US3256345A - Alkylation of hydroxyalkyl and aminoakyl substituted aromatic compounds - Google Patents

Description

United States Patent 3,256,345 ALKYLATION 0F HY DROXYALKYL AND AMINO- ALKYL SUBSTITUTED AROMATIC COMPOUNDS Paul W. Solomon, Bartlesville, Okla., assignor to Phillips Petroleum Company, a corporation of Delaware No Drawing. Filed Sept. 28, 1962, Ser. No. 227,062 5 Claims. (Cl. 260-618) This invention relates to the alkylation of aroma-tic compounds. In one aspect this invention relates to the free radial alkyl-ation'of aromatic compounds by l-olefins.

It is well known to produce free radicals by the decomposition of organic peroxides. In my copending application Ser. No. 845,072, filed October 8, 1959, and now US. Patent No. 3,086,982, it is disclosed and claimed that such free radicals are capable of causing the alkylation of side chains of alkyl esters and alkyl ketones using l-olefins as alkylating agents. The invention of said copending application thus provides a new process for the preparation of long chain alkyl esters and long chain alkyl ketones, which process is not limited by the availability of alcohols and acids of correct chain length as are the processes of the prior art.

I have now discovered that the side chain of certain substituted aromatic compounds having a side chain containing at least two adjacent carbon atoms therein which are adjacent the aromatic nucleus can be alkylated by l-olefins containing from 4 to 18 carbon atoms per molecule in the presence of a free radial initiator. Thus, broadly speaking, the present invention resides in alkylating the side chain of certain aromatic compounds (defined hereinafter) having a side chain containing at least two adjacent carbon atoms therein which are adjacent the aromatic nucleus by reacting said aromatic compounds With a l-olefin containing from 4 to 18 carbon atoms under alkylation conditions in the presence of a free radical initiator; and in certain alkylated aromatic compounds produced in accordance with the above alkylation process, and identified hereinafter.

An object of this invention is to provide a process for alkylating aromatic compounds. Another object of this invention is to provide a process for alkylating a side chain attached to the aromatic nucleus of an aromatic compound. Still another object of this invention is to provide new aromatic compounds. Still another object of this invention is to provide a process for increasing the length of a side chain attached to the aromatic nucleus of an aromatic compound, said side chain having at least two adjacent carbon atoms therein which are adjacent said aromatic nucleus. Another object of this invention is to provide a process by which alkyl radicals can be introduced into the side chain attached to the aromatic nucleus of an aromatic compound. Another object of this invention is to provide a process for reacting an aromatic compound with a l-olefin in the presence of a free radical initiator to increase the length of a side chain attached to the aromatic nucleus of said compound, said side chain having at least two adjacent carbon atoms therein which are adjacent said aromatic nucleus. Other aspects, objects, and advantages of the invention will be apparent to those skilled in the art in view of this disclosure.

Thus according to the invention, there is provided an alkylation process which comprises reacting an acryclic 1- olefin containing from 4 to 18 carbon atoms per molecule with an aromatic compound characterized by the formula wherein: n is an integer of from 1 to 7 inclusive; R is selected from the group consisting of a hydrogen atom and hydroxyl, cyano, -N(R') and radicals wherein each R is selected from the group consisting of a hydrogen atom and alkyl and cycloalkyl radicals containing from 1 to 8 carbon atoms inclusive; under alkylating conditions; in the presence of a free radical initiator; and recovering an alkylated aromatic compound from the resulting reaction mixture.

Further according to the invention there are provided new aromatic compounds and compositions including:

1-octyl-2-phenylethylamine; l-heXadecyl-Z-phenylethylamine; l-octyl-2-phenylethanol; 2-octyl-2-phenylethanol; a mixture of l-octyl-Z-phenylethanol and 2-octyl-2-phenylethanol; l-hexadecyl-2-phenylethanol; Z-heXadecyI-Z-phenylethanol; and a mixture of l-hexadecyl-Z-phenylethanol and 2-hexadecyI-Z-phenylethanol.

Not all aromatic compounds can be alkylated in accordance with the process of the invention. It should be particularly noted that the side chain attached to the aromatic nucleus of the aromatic compound must contain at least two adjacent carbon atoms therein which are adjacent said aromatic nucleus. Thus, surprisingly, I have found that such compounds as toluene, aniline, and benzylamine cannot be alkylated in accordance with the process of this invention. When it is attempted to alkylate toluene -as in the process of the present invention there is obtained diphenylethane. When an attempt is made to alkylate aniline or benzylamine in accordance with the process of the invention no reaction occurs.

Examples of aromatic compounds in accordance with the above general formula which can be alkylated in accordance with the invention include, among others, the following: phenylethane, l-phenylpropane, l-phenylbutane, l-phenyl-2,Z-dimethylpropane, 1-phenyl-3-methylpentane,

1-phenyl-3,5-dimethylhexane,

3 N,N-diethyl-4-ethyl-6-phenylcaproamide, N,N-din-octyl-3-phenylpropionamide, N-r nethyl-N-cyclohexyl-4-phenylbutyramide, 8-phenylcaprylarnide, and N,N-di-n-octyl-8-phenylcaprylamide.

The l-olefins which can be used as alkylating agents in accordance with the present invention are acylic l-olefins containing from 4 to 18 carbon atoms. As used herein and in the claims, unless otherwise specified, the term l-olefins includes both normal and branched chain monoolefinic hydrocarbons in which the double bond is in a terminal or l-sposition. Examples of suitable l-olefins which can be used in the practice of the invention in clude, among others, the following: l-butene, isobutene, 3-methyl-l-pentene, 2,4-diethyl-1-hexene, l-octene, 1- nonene, 3,5,8-trimethyl-l-decene, l-dodecene, 4-n-propyll-tetradecene, l-hexadecene and l-octadecene.

As indicated above, the alkylation of the aromatic compounds with l-olefins in accordance with the invention is carried out in the presence of a free radical initiator. Any suitable free radical initiator which decomposes at usable rates under the reaction condiitons to furnish free radicals can be used in the practice of the invention. Suitable initiators for furnishing free radicals include the organic peroxide, hydroperoxide, and azo compounds which have half-lives in the range of 0.05 to 50, preferably 0.05 to 20, hours under reaction conditions. Said suitable free radical initiators generally will contain from 4 to 50 carbon atoms per molecule and usually will contain less than 20 carbon atoms. Representative examples of suitable free radical initiators include, among others, the following: di-tert-butyl peroxide; tert-butyl hydroperoxide; benzoyl peroxide; azobisisobutyronitrile; tert-butylbenzene hydroperoxide; decumyl peroxide; hydroxyheptyl peroxide; cyclohexanone peroxide; t-butylperacetate; 'di-t-butyl diperphthalate; t-butyl perbenzoate; methyl ethyl ketone peroxide; p-menthane hydroperoxide; pinane hydroperoxide; 2,5-dimethylhexane-2,S-dihydroperoxide; cumene hydroperoxide; and the like. The dialkyl peroxides disclosed in my said copending application can also be used in the practice of the invention. Di-tert-butyl peroxide is the presently most preferred free radical initiator.

The process of the invention can be carried out over relatively wide ranges of temperature, pressure, reaction time, etc. depending upon the particular reactants and free radical initiator employed. However, in general, in the practice of the invention the reaction temperature will be within the range of from 30 to 300 C., preferably 100 to 150 C. A reaction temperature should not be chosen which is above the critical temperature of either of the reactants, i.e., aromatic compound or l-olefin.

Since the half-life .of the free radical initiator is temperature sensitive, the reaction time ordinarily varies inversely with the reaction temperature. Said reaction time can vary from 0.1 to 100 hours or more. A range of from 1 to about 50 hours now appears to provide suflicient time for an appreciable reaction to occur. Residual free radical initiator when present during the separation of the reaction products may lead to explosions if in distillation the distillation vessel is taken nearly to dryness. Therefore, in the examples, reaction times of about 48 hours were employed to make certain that the peroxide was completely pyrolyzed.

The decomposition of the .free radical initiator by pyrolysis is not sensitive to pressure. Therefore, essentially the vapor pressure of the reactants constitutes the lower limit on this variable. Inert gas can be used to pressurize the reaction vessel, if desired. The reaction is carried outin liquid phase and sufficient pressure is maintained on the reaction vessel to maintain the reactants in liquid phase. Usually, the pressure will be within the range of from 0.5 to 50- atmospheres, although higher pressures can be employed if desired.

The ratio or amounts of the reactants and the free radical initiator employed can vary appreciably. However,

best results are obtained by using a molar excess of aromatic compound to the l-olefin. The mol ratio of aromatic compound to l-olefin will generally be within the range of from 2 to 20, preferably 5 to 15. The amount of free radical initiator or supplier present will generally be within the range of from 0.5 to 5 mol percent, based on the total mols of aromatic compound and l-olefin present.

Although the reaction mechanisms of the process of the invention has not been fully established, the results obtained are consistent with a free radical chain mechanism.

Numerous variations in operative procedure can be employed. The process of this invention can be carried out as a batch process, for example, by charging the reactants into a reaction vessel containing an initiator. 'Although any suitable charging procedure can be used, the aromatic compound is generally charged first followed by the 1- olefin and free radical initiator. Also, if desired, the present process can be carried out in a continuous manner. Apparatus suitable for carrying out the processes of the invention will be known to those skilled in 'the art. Any suitable apparatus can be employed.

It is desirable to keepthe reaction system as free of chain terminating components as practicable since the reaction appears to be a chain reaction once it is initiated. Such undesirable materials include mercaptans, quinones, and the like. It is highly desirable, therefore, that the feed components or reactants be freed of these materials as well as other materials which may tend to inhibit the reaction. Any of the known means for removing such contaminants can be used. High feed purity with respect to these undesirable chain terminating components produces higher yields of product based on the initiator.

At the completion of the reaction, the total reaction mixture can be subjected to any suitable known separation procedure, e.g., distillation and extraction, for recovering the alkylated aromatic compound product and unreacted reactants that may be present.

The products of this invention are useful as plasticizers, emulsifiers, and the like. The products of this invention are also useful as intermediates for the preparation of plasticizers, emulsifiers, or pest combatting agents such as fungicides. The products of the invention are also useful as intermediates for the preparation of detergents. F or example, ethylbenzene can be alkylated with a l-olefin containing 12 to 14 carbon atoms to increase the length of the side chain on the benzene nucleus and the resultant alkylation product then sulfonated in known manner to produce a detergent.

The following examples will serve to further illustrate the invention. However, saidexamples are included herein for illustrative purposes only and are not to be construed as unduly limiting the invention.

Example I A run was carried out in which 2-phenylethylamine was reacted with l-octene in the presence of a free radical initiator according to the invention.

In this run, 958 grams (7.9 moles) of pre-distilled 2- phenylethylamine (B.P. 199 C.), 143 grams (1.3 moles) of l-octene and 16 grams (0.11 mole) of di-tert-butyl peroxide were charged to a flask, and a stream of prepurified nitrogen was bubbled through the mixture for several minutes to remove the air present. The mixture was then heated to l30 C. and maintained at this temperature for 48 hours. During the reaction period the contents of the flask were stirred by means of a Tefloncoated steel bar and a magnetic stirred. In addition, a slow stream of prepurified nitrogen was bubbled through the mixture throughout the reaction period.

At the end of the 48 hour reaction period, the reaction mixture was allowed to cool to room temperature (approx. 25 C.), after which the mixture was subjected to fractional distillation. The following table summarizes the distillation.

Cut B.P., C. Pressure, Weight,

mm. Hg grams 1 Residue.

Cit

- 6 From the above data Cut C was established to be relatively pure r CaHaCHgCHCaHu.

Cut D was then subjected to analysis as for Cut C. These results are tabulated below.

Cut D Analytical Results Calculated for- 1 Not known. 2 By freezing point depression of benzene.

A l-hexadecyl-Z-phenylethylamine. 4

B =N-isoprop ylidene-l-hexadecyl-2-phenylethylamine.

Based on the weight and boiling point of Cuts A and B, approximately percent of the l-octene reacted.

Cut C from the above distillation was analyzed and its physical properties were also determined.

OUT 0 Physical properties Found Refractive index my 1.5030

Density d6, g./cc. 0.909 Elemetrital Analysis (l-octyl-2-phenylethylamine, weight percen -Ca1culated-- Carbon, 82.4

Hydrogen, 11.6

Nitrogen, 6.0 Found Carbon, 82:3

Hydrogen, 11.

7 Nitrogen, 4.2 (Dumas) 5.2 (by HC104 titration) Calculated Molecular refraction, 75.9 Molecular Weight, 233 Found Molecular refraction, 76.0 Molecular weight, 277, by freezing point depression of benzene.

Benzam-ide, acetamide, and 3,5-dinitrobenzoate derivatives of this cut (Cut C) were then prepared in known manner by reacting portions of said out with benzoyl chloride, acetyl chloride and 3,5-dinitrobenzoic acid, respectively. In each case, a crystalline material formed which was recrystallized from a suitable solvent. In a typical run, 0.01 mole of Cut C, assuming it to be a 1-octyl-Z-phenylethylamine, and 0.01 mole of 3,5-dinitrobenzoic acid were reacted in methanol, following which the methanol was evaporated to obtain a residue. This residue was dissolved in hot benzene, and hexane was added to precipitate the crystals. The crystals, M.P. l33-6 C., were then recovered by filtration.

The derivatives were subjected to elemental analysis and compared to the calculated values for l-octyl-2- phenylethylamine derivatives.

The residue, Cut E, was also subjected to analysis, yielding the following results.

Cut E Calculated For Analytical Results N c 0 H3) 2 [0 1-150 H2C] CazHos 11, 3 =l.537l d4 =0.93l g./cc Molecular weight=780L 769 Weight percent 0 =85. 3. 84. 3 Weight percent H=1l.l 12.1 Weight percent N=3.l 3. 6

1 By freezing point depression of benzene.

Example II For comparative purposes, it was attempted to react l-octene with aniline and withbenzylamine -in the presence of di-tert-butyl peroxide. The charges for each of these runs was as follows.

ercent Carbon Percent Hydrogen Percent Nitrogen Recrystallization Derivative M.P., C. Solvent Calcu- Found Calcu- Found Calcu- Found lated lated lated Aeetamide 96-8 Methanol 78. 5 78. 5 10.6 10.6 5.1 4. 9 Benzamide 117. 5-8. 5 81. 9 81. 8 9. 2 9.9 4. 2 4. 3 3,5-Dinitrobenzoate l336 Benzene/Hexane 62.0 62. 3 7.0 7.3 9. 4 9. 5

7 In each run the reactants were charged to the flask, degassed with nitrogen and heated to 120-125 C. for 100 hours (under nitrogen). The procedure was as described above in the run employing 2-phenyletl1ylamine. When the reaction mixture of each run was distilled, it was apparent that no alkylation occurred in either run.

Example III Another run was carried out in which 2-phenylethanol was reacted with l-octene in the presence of di-tertiary- Found: percent C, 79.3; percent H, 7.6. Calculated for 2,3-diphenyl-1,4-butanediol: percent C, 79.3; percent H, 7.5.

Cut B analyzed to be approximately 70 percent. Z-phenylethanol and the remainder was assumed to be the same as Cut C. Cut D and Cut B (after the solid was removed) were spectrally quite similar to Cut C, the analysis of which is given below. Cut F and Cut H were similar to Cut G, the analysis of which is given below. Cut C was analyzed as follows.

Cut

- Calculated for A and/or B 1 By boiling point elevation of CaH A 1-oetyl-2-phenyl ethanol. B 2-oetyl-2-phenyl ethanol.

butyl peroxide in the same manner as described above in Example I. The results of this run and the analysis of the reaction product are set forth below.

The product was a Water-white liquid which gave the following cuts on fractionation:

The high value for the hydroxyl number indicates that some dextro, levo-racemate of the 2,3-diphenyl-1,4-butanediol (hydroxyl No.463, molecular weight242), identified earlier in Cut E, was present. This would Reagents Used Grams Moles also account for the low carbon and hydrogen values.

A 3,5 -dinitr-obenzoate derivative was prepared and was y m 1.023 separated into two fractions, J and K. J was a solid ti filii rararnj13:31:31:::::::::::::::--:: 12 it it which when recrystallized from ethanol melted at C. K was an 011.

Infrared analysis revealed fractions J and K were both polynitroaromatic esters. analysis gave the following results.

Elemental Found Calculated for 3,5-dinitrobenzoate of (3H J K CtH5CH(C5Hi7) CHzOH 0r CGH5CH2CHCBH17 Percent 64.5 67.9 64.5 Percent H- 6. 7 7. 4 6. 6 Percent N 7. O 5. 6 6. 5

C t B P a C P ht r S The solid derivative, J, confirmed the presence of conu ressuremm' 1g g am siderable 1- or 2-octyl-2-phenylethanol. The oily derivative is not that from 2,3-diphenyl-1,4-butanediol as ele- -219 740 1106 61-133 mental analysis is not in agreement with this. It may 133-135 1 be an impure derivative of the dextro, levo-racemate of 135-148 1 3.5 5:) 148-163 1 5. 4 the 1- or 2-octyl-2-phenylethanol. -163 1 4.8 20mm 01 m 5 Cut G was analyzed as follows.

230 0. 1 7.3 o t G 1 Distilland transferred to difierent fractionation column having 60 Calculated for A and/0r B better fractionation efficiency.

1 Residue. 0 A B Mass and infrared analyses of the low bOlllIlg material Analytical Results gave 946 grams of 2-phenylethanol, 152 grams of OH O H CH0 H l-octene, 16 grams of t-butyl alcohol and traces of ace 6 5 tone and t-butyl peroxide. 65 onncnzonowms 0112011 Based on infrared analysis all the above cuts contained hydroxyl groups. Alkylation took place at both the alpha and beta carbon atoms. The cuts from E to I contained small amounts of carbonyl material.

A few tenths of a gram of a solid separated from Cut E. Said solid was filtered off and recrystallized from 1:1 benzene/cyclohexane to yield long white needles, M.P. 13940 C. The literature reports that meso-2,3- dipheny1-1,4-butaned-iol melts at 137.58.5 C. Elemental analysis confirmed that the solid was the diol.

1 By boiling point elevation of C H A 1-hexadeeyl2-phenylethanol. B 2-heXadeeyl-2-phenylethano1.

No solid derivatives could be prepared on this cut. However, the above data show that this fraction is at least 50 per cent 1- and/or 2-hexadecy'l-2-pheny1ethanol with perhaps some tetracosylphenylethanol present.

1% Infrared spectra of Cut C, Cut D and said liquid E from Cut B indicated that they all had the structure c H OH-R Solid derivatives could not be prepared on any of the fractions obtained in this study. Preparations attempted A molecular weight determination by boiling point ele- 5 included various nitrations, oxidations, and formation of vation of benzene on Cut H gave a value of 538. Since picrates, aroylbenzoic acids, sulfonyl chlorides, sulfoninfrared indicated that this cut was quite similar to Cut G arn1des, and monoand diamines and their acetylated it is probably a mixture of isomeric derivatives;

H Liquid E from Cut 13 CH5CH2$HC4H49 I Analytical Results Literature and Calculated and Values for 2-phenyldecane GHzOH m =1.4892 n,, =1.4s11, aD =1.4s28. CgHs 110241149 d =0.875 gJGG d =0.858 g./cc. B.P.=13s-146 c. (9 m B.P.=144-150 o. (14 mm.). molecular weight 458, and Molar Retraction=72.5 72.1.

Molecular Weight =217 218. OH llgerceng ga n 3.8. ercen l. C H CH2HC 2Ha5 and 1 By freezing point depression of benzene.

GHZOH The physical data above indicate that said liquid E Heap, from Out B is preponderantly a 2-phenyldecane with some molecular weight 570' 2 ,3t-di tphepylaugane 1preisent. Infrared analysis is con- Approximately 20 percent of the original l-octene re- 51S en any 66am acted. 1 OUT 0 Example IV Analytical Results Literature and Calculated Values Another run was carried out in which ethylbenzene was for hwymmdecane reacted with l-octene in the presence of di-tertiary-butyl 4892 2D 1 4793 2 1 t a peroxide in the same manner as described above in EX- 21 13 T E I'IIIIIII phenyn'oc a mane) ample I. The results of this run and analysis of the T 8 Molar Refract1on=l09A 110.0. product are set forth below. Molecular Weight, 1=30 Percent C=86.8 Percent H=l2.2 12.8.

' Reagents Used Grams Moles 1 By freezing point depression of benzene. Ethylbenzene 867 From the above data, a phenyloctadecane 'is definitely %-g lPeroxide 8 indicated and with the help of infrared it can be identi uy 40 fied as a 2-pheny-loctadecane. Infrared analysis is consistent with a mixture of 2-phenyloctade-cane isomers.

CU T D Calculated for- Analytical Results 2-phenyl11exacosane 2,l9 diphenyleic0sane 7LD2D=1.4018- d =0.877 g./cc Molar Refractiou=l46 and 143, resp 149 144 Molecular Weight =395 442 434 Percent C=87.4 86. 8 88. 4 Percent H=l2.0 13.2 11. 6

1 By freezing point depression of benzene.

The product was a water-white liquid which was fractionated as follows: (a plug of t-butyl alcohol which had formed in the condenser of the reaction setup is not included in the products).

Cut B.P., 0. Pressure, Weight, m. Grams CUT A Mass spectrometric analysis of A showed the presence of 827 grams of ethylbenzene and 141 grams of l-octene.

CUT B Out B separated into a liquid, E, and a solid. The solid was recrystallized from ethanol to yield 1.8 grams of white needles, M.P. 1256 C. Based on infrared analysis this solid was meso-2,3-diphenylbutane. Literature melting point for this compound is 126-7 C., confirming its identification.

v prises:

reacting one mol of l-octene with from 2 to 20 mols of an aromatic compound having a side chain attached to a nuclear carbon atom therein, and of the formula 1 l 12 H total mols of said Z-phenylethanol and said l-octene A G H R present; at a temperature which is les than the critj ical temperature of either of said reactants and H within the range of from 100 to 150 C.; under sufrficient pressure to maintain said reactants liquid phase; and recovering said hexadecyl-Z-phenylethan01 from the resulting reaction mixture. wherein,

n is an integer of from 1 to 7 inclusive; References Cit d b th E i R is selected from the group consisting of hydroxyl 10 UNITED STATES PATENTS and NH groups, at a temperature which isless than the critical tem- 2:606:610 11/1953 Efchak 260-668 perature of either of said reactants and within the 5 7 12/1953 l et a1 260-668 X range of from 100 to 150 C.; under a pressure suffi- 217481178 5/1956 Pmes et a1 260658 cient to maintain said reactants in liquid phase; in 15 3105 1,766 8/1962 Hunter et 260-668 the presence of from 0.5 to 5 mol percent, based on 3,082,267 3/1963 Hunter et v 26O668 the total mols of said starting olefin and said starting aromatic compound present, of a free radical initia- FOREIGN PATENTS tor having a ha-lf life within the range of from 0.5 384,314 11/1932 Great Britain. to 50 hours under said reaction conditions; and re- 20 covering from the resulting reaction mixture a OTHER REFERENCES product aromatic compound wherein said side chain K d t t 1,, Chemical Abstracts, vol. 51, pages has been increased in length. 14999 (1957). A FY0958s for Preparing a y -p y Oga-ta, Chemical Abstracts, vol. 13, page 1709 (1919). ethanol, which Process prises: 25 Siegel et al., Jour. Amer. Chem. Soc., vol. 73, pages reacting from 2 to 20 mols of Z-phenylethanol with one 323740 (1951),

mol of l-octene; in the presence of from 0.5 to 5 mol percent of a reaction initiating material consisting CHARLES B. PARKER, Primary Examiner.

essentially of di-tertiary butyl peroxide, based on the ROBERT V HINES Assistant E x aminer

Claims (1)

1. 1-HEXADECYL-2-PHENYLETHAROL.