FR2697246A1 - Prodn of phenyl=alkane(s) - by using catalyst based on modified zeolite Y - Google Patents

Abstract

The prodn. of 2-, 3-, 4-, 5- and 6-phenyl alkanes, by alkylation of benzene using at least one 9-16C linear olefin in the presence of a solid zeolite catalyst. The catalyst comprises a matrix and a de-aluminised HY zeolite contg. hardly any extra-cellular Al, and having a Na content less than 0.25%, a cell parameter less than 24.55x10xpower-10 m; and a BET surface area greater than 300 m2/g. The process is carried out at 1-10 MPa and a temp. less than 300 deg.C, spatial velocity of 0.5-50 and a benzene:olefin(s) molar ratio of 1-20. USE/ADVANTAGE - The phenyl-alkanes obtainable are used in the formulation (after sulphonate) of biodegradable detergents. The present invention overcomes safety and disposal problems which are incurred in the usual techniques using HF or AlCl3-based catalysts. The latter techniques also involve difficulties in sepn. of catalyst from the reaction prods. The new catalysts are very active, resistant to de-activation and give selectivities similar to those obtd. in classical processes.

Description

 The present invention relates to a process for producing phenylalkanes by alkylating benzene by means of linear olefin (s) comprising from 9 to 16 carbon atoms per molecule, more particularly from 10 to 14 carbon atoms per molecule, in presence of at least one dealuminized Y zeolite catalyst.

 The phenylalkanes obtained according to the invention constitute compounds for the formulation, after sulphonation, of biodegradable detergents.

 Currently, bases for biodegradable detergents rely heavily on linear alkylbenzenes. The production of this type of compound is growing steadily, reaching around 650000 tonnes / year, for example in Western Europe. One of the main properties sought for these compounds, after the sulphonation step, is, in addition to their detergency, their biodegradability. To ensure maximum biodegradability, the alkyl group must be linear and long, the distance between the sulfonate group and the terminal carbon of the linear chain must be maximal. The most useful benzene alkylating agents are linear C 8 -C 16 and preferably C 10 -C 14 olefins.

 The linear alkylbenzenes obtained by alkylation of benzene with linear olefin (s) are prepared today by two major processes.

 The first process is licensed by UOP and uses, during the alkylation stage of benzene, hydrofluoric acid as an acid catalyst. The second method is licensed by ARCO Technology Inc. and uses a Friedel-Craft type catalyst, in particular based on AlCl3. These two processes lead to the formation of 2-, 3-, 4-, 5- and 6-phenylalkanes.

 The main disadvantage of these methods is related to environmental constraints. The UOP process, based on the use of hydrofluoric acid poses severe safety problems on the one hand and waste reprocessing on the other hand. The ARCO process raises the classic problem of processes based on Friedel-Craft catalysts, in this case the problem of rejects; indeed for this type of process, it is necessary to neutralize the effluents with a basic solution at the reactor outlet. To these various disadvantages are added for both processes the difficulties associated with the separation of the catalyst from the products of the reaction.

 These various constraints explain the interest of developing a process for the alkylation of benzene by linear olefins in the presence of a solid catalyst making it possible to obtain selectivities similar to those obtained in the two processes described herein. -before.

The prior art essentially states the use of catalysts having geometric selectivity properties and leading to improved selectivity to 2- and 3-phenylalkanes. They do not make it possible to obtain distributions of phenylalkanes similar to those obtained with
HF or AIC13. Said catalysts having geometric selectivity properties consist of zeolites. Thus, US-A-4301317 claimed a series of zeolites including: cancrinite, gmelinite, mordenite, offeretite and ZSM-12. These zeolites are, in particular, characterized in that their pore opening is between about 6 and about 7 in diameter (1 Å = 10-10 m).

Y zeolites which have a pore opening close to 7.4 Å do not fall within the scope of US Pat. No. 4,301,317. As regards the use of Y zeolites, EP-160.144 claims the use of poorly crystallized Y zeolites (crystallinity of between 30 and 80%), the patent
US-A-5,036,033 claims the use of Y-zeolites rich in ammonium cations [content greater than 250 ppm calculated as (NH4) 2O].

 We have discovered that the use of dealuminated Y zeolites with an overall Si / Al atomic ratio of greater than 4, preferably of between 8 and 70 and even more advantageously of between 15 and 25, and containing no extraluminal aluminum species. network, present, in alkylation of benzene with linear olefin (s) comprising from 9 to 16 carbon atoms per molecule, more particularly from 10 to 14 carbon atoms per molecule, catalytic performances higher than those of catalysts described in the prior art. These new catalysts are in particular both very active, very resistant to deactivation and lead to selectivities in phenylalkanes similar to those obtained in conventional processes using HF or AlCl 3 as a catalyst.

 The dealuminated zeolite Y is used alone or in admixture with a binder or a matrix generally chosen from the group formed by clays, aluminas, silica, magnesia, zirconia, titanium oxide, boron oxide and any combination of at least two such oxides as silica-alumina, silica-magnesia. All known methods of agglomeration and shaping are applicable, such as, for example, extrusion, pelletization, drop coagulation, etc.

Thus, in the process according to the invention, at least one catalyst based on zeolite Y desaluminized with an Si / Al atomic ratio greater than 4, preferably between 8 and 70, and generally containing from 1 to 100%, preferably from 1 to 100%, is preferably used. at 98% and, for example 40 to 98% of said zeolite
Y is aluminized and 0 to 99%, preferably 2 to 80%, and, for example, 2 to 60% by weight of a matrix.

 The dealuminated Y zeolites and their preparation are well known. For example, reference may be made to US-A-4,738,940.

The zeolite Y used in the present invention is an acidic zeolite
HY characterized by different specifications, whose methods of determination are specified in the following text: an overall Si / Al atomic ratio greater than 4, preferably between 8 and 70; a sodium content of less than 0.25% by weight; a crystalline parameter aO of the unit cell less than 24.55 × 10 -10 m and, preferably, between 24.39 × 10 -10 m and 24.2 × 10 -10 m; a specific surface area determined by the BET method of greater than about 300 m 2 / g and preferably greater than about 450 m 2 / g; a water vapor adsorption capacity at 250 ° C, for a partial pressure of 3.46 mbar, greater than about 0.5%, and more preferably greater than about 3%.

 The proportion of extra-network aluminum species of the dealuminated Y zeolite used in the present invention is very low or even zero; the content of aluminum species is such that no signal attributable to such species can be detected, either by 27 Al nuclear magnetic resonance using the magic angle rotation technique, or by infrared spectroscopy in the hydroxyl group region; more quantitatively, the ratio of the intensity of the signals corresponding to the non-framework aluminum species (extra lattice) to the intensity of the signals corresponding to the aluminum framework species is less than 0.05, for the two characterization techniques.

 The various preceding characteristics can be measured by the following methods - the overall Si / Al atomic ratio can be measured by chemical analysis.

When the amounts of aluminum are low, for example less than 2%, for greater accuracy, it is appropriate to use an atomic adsorption spectrometry assay method.

- the mesh parameter can be calculated from the diagram of
X-ray diffraction according to the method described in the form
ASTM D 3942-80. I1 is clear that to perform this calculation correctly it
The crystallinity of the product must be sufficient.

the specific surface is for example determined by measurement of
the nitrogen adsorption isotherm at the temperature of the liquid nitrogen and
calculated according to the classical BET method The samples are pretreated,
before the measurement, at 5000 C under a dry nitrogen sweep.

- percentages of water uptake (or vapor adsorption capacity
of water) are for example determined using a conventional apparatus of
gravimetrically. The sample is pretreated at 4000 C under primary vacuum, then
brought to a stable temperature of 250 C. Then a pressure is admitted
of water of 3.46 mbar, which corresponds to a ratio P / Po of about 0.10
(ratio of the partial water pressure allowed in the appliance to the
saturation vapor pressure of water at 25 C).

 It has been found in the present invention that the dealuminated Y zeolites having the above-mentioned specifications have remarkable properties for the production of phenylalkanes by alkylation of benzene with mono-olefins.

 These zeolites are for example manufactured, generally from an NaY zeolite, by an appropriate combination of two basic treatments: (a) a hydrothermal treatment which associates temperature and partial pressure of water vapor, and (b) a treatment acid by, preferably, a strong mineral acid and concentrated.

 Generally, the zeolite NaY from which the zeolite Y used in the invention is prepared has an overall Si / Al atomic ratio of between about 1.8 and 3.5; it will be necessary beforehand to lower the weight content of sodium to less than 3% and, preferably, less than 2.5%. The reduction of the sodium content can be carried out by ion exchange of the NaY zeolite in ammonium salt solutions (nitrate, sulfate, oxalate, etc.) with an ammonium concentration of between 0.01 and 10 N, at a temperature of between 10 and 1800 ° C. (possibly under autogenous pressure exchange) for a period greater than about 10 minutes. The NaY zeolite also has a specific surface area of approximately 750 to 950 m 2 / g.

According to a preferred variant of the process of the invention, benzene is reacted in a reaction zone with a feedstock containing at least one linear olefin comprising from 9 to 16 carbon atoms per molecule, preferably from 10 to 14 atoms. of carbon per molecule, in contact with a catalyst based on a dealuminated zeolite Y having the characteristics defined previously (alkylation reaction), and then the product obtained is fractionated so as to separately collect a first fraction containing unconverted benzene a second fraction containing at least one unconverted linear C 8 -C 16 olefin (preferably C 1 -C 10 -C 14), a third fraction containing 2-, 3-, 4-, 5- and 6-phenylalkanes and a fourth fraction containing at least one poly-alkylbenzene (or poly-alkylbenzene moiety), which is then, at least in part,
recycled to said reaction zone where it therefore reacts with benzene in contact with said catalyst, to be at least partly transalkylated (transalkylation reaction), and a mixture of 2-, 3-, 4-, 5- and 6phenylalkanes.

 This variant of the invention is therefore particularly characterized by the fact that the alkylation and transalkylation reactions take place jointly in the same reaction zone (that is to say) in the same reactor) in the presence of the same catalyst. .

 Preferably, the first fraction containing unconverted benzene is at least partially recycled to said reaction zone. Likewise, preferably, the second fraction containing at least one linear olefin Cg-C16 (usually C10-C14) unconverted is at least partly recycled to said reaction zone.

 The recycled portion of the fourth fraction preferably contains substantially at least one dialkylbenzene and is preferably substantially free of heavy alkyl aromatics which may optionally be removed by fractionation.

 The process according to the present invention can be carried out at a temperature below 3000 C, for example less than 600 C, at a pressure of 1 to 10 MPa, with a liquid hydrocarbon flow rate (space velocity) of approximately 0.5 at 30 volumes per volume of catalyst and per hour and with a molar ratio benzene / olefin (s) of between 1 and 20.

 The following examples illustrate the invention without, however, limiting its scope.

Example 1 Preparation of a catalyst not in accordance with the invention
A large pore mordenite from the company Tosoh is used in the sodium form referenced TSZ600NAA. Its chemical formula, in the anhydride state, is Na, AlO2 (SiO2) 5.1 and its sodium content is 5% by weight.

 100 g of this powder are refluxed at 1000 ° C. for 2 hours in a solution of 4 M ammonium nitrate with a V / P ratio equal to 4 cm 3 / g. This cation exchange operation is repeated 3 times.

The weight content of sodium of the product obtained is about 500 ppm.

 This product is then subjected to an acid attack using an aqueous solution of 4.5 N nitric acid, the product is refluxed in the aqueous solution of nitric acid for 2 hours, with a ratio V / P equal to 4 cm3 / g. After acid attack, the product is washed with water.

 The mordenite thus obtained has a weight content of sodium equal to 25 ppm, an overall Si / Al atomic ratio of 40, a microporous volume of 0.272 cm 3 / g.

 The mordenite is then mixed with an alumina gel (80% by weight of mordenite and 20% by weight of alumina gel). The mixture obtained is formed into extrudates of diameter equal to about 1.8 mm per passage through a die. The extrudates are then dried in an oven at 120 ° C overnight, and then calcined in dry air to about 5500 ° C.

 This catalyst is noted A.

Example: Preparation of catalyst B according to the invention
NaY zeolite of the formula NaAlO 2 (SiO 2) 2.5 is used as raw material. This zeolite has the following characteristics - overall Si / Al atomic ratio: 2.5 - crystalline parameter aO: 24.69 10-10 m - water vapor adsorption capacity at 25 C (P / Po = 0.1 ): 26% - specific surface area: 880 m2 / g.

 It is subjected to five successive exchanges in ammonium nitrate solutions of concentration 2 M, at a temperature of 950 C, for a time of 1.5 hours, and with a volume ratio of solution by weight of zeolite equal to 8 cm3 / g. The sodium content of the NH4Y zeolite obtained is 0.95%. This product is then quickly introduced into a preheated oven at 7700 C and left for 4 hours in a static atmosphere (stabilizing treatment). The zeolite is then subjected to an acid treatment under the following conditions: the ratio between the volume of 3N nitric acid solution and the weight of solid is 9 cm 3 / g, the temperature is 950 ° C. and the duration of the treatment of 3 hours. Then another treatment under the same conditions is carried out, but with a 0.5 N nitric acid solution.

 The zeolite obtained has a sodium content of 0.2%, a global Si / Al atomic ratio of 28, a crystalline parameter aO equal to 24.24 × 10 -10 m, a specific surface area of 770 m 2 / g and a capacity of water recovery of 5% (at P / Po = 0.1).

 The zeolite thus obtained is shaped by extrusion with alumina (80% of zeolite and 20% of alumina). The extrudates obtained are then dried and calcined at 5500 C.

 the catalyst thus obtained, catalyst according to the invention, is denoted B.

Example3
The two catalysts, A and B, are each tested for alkylation of benzene by dodecene-1, under the following operating conditions - temperature: 50 C - pressure: 4 MPa - hourly flow rate of the liquid charge equal to 3 times the volume of the catalyst benzene / dodecene-1 mol ratio: 5.5
The results obtained are shown in Table 1.

Table 1

<tb><SEP> Catalyst <SEP> A <SEP> (No <SEP> Compliant) <SEP> B <SEP> (Compliant)
<tb> Composition <SEP> of <SEP> the <SEP> load
<tb> (% <SEP> weight)
<tb> Benzene <SEP> 71.7 <SEP> 72.3
<tb> Dodecene-1 <SEP> 28.3 <SEP> 27.7
<tb> Composition <SEP> of the <SEP> product
<tb> obtained <SEP> (% <SEP> weight)
<tb> 2-phenylalkane <SEP> 77.34 <SEP> 26.92
<tb> 3-phenylalkane <SEP> 10.83 <SEP> 20
<tb> 4-phenylalkane <SEP> 0.98 <SEP> 19
<tb> 5-phenylalkane <SEP> 0 <SEP> 11.5
<tb> 6-phenylalkane <SEP> 0 <SEP> 11.48
<tb> Didocecylbenzene <SEP> 10.10 <SEP> 10
<tb> Residue <SEP> heavy <SEP> 0.75 <SEP> 1.1
<Tb>
It can thus be observed that only the catalyst containing a dealuminated zeolite Y (catalyst B) makes it possible to obtain a relatively homogeneous phenylalkane distribution and relatively close to that generally obtained with the processes using HF or AIC13 as catalyst. Catalyst A produces essentially 2- and 3-phenylalkanes.

Claims (12)

1.- Process for the simultaneous production of 2-, 3-, 4-, 5-, 6-phenylalkanes by  alkylation of benzene using at least one linear olefin  comprising from 9 to 16 carbon atoms per molecule, in the presence of a  zeolitic solid catalyst, characterized in that the catalyst is  consisting of a matrix and dealuminated HY zeolite, not containing  virtually no extra-lattice alumina species  sodium content of less than 0.25% by weight, a crystalline parameter of  the elemental mesh is less than 24,55.10-1 m, a specific area  BET greater than 300 m2 / g, and that said process is carried out at a  pressure of 1 to 10 MPa, a temperature below 300 C, a  space velocity of 0.5 to 50 and a molar ratio of benzene to olefin (s)  between 1 and 20. 2. The process according to claim 1, wherein the linear olefin (s)  contains from 10 to 14 carbon atoms per molecule. 3. Method according to one of the preceding claims, wherein the  matrix is chosen from the group formed by clays, aluminas,  silica, magnesia, zirconia, titanium dioxide, boron oxide and their  combinations. 4. Method according to one of the preceding claims, wherein the  Si / Al ratio is between 8 and 70. 5.- Method according to one of the preceding claims, wherein the  Si / Al ratio is between 15 and 25. 6. Method according to one of the preceding claims, wherein the  weight content of zeolite in the catalyst is between 20 and  98%. 7.- Method according to one of the preceding claims, wherein the  weight content of zeolite in the catalyst is between 40 and  98%. 8. A process according to one of the preceding claims, wherein the  crystalline parameter of the elementary mesh is between  24.39.10-10 m and 24.21.10'10 m. 9.- Method according to one of the preceding claims, wherein the  specific surface is greater than 450 m2 / g. 10. A process according to one of the preceding claims, wherein the  product obtained at the end of the alkylation zone is split into one  first fraction containing unconverted benzene, a second  fraction containing at least one unconverted linear olefin, a  third fraction containing the phenylalkanes and a fourth  fraction containing at least one polyalkylbenzene, said fourth  fraction being at least partly recycled to the alkylation zone. 11. The process according to claim 10, wherein the first fraction is  at least partly recycled to the alkylation zone. 12. A process according to one of claims 10 or 11, wherein the second  fraction is at least partly recycled to the alkylation zone.