US 3169987 A
Description (OCR text may contain errors)
United States Patent Delaware N0 Drawing. Filed Dec. 30, 1960, Ser. No. 79,575
7 Claims. (Cl. 260-505) This invention relates to a process for the production of arylalkanes for subsequent conversion to surface active agents and particularly to such compounds which have optimum surface activity. More specifically, this invention concerns the production of aryl-substituted alkanes in whichthe aryl group occupies the 4- or the 5-position in the alkyl chain, produced by alkylating an aromatic compound containing a nuclearly replaceable hydrogen atom with a normal olefin in which the double bond occupies a position between the third and fifth carbon atoms in the olefin chain, the olefin being formed by isomerization of a normal olefin with an alkaline isomerization catalyst.
Research into the structure of detergents containing as the hydrophobic group an alkylaryl radical and research correlating the surface activities and other specific properties of the products has shown that the position of the aryl group on the alkyl chain of thehydrophobic radical markedly affects such physical properties of the surface active agent as foaming, wetting and washing power, solubility in water, etc., even though the total number of carbon atoms in the alkyl chain is identical. It has now been found and this finding forms the'basis' of the present invention that detergents prepared from aryl-substituted alkanes in which the aryl group occupies a position between the third and the fifth carbon atom in the alkyl chain produce optimum detergents, particularly detergents having maximum washing power and wetting power of all of the various position isomers capable of being produced by alkylation of an aromatic compound with the various position isomers of the normal olefins. It has also been found that detergents preparedfrom aromatic alkylates in which the aryl groups occupy a position between the third and fifth carbon atom in the alkyl chain are especially biologically soft detergents; that is, these detergents are capable of maximum degradation in the presence of sewage bacteria and therefore of maximum bacterial destructibility.
It is well known, of course, that a particular species of normal olefin may exist in a number of position isomers which differ from each other only in the position of the double bond constituting the olefinic molecule in the alkyl chain, and that the position of the double bond in the olefin chain determines the point of attachment of the aryl nucleus when the olefin is condensed with an aromatic compound containing a nuclearly replaceable hydrogen atom during the alkylation reaction. The latter conclusion follows from the fact that a hydrogen donor in an alkylation reaction attaches itself to the carbon atom in the olefin chain having the lowest number of hydrogen atoms and accordingly may become bound to either one of the carbon atoms comprising an internal olefinic double bond. Thus, normal dodecene is capable of existing in as many five position isomers, each of which produces a C ce olefin produce aromatic alkylates in which the aryl radical is in the third, fourth or fifth position and that these alkylates when subsequently converted into a detergent product by the attachment of a hydrophilic radical to the alkylaryl portion of the molecule produce optimum surface active agents having the maximum wetting and washing power of any of the alkylated isomers of the normal olefins.
Normal olefins as heretofore indicated are specially desirable for producing alkylates subsequently converted to surface active agents because detergent products in which the alkyl group attached to the aryl nucleus is a relatively straight chain alkyl structure are capable of being biologically degraded during sewage treatment and thus are capable of being finally destroyed when the detergent is eventually discharged into a sewage treatment plant or into a natural stream where it is subjected to anaerobic and aerobic bacterial degradation. In contrast to the detergents prepared from valkylaryl compounds in which the alkyl radicals are of relatively straight chain structure, the corresponding detergents prepared from alkylaryl hydrocarbons in which the alkyl group is of highly branched chain structure (particularly those with quaternary carbon atoms somewhat removed from the aromatic ring) are much more highly resistant to bacterial degradation in sewage treatment and therefore persist in the sewage efiluent and remain active as foaming agents and as surface active agents in streams in which the sewage efiluent containing the detergent is finally disposed. The presence of such agents in streams presents a problem of considerable magnitude to the sewage treatment plants of many cities and to those concerned with the preservation of the natural state of streams and lakes where the bacterially resistant detergent destroys plant life in the body of water in which the bacterially resistant detergent is present and may ultimately destroy fish life also.
Still another nuisance of extreme magnitude associated with biologically resistant or biologically hard detergents is the excessive amount of foam produced'at dam sites and at weirs placed in stream beds to effect aereation is also making itself felt in the contamination of under- 7 ground water sources of supply into which sewage effluent containing the biologically hard detergent enters and contaminates the underground water source. The problem has become manifest to the extent that water drawn from a tap connected to many cities water supply foams noticeably because of its content of biologically hard detergent therein. The normal olefin alkylates of this invention in which the aryl group occupies the third, fourth or fifth position in the alkyl chain of the dodecyl group are not only desirable from the standpoint of being biologically soft to an exceptional degree and thus bacterially degradable in sewage treatment plants, but the detergents prepared from these alkylates also possess optimum surface activity and washing capacity, as compared to other position isomers of the normal olefin series.
One object of this invention is to produce aromatic alkylates 'of a structure capable of yielding biologically soft detergents of the type consisting of the hydrophilic derivative of an arylalkane. Another object of this invention is to produce aryl-substituted alkanes which may be converted into surface active agents having maximum sur: face activity of the possible position isomers formed from a normal olefin utilized as alkylating agent of a aromatic compound.
In one of its embodiments this invention relates to a process for the production of an arylsubstituted alkane in which the alkyl chain of said alkane contains from 9 to about carbon atoms and the aryl group is in one 'of the positions between the third and fifth carbon atoms in the alkyl chain which comprises contacting a normal olefinic hydrocarbon containing from 9 to about 15 carbon atoms with an alkaline isomerization catalyst at isomerizing conditions whereby the normal olefin is converted to a normal olefin in which the double bond is isomerized to a position in the carbon atom chain between the third and fifth carbon atoms from the end of the chain, and alkylating an aromatic compound having a nuclearly replaceable hydrogen atom with the resulting isomerized normal olefin.
As heretofore indicated, the products of this invention which are characterized as alkylates produced from normal olefins and which produce detergents when a suitable hydrophilic radical is substituted on the hydrophobic alkylaryl portion of the molecule are prepared by the so-called process of alkylation in which a normal olefin of specific structure, as hereinafter characterized, is condensed in the presence of an alkylation catalyst with a rnonocyclic aromatic compound containing a replaceable hydrogen atom on the aromatic nucleus which may be selected from benzene and the short chain alkylbenzene as well as phenol, all of which produce suitable hydrophobic groups for the preparation of surface active agents when combined with a suitable hydrophilic radical. Suitable detergents are prepared from the alkylaryl starting materials only when the aryl group is mono-cyclic, only when the alkyl portion of the molecule contains from about 9 to about 15 carbon atoms per alkyl group and only when there is not more than one long chain alkyl group on the aromatic nucleus. Thus, compounds utilizable as starting materials which contain a nuclearly replaceable hydrogen atom are selected from the group consisting of benzene, toluene, xylene, ethylbenzene, and diethylbenzene, as well as phenol, and these when subjected to alkylation in the presence of an acidic alkylation catalyst undergo a condensation in which the nuclearly replaceable hydrogen atom is displaced from the nucleus and permits the attachment of an alkyl radical at the carbon atom of the aryl chain of the olefin containing the double bond, the resulting alkyl radical being a secondary group.
Most sources of the olefinic hydrocarbon alkylating agent utilized to prepare the aromatic alkylate in accordance with the present process occur as mixtures of olefinic hydrocarbon isomers or in admixture with other types of hydrocarbons, such as parafiins, aromatics, etc., and in all probability such isomers are present in admixture with other position isomers of normal olefins in which the olefinic double bond occurs between carbon atoms other than the third and the fourth or the fourth and the fifth carbon atoms in the chain. In order to produce reasonably high yields of the presently desired alkylate products in which the aromatic ring occurs by way of the alkylation reaction on a carbon atom selected from the third to the fifth in the alkyl chain, it is essential that the olefinic fraction utilized as the alkylating agent to form the aromatic alkylate and consisting of the charge stock to the present process be substantially pure, or at least, consist of a predominant proportion of the desired position isomer which, after alkylation and conversion to a detergent, will yield the structure of the detergent product indicated above. The proportion of normal olefins in a particular fraction of hydrocarbons containing olefinic components will in large measure depend upon the source of the hydrocarbon fraction. Thus, a normal olefinic hydrocarbon-containing fraction prepared by dehydrating a normal alcohol with a non-acidic catalyst will contain a relatively large proportion of normal olefins in which the olefinic double bond will occur on the carbon atom formerly containing the hydroxyl group of the alcohol. Similarly, the fraction or cut of the polymers prepared by polymerizing ethylene and boiling in the range in which the components will contain from about a number of carbon atoms within the range of 9 to 15 will also consist substantially entirely of normal olefins, generally normal olefins in which the double bond occurs on the number one carbon atom in the chain. On the other hand, a fraction boiling in the range which yields components containing from C to C carbon atoms and separated from the products of a thermal cracking reaction or a hydrocarbon reformate product will contain not only a variety of double bond position isomers, but also branched chain olefins as well as parafiinic and aromatic hydrocarbons in admixture therewith, although the product formed by thermally cracking a paraffinic wax fraction will consist predominantly of normal olefins. Also, the olefinic product prepared by dehydrogenation of a paraflinic fraction of petroleum or other source of parafiins, especially the product prepared by cracking in the presence of a catalyst containing acidic ions in the structure of the catalyst, will contain a variety of branched chain isomers as well as double bond position isomers of the normal olefin. Thus, in order to prepare a feed stock for the present process containing a predominant, and more preferably, a substantial proportion of normal olefins, it is essential that the normal olefinic containing feed stock be subjected to a separation procedure whereby the normal olefins are concentrated in the product. If the hydrocarbon contaminants are largely parafiinic in nature, one of the preferred means of separating the paraifins from a fraction in a preliminary concentrating step is to contact the initial hydrocarbon mixture with an adsorbent for unsaturated components, such as silica gel, activated carbon, activated alumina or other adsorbent known for its adsorptive capacity for unsaturated compounds. On the other hand, if a considerable proportion of the components present in admixture with the normal olefins are of branched chain structure or of cyclic structure, whether of parafi'inic, olefinic, aromatic or naphthenic character, a separation procedure based upon an adsorbent of the molecular sieve type must be utilized in order to recover the normal olefinic components from admixture with the non-normal compounds, or clathrate formation with urea may be used. Separation of an olefin-containing feed stock prior to the present conversion process from a mixture of hydrocarbons will ordinarily yield a product consisting of normal hydrocarbons in which the olefinic components comprise a mixture of various position isomers of the double bond. The primary requirement of the feed stock utilized herein is that it be a normal hydrocarbon without particular emphasis on the position of the olefinic double bond in the chain of carbon atoms, although normal-l-olefins are an especially preferred charge stock herein. Thus, olefins prepared by the dehydration of normal alcohols with non-acidic catalysts, the desired boiling range fraction of ethylene polymers, and also the olefinic components produced in the cracking of high molecular weight waxes and the hydrogenation of fatty acids also constitute the preferred sources of starting materials in the present process.
The separation and recovery of normal parafiins (from which normal olefins may be prepared directly or indirectly by dehydrogenation) from hydrocarbon fractions comprising a mixture of hydrocarbons, including cyclic and/ or iso-parafiinic hydrocarbons is based upon a method of separation which selectively differentiates between normal and branched chain compounds and between normal and cyclic compounds such as naphthenes and aromatic hydrocarbons and thus requires a molecular sieve type or a ureatype separating process in which the separating agent is selective for the normal components present in the mixture of hydrocarbon isomers. Several molecular sieve type separation procedures are available which have sufficient selectivity to provide product streams containing at least percent of the normal hydrocarbons. One of the preferred separating agents having this degree of selectivity is an inorganic substance characterized by its chemical composition as a dehydrated metal alumino-silicate having a zeolite structure and containing pores of about 5 Angstrom units in cross-sectional diameter which are of sufficient size to permit the entry of parafl'inic orolefinic aliphatic compounds of normal structure, but are not of sufiicient' size to permit the entry of branched chain or cyclic compounds. The metal constituents of these zeolitic compositions are usually selected from the alkaline earth metals, preferably calcium or magnesium which are not only the most effective but also the least expensive of the various alkaline earth metal derivatives. These molecular sieve type sorbents are prepared by the selective crystallization of the metal alumina-silicate from aqueous solutions of water-glass or other suitable source of silica sol, a source of alumina or aluminum hydroxide, and an alkali metal hydroxide the mixture containing certain specific proportions of these oxides, to initially form the alkali metal alumino-silicate from the alkalineearth metal derivative if prepared by subsequent ion-exchange techniques. Thus, sodium alumino-silicate is prepared by combining water, sodium silicate (as water-glass) or a sodium-free silica sol or an alcohol ester of silicic acid such as ethyl ortho silicate, alumina or an alkali metal aluminate and sodium hydroxide in proportions sufiicient to provide the following ratios of reactants, indicated as their oxides:
Na O/SiO 1.0-3.0 SiO /AI O 0.5-1.3 a o/M 35-200 and heating the aqueous mixture at a temperature of from about 40 to about 120 C. for a period up to about 40 hours, or until crystal formation is complete, depending upon the temperature of the reaction. The crystals which precipitate are the sodium form of the metal aluminosilicate and have the following empirical composition:
where M is sodium, if the sodium derivatives are involved hydrated crystals of the alkaline earth metal aluminosilicate are thereafter dried and calcined at temperatures of from 150 to about 500 C. to dehydrate the water of crystallization and thereby develop pores in the aluminosilicate product having the required diameters of about 5 Angstrom units, in which form the product is activated as a molecular sieve for the separation of normal compounds from non-normal isomers or homologues.
Other molecular sieve type separating agents. are also available for recovery of normal parafiins and/ or normal olefins from hydrocarbon mixtures containing the same, including crystalline urea, aqueous solutions of urea which selectively form clathrates with the normal constituents or thiourea which removes the cyclic and branched chain hydrocarbons present in the mixture by'formation of a clathrate therewith, leaving the normal constituents present in the mixture as a rafiinate stream.
In the event that a paraffiuic charge stock is-utilized in the separation stage of the process to recover a normal paraflin from which the present normal olefin may be prepared directly by dehydrogenation of the normal paraffin to the olefin, dehydrogenation of the normal paraffin 'is effected by contacting a stream of the normal parafiin with a dehydrogenation catalyst at reaction conditions generally characterized as dehydrogenation conditions.
For this purpose, the normal paraflins are charged at a temperature of from about 300 to about 450 C. over a catalyst preferably free of acidic constituents and composed of one or more of the neutral or alkaline oxides of the elements of Group VI of the Periodic Table, preferably the oxides of chromium, molybdenum, tungsten and uranium deposited on an inert support, such as alumina, the composite containing from 0.5 percent up to about 30 percent by weight of the Group VI metal oxide and preferably from about 2% to about 20% thereof. Particularly preferred catalytic composites are the calcined alumina chromia compositions containing from Sto about 12 percent by Weight of chrom ia andalumina-molybdena composites containing from 2 to about 20 percent by weight of molybdena. In order to reduce the tendency of the paraflinic feed stock and/or olefinic product to undergo isomerization by eliminating the possibility of acidic ions being present in the catalyst, the latter may be composited with from about 1 to about 10 percent by weight of an alkali metal oxide such as potassium or lithium oxide to maintain the alkalinity of the catalyst. Dehydrogenation of the normal parafilns proceeds at temperatures of from about 350 to about 600 C. and at relatively low pressures, preferably in the region of atmospheric and at short contact times between the charge stock and catalyst. Generally, the conversion of the normal parafiins contained in the charge stock tothemonoolefin analogs corresponding thereto does not go to completion in a once-through passage of the charge stock through the catalyst bed and in order to increase the concentration of mono-olefin in the dehydrogenation reaction product, it is usually preferred to separate the monoolefin from the unconverted normal paraffins and recycle the latter to the dehydrogenation zone. The separation of the mono-olefins formed in the dehydrogenation reaction from the unconverted paraflins is effected by passing the reaction product in liquid phase through a bed of a suitable adsorbent which selectively retains the olefins on the surface of the adsorbent without adsorbing the normal paraffins. Suitable adsorbents of this type include silica gel particles, activated charcoal (such as cocoanut shell char) activated alumina (such as calcined bauxite) and others.
Indirect dehydrogenation may be effected by wellknown chemical means, for example, by mono-chlorination and subsequent dehydrochlorination. The normal olefins which comprise one of the primary feed stocks in the present process and which determine the structure of the resulting alkylate product of this invention by virtue of the position of the double bond in the olefin chain, either separated as the olefinic product of a normal parafiin dehydrogenationreaction or prepared by any of the foregoing methods of production, are isomen'zed to olefins containing the double bond in a position on the carbon atom chain between the third and fifth carbon atoms by means of an isomerizaition reaction effected in the presence of an alkaline catalyst which is especially effective in producing the desired position isomers without affecting isomerization of the normal olefins to branched chain and cyclic isomers.
In accordance with the. process of the present invention, n-olefins containing the olefini-c double bond in the 1, 2, 5, 6, or 7 positions (where the chain size permits such position) are converted via isomerization to their olefin isomers containing the olefinic double bond in the third to the fifth position which, as heretofore indicated, yield aromatic hydrocarbon alkylates capable of being converted to detergent products having especially favorable detergency and other surface active properties. Thus, C normal olefin is capable of existing in four isomeric normal olefin modifications in which the double bond is capable of existing in the olefin chain in four different positions, the C and C normal olefins are capable of existing in five isomeric position modifications, the (.2 and C olefins'are capable of existing in six isomeric position modifications and the C and C olefins are capable of existing in seven isomeric position modifications. C to C normalolefin fractionboiling from about to about 225 C. probably contains at least some of each of the various position isomers and may therefore contain a total of 40 diiferent position isomers.
Isomerization of normal olefins to form the position isomers in which the double bond is located on a carbon atom between the third and fifth carbon atoms in the olefin chain is effected by contacting the normal olefin in the liquid phase with a particular type of catalyst herein characterized as an alakline catalyst comprising one of the alkali metals, an oxide thereof, an hydroxide of the alkali metal or an amide derivative thereof on a suitable, substantially inert support. In the presence of these catalysts which will be hereinafter more specifically characterized, the isomerization of normal olefins to the aforementioned selective isomers is eifected at temperatures of from about 50 to about 300 C. and at a pressure sufficient to maintain the normal olefin substantially in liquid phase, which at the above-mentioned conversion temperatures may require pressures up to about 30 atmospheres. The residence time of the feed stock with the catalyst at the above conversion condition is a critical factor essential to the realization of reasonable yields of the desired mono-olefin isomers. Suitable contact periods of the mono-olefin with the catalyst are provided by liquid hourly space velocities which may range, for example, from about 0.5 to about 2.5 volumes of liquid feed stock per volume of catalyst per hour. In order to increase the conversion of the olefin feed stock to the desired normal olefin isomer, to minimize side reactions such as polymerization, and to provide the desired rapid rate of throughput of the feed stock through the catalyst reaction zone, the normal olefin feed stock may be diluted with from 2 to l to about 10 to 1 volumes of a lower boiling normal paraffin such as normal pentane or normal hexane which may be readily separated from the reaction mixture following the isomerization reaction by distillation of the diluent from the reaction mixture after passage of the charge stock through the isomerization zone. Although the present conversion of the normal olefin charge stock to the desired isomer is an equilibrium reaction, the presence of the normal paraffin diluent in the feed stock enhances the yield of the desired isomers.
Suitable alkaline isomerization catalysts for effecting the above indicated isomerization in accordance with the process of this invention, includes one or more of the various alkali metals (that is, the left-hand column of elements of Group I of the Periodic Table), their oxides, hydroxides and amides, preferably supported on a relatively inert base, such as alumina, charcoal, fire-brick or any of the various non-acidic, porous refractory metal oxides which retain the alkaline material within the body of the support without being removed in the flowing stream of fluid charge stock. Thus, sodium, potassium or lithium may be mixed with a porous alumina support and utilized as such for the catalyst of this process or these alkali metals may be converted to their oxides which are more readily supported by a porous support. The amount of alkali metal or oxide on the support may range from 0.5 percent to about 50 percent by Weight, although quantities within the range of from about 2 percent to about percent are generally sufficient for this purpose. The hydroxides of the alkali metals, such as lithium hydroxide, sodium hydroxide, or potassium hydroxide may be added as an aqueous solution to the inert support and the mixture evaporated to dryness until substantially free from moisture. Another, generally preferred method, of preparing an alkali metal oxide supported catalyst comprises mixing a suitable porous, refractory support with an aqueous solution of a nitrate or nitrite salt of the alkali metal, evaporating the mixture to dryness and thereafter heating the resulting composite to a temperaure at which the alkali metal salt decomposes, leaving deposited the alkali metal oxide. One of the preferred alkali metal oxide catalysts of this type is lithium oxide supported by alumina and containing from 1 percent to about percent by weight of lithium oxide. Another preferred class of alkaline catalysts utilizable herein are the supported alkali metal amides, prepared 'by mixing the alkali metal amide, such as sodarnide with a porous, refractory supporting material in an anhydrous atmosphere, pressing the mixture into conveniently sized pellets and thereafter calcining the resulting pellets at a temperature of about 150 to form the finished catalyst particle. Other methods of preparing the alkaline catalyst and other catalysts of this type are well-known in the prior art and may be utilized in the present process to provide the source of alkaline isomerization catalyst utilized in this process.
Following the isomerization of the normal olefins to the desired position isomers in which the double bond occupies a carbon atom between the third and fifth carbon atoms in the normal olefin chain, the isomerized normal olefin product is utilized as an alkylating agent for condensation with an alkylatable, mono-cyclic aromatic compound selected from the group consisting of benzene, toluene, xylene, ethylbenzene, methylethylbenzene, diethylbenzene and phenol, yielding a mono-alkylate which is the desired end product of the present process. The alkylation reaction is preferably effected in the presence of a suitable catalyst capable of promoting the condensation reaction, generally an inorganic material characterized as an acid-acting compound which catalyzes the alkyl addition reaction involved in the process. Acid-acting inorganic compounds which are active alkylation catalysts in the present condensation or alkylation reaction include certain mineral acids, such as sulfuric acid containing not more than about 15 percent by weight of water and preferably less than about 8 percent by weight of water, including used sulfuric acid catalysts recovered from the alkylation of isoparafiins with mono-olefins; hydrofluoric acid of at least percent concentration and containing less than about 10 percent by weight of water; liquefied anhydrous hydrogen fluoride; anhydrous aluminum chloride or aluminum bromide; boron trifluoride, preferably utilized in admixture with concentrated hydrofluoric acid; and other acid-acting catalysts, particularly others of the Friedel-Crafts metal halide class. The catalyst especially preferred herein for the present alkylation reaction is hydrogen fluoride containing 5 percent or less of water. Sulfuric acid of at least percent concentration, up to percent, is also a preferred catalyst. In the process of condensing the aromatic reactant with the normal olefin, the hydrogen fluoride, for example, in liquid phase and the aromatic compound are charged into a stirred pressure autoclave, followed by the addition to the stirred mixture of the mono-olefinic hydrocarbon, the resulting mixture being thereafter maintained as stirring continues at a temperature of from about 20 to about 30 C. In order to maximize the production of alkylate from the mono-olefin charged to the process, it is generally preferred that the molar ratio of aromatic compound to the olefin reactant charged into the alkylation reaction be greater than 1 to l, more preferably within the range of 2 to l to about 15 to 1 mols of aromatic per mol of olefin. The efiluent mixture is separated to recover the organic portion of the reaction efiiuent from the used catalyst, the organic mixture thereafter being fractionated to recover the excess aromatic hydrocarbon from the residue of alkylaromatic product which remains in the distillation zone as a higher boiling residue. In most instances, when the molar proportion of the aromatic to mono-olefin charged to the process exceeds 1 to 1 and more desirably ranges from about 5 to 1 to about 10 to 1, the mono-olefin is more or less completely consumed during the condensation reaction and the desired mono-alkylate, rather than a polyalkyl-substituted aromatic alkylate, is obtained as the principal product of the process.
The alkylate obtained by one of the aforementioned condensation reactions constitutes the raw material or starting stock for the preparation of the utirnate detergent or surface active product. Thus, a highly effective detergent is prepared from the alkylate by sulfonation which isomerization catalyst at isomerizing' conditions.
thereafter calcined at 500 C. for four hours. resulting pills which are hygroscopic contain approxproduces the mono-sulfonic acid derivative, followed by neutralization with a salt-forming base, such as sodium hydroxide, to :form a water-soluble alkylaryl sulfonate detergent. The alkylate may also be nitrated to form a nuclearly-substituted mono-nitro derivative which is catalytically reduced to the mono-amino-substituted analog. This amine is thereafter condensed with ethylene oxide 1 or propylene oxide to form the corresponding polyoxyalkylated detergent product, preferably containing from 10 to about 20 oxyethylene units. In the case of the phenol alkylates, these are converted directly to detergent products by way of oxyalkylation with ethylene or propylene oxide (preferably ethylene oxide) until the product contains from 6 to about 15 oxyethylene units per molecule.
. The present invention is further described in the following illustrative examples, which, however, are not presented for the purpose of limiting the scope of the invention, but for purposes of illustrating several of its embodiments.
In the following series of runs, three sources of olefinic hydrocarbons, each consisting predominantly of C olefins are compared to determine the effectiveness of their respective benzene alkylates as charge stocks for conversion to detergents in the form of their sodium sulfonate derivatives. The following dodecenes, each capable of producing an alkylate of different structure are utilized in the comparative runs:
(1) Normal dodecene-1.
(2) Normal dodecene-l isomerized to isomers in which the double bond occupies a position between the 3rd and 5th carbon atom in the chain.
(3) Propylene tetramer in which the component C olefins are branched chain structure. 1
A substantially pure sample of dodecene-l is prepared by chemical dehydration of lauryl alcohol (primary normal dodecanol). For this purpose lauryl alcohol is passed through a column of non-acidic activated alumina approximately 36 inches in length at a temperature of 300 C. and at aspace velocity of 0.5 volumes of liquid alcohol per volume of alumina per hour. The dodecene product is removed from the product outlet at the bottom of the column and analysis indicates that over 95 percent of the dehydration product recovered is dodecene-1.
Sample 2 of the dodecene charge stock is prepared by isomerization of dodecene-1 in accordance with this invention by passing dodecene-1 isomer over an alkaline The catalyst utilized for this purpose is lithiated alumina containing potassium amide. The alumina support is prepared by' precipitating aluminum hydroxide from an aqueous solution of alumintun chloride by the addition thereto of ammonium hydroxide, the precipitate is Washed free of chloride ions and thereafter dried at 120 C. for four hours, followed by calcination at 450 C. for three hours.
The resultingalurnina is thereafter thoroughly mixed with an 0.125 percent aqueous solution of lithium nitrate, utilizing 400 cc. of solution per 100 grams of alumina.
.The paste is then extruded into pellets'of /s inch by Ms inch size, whichare dried at 120 C. for six hours and The imately 0. percent by weight of Li O. These are then impregnated with a liquid ammonia solution of potassium amide and the excess ammonia then evaporated to leave 7 a final catalyst containing 18% of KNH length and contains the catalyst on an internal wire screen support. The dodecene-n-hexane mixture is passed through the catalyst-packed reactor at a pressure of 200 lbs./in. at a temperature of 480 C. and at a liquid hourly space velocity of 1.5 volumes of charge mixture (0.15 volume of dodecene) per volume of catalyst per hour. The efiluent mixture is separated by distillation to recover the dodecene isomate. Analysis of the product by infrared spectral and chromatographic methods indicates that less than 10 percent of the dodecene-1 charged is recovered as dodecene-1 and that 72 percent of the product consists of position isomers in which the olefinic double bond occupies a position between the third and fifth carbon atoms in the dodecene chain.
The third source of dodecene which is composed of a variety .of branched chain isomers and various double bond position isomers is prepared by polymerization of propylene over a solid phosphoric acid catalyst (a composite of pyrophosphoric acid and kieselguhr containing approximately percent by Weight of pyrophosphoric acid, calcined at a temperature of 550 C.). A mixture of propylene-propane is charged at lbs/in. and at 350 F. over the catalyst and the liquid product separately collected and distilled to recover a fraction boiling from to 225 C. The latter fraction consists of 93 percent by weight of dodecenes.
The olefinic fractions as prepared by the above procedures are each then separately mixed with 10 molar proportions of benzene, based upon the average molecular weight of the olefins as 168 (dodecene) and the hydrocarbon mixture cooled to 0 C. as enough hydrofluoric acid of 98.5 percent concentration is added (with stirring) to provide a weight ratio of acid to olefins of 1.5. The mixture is maintained within the temperature range of from 0 to 10 C. during a period of one hour, after which the mixture is allowed to settle and the lower acid layer withdrawn from the upper hydrocarbon layer. The hy-' drocarbon phase is washed with dilute caustic to remove dissolved hydrogen fluoride and then distilled to remove excess benzene and a small quantity of aliphatic hydrocarbons boiling in the mono-olefin range.
The benzene alkylate product prepared from dodecene-1 of the following formula:
The benzene alkylate product produced by alkylation of benzene with-the isomerized dodecene-1 in whichto a large extent-the double bond in the dodecene chain occupies a position between the third and fifth carbon The isomerization of dodecene-1 is eflected by passing 7 weight dodecene-1) through-aheated isomerization zone containing the above supported Li O-KNH catalyst. The isomerization reactor is a tube approximately Z-inches inside diameterheated by a thermostatically controlled electrical resistance wire wound around the tube and insulated. The reaction zone of the tube is 26 inches in a mixture of dodecene-1 Withn-hexane (10 percent by atoms in the series and having the following predominant structure:
wherein R is from 2 to 4 carbon atoms in chain length and R is from 9 to 7 carbon atoms in chain length is produced in a yield of 86 percent, based upon the olefin charge. I
The benzene alkylate product produced by alkylation of benzene with propylene tetramer has a structure corresponding to the .alkylbenzene represented by the followingystructural formula: v
wherein R R and R represent alkyl groups totaling 11 carbon atoms, is produced in a yield of 78 percent by weight, based upon the olefin charge.
Each of the above alkylates prepared as indicated above are sulfonated by mixing the alkylate with an equal volume of liquefied normal butane and then with 30 percent oleum added to the diluted alkylate mixture as a small stream flowing onto the chilled surface of a rotating cylinder. The surface of the cylinder is cooled by circulating salt water cooled to 10 C. on the inside of the cylinder as the latter is rotated. The reactants on the cylinder surface are scraped and the mixture re-spread on the surface of the cylinder by a steel blade, the normal butane evaporating into a hood as the heat of reaction raises the temperature and boils off the butane, thereby maintaining the temperature at or near C.
Each of the above sulfonation reaction mixtures is diluted by mixing with ice and thereafter the acids are neutralized to a pH of 7 with sodium hydroxide. The products from the three sources of alkylates are light cream colored solids which are highly soluble in water. The evaporated solids are extracted with 95 percent ethanol to recover sodium sulfate-free products and the latter are thereafter mixed with sufficient sodium sulfate builder salt to provide detergent compositions containing a 60-40 weight ratio of sodium alkylaryl sulfonate and sodium sulfate. Each sample of detergent product-sodium sulfate composition is then tested for deter'gency in a standard Launder-O-Meter test procedure in which cotton muslin swatches are soiled with a synthetic soil composition consisting of vegetable oil containing oil-dag (a graphite-mineral oil suspension), and the swatches thereafter washed with a 0.3% aqueous solution of the detergent at 140 F. in the Launder-O-Meter. The effectiveness of each of the detergentvsarnples is measured by determining the reflectance of white light from the surface of the laundered swatches and comparing the reflectances. The average reflectance-of the swatches laundered in a 0.3% solution of the detergent made from propylene tetramer-benzene alkylate is taken as a standard, and given the relative value of 100. The following Table I presents the results of the Launder-O-Meter test for each of the detergent samples compared by the above procedure, as well as data on solubilities and wetting power:
Comparison of detergency of alkylated benzene sulfonate prepared from (1) dodecene-J, (2) isomerized dudecene-l, and (3) propylene tetramer z Samples of each of the detergents prepared from the various dodecene isomers are separately subjected to simulated sewage treatment conditions in order to determine the relative rates and extent of removal of each composition. A 0.3 percent aqueous solution of each of the'above detergents gallons each) is prepared and to each of the solutions 0.5 lb. of urea (to supply nitro gen nutrient), 0.2 lb. of sodium sulfate (to supply -SO nutrient), 0.2 lb. of potassium phosphate (to supply -PO nutrient) and trace quantities of zinc, iron, magnesium, manganese, copper, calcium and cobalt are added to provide the necessary nutritional requirements of the bacteria added to each of the solutions in the form of 1 lb. of activated sewage sludge supplied from a sewage treatment plant. The simulated sewage composition placed in a large circular tank is thereafter stirred as air is introduced into the bottom of the tank in the form of fine bubbles through fritted glass nozzles. Approximately 50 cc. samples of the sewage suspension are removed from each of the tanks at three-hour intervals after an initial digestion of twenty-four hours, filtered, and equal quantities of the filtrate (50 cc.) measured into shaker bottles to determine the height of foam produced after shaking each of the samples of filtrate under similar test conditions, the level of foam providing an approximation of the quantity of detergent remaining in solution after sewage digestion. 50 cc. samples of each of the initial, non-digested detergent solutions, shaken for 10 minutes in the test apparatus produced essentially equal volumes of foam, 15 cm. in height. The results of foam height determinations for each of the solutions sampled thereafter, an empirical measure of the amount of detergent remaining in solution, are presented in the following Table II for each of the samples:
TABLE II Quantity of foam produced from 50 cc. samples of sewage solution at various intervals of sewage treatment time Foam Height, Cm. Time of n-Dode- Sample No. Treatcone-1 ment, Hrs. Alkylate Isomerized Propylene n-Dodeeene Tetramer Alkylate Alkylate 0 15 15 15 24+3 13 12 14 24+6 12 11. 5 14 24-1-9 10 9 v 13. 5 24+12 8 7 I3 24+15 7 6 13 24+18 G 4 12. 5 24+24 5 3 11.5 484-6 4 2 11 48+12 2 1 10. 5 48+24 1 1 10 The sample of detergent prepared from the branched chain (tetramer) alkylate remains active (i.e., produced foam) even after 108 hours.
I claim as my invention:
1. A process for the production of an improved detergent from r (a) an aromatic compound selected from the group consisting of benzene, toluene, xylene, ethylbenzene,
methylethylbenzene, diethylbenzene and phenol, and (b) a normal mono-olefin of from 9 to about 15 carbon atoms per molecule in which the double bond is in a position other than the 3- and 4-positions, which comprises (1) isomerizing said olefin in contact with an alkaline isomerization catalyst selected from the group consisting of alkali metals and their oxides, hydroxides and amides at a'temperature of from about 50 to about 300? C. and a pressure sufiicientto maintain the olefin substantially in liquid phase to convert the same to a normal olefin isomer in which the double bond is in a position between the third and fifth carbon atoms of the chain,
' 13 (2) alky lating said aromatic compound with said isomer in contact with an acid-acting alkylation catalyst at a temperature sufficient to form an arylsubstituted alkane in which the aryl radical is attached to a carbon atom from the third to the fifth carbon atom of the alkyl chain, and
(3) sulfonating the resultant alkylate.
2. The process of claim 1 further characterized in that the aikylatingstep (2) is performed at a temperature of from about 20 to about 30 C.
3. The process ofclairn 1 further characterized in that said normal olefin is dodecene 4. The process of claim 1 fiurther characterized in that said aromatic compound is benzene.
5. The process of claim 1 further characterized in that said alkaline isomerization catalyst is supported on a refractory, substantially inent support.
6. The process of claim 5 further'charaoterized in that said alkaline isomerization catalyst is lithium oxide.
' 7. The process of claim 5 further characterized in that said alkaline isomerization catalyst is potassium amide.
1 4 References Cited in the file of this patent UNITED STATES PATENTS 2,233,408 Flett Mar. 4, 1941 2,467,130 Hunt et a1. Apr. 12, 1949 2,467,132 Hunt et a1. Apr. 12, 1949 2,740,820 Wilson et a1. Apr. 3, 1956 2,806,875 Geiser Sept. 17, 1957 2,952,719 Appell Sept. 13, 1960 2,988,578 Fleck et a1. June 13, 1961 3,009,972 Johnson Nov. 21, 1961 OTHER REFERENCES McCutcheon: Synthetic Detergents, 1950, p. 191, TP
Baumgartner: Ind. and Eng. Chem, vol. 46, June 1954, pp. 1349-1352, TPLASS.
Hammerton: J. Appl. Chem, vol. 5, September. 1955, pp. 517-524, TP1J91.
Sawyer et al.: Ind. and Eng. Chem, vol. 48, February 1956, pp. 236-249, TP1A58.