US3909432A - Preparation of synthetic hydrocarbon lubricants - Google Patents

Abstract

This disclosure concerns a process for preparing a synthetic hydrocarbon lubricant composition, said composition consisting essentially of a major amount of di-long-chain alkyl monocyclic aromatic hydrocarbons and a minor amount of trialkyl-substituted tetrahydronaphthalenes. The process comprises (a) alkylating an admixture of a major amount of mono-long chain alkyl monocyclic aromatic hydrocarbons and a minor amount of alkyl-substituted tetrahydronaphthalenes with linear mono-olefins containing six to 18 carbon atoms, using aluminum chloride or aluminum bromide as the catalyst, under severe reaction conditions and (b) recovering the desired product. In both the mono-long-chain alkyl aromatic and di-long-chain alkyl aromatic hydrocarbons, the long-chain alkyl groups are linear and contain six to 18 carbon atoms while the aromatic moiety is phenyl, tolyl, or xylyl.

Description

United States Patent McGuire et al.

[63] Continuation-impart of Ser. No. 417,683. Nov. 26,

I974, abandoned.

[52] US. Cl. 252/59; 260/671 G [51] Int. Cl.'-'. ClOM 1/16; ClOM 3/lO; ClOM 5/08; ClOM 7/12 [58] Field of Search 252/59; 260/671 G [56] References Cited UNITED STATES PATENTS 3.775.325 ll/l973 Kerfoot et al 252/59 5/l974 Krenowicz et al. 252/59 PREPARATION OF SYNTHETIC HYDROCARBON LUBRICANTS Inventors: Stephen E. McGuire; John L.

Riddle; Gene E. Nicks; Oliver Carl Kerfoot, all of Ponca City, Okla; Carl D. Kennedy, Spartanburg, S.C.

Assignee: Continental Oil Company, Ponca City, Okla.

Filed: July 15, 1974 Appl. No.: 488,622

Related U.S. Application Data Primary E.\'aminerDelbert E. Gantz Assistant E.\'aminerl. Vaughn Attorney, Agent, or FirmBayless E. Rutherford, Jr.

[ 5 7 ABSTRACT This disclosure concerns a process for preparing a synthetic hydrocarbon lubricant composition, said composition consisting essentially of a major amount of di-longchain alkyl monocyclic aromatic hydrocarbons and a minor amount of trialkyl-substituted tetrahydronaphthalenes. The process comprises (a) alkylating an admixture of a major amount of mono-long chain alkyl monocyclic aromatic hydrocarbons and a minor amount of alkyl-substituted tetrahydronaphthalenes with linear mono-olefins containing six to 18 carbon atoms, using aluminum chloride or aluminum bromide as the catalyst, under severe reaction conditions and (b) recovering the desired product. In both the monolong-chain alkyl aromatic and di-long-chain alkyl aromatic hydrocarbons, the long-chain alkyl groups are linear and contain six to 18 carbon atoms while the aromatic moiety is phenyl, tolyl, or xylyl.

18 Claims, No Drawings PREPARATION OF SYNTHETIC HYDROCARBON LUBRICANTS CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a continuation-in-part of Application Serial No. 417,683, filed November 26, 1974 and now abandoned. I

BACKGROUND AND FIELD OF INVENTION This invention is concerned with the preparation of a synthetic hydrocarbon lubricant composition having physical properties which render it particularly useful under low temperatures (-40F or lower).

Heretofore, various synthetic lubricants have been developed to improve upon petroleum-derived lubricants. For example, US. Pat. No. 3,173,965 discloses dialkylbenzenes having properties rendering them useful as lubricants while US. Pat. No. 3,288,176 discloses a bottoms fraction derived from the condensation of a substantially straight chain paraffinic hydrocarbon with an aromatic hydrocarbon as being useful as a lubricant. Among the advantages of synthetic lubricants, in general, are improved viscosity and pour point properties.

Recently, it has been found that the pour point properties of dialkylbenzenes can be improved by incorporating therein additional quantitiesof higher alkylsubstituted tetrahydronaphthalenes, preferably higher trialkyl-substituted tetrahydronaphthalenes, as indicated in US. Pat. No. 3,598,739 to Sias. Such compositions, according to Sias, are formed by separately preparing the higher alkyl-substituted tetrahydronaphthalenes and then physically blending them with the previously prepared dialkylbenzenes sufficient to bring the total content of higher alkyl-substituted tetrahydronaphthalenes in the blend to a level whereby the improved pour point properties are achieved. Thus, while the composition blends have highly desirable properties, the technique by which they are formed suffers from the disadvantage of requiring separate preparation of the higher alkyl-substituted tetrahydronaphthalenes which can be blended with the dialkylbenzenes to attain necessary levels of the tetrahydronaphthalene derivatives in the final composition blend.

Commonly assigned copending application Ser. No. 258,137, filed May 30, 1972, and now US. Pat. No. 3,775,325, discloses a process for preparing compositions of the general type disclosed in Sias. Briefly, the process of the copending application comprises alkylating a mixture of monoalkyl aromatic hydrocarbons and alkyl-substituted tetrahydronaphthalenes with a chlorinated C -C linear hydrocarbon or a fraction containing such.

Our invention is an improvement 'over that of US. Pat. No. 3,775,325. We have found that use of linear mono-olefins as the alkylating agent provides several advantages. In general, the 40F viscosities are better.

More specifically, the -40F viscosities using linear mono-olefins, as compared to chlorinated paraffins, are from about 1,000 to 3,000 centistokes better (i.e., lower). An improvement of 1,00'0 cs at 40F i's quite significant since the addition of additives to produce a compounded lubricant (e.g., a crankcase oil) usually results in 40F viscosity of the product being about twice that of the base oil. Moreover, our process is more attractive economically because of better selectivity to dialkylbenzenes and lower production of undesirable branched paraffin by-products.

PRIOR ART While there is other prior art concerning synthetic hydrocarbon lubricants, to our knowledge none of it is more pertinent than that discussed in the immediate foregoing.

BRIEF SUMMARY OF THE INVENTION Broadly stated, thepresent invention is directed to a process for preparing a synthetic hydrocarbon lubricantcomposition, said composition consisting essentially of dilong-chain alkyl aromatic hydrocarbons, wherein the longchain alkyl groups are linear and contain six to about 18 carbon atoms, with the total number of carbon atoms in the alkyl groups being from 12 to 36, preferably from 20 to 28, and wherein the aromatic 'moiety is phenyl, tolyl, or xylyl and trialkylsubstituted tetrahydronaphthalenes, containing a total of about 18 to about 42 carbons, said process comprisa. alkylating an alkylatable hydrocarbon feedstock comprising a mixtureof mono-long-chain alkyl aromatic hydrocarbons, wherein the long-chain alkyl group and the aromatic moiety correspond to that of the di-long-chain alkyl aromatic'hydrocarbons, and alkyl-substituted tetrahydronaphthalenes containing from 12 to 24 total carbon atoms, with linear monoolefins containing six to 18 carbon atoms, using aluminum chloride or aluminum bromide as the catalyst, under severe reaction conditions, and

b. recovering the desired product by means such as fractional distillation.

The process results in (1) selective alkylation of the alkyl-substituted tetrahydronaphthalenes over the monoalkaryls and (2) avproduct having improved properties. The'process also serves to increase the meta to para ratio of the dialkyl aromatic hydrocarbons produced.

DETAILED DESCRIPTION A Materials Used The alkylatable hydrocarbon feedstock has two essential components: (a) mono-long-chain alkyl aromatics and (b) alkyl-substituted tetrahydronaphthalenes containing 12 to 24 total carbon atoms.

Suitable mono-long-chain alkyl aromatic hydrocarbons are represented by the formula Ar-R wherein Ar is benzene, toluene, or xylene, but preferably is benzene, and wherein R is a linear long-chain alkyl group containing from about six to about 18 carbon atoms, preferably from about 10 to about 14 carbon atoms, and most preferably from about 12 to about 14 carbon atoms. Usually the alkyl group is attached to the aromatic nucleus through a secondary carbon PERCENT BY WEIGHT Suitable Preferred Mono-Long-Chain Alkyl Aromatic Hydrocarbons 60-96 85-96 Alkyl-Substituted Tetrahydronaphthalenes 2-30 2-10 Miscellaneous Alkyl Aromatic Compounds, Less Than 10 5 Suitable linear mono-olefins for use in our process contain from about six to about 18 carbon atoms, preferably from about to about 14 carbon atoms. The double bond in the linear mono-olefins can be present in the a-position or can be randomly located in an internal position. Either pure materials or mixtures of materials containing the designated number of carbon atoms can be used. The preparation of C C a-olefins and C C internal mono-olefins is well known. The a-olefins are particularly suitable for use in our process. The a-olefins which can be used are predominantly linear material but can contain minor amounts (e.g., 2 to about 15 weight percent) of branched chain a-olefins. The branched chain a-olefins appear to deteriorate the physical properties of the product. In addition, it should be mentioned that the linear mono-olefin alkylating agent can contain paraffins of the same approximate molecular weight, which can be separated from the alkylation product by distillation.

Suitable catalysts for use in our process include aluminum chloride, aluminum bromide, and mixtures thereof. Aluminum chloride is preferred because of relative cost.

It is well known in the alkylation art that use of aluminum chloride or aluminum bromide as the catalyst requires the use of a hydrogen-donor promoter, such as water or hydrogen chloride. In many instances, sufficient water is present in situ in the materials used. The type and amount of promoter can be determined readily without undue experimentation by any person skilled in this art.

Process Conditions The relative amounts of linear mono-olefin and alkylatable hydrocarbon feedstocks are as follows:

MOLES OLEFlN/MOLES AROMATIC FEEDSTOCK Suitable Preferred 1:l-l:l0 122-115 An important feature of our process is the use of severe reaction conditions. This can be accomplished by increasing the amount of catalyst or by use of higher temperatures; preferably, both features are used.

Expressed as amount of aluminum chloride or aluminum bromide per unit amount of linear mono-olefin, a suitable amount of aluminum chloride or aluminum bromide is from about 2 to about 10 weight percent, preferably from about 3 to about 6 weight percent.

Preferably, the reaction is conducted using a temper ature in the range of about to about C. A temperature as high as C can be used satisfactorily. Use of a lower temperature (e.g., to 50C) is much less desirable because of the inferior low temperature physical properties of the product, particularly at comparable catalyst levels.

Knowing that the reaction is conducted under severe conditions. and knowing the amounts of catalyst and the reaction temperature range, as described in the foregoing, any person skilled in this art can determine the required reaction time. Suitable reaction times are in the range of about 5 to about 360 minutes, preferably about 15 to about 90 minutes.

Upon completion of the required time of reaction, the reaction is terminated. The alklyation reaction product is introduced into a suitable separator where the catalyst sludge is removed. The catalyst-free alkylation product is then treated to remove residual acidic components and impurities. This can be readily accomplished by washing with water and/or a caustic solution or by percolating the alkylate through a bed of bauxite. Methods of purifying the crude alkylation reaction product are well known in the art.

After the alkylate reaction product has been treated in the manner described, it is then subjected to a fractional distillation in order to obtain the desired product, which is the bottoms fraction.

The cut point for separating the desired bottoms fraction is determined by the molecular weight of the starting materials and by the physical properties desired in the bottoms fraction. In the preferred product, we have found out points of about C to about 220C at 5 mm Hg can be used. In the most preferred product, a cut point of about -l90C at 5 mm Hg is used.

The Product of Our Invention The product of our invention has two essential components: (a) dialkyl aromatic hydrocarbons and (b) trialkyl-substituted tetrahydronaphthalenes.

The dialkyl aromatic hydrocarbons are represented by the formula wherein Ar is benzene, toluene, or xylene and wherein R is a linear alkyl group containing from about six to about 18 carbon atoms, preferably about 10 to about 14 carbon atoms, with the sum of the carbon atoms in these alkyl groups being from about 12 to about 36, preferably from about 20 to about 28.

The trialkyl-substituted tetrahydronaphthalenes can be represented by the formula R EXAMPLES 1-7 These examples show a series of runs wherein the temperature and amount of catalyst were varied. Ex- Rv amples 1-5 used an admixture of monoalkylbenzenes 5 (MAB) and alkyl-substituted tetrahydronaphthalenes (ATHN) having the following composition:

R2 MAB, 91* 95.8 ATHN, "/1 3.6

The MAB contained 53 percent C and 27 percent wherein R is a linear alkyl group containing from about C alkyl groups, with the remainder being predomisix to 18 carbon atoms and preferably from about 10 nantly C16, C and C alkyl groups. to about 14 carbon atoms and wherein R and R are Examples 6 and 7 used an admixture of monoalkyllinear alkyl groups containing from one to about l3 l5 benzenes (MAB) and alkyl-substituted tetrahydrocarbon atoms each, with the sum of R and R being naphthalenes (ATHN) having the following composifrom about 2 to about 14. tion.

The amounts of the dialkyl aromatic hydrocarbons and trialkyl-substituted tetrahydronaphthalenes in the M AB 96 6 product are as follows: ATHN, 3.0

S I b] P f d The MAB contained 42.6 percent C and 36.6 perd C re em cent C no C with the remainder being predomi- DiLnng-Chain Alkyl nantly C C and C f 75-95 The linear mono-olefins used were a mixture of C Tr1alkyl-Subst1tuted Tetrahydronaphthalenes 54() 5-25 C12, C13, and C14 a'olefins- All examples used a mole ratio of monoalkylbenzene mixture to a-olefins of 4:1. The catalyst used in all ex- The product of our invention usually hasa-40F visamples was A c Two i h percent f y of 15,000 or lower- Preferably, the 4OOF 3O moter, based on AlCl was used in all examples. The cosity is 12,000 cs or lower. More preferably, the time was 0 minutes in all runs Viscosity does not exceed 10,000 Accord The reaction temperature and other variables of the ingly, we can state the following limits for the 40F process are Shown i T l vlscosity of the Product of our mvemlon' The physical properties and composition of the products are shown in Table II. The cut point for obtaining the bottoms product was 220C at 5 mm Hg.

Maximum Viscosity, cs TABLE 1 Suitable 15,000 Preferable 12.000 Example No. l 2 3 4 5 6 7 More Preferable l0,000

a-o16nn, MOI Wt I85 185 177 175 175 181 181 AlCI 1 3 5 4 3 5 2 3 T C 70 70 90 70 70 70 70 In order to dlsclose the nature of the present mvenemp tion still more clearly, the following examples will be (l)Based 0n o1-olefin Table 11 Product Properties Example No. l 2 3 4 5 6 7 Meta/para ratio 0.75 0.99 0.96 0.75 0.98 0.67 0.76 DAB( 1 76.6 78.0 78.3 76.3 77.2 71.6 74.2 'lTHN(2), 12.2 10.9 12.0 11.8 11.3 20.6 l8.4 Pour Point,

F 60 65 65 70 Viscosity Index 118 120 114 115 111 107 Viscosity, cs

40F 10,673 9,623 9,941 9,838 10,634 13,590 9,850 I00F 32.95 30.89 31.47 31.27 32.81 35.56 30.40 210F 5.57 5.39 5.35 5.35 5.47 5.72 5.13

(l )Dialkylhenzenes (2 )Trialkyl-substituted tetrahydronaphthalenes given. It is to be understood that the invention is not to be limited to the specific conditions or details set forth in these examples except insofar as such limitations are specified in the appended claims.

EXAMPLES 8-1 0 This series of examples illustrates the improvement in --40F viscosity of the product prepared by our process using a-olefins as the alkylating agent, as compared to the product of U.S. Pat. No. 3,775,235, prepared by a process using chlorinated linear paraffins as the alkylating agent.

Examples 8 and 9 illustrate our process while Example illustrates the process of US. Pat. No. 3,775,235.

In Examples 8 and 9 the admixtures of MAB and ATHN were the same as in Examples l-5. Also, in these examples the a-olefins (alkylating agent) were the same as in Example 3.

In Example 10 the chlorinated paraffin alkylating agent was a mixture of chlorinated C -C paraffins. The paraffins were 24.5 mole percent chlorinated and contained 4.5 weight percent Cl.

The catalyst in all runs was 3 weight percent AlCl The mole ratio of alkylate to alkylating agent was 4:1 in all runs.

The other conditions are shown in Table III below.

Table III Example No. 8 9 It) Time. min. lSO 60 90 Temp, "C 70 90 80 The physical properties and composition of the products are shown in Table IV. The cut point for obtaining (l)Dialkylbenzencs (2 )Trialkyl-substitutcd telrahydronuphthalenes EXAMPLE I 1 In this example, a linear mono-olefin containing 10-14 carbon atoms and having the double bond randomly located in an internal position is used. The internal linear mono-olefins were prepared by catalytic dehydrogenation of linear C C paraffin. The conditions used are similar to those of Example No. 2. The product has similar properties to those obtained in Example No. 2.

Thus, having described the invention in detail, it will be understood by those skilled in the art that certain variations and modifications may be made without departing from the spirit and scope of the invention as defined herein and in the appended claims.

We claim:

1. A process for preparing a synthetic hydrocarbon lubricant composition, said composition consisting essentially of a major amount of di-long chain alkyl monocyclic aromatic hydrocarbon, wherein the longchain alkyl groups are linear and contain six to about 18 carbon atoms and wherein the aryl moiety is phenyl, tolyl or xylyl, and a minor amount of trialkylsubstituted tetrahydronaphthalenes containing about l8 to about 42 carbon atoms total, said process comprising: (a) alkylating an alkylatable hydrocarbon feedstock comprising a mixture of a major amount of mono-long-chain alkyl monocyclic aromatic hydrocarbons, wherein the long-chain alkyl group and the aromatic moiety correspond to that of the di-long-chain alkyl aromatic hydrocarbons, and a minor amount of alkyl-substituted tetrahydronaphthalenes containing from 12 to 24 carbon atoms, with from about 0.1 to about 1.0 mole of linear mono-olefins, containing about six to about l 8 carbon atoms, per mole of monolong-chain alkyl aromatic hydrocarbons and alkylsubstituted tetrahydronaphthalenes, using as the catalyst from about to about 10 weight percent aluminum chloride or aluminum bromide based on said linear mono-olefins, said alkylation being conducted at a temperature of from 50 to about 100C and for a time in the range of about 5 to about 360 minutes, and (b) recovering the desired product by distillation.

2. The process of claim 1 wherein the alkylatable hydrocarbon feedstock contains about 60 to about 96 weight percent mono-long-chain monocyclic alkyl aromatic hydrocarbons and about 2 to about 30 weight percent alkyl-substituted tetrahydronaphthalenes.

3. The process of claim 2 wherein the catalyst is aluminum chloride.

4. The process of claim 3 wherein the amount of catalyst is about 3 to about 6 weight percent.

5. The process of claim4 wherein the temperature is about to about C.

6. The process of claim 5 wherein the linear monoolefins contain from about 10 to about 14 carbon atoms. j

7. The process of claim 1 wherein the linear monoolefins are a-olefins.

8. The process of claim 6 wherein the linear monoolefins are a-olefiris. 4

9. A process for preparing a synthetic hydrocarbon lubricant composition, said composition consisting essentially of a major amount of di-alkylbenzenes, wherein the alkyl groups are linear and contain from about 10 to about 14 carbon atoms and a minor amount of trialkylsubstituted tetrahydronaphthalenes containing 26 to 34 total carbon atoms, said process comprising: (a) alkylating an alkylatable hydrocarbon feedstock comprising a mixture of a major amount of linear mono-C C alkylbenzenes and a minor amount of alkyl-substituted tetrahydronaphthalenes, containing from 16 to 20 total carbon atoms, with from about 0.1 to about 1.0 mole of linear mono-olefins, containing about 10 to about 14 carbon atoms, per mole of monoalkylbenzenes and alkyl-substituted tetrahydronaphthalenes, using as the catalyst from about 2 to about 10 weight percent, based on said linear monoolefins, aluminum chloride or aluminum bromide, said alkylation being conducted at a temperature of from 70 to about 90C and for a time in the range of about 5 to about 360 minutes, and (b) recovering the desired product by.distillation.

10. The process of claim 9 wherein the alkylatable hydrocarbon feedstock contains about 60 to about 96 weight percent mono-C, C, alkylbenzenes and about 2 to about 30 weight percent alkyl-substituted tetrahydronaphthalenes.

11. The processof claim 10 wherein the catalyst is aluminum chloride.

12. The process of claim 11 wherein the amount of linear mono-olefins is from about 0.2 to about 0.5 catalyst is about 3 to about 6 weight percent. moles per mole of monoalkylbenzenes and alkyl- 13. The process of claim 12 wherein the alkyl groups Substituted tetrahydrOnmahthalenesof said mono-alkylbenzene and said di-alkylbenzenes contain from about 12 to about 14 carbon atoms.

14. The recess of claim 13 wherein the alk latable hydrocarbgn feedstock contains from abouty 85 to 17. The process of claim 13 wherein the linear monoabout 96 weight percent mono-alkylbenzenes and from Olefins are a'olefins' about 2 to about weight percent alkyl substituted 18. The process of claim 15 wherein the linear monotetrahydronaphthalenes. 10 Olefins are 15. The process of claim 14 wherein the amount of 16. The process of claim 9 wherein the linear monoolefins are a-olefins-

Claims (18)

1. A PROCESS FOR PREPARING A SYNTHETIC HYDROCARBON LUBRICANT COMPOSITION, SAID COMPOSITION CONSISTING ESSENTIALLY OF A MAJOR AMOUNT OF DI-LONG CHAIN ALKYL MONOCYCLIC AROMATIC HYDROCARBON, WHEREIN THE LONG-CHAIN ALKYL GROUPS ARE LINEAR AND CONTAIN SIX TO ABOUT 18 CARBON AND WHEREIN THE ARYL MOIETY IS PHENYL, TOLYL OR XYLYL AND A MINORAMOUNT OF TRIALKYLSUBSTITUTED TETRAHYDRONAPHTHALENESS CONTAINING ABOUT 18 TO ABOUT 42 CARBON ATONS TOTAL, SAID PROCESS COMPRISING: (A) ALKYLATING AN ALKYALATABLE HYDROCARBON FEEDSTOCK COMPRISING A MIXTURE OF A MAJOR AMOUNT OF MONO-LONG-CHAIN ALKYL MONOCYCLIC AROMATIC HYDROCARBONS, WHEREIN THE LONG-CHAIN ALKYL GROUP AND THE AROMATIC MOIETY CORRESPOND TO THAT OF THE DILONG-CHAN ALKYL AROMATIC HYDROCARBONS, AND A MINOR AMOUNT OF ALKYL-SUBSITIUTED TETRAHYDRONAPHTHALENES CONTAINING FROM 12 TO 24 CARBON ATOMS, WITH ABOUT 0.1 TO ABOUT 1.0 MOLE OF LINEAR MONO-OLEFINS, CONTAINING ABOUT SIX TO ABOUT 18 CARBON ATOMS, PER MOLE OF MONO-LONG-CHAIN ALKYL AROMATIC HYDROCARBONS AND ALKYL-SUBSTITUTED TETRAHYDRONAPHALENES, USING AS THE CATALYST FROM ABOUT 2 TO ABOUT 10 WEIGHT PERCNET ALUMINUM CHLORIDE OR ALUMINUM BROMIDE BASED ON SAID LINEAR MONO-OLEFINS, SAID ALKYLATION BEING CONDUCTED AT A TEMPERATURN OF FROM 50* TO ABOUT 100*C AND FOR A TIME IN THE RANGE OF ABOUT 5 TO ABOUT 360 MINUTES, AND (B) RECOVERIN THE DESIRED PRODUCT BY DISTILLATION.

2. The process of claim 1 wherein the alkylatable hydrocarbon feedstock contains about 60 to about 96 weight percent mono-long-chain monocyclic alkyl aromatic hydrocarbons and about 2 to about 30 weight percent alkyl-substituted tetrahydronaphthalenes.

3. The process of claim 2 wherein the catalyst is aluminum chloride.

4. The process of claim 3 wherein the amount of catalyst is about 3 to about 6 weight percent.

5. The process of claim 4 wherein the temperature is about 70* to about 90*C.

6. The process of claim 5 wherein the linear mono-olefins contain from about 10 to about 14 carbon atoms.

7. The process of claim 1 wherein the linear mono-olefins are Alpha -olefins.

8. The process of claim 6 wherein the linear mono-olefins are Alpha -olefins.

9. A process for preparing a synthetic hydrocarbon lubricant composition, said composition consisting essentially of a major amount of di-alkylbenzenes, wherein the alkyl groups are linear and contain from about 10 to about 14 carbon atoms and a minor amount of trialkyl-substituted tetrahydronaphthalenes containing 26 to 34 total carbon atoms, said process comprising: (a) alkylating an alkylatable hydrocarbon feedstock comprising a mixture of a major amount of linear mono-C10-C14-alkylbenzenes and a minor amount of alkyl-substituted tetrahydronaphthalenes, containing from 16 to 20 total carbon atoms, with from about 0.1 to about 1.0 mole of linear mono-olefins, containing about 10 to about 14 carbon atoms, per mole of monoalkylbenzenes and alkyl-substituted tetrahydronaphthalenes, using as the catalyst from about 2 to about 10 weight percent, based on said linear mono-olefins, aluminum chloride or aluminum bromide, said alkylation being conducted at a temperature of from 70* to about 90*C and for a time in the range of about 5 to about 360 minutes, and (b) recovering the desired product by distillation.

10. The process of claim 9 wherein the alkylatable hydrocarbon feedstock contains about 60 to about 96 weight percent mono-C10-C14 alkylbenzenes and about 2 to about 30 weight percent alkyl-substituted tetrahydronaphthalenes.

11. The process of claim 10 wherein the catalyst is aluminum chloride.

12. The process of claim 11 wherein the amount of catalyst is about 3 to about 6 weight percent.

13. The process of claim 12 wherein the alkyl groups of said mono-alkylbenzene and said di-alkylbenzenes contain from about 12 to about 14 carbon atoms.

14. The process of claim 13 wherein the alkylatable hydrocarbon feedstock contains from about 85 to about 96 weight percent mono-alkylbenzenes and from about 2 to about 10 weight percent alkyl-substituted tetrahydronaphthalenes.

15. The process of claim 14 wherein the amount of linear mono-olefins is from about 0.2 to about 0.5 moles per mole of monoalkylbenzenes and alkyl-substituted tetrahydronaphthalenes.

16. The process of claim 9 wherein the linear mono-olefins are Alpha -olefins.

17. The process of claim 13 wherein the linear mono-olefins are Alpha -olefins.

18. The process of claim 15 wherein the linear mono-olefins are Alpha -olefins.