US3238249A - Alkylbenzene sulfonate production via n-olefin dimerization - Google Patents

Description

United States Patent 3,238,249 ALKYLBENZENE SULFONATE PRODUCTION VIA N-OLEFIN DIMERIZATION Stanley B. Mirviss, Westfield, James H. McAteer, Cranford, and Joseph F. Nelson, Westfield, N.J., assignors to Esso Research and Engineering Company, a corporation of Delaware N0 Drawing. Filed Sept. 23, 1960, Ser. No. 57,885 6 Claims. (Cl. 260505) The present invention relates to improved biodegradable alkyl benzene detergents and to processes for their preparation. More particularly, this invention relates to an improved detergent prepared by dimerizing a C -C predominantly straight chain olefin in the presence of an aluminum alkyl or a dialkyl aluminum halide catalyst, alkylating benzene therewith and sulfonating the resultant alkyl benzene to obtain the final product detergent. Most particularly this invention relates to utilizing a C -C predominantly straight chain alpha olefin stream from steam cracking as the feed to the process and to utilizing mild conditions in alkylation.

According to the present invention it has now been discovered that biodegradable detergents having excellent washing properties may be obtained by the process of this invention. A C -C predominantly straight chain olefin is dimerized in the presence of an alkyl aluminum catalyst to obtain an olefin predominantly of the following structure.

wherein R is a predominantly straight chain alkyl group of from 3 to 6, e.g., 4 carbon atoms, R is a predominantly straight chain alkyl group of from 5 to 8, e.g., 7 carbon atoms, and the extent of the branching of the alkyl groups is such that on the average less than 1.0, preferably less than 0.6 methyl group, in addition to the two terminal methyl groups, are contained in R and R. It should be noted that less than 10%, preferably less than 5%, of the branches R and R are higher alkyl groups, e.g., ethyl groups, rather than methyl groups. This olefin is then used to alkylate benzene to obtain an alkyl benzene having primarily (e.g., above 75%, preferably greater than 85) the following structure:

wherein R and R are as above described and wherein again the extent of the branching of the alkyl groups is such that on the average less than 1.0, preferably less than 0.6 methyl groups, in addition to the terminal methyl groups, are contained in R and R. Thus, the olefin adds very selectively to the benzene through the tertiary carbon atom of the olefin. The small amount of other material formed is due mainly to isomerization of the olefin double bond occurring during alkylation and dimerization.

As is well known the two prime problems present today in detergent manufacture are the reduced washing properties obtained where detergents are used in soft water areas, and the problem of the poor biodegradability of conventional detergents, (i.e., capacity -to be removed in sewage disposal plants). With respect to the former of these problems, it is known that the washing efficiency of conventional alkyl benzene detergents obtained from tetrapropylene is reduced by approximately 20% in soft water areas. This is a very serious problem in view of the fact that in the United States, for example, more than 50% Patented Mar. 1, 1966 "ice of the population lives in these soft water areas, i.e., areas where the water contains 0 to 4.7 grains of calcium and magnesium salts per gallon.

With respect to the latter problem, the removal of detergent materials in sewage disposed plants so that the effluent from these plants does not introduce these active materials into rivers and streams is extremely important. Thus, severe fouling and foaming problems have been encountered in many countries due to the lack of biode gradability of conventional commercial detergents. It has now been discovered that the present material solves both of these problems and is easily and cheaply prepared.

Suitable feed stocks for use in the present invention process are C -C predominantly straight chain monoolefin streams obtained from commercial processes such as both mild and severe stream cracking. Both the entire C -C stream and selected fractions from this stream, e.g., a C stream, are preferred feed stocks. The extent of branching of the olefins in these feed stocks (on other than the ethylenic carbon atoms, i.e., the carbon atoms attached to the double bond) must be on the average less than 0.5, preferably less than 0.3 methyl groups per molecule. By methyl groups per molecule it is intended to include both methyl groups as such and other alkyl group branches. It should be noted that those olefins present in the feed stock which contain branches on either of the ethylenic carbon atoms do not react in the dimerization reaction and hence, of course, may be present in the feed wiithout deleterious effect on the dimer product. Other olefin containing feed stocks may also be utilized so long as they meet the above described requirement as to the extent of branching permissible. Paraffins and aromatics may be present in these feed stocks since they do not react in the dimerization reaction. Where these feed stocks contain diolefins and acetylenes, in a preferred embodiment these materials are removed by known methods such as extraction, hydrogenation, etc., to increase the purity of the dimer product obtained.

In one embodiment preferred C -C feed stocks are obtained from the low severity steam cracking of wax, petrolatum or a paraffinic gas oil. Temperatures of 10004200 F. and conversions to C minus of 5 to 15 wt. percent are used to produce mainly C -C monoolefins. It should be noted that in a preferred embodiment these olefins are obtained from low conversion steam cracking processes conducted in the vapor phase. The amount of steam utilized is not critical, in general 50 95 mol percent steam based on total feed plus steam being used. The olefins boiling in the C -C range contain above wt. percent, preferably about wt. percent, straight chain olefins. Additionally these olefins are above 80 wt. percent alpha olefins. Although non-alpha olefins can be easily isomerized to alpha olefins during dimerization by having an additional catalyst present (as will be described) still some undesirable isomerization is obtained in such a modified dimerization process and therefore predominantly alpha olefin feed stocks are preferred.

In another embodiment preferred C C feed stocks are obtained by liquid phase thermal cracking a paraffinic feed stock of the type above described at temperatures of 800 F. to 1000 F., and conversions of fresh feed to lighter boiling products of 20 to wt. percent. By such a process 40 to 60% of predominantly straight chain olefins are obtained, the remainder, being paraffins and small amounts of diolefins. If desired, the olefins may be dimerized directly from the parafiins.

In another embodiment preferred C C feed stocks are obtained from the widely commercially used high conversion steam cracking of gas oils to produce commercially desirable C -C olefins and diolefins as Well as higher boiling materials. Temperatures of about 1250-1500 F., amounts of steam as above described and residence times to obtain conversion to C minus of 20 to 80 wt. percent are used in this process. The olefins boiling in the C C range from the high conversion steam cracking process may be treated by extraction to remove aromatics, if desired, or may be used without such a removal of aromatics. C -C cuts obtained from the high severity cracking of various gas oils or naphthas contain generally above 20 Wt. percent straight chain olefins and certain fractions obtained from paraflinic gas oils may contain as much as 60 Wt. percent straight chain olefins, or even 80 Wt. percent straight chain olefins. The amount of benzene present in a C -C cut is, e.g., to 30 wt. percent. As previously mentioned in one embodiment the benzene present (which boils in the C olefin boiling range) in the feed stream is not remove-d by extraction prior to dimerization since it is advantageous in this reaction, and in the following alkylation it supplies part of the feed benzene required.

It should be noted that the C -C olefinic streams from seam cracking above described are byproducts in the production of other more valuable materials and that these streams are ordinarily used only for their fuel value in gasoline. It is of course also contemplated that particular olefinic streams as above described, after conventional removal of more valuable components, e.g., aromatics, diolefins, etc., may be utilized. These feed streams are extremely inexpensive feed stocks for the present process.

In a final embodiment preferred C -C feed stocks are obtained by an ethylene growth process in the presence of aluminum alkyls. In this process, for example, ethylene is reacted with an aluminum alkyl, e.g., aluminum triethyl, at temperatures of 160 to 350 F. and pressures of 500 to 5000 p.s.i.a. to obtain C C aluminum trialkyls and these higher aluminum trialkyls are then reacted with an olefin to displace the higher alkyls and thus form C C olefins. A general discussion of this process is found in US. Patent 2,781,410. The desired C -C straight chain olefin feed stocks for the present invention are of course less valuable than the higher straight chain olefin main product.

Dimerization is carried out utilizing an aluminum trialkyl or dialkyl aluminum chloride catalyst preferably an aluminum trialkyl catalyst. Preferably the alkyl groups in these catalysts are C -C alkyl groups. The catalyst is used in quantities of from 0.5 to 20 wt. percent, preferably 2 to 10 wt. percent, e.g., 10 Wt. percent, based on the olefin in the feed. Preferred catalysts are aluminum trialkyl catalysts prepared from the feed olefins to be dimerized. Such catalysts, of course, do not contaminate the desired dimer product with different dimer materials formed from the catalyst alkyl groups. Other preferred catalysts are aluminum trialkyls branched at the beta carbon atoms of the alkyl groups, e.g., aluminum triisobutyl. These aluminum trialkyls do not react in the dimerization process and hence also do not contaminate the product.

An additional different catalyst may be employed if desired, particularly where the feed stock contains in addition to alpha olefins internally double bonded straight chain olefins. Thus, in such an embodiment a concurrent isomerization of these internally double bonded olefins is obtained so that the desired final product from the process is obtained. Suitable additional catalysts are nickel, cobalt, palladium, platinum and the like. Although these catalysts can be supported on inert supports such as alumina, it is preferred to utilize unsupported catalysts. The amount of this additional catalyst utilized should be in the range of 0.1 to 10, preferably 0.5 to 5, e.g., 1 wt. percent, based on the aluminum alkyl catalyst.

Additionally an inert solvent may be used such as a C -C acyclic or cyclic paraffin, e.g., normal pentane, hexane, heptane, etc. and isomers of these materials, and cyclopentane, cycloheptane, etc. Chlorobenzene, benzene and toluene may also be used. Where a solvent is used it is preferred to utilize a feed stock containing the diluent material. Particularly such a preferred diluent is an aromatic hydrocarbon which is to be a coreactant in the next step.

The dimerization reaction is carried out at temperatures in the range of 80 to 300 C., preferably 110 to 250 C., e.g. 190 C., pressures in the range of atmospheric pressure to 200 atmospheres, e.g., 170 atmospheres, utilizing reaction times in the range of 0.5 to 25 hours, preferably 1 to 20 hours, e.g., 4 hours. Preferably the reaction is carried out in a liquid phase. Following reaction, the dimer is separated, e.g., by distillation, from unreacted olefin and from aluminum alkyl material (and from diluent if a diluent is used). Alternatively the entire mixture after separation of aluminum alkyl material may be supplied to the alkylation step. The separated aluminum alkyls are, of course, preferably recycled to the reaction zone for reuse in dimerization.

Alkylation is carried out utilizing benzene or less preferably toluene, in the presence of a Friedel-Crafts type catalyst at temperatures in the range of 10 to C., e.g. 10 C. Preferred catalysts are, for example, AlCl HF, BF and AlBr polyphosphoric acid, H and aluminum chloride hydrocarbon complexes.

It is generally desirable to maintain in the reaction mixture a volume ratio of aromatic hydrocarbon to olefin of at least 3:1, e.g., 5:1, although ratios up to 20:1 may be used.

In the case of utilizing catalysts such as AlCl BF etc. preferably AlCl it is preferred to utilize in one embodiment mild conditions of 5 to 20 C., e.g., 10 C., and in another embodiment conventional conditions of 20 to 60 C., e.g., 45 C. In both of these embodiments weight ratios of olefin to catalyst are in the range of 30:1 to 10:1, e.g., 20:1. Additionally in the case of the use of aluminum chloride an activator such as HCl may be added in an amount of from 15 to 40 wt. percent, e.g., 20 Wt. percent, based on aluminum chloride.

In utilizing the liquid hydrogen fluoride catalyst it is preferred to use an acid to hydrocarbon reactants volume ratio of 0.1:1 to 1.021, e.g. 0.3:1 and temperatures in the range of 0 to 15 C., e.g., 10 C. The concentration of this catalyst may range from to HP by Weight, its water content being maintained very low, e.g., no higher than 1 or 2% by weight, the remainder being dissolved hydrocarbon material.

The alkylated aromatic fraction is recovered from the alkylation reaction mass and is sulfonated in known manner, e.g., by contact With an excess of concentrated sulfuric acid, oleum, ClSO H, sulfur trioxide, etc. The sulfonation may be carried out at temperatures up to 60 C., preferably for oleum 15 C. to 60 C., e.g. 50 C. The acid concentration is preferably at least 97%. Acid up to 100% concentration and preferably oleum, containing up to, e.g., 20 wt. percent S0 or higher, may be employed. With higher acid concentration, lower reaction times are required, e.g., about 3 to 4 hours with 98% acid, about 2 hours with 100% acid, and preferably 0.5 to 1 hour, e.g., 0.7 hour, with oleum. Volume ratios of sulfuric acid to hydrocarbon may range from 0.8:1 to 1.25:1, a 1:1 ratio being suitable. 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 may be separated by layering to remove part of the excess spent acid before neutralizing or may be neutralized directly. When neutralized, the sulfonic acids are thus converted to sulfonic acid salts and the excess sulfuric acid into sulfate. The neutralization may be carried out with any base or basic- Example 1 Run 1.-A .3-liter bomb was charged with 500 g. of hexane-1 and :50 g. of Al(nahexyl) wt. percent on olefin) and the bomb was heated at 185190 C. for 17 hours and then cooled. The contents were emptied and distilled. The products consisted of 356 g. of C olefin which was approximately 82% Type III olefin, 8% Type II (trans) olefin, less than 1% of Type I olefin according to infrared analysis, and the remainder being Type IV olefin. This infrared analysis was based on the spectra fractionation. The yield of alkylate was found to be 80 volume percent and was 99% pure C alkylate. It should be noted that tetrapropylene prepared by polymerizing propylene in the presence of phosphoric acid under similar conditions gives only a 72 volume percent yield.

Run 3.--The alkylate prepared as described in Run 2 was sulfonated with 20% oleum at 15 to 60 C. by adding the oleum to the alkylate. The weight ratio of oleum to hydrocarbon was 1.4:1 and the materials were reacted for 45 minutes. Following reaction, the sulfonation product mixture was neutralized to a pH of 7 with aqueous sodium hydroxide to obtain the sodium salts of the sulfonic acids admixed with sulfates produced from excess spent sulfuric acid. The neutralization was carried out at temperatures of about 45 C. utilizing a reaction time of about 15 minutes.

Example 2 The detergent material prepared as above described was tested for washing properties in dishwashin-g and in cotton laundering tests along with a conventional detergent prepared from tetrapropylene.

TABLE "1.DISHWASHING TEST a A detergent consisting of the sodium sulfonate of dodecyl (tetrapropyl) benzene.

for C olefins adjusted to C olefins. The non-type III C olefins arise from isomerization of the C Type III olefin, Z-nbutyl-octene-l. It should be noted that in general only Type I and II olefins will not produce the desired alkyl benzene structure on alkylation. Also 92 g. of hexene-l 'was recovered. The remaining product was 86 g. of alkyl aluminum compounds which had a composition corresponding to 90% Al(C and 10% Al(C The alkyl aluminum residue from the distillation can be reused in dimerization. The material balance was 97 Wt. percent and the losses were found to be only hexene-l occurring during distillation and venting the bomb of pressure after the reaction was completed. Thus 71% of the hexene-l charged was converted to C olefin, 18.5% of the hexene-l was unreacted, and 7% was converted to C alkyl aluminum compounds.

Run 2.-The C olefin was then used to alkylate benzene and AlCl in the conventional manner to form the dodecylbenzene, consisting essentially of 2-phenyl-2-nbutyl-octane. The C olefin as prepared above was used to alkylate benzene in a laboratory glass stirred reactor using a 5:1 volume ratio of benzene to olefin and using 5 wt. percent of aluminum chloride based on olefin as the catalyst. Benzene was run into the reaction flask at room temperature and HCl was then supplied to said flask. The glass reactor was then heated to 45-50 C. and /a of the total catalyst was added. Olefin addition was begun from a funnel, and when /3 was added in 15 minutes, olefin addition was temporarily discontinued and a further of the catalyst was added. A second /3 of the olefin was then added in another 15 minute period. A final of the catalyst was then added and complete addition of the final A of olefin was made over another 15 minute period. The reactor was stirred for an additional 15 minutes (total time 1 hour). The reactor was cooled to room temperature and the contents were transferred to a separatory funnel. The layers were allowed to separate while a hydrocarbon layer was recovered. This layer was then washed with water and dilute carbonate and then finally with water. The hydrocarbon product after excess benzene was stripped off was worked up by As can be seen the experimental detergent is much better in the runs marked with an asterisk, i.e. at low concentrations and in soft water.

TABLE 2.-COTTON LAUNDERING TEST [Terg-O-Torneter] B U.S. Testing Corporation cloth-dry and dirty both sides. b Test fabrics Company Cloth-oily and dirty one side.

The experimental and the commercial detergent are fully equivalent in the heavy duty cotton laundering test. Thus, the fully biodegradable nature of the present detergent is obtained without detriment.

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:

1. A process for preparing biodegradable alkylbenzene detergents which comprises selecting a C to C predominantly straight chain alpha olefin stream containing on the non-ethylenic carbon atoms, on the average less than 0.5 methyl groups in side chains, dimerizing the predominantly straight chain alpha C to C olefins in the presence of a catalyst consisting essentially of an alumina alkyl at temperatures in the range of to 300 C., pressures in the range of atmospheric pressure to 200 atmospheres and for reaction times in the range of 0.5 to 25 hours, separating olefin dimer from the reaction mixture, reacting benzene with the resultant olefin dimer under active alkylating conditions to produce alkylbenzene at least 75% of which having the structure wherein R is a predominantly straight chain alkyl group of from 3 to 6 carbon atoms, R is a predominantly straight chain alkyl group of from to 8 carbon atoms and the extent of branching of the alkyl groups R and R is such that on the average less than 1, preferably less than 0.6 methyl groups, in addition to the 2 terminal methyl groups is contained in R and R, contacting said alkylbenzenes with an active sulfonating agent at temperatures of about to 60 C. and neutralizing the reaction product with a basic aqueous solution at temperatures of from to 70 C.

2. A process according to claim 1 wherein the C to C straight chain olefin stream is obtained by steam cracking a gas oil at high conversion.

3. A process according to claim 2 wherein the C to C fraction from steam cracking is treated to remove the acetylenes and diolefins prior to being fed to the dimerization step.

4. A process according to claim 2 wherein the C to C fraction from steam cracking is extracted to remove aromatics prior to being fed to the dimerization step.

5. A process according to claim 1 wherein the C to C straight chain olefin stream is obtained by steam cracking of a paraffinic gas oil feedstock at temperatures in the range of 1000 to 1200 F. utilizing conversions to C in the range of 5 to 15 wt. percent.

6. A process for preparing an al'kylbenzene sulfonate detergent material which comprises dimerizing a stream of C to C predominantly straight chain alpha monoolefins containing on the non-ethylenic carbon atoms, on the average less than 0.5 methyl group in side chains, at temperature in the range of 150 to 200 C., at pressures in the range of atmospheric to 200 atmospheres, utilizing reaction times of 1 to 20 hours, in the presence of 2.0 to 10.0 wt. percent based upon the olefin in the feed, of a catalyst consisting essentially of Al(n -hexyl) separating olefin dimers from the reaction mixture, reacting benzene with said olefin dimers at temperatures of 20 to C., in the presence of an aluminum chloride catalyst using ratios of benzene to olefin dimers of about 3:1 to 20:1, sulfonating the resulting alkylated benzene with oleum at temperatures of about 15 to C. and neutralizing the resultant reaction product with a basic aqueous solution at temperatures of about 20 to C. to obtain an alkyl benzene sulfonate.

References Cited by the Examiner UNITED STATES PATENTS Horeczy 260505 2,612,531 9/1952 2,622,113 12/ 1952 Hervert 260-505 2,781,410 2/1957 Biegler et al. 260683.15 2,796,429 6/ 1957 Kreps et a1 260-505 2,813,917 11/1957 Sharrah 260-505 2,871,254 1/1959 HoOg et al. -2. 260-405 2,897,156 7/1959 Lewis 260505 2,984,691 5/1961 Fotis 260-671 X 3,009,972 11/1961 Johnson 260505 FOREIGN PATENTS 539,281 9/ 1941 Great Britain.

742,642 12/ 1955 Great Britain.

775,384 5 1957 Great Britain.

922,014 3/ 1963 Great Britain.

OTHER REFERENCES Hammerton, J. Appl. Chem., vol. 5, Sept. 1955, p. 522. Pot-olovskiy et al., Khimiya i Teknologiya Topliv i Masel, 1958, Nr. 6, pp. 3341, U.S.S.R.

LORRAINE A. WEINBERGER, Primary Examiner.

CHARLES B. PARKER, LEON ZITVER, Examiners.

Claims (1)

1. A PROCESS FOR PREPARING BIODEGRADABLE ALKYLBENZENE DETERGENTS WHICH COMPRISES SELECTING A C5 TO C6 PREDOMINANTLY STRAIGHT CHAIN ALPHA OLEFINSTREAM CONTAINING ON THE NON-ETHYLENIC CARBON ATOMS, ON THE AVERAGE LESS THAN 0.5 METHYL GROUPS IN SIDE CHAINS, DIMERIZING THE PREDOMINANTLY STRAIGHT CHAINALPHA C5 TO C6 OLEFINS IN THE PRESENCE OF A CATALYST CONSISTING ESSENTIALLY OF AN ALUMINA ALKYL AT TEMPERATURES IN THE RANGE OF 80 TO 300*C., PRESSURES IN THE RANGE OF ATMOSPHERIC PRESSURE TO 200 ATMOSPHERES AND FOR REACTION TIMES IN THE RANGE OF 0.5 TO 25 HOURS, SEPARATING OLEFIN DIMER FROM THE REACTION MIXTURE, REACTING BENZENE WITH THE RESULTANT OLEFIN DIMER UNDER ACTIVE ALKYLATING CONDITIONS TO PRODUCE ALKYLBENZENE AT LEAST 75% OF WHICH HAVING THE STRUCTURE