US3501544A - Process for treating detergent alkylate - Google Patents

Description

United States Patent 3,501,544 PROCESS FOR TREATING DETERGENT ALKYLATE George L. Hervert, Downers Grove, Ill., assignor to Universal Oil Products Company, Des Plaines, Ill., a corporation of Delaware No Drawing. Continuation-impart of application Ser. No. 592,760, Nov. 8, 1966. This application Nov. 13, 1967, Ser. No. 682,659

Int. Cl. C07c 7/00 US. Cl. 260-674 Claims ABSTRACT OF THE DISCLOSURE A linear alkylaromatic detergent alkylate fraction that is substantially free of benzene is reduced in olefinic and nonlinear alkylaromatic and alkylanthacene content by contacting with a removal agent consisting essentially of hydrogen fluoride.

CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of my copending application Ser. No. 592,760 filed Nov. 8, 1966.

This invention relates to the treating of detergent alkylates and more particularly relates to reducing the olefinic, nonlinear alkylaromatic and alkylanthracene con tent of a linear alkylaromatic detergent alkylate fraction that is substantially free of benzene. Thus, olefinic material and fused ring compounds which are responsible for the discoloration of the final detergent and the nonlinear alkylaromatic content, which produces a less biodegradable detergent than the linear alkylaromatic detergent alkylate, are simultaneously reduced. It has thus been found, that the treatment of a detergent alkylate substantially free of benzene prior to the introduction of a hydrophilic group therein, by contacting the detergent with an agent consisting essentially of substantially anhydrous hydrogen fluoride within a critical temperature range reduces, for example, the bromine index of the detergent and the nonlinear alkylaromatic and alkylanthracene content of said detergent.

In one embodiment, this invention relates to a process for reducing the olefinic, nonlinear alkylaromatic and alkylanthracene content of a substantially linear alkylaromatic detergent alkylate fraction that is substantially free of benzene which comprises contacting said alkylate with an agent consisting essentially of substantially anhydrous hydrogen fluoride in the liquid phase at temperatures of from about 90 F. to about 150 F. and recovering the treated detergent alkylate.

Other embodiments of my invention will be found in the following further detailed description of my invention.

Detergents essentially are composed of a complex molecule containing both a hydrophobic group and ,a hydrophilic group. The purpose of the hydrophilic group is to render the detergent molecule water soluble. The hydrophobic group solubilizes grease, dirt, etc. and thus aids in the cleaning step in which detergents are employed. A proper detergent molecule contains a proper balance between hydrophilic and hydrophobic groups in order to produce a detergent having the proper cleaning characteristics. The hydrophobic group is generally supplied by an organic hydrocarbon. It is known that the hydrophobic group is readily supplied by an alkylaryl group wherein the alkyl portion is a saturated hydrocarbon having from about 10 to about carbon atoms (C to C and preferably about 12 to 13 carbon atoms and the aryl portion is a mono-nuclear aromatic ring. The

3,501,544 Patented Mar. 17, 1970 alkylaryl compounds are readily prepared by alkylation of a mono-nuclear aromatic hydrocarbon with a monoolefin hydrocarbon having from about 10 to about 15 carbon atoms per molecule. The resulting monoalkylate product is called detergent alkylate. This detergent alkylate is rendered surface active by introducing a hydrophilic group into the aryl ring as for example by sulfonation and neutralization with caustic to produce the sodium alkylbenzene sulfonate detergent. The alkylation is carried out over an acid catalyst. A preferred acid catalyst is hydrogen fiuoride. However it has been found that the detergent alkylate product produced from a hydrogen fluoride-catalyzed alkylation reaction can discolor and cause a disagreeable odor in the alkylate product when converted to the final detergent product by sulfonation.

It is therefore an object of this invention to treat detergent alkylate such that when said alkylate is converted to a detergent compound formation which discolor and add a disagreeable odor to the detergent is minimized.

It is another object of this invention to reduce the olefinic content of detergent alkylate.

It is still another object of this invention to reduce the nonlinear alkylaromatic content of detergent alkylate.

It is a further object of this invention to reduce the alkylanthracene content of detergent alkylate.

Detergent alkylates of the alkylaryl variety are prepared by alkylation of a mono-nuclear aromatic molecule with a mono-olefin having from about 10 to about 15 carbon atoms per molecule. The mono-nuclear aromatic is preferably selected from the group consisting of benzene, toluene, xylene, ethyl'benzene, methylethylbenzene, diethylbenzene, mononitrobenzene, and phenol. Benzene is especially preferred. The mono-olefins are preferably prepared from petroleum or petroleum derived fractions in the C to C carbon number boiling range. This is readily accomplished by separating the paraflins in a kerosene fraction by techniques such as adsorption of the more polar components such as aromatics and naphthenes over a selective sorbent such as silica gel, activated carbon, molecular sieves or by the use of a selective solvent. In any event a relatively pure parafiin fraction in the C to C boiling range is obtained. These parafiins may be converted directly to mono-olefins by dehydrogenation over a suitable dehydrogenation catalyst or the paraflins may indirectly be converted to monoolefins by a halogenation step followed by a dehydrohalogenation step. In some cases, it is preferred only to use the normal or straight chain paraffins so as to produce a linear alkyl benzene sulfonate detergent since these detergents are more readily biodegradable in subsequent sewage treating. When dehydrogenating the straight chain parafiins to produce straight chain mono-olefins the dehydrogenation catalyst must be of low acidity or preferably neutral or basic in order to minimize isomerization of the straight chain paraflins or, straight chain monoolefins. Straight chain paraflins are readily separated from kerosene mixtures in a suitable contacting apparatus containing molecular sieves having a pore opening of about 5 angstroms in diameter. A preferred process to attain this separation is that shown in US. Patent No. 2,985,589.

The mono-olefins are admixed with the mono-nuclear aromatic such as benzene and introduced into an alkylation reaction zone. The alkylation reaction is usually catalyzed by an acid-acting catalyst, preferably hydrofluoric acid. Preferably, excess benzene (relative to monoolefin) is employed in order to promote the mono-alkylation reaction. Therefore the alkylation reactor effluent contains an appreciable amount of benzene which is separated by fractionation and recycled to the alkylation reactor. When the mono-olefins are formed from the dehydrogenation of paraffins there will also be appreciable amounts of unreacted paraflins in the C -C carbon number range in the alkylation reactor efl luent which are separated from the detergent alkylate by fractionation and recycled to the dehydrogenation step.

It has been found that if the separated detergent alkylate, that is, the substantially linear alkylaromatic detergent alkylate fraction that is substantially free of benzene, is contacted with an agent consisting essentially of substantially anhydrous hydrogen fluoride at temperatures of from about F. to about 200 F. andpreferably of from about 90 F. to about 150 F, there will be a decrease in olefinic, nonlinear alkylaromatic and alkylanthracene content which in turn will allow the produc tion of detergents free of discoloration and disagreeable odors. By substantially anhydrous hydrogen fluoride, I mean that the hydrogen fluoride is of high purity that is above 90% by weight and preferably above about 95% by weight. Especially preferable are hydrogen fluoride purities in excess of 98% by weight. My invention is accomplished by separating the excess benzene and paraffins (if present) and then contacting the detergent alkylate substantially free of benzene with hydrogen fluoride at temperatures within the above critical temperature range. This will result in the ultimate production of satisfactory detergent. Suitable contact times between the detergent alkylate and the treating hydrogen fluoride are from about 1 minute to about 24 hours preferably from about 2 minutes to about 24 hours.

The following examples are introduced for the purpose of illustration only, with no intention of unduly limiting the generally broad scope of the present invention.

EXAMPLE I A substantially linear alkylaromatic detergent alkylate substantially free of benzene, namely a substantially linear alkylbenzene detergent alkylate fraction substantially free of benzene comprising C ',C linear alkylbenzenes and C C alkylate bottoms with a Bromine Index of 140, a nonlinear alkylbenzene content of greater than about 6.8 weight percent and 54 p.p.m. alkylanthracenes was placed in a reactor. Specifically, 4500 ml. of this detergent alkylate fraction was placed into a 2-gallon reactorwhich was then sealed and heated to about 91 F. by means of a water bath. Anhydrous hydrogen fluoride (2593 grams) was then pressured into the reactor, below the hydrocarbon, in a period of 9 minutes. Pressure was maintained at about 24 p.s.i.g. Stirring of the reactor contents was started. After a contact time of 15 minutes at an average temperature of 93 F., the reactor contents were allowed to settle and cool to about 46 F. The HP phase was then withdrawn into ice. The hydrocarbon was recovered, washed and dried.

The treated alkylate product was found to have a Bromine Index of 48 as compared to the alkylates original Bromine Index of 140. The nonlinear alkylbenzene content of the treated alkylate was 6.8 weight percent. The alkylanthracene content of the untreated alkylate, as set forth above, was 54 p.p.m. The treated alkylate product was found to have an alkylanthracene content of 3.5 p.p.m.

EXAMPLE II Similar results were also obtained utilizing the process of the present invention when a substantially linear alkylbenzene detergent alkylate fraction substantially free of benzene comprising C -C alkylate was placed in a reactor.

After a contact time of about 15 minutes, and a temperature of about F., and a pressure of about 66 p.s.i.g. at a HF/hydrocarbon volume ratio of 1:1, the treated alkylate was found to have a Bromine :Index of 2 as compared to the alkylates original Bromine Index of 47. The nonlinear alkylbenzene content of the treated alkylate was found to be 10.4 weight percent 'as compared to the untreated alkylates nonlinear alkylbenzene content of 13.6 weight percent. The alkylanthracene content of the alkylate was reduced from 0.8 p.p.m. for the untreated alkylate to 0.2 p.p.m. for the treated alkylate.

I claim as my invention:

1. A process for reducing the content of impurities selected from the group consisting of olefins, nonlinear alkylaromatics and alkylanthracenes of a substantially linear alkylaromatic detergent alkylate fraction that is substantially free of benzene and which contains at least one of said impurities, whichprocess comprises contacting said alkylate with an agent consisting essentially of substantially anhydrous hydrogen fluoride in the liquid phase at temperatures of from about 0 F. to about 200 F. and recovering the treated detergent alkylate.

2. The process of claim 1 further characterized in that the detergent alkylate is derived from the alkylation of a mono-olefin having from about 10 to about 15 carbon atoms per molecule and a mono-nuclear aromatic.

3. The process of claim 2 further characterized in that said mono-olefin is a straight chain mono-olefin.

4. The process of claim 2 further characterized in that the aromatic is selected from the group consisting of benzene, toluene, xylene, ethylbenzene, methylethylbenzene, diethylbenzene, mono-nitrobenzene and phenol.

5. The process of claim 2 further characterized in that the treating temperature is in the range of from about 90 F. to about F.

References Cited UNITED STATES PATENTS 2,366,743 1/ 1945 Matuszak 208280 XR 2,556,644 1/1951 Brooke et a1.

2,851,503 9/ 1958 Shifller.

3,349,144 10/ 1967 Alul et a1.

DELBERT E. GANTZ, Primary Examiner C. R. DAVIS, Assistant Examiner US. Cl. X.Rv