KR960006255B1 - Method of benzene alkylation using fluorided silica-alumina and linear c6-c20 olefin - Google Patents

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Description

Benzene Alkylation Process Using Fluorinated Silica-Alumina and Straight C6-C20 Monoolefins

More than 50 years ago, alkylbenzene sulfonates (ABS) were recognized in many ways to be much more effective cleaning agents than natural soaps. ABS has quickly become the standard surfactant in the detergent industry by replacing soap as a household laundry and dishwashing application because of its lower cost, price stability and efficiency in a wide range of detergent formulations.

Initially prepared alkylbenzene sulfonates had substantially branched alkyl chains. This situation continued, and by the early 1960s it became apparent that branched chain alkyl-based cleaners contaminated ponds and streams. As a result of investigating this problem, it was found that the branched chain structure of the alkyl chain is not rapidly biodegraded, so that the surfactant activity of the cleaning agent is maintained for a long time. This was not the case with the use of natural soaps in the past.

After recognizing the biodegradability of ABS based on alkylation with straight chain olefins, the industry has become interested in the production of unbranched olefins and their continued use in the production of straight chain alkylbenzenes. A method for effectively alkylating benzene with commercially available feedstock containing straight chain olefins has been developed, and the process for producing straight chain alkylbenzenes (LABs) has become another reliable method. Increasingly, hydrogen fluoride (HF) catalyzed alkylation has been found to be particularly effective in the production of LABs, and the HF-based alkylation process has become an industry standard method.

As environmental concerns increase, there is an increasing awareness that the use of HF and its ancillary products need to study the same or better substitutes in many respects. The criteria other than the cost used in this study are the conversions performed by the catalyst, the selectivity of the monoalkylbenzene formation and the linearity of the alkylbenzenes produced.

Alkylation is typically performed using excess benzene relative to olefins. An ideal catalyst would exhibit an olefin conversion of 100% using the same molar ratio of benzene and olefins, but this result was not obtained, so try to obtain the maximum olefin conversion using a molar ratio of benzene to about 30 olefins or less. . The better the catalyst, the lower the benzene: olefin molar ratio at high conversions, eg 98%. The conversion at a constant value of benzene: olefin ratio is a measure of catalytic activity (the ratio should not be too high so that the conversion at this ratio is constant or slightly changed). The conversion rate can be represented by the following formula.

Where V is the conversion, C is the number of moles of olefin consumed, and T is the number of moles of olefin initially present.

Even if the catalyst has activity, it is not effective without selectivity. Selectivity is defined as the percentage of total olefins consumed under reaction conditions which appear as monoalkylbenzene and can be represented by the following formula.

Where S is selectivity, M is the number of moles of monoalkylbenzene produced and C is the number of moles of olefin consumed. The better the selectivity, the more preferable the catalyst. Approximate measurement of selectivity is obtained by the following equation.

Here, "total product" includes monoalkylbenzenes, polyalkylbenbenes and olefin oligomers. At high selectivity (S> 85%), the results calculated from the two equations are nearly identical. Since the distinction between oligomers and polyalkylbenzenes is difficult, it is common practice to use practically approximate measurements.

Finally, the reaction of the theoretical straight chain olefin with benzene proceeds according to the following reaction formula.

C ₆ H ₆ + R ₁ CH = CHR ₂ → C ₆ H ₅ CH (R ₁ ) CH ₂ R ₂ + C ₆ H ₅ CH (R ₂ ) CH ₂ R ₁

Note that the branched chain is branched alone in benzyl carbon and contains only one branch in the chain. Strictly speaking, this is not straight chain alkylbenzenes, but despite the terminology arising in the process, the product will contain alpha-branched chain olefins because the alkyl groups include straight chain alkylbenzenes, which are substances derived directly from the straight chain olefins. . The alkylation catalyst rearranges the olefins to produce a product that is not readily biodegradable (see above), for example α, α-disubstituted olefins, which continuously react with benzene to branch off carbon other than benzyl carbon. Because of the production of alkylbenzenes, the degree of effect of the catalyst on the formation of linear alkylbenzenes is another important catalyst parameter.

Straight chain can be represented by the following formula.

Where D is the linearity, L is the number of moles of the resulting linear monoalkylbenzene, and M is the number of moles of the monoalkylbenzene produced.

As a result, the ideal catalyst is one with V is 100, S is 100 and D is 100. The minimum requirement is at least 85% selectivity and at least 98% linearity at at least 98% conversion. This is a minimum requirement, that is, a catalyst that does not meet all of the above requirements at the same time is not commercially acceptable.

The linearity requirement is considered to have increased importance and severity when viewed in some areas of the minimum standard that the linearity in detergents of 92-95% will increase to 95-98% by about 2000. Since the olefin feedstock used for alkylation generally contains a small proportion of non-chain olefins (typically in many processes the non-linear olefin content is about 2%), the desired linearity in the detergent alkylates is higher. Requires catalytic performance. That is, the original linearity of the alkylation process should be increased by the amount of non-linear olefins present in the feedstock. For example, when using a feedstock containing 2% non-chain olefins, the catalyst must be alkylated with 92% straight chain to obtain a product with 90% straight chain, and contains 4% non-chain olefin. If feedstock is used, the catalyst must be alkylated with 94% linearity to obtain 90% linearity of the product.

As a result of diligent study by the present inventors, as a solution to the problem of studying a catalyst for detergent alkylation that satisfies all of the above-mentioned criteria and particularly meets the stringent requirement of increased linearity, isomerization of linear olefins to non-linear olefins ( This process results in the production of non-chain detergent alkylates from the straight chain olefin feedstock), which is relatively insensitive to certain candidate catalysts for the preparation of detergent alkylates, but is quite sensitive to temperature. This result is quite surprising in itself, but more importantly, therefore, suggests that performing alkylation at low temperatures is important for further improving product linearity. Subsequently, attention has been drawn to the study of more active catalysts, ie materials that catalyze detergent alkylation at lower temperatures.

It is well known to use silica-alumina as a support for various metals in the alkylation of aromatics with olefins. For example, U. S. Patent No. 3,169, 999 describes catalysts based on small amounts of nickel and chromia on silica-alumina supports, and U. S. Patent No. 3,201, 487 describes 25-50 wt.% Chromia on silica-alumina supports. Are described, all of which are used to alkylate aromatics with olefins. Crystalline aluminosilicates that act as catalysts in detergent alkylation are disclosed in US Pat. Nos. 4,301,317 and 4,301,316. US Pat. No. 4,358,628 discloses an alkylation process using olefins using a tungsten oxide catalyst supported on a porous silica-alumina support containing 70-90% silica, prepared by a very specific route.

As a more intimate document, European Patent Publication No. 0160145 discloses the use of amorphous silica-alumina as catalyst in alkylation for cleaning, having pores of specific channel or network structure and having at least 10% of cationic sites occupied by ions other than alkali or alkaline earth metals. Is disclosed. In a much closer literature, in the patent of US Pat. No. 4,870,222, porous silica-alumina relates to a process for the preparation of monoalkylated aromatic compounds, which first alkylates the aromatics, separates the mixture of products, and then transalkylates the polyalkylated materials. It is disclosed that the most preferred catalyst for alkylation.

In the literature, it seems to be rare for fluorinated silica-alumina. Japanese Patent Laid-Open Publication No. 02237641 discloses contacting silica-alumina (20% silica) with CCIF ₃ at 400 ° C. to obtain 28% of higher activity and longer operating life in the manufacture of cumene by vapor phase alkylation of benzene. It is disclosed to provide a catalyst containing fluorine. Kurosaki and Okazaki's literature [ 63, 2363 (1990) disclose silica: alumina (6.7: 1) modified by vapor phase fluorination with CClF ₃ at 350-550 ° C. in alkylation of benzene with propylene [Ref. Kurosaki and Okazaki, Chemistry letters, 589 (1991)]. However, in any of the prior art, the advantages of fluorinated silica-alumina, which can provide higher linearity to the product obtained in the detergent alkylation process, in particular the silica-alumina prepared by this method and containing the fluorine content described herein. I didn't recognize it.

It is an object of the present invention, in particular, that benzene is characterized by olefins, characterized by carrying out alkylation with at least 98% olefin conversion, at least 85% conversion of olefins to monoalkylbenzenes and at least 90% straight chains for monoalkylbenzene formation. By alkylation in a continuous manner, straight chain alkylbenzenes are prepared. In one embodiment, benzene is reacted with a C ₆ -C ₂₀ linear monoolefin or mixture of linear monoolefins in the presence of a catalyst consisting of fluorinated silica-alumina. In this case, the weight ratio of silica to alumina is about 1: 1 to about 9.1, the molar ratio of benzene to monoolefin is 5: 1 to 30: 1, and the fluoride content of the catalyst is 1 to 6 wt%. Other embodiments will become apparent as described below.

Since the linearity of the alkyl chains is regarded as an increasingly important environmental regulatory item, the present inventors have studied catalysts which carry out alkylation by a continuous process at acceptable production rates at temperatures of up to 140 ° C. Acceptable productivity for this purpose means an hourly space velocity of at least 0.05 hr ⁻¹ olefin liquid. The inventors have found that when fluorinating silica-alumina, a substantial increase in activity can be obtained over non-fluorinated materials for at least a particular composition range of silica-alumina. More specifically, the inventors of the present invention found that silica-alumina containing 50 to 90% by weight of silica and 1 to 6% by weight of fluorine, calculated as fluoride in the finished product, is a detergent at a temperature of 140 ° C. or less. It has been found that cleaning alkylation is performed at a conversion rate of at least 98%, providing a catalyst that is surprisingly suitable for alkylation and provides at least 85% selectivity to monoalkylbenzenes having at least 90% alkyl side chain linearity.

Feedstocks used in the practice of the present invention are typically obtained from the dehydrogenation of paraffins. The entire dehydrogenation mixture sometimes does not complete the dehydrogenation reaction to minimize cracks, isomerization and other undesirable and toxic byproducts. Without removing the branched chain olefins formed in the dehydrogenation reaction, the total amount of non-linear alkylbenzenes formed should be sufficiently small that the monoalkylate can meet the requirement of 90% linearity. Polyolefins formed during dehydrogenation are minimized in the feedstock used in the practice of the present invention. As a result, the feedstock is usually unreacted paraffin, small amounts (about 2%) of branched chain olefins, and typically C ₆ -C ₂₀ , preferably C ₆ -C ₁₆ , even more preferably C ₁₀ -C A mixture of ₁₄ unbranched straight chain monoolefins. It can be unsaturated at any point on a straight monoolefin chain and requires a requirement for the position of the double bonds, but the requirements for the straightness of the olefin must be met (Ref. RA Myers, "Petroleum Refining Processes", 4- 36 to 4-38, McGraw Hill Book Company (1986).

The linear monoolefin in the feedstock is reacted with benzene. The stoichiometric amount of the alkylation reaction requires a molar ratio of only 1 mole of benzene per mole of total straight chain monoolefin, but using a 1: 1 mole ratio results in excessive olefin polymerization and polyalkylation. However, it is desirable to use a benzene: olefin molar ratio close to 1: 1 to maximize possible benzene utilization and minimize recycling of unreacted benzene. Thus, the substantial molar ratio of benzene to total monoolefins has an important effect on the conversion and more importantly the selectivity of the alkylation reaction. A total benzene: chain monoolefin molar ratio of 5: 1 to 30: 1 is preferred for carrying out alkylation with the desired conversion, selectivity and linearity with the catalyst of the invention, although this process is typically 8: 1 to 20 The molar ratio of total benzene to linear monoolefin of 1 is also satisfactory.

Benzene and straight chain monoolefins are reacted under alkylation conditions in the presence of the catalyst of the present invention. These alkylation conditions include temperatures of 80 ° C to 140 ° C, most typically 135 ° C or less. Since the alkylation is carried out in the liquid phase process, the pressure should be sufficient to keep the reactants in the liquid state. The required pressure depends primarily on feedstock and temperature, but is typically 200-1000 psig (1480-6996 kPa), most typically 300-500 psig (2170-3549 kPa).

The alkylation of benzene with the necessary conversion, selectivity and straight chain by linear monoolefins is carried out on fluorinated silica-alumina containing a weight ratio of silica to alumina of 1: 1 (50% by weight) to 9: 1 (90% by weight). Is performed by. This range is effective in terms of selectivity and activity. The selectivity of the fluorinated silica-alumina of the present invention increases with increasing silica content, suggesting and recommending that the higher the silica concentration possible, the more effective it is. However, the activity of the fluorinated material initially increases and appears to be maximum at a ratio of silica: alumina of about 3: 1 and then decreases. Thus, although fluorinated silica-alumina can be used over the ranges given above, it is preferred to use a silica to alumina weight ratio of about 65:35 to 85:15.

Preferred catalysts contain about 1-6% by weight of fluoride based on the final silica-alumina catalyst from which volatiles have been removed. Higher concentrations of fluoride can be used without a substantial incremental benefit. Preferred fluoride concentrations depend on the silica: alumina ratio. For example, for a silica: alumina ratio of 75:25, a fluoride concentration of about 1.5 to 3.5 is preferred.

Amorphous cogelled oil-drop silica-alumina is preferred for successful implementation of the present invention. Other silica-aluminas of the same apparent composition can be used but are generally coarser than amorphous cogelled oil-drop products. Oil-drop methods for preparing materials are disclosed in US Pat. No. 2,620,314.

Cogelled silica-alumina compositions are suitably prepared as spheroidal particles by an oil-drop method. In a preferred method of preparation, the alumina sol used as the alumina source is mixed with an acidified glass solution as the silica source and the mixture is added with a suitable gelling agent such as urea, hexamethylenetetramine (HMT), or a mixture thereof. Mix with. The mixture is discharged into a hot oil bath maintained at or below the gelling temperature by a nozzle or rotating disk. The mixture is dispersed as droplets in a hot oil bath to form spherical gel particles.

The long-lasting gel particles produced by the oil-drop method are typically aged in an oil bath for at least 10-16 hours and then at least 3-10 hours in a suitable alkali or basic medium and finally water washed. Proper gelation in the oil bath of the mixture as well as subsequent aging of the spherical gel is not readily achieved at temperatures below about 50 ° C., at about 100 ° C. gas tends to be released quickly, rupturing or weakening the spherical gel.

The spherical gel is washed with water, preferably water containing small amounts of ammonium hydroxide and / or ammonium nitrate. After washing, it is dried for at least 6 to 24 hours at a temperature of 85 to 250 ° C. and then calcined for at least about 2 to about 12 hours at a temperature of about 300 to 760 ° C.

The fluorinated silica-alumina catalyst of the present invention is prepared by impregnating silica-alumina mainly with hydrogen fluoride. This does not mean that HF is the only fluoride source, and that the fluoride source is equivalent to HF and analytically contains only additional HF when providing fluorinated silica-alumina without additional metals or metal sources. Examples of suitable fluoride sources other than HF include ammonium fluoride [NF ₄ F], ammonium bifluoride [NH ₄ HF ₂ ] and organic fluorides. When ammonium fluoride is used, NH ₃ is volatilized while subsequently heating the fluoride impregnated silica-alumina. If organic fluoride is used, the impregnated silica-alumina is subsequently heated under conditions where carbon is oxidized to carbon dioxide and excess hydrogen to water to volatilize them so that the equivalents of the HF impregnated product remain.

The fluorinated silica-alumina catalyst can be prepared by various methods depending on the fluoride source, the desired fluoride concentration, and the like. For example, when using ammonium fluoride, the aqueous solution of ammonium fluoride containing silica-alumina and the desired amount of fluoride is mixed intimately in the same volume (e.g., cold rolled), and the mixture is then heated to water Evaporate. The resulting fluoride impregnated product may be dried at 125 to 175 ° C. for several hours and then calcined for 1 to 6 hours depending on the use temperature, typically at a temperature of 350 to 550 ° C. The time of firing in the vicinity of 400 degreeC is generally about 3 hours. It has been found that ammonia is lost from the catalyst when the impregnated material is heated at about 150 ° C. Not much of the fluoride was lost at temperatures below about 550 ° C., but at higher temperatures a loss of fluoride was observed.

Similar impregnation methods can be used when HF is a fluoride source, but the catalyst can also be fluorinated by HF airflow. In the latter case, no drying step is required and the fluorinated material can be fired directly. When using organic fluorides, either silica or alumina can be impregnated using either vapor or liquid fluoride sources. For example, an organic fluoride such as t-butyl fluoride is impregnated from a solution in a volatile solvent, and then the solvent is removed by evaporation, the silica-alumina is heated to remove the final traces of the solvent, and then calcined to organic material. Can be removed. This method is similar to impregnation with inorganic fluoride but can experience fluoride loss upon firing. Alternatively, t-butyl fluoride can be volatilized and HF deposited on silica-alumina via pyrolysis of t-butyl fluoride. The fluoride concentration can be controlled by gas flow rate, exposure time and exposure temperature.

The catalyst of the present invention has been found to be quite sensitive to water. Therefore, it is preferable to dry the feedstock at a concentration of 1 ppm or less. As the water content of the feedstock increased, the catalyst was found to deactivate. It is also highly desirable to completely dry the catalyst just before use. This can be done successfully by heating the catalyst in a dry inert gas such as air or nitrogen at a temperature above 150 ° C., preferably higher. The time required for proper drying depends on such factors as gas flow rate and temperature, but at 300 ° C., about 6 to 12 hours seem to be appropriate.

Alkylation of benzene with straight monoolefins of the invention can be carried out by either a batch process or a continuous process, but the continuous process is more preferred and will be described in more detail. Fluorinated silica-alumina catalysts can be used as the packing layer or the fluidized bed. The feedstock may pass upstream or downstream to the reaction zone, or may pass flat and horizontally in the emissive bed reactor. Mixtures of feedstocks containing benzene and total chain monoolefins can be introduced at a total benzene: olefin ratio of 5: 1 to 30: 1, with a typical ratio of 8: 1 to 20: 1. In a preferred variant, the olefin can be fed to several separate points in the reaction zone and the benzene: olefin ratio in each zone can exceed 30: 1. However, the total benzene: olefin ratio used in this variant of the invention should be within the above-mentioned range. The total feed mixture, which is a mixture of feedstock containing benzene and straight chain monoolefin, has a liquid mash space velocity of 0.3 to 6 ^{hr −1} (depending on the alkylation temperature, the time of use of the catalyst, the ratio of silica to alumina and the fluorine concentration in the catalyst) LHSV) through the packing layer. The temperature in the reaction zone is maintained at 80-140 ° C., and the pressure may vary generally in the range of 200-1000 psig (1480-7000 kPa) for liquid phase alkylation. After passing the benzene and straight chain monoolefin feedstock through the reaction zone, the effluent is collected and separated into benzene recycled to the feed end of the reaction zone, paraffin recycled to paraffin dehydrogenation units, and alkylated benzene. The alkylated benzenes are usually further separated into monoalkylbenzenes which are then used in the sulfonation for the preparation of straight chain alkylbenzene sulfonates, and oligomers and polyalkylbenzenes. As a result of the reaction, a conversion of 98% or more was obtained, so that very little unreacted monoolefin was recycled together with paraffin.

When the aromatics, in particular benzene, are alkylated with monoolefins having 6 to 20 carbon atoms, more usually 8 to 16 carbon atoms, especially 10 to 14 carbon atoms, the mixture of monoalkylated aromatic compounds obtained is Usually referred to as detergent alkylate.

Sulfonation of detergent alkylates is carried out by various reagents including a mixture of sulfuric acid and sulfur trioxide, variously known sulfuric acid, fuming sulfuric acid and oleum, sulfur trioxide, and a small amount of chlorosulfonic acid ClSO ₃ H, also known as chlorosulfuric acid. Can be done. The advantage of sulfuric acid as a sulfonating agent is that it is convenient and inexpensive. However, sulfonation of the aromatic ring with sulfuric acid results in water that dilutes the sulfuric acid used as the sulfonating agent to substantially reduce its activity, and therefore requires 3 to 4 molar ratios of sulfuric acid per mole of aromatic compound in order to be properly converted. . Another disadvantage of using sulfuric acid as the sulfonating agent is the need to recover the spent sulfuric acid from the diluted sulfuric acid solution.

The use of fuming sulfuric acid can prevent many of these problems. In particular, the use of a mixture of sulfur trioxide and sulfuric acid can preferably carry out a reaction which does not produce water with sulfur trioxide. As a result, the formation of consumed acids is reduced, and a relatively smaller molar ratio of reagent is required than when sulfuric acid is used alone. Sulfuric acid is much less diluted than when sulfuric acid is used alone as a sulfonating agent, so sulfuric acid recovery is facilitated.

Recently, sulfur trioxide has been selected as a sulfonating agent. As mentioned earlier, the reaction with the aromatic ring in this case does not produce water as a by-product, and because of its extreme reactivity, trace amounts of sulfur trioxide are required for the aromatic ring being sulfonated. Various commercial methods use an inert dry gas, often air-dilute sulfur trioxide gas, to provide sulfonated mixtures containing generally up to 20% by volume sulfur trioxide. It is desirable to dilute sulfur trioxide to control the reaction between the extremely active sulfonating agent sulfur trioxide and aromatics. The extreme reactivity of sulfur trioxide can be controlled by complexing it with a Lewis base such as amine, dioxane, dimethylformamide, dimethyl sulfoxide and the like. In theory, the use of chlorosulfonic acid as a sulfonating agent can be quite advantageous, but hydrogen chloride is formed as a byproduct, and the acceptance of it as a sulfonating agent is decreasing, especially with the advent of various methods using sulfur trioxide.

Sulfonation conditions may of course vary depending on the sulfonating agent used and are well known to those skilled in the art. When 100% sulfuric acid is used as the sulfonating agent, the reaction temperature is often in the range of 45 to 55 ° C., and a sufficient amount of sulfuric acid, typically molar excess of sulfuric acid, is used in the range of about 1.5 to about about the alkylate of the detergent. Use at 4 molar ratios. When sulfuric acid is used the reaction is a significant exothermic reaction and therefore it is necessary to cool the reaction mixture continuously to keep the temperature within the desired range. When fuming sulfuric acid is used, it is generally preferred to react the mixture containing 20 to 30% sulfur trioxide, typically at a reaction temperature of 30 to 45 ° C. The reaction time is generally short, on the order of minutes, and the mole ratio of oleum may be about 1.1 per mole of detergent alkylate. As in sulfuric acid, spent acid is formed even when fuming sulfuric acid is used as the sulfonating agent. In general, this is simply separated by dilution of the sulfonated mixture with water under the desired strong cooling due to the high pyrogenicity upon dilution. The water insoluble monosulfonated product can then precipitate as a collectable oil insoluble and water incompatible layer, and then sulfuric acid can be recovered from the aqueous phase.

The advantage of using sulfur trioxide as the sulfonating agent is that no water is produced and there is no need to recover the spent sulfuric acid. The most commonly used method of sulfur trioxide is the use of a dilute sulfur trioxide stream containing usually 2-20% by volume of sulfur trioxide as a vapor diluted with an inert dry carrier gas (usually air). Sulfonation using sulfur trioxide is usually carried out at a temperature range of about 25 to 120 ° C., with the reaction temperature typically being maintained below 100 ° C., with a preferred temperature range of 30 to about 75 ° C. Sulfur trioxide vapor can be effectively diluted by carrying out sulfonation under reduced pressure. Only a slight excess of sulfur trioxide is required relative to the detergent alkylate, and typical ratios of sulfur trioxide to alkylate are on the order of 1.05: 1 to 1.2: 1.

The mixture of alkylbenzene sulfonic acids obtained after sulfonation is neutralized to form sodium and / or much smaller amounts of other alkali metal salts. This is usually done by reacting the alkylbenzene sulfonic acid with a suitable aqueous base of an alkali metal, such as an alkali metal hydroxide or an alkali metal carbonate. After sulfonating the detergent alkylate, the resulting alkylbenzene sulfonic acid mixture is neutralized by passing through a saponification zone, where the sulfonation reaction mixture is mixed with an aqueous stream containing ammonia, sodium hydroxide or potassium hydroxide. For example, neutralization with sodium hydroxide produces an alkyl aromatic monosulfonate sodium salt. The neutralization product can be used directly as a modified oil recovery surfactant, or it can be subjected to a separation step to obtain a higher purity target product. For example, this mixture is typically passed through an extraction zone to extract the sulfonate from the unreacted hydrocarbon material by an aqueous mixture of alkyl alcohols containing from 25 to 60% by weight of isopropyl alcohol, which is preferred as a solvent. The propyl alcohol solution can be easily stripped from the extraction stream to obtain purified sulfonate.

EXAMPLE

Common way

The catalyst was packed into a 12.7 mm (0.5 in) diameter and 203.2 mm (8 in) length equipped with slide thermocouple to measure bed temperature at various depths. A feedstock containing a linear monoolefin is obtained by dehydrogenation of n-paraffins and has the composition described below.

Table 1 Feedstock Composition (% by weight)

Branched Chain Hydrocarbons 7.9

Unbranched hydrocarbons 92.1

A feedstock containing linear olefins and benzene in a benzene: olefin molar ratio of 15: 1 was fed upstream to the packing layer of the catalyst under the conditions described in the table. The emission was analyzed by gas chromatography. After the reactor was run, ie equilibrated, the analysis was carried out.

All silica-alumina catalysts were prepared by oil-drop method as spherical 1.6 mm (1/6 inch) diameter and fluorinated by impregnation with aqueous ammonium bifluoride solution containing the desired amount of fluoride. The fluoride impregnated material was dried at 150 ° C. and then calcined for 3 hours in air at 400 ° C. to provide the catalyst described below. Clay is montmorillonite clay commercially available as Filtrol 24.

Example 1

1-decene reaction

Non-fluorinated silica-alumina (catalysts A and E), montmorillonite clay (catalyst J) and fluorinated silica-alumina (catalyst G) were subjected to a temperature of 135-150 ° C., 500 psig (3550 kPa), and LHSV of 2hr- ¹ The effect on 1-decene in the absence of benzene was evaluated by passing through a stream of 1-decene in n-decane (1:10 weight ratio) as solvent on the furnace bed. Emissions were analyzed for dimers, trimers, cracked products and methylnonene. The latter results from alkyl group migration and isomerization at 1-decene and can be considered to measure the tendency to produce non-chain alkylates while the catalyst alkylates benzene with 1-decene. The results are shown in Table 1.

Table 1. Conversion of 1-decene without benzene

a. Cracked product

b. Methylnonene (branched chain olefins)

c. Absolute yield (%) of methylnonene (conversion × selectivity)

As far as conversion is related to catalytic activity, the data clearly shows that fluorinated silica-alumina is the most active catalyst and fluorination plays an important role in activity. However, the selectivity of silica-alumina in producing branched chain olefins only slightly changed by fluorination. In addition, branched chain olefin production was significantly reduced by at least about 50% when the temperature was lowered from 150 ° C to 135 ° C. These data indicate that branched chain olefin productivity is much more sensitive to temperature than the particular catalyst tested. Also, as seen in the last row of the table, branched chain olefin yields decreased by about one third or more when the temperature was lowered from 150 ° C to 135 ° C.

Another way to analyze these data is to compare branched chain olefin productivity at the same olefin conversion. As long as the olefin conversion is associated with benzene conversion during alkylation, the difference in selectivity of branched chain olefin formation is indicative of the expected difference in the nonlinearity of the alkylates. In Table 1, it was shown that at 1-decene conversion of about 30%, fluorinated silica (G) gave much less branched chain olefins than its non-fluorinated counterpart (E). Perhaps this is valid for catalyst A even though a 1-decene conversion of 30% is required at temperatures around 170 ° C.

Example 2

Alkylation of Benzene with 1-decene

Using the catalyst G as a fixed bed, at 500psig 25 (3550kPa) and 2hr ^-l LHSV: benzene 1: To perform the alkylation of benzene by 1-decene, using a feedstock with a non-olefin.

Table 2. Alkylation of Benzene with 1-decene Using Catalyst G]

These data show that temperature has an important effect on linearity and methyl branching in alkylation. In particular, the methyl branching in non-chain alkylates decreased from 64% (2.9 / 4.5) at 120 ° C. to 20% (0.45 / 2.2) at 100 ° C. This data also interprets that 1-decene isomerized in advance to form methyl branched olefins, which in turn alkylate benzene. In addition, the data showed that the catalyst was strongly modified to increase alkylation activity to allow manipulation at lower temperatures.

Example 3

Alkylation of Benzene Using Mixed Olefin Feedstocks: Effect of Cold Temperature on Straightness

As summarized in Table 3, the feedstock described above at 500 psig (3450 kPa) and 2 ^{hr −1} LHSV was used in a benzene: olefin ratio of 25: 1 as the olefin source for alkylation as summarized in Table 3.

Table 3. Effect of Temperature on the Linearity of Alkylates]

In the data, it was found that detergent alkylates formed at any given temperature had the same straightness, whether or not the silica was fluorinated (see results of E and G). However, clays could provide detergent alkylates with somewhat higher straightness, especially at higher temperatures. What distinguishes fluorinated silica-alumina (G) from other catalysts is their increased activity. G had a conversion of 100% even at 120 ° C., while the other two catalysts had only about 70% conversion at that temperature. This is an advantageous example of using a fluorinated silica-alumina catalyst. In particular, it should be noted that the linearity of the alkylate formed at 120 ° C. with G is the same as that formed at 135 ° C. with J, but under these conditions G exhibited a conversion of about 100%, unlike J. .

Example 4

Effect of Fluoride Concentration on Silica-alumina Catalyst

Alkylation of benzene was performed at 135 ° C., 500 psig (3550 kPa), LHSV at 2 ^hr −1, and benzene: olefin ratio of 25: 1, and the results are shown in Table 4. 75:25 silica-alumina with 2.5% fluoride, shown to have the highest activity, was shown to have the highest number of hours at 100% conversion. In addition, the linearity with the exception of non-fluorinated 90:10 silica-alumina was mainly independent of the catalyst.

TABLE 4 Effect of concentration of fluoride on silica-alumina catalyst performance

Claims (6)

Benzene is a fluorinated silica-alumina catalyst having a silica: alumina weight ratio of 1: 1 to 9: 1 and containing 1 to 6% by weight of fluoride at a temperature of 80 to 140 ° C. and a pressure of 1480 to 7000 kPa (200 to 1000 psig). Benzene is reacted with one or more linear monoolefins having 6 to 20 carbon atoms, characterized in that it is reacted with linear monoolefins in an amount such that the molar ratio of benzene: straight monoolefin is from 5: 1 to 30: 1. At least% olefin conversion, at least 85% conversion of olefins to monoalkylbenzenes, and at least 90% linearity to monoalkylbenzene formation. The process of claim 1 wherein the molar ratio of benzene: straight monoolefin is from 8: 1 to 20: 1. The method according to claim 1 or 2, wherein the temperature is 135 ° C or lower. The process of claim 1 or 2 wherein the silica: alumina weight ratio of the catalyst is from 65:35 to about 85:15. The process according to claim 1 or 2, wherein the catalyst contains 1.5 to 3.5% by weight of fluoride. Benzene having from 6 to 20 carbon atoms in the presence of a fluorinated silica-alumina catalyst complex having a silica to alumina weight ratio of 1: 1 to 9: 1 in the alkylation zone under alkylation conditions and containing 1 to 6% by weight of fluoride. Alkylation with one or more linear monoolefins to selectively form monoalkylated benzenes, and monoalkylated benzenes are sulfonated with sulfonating agents under sulfonation conditions in the sulfonation zone to form sulfonic acids of monoalkylated benzenes, A method for producing a biodegradable detergent alkylbenzene sulfonate, characterized by reacting with an aqueous solution of an alkali metal base to form a monoalkylbenzene alkali metal sulfonate.