US3275702A

US3275702A - Alkylation

Info

Publication number: US3275702A
Application number: US302537A
Authority: US
Inventors: Jr Tom Hutson
Original assignee: Phillips Petroleum Co
Current assignee: Phillips Petroleum Co
Priority date: 1963-08-16
Filing date: 1963-08-16
Publication date: 1966-09-27
Anticipated expiration: 1983-09-27

Description

United States Patent 3,275,702 ALKYLATION Tom Hutson, Jr., Bartlesville, Okla., assignor to Phillips Petroleum Company, a corporation of Delaware Filed Aug. 16, 1963, Ser. No. 302,537 4 Claims. (Cl. 260-671) This invention relates to an improved alkylation process. In one aspect, this invention relates to a process for the production of linear detergent base alkylates. In another aspect, this invention relates to the production of high molecular weight detergent alkylates from linear lolefins and aromaic hydrocarbons. In a further aspect, this invention relates to the formation of preferentially substituted detergent alkylates by conducting the alkylation process in a manner which either avoids or substantially reduces the formation of alkylates other than the desired alkylates. In a still further aspect, this invention relates to a method for forming detergent alkylates from l-olefins and benzene in order to preferentially achieve the 2-phenyl alkylates by suppressing double bond shift during the course of the alkylation reaction.

It is well known that aromatic hydrocarbons such as benzene, toluene, naphthalene, and the like may be reacted in the presence of an acid catalyst with a linear l-olefin to produce the corresponding alkylated aromatic hydrocarbons. However, detergent alkylate bases made from linear l-olefins and aromatic hydrocarbons such as benzene using conventional anhydrous hydrofluoric acid catalyst consist of a mixture of aromatic alkanes. Where benzene is used this mixture contains Z-phenyl, 3-phenyl, 4-phenyl, 5-phenyl and 6-pheny1 substitution products and is believed to be the result of double bond shifting prior to alkylation. Such a mixture of phenyl alkanes, when sulfonated and formulated into detergent, produces a detergent of inferior quality as compared with that produced from predominantly Z-phenylalkanes.

It is thus an object of this invention to provide an improved process for the production of linear alkylates,

Another object of this invention is .to provide a process for the preferential formation of 2-substituted aromatic alkanes.

Another object of this invention is to provide an improved process for the production of alkylated benzenes suitable for use as detergent intermediates.

Other objects, aspects and the several advantages of the invention will be apparent to those skilled in the art from a study of the accompanying disclosure, claims and drawmg.

I have now discovered a process for the formation of preferentially substituted alkyl aromatics from aromatic hydrocarbons and linear l-olefins in the presence of HF catalyst wherein the formation of aromatic compounds with substitutents, at positions other than the 2 position is either excluded or substantially reduced. According to the inventive process, by utilizing an HF catalyst containing from 2 to 4, preferably from 2.5 to 3.5, weigh percent of a modifier selected from the group consisting of water and hydrogen, double bond shifting is suppressed prior to or during the alkylation reaction. Thus predominantly the 2-substituted alkylates are produced. In addition to suppressing the double bond shift, I have further discovered that by conducting the alkylation process in a tubular reactor maintained under certain conditions, the 2-position alkylate production is further enhanced. Accordingly, by providing a reactor residence time within the range of 0.1 to 4.5 minutes while maintaining a reaction temperature Within the range of 40 to F. in the reaction zone and sutficient pressure to maintain all the materials in the liquid phase, the detergent alkylate produced is of superior quality and is predominantly a material with the aromatic group in the 2-position of the alkyl chain.

These and other advantages of the present process will be apparent from an explanation of the accompanying drawing, in which is shown a diagrammatic illustration of one specific embodiment of the invention. Specific feed stocks are mentioned in the description, not as limiting the scope of the disclosure but as an aid to clarity in explanation.

Referring to the drawing, an olefin concentrate such as dodecene-l is passed to drier 10 through line 8 and introduced to mixing nozzle 14 through line 12. Here the olefin concentrate is admixed with a molar excess of an aromatic compound, such as benzene, drawn by conduit 16 through drier 18 and through lines 20 and 22. Hydrofluoric acid catalyst is admixed with the mixture by means of nozzle 24, and the resulting mixture is introduced into tubular reactor 26. The feed rates of catalyst, olefin and aromatic compounds are so adjusted as not only to give the desired mol ratios but also to provide a residence time in the tubular reactor 26 within the range of 0.1 to 1.0 minute. Sufficient pressure is maintained to keep the entire mass liquid while the reaction temperature is maintained within the range of 40 to 100 F. Eflluent is discharged from alkylation zone 26 through line 28 to separator 30, where it is divided by gravity into catalyst and hydrocarbon phases. The heavier catalyst phases containing but little catalyst soluble product is recycled through line 32, cooler 34 and line 36 to mixing nozzle 24. Line 38 communicates with line 36 to provide for removal of HF catalyst for regeneration as required. Line 40, communicating with line 36, provides a means for introducing make-up catalyst or modifier into the alkylation system. The total hydrocarbon phase is removed through line 42 to fractionator 44 from which unreacted benzene is removed through line 46 for recycle to the alkylation zone. The remaining eflluent from fractionator 44 is passed through line 48 to fractionator 50 wherein light alkylates boiling within the range of 200 to 450 F. are removed via line 52. The remaining effluent from fractionator 50 is withdrawn through line 54 and passed to fractionator 56, wherein the desired linear detergent alkylate is removed via line 58 and the heavy alkylate boiling above 650 F. is removed through line 60. The linear alkylate thus produced is passed on to subsequent treatment for conversion todetergents or to storage as desired.

Catalyst activity is maintained at a high level by drawing off portions of the used catalyst in line 36 through line 38 and passing it to a catalyst regeneration zone, not shown. The regenerated catalyst, together with such make-up as required, is returned to the system via line 40.

In the accompanying diagrammatical drawing, reference to various pieces of equipment such as pumps, gauges and other equipment which are obviously necessary to actually operate the process have been intentionally omitted. Only suflicient equipment to operate the inventive process has been illustrated, and it is intended that no undue limitation be read into the invention by reference to the drawing and the discussion thereof.

The following example will further serve to illustrate the invention.

3 Example A comparative alkylation of benzene and dodecene-l was carried out under the following conditions:

High Water Convcnin Acid and tional Short Contact Time Test No 1 2 Reactor Stirred Tube Time 4. 0.33 Tempcrature,F 50 50 Pressure, p.s.i.g a 125 126 Benzene/Olefin M01 Ratio. 19. 8 20. 3

HF Acid Data. Wt. percent:

Total Acidi y 92.31 88.73 Soluble Oil 0. 01 0.00 Inorganic Fluori 0.55 0.88 er 0.45 3. 13

Alkylate Analysis:

5 and 6-pheny1-dodecane 48.0 30. 2 4-phcnyl-dodecane 18. O 13. 8 3-phenyl-dodecane 1G. 7 19. 6 2-phenyl-dodecane 17. 3 36. 4 l-phenyl-dodecane O 0 The above data indicate :that by reducing residence time while producing sufficient modifier to prevent double bond shift, a significant reduction is obtained in the various alkylates produced with a corresponding increase in the production of the preferred 2-substituted alkylates.

While the above example has illustrated the present invention by the use of dodecene-l, it is to be understood that other l-olefins having 8 to 18 carbon atoms per molecule are useful in the inventive alkylation process. Likewise, in addition to the illustrated benzene, other suitable aromatic compounds include xylene and the like. In some instances, highly aromatic naphtha fractions, such as can be obtained from thermally cracked naphthas, can be employed as a source of alkylatable aromatic hydrocarbon.

The catalyst employed in the alkylation zone is prefer ably a liquid hydrofluoric acid in concentration of 50 percent or higher. The reaction conditions will generally be in the range of 40 to 100 F. with a pressure suificient to prevent vaporization of the catalyst. For example, a pressure between 25 and 50 p.s.i.g. is sufficient. Flow rates of reactants should be maintained such that a residence time between 0.1 and 4.5 minutes and preferably 0.1 to 1 minute will be provided in the alkylation zone. The mol 4 ratio of aromatic to l-olefin entering to reaction zone should be between 10.1 and 25:1 but preferably about 20:1. The ratio of catalyst employed to total hydrocarbons in the reaction zone should be in the range of about 1:5 to 2:1, but preferably about 1:3 to 1:1.

By the term preferential alkylation as employed herein, there is meant that the alkylate formed by having the modifier included in the catalyst system is predominantly the 2 substituted alkylate. Thus the use of the modifier suppresses alkylation at the other positions available.

Reasonable variations and modifications can be made or followed in view of the foregoing disclosure without departing from the spirit or the scope thereof.

I claim:

1. A process for the preferential alkylation of an aromatic hydrocarbon with an olefinic hydrocarbon in order to achieve predominantly Z-aryl alkanes which comprises introducing said aromatic hydrocarbon and said olefinic hydrocarbon into an alkylation zone at a ratio of about 10:1 to 25 :1 in contact with an HP acid catalyst, said catalyst containing from 2 to 4 weight percent based on total catalyst employed, a modifier selected from the group consisting of hydrogen and water, maintaining the resulting alkylation reaction mixture in said alkylation zone for a time in the range of 0.1 to 4.5 minutes and at a temperature within the range of 40 to 100 F. and thereafter recovering the resulting preferentially formed alkylate as a product of the process.

2. The process of claim 1 wherein said modifier is present in an amount within the range of 2.5 to 3.5 weight percent.

3. The process of claim 1 wherein the reaction mass has a residence time in the alkylation zone in the range of 0.1 to 1.0 minute.

4. A process according to claim 1 wherein said aromatic hydrocarbon is benzene and said olefin hydrocarbon is dodecene-l and the ratio of aromatic hydrocarbon to olefinic hydrocarbon is about 20: 1.

References Cited by the Examiner UNITED STATES PATENTS 2,404,340 7/1946 Zimmerman 260671 2,431,685 12/1947 Cade 260683.51 2,452,812 11/1948 Wachter 260671 X 3,206,524 9/1965 Plaster 2 -671 X DELBERT E. GANTZ, Primary Examiner.

PAUL M. COUGHLAN, Examiner.

C. R. DAVIS, Assistant Examiner.

Claims

1. A PROCESS FOR THE PERFERENTIAL ALKYLATION OF AN AROMATIC HYDROCARBON WITH AN OLEFINIC HYDROCARON IN ORDER TO ACHIEVE PREDOMINANTLY 2-ARYL ALKANES WHICH COMPRISES INTRODUCING SAID AROMATIC HYDROCARBON AND SAID OLEFINIC HYDROCARBON INTO AN ALKYLATION ZONE AT A RATIO OF ABOUT 10:1 TO 25:1 IN CONTACT WITH AN HF ACID CATALYST, SAID CATALYST CONTAINING FROM 2 TO 4 WEIGHT PERCENT BASED ON TOTAL CATALYST EMPLOYED, A MODIIFIER SELECTED FROM THE GROUP CONSISTING OF HYDROGEN AND WATER, MAINTAINING THE RESULTING ALKLYATION REACTION MIXTURE IN SAID ALKYLATION ZONE FOR A TIME IN THE RANGE OF 0.1 TO 4.5 MINUTES AND AT A TEMPERATURE WITHIN THE RANGE OF 40 TO 100*F. AND THEREAFTER RECOVERING THE RESULTING PREFERENTIALLY FORMED ALKYLATE AS A PRODUCT OF THE PROCESS.