FR2662438A1 - Process for the production of alkylbenzenes using catalysts based on dealuminated zeolite Y - Google Patents

Abstract

Process for the production of an alkylbenzene in which, in a reaction region, benzene is reacted with a charge containing an aliphatic monoolefin and/or an aliphatic alcohol in the presence of a catalyst based on a dealuminated zeolite Y with an overall Si/Al atomic ratio greater than 4, preferably of between 8 and 70, the product obtained is then fractionated so as to separately collect a first fraction containing unconverted benzene, a second fraction containing a monoalkylbenzene and a third fraction containing a polyalkylbenzene, the third fraction then being, at least in part, recycled to the said reaction region where it reacts with benzene in the presence of the said catalyst in order to be, at least in part, transalkylated, and at least one monoalkylbenzene is collected.

Description

 The present invention relates to a process for producing at least one alkylbenzene by alkylating benzene with monoolefin (s) and / or alcohol (s).

 It has already been proposed, for carrying out this reaction, the use of zeolites in H form, in particular ZSM5 (EP-0104729).

More recently, other zeolites have been put forward, in particular certain mordenites, alone or mixed with faujasite (US Pat. No. 3,436,432), optionally with a Group VIII metal deposited thereon (US Pat. No. 5,351,004). Japanese Patent JP 58216128 and
JP 58159427 advocate mordenites alone, low Si / Al ratio (4.5 to 5), containing metal ions such as Mg, K, Ca, or H form (JP 041670).

 Even more recently, a French patent application (national registration number 88/140099) reports satisfactory results obtained in the presence of dealuminated mordenites having a global Si / Al atomic ratio of between 30 and 80.

 It is an object of the invention to improve the alkylation yield to mono-alkyl benzenes by reducing the proportion of the polyalkylbenzenes formed.

 According to the process of the invention, benzene is reacted in a reaction zone with a feedstock containing at least one compound selected from the group consisting of aliphatic mono-olefins and aliphatic alcohols in contact with at least one catalyst based on a dealuminized zeolite Y, with an overall Si / Al atomic ratio greater than 4, preferably between 8 and 70 (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 mono-alkyl benzene (or mono-alkyl benzene moiety) and a third fraction containing at least one polyalkylbenzene (or polyalkylbenzene moiety), which moiety is then, at least partly, recycled to said reaction zone or it therefore reacts with benzene in contact with said catalyst, that is to say the catalyst mentioned above based on a zeolite Y dealuminum ee, in order to be at least partly transalkylated (transalkylation reaction), and at least one monoalkylbenzene is collected.

 The recycled portion of the third fraction is preferably substantially free of heavy alkyl aromatics (these may be removed by fractionation) and preferably contains substantially at least one dialkylbenzene.

 The invention is characterized in particular 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 based on dealuminated zeolite Y with a Si / Al atomic ratio greater than 4, preferably between 8 and 70.

 Preferably, the first fraction containing unconverted benzene after the alkylation reaction is at least partially recycled to said reaction zone: thus, at least a portion of the benzene reacting with at least a portion of the third fraction (or poly-alkylbenzene fraction) recycled is unconverted benzene during the alkylation reaction, thus unconverted benzene from said first fraction.

 Thus, the mono-alkylbenzenes obtained according to the invention come, on the one hand, from the alkylation reaction of benzene (and thus from the mono-alkylbenzene fraction obtained), and, on the other hand, from the trans-alkylation reaction of the polyalkylbenzenes produced during said alkylation reaction of benzene.

The aluminized Y zeolite is employed alone or in admixture with a binder or matrix generally selected from the group formed by clays, aluminas, silica, magnesia, zirconia, titanium oxide, boron oxide and any combination thereof. at least two of the aforementioned compounds such as silica-alumina, silica-magnesia, etc. All known methods of agglomeration and shaping are applicable, such as, for example, extrusion, pelletization, coagulation drops etc
Thus, in the process according to the invention, at least one dehydrated zeolite Y catalyst with an overall Si / Al atomic ratio greater than 4, preferably between 8 and 70, generally containing from 1 to 100%, preferably from 20 to 70, is used. 98% and, for example, 40 to 98% by weight of said dealuminated Y zeolite 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. We can for example refer to US Patent 4,738o9401
The zeolite Y used in the present invention is an acidic zeolite HY characterized by various specifications, whose determination methods 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 (determined on the zeolite calcined at 11000 C); a crystalline parameter has a unit cell size of less than 24.55 x 10 μm and, preferably, between 24.39 x 10 -10 m and 24.21 x 10 -10 m; a specific surface determined by the BET method. greater than about 300 m 2 / g and preferably greater than about 550 m 2 / g a water vapor adsorption capacity at 25 ° C, for a partial pressure of 2.6 torr, greater than about 0.5% and, preferably, greater than about 3%
The various preceding characteristics can be measured by the following methods - the overall Si / Al atomic ratio can be measured by analysis
when the amounts of aluminum become low, by
example less than 2%, for more precision, it is appropriate
to use a method of determination by absorption spectrometry
atomic;; - the mesh parameter can be calculated from the diagram of
X-ray diffraction according to the method described in the form
ASTM D 3.942-80. It is clear that to perform this calculation
correctly, 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 liquid nitrogen
and calculated according to the classical BET method.
are pretreated, before measurement, at 500 ° C under a dry nitrogen sweep, - water recovery percentages (or adsorption capacity of
water vapor) are for example determined by means of
classic gravimetry. The sample is pretreated at 400 ° C under
primary vacuum, then brought to a stable temperature of 25 ° C.
then a water pressure of 2.6 torr, which corresponds to a
P / Po ratio of about 0.10 (ratio of partial pressure
of water admitted into the apparatus and the saturation vapor pressure of
water at a temperature of 25 ° C).

 It has been discovered in the present invention that stabilized Y zeolites having the above specifications have outstanding properties for the production of monoalkylbenzenes by alkylation of benzene with mono-olefin (s) and / or alcohol (s).

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

Generally, the Y-Na zeolite from which the zeolite Y used in the invention is prepared has an atomic ratio.
Si / Al overall ranging from about 1.8 to 3.5; it will be necessary first to lower the weight content of sodium to less than 3% and, preferably, less than 2.5%; Y-Na zeolite also has a specific surface area of about 750 to 950 m 2 / g.

 The benzene alkylation and transalkylation reactions of the polyalkylbenzenes are usually carried out in the liquid phase, in the supercritical phase or in the gas phase, in the presence of at least one catalyst based on the dealuminated zeolite Y defined above, arranged in a bed ( s), at a temperature of about 50 to 450 ° C (preferably about 150 to 350 ° C), at a pressure of 1 to 10 MPa (preferably 2 to 7 MPa), with a liquid hydrocarbon flow rate (space velocity) of about 0.5 to 50 volumes per volume of catalyst per hour, and with a molar ratio of benzene / (monoolefin (s) and / or alcohol (s)) of between 1 and 20 (preferably between 5 and 15).

 The mono-olefin and / or the alcohol or the mixture of mono-olefin (s) and / or starting alcohol (s) may come from any known source, for example steam cracking units, catalytic cracking or coking with regard to mono-olefins, alcoholic fermentation or hydration of olefins with regard to alcohols.

 Although it is possible to carry out the invention with a mixture of mono-olefins and / or a mixture of alcohols, it is preferred, in order to facilitate the fractionation between mono-alkylbenzenes and polyalkylbenzenes, to operate with a single mono olefin, for example ethylene, propene, n-butene or isobutene (more generally with an aliphatic monoolefin having, for example, from 2 to 20 carbon atoms), or with ur. single alcohol, for example ethanol, isopropanol, n-butanol or isobutanol (more generally with an aliphatic alcohol having, for example, 2 to 20 carbon atoms), or with a monoolefin-alcohol mixture having the same number of carbon atoms, for example an ethylene-ethanol, propene-isopropanol, n-butene-n-butanol or isobutene-isobutanol mixture.

 The single figure illustrates a particular embodiment of the invention.

 An aliphatic mono-olefin (line 1) is mixed with an aliphatic alcohol of the same number of carbon atoms (line 2), the resulting mixture (line 3) being then mixed, on the one hand, with fresh benzene (conduct 4) and, on the other hand, with a mixture (line 5) of benzene and dialkylbenzenes, the benzene coming, through line 17, from the top of a first fractionating column 16 and the dialkylbenzenes coming from, by driving 23, the head of a third fractionation column 22. The overall mixture (or charge) obtained is then sent via line 6 into the charge-effluent heat exchanger 7, then, via line 9, into the alkylation reactor 10, after a possible passage in the preheating furnace 8.At the outlet of the reactor 10, the effluent is sent through the pipe 11 to the heat exchanger 7, and then through the pipe 12 to a condenser-decanter 13 where an aqueous phase is separated, which is withdrawn by line 14, and a hydrocarbon phase. This is then sent via line 15 to a first fractionation column 16 (in the case where the feedstock contains no aliphatic alcohol, the effluent leaving the heat exchanger 7 is directly sent to the first fractionation column 16). At the top of this first fractionation column 16, the excess benzene which has not reacted and which is then recylated, after mixing with the dialkylbenzenes, by the pipe 23, the head of a third fractionation column 22, to the reactor inlet 10 by the pipe 5. At the bottom of this first fractionation column 16, a mixture is collected which is sent by the pipe 18, to a second fractionation column 19. At the top of this second fractionation column 19, a pure mono-alkylbenzene is collected which is sent via line 20 to storage. At the bottom of this second fractionation column 19, draws a a mixture of poly-alkylbenzenes which is sent, via line 21, to a third fractionation column 22. At the top of this third fractionation column 22, dialkylbenzenes are collected via line 23, which is then recycled after mixture with the benzene from the pipe 17 of the head of the first fractionation column 16 to the inlet of the reactor 10 via the pipe 5. At the bottom of this third fractionation column 22, the heavy alkylaromatics are withdrawn. are removed from the circuit by line 24, these heavy alkylaromatic may possibly be used as fuel in the preheating furnace 8.

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

EXAMPLE 1 Preparation of a Catalyst A.

 NaY zeolite of formula NaA102 (SiO2) 2.5 is used as raw material.

This zeolite has the following characteristics - overall Si / Al atomic ratio: 2.5 - crystalline parameter a: 24.69 x 10 m - vapor adsorption capacity
water at 25 ° C (at P / Po = 0.1): 26% - specific surface area: 880 m2 / g.

 It is subjected to five consecutive exchanges in ammonium nitrate solutions of 2M concentration, at a temperature of 95 ° C., for a time of 1.5 hours, and with a volume ratio of solution per weight of zeolite equal to 8 cm 3 The sodium content of the zeolite NaNH4Y obtained is 0.95% This product is then rapidly introduced into a preheated oven at 770 ° C. and left for 4 hours in a stagnic atmosphere (stabilizing treatment). The zeolite is then subjected to two exchanges with solutions of ammonium nitrate of concentration 2 M so that its sodium content goes down to 0.2% by weight. Its overall Si / Al atomic ratio is then 3.15, its crystalline parameter has elemental mesh of 24.38 × 10 -m, its specific surface area of 625 m2 / 9, its water recovery capacity of 11.3 / 0 (P / Po = 0.1). The zeolite thus obtained is shaped by extrusion with alumina. The extrudates obtained are then dried and then calcined at around 500 ° C. A catalyst A based on said zeolite is obtained, containing 80% by weight of said zeolite and 20% by weight of alumina.

EXAMPLE 2 Preparation of a Catalyst B.

 The starting NaY zeolite is subjected to the same five exchanges and to the same stabilizing treatment as in Example 1. After stabilization, instead of making exchanges with ammonium ions, an acid treatment is carried out under the following conditions: ratio between the volume of 3N nitric acid solution and the solid weight is 9 cm 3 / g, the temperature is 95 ° C. and the duration of the treatment is 3 hours, then another treatment under the same conditions is carried out, but with 0.5N nitric acid solution.

 The zeolite obtained has a sodium content of 0.2%, an overall Si / Al atomic ratio of 28, a crystalline parameter a of the elementary mesh of 24.24 × 10 10 m, a specific surface area of 770 m 2 / g , a water recovery capacity of 5.0% (P / Po = 0.1).

 The shaping, drying and calcining steps are carried out under the same conditions as those described in Example 1, so as to obtain a catalyst B based on said zoolite, containing 80% by weight of said zeolite and 20% by weight of said zeolite. % by weight of alumina.

EXAMPLE 3 Preparation of a catalyst C.

 The starting NaY zeolite is subjected to the same five exchanges and to the same stabilizing treatment as in Example 1.

 After stabilization, instead of exchanging with ammonium ions, an acidic treatment is carried out using a 2N nitric acid solution under the following conditions: the ratio between the volume of nitric acid solution 2N and the weight of solid is 12 cm3 / g, the temperature is 95 ° C and the duration of the treatment of 3 hours Then another treatment under the same conditions is carried out, but with a solution of 6N nitric acid.

The zeolite obtained has a sodium content of 0.2%, an overall Si / Al atomic ratio of 75, a crystalline parameter α of elemental mesh of 24.20 × 10 10 μm, a specific surface area of 700 m 2 / g, a capacitance of water recovery of 1.1%
P / Po = 0.1).

 The shaping, drying and calcining steps are carried out under the same conditions as those described in Example 1, so as to obtain a catalyst C based on said zoolite, containing 80% by weight of said zeolite and 20% by weight of said zeolite. % by weight of alumina.

EXAMPLE 4
The three catalysts A, B and C prepared in Examples 1, 2 and 3 are each tested, in a reactor, for alkylation of benzene with ethylene under the following operating conditions - temperature: 270 ° C., pressure: 4 MPa, - weight hourly rate of benzene equal to 3 times the weight of
catalyst, benzene / ethylene molar ratio: 9.6.

 The filler has the following composition by weight - ethylene: 3.60% - benzene: 96.40%.

 At the outlet of the reactor, the products obtained have the weight composition shown in Table 1. It can be seen that it is preferable to work with the catalysts recommended by the invention, that is to say that it is necessary to use dealuminated Y zeolites whose overall Si / Al atomic ratio is greater than 4 and preferably between 8 and 70 (case of catalyst B). Indeed, zeolites Y having an overall Si / Al atomic ratio of less than 8, more particularly 4 (case of catalyst A), are slightly more active, but much less selective and unstable. Y zeolites having an atomic ratio Si Overall AI greater than 70 (case of catalyst C) are still usable; nevertheless, if they are a little more selective, they are less active, which could lead, in an industrial unit, either to work at a higher temperature with shorter cycle times, or to reduce the space velocity which would be detrimental to the economy of the process.

EXAMPLE 5
Catalyst B, prepared in Example 2, is used to transalkyl diethyl benzenes in the presence of an excess of benzene under the following operating conditions - temperature: 270 ° C., pressure: 4 MPa, - weight hourly flow rate of benzene equal to 3 times the weight of the catalyst.

 The filler has the following weight composition - benzene: 98.93% - diethylbenzenes: 1.07%.

TABLE 1

<tb> CATALYSTS <SEP> J <SEP> I <SEP> I
<tb><SEP> I <SEP> I <SEP> I <SEP> I
<tb> CONSTITUENT <SEP> I <SEP><SEP> A <SEP> A <SEP> | <SEP> B <SEP> J <SEP> C <SEP> J
<tb> l (% <SEP> weight) <SEP> I <SEP> I <SEP> I <SEP> J
<tb><SEP> I <SEP> ~~~~~ <SEP> J <SEP> ~~~~~ <SEP> J <SEP> ~~~~~ <SEP> I <SEP> ~~~~ ~
<tb> CHARGE <SEP> I <SEP> J <SEP> I <SEP> I
<tb> J <SEP> ethylene <SEP> J <SEP> 3.60 <SEP> J <SEP> - <SEP> J <SEP> - <SEP> 1 <SEP> 1.42 <SEP> 1
<tb> Benzene <SEP> 1 <SEP> 96.40 <SEP> 1 <SEP> 87.24 <SEP> 1 <SEP> 86.62 <SEP> 1 <SEP> 90.50 <SEP> 1
<tb> Toluene <SEP> I <SEP> - <SEP> J <SEP> 0.03 <SEP> J <SEP> - <SEP> J <SEP> - <SEP> J
<tb> Ethylbenzene <SEP> J <SEP> - <SEP> 1 <SEP> 10.94 <SEP> 1 <SEP> 12.73 <SEP> 1 <SEP> 7.79 <SEP> 1
<tb> IMethylethylbenzenes <SEP> J <SEP> - <SEP> J <SEP> 0.04 <SEP> J <SEP> - <SEP> I <SEP> - <SEP> I
<tb> JDiethylbenzenes <SEP> | <SEP> I <SEP> - <SEP> J <SEP> 1.16 <SEP> 1 <SEP> 0.53 <SEP> 1 <SEP> 0.27 <SEP> J
<tb> JMethyldiethylbenzenes <SEP> I <SEP> - <SEP> J <SEP> 0.03 <SEP> J <SEP> - <SEP> | <SEP> 0.03 <SEP> |
<tb> ITriethylbenzenes <SEP> | <SEP> I <SEP> | <SEP> 0.31 <SEP> 1 <SEP> - <SEP> 1 <SEP> 0.02 <SEP> 1
<tb> JHC <SEP> aromatic <SEP> heavy <SEP> | <SEP> r <SEP> | <SEP> 0.25 <SEP> 1 <SEP> 0.12 <SEP> 1 <SEP> - <SEP> I
<tb> J <SEP> J <SEP> I <SEP> J <SEP> ~~~ <SEP> J <SEP> ~~~
<tb><SEP> J <SEP> JID <SEP> I <SEP> 100 <SEP> 1100 <SEP> J
<tb> I <SEP> I <SEP> I <SEP> ~~~~~ <SEP> J <SEP> ~~~~~ <SEP> I <SEP> ~~~~~ <SEP> J <SEP > ~~~~~
<tb> VITALS <SEP> FROM <SEP> CONVERSION <SEP> BY <SEP> J <SEP> J <SEP> J <SEP> J
<tb> PASS <SEP> J <SEP> J <SEP> J <SEP> PASS
<tb> J <SEP> J <SEP> J <SEP> J
<tb> ethylene <SEP> | <SEP> I <SEP> J <SEP> 10O <SEP> E <SEP> J <SEP> 100 <SEP>% <SEP> j <SEP> 61.6 <SEP>% <SEP> ss
<tb> Benzene <SEP> ss <SEP> 1 <SEP> 9.5 <SEP>% <SEP> 1 <SEP> 10.1% <SEP> 1 <SEP> 6.1 <SEP>% <SEP> I
<tb><SEP> I <SEP> J <SEP> I <SEP> J
<tb> 1 <SEP> 1 <SEP> J <SEP> ~~~~~ <SEP> J <SEP> ~~~~~ <SEP> J <SEP> ~~~~~ <SEP> J <SEP > ~~~~~
<tb> SELECTIVITIES <SEP> ss <SEP> J <SEP> J <SEP> J
<tb> JEthylbenzene <SEP> I <SEP> I <SEP> I <SEP> I
<tb> i <SEP> x <SEP> 1001 <SEP> 1 <SEP> 80.3 <SEP>% <SEP> 1 <SEP> 93.4 <SEP>% <SEP> J <SEP> 94.4 <SEP>% <SEP> J
<tb> ethylene <SEP> transformed <SEP> J <SEP> J <SEP> I <SEP> I
<tb> I <SEP> J <SEP> I <SEP> J
<tb> JEthylbenzene <SEP> J <SEP> J <SEP> J <SEP> J
<tb> I <SEP> x <SEP> 1001 <SEP> 1 <SEP> 88.8 <SEP>% <SEP> ≈ <SEP> 96.3 <SEP>% <SEP> J <SEP> 97.1 <SEP>% <SEP> J
<tb> Benzene <SEP> transforms <SEP> J <SEP> J <SEP> I <SEP> J
<tb><SEP> J <SEP> J <SEP> I <SEP> J
<Tb>
The product obtained has the following weight composition - benzene: 98.37% - ethylbenzene: 1.56% - diethylbenzenes: 0.07%
100%
The catalyst B recommended by the invention is therefore very active and very selective both for the alkylation reaction of benzene with ethylene and for the transalkylation reaction of diethylbenzenes.

EXAMPLE 6
Using the catalyst B, prepared in Example 2, the operating conditions described in Examples 4 and 5, and according to the procedure diagram specified in the single figure, that is to say in particular by combining the alkylation reactions benzene by ethylene and trans-alkylation of diethylbenzenes, the following results are obtained:
- selectivity to ethylbenzene relative to benzene
transformed: 99.5%
- selectivity to ethylbenzene relative to ethylene
transformed: 99.8%
These values correspond to specific consumptions of 246.7 kg of ethylene and 739.5 kg of benzene per tonne of ethylbenzene produced.

EXAMPLE 7
Catalyst B, prepared in Example 2, is used to alkylate benzene with ethanol under the following operating conditions - temperature: 290 ° C, - pressure: 4 MPa, - weight hourly flow rate of (benzene + ethanol) equal to 3 times the weight
catalyst, benzene / ethanol molar ratio: 9.

The filler has the following composition by weight - benzene: 93.85% - ethanol: 6.15%
The product obtained has the following weight composition - ethylene 0.02% - benzene: 83.78% - ethanol: - ethylbenzene: 12.95% - diethylbenzenes: 0.63% - triethylbenzenes 0.01% - HC heavy aromatics: 0 , 20% - water: 2.41%
100%
The following results are thus obtained: benzene conversion rate: 10.7% - ethanol conversion rate: 100% - ethylbenzene selectivity compared to
with transformed benzene: 95.4% - selectivity to etylbenzene compared
with converted methanol: 91.5%
EXAMPLE 8
Catalyst B, prepared in Example 2, is used to produce cumene by alkylation of benzene with propene, according to the process diagram corresponding to the single figure, that is to say in particular by combining the reactions of benzene alkylation and transalkylation of diisopropylbenzenes. The operating conditions are the following: - temperature: 220 ° C., - pressure: 4 MPa, - hourly weight rate of benzene equal to 2.5 times the weight of the
catalyst, benzene / propene molar ratio: 8.4.

The filler has the following composition by weight - propane: 0.31% - propene: 6% - benzene: 93.69%
The product obtained has the following weight composition - propane: 0.31% - propene - benzene: 82.65% - cumene: 16.93% - diisopropylbenzenes: 0.08% - heavy residue: 0.03%
100%
The following results are thus obtained: selectivity in cumene with respect to
transformed benzene: 99.7% - cumene selectivity with respect to
converted propene: 98.8%
EXAMPLE 9
Catalyst B, prepared in Example 2, is used to produce cumene by alkylation of benzene with isopropanol, according to the process scheme corresponding to the single figure, that is to say, in particular by combining the reactions of alkylation of benzene and transalkylation of diisopropylbenzenes under the following operating conditions - temperature: 270 ° C., - pressure: 4 MPa, - hourly hourly feed rate (benzene + isopropanol) equal to 3 times the
catalyst weight, benzene / isopropanol molar ratio: 8.8.

The filler has the following composition by weight - benzene: 92% - isopropanol: 8%
The product obtained has the following weight composition - propene: 0.05 SO - benzene: 81.98% - isopropanol - water: 2.40% - cumene: 15.32% - diisopropylbenzenes: 0.15% - heavy residue: 0.10%
100%
The following results are thus obtained: cumene selectivity with respect to the converted benzene: 99.40% - cumene selectivity with respect to the converted isopropanol: 95.8%
EXAMPLE 10
Catalyst B, prepared in Example 2, is used to produce cumene by alkylation of benzene with a propene-isopropanol mixture, according to the process diagram corresponding to the single figure, that is to say in particular by combining the benzene alkylation and transalkylation reactions of diisopropylbenzenes, under the following operating conditions - temperature: 2500 ° C., - pressure: 4 MPa, - hourly hourly flow rate (benzene + isopropanol)
equal to 3 times the weight of the catalyst, molar ratio benzene / isopropanol + propane: 8.4.

The filler has the following composition by weight - propane: 0.15% - propane: 3.13% - benzene: 92.73% - isopropanol: 3.99%
The product obtained has the following weight composition - propane: 0.15% - propene: 0.03% - benzene: 81.98% - isopropanol - water: 1.20% - cumene: 16.47% - diisopropylbenzenes: 0, 11% - heavy residue: 0.06%
100%
The following results are thus obtained: selectivity in cumene with respect to
transformed benzene: 99.6% - cumene selectivity with respect to
the amount of propene + isopropanol converted: 97.8%

Claims (11)

 transalkylated, and at least one monoalkylbenzene is collected.  presence of said catalyst to be at least partially  to said reaction zone where it reacts with benzene in  third fraction being then, at least partly, recycled  fraction containing at least one poly-alkylbenzene, said  containing at least one mono-alkylbenzene and a third  fraction containing unreacted benzene, a second fraction  product obtained so as to separately collect a first  overall Si / Al atomic ratio greater than 4, then the  of at least one catalyst based on a zeolite Y dealuminated with  aliphatic mono-olefins and aliphatic alcohols in the presence  containing at least one compound selected from the group consisting of  react, in a reaction zone, benzene with a charge  1. A process for producing at least one alkylbenzene in which one The process according to claim 1 wherein said catalyst is  based on a dealuminated Y zeolite of Si / Al atomic ratio  overall between 8 and 70. 3. Method according to one of claims 1 and 2 wherein said  first fraction is at least partly recycled to the said zone  of reaction. 4. Method according to one of claims 1 to 3 wherein the part  recycled from said third fraction is substantially free  of heavy alkyl-aromatics and essentially contains at least one di-alkyl benzene. 5. Method according to one of revendicetions 1 to 4 wherein said  the dealuminated Y zeolite also has the characteristics  following  - a sodium content of less than 0,25% by weight  a crystalline parameter has a unit cell less than 24.55 × 10 m  a specific surface area of greater than about 300 m2 / g  a water vapor adsorption capacity at 25 ° C., for a  partial water pressure of 2.6 torr, greater than about 0.5  %. 6. Method according to one of claims 1 to 4 wherein said  the dealuminated Y zeolite also has the characteristics  following  - a sodium content of less than 0.25% by weight,  a crystalline parameter has elementary mesh between  24.39.10 10 and 24.21.10 10 m,  a specific surface area greater than about 550 m 2 / g,  a water vapor adsorption capacity at 25 ° C., for a  water partial pressure of 2.6 torr, greater than about 3%. 7. Method according to one of claims 1 to 6 wherein said  catalyst additionally contains a matrix selected from the group  formed by clays, aluminas, silica, magnesia,  zirconia, titanium oxide, boron oxide and any combination  at least two of the above compounds. 8. Method according to one of claims 1 to 7 wherein said  catalyst is arranged in fixed bed (s). 9. Method according to one of claims 1 to 8 wherein said  charge contains a compound consisting of a mono-olefin  aliphatic or an aliphatic alcohol or a mixture of a  aliphatic mono-olefin and an aliphatic alcohol having the same  number of carbon atoms. 10. Method according to one of claims 1 to 9 wherein each  aliphatic mono-olefin is selected from ethylene, propene,  n-butene and isobutene and each aliphatic alcohol is chosen  among methanol, isopropanol, n-butanol and isobutanol. 11. Process according to one of claims 1 to 10 for the production of cumene from benzene and a compound selected from the group consisting of propene, isopropanol and a mixture of propene and isopropanol.