3,297,748 United States Patent Office Patented Jan. 10, 1967

1. 2 was found to have superior odor qualities, based upon 3,297,748 ALKYLBENZENE SULFONATE COLOR AND odor ratings made by subjective panel testing. ODOR INHIBITION By sulfonation is meant the treatment of alkylbenzenes John B. Wilkes, Albany, Calif., assignor to Chevron Re with concentrated sulfuric acid, and particularly with search Company, a corporation of Delaware concentrated sulfuric acid-sulfur trioxide mixtures, there No Drawing. Filed June 13, 1963, Ser. No. 287,489 by to produce the corresponding alkylbenzene sulfonic 2 Claims. (CI. 260-505) acids. Preferably, the present process contemplates the use of oleum having from about 5 to 28 percent sulfur This invention relates to an improved method for the trioxide content, by weight. In general, sulfonation reac preparation of branched-chain alkylbenzene sulfonate de 0 tion temperatures useful in the process range from about tergents. More specifically, this invention relates to the 50 to 150 F.; and, as is known in the art, from about a preparation of branched side-chain alkylbenzene sulfo stoichiometric amount to about a 20 percent excess of nate detergent by the sulfonation of branched-chain alkyl the sulfonating agent, based upon the alkylbenzene, is benzenes with oleum in the presence of color and odor preferably used. Usually, the sulfur trioxide in the oleum inhibiting amounts of acetic acid and a lower alkylben mixture is the sulfonation agent consumed, although the ZCle. sulfuric acid may also be consumed to the point where The active ingredient in most detergents in household the residual sulfuric acid medium has been reduced use are alkylated aryl sulfonates. For aesthetic reasons, through the production of water in the alkylation reac color and odor properties of these detergents are, there tion to about 96 percent sulfuric acid. fore, of particular importance, for, although color and 20 While the presence of minor amounts of any lower odor bodies appear to have no other effect on the prop alkylbenzene and similar minor amounts of acetic acid erties of the detergent, these properties do have a large during oleum sulfonation of branched-chain alkylbenzene effect on the acceptance of the product by the trade. detergent alkylates results in appreciable color and odor While many process methods have been proposed for improvements of the product, those lower alkylbenzenes the treatment of the finished product for the elimination 25 represented by the formula: of color and odor bodies from the crude alkylbenzene sul fonates, the more practical solution of the problem ap CHCRRH pears to be the substantial inhibition of the production wherein R1 and R2 may be methyl, ethyl, and propyl, are of these bodies in the formative process. particularly effective in connection with the presence of The concurrent formation of color and odor bodies is 30 acetic acid in the inhibition of color and odor body forma a particular problem in the conversion of branched-chain tions. In some measure at least, the reason for the alkylbenzene feeds to the corresponding alkylbenzene sul superiority of the above preferred lower alkylbenzenes is fonates, by use of oleum under sulfonating conditions. believed associated with the ease of carbonium ion forma In general, the present invention is useful in the sul tion of these materials under the oleum sulfonation con fonation of alkylbenzene compounds in which the alkyl 35 ditions. group contains from 9 to 18 carbon atoms, although rela The examples following are given for purposes of illus tively smaller amounts of dialkylbenzene and of higher tration, and it is to be understood that the invention is not and lower molecular weight alkylbenzenes may be pres to be limited to the specific conditions or details set forth, ent in admixture. As is known in the art, alkylbenzene but only insofar as such limitations are specified in the feeds having side chains averaging from about 12 to 15 40 appended claims. carbon atoms per side-chain group yield superior deter Examples gents. The present invention is particularly advantageous The sulfonations from which the following experiment in the preparation of this molecular weight range deter al results were obtained were carried out in sulfonation gent sulfonate and especially with those branched side equipment, as detailed in Fig. 1 in the paper of T. H. chain alkylbenzene feeds having from 1 to about 6 lower 45 Liddicoet and S. A. Olund, Journal of American Oil alkyl, usually methyl, side-chain branching groups per Chemists Society, Vol. 40, No. 1, pages 5-10 (1963). molecule. Representative branched side-chain alkylben The experimental procedure employed was in accordance Zene hydrocarbon feeds are the detergent alkylates ob with the standardized batch oleum sulfonation procedure tained by the alkylation of benzene with polypropylene of the reference, except for the following changes: obtained by the phosphoric and sulfuric acid catalyzed 50 (1) a nitrogen atmosphere was maintained; polymerization of propene, including propylene tetramer (2) digestion temperatures and times were: benzene alkylate, propylene pentamer benzene alkylate, (a) mild sulfonation-80 to 85 F. for 120 minutes, and and the like. Other useful feeds include benzene alkylate (b) severe sulfonation-120 F. for 60 minutes; and obtained by the use of triisobutylenes, mixed polymers of (3) setting temperatures and times were: propene and butenes, isobutene trimer benzene alkylate, 55 (a) mild sulfonation-135 to 140 F. for 120 minutes, and the like. and It has now been found that the color and odor charac teristics of branched-chain alkylbenzene sulfonates hav (b) severe sulfonation-150 to 155° F. for 60 minutes. ing from 9 to 18 carbon atoms per side-chain group are In both the mild and severe sulfonation treatments, the greatly improved when the corresponding alkylbenzene 60 Subsequent processing steps were the same as indicated in hydrocarbon is sulfonated with oleum in the presence of the reference. The experimental color values for the from 0.5 to 6.0 percent each, based upon the weight of finished alkylbenzene sulfonate products are those values the alkylbenzene, of acetic acid, and of a lower mono obtained for 2 percent by weight sulfonate solutions ex alkylbenzene hydrocarbon having from 1-7 carbon atoms pressed in terms of percent saturation, using the interna 65 tionally defined ICI tri-stimulus, Hardy, A. C., “Handbook per alkyl group. Detergent sulfonates prepared in this of Colorimetry,” The Technology Press, MIT, Cam manner show marked reduction in color body content, bridge, Massachusetts, 1936, and the procedure is de being as much as 50%, based upon standard runs. At scribed by R. House and J. L. Darragh, Analytical Chem the same time, the product produced by the present process istry, vol. 26, page 1492 (1954). 3,297,748 3. 4. Examples 1-11 As in the case of Runs 1-11, inclusive, it is to be seen POLY PROPYLENE TETRAMER BENZENE ALKYLATE - from Runs 12-20 above, made with polypropylene penta Av. Imol. wt. 242-245, 22% oleum mer, that the oleum sulfonations of branched-chain alkyl Mild Sulfonation, N. Atmosphere benzenes are improved in large measure by effecting these 5 sulfonations in the presence of added acetic acid and lower alkylbenzenes. Percent, Percent, Wt. Color, Percent Run No. Wt. HOAc Alkylbenzene, Saturation, This invention has been described with particular refer Cunene 2%. Solution ence to preferred embodiments thereof; nevertheless, it will be understood that variations in these embodiments 3.5 can be effected without departing from the inventive con 2.5 0. cept. I claim: 1. In a process for producing a branched-chain mono alkylbenzene sulfonate detergent at a temperature in the (5.8) 5 range from about 50 to 150 F. by sulfonating with oleum a branched-chain monoalkylbenzene hydrocarbon having from 9 to 18 carbon atoms in its alkyl chain, the im provement which comprises sulfonating said alkylbenzene in the presence of from 0.5 to 6.0 weight percent each, Extra Severe (2.5 Moles 28.7% Oleum/Mole Alkylbenzene at 60–65 F. 20 based upon the weight of the branched-chain alkylbenzene, No Digestion) of acetic acid and of a lower alkylbenzene represented by the formula: 10------CH-CRR2H ill------2.0 2.0 wherein R1 and R2 is methyl, ethyl, or propyl and there 25 by producing branched-chain monoalkylbenzene sulfo From the above examples, it is to be seen that whether nates having improved color and odor characteristics. the sulfonation conditions be mild or severe, the presence 2. In the production of branched-chain monoalkylben of cumene (Runs 1, 2, 3, 10, and 11) improves the product zene sulfonate detergent at a temperature in the range color. Thus, Run 2 yields a color about 30 percent better from about 50 to 150 F. by sulfonating with oleum a than Run 1, and Run 11 is about 42% better than Run 30 branched-chain monoalkylbenzene hydrocarbon having a 10. From a comparison of Runs 4-9, inclusive, it is to side chain of from 9 to 18 carbon atoms, the improvement be seen that as little as 0.5 wt. percent of added acetic which comprises sulfonating said alkylbenzene in the acid used with cumene causes an appreciable improve added presence of from about 0.5 to 6.0 weight percent ment in product color, whereas little added improvement each, based upon the weight of the alkylbenzene, of acetic is to be expected by using amounts of acetic acid in ex 35 acid and of cumene, thereby producing branched-chain cess of 6%. Run 8 shows that the color improvement monoalkylbenzene sulfonates having improved color and can exceed 50%. odor characteristics. Examples 12-20 References Cited by the Examiner POLYBROPYLENE PENTAMER BENZENE ALKYLATE 40 Av. mol. wt. 264-267, 22% oleum UNITED STATES PATENTS Mild Sulfonation, N, Atmosphere 2,694,086 11/1954 Mitchell et al. ------260-505 2,704,295 3/1955 Gilbert et al. ------260-505 Percent, Color, Percent 2,820,015 1/1958 Smith ------260-505 Run No. Wt. HOAc Percent, Wt. Alkylbenzene Saturation, 45. 2,831,020 4/1958 Norwood et al. ------260-505 2%, Solution 2,889,360 6/1959 Brooks ------260-505 2------4.5 2,897,156 7/1959 Lewis ------260- 505 13. 5.0, Cumene.------2.9 2,928,867 3/1960 Kirk et al. ------260-505 4- -- 5.7, Sec.-Butylbenzen - 3.0 -15- -- 3.9, Toluene.------. - 3, 6 3,042,713 7/1962 Schar ------. 260-505 6------4.6, Ethylbenzene.------4.1 50 . OTHER REFERENCES Groggins, Unit Processes in Organic Chemistry, 5th Severe Sulfonation, N. Atmosphere edition, 1958, pp. 310-311. 17------6.3 18------5.0, Cunene------4.1 55 LORRAINE A. WEINBERGER, Primary Examiner. 19------5.7, Sec.-Butylbenzen 4.4 20------2.0 5.0, Cumene------3.6 LEON ZITVER, Examiner. B. EISEN, M. WEBSTER, Assistant Examiners.