US2810769A - Production of long chain alkyl substituted aromatic hydrocarbons - Google Patents

Description

United States Patent PRODUCTION OF LONG CHAIN ALKYL SUB- STITUTED AROMATIC HYDROCARBONS Robert A. Sanford, Park Forest, and Bernard S. Friedman, Chicago, lll., assignors to Sinclair Refining Company, New York, N. Y., a corporation of Maine No Drawing. Application April 1, 1954, Serial No. 420,446

4 Claims. (Cl. 260-671) Our invention relates to the production of long chain alkyl substituted aromatic hydrocarbons which have particular value in the production of oxidation-stable alkyl aromatic acids and detergent compositions. More particularly, our invention relates to the production of such alkyl aromatics in which the alkyl group contains at least 8 carbon atoms by the alkylation of aromatic hydrocarbons with scission-susceptible olefins in the presence of aluminum halide catalysts.

Long chain alkyl aromatic hydrocarbons are conventionally produced by the alkylation of an aromatic hydrocarbon, e. g. benzene, in the presence of an alkylation catalyst such as aluminum chloride. When the alkylation is carried out with a straight chain olefin, the olefin remains intact and the desired long chain alkyl aromatic hydrocarbon is produced with no difliculty. Scissionsusceptible polyolefins, such as diisobutylene, may also be used to react with more reactive aromatic nuclei such as phenol to produce long chain alkyl aromatics. When,- however, the scission-susceptible olefins are reacted with monocyclic aromatic hydrocarbons such as benzene or toluene, the olefin apparently undergoes extensive polymerization and depolymerization or cleavage prior to alkylation and the resulting product is a mixture of alkyl aroma tic hydrocarbons containing new side chains both lower and higher in aliphatic molecular weight than the olefin originally used. This degradation of the olefin also results in the production of substantially inseparable poly-alkylated aromatics of the same molecular weight and boiling range as the desired alkyl aromatic. For example, when benzene is alkylated with diisobutylene under normal alkylation conditions, the olefin appears to undergo depolymerization prior to alkylation and the final product consists mainly of short chain monoand di-tertiary butylated benzene rather than long chain octylated benzene. This is very undesirable, as sulfonation of this mixture produces low yields of sulfonates which are poor in detergent quality and which require costly purification to eliminate or reduce odor, unsulfonated' residue and color bodies. Because of this difiiculty, processes dealing with the production of long chain alkyl aromatics for detergent manufacture by the alkylation of aromatics with an olefin specify that the olefin be substantially free from scission-susceptible olefins such as isobutylene polymers or copolymers.

We have now found that valuable long chain alkyl substituted monocyclic aromatic hydrocarbons in which the alkyl group contains at least 8 carbon atoms are produced in good yields by the alkylation of the aromatic hydrocarbon with scission-susceptible olefins containing at least 8 carbon atoms in the presence of catalysts comprising aluminum halides by controlling the temperature between about -65 to -l C. By controlling the temperature sufiiciently low, cleavage of the olefin is avoided. Thus, toluene is octylated or dodecylated with vdiisobutylene or triisobutylene respectively, or select cleavage-alkylation occurs resulting in the production of alkyl aroma- 2,810,769 Patented Oct. 22, 1957 tics in which the alkyl group contains at least 8 carbon atoms, for example, octylation of toluene with tetraisobutylene. Undesirable clefava ge resulting in the formation of short chain butylated products is substantially avoided and formation of undesirable short chain and polymer products is kept to a According to our invention, a monocyclic aromatic'hydrocarbon is reacted with a scission-susceptible olefin in the presence of a catalyst comprising aluminum halide while controlling the temperature between about 65 to 15 C. At higher temperatures, excessive butylation occurs and at lower temperatures excessive polymerization occurs with little intact alkylation. The reaction is stopped, for example, by quenching with water, the product is washed with Water or alkali solution, dried and the products recovered by distillation.

Generally, the catalyst and aromatic are mixed and then contacted with the olefin. The manner of contacting is important in that abnormal orientation and cleavage reactions may occur with alkylation products while the addition of the olefin to the catalyst and aromatic mixture is being completed. We have found that keeping the olefin concentration low during alkylation and keeping additional contact time after olefin addition to a avoids abnormal orientation and cleavage reactions and results in the production of high yields of the desired alkyl aromatic. Thus, slow addition of the olefin with early quenching of the reaction is preferred procedure. Advantageously, two streams, one containing aromatic hydrocarbon and the olefin and the other aromatic hydrocarbon and catalyst, are directed into a mixing chamber and after a short contact time discharged into a stream of water to stop the reaction. Commercially, a suspended catalyst can be employed and the catalyst separated just before quenching by gravity separation or centrifugation and recycled. The molar ratio of aromatic to olefin to catalyst may vary from about 46:0.5l.5 :0.08-0.3. Preferably, the ratio is 5:l:0.l. n V

By the process of our invention, readily available scission-susceptible olefins can be employed as the olefin source without losses and complications previously encountered in alkylation reactions with aromatic hydrocarbons because of cleavage reactions, to produce, selectively, valuable alkylated aromatics, some of which are novel compounds. The novel compounds produced by our invention are tertiary-alkylated monocyclic aromatic hydrocarbons, i. e. benzene and saturated hydrocarbon substituted benzenes, in which the tertiary-alkyl radical is of a particular type and which contains at least 8 carbon atoms, particularly from 8 to 20 carbon atoms. The tertiary-alkyl radical of our novel compounds is a radical in which all methylene (CHz-,-) or methinyl groups are attached to at least two quaternary carbon atoms.

The novel compounds include, for example, tertiaryalkylated benzencs such as t-dodecyl benzene or 2,2,4,6,6- pentamethyl-4-phenylheptane; tertiary-alkylated toluenes such as t-octyl-toluenes or paraor meta-(1,1,3,3-tetramethylbutyl) toluenes, t-dodecyl-t'olu'enes or 2,2,4,6,6- pentamethyl-4- (paraor meta-tolyl) heptanes, t-hexadecyltoluenes or 2,2,4,6,6, 8,8-heptamethyl-4-(paraor metat'olyl) nonanes; tertiary-alkylated dimethylbeuzenes such as dimethyl-(t-dodecyl)-benzenes or 2,2,4,6,6-pentamethyl-4-(3,4- or 3,5-dimethylphenyl)-heptanes, dimethyl- (thexadecyl)-benzenes or 2,2,4,6,6,8,8-heptamethyl-4 (3,4 or 3,5-dirnethylphenyl)-nonanes; tertiary alkylated octyl toluenes such as di-t-octyl-t-oluene or, di-'(:1,1,3,3- tetramethylbutyl) -toluene;' V and tertiary-alkylated; octyl benzenes' such as 1,4-di (t-octyl )-benzene or 1,4-di

7 least tw'oou'at'ernary carbon atoms (1,1,3,3-tetramethylbutyl)'-benzene. By our invention not only one but two or more of long chain :alkyl groups such as t-octyl, t-dodecyl and t-hexadecyl can be attached m a t c. h r a bq filsa a sr s a i 4 inim; o q vme is roduce "h alkyl aromati s areuse ful s such ori asjchemical alkyl subslituent s to p roduce oxidation-stabletertiary alkylatd triinesic, athniaeq enzon acids useful in greases and,-w;hen es'terified, in plasticizers and resins.

'The s tructure "of the tertiary-allcyl group of our novel com nsate provides advantageous oxidation resistance in that all methyleneor methinyl groups are attached to at For example, the tertiary groups -the tertiary-octyl and tertiar'y-nonyl aromatics of o'u'r invention have the'following structure:

7 C C I V m m G (I -C -+-aromatie V i V who s or 1 o o e V f -d ljO-aromatic (1) I Ihus,' the JQ DQQHY vulnerable position s in the methylene oup of t e e i y-mal d al a P it ss in the methinyl group of the tertiary-nonyl radical ,are protected by the adjacent quaternary groups which effectively preyent .attaclg by oxidative reagents by ivirtue of their bulk,

' n olvin s r c 9 spatia nd ancci contra-st, tertiery-alk l'groups of'terti'ai'yalkylated aromatics in which the group icontains exposed secondary hydrogens"( in methylene groups and exposed tertiary hyrq ep t 1 s?tll r u lr g oup r s i to o i at a a h Fo e am l h fo o n t t ylk lated a omatics a e sub e t to same a ta h lil t la s his t kem mala se i a isobutylene, for example, diisobutylene, triisobutylene and tetraisobutylene, polymers of isoamylene, isohexylene :and isoheptylene as well as eo-polymers of isobutylene with propylene, n-butylene or amylene, and their hydrogen halide adducts. The ease of alkylation Withoutundesirable cleavage varies with the molecular weight of the olefin. Thus, alkylation without undesirable cleavage is more difficult with the hig her molecular weight olefins than with diisobutylene, for example, but such alkylation can be effected. V

By 'monocyclic aromatic hydrocarbons, useful for alkylation according to the process of our invention, we

i mean benzene and saturated hydrocarbon substituted benzenes, i. e. alkyl and cycloalkyl substituted benzenes preferably containingnot'more than 12 carbon atoms in the alkyl or cycloalkyl group. For example, toluene, buty-lbenzene, cyclohexylbenzene, octylbenzene, dimethylbenzene, r( sth lqyclmen )begzeae cl hex t l fi; otyltohieae, a d kmthlwsb e )t uen a e useful subs titiited *benz enes. The easeof allcylationvaries with the type or substitution in the benzene ring, usually decreasing in reactivitytfor example, in the following bvderi i a t lu e b nze e ut benz fie an coi The aromatics are also useful, for example, in the elec- "matics :for sulfonation to producedetergents, wetting agientizind'ernulsifyihg"agents, including synthetic oil- 'soluble sulfonates. addition, nitration and reduction V of these aromaticslyield useful amines-tor surfaetiye agentsand inhibitors; I V 7 I l By scission-susceptible olefins, we means ,olefins, or

their hydrogen'halide 'additioi'products,"containing at -least 8 'carblon atoms which tend, to emerge cleavage undernormal alkyl a'tion conditionsI 'lhe :mostfuseful scission-susc'eptible folefins contain' from 8 to 2 0 carbon benzene. V

By aluminum halide catalysts, we mean aluminum chloride or aluminum bromide, either unpromoted or promoted by the additionof the corresponding hydrogen halide. Aluminum;halide-hydrocarbon complexes such as that formed in the alkylation process, or produced separately :by mixing and/or heating the aluminum halide with extraneous hydrocarbons, may be employed for the alkylation reaction. V V V T In the alkylation, thetemperature required within the range'ot to l5 C. for optimum alkylation minimum undesirable cleavage and polymer formation varies with the catalyst, the'reactivity of the" aromatic and the olefin ,usedi -For' exaniple, inithe presen ce of uupromoted aluminum chloride, optimum octyl ation" of toluene with diisobutylene occurs at about +35 to" 2 0 G. With benzene, however, a less reactive aromatic, optimum octylation occurs at a higher t einperature, i. e.

about -20 to 15- C, In the 1alkylationof benzeng the V benzenejis advantageously dissolvedi n a solvent such as n-pentane orjn heptane to maintain solution, When the hydrogen halide addition product of the olefin is used for alkylation, generallylower temperatures are required. For example, t-dodecylchloride and toluene give high yields of dodecyl-toluene, and t-hexadecyl chloride and are required for optimum alkylation without undesirable cleavage thantwhen using annnp'romote'd catalyst. *rer example, optimum octylation of toluene with diisqbutylene' occurs at about +65? C. in the pres encefof analuminum chloride catalyst promoted with hydrogen chloride.

With benzene, however, such low temperatures arenot ie quired and optimum octylation is obtained with a temperature range of about -40 to -20 C., particularly about -35 C.' The hydrogen -halide addition products of the olefin may-be used itdesiredand require temper 'aturesj A A V a The process of our invention will befurther illustrated by the following examples. 7

N i I Ek ampleI.

A four-necked iluted flask was fitt d with a-V'stirrer,

idrdbpiiigifuimeli e mga s and r fl x s ndenss 1191;1-

' ing a calcium chloride drying tube An isopropanol bath m w th an e a ed i p halide catalysts promoted with a hydrog'en halide are employed, generally lower temperatures peratures. Eleven gramsof aluminum chloride catalyst were added at 30 C. to 460 grams of toluene in the flask and to this stirred mixture were added 112 grams of diisobutylene over a period of 170 minutes while maintaining the temperature at 30 C. Stirring was continued for 60 minutes after addition of the olefin while maintaining the termperature at C. The reaction was stopped by quenching the hydrocarbon layer with water. The alkylation products were washed with water and sodium bicarbonate solution, dried over anhydrous potassium carbonate and fractionally distilled. The distilled products were examined using an infrared spectrophotometer.

The products, based on the Weight percent of olefin converted, were 28.5 percent para-t-octyl and 24.5 meta-- t-octyl toluene, 14.9 percent para-t-dodecyl and 5.9 percent meta-t-dodecyl toluene and only 6.1 percent t-butyl toluene. No polymer was formed.

Example 11 Using the procedure of Example I, the same proportions of aluminum chloride, toluene and diisobutylene were reacted. The catalyst was added at C. and the olefin was added over a period of 30 minutes and stirring was continued for 60 minutes. The reaction temperature was maintained at 34 C. The products, based on the weight percent of olefin converted, were 45.4 percent t-octyl toluene, 25.4 percent t-dodecyl toluene, 23.8 percent para-t-hexadecyl toluene and only 6.5 percent t-butyl toluene. No polymer was formed.

The para-(t-hexadecyl) toluene or 2,2,4,6,6,8,8-heptamethyl-4-(p-tolyl) nonane was examined to determine its physical properties. The compound had a boiling point of 200 C. at 30 mm. and was a gel at room temperature. The refractive index (n 25/ D) was 1.4893 and the specific gravity (d 20/4) was 0.8730.

Example Ill Using the procedure of Example I, the same proportions or aluminum chloride, toluene and diisobutylene were reacted. The catalyst was added at 35 C. and the olefin was added over a period of 34 minutes and stirring was continued for only 6 minutes. The reaction. temperature was maintained at 35 C. The products, based on the weight percent olefin converted were 69.7 percent para-t-octyl and 9.9 percent meta-t-octyl toluene and only 4.7 percent para-t-butyl and 1.3 percent metat-butyl toluene. No polymer was formed. The high yield of t-octyl toluene shows the advantage of slow addition of the olefin with early quenching of the reaction.

The para-(t-octyl) toluene or p-(1,l,3,3-tetramethyl butyl) toluene was examined to determine its physical properties. The compound had a boiling point of 249 C. at 760 mm. and a melting point of l0 C. The refractive index (n 25/D) was 1.4939 and the specific gravity (d 20/4) was 0.8736. A molecular weight of 200, 88.1 percent carbon and 11.8 percent hydrogen were found which closely corresponds to the calculated molecular weight of 204.3, percent carbon of 88.1 and percent hydrogen of 11.9 for the formula CrsHzr.

Example IV Using the procedure of Example I, 11.7 grams of aluminum chloride were added at -20 C. to 460 grams of toluene. 224 grams of tetra-isobutylene were added to the stirred mixture over a period of 60 minutes and stirring was continued for 60 minutes. The reaction temperature was maintained at 35 C. The products, based on the weight percent olefin converted, were 62.5 percent para-t-octyl, 3.9 percent meta-t-octyl and 1.4 per cent octyl toluene, 10.1 percent dodecyl toluene, 16.0 percent para-hexadecyl toluene nad only 4.6 percent t-butyl toluene. No polymer was formed. Thus, select cleavage of the C16 olefin was obtained to produce a good yield of t-octyl toluenes.

Example V Using the procedure of Example I, 11.1 grams or. aluminum chloride were added at 20 C. to 390 grams of benzene in 270 grams of an n-pentane diluent. 112

grams of diisobutylene were added to the stirred mixture Example VI Using the procedure of Example I, 4.8 grams of a.lu minum chloride were added at 20" C. to 154 grams of toluene. 50 grams of t-octyl chloride were added to the stirred mixture over a period of 30 minutes and stirring was continued for 60 minutes. The reaction temperature was maintained at 60 C. The products, based on the weight percent alkyl chloride converted, were 16.9 percent para-t-octyl and 51.1 percent meta-t-octyl toluene and only 11.2 percent t-butyl toluene.

The meta-t-octyl toluene or m-(1,1,3,3-tetramethy1- butyl) toluene was examined to determine its physical properties. The compound had a boiling point of 118 C. at 15 mm. and 242 C. at 760 mm. and was a gel at room temperature. The refractive index (n 25/D) was 1.4937.

Example VII Using the procedure of Example I, 11.5 grams of aluminum chloride were added at 20 C. to 460 grams of toluene and 3 grams of HCl was passed into the mixture. 112 grams of diisobutylene were added to the stirred mixture over a period of 50 minutes and stirring was continued for 40 minutes. The reaction temperature was maintained at 65 C. The products, based on the weight percent olefin converted, were 61.6 percent para-toctyl and 10.9 percent meta-t-octyl toluene, 20.6 percent para-t-dodecyl and 4.1 percent meta-t-dodecyl toluene and only 3.1 percent t-butyl toluene and 2.9 percent polymer.

Example VIII Using the procedure of Example I, 5 grams of aluminum chloride were added at 0 C. to 156 grams of benzene in 120 grams of n-pentane. 81.6 grams of tdodecyl chloride were added to the stirred mixture over a period of minutes and stirring was continued for 30 minutes. The reaction temperature was maintained at 40 C. The products, based on the weight percent olefin converted, were 26.7 percent octyl benzene, 3.5 percent di-tbutyl and 25.3 percent t-dodecyl benzene.

The t-dodecyl benzene or 2,2,4,6,6-pentamethyl-4- phenyl heptane was examined to determine its physical properties. The compound had a boiling point of 297 C. at 760 mm. and was a gel at room temperature. The refractive index (n 25/D) was 1.4921 and the specific gravity (d 20/4) was 0.8693. 87.7 percent carbon and 12.7 percent hydrogen were found which closely agrees with the calculated percent carbon of 87.7 and percent hydrogen of 12.3 for the formula C13H30.

Example IX Using the procedure of Example I, 6 grams of aluminum chloride were added at 45 C. to 39 grams of benzene in 187 grams of an n-pentane diluent. 112 grams of t-octyl chloride were added to the stirred mixture over a period of minutes and stirring was continued for 10 minutes. The reaction temperature was maintained at 45 C. The products, based on the weight percent olefin converted, were 13.4 percent t-octyl benzene, 11.2 percent octyl benzene, 4.4 percent di-t-butyl benzene, 19.4 percent dodecyl benzene, 30.8 percent di-t-octyl benzene and 1.6 percent dioctyl benzene. No butyl benzene was formed.

' The di-t-octyl benzene or;1,4 di-(1,1,3,3-tetramethylbutyl), benzene was examined to determine its physical propjertiesi- The comgeurrdhad a boiling 'point'of 329 'C. at'766 iirirn-.' arid a gel at room temperature. The

' r'fractiye in'deii (n 25713) was 1.4959 and the specific gra ityld 2074)] was 0.8831. A rnolecular weight of 297, 87I1ipe1fentf carbonfland 12.4 percent hydrogen were foundwh'ichlclos'ely agrees, with the calculated molecular weight of 3025, percent carbon of 87.3 and percent hy drogjnofl2r7 for' the formula CzzHss.

f ,fExan tple X 7 Using the procedure of Example 1; 12 grams of aluminum chloride were added at 30 C. to 460 grams of toluene. 168 grams of triisobutylene were added to the stirred mixture over a'period of 30 minutes and stirring was continued for 60 minutes. The reaction temperature was niaifitaified'at' GS C. Theproducts, based on the weightpercent'olefin converted, were 8.0 percent p'ara-tocftylltolun'e, 1.6 percent meta-t-octyl' toluene, 24.3 perclent para-t-dodec'yl toluene .or 2,2,4,6,6-pentamethyl-4- (p-tolyllheptane, 2.0 percent meta-t-dodecyl toluene, 7.9 percent p'ara-hexadecyl toluene, 39L0'percent polymer and only 12.6 percent t-butyl toluene.

' 'We' claim:

I. A process 'for the production of long chain tertiary alkyl substituted monocyclic aromatic hydrocarbons in which the alkyl group contains from 8 to 20 carbon atoms, which comprises reacting a monocyclic aromatic hydrocarbon selected fi omsthe group consisting of; benzeneiand-z toluene.- with. a scission susceptible tertiary olefin, selectedz from the group consistingof polymers'of isobutylenegcon taining from 8' to 20 carbon-atomsand'their hydrogen halide addition productsin the presence of acatalyst 001111-- prising aluminum chloride while controlling the tempera.

* toluene with. a polymer of isobutylene containing from- 8 to 20 carbon atoms in the presence of an aluminum;chlow;v ride catalyst whilev controlling the temperature at about ReferencesCitedin the file of this patent UNITED STATES PATENTS.

2,072,153 Bruson f Mar. 2, 1937' 2,232,117 Kyrides' Feb. 18', 1941. 2,437,356 Hill Mar. 9, 1948' 2,456,119 7 Friedman et al. Dec. 14, 1948' 2,673,224 Kennedy et' a1 Mar. 24, 1954'. 2,768,985

Schlatter Oct. 30, 1956 1

Claims (1)

1. A PROCESS FOR THE PRODUCTION OF LONG CHAIN TERTIARY ALKYL SUBSTITUTED MONOCYCLIC AROMATIC HYDROCARBONS IN WHICH THE ALKYL GROUP CONTAINS FROM 8 TO 20 CARBON ATOMS, WHICH COMPRISES REACTING A MONOCYCLIC AROMATIC HYDROCARBON SELECTED FROM THE GROUP CONSISTING OF BENZENE AND TOLUENE WITH A SCISSION-SUSCEPTIBLE TERTIARY OLEFIN SELECTED FROM THE GROUP CONSISTING OF POLYMERS OF ISOBUTYLENE CONTAINING FROM 8 TO 20 CARBON ATOMS AND THEIR HYDROGEN HALIDE ADDITION PRODUCTS IN THE PRESENCE OF A CATALYST COMPRISING ALUMINUM CHLORIDE WHILE CONTROLLING THR TEMPERATURE AT ABOUT -65* TO -15*C.