylate containing large amounts of 2,3-dimethylbutane represents one preferred embodiment, but other alkylations such as the alkylation of propylene by isobutane in the presence of butylene may likewise be satisfactorily achieved in accordance with this novel process. The resulting alkylate mixtures comprising C C isoparaffins, particularly 2,3-dimethylbutane and trimethylpentanes, are useful as components in motor fuels.
DESCRIPTION OF THE INVENTION The reaction may conveniently be carried out using known alkylation methods and suitable apparatus at temperatures of from about -l0 to 50C, preferably 0 to C, and at pressures of from about 1 to 1,000 psi, depending upon the reactants employed, for periods of from about 0.05 to 1 hour. Although none of these parameters is particularly critical, it will be noted that advantageously and desirably the reaction is carried out at temperatures and presssures substantially below those ranges employed by the above-described prior art.
The principal monoolefin reactant to be alkylated is, as aforestated, preferably ethylene, although propylene may also be employed. Mixtures of these two olefins, or mixtures of these olefins with C -C paraffins, as for example a refinery stream boiling at less than 20C may also be used. In the case where such a mixture of light olefins containing large amounts of paraffins is used as the charge stock, not only do the paraffins not interfere with the reaction but actually the reaction serves as one convenient way of separating the olefins from these paraffins. In such a process the light olefins are alkylated to form a C and heavier alkylate from which any unreacted ethane, propane and n-butane are easily separated by distillation.
Although the preferred isoparaffin reactant is isobutane, it will be understood that any C -C paraffin or mixture thereof, having at least one tertiary carbon atom, may be employed in this process, as for example isopentane, methylcyclopentane or the like. The molar ratio of isoparaffin to ethylene or propylene should desirably be in the range of 1:1 to 100: 1, and preferably 10:1, in order to maintain a large excess of isoparaffin over the ethylene or propylene.
The other monoolefin which acts as a promoter for the alkylation of the ethylene by simultaneously alkylating it with the isoparaffin, together with the principal monoolefin, i.e. the ethylene or propylene must, of course, be a different olefin, and should be a higher molecular weight monoolefin in the C -C range. Included amongst these monoolefins, which serve to promote the alkylation reaction between the isoparaffin and first monoolefin, are propylene, butene-l,butene- 2, isobutylene, 2-methylbutine-2 and mixtures thereof, particularly mixtures comprising butene-l, butene-2 and isobutylene.
Although propylene can serve as the second monoolefin for purposes of accelerating the rate of ethylene alkylation, its own alkylation rate can also be accelerated by simultaneously alkylating it in the presence of a C, or higher olefin. It will be understood, as stated above with respect to the first monoolefin, that mixtures of the C -C monoolefins, or mixtures of these olefins with normal paraffins, perferably in the C C range, may also be employed. The molar ratio of the ethylene or propylene to the higher weight C to C monoolefin should desirably be at least 5:1, and preferably 10-2011, in order to maintain a substantial excess of ethylene or propylene over the C to C olefin at all times.
It will thus be understood from the foregoing that the amount of C to C olefin used will always be much smaller than the amount of ethylene of propylene employed, since more amounts of C to C olefin have been found unexpectedly, to serve as a promoter for the alkylation of ethylene. That is to say, the second olefin is not there for the principal purpose of being alkylated to form alkylate: it is only added for the purpose of increasing ethylene alkylation. Thus, although the second olefin is present in considerable smaller proportions than the ethylene, its presence causes a much larger number of moles of ethylene to be alkylated than the number of moles of higher olefin present, thereby demonstrating an unexpected catalyst-like role.
The BF;,. H PO, complex used as the catalyst for the novel process of this invention may be prepared in one or more ways, as described in U.S. Pat. No. 2,363,222 (supra). Thus, in one such method, a commercial grade of orthophosphoric acid ranging from about 60 to percent, with the remainder water, is contacted with E1 gas by bubbling the gas through the acid solution until there is no further change in weight of the solution. The resulting solution then comprises the BP H P catalyst.
Alternatively, the aforedescribed 85 percent orthophosphoric acid may be first contacted with sufficient P 0 to form the equivalent of 100 percent orthosphosphoric acid. To this composition is then added sufficient BF again by bubbling it through the solution until no more BFj; is taken up, to form the BF H PO complex. The amount of said catalyst employed in this process is generally about to 500 ccs per 100 cc of isoparaffin, and preferably 75 to 150 cc.
In the following examples, Example 1 illustrates the prior art method where ethylene and isobutane alone are alkylated. In Example 2, a comparative run where butene-2 is alkylated by isobutane in the absence of ethylene is also provided, together with one run (three samples) in accordance with the process of this invention. Examples 3 to 6 are likewise in accordance with the instant invention. When the results of Examples 3 to 6 are compared with the results in Examples 1 and 2, it will be very evident that a substantial increase in yields and rates is achieved over the prior art methods while at the same time employing the lower temperatures and pressures.
In each of the following examples run in accordance with the present process, the rate of introduction of the two different olefms was controlled in order to provide and continuously maintain, a substantial excess of ethylene of propylene over the C olefin within the aforedescribed parameters. This was achieved principally by maintaining a substantially fixed ethylene pressure and adding the butane compound slowly during the course of the reaction. That is to say, as long as excess pressure of ethylene or propylene is maintained, and the second olefin is fed slowly into the reaction zone, the mole ratio of principal olefin to second olefin remains high because the rate of alkylation of the second olefin is very fast and its concentration is always low in the reaction zone.
EXAMPLE 1 200 cc of H PO 100%).BF was emulsified with 200 cc of isobutane in a l-liter stirred Parr reactor at 10C while 60 to 80 psi pressure was maintained with ethylene. Samples were taken at 60 minute intervals and analyzed vs. an internal standard of n-octane with the following results:
Butene-2 (23.6g) in 75 cc of isobutane was added to an emulsion of 200 cc H PO (100%).BF and 150 cc of isobutane at 10C over a period of 48 minutes. During the entire reaction the pressure maintained between 60 4 to psi with ethylene. The alkylate was sampled at 55, 75 and 105 minutes after the start of butene addtion. A minute butene-2 alkylation without ethylene is given for comparison.
TIME 55 Min. 75 Min. Min. 100 Min.
Ethylene Pressure (psi) 60-80 6080 60-80 0 Alkylate Yield 88.5 96.3 112.7 46.9
(g) Product Composition 1C 5.8 5.3 4.7 5.7 2,3-DMB 2MP 29.8 30.6 29.3 3.1 3MP 1.3 1.2 1.0 0.5 C 5.6 5.8 6.4 4.4 TMPs 30.3 29.2 27.8 64. DMH 's 9.6 10.2 11.9 8.5 C 17.6 17.4 18.9 12.6
The above reactions were carried out at 5C and 20C with comparable results.
The data in these two examples indicate that during the addition of butene-2, the amount of alkylate formed is much greater than that formed separately by isobutane/ethylene and isobutane/butene-Z alkylation under the same conditions. Moreover, the increase in the alkylate is caused by an increase in the product that results from the alkylation of ehtylene with isobutane (Le. large amounts of 2,3-dimethylbutane are formed).
EXAMPLE 3 2-methylbutene-2 (22.0 g) in 60 cc of isobutane was added to an emulsion of 200 cc H PO (100 percent).BF and 140 cc of isobutane at 10C over a period of 38 minutes. During the entire reaction the pressure was maintained at between 60 to 80 psi with ethylene. The alkylate was sampled at 48 and 78 minutes after the start of olefin addition.
200 cc of H PO BF H O prepared by saturating 90 percent H PO with B1 was combined with cc of isobutane in a l-liter monel stirred reactor. The pressure was maintained'at 608O psi with ethylene as 22.5 g of butene-1 in 75 cc of isobutane was added over 40 minutes while maintaining the temperature at 10C. The alkylate was analyzed 50 and 70 minutes after the butene-l addition was started. Ethylene pressure was maintained throughout the entire sampling period.
Time 50 Minutes 70 Minutes Alkylate Yield (g) 44.8 46.1
(Wt%) 199 205 Product Composition (Wt%) iC 4.3 3.7 2,3-DMB 24.4 25.0 2MP 3MP 3.5 3.5 1 2.8 2.7 TMPs 33.9 33.8 DMHX'S 17.4 17.4 C 13.5 13.4
EXAMPLE 5 A mixture of 200 cc of H PO 100 percent).BF and 125 cc of isobutane was emulsified in a 1-liter Parr reactor at C. A mixture of 4.0 g isobutylene, 10.3 g butene-1 and 7.9 g propylene in 75 cc of isobutane was fed to the reaction simutaneously with 8.1 g of ethylene over a period of 52 minutes. The alkylate was analyzed 10, 30 and 50 minutes following the completion of the olefin addition.
Time following addition Yicld* (Wt /I) Product Composition (WW1) Yield based on total C -C olefin charged.
In accordance with the foregoing procedure, but adding butene-Z to the mixture of isobutylene and butene- 1, there is obtained a like alkylate product mixture in the C C range.
EXAMPLE 6 TIME Minutes 40 Minutes Yield (wt.% on iC 300 327 Composition (wt.%)
6 iC 8.4 7.6 2.3-DMB 2MP 33.5 34.8 3MP 0.7 0.7 C 's 6.4 6.2 TMP's 23.5 22.8 DMH s 7.9 8.5 C 19.3 19.3
The invention claimed is: 1. In the process for the alkylation of a first monoole- 10 fin comprising ethylene or propylene by C.,-C isoparaffins in the presence of BF H PO catalyst, the improvement wherein said alkylation is carried out simultaneously with the alkylation of said isoparaffin by a second, different monoolefin havinf from 3 to 8 carbon atoms, wherein the mole ratio of first monoolefin to second monoolefin is at least 5:1.
2. The process according to claim 1 wherein the first monoolefin is admixed with normal paraffins having from 2 to 4 carbon atoms.
3. The process according to claim 1 wherein the second monoolefin is butene-l.
4. The process according to claim 1 wherein the second monoolefin is butene-Z.
5. The process according to claim 1 wherein the second monoolefin is 2-methylbutene-2.
6. The process according to claim 1 wherein the second monoolefin is isobutylene.
7. The process according to claim 1 wherein the second monoolefin is a mixture comprising butene-l, butene-2 and isobutylene.
8. The process according to claim 1 wherein the second monoolefin is admixed with normal paraffins having from 2 to 4 carbon atoms.
9. The process according to claim 1 wherein the iso paraffin is isobutene.
10. The process according to claim 1 wherein the alkylation is carried out at a temperature of from about -10 to 50C.
11. The process according to claim 1 wherein the reaction is carried out under pressure in the range of about 1 to 1,000 psi.
12. The process according to claim 1 wherein the molar ratio of isoparaffin to first monoolefin is from about 1:1 to :1.
13. The process according to claim 1 wherein the mole ratio of first monoolefin to second monoolefin is in the range of from about 10:1 to 20:1.
14. The process according to claim 1 wherein the ratio of isoparaffin to catalyst is from about 10 to 500 cc to catalyst per 100 cc of isoparaffin.
15. The process according to claim 1 wherein the first monoolefin is ethylene, the isoparaffin is isobutane and the second monoolefin is butene-2.
16. The process according to claim 1 wherein the first monoolefin is ethylene, the isoparaffin is isobutene, and the second monoolefin is a mixture of olefins comprising butene-l, butene-2 and isobutylene.
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|International Classification||C07C2/62, C07C2/00|
|Cooperative Classification||C07C2/62, C07C2527/1213, C07C2527/173|