US3234297A

US3234297A - Alkyl aryl sulfonate detergents

Info

Publication number: US3234297A
Authority: US
Publication date: 1966-02-08
Anticipated expiration: 1983-02-08

Description

United States Patent 3,234,297 ALKYL ARYL SULFONATE DETERGENTS Charles A. Cohen, Westfield, N.J., assignor to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Filed Mar. 28, 1960, Ser. No. 17,796

The portion of the term of the patent subsequent to Dec. 25, 1980, has been disclaimed 1 Claim. (Cl. 260-668) This invention is concerned with new alkyl benzene hydrocanbons which are useful in the production of superior synthetic detergents, and vw'th the preparation of these hydrocarbons. More particularly, this invention is concerned with the production of alkyl benzene hydrocarbons having at least one nuclear substituted alkyl chain containing from 8 to 24 carbon atoms, said alkyl chain having the structure of a methylene group attached between the benzene nucleus and a highly branched alkyl group. Most particularly this invention relates to a mono alkyl benzene hydrocarbon of the above described structure.

Illustratedin chemical notation, the new alkyl benzene hydrocarbons of this invention may be represented by the following general formula: RCH R wherein R is benzene and R is a branched, acyclic hydrocarbon group of from 10 to 18 carbon atoms. The degree of branching of R is such that about 50 to 95%, preferably 50 to 80%, of the total carbon atoms in the alkyl group (including the methylene group) are in a straight chain of carbon atoms.

The alkali metal sulfonate salts of these alkyl benzene hydrocarbons have now been found to be highly superior to other similar type detergents known in the prior art. This is true not only with respect to the washing properties of these detergents but also with respect to their capacity to be removed in conventional sewage disposal plants. This the present detergents have been found to be substantially entirely absent from the eflluent from such a sewage treatment, having been removed by biodegradation, adsorption, and the like. This property is an extremely important factor in preventing the foaming which has been encountered in rivers and streams into which the eflluent from sewage disposal plants is discharged. It should be noted that it is surprising that both of these improvements are obtained at the same time by utilizing the present easily and cheaply prepared materials having molecular structures as above described.

The present invention will be more clearly understood from a consideration of prior art commercial detergent materials made by alkylating benzene with polymers of propylene containing from 10 to carbon atoms. These prior art detergent materials are the major ones used in the household detengents marketed today. These materials may be represented by the following chemical formula:

R1 b-R. it

3,234,297 Patented Feb. 8, 1966 sist predominantly of tri and tetra alkyl substituted ethylene Thus, the alkyl aromatics obtained on alkylating benzene with this material possess in large part a trialkyl substituted carbon atom adjacent and attached to the aromatic nucleus, i.e.

l. wherein R R and R are alkyl groups.

It is now known that these conventional commercial alkyl benzene sul-fonates having a trialkyl substituted carbon atom attached to the aromatic ring are particularly resistant to biological degradation by bacteria normally present in microorganism populations of activated sewage sludge (and that they are not otherwise removed by adsorption, etc). Further it is known that severe foaming and frothing have occurred in many locations Where sewage disposal plants discharge their efiluent into rivers and streams. It has now been found that the deter: gent material of the type described in this invention is readily degraded bio-logically or is otherwise removed by the microorganisms normally present in this sludge and when processed in a sewage plant produces an etiluent from said plant having little or no tendency to foam.

The presence of, and the relative proportion of alkylatcd aromatics having a tri substituted carbon atom attached to the ring may be estimated by means of mass spectroscopy, nuclear magnetic resonance or infrared spectroscopy. One means, that of mass spectroscopy, for estimating the presence and relative amount of ring-substituted quaternary carbon in an alkylated benzene is by determining the ratio of the amount of mass 91 fragments CH (representing a methylene attached to the ring) to mass 119 fragments with R and R each being a methyl group). For a large number of commercial alkylates, made by the alkylation of benzene wit-h tetrapropylene, this ratio is in'the order of 3.3 while in comparison, pure l-phenyl dodecane gives a ratio of nearly zero. A pure synthetic sample of 2- phenyl-Z-methyl undecane.

gave a ratio of 5.33. Another method for determining the nature and degree of branching on the carbon atom attached to the aromatic ring is by the use of nuclear magnetic resonance. By this means, pure alkylates consisting of l-zphenyl dodccane give values of about 2.2 hydrogen on the carbon adjacent to the ring (theory=2); 2, 3 or 4 phenyl dodecane gives values of about 1.25 hydrogen on the carbon adjacent to the ring (theory=1), and an alkylate made from commercial tetrapropylene shows 0.25 hydrogen on the same carbon (theory for a quaternary carb0n=0.0). Deviations from theory are probably due to calibration errors.

It has now also been discovered that superior washing properties-may be obtained by utilizing a molecular structure wherein 2. CH group links the benzene ring to a branched alkyl material having 50 to 95% of the 3 total carbon atoms in the longest straight chain of the alkyl group measured from said methylene group. Althoughv it is not intended to limit this invention by a particular theory, this improvement in Washing properties may be attributed to changing the molecular volume of the molecule by obtaining a proper balance in the length of the longest alkyl chain measured 'from its point of attachment to the methylene group. It should be noted that this object isnot attained merely by utilizing a higher olefin such as pent'apropylene or a higher fraction obtained from tetra'pr'opyle'ne as the alkylation feed as has been used in some commercial detergents. These detergents although superior in washing properties to conventional tetrapropylene obtained materials are still greatly inferior to the present invention detergents. Thus, it is theorized that just the right balance of solubility and emulsifying properties are obtained in the present product detergent.

A wide variety of methods may be used in preparing the new alkyl aromatics of the present invention. -A preferred method utilizes a highly branched material such as a tetrapropylenefraction of U.O.P. type polymer as the starting material. Olefin polymers suitable for use as feeds'for this process may be obtained from a process as described in US. Patents 2,486,533 and 2,695,326 both of which deal with polymers of C to C normal olefins herein termed U.O.P. type polymers. A fraction of such polymer containing between 9 and 18 carbon atoms to the molecule may be used but a C to C out which is predominantly C is preferred. More specifically the polymers of butene-l and butene-Z and their copolymers with propylene in addition to homopolymers of propylene, e.g. trip'ropylene and tetrapropylene, are preferred. Of these tetrapropylene is most preferred. These materials may be either (a) oxonated to insert a reactive additional carbon atom in the molecule which is then reacted to form the methylene link between the aromatic ring and the alkyl group or '(b) converted to a halide which is then reacted with a material such as ('1) toluene in the presence of an alkali metal or (2) with an alkali metal benzyl material, or a Grignard reagent prepared from a benzyl halide to produce a compound having the desired methylene link "between the aromatic ring and the alkyl group.

The following specific methods of preparation of the desired alkyl benzene hydrocarbons of this invention may be utilized.

(1) A fraction of polymeric U.O.P. olefin as above described, for example, a tetra'propylene or pentapropylene, is subjected to hydroformylation or x0 process to produce an aldehyde having one more carbon atom than the olefin starting material, e.g. tridecyl or hexadecy'l aldehyde. Methods for carrying out this reaction are disclosed for example in US. Patent 2,636,903. 'Thus, in general, temperatures of 150 to-450 C.,e'g. 300 C., pressures of 1500 to 4500 p.s.i.g., e.g. 3000 p.s.i.g., 0.5 to 2.0 molar proportions of .CO to H but preferably equal molar proportions of these materials, and from 0.8 to 2.0 moles, e.g. 1.2 moles, of CO and H per mole of olefin feed-along with 1 to 3 wt. percent of a cobalt catalyst, e.g. cobalt oleate per mole of olefin feed are used. The resulting aldehyde after decobaltingwith steam is reduced to a primary alcohol, also as described in the above'patent, by contacting it with 5,000 to20,000, e.g. 10,000 ft. per bbl. offeed of hydrogen at temperatures of 300 to 500 C., pressures of 2500 to 4500 p.s.i.g. and in the presence of any of the hydrogenation catalysts well known to the art. Suitable catalysts are nickel, copper chromite, cobalt, sulfactive catalysts of the type of oxides and sulfides of tungsten, nickel, molybdenum and the like, either as such or supported on a carrier, e.g. Raney nickel. The alcohol is then converted to a monohalide by contacting it with a halogen acid, e.g. HBr at temperatures of 20 C. to 200 C., e.g. 120 C.,and pressures of l to-2 atmospheres,.e.g. 1 atmosphere. The h ide i then mixed with a monoh lo benzene, e.g.

bromobenzene and is subjected to a Wurtz-Fittig reaction utilizing metallic sodium and temperatures of 20 C. to C., e.g. 35 C. to obtain the alkyl aromatic product. The molar ratios of monohalo benzene to alkyl monohalide for this reaction may be in the range of 0.8 to 1.5, e.g. H0 and the molar ratio of metallic sodium to monohalo benzene may be in the range of 2 to 5, e.g. 3.

It should be noted that the extent of the branching of the acyclic hydrocarbon group attached to the methylene group in the alkyl aromatic hydrocarbon produced as above described can be calculated as follows (where '[l'l decyl oxo" alcohol is used as the starting material). If; is known (from a combination of physical methods such as infrared analysis and mass spectroscopy) that the in: decyl alcohol commercially prepared by oxo process consists primarily 'of 2,4,6,8-tetramethylnonanols. Therefore, since the coupling of the tetramethylnonyl bromide to the benzene group occurs at the carbon atom bonded to the bromine atom, the longest straight chain of carbon atoms attached tothe benzene group contains 9 carbon atoms. Thus,'9 of the 13, or 70%, of the carbon atoms in the alkyl group of the alkyl benzene compound are in a straight chain of carbon atoms.

(2) An oxo aldehyde prepared as above described, e.g., prepared from a tetrapropylene fraction, is reacted with the Grignard reagent of a benzene halide, e.g. the Grignard reagent of bromo benzene at temperatures of 20 C. to 40 C., e.g. 15 C., to obtain a condensation product. The molar ratios of Grignard reagent of a benzene halide to oxo aldehyde may be in the range of 1 to 2, e.g. 1.2:1. The condensation product obtained is then hydrolyzed at temperatures of 0 to 50 C., e.g. 20 C., to yield the secondary alcohol. This alcohol isthen dehydrated to the olefin at temperatures of 100 to 300 C., e.g. C., in the presence 'of a solid catalyst such as alumina, thoria, titania, aluminum silicates, sodium bisulfate or aqueous sulfuric acid, etc., e.g. alumina. The olefin so produced is then reduced by hydrogenation at temperatures of -20 to 100 C., e.g. 35 C., in the presence of a hydrogenation catalyst such as platinum, palladium, or nickel, e.g. platinum, to the desired alkyl benzene. Although in the steps involved above such as coupling of a Grignard reagent with an aldehyde, hydrolysis to the alcohol, dehydration to the olefin and bydr-ogenation of the olefin certain procedures have been described, it is of course contemplated that the other alternate-methods described in standard texts of organic chemistry may also be use-d. This is true also of the steps in the preparations described below.

(3) An oxo derive-d alkyl halide produced as described in Method of Preparation 1 above, e.g. prepared from a tetrapropylene fraction is reacted with a substituted benzene wherein one of the hydrogen atoms attached to an aromatic ring carbon atom 'is replaced with an alkali metal, forexample, phenyl sodium-or phenyl lithium. The desired condensation is obtained at temperatures of l0 to C., e.g. 35 C., utilizing molar ratios of the alkyl halide t-o alkali metal substituted benzene in the range. of 0.8to 2.0,e.g. 1.221, to obtainthezdesired alkyl benzene. v

(4) An oxo aldehyde prepared as described in Method of Preparation 1 above, e.g. prepared from a tetrapropylene fraction, is oxidizedto the acid at temperatures of 20 to 100 C., e.g. 60 C., .utilizing 0.5 to 3 moles, e.g. 1.2 moles, of an oxidizing agent such as alkaline permanganate, hydrogen peroxide, organic peracids, silver oxide, and molecular O e.g. hydrogen peroxide. The product acid is converted to an acid chloride-by means of PCl or thionyl chloride, e.g. 'PCl and is then reacted with benzene in the presence of a catalyst such as aluminum chloride, ferric chloride, etc., e.g. aluminum chloride at temperatures of 0 to80 C., e.g. 20 C., utilizing molar ratios of benzene to acid in'the range of 2 to 10, e.g. :5::-1, :to give a carbonyl link between ithebranched alkyl group and the aromatic ring. The carbonyl group link in this product is then reduced to a methylene group by means of zinc and a strong acid, i.e. HCl, or by means of hydrazine and alkali, i.e. NaOH, or by means of hydrogen in the presence of a catalyst such as nickel, palladium or platinum, e.g. platinum, at temperatures of 20 to 100 C., e.g. 50 (1., and pressures of atmospheric to 50 atmospheres, e.g. 5 atmospheres, to give the desired alkyl benzene.

(5) The acid described above in Method of Preparation 4, e.g. prepared from a tetrapropylene fraction, may also be obtained by saponification of a lower alcohol ester obtained directly by performing the hydroformylation reaction in the presence of a (E -C monohydric alcohol, e.g. methanol, as described in US. Patent 2,688,627. Thus, temperatures of 100 to 200 C.,e.g. 150 C., pressures of 2500 to 4000 .s.i.g., e.g. 3000 p.s.i.g., 1.0 to 3.0, e.g. 2.0, moles of CO per mole of olefin, 1 to 10, e.g. 5, moles of alcohol per mole of olefin and 0.1 to 5.0 wt. percent of a cobalt catalyst, e.g. cobalt oleate (calculated as the metal and based on the olefin) are used. The resulting carbo alkoxy derivative after decobalting is then converted to its corresponding carboxylic acid by hydration with a moderately dilute acid, e.g. 20 wt. percent sul- *furic acid, used with or without the addition of an agent capable of depressing the interfacial tension such as mahogany sulfonates, Twitchell agents and the like. Alternatively, the ester may be saponified in conventional manner by means of an excess of alkali. The acid is then reacted as previously described in Method of Preparation 4 to obtain the desired alkyl benzene.

(6) An aldehyde of the type described above in Method of Preparation 1 may also be prepared by a combination process in which the monomeric olefins are fed to the oxo process and hydroformylation and dimerization occur at the same time. Such a process is described, for example, in US. Patents 2,820,067 and 2,811,567. The process is operated by passing the olefin, hydrogen, CO, a cobalt carbonylation catalyst and a reaction modifier such as a zinc comprising material, e.g. zinc oleate into a carbonylation zone operated at temperatures of 200 to 400 C., e.g. 375 C., and pressures of 1500 to 4500 p.s.i.g., e.g. 3000 p.s.i.g. The H and C are supplied in a ratio of from 0.5 to 2, e.g. 1, volumes H per mole CO, while the cobalt salt is supplied to the extent of 0.2 to 0.5, e.g. 0.2 wt. percent, calculated as metal on olefin feed, and the zinc to the extent of 0.05 to 0.5, e.g. 0.1 wt. percent, again calculated as metal on olefin feed. Reaction times are 2 to 48, e.g. 8, hours. The aldehyde formed is then decobalted to remove suspended cobalt and reaction modifier components. The aldehyde is then reacted to obtain the desired hydrocarbon product by any of the methods previously described. As an example of this modified 0x0 process, pentene may be oxonated in the presence of modifiers, for example, zinc salts, so as to obtain a dimer alcohol having the general composition of C H CH(CH OH)(C H In simi lar manner a primary tetradecyl alcohol may be made by oxonating either hexenes made by catalytic cracking process or hexenes obtained by polymerizing propylene, to give an aldehyde having the general composition 11 2 i r ra) (7) A fraction of polymeric U.O.P. olefin as above described, for example, tetrapropylene or triisobutylene is converted to a halide by reaction with a halogen acid, e.g. HCl, at temperatures of 20 C. to 20 C., e.g. 0 C. and pressures of 1.0 to 5 atm., e.g. 1.0 atm, The resulting alkyl halides are then reacted with either:

(a) 0.1 to 1, e.g. 3, moles of toluene per mole of alkyl halide in the presence of 1 to 2 e.g. 1.2, molar proportions of an alkali metal, e.g. sodium, based on alkyl halide, at temperatures of 20 to 110 C., e.g. 50 C.; or

(b) 0.5 to 1.5, e.g. 1, mole per mole of alkyl halide of an alkali metal benzyl product (produced by treatment of a benzyl halide with an alkali metal or of toluene 0.8:1 to 2.25:1, a 1:1 ratio being suitable.

with reagents such as potassium-sodium oxide) e.g.

sodium benzyl, at temperatures of 0 to 120 C., e.g.

50 C., to give the desired alkyl benzene hereinbefore described. It should be noted that in the reaction with the halogen acid to obtain the alkyl halide that conditions may be varied to obtain either normal or abnormal Markownikoif addition products. If lengthening of the longest alkyl chain is desired, abnormal Markownikoii addition should be promoted by the use of oxygen, light, peroxides, or ganic acid promoters and free radical initiators in such a reaction. In general abnormal Markownikofi addition is preferred.

The alkyl benzenes are then sulfonated by conventional means to obtain the desired alkyl aryl sulfonic acids for detergents, e.g. by contact with an excess of concentrated sulfuric acid. The sulfonation may be carried out at temperatures up to 50 C. The acid concentration is preferably at least 97%. Acid up to 100% concentration and oleum, containing up to 20 wt. percent S0 or higher, may be employed. With higher acid concentration, lower reaction times are required, e.g. about 8 hours with 98% acid and one hour with 100% acid. Volume ratios of sulfuric acid to hydrocarbon may range from The larger the ratio, the more inorganic sulfate will be present in the product, following neutralization. In many cases, the inorganic sulfate is a desirable constituent of the finished detergent composition.

The sulfonation product mixture is preferably freed, e.g. by decanting, from unsulfonated hydrocarbons. The mixture is then neutralized, the sulfonic acids being thus converted to sulfonic acid salts and the excess sulfuric acid into sulfate. The neutralization may be carried out with any base or basic reacting inorganic or organic substance. Thus, to produce sodium sulfonates, aqueous sodium hydroxide or sodium carbonates are suitably employed. Other alkali metal, alkaline earth metal, ammonium or amine salts may be similarly produced from the corresponding basic compounds. The neutralization is generally carried out by contact with the aqueous solution at temperatures of from 20 to 100 C., those between and C. being preferred. The relative amounts of oil soluble and water soluble detergents obtained is of course dependent upon the distribution or amounts of the various chain lengths of the alkyl groups on the benzene ring and also on the average chain length of these alkyl groups.

Neither the methods used for preparation of the desired alkyl benzene hydrocarbons, nor the method for preparing the detergent materials described above, nor the examples which follow are to be construed as limiting the methods which are suitable for the preparation of these materials, since other methods for accomplishing the desired end as described are known in the art.

EXAMPLE I.TRIDECYCL BENZEN E A commercial letrapropylene fraction boiling in the range of 180 C. to 220 C. made by polymerizing propylene containing a small amount of butenes Over a phosphoric acid on kieselguhr catalyst, was oxonated in the presence of 2 Wt. percent of a cobalt oleate catalyst utilizing 1.3/1 ratio of H /CO, a temperature of 150 C. and a pressure of 3000 p.s.i.g. The resulting aldehyde was reduced to a primary alcohol with hydrogen with the aid of a nickel catalyst and the alcohol after fractiona tion boiled at 173 to 176 C. at a pressure of 51 mm. Hg. The alcohol was converted to the bromide by contacting it with anhydrous HBr at a temperature of C. and atmospheric pressure. After purification and fractionation, the tridecyl bromide boiled at 75 to 78 C. at a pressure of 0.8 mm. Hg.

Two hundred and sixty-three grams of the tridecyl bromide were mixed With 157 grams of bromobenzene and subjected to a Wurtz-Fittig reaction using 60 grams of sodium at a temperatureof 35 C. Afterfisolationand 'refrac'tionation, "an alkylate was'obtained which boiled showed on analysis a carbon content of 87.71% and "the end point. 'fonate was substituted for the sodium tridecyl benzene cle-a'nsingjand the color disappears in the foamjust before A conventional 'tetrapropyl benzene sulsulfonate and was compoundedin the same concentrations as above and was tested for dishwashing in comhydrogen cont t f 12 29%, Analysis f the tridecyl parison with the product made in Example 11, giving the benzene by' means of a high temperature mass spectromeresults shown below in Table I.

ter showed the following composition: TABLE 1 1s11w ASKING TESTS Percent C benzene 1.02 d Ndil iber C12 benzene 25.40 not s lishes C benzene 60.85 Ion Washed C14 benzene 2 'lridecyl benzene 0.,01 "10 12 The ratio of the mass peaks at 119/91 equaled 0.100. gg y 'g g a g m 8:3? 3% This latter ratio as discussed. previously indicated the 15 Do 0. 03 15-16 high proportion of the alkylate which is of the A V EXAMPLE IV type as c e to i d' m CH n An additional amount of the sodium benzene s'ulfonate R2 prepared as described above was again compounded into I] a detergent also as described above and'tested in comparison with a number of other 'detergents'in a standard "R1 cloth washing test. From the data obtained, presented types below, it'can be'seen thatj'again'this material showed much improved results over the prior art tetrapropyl ben- EXAMPLE BENZENE zene commercial similarly built detergent material. In I the table US. stands for U.S. Testing Company, Dry Fifty grams of the tridecyl benzene prepared in Exam- Soiled Cloth; and TE. stands for TestFabric, Inc., 'ple 1 were sulfonated with 70 grams of 20% oleum in Oily Soiled Cloth.

TABLE II [Cotton detergency140 F.]

Concentration 0.03% 0.05% 0.10%

Water hardness 2 Gr. 8 Gt. 8 Gr. 8 Gr.

sen type U.S. T.F. U.S. T.F. U.S. m. U.S. 1 .1

Sample VAR tridecylbenzene detergent 11.6 23.3 8.9 23.2 10.6 21.4 10.0 22.7 Commercial sold similarly built tetrapropylbenzene detergents 5.7 11.7 5.1 10.2 8.0 12.9 10.6 16.2

cloth.

. k p H Wt. percent fiSodiurn 'tridecyl benzene sulfonate 15 fSodiumsulfate 40 "'Sodiummetasilicate (a'nhyd) 5 Sodium tripolyphosphate 30 Sodium tetrapyrophosphate 1O The test consisted in washing 8 inch white dinner plates,

havingjlJS grams of a hydrogenated vegetable shortening distributed over the' surface, in 6 liters of detergent solution made up with 2 grains hard Water in a dishpan weight percent based on the active ingredient content until r oarn disappearance occurred. A trace of a colloidaldye,'dispersed in the shortening, indicated lack of AR-Inerease in percent reflectance after washing compared to unwashed, soiled EXAMPLE V.BIOLOGICAL DEGRADATION A sample of the sodium tridecyl benzene sulfonate prepared as described in Example II was tested in comparison with a commercial detergent sulfonate prepared by alkylating benzene with tetrapropylene (the commercial detergent having present also 19 wt. percent of sodium sulfate and water). The equipment consisted of two banks of 4 glass columns each about 3 ft. high and 2 inches in'diameter. The columns were packed with beds of Nottingham granite on which colonies of bacteria had been developed over a period of weeks. In each case a solution of the tW0 detergents to be evaluated (about 1 liter of concentration 10 to 50 ppm.) together with a standard nutrient for the bacteria (m alto-peptone) was added to each column and was circulated slowly around the system by means of an air pump. This insured that the column remained aerobic, the solution being circulated through the granite bed about seven times an hour. This type of submerged digesterf system is reasonably representative of the percolating filter type of commercial sewage plant which, according to Government reports, is used at sewage works serving about 22 million of the population of the United Kingdom.

Samples were drawn from the columns after 15 minutes and after 1 hour, 2 hours and 24 hours. The quantity of detergent remaining in each sample was extracted with chloroform and the intensity'of blue color developed with methylene 'blue' was 'measured by a photoelectric absorptiometer in accordance with the standard method to obtain the percentage of detergent remaining in the sample.

The following data Were obtained and are shown in the following table.

TABLE III [Initial concentration 3060 p.pr1n.]

Wt. percent degraded alter Initial Detergent cone,

p.p.m. 15min. 1 hour 2 hours 24 hours 51. 8 54 71 79 96 Sodium trideeyl benzene 51.8 55 71 81 99 sullen-ate. 55, 7 58 82 1 52. a s9 68 88 50. 9 67 76 87 94 50. 17 31 2 9 23 Commercial tetrapropyl g benzene sull'onate (con- 8 18 20 2g 53 taining also 19 wt. percent 0 26 21 34 32 sodium sulfate and water). 34 32 51. 5 27 18 38 It is to be understood that this invention is not limited to the specific examples, which have been offered merely as illustrations, and that modifications may be made without departing from the spirit of this invention.

What is claimed is:

A hydrocarbon mixture suitable for sulfonation to form detergents consisting essentially of monoalkyl benzene hydrocarbon having the general formula RCH 10 R wherein R is benzene, R is a tetrapropylene radical and the degree of branching of R is such that about to of the total carbon atoms in the alkyl group (including the methylene group) are in a straight chain of carbon atoms.

References Cited by the Examiner UNITED STATES PATENTS OTHER REFERENCES Dyson, A Manual of Organic Chemistry, Vol. I (1950), page 72, pub. by Longmans, Green & Co.

Egloff, Physical Constants of Hydrocarbons, published by Reinhold Publ. Co. (N.Y.), 1946 (page relied upon).

DANIEL E. WYMAN, Primary Examiner.

LEON ZITVER, MILTON STERMAN, ALPHONSO D.

SULLIVAN, Examiners.