United States Patent (19) 11 3,875,249 Nelson (45) * Apr. 1, 1975

54 PREPARATION OF HALOALKYL 2,355,850 8/1944 Dreisbach...... 260/651 HA AROMATIC HYDROCARBONS 2.388,428 i? 1945 Mavity...... 260/448 A 2,631, 172 3/1953 Schmerling. ... 260/651 HA 75 Inventor: Gunner E. Nelson, Baton Rouge, La. 2,794,822 6/1957 Schweitzer...... 260/668 C 303514 4/1962 Kosmin...... 260/671 C 73 Assignee: Ethyl Corporation, Richmond, Va. 309,568 6/1963 Hay et al...... 260/671 C k Notice: The portion of the term of this 3,277, 96 ()f 1966 Winkler...... 260/671 P patent subsequent to Jan. 22, 1991, 33 12,748 4/1967 Johnson...... 260/67 R has been disclaimed. OTHER PUBLICATIONS Filed: Apr. 11, 1973 Schmerling et al., JACS, 79, pp. 2636-2642, May 20, Appl. No.: 349,927 1957. Related U.S. Application Data Division of Ser. No. 123()37, March 1 (), 1971, Pat. Prinary Evanliner-C. Davis No. 3,787,512, which is a continuation-in-part of Ser. No. 8 13.340, April 3, 1969, abandoned, which is a Attorney, Agent, or Firn-Donald L. Johnson; John F. continuation-in-part of Ser. No. 568,779, July 29, Sieberth; Edgar E. Spielman, Jr. 966, abandoned. 52 U.S. C. .. 260/651 HA, 260/651 R, 260/668 C. (57 ABSTRACT 260/671 R Process for alkylating an aromatic hydrocarbon by re (5) Int. Cl...... C07c 25/14 acting a haloalkane with either or an (58) Field of Search. 260/651, 651 HA, 448, 671 R, benzene and conducting the reaction in the presence 260/671 B, 671 C, 671 P. 668 C of an alkylaluminum halide catalyst without deliber ately adding heat to elevate the temperature of the re (56) References Cited action. UNITED STATES PATENTS 2,308,419 lf 1943 Heitz et al...... 260/651 HA 6 Claims, No Drawings 3,875, 249 1 2 PREPARATION OF HALOALKYL AROMATIC HYDROCARBONS DESCRIPTION OF THE PREFERRHEID EMBODIMENTS CROSS-REFERENCE TO RELATED APPLICATION The present invention is drawn to several species of This is a division of application Ser. No. 23,037 filed 5 reactions, four of which utilize an cy, co-diha Mr. (), 1971, how U.S. Pt. No. 3,787.5 2, which is loalkane as one reactant and either benzene or an al a continuation-in-part of application Ser. No. 83,340, kylbenzene as the other reactant. Two species of the filed Apr. 3, 1969, which is a continuation-in-part of reactions which produce, respectively, an ad-haloalkyl application Ser. No. 568,779, filed July 29, 1966, the benzene when benzene is a reactant and a p-alkyl-co latter two of which are now abandoned. haloalkylbenzene when an alkylbenzene is reactant, utilize an organic diluent. Another two species of the BACKGROUND OF THE INVENTION reactions which produce, respectively, an cy.co-dipheny This invention relates to the preparation of aromatic laikane when benzene is a reactant and (Y,co-(p.p'-alkyl hydrocarbons through use of aluminum alkyl halicles as diphenyl) when an alkylbenzene is a reactant, do Friedel-Crafts catalysts. By way of example, this inven not utilize a diluent. Still another two species of the re tion concerns a method for forming an a-haloalkylben actions, which employ a monohaloalkane as one reac Zene or a p-alkyl-co-haloalkylbenzene by reacting an tant and either benzene or an alkylbenzene as the other cy.co-dihaloalkane with, respectively, benzene or an al reactant to produce, respectively, a monoalkylbenzene kylbenzene in the presence of a diluent and an alumi or polyalkylbenzene, also employ a diluent; absence of nunn alkyl halide catalyst. Further, this invention con () the diluent in either of these two reactions to the cerns a method for forming an cy.co-diphenylalkane or formation of other polyalkylbenzenes. The remaining an ox.co( p,p'-alkyldiphenyl)alkane by reacting an species of the reactions are similar to the first four reac o, co-dihalolakane with, respectively, benzene or an al tions with the exception of employing cy,c)-dihaloal kylbenzene in the presence of an aluminum alkyl halide kanes having different or polyhaloalkanes catalyst. In addition, this invention provides a method having more than three halogens which are the same or for forming a monoalkylbenzene or polyalkylbenzene different. All of the reactions employ as a catalyst one or a combination of dialkylaluminum halide and/or al by reacting a monohaloalkane with, respectively, ben kylaluminum dihalide. Zene or an alkyl benzene in the presence of a cliluent Preferred reactions are first, the reaction of 1,2- and an aluminum alkyl halide catalyst, absence of a dil 30 dichloroethane with benzene in the presence of an or uent leads to the formation of other polyalkylbenzenes. ganic diluent and methylaluminum Sesquichloride to Other alkylation reactions contemplated by the present produce g-chloroethylbenzene: second, the reaction of invention will become apparent from the following de 1,2-dichloroethane with in the presence of an scription. organic diluent and methylaluminum sesquichloride to The compounds developed by the process of the 3 5 produce p-methyl-g-chloroethylbenzene; third, the re present invention find use both as scavengers for alkyl action of 1,2-dichloroethane with benzene in the pres antiknock agents (see U.S. Pat. Nos. 1,668,022 ence of methylaluminum sesquichloride to produce and 2,398,281 ) and as pesticides when properly ap 1,2-diphenylethane; fourth, the reaction of 1,2- plied as a spray or dusting powder. dichloroethane with toluene in the presence of me The prior art has been beset with two major problems 40 thylaluminum sesquichloride to produce 1,2-(p,p'- in reactions of the types involved in the present inven methyldiphenyl); fifth, the reaction of methyl tion, namely, yield of the desired products has been chloride with benzene in the presence of me quite low and reaction temperatures have been neces thylaluminum sesquichloride and a diluent to produce sarily quite high, thus increasing the number of undesir toluene; and sixth, the reaction of methyl chloride with able impurities in the product. Prior art reactions have toluene in the presence of methylaluminum sesquichlo been conducted using conventional Friedel-Crafts cat ride and a diluent to produce 1,4-dimethylbenzene. alysts such as, for example, aluminum chloride. Litera The order of stating the reactions above does not indi ture references involving such standard Friedel–Crafts cate an order of preference. atalysts report temperature requirements of 70°C. and The improvement of the present invention flows pri higher. marily from the use in alkylation reactions of alkylalu A purpose of the present invention is to overcome minum halide catalysts, a preferred catalyst being me the above-noted disadvantages of the prior art. More thylaluminum sesquihalide, which is a mixture of dime specifically, a purpose of the present invention is to thylaluminum halide and methylaluminum dihalide. produce high yields of the desired aromatic hydrocar The organoaluminum catalysts employed in this inven bons while conducting the requisite chemical reactions 5 5 tion include compounds having the formula RAIX 1. at economically low temperatures. Further advantages wherein R represents a hydrocarbon selected from the and purposes of the present invention will become ap group consisting of alkyl and aryl radicals, X represents parent in the following description. a selected from the group consisting of chlo rine, and , and in represents an integer SUMMARY OF THE INVENTION 60 not greater than 3. Thus, the invention contemplates The present invention provides a process for alkylat the use of all organoaluminum halides of the type ing an aromatic hydrocarbon by reacting a haloalkane RAIX and RAIX and mixtures of the same (e.g. ses with a compound selected from the group consisting of quihalides). In compounds of the RA1X type, the R benzene and alkylbenzenes comprising conducting the groups may be the same or different, e.g. reaction in the presence of an alkyl-aluminum halide (CH)(CH) Alx. These catalysts cause the above re atalyst and avoiding the deliberate addition of heat to actions to proceed at a relatively fast rate at compara elevate the reaction temperature. tively low temperatures which need not exceed room 3,875,249 3 4 temperatures, and thus, no heating is required in the ent. Typical alkylbenzenes include toluene, ethylben present invention as is generally required as taught by Zene, p-ethylpropylbenzene, propylbenzene, butylben the prior art. Conventional Friedel-Crafts catalysts, Zene, isopropylbenzene, isobutylbenzene and decyl such as aluminum chloride, not only require supplying benzene, with a preferred alkylbenzene being toluene. heat to the reaction but tend to remain in suspension 5 Having thus set forth the present invention, the fol in the reactants thus leading to slow reactions. On the lowing examples are presented as being further descrip other hand, alkylaluminum halide catalysts are readily tive of the present invention, though not as limiting Soluble in the reactants and are conducive to fast reac thereof: tions, good conversions and high yields. The molar ratio of reactants to catalyst may range from about ().05 EXAMPLE I to (). 1 to about 5 to 0.1; preferably it will range from One mol of benzene was reacted with ().2 mol of 1,2- about 0. to 1.0 to about 2 to (). In continuous opera dichloroethane in the presence of 0.1 mol of me tion processes, the catalysts of the present invention thylaluminum sesquichloride and a hexane diluent at may be easily recovered and recycled for continuing 25°C. to produce predominantly g-chloroethylben S. 2. Numerous diluents are suitable for those reactions of the present invention which require a diluent. Typical EXAMPLE II organic diluents are ligroin, nitrobenzene, disul One mole of benzene was reacted with ().5 mol of fide, hexane, and isooctane. In general, all paraffinic 1,2-dichloroethane in the presence of 0.2 mol of me hydrocarbons which are liquid at reaction temperature thylaluminum sesquichloride at 25°C. to produce a 80 are suitable. All useful diluents must be liquid at reac percent yield of 1,2-diphenylethane. tion temperatures and inert to the reactants of the pres ent invention. Generally, 50 percent to 8 () percent by EXAMPLE III volume of the reactant solution is diluent. One mol of toluene was reacted with ().2 mol of 1,2- A broad range of monohaloalkanes are useful in 5 dichloroethane in the presence of 0.1 mol of me Some of the reactions of the invention. Exemplary are thylaluminum sesquichloride and a hexane diluent at compounds having up to about 20 carbon atoms, e.g., 25°C. to produce predominantly p-methyl-6-chloroeth methyl chloride, methyl , ethyl chloride, pro ylbenzene. pyl bromide, butyl chloride, pentyl bromide, decyl bro EXAMPLE IV mide, 6-methyl-1-chlorodecane, and the like. Preferred 30 haloalkanes have from 2 up to about 4 carbon atoms. One mol of toluene was reacted with 0.5 mol of 1,2- A comparatively wide variety of cy, co-dihaloalkane re dichloroethane in the presence of 0.2 mol of me actants may be used in some of the present invention. thylaluminum sesquichloride at 25°C. to produce pre Typical a,c-dihaloalkanes have from 2 up to about 20 dominantly 1,2-(p,p'-methyldiphenyl)ethane. carbon atoms and include such compounds as 1,2- 35 The following examples may be carried out under the dichloroethane, 1,2-dibromoethane, 1,2-diiodoethane, listed conditions to yield predominantly the product 1,2-dichloropropane, 1,4-dichlorobutane, and noted. 1,2-dichloro-2-methylpropane, 1,5-dichloropentane, I claim: l,8-dibromooctane, l, l ()-dichlorodecane, 1. A process for producing co-haloalkyl benzene or l, 10-dibromo-6-ethyldecane, and the like. Preferred 40 p-alkyl-a-haloalkyl benzene by reacting o-co-dihaloal o,a)-dihaloalkanes have from about 2 up to about 4 car kane with, respectively, benzene or alkyl benzene in bon atoms, with the most preferred a,co-dihaloalkane the presence of a diluent and alkylaluminum halide cat being 2-dichloroethane. alyst whereby the addition of heat to the reaction is not Polyhaloalkanes other than ov,co-dihaloalkanes having necessary to effect a high reaction rate. two or more halogens which may be the same or differ 2. The process of claim 1 wherein the diluent is a par ent are also useful in the practice of the invention. Such affinic hydrocarbon which is liquid at reaction temper haloalkanes preferably have from 1 up to about 20 car atuCS. bons and preferably up to about 4 carbon atoms. Exem 3. The process of claim 1 wherein the o-o-dihaloal plary are , bromoform, methylene chloride, kane is 1,2-dichloroethane. methyl chloroform, 1,1,2-trichloroethane, 1,1,2,2- 4. The process of claim 1 wherein the alkylaluminum tetraiodoethane, l, l, 1,2-tetrabromoethane, 1,1,3- halide catalyst is methylaluminum sesquichloride. trichloropropane, l, 1,4-triiodobutane, l, 1, 10 5. The process of claim 1 wherein the alkylbenzene trichlorodecanc, chlorobromoethane, l-chloro-3- is toluene. bromo-6-iodohexane, and the like. 6. The process of claim 1 wherein the diluent is a par The present invention also lends itself to a relatively 5 5 affinic hydrocarbon which is liquid at reaction temper wide variety of alkylbenzene reactants having from 7 atures, the ov-co-dihaloalkane is l,2-dichloroethane, the up to about 30 carbon atoms and preferably up to alkylaluminum halide catalyst is methylaluminum ses about 10 carbon atoms; such reactants may include one quichloride and the alkyl benzene is toluene. or several alkyl radicals which are the same or differ 22 k c : 60