LINEAR ALKYLBENZENE FORMATION USING LOW TEMPERATURE IONIC LIQUID AND LONG CHAIN ALKYLATING AGENT

Abstract: Linear alkylbenzene compositions can be made by using, as a catalyst, a low temperature molten ionic liquid composition comprising a mixture of a metal halide and a base and, as the alkylating agent for the benzene reagent, a chloroalkane having an average carbon atom content of more than six, an olefin having an average carbon atom content of more than ten, or a mixture of the chloroalkane and the olefin. A novel ionic liquid, which is also useful in other reactions normally catalyzed by previously known ionic liquids, comprises the reaction product of a metal halide, such as aluminum trichloride, and an alkyl-containing amine hydrohalide salt selected from the group consisting of a monoalkyl-, a dialkyl-, a trialkyl-containing amine hydrohalide salt (such as trimethylamine hydrochloride), and mixtures thereof.

Description: LINEAR ALKYLBENZENE FORMATION USING LOW TEMPERATURE IONIC LIQUID AND LONG CHAIN ALKYIATING AGENT BACKGROUND OF THE INVENTION This invention, in one embodiment thereof, relates to the catalytic alkylation of an aromatic molecule with a suitable long chain alkylating reagent (e.g., an olefin that has an average carbon content of over C ι0 , such as a Cn to C14 olefin or a halogenated alkane that is larger than C 6 , such as a C B to Cn olefin) using, as a novel type of catalyst, an ionic liquid catalyst composition which is molten at low temperatures. The term "linear alkylbenzene formation" as used herein is intended to cover the process by which such higher alkyl moieties are placed on benzene compounds, with the term "alkyl" being intended to cover the conventional paraffinic alkane substituents, "higher" being intended to mean C 6 or longer if a linear chloroalkane is used as the alkylating agent and higher than Cio if an olefin is used as the alkylating agent, and the term "benzene" is intended to include both unsubstituted as well as substituted (e.g., lower alkyl substituted) benzene compounds. As is well known in the art, this type of alkylation process is now conventionally practiced by the catalytic reaction of an unsubstituted or lower alkyl-substituted benzene compound with a higher alkene or a halo-substituted higher alkane, such as a chloro-substituted higher alkane using a differing type of catalyst from that utilized herein, namely either hydrogen fluoride or aluminum trichloride. J.A. Boon et al . , Journal of Organic Chemistry, 1986, 51, 480-483 describe several laboratory scale syntheses where benzene is alkylated using an imidazolium ionic liquid catalyst with four differing linear chloroalkane alkylating agents that contain only up to four carbon atoms and an additional run using cyclohexylchloride as the alkylating agent. As earlier indicated, in commercial practice, the alkylating agent is a long chain alkene or halogenated alkane, such as dodecene or dodecylchloride, using differing classes of catalyst from that described herein. Recent patents which illustrate an alkylation reaction of this type include U.S. Patent Nos. 5,196,574 to J.A. Kocal and 5,386,072 to P. Cozzi et al . A recent publication discussing this reaction is contained in INFORM, Vol. 8, No. 1 (Jan. 1997), pp. 19-24. SUMMARY OF THE INVENTION This invention, in one embodiment, relates to linear alkylbenzene formation using, as the catalyst, a low temperature molten composition or "ionic liquid" and, as the alkylating agent in the process, an olefin having an average carbon content of over 10, a chloroalkane having an average carbon content of over 6, or mixture thereof. Another embodiment is a novel class of alkyl- containing amine hydrohalide ionic liquid compositions that are formed by a novel reaction. These ionic liquid catalysts are useable in the previously described novel linear alkylbenzene process as well as being useable in conventional alkylbenzene formation processes as well as other chemical reactions which utilize an ionic liquid as a catalyst. DETAILED DESCRIPTION OF THE INVENTION The general class of ionic liquids which is of special interest to this invention, as a novel catalyst class for use therein, is the class of fused salt compositions which are molten at low temperature. Such compositions are mixtures of components which are liquid at temperatures below the individual melting points of the components. The mixtures can form molten compositions simultaneously upon contacting the components together, or after heating and subsequent cooling. Examples of conventional low temperature ionic liquids or molten fused salts, which may be used herein in the embodiment of the alkylation process for forming linear alkylbenzene compositions which uses long chain alkylating agents, are the chloroaluminate salts discussed by J. S. ilkes, et al., J. Inorg. Chem. , Vol. 21, 1263-1264. Alkyl imidazolium or pyridinium salts, for example, can be mixed with aluminum trichloride (A1C1 3 ) to form such fused chloroaluminate salts. Also, chlorogallate salts made from gallium trichloride and methylethyl-imidazolium chloride are discussed in Wicelinski et al . , "Low Temperature Chlorogallate Molten Salt Systems," J. Electrochemical Soc. , Vol. 134, 262- 263, 1987. The use of the fused salts of 1- alkylpyridinium chloride and aluminum trichloride as electrolytes are discussed in U.S. Pat. No. 4,122,245. Other patents which discuss the use of fused salts from aluminum trichloride and alkylimidazolium halides as electrolytes are U.S. Pat. Nos. 4,463,071 and 4,463,072 and British Patent No. 2,150,740. U.S. Patent No. 4,764,440 to S.D. Jones describes ionic liquids which comprise a mixture of a metal halide, such as aluminum trichloride, and what is termed a "hydrocarbyl-saturated onium salt", such as trimethylphenylammonium chloride. In such ionic liquids, the onium salt component, if based on the presence of a nitrogen atom, is fully saturated wit four substituent groups . U.S. Patent No. 5,104,840 to Y. Chauvin et al . describes ionic liquids which comprise at least one alkylaluminum dihalide and at least one quaternary ammonium halide and/or at least one quaternary ammonium phosphonium halide; and their uses as solvents in catalytic reactions . PCT International Patent Publication No. WO 95/21872 describes ternary ionic liquids which can comprise a metal halide, such as aluminum trichloride, an imidazolium or pyridinium halide, and a hydrocarbyl substituted quaternary ammonium halide or a hydrocarbyl substituted phosphonium halide. See page 4, lines 18-24 for the description of the hydrocarbyl substituted quaternary ammonium halide. The metal halides useful in forming the desired ionic liquid catalyst intended for use in the present process are those compounds which can form anions containing polyatomic chloride bridges in the presence of the alkyl-containing amine hydrohalide salt. Preferred metal halides are covalently bonded metal halides. Suitable metals which can be selected for use herein include those from Groups VIII and IB, IIB and IIIA of the Periodic Table of the Elements. Especially preferred metals are selected from the group comprising aluminum, gallium, iron, copper, zinc, and indium, with aluminum being most preferred. The corresponding most preferred halide is chloride and therefore, the most preferred metal halide is aluminum trichloride. Other possible choices for metal halides to select include those of copper (e.g. , copper monochloride) , iron (e.g. , ferric trichloride) , and zinc (e.g. , zinc dichloride) . Aluminum trichloride is most preferred because it is readily available and can form the polynuclear ion having the formula A1 2 C1 7 ~ . Furthermore, the molten compositions comprising this polynuclear ion are useful as described hereinbefore. Mixtures of more than one of these metal halides can be used. Granular (+4 -14 mesh) aluminum trichloride is an especially preferred metal halide to employ. It is easy to handle in air without fuming problems and has good flow properties. Its reaction with trimethylamine hydrochloride, for example, is slower and more uniform than with aluminum trichloride powder, with a temperature exotherm to about 150°C. While the resulting ionic liquid is slightly hazy due to the presence of insoluble impurities from the aluminum trichloride, the insoluble, which settle out upon storage of the liquid, do not have an adverse effect on the catalytic performance of the ionic liquid in regard to the process of the present invention. The alkylation reaction of the present invention in which the previously described long chain alkylating agents are employed can be practiced using a know ionic liquid catalyst (for example, one which utilizes as its base component a quaternary ammonium salt, an imidazoline or alkyl-substituted imidazoline salt, a pyridinium or alkyl-substituted pyridinium salt, a sulfonium or alkyl- substituted sulfonium salt, or a phosphonium or alkyl- substituted phosphonium salt) . While it is within the contemplation of the embodiment of the present invention which relates to the use of a long chain alkylating agent in linear alkylbenzene formation to employ any of the known classes of ionic liquid catalysts, such as previously described, it would be desirable to utilize fused salt compositions which are not difficult to prepare and which would be formed using relatively low cost components as compared to some of the ionic liquids of the prior art. Thus, one especially preferred class of ionic liquid is based upon the use of an alkyl-containing amine hydrohalide salt as the base component for the ionic liquid. The terminology "alkyl-containing amine hydrohalide salt", as used herein, is intended to cover monoamines, as well as diamines, triamines, oligoamines and cyclic amines which comprises one or more "alkyl" groups and a hydrohalide anion. The term "alkyl" is intended to cover not only conventional straight and branched alkyl groups of the formula -(CH 2 )„CH 3 where n is from 0 to about 29, preferably 0 to about 17, in particular 0 to 3, but other structures containing heteroatoms (such as oxygen, sulfur, silicon, phosphorus, or nitrogen) . Such groups can carry substituents. Representative structures include ethylenediamine, ethylenetriamine, morpholino, and poloxyalkyl mine substituents. "Alkyl" includes "cycloalkyl" as well. The preferred alkyl-containing amine hydrohalide salts useful in this invention have at least one alkyl substituent and can contain as many as three alkyl substituents. The preferred compounds that are contemplated herein have the generic formula R 3 N.HX, where at least one of the "R" groups is alkyl, preferably alkyl of from one to eight carbon atoms (most preferably, lower alkyl of from one to four carbon atoms) and X is halogen, preferably chloride. If each of the three R groups is designated R x , R 2 and R 3/ respectively, the following possibilities exist in certain embodiments: each of R1-R3 can be lower alkyl optionally interrupted with nitrogen or oxygen or substituted, for example, with aryl ; Ri and R 2 can form a ring with R 3 being as previously described for Ri; R 2 and R 3 can either be hydrogen with R_ being as previously described; or R 1; R 2 and R 3 can form a bicyclic ring. Most preferably, these groups are methyl or ethyl groups. If desired the di- and trialkyl species can be used. The alkyl groups can be substituted with other groups which will not interfere with the desired catalytic reaction. However, such further substitution may undesirably increase the size of the group, and correspondingly increase the viscosity of the melt. Therefore, it is highly desirable that the alkyl groups be comprised of carbon and hydrogen groups, exclusively. Such short chains are preferred because they form the least viscous or the most conductive melts. Mixtures of these alkyl-containing amine hydrohalide salts can be used. The mole ratio of alkyl-containing amine hydrohalide salt to metal halide can, in general, range from about 1:1 to about 1:2.5. In a highly preferred embodiment, the low temperature molten composition useful as a catalyst in this invention consists essentially of the metal halide and the alkyl-containing amine hydrohalide salt. Specifically, the most preferred low temperature molten composition is a mixture consisting essentially of a mole ratio of trimethy1 mine hydrochloride to aluminum trichloride of from about 1:1.5 to about 1:2, preferably about 1:2. Typically, the metal halide and the alkyl-containing amine hydrohalide salt are solids at low temperature, i.e., below about 100° C. at standard pressure. After mixing the two solids together, the mixture can be heated until the mixture becomes a liquid. Alternatively, the heat generated by the addition of the two solids will result in forming a liquid without the need for additional external heating. Upon cooling, the mixture remains a liquid at low temperature, i.e., below about 100°C, preferably below about 60°C, and more preferably below about 30°C. In regard to the previously described and most preferred class of ionic liquid, another aspect of the present invention is the novelty per se, as compositions of matter, of the monoalkyl, dialkyl, and trialkyl species in the previously described class of alkyl- containing amine hydrohalide salt-containing ionic liquid as compared to the most similar type of ionic liquid described in European Patent Publication No. 576,323. This patent contains various teachings in regard to amine hydrohalide-containing ionic liquid catalysts (for the alkylation of aliphatic, rather than aromatic, hydrocarbons) without actually demonstrating that the novel compositions shown and claimed herein can actually be readily made (see the comparative Example provided hereinbelow) . Moreover, the novel amine hydrohalide- containing ionic liquid catalysts described herein are deemed to be novel in regard to their general use in a linear alkylbenzene alkylation apart from the novel embodiment, applicable to also be used with known ionic liquid catalysts, where a long chain alkylation agent is used. The linear alkylbenzene alkylation processes of the present invention have a number of advantages as compared to the conventional manner in which linear alkylbenzenes are synthesized in commercial practice. For example, while the use of aluminum chloride, as the catalyst, at a desirable catalyst/olefin mole ratio (for example, about 0.12) , will yield a product having a desirable content for a liquid detergent composition (greater than about 30%) of 2-dodecyl benzene, the process involves solid materials handling, and an undesired sludge by-product is formed. The present invention uses a similar catalyst/olefin ratio, does not involve solid materials handling, and does not form an undesired sludge byproduct. The use of hydrogen fluoride, as the catalyst, at a much higher catalyst/olefin ratio (about 5 - 20) , while not causing a sludge problem or requiring solid materials handling and while being intermediate in regard to its dialkyl benzene impurity level (about 2% or less) , results in an inferior content for a liquid detergent composition (about 20%) of 2-dodecγl benzene. The following isomer distribution (weight % of dodecylbenzene from the reaction of 1-dodecene and benzene) was reported for the two known catalyst systems, which are not ionic liquids, described below: Catalyst System Isomers HF AlCl ^ 1-dodecylbenzene 0 0 2-dodeσylbenzene 20 32 3-dodecylbenzene 17 22 4-dodecylbenzene 16 16 5-dodecylbenzene 23 15 6-dodecylbenzene 24 15 The ionic liquid of the present invention is both easily recyclable while the standard HF catalyst that is employed, which has similar features, has recognized environmental shortcomings and needs to be used in higher amounts (a 5 to 20 catalyst/olefin mole ratio) than the present catalyst (about a 0.004 or higher catalyst/olefin mole ratio is generally needed) . The present catalyst is a liquid, unlike aluminum trichloride which forms a sludge by-product may be difficult to recycle. It has been found that the presence of water in the benzene reagent used in the practice of the present invention as well as the composition of the ionic liquid invention as well as the composition of the ionic liquid (for example, either 1:2 or 1:1.5 trimethylammonium chloride : aluminum trichloride) does not have a significant effect on the alkylation reaction of this invention. Higher benzene to olefin (dodecene) mole ratios (for example, 12/1 rather than 8/1) produce a higher selectivity to the desired monoalkylbenzene product (namely, 90% versus 80%) . Dilution of the reaction medium with paraffins (for example, a threefold dilution) produces a low reaction rate and a low selectivity (for example, 78%) to the desired monoalkylbenzene product. Besides using the conventional alkylating reagents previously mentioned (e.g. , a C 4 to Cn olefin or a halogenated alkane of similar chain length) in the process of the present invention, this invention contemplates the possible presence of functional groups , such as cyano or halo, on the alkylating agent (e.g., an olefin) . In selecting the desired functional group, the chosen group should not be one which will react with the ionic liquid under the particular process conditions used. For example, such groups as hydroxy, amino, and carboxy have been found to react with a metal halide, such as aluminum chloride, under certain process conditions. The following Examples are illustrations and not limitations of the invention. COMPARATIVE EXAMPLE This initial Example is intended to describe an attempt that was made to easily form an ionic liquid from aluminum trichloride and pyridine hydrochloride as described in an Example in European Patent Publication No. 576,323. Aluminum trichloride (24.7 g) was added to about 50 ml of heptane in a flask equipped with a mechanical stirrer to form a suspension, and then pyridine hydrochloride (11.56 g) was added to this suspension. The resulting solid portion of the suspension turned brown as the reaction proceeded slowly. After four minutes, the resulting suspension became slightly brown in color. After two hours, a significant amount of solids remained in the heptane as a suspension. Very little ionic liquid product was formed in this step as judged by visual inspection. The suspension that was previously formed was then heated to reflux (a process step not described in the patent cited in the previous paragraph) and a further, rapid reaction took place forming an immiscible, brown ionic liquid phase with the heptane. Heating of the previously described composition was needed to form the desired ionic liquid. EXAMPLE 1 Two moles of aluminum trichloride (266.7 g) were added slowly to one mole of stirred trimethylamine hydrochloride salt (95.57 g) , both from Aldrich Chemical Co., under a blanket of dry air. The reaction was exothermic. A light brown liquid was formed. This liquid was stirred for one hour, and the liquid had a density of 1.4-1.5 g/cc at room temperature. The product was stable as a liquid at room temperature under a dry atmosphere. When cooled, it changed to a glassy viscous mass at -30°C. On warming to room temperature, it changed back to a flowable liquid. EXAMPLE 2 This Example is similar to Example 1 with the exception that the experiment was scaled up using a commercially available 70% aqueous solution of trimethylamine hydrochloride (Akzo Nobel Chemicals Inc.). A 200 g portion of the solution (170 cc) was evaporated in a porcelain dish until 60% of the liquid had evaporated. The slurry that formed was then introduced into a flask and was treated with low vacuum using an aspirator until all of the moisture had been removed. The solid was then mixed with two mole equivalents of aluminum trichloride in two steps. Half of the aluminum trichloride was slowly added with stirring. An exotherm occurred, and a brown liquid was formed. The second half of the aluminum trichloride was then added, and a final liquid was formed which stayed liquid at room temperature. The product was analyzed for its elemental composition. It had the formula (CH 3 ) 3 NH * A1 2 C1 7 . The results of the analysis are as follows: %A1 - 14.65% (Found), 14.90% (Calculated); %C1 - 67.5% (Found), 68.53% (Calculated); %C - 10.1% (Found), 9.94% (Calculated); %H - 1.0% (Found), 2.76% (Calculated); and %N - 4.0% (Found), 3.87% (Calculated). The nuclear magnetic - H - resonance spectra of aluminum showed that the aluminum was present as the heptachloroaluminate anion. EXAMPLE 3 This Example shows the alkylation of benzene with a Cι 2 olefin as the alkylating reagent to produce a linear fatty alkylbenzene using the ionic liquid made in Example 1. Five grams of dodecene and 30 g of benzene were weighed into a 3-neck flask. The liquids were heated to 80°C in a nitrogen atmosphere. A few samples were withdrawn before (time 0) and after the addition of 0.04 g of the ionic liquid made in Example 1. The samples were analyzed by GC and the results are shown below: SAMPLE TIME (MIN) CβHβ DODECENE CβHsCι 2 * A 0 85 . 7 14 .3 0 B 1 65 . 6 6 .2 28 . 6 C 15 62 . 9 0 . 1 36 .2 D 60 72 .3 0 27 . 6 * a mixture of dodecyl benzenes was used. The conversion of dodecene at 80°C in the excess of benzene was 100% after fifteen minutes of reaction. EXAMPLE 4 This Example illustrates the preparation of another ionic liquid useful as a catalyst in linear benzene alkylation. An ionic liquid comprising triethylamine hydrochloride and aluminum trichloride was prepared by introducing triethylamine hydrochloride (2.3 g, 16.7 mmol) into a flask and then introducing the aluminum trichloride (4.4 g, 33.4 mmol) from a dosing funnel. The reaction mixture immediately became sticky and, when approximately 50% of the aluminum trichloride had been added, it became completely fluid and brownish in color. The reaction was exothermic, and the temperature was kept at 30°C with the use of an ice bath. When all of the aluminum trichloride had been added, the product was slightly brownish in color and remained fluid at room temperature. The ionic liquid stayed in fluid liquid form until cooled to 0°C at which point it started to become a viscous composition and eventually a glassy material (at about -20°C) . EXAMPLE 5 This Example illustrates the preparation of another ionic liquid useful as a catalyst in linear benzene alkylation. Another ionic liquid was formed by introducing dibutylamine hydrochloride (2.5 g, 15.1 mmol) into a flask and then introducing the aluminum trichloride (4.0 g, 30.0 mmol) from a dosing funnel. The reaction mixture immediately became sticky and, when approximately 50% of the aluminum trichloride had been added, it became completely fluid and brownish in color. The reaction was exothermic, and the temperature was kept at 30°C with the use of an ice bath. When all of the aluminum trichloride had been added the product was slightly brownish in color and remained fluid at room temperature. The ionic liquid stayed in fluid liquid form until cooled to 0°C at which point it started to become a viscous composition and eventually a glassy material (at about -20°C) . EXAMPLE 6 This Example illustrates the preparation of another ionic liquid useful as a catalyst in linear benzene alkylation. Yet another ionic liquid was formed by introducing ethylamine hydrochloride (3.0 g, 36.8 mmol) into a flask and then introducing the aluminum trichloride (9.8 g, 73.6 mmol) from a dosing f nnel. The reaction mixture became sticky when approximately 50% of the aluminum trichloride had been added. When all of the aluminum trichloride had been added the product was completely fluid and brownish in color. The reaction was exothermic, and the temperature was kept at 40°C with the use of an ice bath. The mixture solidified below 35°C. EXAMPLE 7 This Example illustrates the preparation of another ionic liquid useful as a catalyst in linear benzene alkylation. Yet another ionic liquid was formed by introducing dibutylamine hydrochloride (2.4 g, 14.6 mmol) into a flask and then introducing ferric trichloride (4.7 g, 29.2 mmol) from a dosing funnel. The reaction mixture immediately became sticky and, when approximately 50% of the ferric trichloride had been added, it was completely fluid and deep brown to black in color. The reaction was exothermic. When all of the ferric trichloride had been added, the product was brown/black in color and solidified below 45°C. EXAMPLE 8 This Example illustrates the preparation of another ionic liquid useful as a catalyst in linear benzene alkylation. This Example is similar to Example 1, except that the metal halide was FeCl 3 . When 9.6 g of trimethylammonium chloride, 0.1 mole, was mixed with 32.4 g of FeCl 3 (0.2 mole) and warmed to 40° C, a reaction took place accompanied by an exotherm to about 70° C. A liquid was formed. The liquid was viscous at room temperature but very flowable above 50°C. EXAMPLE 9 This Example illustrates the preparation of another ionic liquid useful as a catalyst in linear benzene alkylation. This Example is similar to Example 1, except that the metal halide was ZnCl 2 . When 9.6 g of trimethylammonium chloride, 0.1 mole, was mixed with 27.2 g of ZnCl 2 , 0.2 mole, and heated to 100° C, a transparent colorless liquid was formed. Below this temperature, the material was transformed to a transparent glassy solid. EXAMPLE 10 This Example illustrates the preparation of another ionic liquid useful as a catalyst in linear benzene alkylation. This Example is similar to Example 1, except that the metal halide was CuCl. When 9.6 g of trimethylammonium chloride, 0.1 mole, was mixed with 19.8 g of CuCl , 0.2 mole, and heated to 50°C, a brown liquid was formed. The material stayed as a liquid above this temperature . EXAMPLES 11-13 These Examples illustrate the attempts at the preparation of a basic ionic liquid, a neutral ionic liquid, and an acidic ionic liquid. Only the acidic material was obtainable. In all the preparations, a three necked round bottom flask (50 mL) equipped with a nitrogen inlet and outlet, a thermometer and a dropping funnel with a large dosing opening, and a magnetic stirring bar were employed. All operations were carried out under a nitrogen atmosphere. "Basic ionic liquid" Dimethylamine hydrochloride (2.07 g, 25.4 mmol) was introduced into the flask, and A1C1 3 (1.7 g, 12.7 mmol) was added from the dropping funnel. When all the AlCl 3 had been added, the reaction mixture became light brown and sticky. The flask which contained the product mixture was placed in an oil bath and warmed slowly. When the temperature of the oil bath was above the 120°C, HC1 gas was formed, and the product decomposed. No ionic liquid was formed using these concentrations of the reagents and these conditions. "Neutral ionic liquid" Dimethylamine hydrochloride (2.06 g, 25.4 mmol) was introduced into the flask, and A1C1 3 (3.3 g, 24.7 mmol) was added from the dropping funnel. The addition of A1C1 3 was done rapidly, and the reaction was exothermic. When all the AICI3 had been added, the reaction mixture became light brown and liquid. When the reaction mixture was cooled to room temperature, it became a solid. The melting point of the reaction mixture was measured and was found to be 88°C. "Acid ionic liquid" Dimethylamine hydrochloride (1.96 g, 24 mmol) was introduced into the flask, and A1C1 3 (6.5 g, 48.8 mmol) was added from the dropping funnel. The addition of A1C1 3 was done rapidly, and the reaction was exothermic. When all the A1C1 3 had been added, the reaction mixture became light brown and liquid. When the reaction mixture was cooled to room temperature, it became a solid. The melting point of the reaction mixture was measured and was found to be 34"C. Example 14 This Example shows the alkylation of benzene to produce a linear fatty alkyl benzene using the ionic liquid made in Example 2. First, 24.04 g of benzene and 4.24 g of dodecene were weighed into a 3-neck flask. The mixture was then fluxed at 80°C under a nitrogen atmosphere. A sample was taken and was analyzed by GC. It showed that no reaction had taken place. Two minutes after addition of 1.85 g of the ionic liquid from Example 2 with similar heating, a sample was again taken and was analyzed by GC. It showed that dodecene had been converted to mono- and poly-dodecyl benzenes with 93% activity and 95% selectivity to mono-dodecyl benzene. The weight distribution of mono-dodecyl benzene isomers is given below: 2-dodecyl benzene 31.9% 3-dodecyl benzene 18.6% 4-dodeσyl benzene 15.7% 5- & 6-dodecyl benzene 32.5% The mixture was stirred at 80°C for an hour and was cooled to room temperature overnight. To demonstrate that the ionic liquid catalyst was reusable, 4.27 g of dodecene was added to the remaining solution containing the ionic liquid. The temperature increased to 43°C indicating that a rapid alkylation reaction took place. A sample was taken four minutes after the addition of dodecene. It showed that dodecene was 92% converted with 89% selectivity to mono-dodecyl benzene. The organic layer was subsequently separated from the ionic liquid. To further demonstrate the activity of the used ionic liquid, it was added to a freshly prepared solution of benzene (23.28 g) and dodecene (6.27 g) . The temperature increased to 47°C. A sample was analyzed, and it was found that dodecene had been 99% converted with 91% selectivity to mono-dodecyl benzene. Example 15 This Example also shows the alkylation of benzene to produce linear fatty alkyl benzene using the ionic liquid made in Example 2. First, 20.08 g of benzene and 5.39 g of dodecene were weighed into a 3-neck flask. The mole ratio of benzene to dodecene was 8:1. The flask was kept in an ice bath and was maintained at 0°C. A sample was taken and analyzed by GC. It shows that there had been no alkylation reaction. Two minutes after addition of 1.2 g of ionic liquid, the temperature increased to 30°C, a sample was taken and was analyzed by GC. It showed that dodecene had been converted to mono- and poly-dodecyl benzenes with 95% activity and 90% selectivity to mono- dodecyl benzene. The weight distribution of mono-dodecyl benzene isomers is given below: 2-dodecyl benzene 35.8% 3-dodecyl benzene 18.9% 4-dodecyl benzene 15.0% 5- & 6-dodecyl benzene 30.1% Example 16 In this Example, the procedure used in Example 2 was followed and 18 g of ionic liquid was prepared and placed at the bottom of a tube reactor . The reactor was kept at room temperature . A solution of 34.9 g of benzene mixed with 9.4 g of dodecene was then placed in a reservoir on top of the tube reactor. The mixed solution was bubbled through the ionic liquid at room temperature at an addition rate of 2 ml/min. After all the mixed solution had passed through the ionic liquid, it was analyzed by GC. This solution was recycled six times, with the conversion of dodecene to mono- and poly-dodecyl benzenes being shown below after each cycle: Cycle 1 19% Cycle 2 50% Cycle 3 72% Cycle 4 90% Cycle 5 89% Cycle 6 97% The weight distribution of mono-dodecyl benzene isomers in the sample after the sixth cycle is given below: 2-dodecyl benzene 37.9% 3-dodecyl benzene 19.2% 4-dodecyl benzene 14.2% 5- & 6-dodecyl benzene 27.9% Example 17 A 70% aqueous solution of trimethylamine hydrochloride salt, from Akzo Nobel Chemicals Inc., was used to prepare anhydrous trimethylamine hydrochloride salt. Two moles of aluminum trichloride, from Durham Chemicals, was then added slowly to one mole of the thus prepared anhydrous trimethylamine hydrochloride salt, with stirring. The reaction was exothermic. A grey-color liquid was formed. Some fine insoluble solid was observed suspending in the liquid. This liquid was used as a catalyst for the following benzene alkylation to make linear alkyl benzene. In the alkylation reaction, 30.2 g of benzene and 5.4 g of dodecene were weighed into a 3-neck flask . The mole ratio of benzene to dodecene was 12:1 with the flask being kept in an ice bath. A sample was taken and was analyzed by GC. It showed that there had been no alkylation reaction. Two minutes after addition of 1.3 g of ionic liquid, a sample was again taken and was analyzed by GC. It showed that dodecene had been completely converted (100% conversion) to mono- and poly- dodecyl benzenes at a 78% selectivity to mono-dodecyl benzene. The weight distribution of mono-dodecyl benzene isomers is shown below: 2- dodecyl benzene : 46.1% 3- dodecyl benzene : 19.9% 4- dodecyl benzene : 12.1% 5- and 6-dodecyl benzene : 21.8% Example 18 A 70% aqueous solution of trimethylamine hydrochloride salt, from Akzo Nobel Chemicals Inc., was used to prepare anhydrous trimethylamine hydrochloride salt. One and half moles of aluminum trichloride, from Durham Chemicals, was then added slowly to one mole of the thus prepared anhydrous trimethylamine hydrochloride salt, with stirring. The reaction was exothermic. A grey-color liquid was formed. Some fine insoluble solid was observed suspending in the liquid. This liquid became solid after overnight-standing at room temperature. It was gently heated to become liquid and used as a catalyst for the following benzene alkylation to make linear alkyl benzene. In the alkylation reaction, 26.7 g of benzene and 7.2 g of dodecene were weighed into a 3-neck flask. The mole ratio of benzene to dodecene was 8:1. The flask was kept at room temperature. A sample was taken and analyzed by GC. It showed that there had been no alkylation reaction. Two minutes after addition of 0.46 g of ionic liquid, a sample was again taken and was analyzed by GC. It showed that dodecene had been converted to mono- and poly-dodecyl benzenes with 98% conversion and 87% selectivity to mono-dodecyl benzene. The weight distribution of mono-dodecyl benzene isomers is shown below: 2- dodecyl benzene : 39.1% 3- dodecyl benzene : 19.1% 4- dodecyl benzene : 13.6% 5- and 6-dodecyl benzene : 28.2% EXAMPLE 19 This Example shows the alkylation of toluene with an alkylating agent carrying a functional group (oleonitrile) to produce tolylstearonitrile using the ionic liquid made in Example 1. Into a 250 ml flask was added 40 g of the ionic liquid made in Example 1 (0.11 mole) and 100 ml of toluene. To this was added 29 g of oleonitrile (0.11 mole) over a twenty minute period at room temperature. After the addition, the reaction was heated to 80°C and was maintained at this temperature for three hours. The reaction was distilled to remove excess toluene. Then, 250 ml. of heptane was added with vigorous stirring. The layers that formed were separated (heptane layer on top and ionic layer on the bottom) . The heptane layer was washed with water and was then distilled to collect the product as an undistillable residue. The residue was analyzed to be the desired product, tolylstearonitrile, in 70% yield and 80% purity. The ionic liquid layer was treated with 7.3 g of aluminum chloride (0.055 mole) and was used again in the same reaction with fresh oleonitrile and toluene. Workup by the same procedure, as described above, resulted in a yield of 54% for the desired product (tolylstearonitrile) . EXAMPLES 20-22 In a glovebox (under nitrogen atmosphere) two equivalents of aluminum trichloride were added to one equivalent of trimethylammonium chloride while stirring the mixture. This resulted in a grey cement-like viscous solution which was the desired ionic liquid for use, as the catalyst, as will be described below in the alkylation of benzene with 1-dodecylchloride (3.4 g) or 1-dodecene (2.8 g) under the conditions set forth in the Tables which follow. In the Tables which follow, the abbreviation W TMA(IL)" indicates a trimethylamine (TMA) hydrochloride- containing ionic liquid of the formula TMA.A1 2 C1 7 , while the other ionic liquids analogously utilize either triethylamine hydrochloride (TEA) , dibutylamine hydrochloride (DBA) , or the known methylbutylimidazolium (MBI) moiety. The abbreviation "S.M." refers to the alkylating agent starting material. Peak A in the Tables gives the amount of 6-dodecyl benzene, Peak B, the amount of 5-dodecyl benzene, Peak C of 4- dodecyl benzene, Peak D of 3-dodecyl benzene, Peak E of 2- dodecyl benzene, and Peak F of 1-dodecyl benzene. The first Table illustrates the alkylation of benzene under various conditions and depicts the results at the start and after ten minutes. The next two Tables illustrate multicycle benzene alkylations under the depicted conditions. Run T(oC) Catalyst SM t(Mιn ) SM Mono Di Tn Peak Peak Peak Peak Peak Side C12H26 A+B C D E F Products Isomers 20 TMA AI2CI7 Dodecylchloride 0 745 255 00 39 24 41 87 64 20 TMA AI2CI7 Dodecylchloπde 10 00 97 28 203 107 143 272 245 20 AICI3 Dodecylchloπde 0 305 666 28 83 49 91 235 209 20 AICI3 Dodecylchloπde 10 00 943 43 217 106 123 209 288 10 04 20 TMA AI2C17 1-Dodecene 0 478 380 81 44 74 43 74 189 x 02 20 TMA AI2CI7 1-Dodecene 10 00 824 118 32 187 103 163 371 x 14 20 AICI3 1-Dodecene 0 00 816 153 09 179 98 162 377 x 10 20 AICI3 1-Dodecene 10 00 836 127 16 184 101 165 386 x 10 9 60 TMA AI2CI7 Dodecylchloride 0 187 782 27 173 91 133 259 126 10 60 TMAAI2CI7 Dodecylchloride 10 00 950 21 251 126 153 261 159 26 03 11 60 AICI3 Dodecylchloride 0 00 946 35 239 119 139 233 216 16 03 12 60 AICI3 Dodecylchloπde 10 00 691 25 156 76 95 143 222 145 139 l • 13 60 TMA AI2CI7 1 -Dodecene 0 00 875 89 243 120 172 340 26 14 60 TMA AI2CI7 1 -Dodecene 10 00 891 8 253 126 174 338 19 15 60 AICI3 1 -Dodecene 0 00 905 62 03 251 127 174 353 19 16 60 AICI3 1 -Dodecene 10 00 816 46 21 268 134 156 258 86 20 17 20 TEA AI2CI7 Dodecylchloπde 10 00 963 22 247 121 143 244 208 000 04 18 20 DBAAI2CI7 Dodecylchloride 10 00 946 23 243 119 139 233 212 000 12 Benzene: 25 g; alkylating agent: 3.4 g; and catalyst: 16.6 mole% Cycle Catalyst SM Mono Di Tn Peak Peak Peak Peak Peak Remarks A+B C D E F 1 TMAAI2CI7 00 820 111 47 189 103 162 366 X IL soluble in benzene 2 TMA AI2CI7 00 800 125 52 184 99 157 36 X 3 TMA AI2CI7 00 831 103 40 204 106 163 358 X 4 TMA AI2CI7 787 139 25 12 35 19 29 56 X 5 TMA AI2CI7 826 104 19 10 28 15 22 39 X 1 DBA AI2CI7 00 894 62 19 235 125 178 356 X I L soluble in benzene 2 DBA AI2CI7 00 879 77 19 223 118 177 361 X 3 DBA AI2CI7 00 863 79 33 218 115 173 357 X 4 DBA AI2CI7 00 854 83 37 219 112 169 354 X 5 DBA AI2CI7 887 46 07 08 06 07 10 23 X 1 MBI AI2CI7 00 785 107 61 191 100 150 344 X I L not sol in benzene 2 MBI AI2CI7 00 804 102 47 206 106 156 336 X 3 MBI AI2CI7 00 807 103 51 214 107 156 330 X 4 MBI AI2CI7 00 819 91 49 224 111 159 325 X 5 MBI AI2CI7 00 823 87 41 230 112 159 322 X 6 MBI AI2CI7 591 329 38 91 46 64 128 X 7 MBI AI2CI7 908 36 10 05 07 14 X Benzene: 12 .5 g ; a! Lkylating agent: 1.4 g; and catalyst: 16.6 mole%. The tempera ture in all runs was : 20 c 'C, 1 -dodece ne was th< alkylating agent in all runs, an the time of ana lys: Ls was after ten minutes in all runs. Cycle Catalyst S M Mono Di Tri Peak Peak Peak Peak Peak Side C12H26 Remarks A+B C D E F Products Isomers TMA AI2CI7 00 886 22 210 103 120 201 252 65 TMAAI2CI7 00 717 10 155 75 89 146 252 251 TMA AI2CI7 00 965 21 238 116 136 232 243 08 06 TMA A2CI7 00 973 21 219 113 147 272 222 03 03 TMA AI2CI7 26 942 30 186 102 153 302 199 TMA AI2CI7 315 663 21 127 70 111 223 132 TMA AI2CI7 775 214 03 43 23 36 71 41 TMA AI2CI7 979 17 00 TMA AI2CI7 997 TMA AI2CI7 989 TMA A2ICI7 00 961 26 235 117 141 246 222 09 04 Extra catalyst 1 TMA A2ICI7 00 960 32 191 102 143 281 243 1 drop H20 2 TMA AI2CI7 937 51 00 08 10 05 08 15 13 3 drops H20 MBI AI2CI7 02 961 28 221 115 153 285 187 MBI AI2CI7 21 939 29 205 109 158 296 171 MBI AI2CI7 81 874 30 190 101 150 281 152 MBI AI2CI7 185 769 45 167 89 133 251 129 MBI AI2CI7 288 695 17 154 81 121 228 111 Benzene: 12 .5 aq→ ent : 1.4 gg;; aanndd catalyst: 16.6 mole The temperature in all runs was 20°C, 1-dodecene was the alkylating agent in all runs, and the time of analysis was after ten minutes in all runs. The preceding Examples are presented for illustrative purposes only and, for that reason, should not be construed in a limiting sense. The scope of protection sought is set forth in the Claims which follow.

Claims: We Claim : 1. A process for linear alkylbenzene formation using, as a catalyst, a low temperature molten ionic liquid composition comprising a mixture of a metal halide and a base and an alkylating agent selected from the group consisting of a chloroalkane having an average carbon atom content of more than six, an olefin having an average carbon atom content of more than ten, and a mixture of the chloroalkane and the olefin. 2. The process of Claim 1 wherein the metal halide is a covalently bonded metal halide. 3. The process of Claim 2 wherein the metal of the metal halide is selected from the group comprised of aluminum, gallium, iron, copper, zinc, and indium. 4. The process of Claim 3 wherein the metal halide is aluminum trichloride. 5. The process of Claim 1 wherein the alkyl-containing amine hydrohalide salt contains three alkyl groups. 6. The process of Claim 1 wherein the ionic liquid composition has a mole ratio of the alkyl-containing amine hydrohalide salt to metal halide of from about 1:1 to about 1:2.5. 7. The process of Claim 1 wherein the alkyl-containing amine hydrohalide salt is of the formula R 3 N.HX where at least one R group is alkyl. 8. The process of Claim 7 wherein the alkyl- containing amine hydrohalide salt is of the formula R 3 N.HX where at least one R group is alkyl and the metal halide contains a metal which is selected from Group VIII, Group IB, Group IIB and Group IIIA of the Periodic Table of The Elements. 9. The process of Claim 8 wherein the metal halide is selected from the group consisting of a chloride of aluminum, copper, iron, and zinc. 10. The process of Claim 1 wherein the ionic liquid composition has a mole ratio of the alkyl-containing amine hydrohalide salt to metal halide of from about 1:1 to about 1:2.5, the metal halide is aluminum trichloride, and the alkyl-containing amine hydrohalide salt is trimethylamine hydrochloride. 11. A process as claimed in Claim 1 wherein dodecene is reacted with benzene. 12. A process as claimed in Claim 1 wherein dodecene is reacted with benzene, the ionic liquid composition has a mole ratio of the alkyl-containing amine hydrohalide salt to metal halide of from about 1:1 to about 1:2.5, the metal halide is aluminum trichloride, and the alkyl-containing amine hydrohalide salt is trimethylamine hydrochloride. 13. A process as claimed in Claim 1 wherein dodecyl chloride is reacted with benzene. 14. A process as claimed in Claim 1 wherein dodecyl chloride is reacted with benzene, the ionic liquid composition has a mole ratio of the alkyl-containing amine hydrohalide salt to metal halide of from about 1:1 to about 1:2.5, the metal halide is aluminum trichloride, and the alkyl-containing amine hydrohalide salt is trimethylamine hydrochloride . 15. A process as claimed in Claim 1 wherein the reaction uses an alkylating agent carrying a functional group that is substantially nonreactive with the catalyst. 16. A process as claimed in Claim 15 wherein the alkylating agent is oleonitrile. 17. A process as claimed in Claim 1 wherein the base in the ionic liquid is select from the group consisting of a quaternary ammonium salt, an imidazoline or alkyl- substituted imidazoline salt, a pyridinium or alkyl- substituted pyridinium salt, a sulfonium or alkyl- substituted sulfonium salt, or a phosphonium or alkyl- substituted phosphonium salt. 18. A low temperature molten ionic liquid composition comprising the reaction product of a metal halide and an alkyl-containing amine hydrohalide salt selected from the group consisting of a monoalkyl-, a dialkyl-, a trialkyl- containing amine hydrohalide salts, and mixtures thereof. 19. The composition of Claim 18 wherein the alkyl- containing amine hydrohalide salt is of the formula R 3 N.HX where each R group is alkyl of from one to eight carbon atoms. 20. The composition of Claim 18 wherein the metal halide contains a metal which is selected from Group VIII, Group IB, Group IIB and Group IIIA of the Periodic Table of The Elements. 21. A low temperature molten ionic liquid composition comprising the reaction product of aluminum trichloride and an alkyl-containing amine hydrohalide salt selected from the group consisting of a monoalkyl-, a dialkyl-, a trialkyl- containing amine hydrohalide salts, and mixtures thereof. 22. The composition of Claim 21 wherein the alkyl- containing amine hydrohalide salt is of the formula R 3 N.HX where each R group is alkyl of from one to four carbon atoms . 23. The composition of Claim 22 wherein each alkyl group is methyl. 24. A process for forming a low temperature molten ionic liquid composition, comprising a mixture of a metal halide and an alkyl-containing amine hydrohalide salt, which comprises mixing together a solid halide and a solid alkyl- containing amine hydrohalide salt. 25. The process of Claim 24 wherein the metal halide is a covalently bonded metal halide selected from the group consisting of aluminum, gallium, iron, copper, zinc, and indium. 26. The process of Claim 24 wherein the metal halide is aluminum trichloride and the alkyl-containing amine hydrohalide salt contains three alkyl groups. 27. The process of Claim 26 wherein the three alkyl groups are each methyl . 28. A process for linear alkylbenzene formation using, as a catalyst, a low temperature molten ionic liquid composition comprising a mixture of a metal halide and an alkyl-containing amine hydrohalide salt. 29. The process of Claim 28 wherein the metal halide is aluminum trichloride. 30. The process of Claim 28 wherein the alkyl- containing amine hydrohalide salt is of the formula R 3 N.HX where at least one R group is alkyl and the metal halide contains a metal which is selected from Group VIII, Group IB, Group IIB and Group IIIA of the Periodic Table of The Elements . 31. The process of Claim 28 wherein the ionic liquid composition has a mole ratio of the alkyl-containing amine hydrohalide salt to metal halide of from about 1:1 to about 1:2.5, the metal halide is aluminum trichloride, and the alkyl-containing amine hydrohalide salt is trimethylamine hydrochloride . 32. A process as claimed in Claim 28 wherein dodecene is reacted with benzene, the ionic liquid composition has a mole ratio of the alkyl-containing amine hydrohalide salt to metal halide of from about 1:1 to about 1:2.5, the metal halide is aluminum trichloride, and the alkyl-containing amine hydrohalide salt is trimethylamine hydrochloride. 33. A process as claimed in Claim 28 wherein dodecyl chloride is reacted with benzene, the ionic liquid composition has a mole ratio of the alkyl-containing amine hydrohalide salt to metal halide of from about 1:1 to about 1:2.5, the metal halide is aluminum trichloride, and the alkyl-containing amine hydrohalide salt is trimethylamine hydrochloride . 34. A process as claimed in Claim 28 wherein the reaction uses an alkylating agent carrying a functional group that is substantially nonreactive with the catalyst. 35. A process as claimed in Claim 34 wherein the alkylating agent is oleonitrile.

Inventors: GRECO CARL C, LACROIX CHRISTINE P M, SHERIF FAWZY G, SHYU LIEH-JIUN, TALMA AUKE G, GRECO, CARL, C., LACROIX, CHRISTINE, P., M., SHERIF, FAWZY, G., SHYU, LIEH-JIUN, TALMA, AUKE, G.
Applicants: AKZO NOBEL NV, GRECO CARL C, LACROIX CHRISTINE P M, SHERIF FAWZY G, SHYU LIEH JIUN, TALMA AUKE G, AKZO NOBEL N.V., GRECO, CARL, C., LACROIX, CHRISTINE, P., M., SHERIF, FAWZY, G., SHYU, LIEH-JIUN, TALMA, AUKE, G.
Application year: 1997
Main classification: C07C2
IPC codes: B01J31, B01J35, C07B61, C07C2, C07C15