FR2669033A1 - Polyarylsilsesquioxanes containing at least one sulphonic group, which are grafted onto an inorganic support, their preparations and their applications - Google Patents

Abstract

Compound of the polyarylsilsesquioxane type containing at least one sulphonic group grafted onto an inorganic support, preferably an inorganic oxide such as silica. These compounds are prepared by a sequence of stages comprising a stage of polymer formation, a stage of grafting the polymer onto the support, a sulphonation stage and a stage of modification of the chain ends. These compounds are employed as catalyst especially in acidic catalysis.

Description

The present invention relates to the field of polymers carrying acid groups and grafted on inorganic supports. It relates more particularly to the methods of synthesis and the applications in acid catalysis of these supported polymer compounds.

The compounds according to the invention have good accessibility to the acid sites located on the polymer grafted to the surface of a support. These compounds also have a number of acid sites much higher than that of the corresponding acid mineral products of the prior art, as a result of the amplification provided by the polymer chain. The compounds of the present invention have excellent chemical stability in a wide pH range, excellent dimensional stability and good resistance to attrition and, also, excellent thermal stability which makes it possible to envisage their use, in particular in acid catalysis. , at temperatures up to 300 "C.

dans laquelle M représente un support inorganique choisi dans le groupe formé par les oxydes minéraux, les mélanges d'oxydes minéraux et les oxydes minéraux comportant en surface des groupes hydroxyles et(ou silylalcoxyles de formule -Si-(OR2)3, dans laquelle chacun des groupes R2, indépendamment les uns des autres, représente un groupe alcoyle ayant de préférence de 1 à 5 atomes de carbone ;R1 représente un groupe bivalent de formule =Si-(R3R4) dans laquelle R3 représente un atome d'halogène, un groupe alcoyle ayant de préférence de 1 à 5 atomes de carbone ou un groupe alcoxyle de formule -O-R5 dans laquelle R5 représente un groupe alcoyle ayant de préférence de 1 à 5 atomes de carbone, R4, identique ou différent de R3, représente un groupe alcoyle ayant de préférence de 1 à 5 atomes de carbone ou un groupe alcoxyle de formule -O-R6 dans laquelle R6 représente un groupe alcoyle, identique ou différent de R5 ayant de préférence de 1 à 5 atomes de carbone ; p est un nombre égal à zéro ou 1; Y représente un groupe hydroxyle (-OH) ou une liaison avec le support inorganique ;Y1 et Y2 représentent chacun, indépendamment l'un de l'autre, un atome d'hydrogène ou un groupe monovalent de formule -Si(R7)3 dans laquelle chacun des groupes R7 représente, indépendamment les uns des autres, un groupe alcoyle ayant de préférence 1 à 5 atomes de carbone ; A1 et A2 représentent chacun, indépendamment l'un de l'autre, un groupe aryle comportant de 6 à 30 atomes de carbone, un groupe arylsulfonique, comportant au moins un groupe sulfonique (-S03H), et ayant de 6 à 30 atomes de carbone, ou l'un de ces groupes qui est substitué par au moins un atome d'halogène et/ou par au moins un groupe halogénoalcoyle comportant 1 ou plusieurs atomes d'halogène et ayant de 1 à 5 atomes de carbone et/ou par au moins un groupe nitro (-NO2), et n est un nombre entier d'environ 5 à environ 10 000.More specifically, the invention relates to compounds of the polyarylsilsesquioxane type comprising at least one sulfonic group, grafted onto an inorganic support corresponding to the general formula (1):

in which M represents an inorganic support chosen from the group formed by mineral oxides, mixtures of mineral oxides and mineral oxides having on the surface hydroxyl and (or silylalkoxy) groups of formula -Si- (OR2) 3, in which each R2 groups, independently of each other, represents an alkyl group preferably having from 1 to 5 carbon atoms; R1 represents a bivalent group of formula = Si- (R3R4) in which R3 represents a halogen atom, a group alkyl preferably having from 1 to 5 carbon atoms or an alkoxyl group of formula -O-R5 in which R5 represents an alkyl group preferably having from 1 to 5 carbon atoms, R4, identical or different from R3, represents a group alkyl preferably having from 1 to 5 carbon atoms or an alkoxyl group of formula -O-R6 in which R6 represents an alkyl group, identical or different from R5 preferably having from 1 to 5 carbon atoms ; p is a number equal to zero or 1; Y represents a hydroxyl group (-OH) or a bond with the inorganic support; Y1 and Y2 each represent, independently of one another, a hydrogen atom or a monovalent group of formula -Si (R7) 3 in each of the groups R7 represents, independently of one another, an alkyl group preferably having 1 to 5 carbon atoms; A1 and A2 each represent, independently of one another, an aryl group comprising from 6 to 30 carbon atoms, an arylsulfonic group, comprising at least one sulfonic group (-SO3H), and having from 6 to 30 atoms carbon, or one of these groups which is substituted by at least one halogen atom and / or by at least one haloalkyl group comprising 1 or more halogen atoms and having from 1 to 5 carbon atoms and / or by at least one nitro group (-NO2), and n is an integer from about 5 to about 10,000.

In the context of the present description, the term halogen atom denotes a fluorine, chlorine, bromine and / or iodine atom. Among the compounds of the invention comprising, for example on at least one aryl and / or arylsulfonic group, at least one halogen atom in their molecule, mention may be made of those comprising a chlorine atom and / or a monochloromethyl group of formula ( -CH2CI) and / or a trifluoromethyl group of formula (-CF3).

The mineral oxide used as support usually has a specific surface (Sp) of about I to about 1000 square meters per gram (m2 / g), preferably about 10 to about 500 m2 / g, a total volume of pores ( Vp) from 0.1 to 2 cubic centimeters per gram (cm3 / g), a pore radius, at the maximum of the differential distribution curve of the pore volume as a function of the pore radius, of approximately 100 to approximately 500 nanometers ( nm).

More particularly, the products of the present invention correspond to the general formula (I) above, in which M represents an oxide of one of the elements of groups 2a, 3a, 4a and 4b of the table of the periodic table of the elements ( Handbook of Chemistry and Physics, 63rd edition, CRC, 1982-1983, inside cover page 2). Among the most frequently used mineral oxides, mention may be made of silica, alumina, zirconia, titanium oxides, magnesia and their mixtures such as, for example, silica-aluminas.

The mineral oxide which is preferred to be used as an inorganic support for the compounds of the present invention is silica.

The aromatic polymer carrying the sulphonic acid groups, often called a linear polyarylsilsesquioxane polymer, is attached to the inorganic support, by covalent bond, by at least one of its ends,
The other end or the other ends possibly being free (s) or neutralized (s) by transformation of the terminal groups (-OH) into groups of formula -O-Si- (R7) 3 in which R7 has the definition given above- before. The residual hydroxyl surface groups of the support can optionally also be neutralized by transformation into groups of formula -O-Si (R7) 3, in which R7 has the definition given above.

In the compounds of general formula (I) according to the invention, A1 and A2 most often represent, independently of one another, a phenyl group, a phenylsulfonic group comprising one or more sulfonic groups or one of these groups substituted by at least one halogen atom and / or by at least one halogenomethyl group comprising 1 or more halogen atoms and / or by at least one nitro group; the groups R2 and R7 most often each represent, independently of one another, a methyl or ethyl group, the group R3 most often represents a chlorine atom, a methyl group, an ethyl group, or an alkoxyl group of formula -O-R5 in which R5 represents a methyl or ethyl group and the group R4 most often represents a methyl or ethyl group, or an alkoxyl group of formula -O-R6 in which R6 most often represents a methyl group or ethyl.

One of the characteristics of the compounds of the invention is to have a number of acid sites 10 to 20 times that of the potential acid sites of the support. Thus, in the particular case of a silica with a specific surface 100 m2 / g having initially 5 limol / m2 of hydroxyl sites, that is to say 0.5 millimole per gram (mmol / g) would lead by fixing silane at a capacity (in aromatic nucleus) a little less than half of this, that is to say 0.25 millimoles per gram, as this is for example mentioned by KK Unger in "Porous Silica", Journal of Chromatography Library, n "16, page 260,
Elsevier, 1979, therefore approximately 0.1 milliequivalents per gram (meq / g) of sulfonated aromatic nucleus (i.e. 20 mg of supported reagent), while by fixing on this silica its weight of sulfonated polymer, it is possible to obtain , an acid capacity of 2.39 meq of hydrogen iong.

 It appears that it is not always desirable to fix such an amount of sulfonated polymer for reasons of steric bulk and accessibility to all the sites. One can thus fix for example 0.3 g of sulfonated polymer on 1 g of silica to obtain an effective capacity of 1.1 meq / g, without profound modification of the support, that is to say, by preserving the essential of its mechanical and morphological characteristics. Indeed there is in this case only about one site modified on 50 modifiable hydroxyl sites of the initial silica.

The compound can be obtained by a process comprising the following steps: a) a step of preparing a low molecular weight polymer of polyarylsiloxane type from an aryltrihalosilane and / or an aryltrialcoxysilane, b) a grafting step of a polyarylsiloxane type polymer on a mineral oxide, a mixture of mineral oxides or a mineral oxide having on the surface hydroxyl and / or silylalkoxy groups of formula -Si- (OR2) 3 and / or groups of formula -Si - (R3R4X) in which X is a halogen atom, c) a step of modifying the chain ends of the polyarylsiloxane type polymer by transformation of at least part of the terminal hydroxyl groups into -O-Si- groups (R7 ) 3 and d) a step of sulfonation of at least part of the aryl groups of the polyarylsiloxane type polymer.

The process for preparing the compounds of the present invention can also comprise a step (e) of heat treatment in the presence of alkali or alkaline-earth ions.

We can in particular distinguish several preparation methods during which steps (a), (b), (c), (d) and possibly (e) are carried out in one of the following orders 1) (a), ( b), (c) and (d) 2) (a), (d), (b) and (c) 3) (a), (c), (d), (b) and possibly (c) 4 ) (a), (e), (b), (d) and (c)
Steps (a), (b), (c) and (d) are described below in more detail in connection with the first method. Step (e) is described in detail in connection with the penultimate method.

Method 1
Step (a)
Preparation of a low molecular weight polyarylsilsesquioxane polymer.

This polymer with double-stranded stereoregular structure can be obtained by hydrolysis, by several routes, in particular the following two. The hydrolysis conditions, in either case, influence the molecular weight and structural regularity of the polymers. They are chosen so as to obtain this double chain structure and a high molecular mass, according to the rules well known to those skilled in the art and described for example by JF Brown et al., J.Am.Chem.Soc., Vol. . 82, pages 6194 to 6195, (1960), and by C. Janin, A.

Guyot, Journal de Chimie Physique, pages 1120 to 1124 (1972). The remarkable thermal stability derives on the one hand from the double-stranded structure of the polymer and on the other hand from the stability of the Si-O-Si bonds.

The first route of production is the hydrolysis of an aryltrihalosilane, such as for example an aryltrichlorosilane, in an ethereal medium, for example within ethyl ether, to a polymer of low linear or cyclic molecular mass, or to cyclic terminations.

The second way of obtaining is the acid or basic hydrolysis of an aryltrialcoxysilane, for example an aryltrimethoxysilane. This hydrolysis is carried out under conventional conditions and for example according to the method described by M.M. Sprung, F.O. Guenther, Journal of Polymer Science, 28, page 17 (1958).

Step (b)
Grafting of low molecular weight polyarylsilsesquioxane, obtained according to one of the routes described in step (a), on an inorganic support.

The inorganic support, previously dried, is placed in the presence of a solution in a solvent (for example toluene) of the low molecular weight polymer obtained in step (a), and left at reflux for a period of approximately 30 minutes to about 10 hours. The reaction between the hydroxyl groups of the polymer and of the support is accompanied by reactions causing rearrangement of the chains and an increase in the molecular mass. The ungrafted polymer is then extracted, for example with toluene, in a soxhlet. After reaction, the mineral oxide beads onto which the polymer has been grafted, are filtered and dried under reduced pressure and at moderate temperature, for example for two hours under 100 pascal (Pa), at 50 ° C.

Step (c)
During this step, a modification is carried out simultaneously or separately of the ends of the chains of the polyarylsilsesquioxane polymer attached to the inorganic support and the neutralization of the residual hydroxyl sites of this support.

This silylation reaction, for example with hexamethyldisilazane (HMDS), has the effect, on the one hand, of protecting the terminal groups of the polymer from subsequent reactions, on the other hand, of replacing the hydroxyl sites of the support with —O groups. -Si- (R7) 3 thus ensuring better thermal and chemical stability of the final product.

Step (d)
Sulfonation of the grafted and modified polyarylsilsesquioxane obtained in step (c).

Many sulfonating agents can be used, in particular chlorosulfonic acid, sulfuric acid or sulfuric anhydride (SO3) alone or in complexes or adducts, in solution in halogenated hydrocarbons. This step is carried out under conventional conditions which are, for example, those described in the book by EE Gilbert, "Sulfonation and Related Reactions", published by
Wiley (1965) or by JP Planche, A. Revillon and A. Guyot, Journal of Polymer
Science, Part A: Polymer Chemistry, Vol. 26, pages 429 to 444 (1988) and Vol.

28, pages 1377 to 1386 (1990). Depending on the sulfonating agent used and the conditions chosen, different sulfonation rates are obtained.

Method 2
Step (a) is repeated in an identical manner to that described in connection with method 1. The resulting polymer is then subjected to sulfonation under the general conditions described above for step (d). This sulfonation can be carried out in a halogenated aromatic hydrocarbon, such as for example dichlorobenzene, in which the polymer is dissolved. The sulfonated polymer is then grafted onto an inorganic support according to the method described in connection with step (b) of method 1, then modified according to the procedure described for step (c) of method 1.

Method 3
According to this method, the preparation steps are carried out according to the conditions described for each of them in conjunction with method 1 and by successively carrying out step (a) then step (c) of modification of the polymer chain ends, followed by step (d) of sulfonation, and finally step (b) of grafting the sulfonated polymer obtained in step (d) on the inorganic support. The product thus grafted can be optionally modified according to the procedure described in step (c) in conjunction with method 1 so as to at least partially neutralize the residual hydroxyl sites of the inorganic support.

Method 4
According to this method, the low molecular weight polymer obtained according to one of the routes described for step (a), in conjunction with method 1, is subjected to a step (e) of heat treatment in the presence of alkali or alkaline ions. - earthy, preferably potassium ions. This treatment is for example carried out in a solvent for the polymer (for example toluene). It is for example carried out at reflux of the solvent for a few hours approximately.

During this treatment, a rearrangement of the polymer also takes place into a polymer of higher molecular mass, which, depending on the conditions, is then from about 5,000 to about 5,106 g / mol. The polymer obtained at the end of step (e) is then grafted onto an inorganic support under the conditions described above in conjunction with step (b) of method 1, then sulfonated under the conditions of step (d) of this method 1 and finally modified under the conditions of step (c) of this method 1.

When the inorganic support is a mineral oxide, it can be modified beforehand by a treatment making it possible to fix a more or less significant quantity of halosilane, of haloalkylsilane or of alkoxysilane so as to obtain a support containing the silylalkoxy groups of formula - Si- (OR2) 3 and / or groups of formula -Si- (XR3R4). The use of this support, thus modified allows better control of the grafting of the polymer. The treatment of the support, for example dichlorodimethylsilane, chloromethylphenyltriethoxysilane or chloropropyltriethoxysilane makes it possible to fix on the support a molecule, called reactive, which retains after its fixing on said support a residual function which reacts easily with the silanol ends of the polymer which one wants to graft.

Method 5
The compounds of general formula (I) according to the invention can also be obtained from a silylaryl monomer which is sulfonated then which is polymerized and which is grafted onto the inorganic support. The chain ends of the polymer and optionally the residual hydroxyl sites of the support can be neutralized as described above for step (c) of method 1.

The present invention also relates to the use of the compounds of general formula (I) described above and obtained for example by one of the methods described above as catalyst and in particular in acid catalysis.

The following examples illustrate the invention without limiting its scope. Examples 1 to 7 illustrate the synthesis of the compounds and Examples 8 to 13
The application in acid catalysis of the compound obtained in Example 2.

Example 1 Etapea.

30 ml of phenyltrichlorosilane and 100 ml of ethyl ether are introduced into a 500 ml (ml) flask fitted with a condenser. The polymer is formed by hydrolysis at a temperature of 20 ° C. by adding 20 ml of deionized water to the flask dropwise, with stirring, until cloudiness appears and the stirring for 2 hours. The ethereal solution is separated, which is washed 3 times with 100 ml of water and this solution is dried over sodium sulfate (Na2SO4), then the ether is removed by evaporation, before drying for 2 hours at 20 "C, under reduced pressure of 100 Pa.

The polymer is in the form of white grains and is characterized by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopies.

 It is dissolved in tetrachlorethylene. The proton NMR Bruker is locked to the dioxane signal. The ratio of the integrals of the aliphatic and aromatic hydrogen signals leads to the average number n of constituent units of the polymer chain. Here it is 13, that is to say a number-average molecular mass (Mn) of 3,400, which is confirmed by the determination by chromatography on permeable gel, which also indicates a polymolecularity index (Mw / Mn) of 2.2 (Mw represents the weight average molecular mass).

The IR spectrum of powder of the 1% tablet polymer in potassium bromide (KBr) shows the characteristic absorption bands at the following wave numbers: Si-OH: 3619 cm-1 (free silanol), 3401 cm- 1 (bound silanol);
Aromatic CH: 3070 and 3049 cl ~ 1; Si-C = C 1594, 1430 (vibration of the aromatic nucleus), 738, 696 cm-1; Si-O-Si: 1130-1000 cm-l.

Step (b)
The grafting of the polymer onto a surface silica 400 m2 / g, with a density of hydroxyl sites 3.3 iimol / m2, is carried out as follows: 10 grams of silica, previously dried 4 hours at 1200C under vacuum, are placed in a 250 ml flask fitted with a condenser. 50 ml of dry toluene and 5 g of the polymer obtained in step (a) are introduced into the flask. It is refluxed for 4 hours and the grafted silica beads are filtered off, which is dried for 3 hours under reduced pressure from 100 Pa to 50 "G. The ungrafted polymer (1 g) is extracted with toluene in a soxhlet. The number average molecular weight of the extracted polymer, determined by chromatography on permeable gel is 25,000.

Step (c)
The modification of the product obtained in step (b) by neutralization of the silanol groups is carried out by addition of 3.8 ml of hexamethyldisilazane to 1 g of product suspended in 10 ml of chloroform, under a stream of nitrogen, for 2 hours at 20 C. The chloroform is then removed by evaporation. Dried under reduced pressure of 100 Pa, at 50 C for 2 hours.

Step (d)
The sulfonation of the polyphenylsilsesquioxane grafted onto silica obtained in step (c) is carried out as follows: 10 9 of this product and 50 ml of chloroform are introduced into a 100 ml flask, fitted with a condenser and an ampoule of addition containing 10 ml of chlorosulfonic acid which is introduced dropwise into the flask. The suspension is then heated to 50 ° C. and this temperature is maintained for 2 hours 30 minutes. The excess acid is then neutralized by fractional addition of 10 ml of methanol. The resulting product is washed with methanol, with water then again with methanol. This product is then dried under vacuum for 2 hours under a pressure of 100 Pa. This product corresponds to a compound defined by the general formula (I), the structure of which is confirmed by the nuclear magnetic resonance spectrum (NMR) of Carbon 13 (13C) and that of silicon 29 (29Si). The 13C NMR spectrum highlights the meta sulfonation of the aromatic nucleus (resonance at -142 ppm) and that of 29Si shows by the peaks at - 68 and at - 77 ppm of the bonds of the polymer to silica. The acid capacity, measured, of this compound is 1.97 meq · g. The measurement of the acidity of Hammet Ho of this compound is carried out by determination of hydrolysis heat. It is compared to acidity determined by a colorimetric method on sulfuric acid solutions at different concentrations.

In the examples of applications below, Amberlyst 15 will be considered as a reference for a known compound whose Hammet constant is - 2.3 and the acid capacity of 4.36 meq / g. The determination of Ho is carried out on 5 g of compound. The compound in this example has a Ho acidity of - 3.7.

Example2
The procedure described in Example 1 for steps (a), (b) and (c) is repeated and step (d) of sulfonation of the grafted polyphenylsilsesquioxane is carried out as follows 10 g of the product obtained in step ( c) are suspended in 50 ml of trifluoro-1,1,2-trichloro-1,1,2-ethane placed in a 250 ml flask fitted with an addition funnel containing 10 ml of a solution molar of
SO3 dissolved in trifluoro-1, 1, 2-trichloro-1, 1, 2-ethane. The SO3 solution is added dropwise and the mixture is left to react for 1 hour at a temperature of 20 "C.

The resulting compound is filtered through a frit and washed thoroughly with methanol, then dried under vacuum (100 Pa) for 2 hours. The acid capacity measured is 1.7 meq / g and the Hammet Ho constant of the compound is - 4.7.

Example3
In this example, the procedure described in Example 1 for steps (a), (b), (c) and (d) is repeated, but a support obtained as follows is used: 10 g of silica with a specific surface 400 m2 / g, density of hydroxyl sites 3.3 Fmol / m2 are treated with 2 g of chloromethylphenyltriethoxysilane in toluene at reflux. The product is dried. The fixing yield is 25%. The polymer obtained in step (a) is then grafted onto this support during step (b) as follows. A solution of the polymer in 20 ml of dimethylformamide (DMF) is brought into contact with the support. 10 g of potassium tert-butanolate are added at 0 ° C., then the temperature is brought to 20 "C. and left to react for 2 hours. The product is recovered by filtration, dried under reduced pressure from 100 Pa to 50" C. and then modified according to the procedure described in step (c) of Example 1 and sulfonated according to the procedure described in step (d) of Example 1. The acid capacity of the compound obtained is 1.2 meq / g.

Example 4
The procedure described in Example I is repeated by carrying out the steps in the following order step (a) of preparation of a low molecular weight polymer then step (d) of sulfonation, followed by step (b) of grafting and finally step (c) of modification of the silanol groups. The silica used in this example has a specific surface of 90 m2 / g and a density of hydroxyl sites of 5.3 limol / m2. The acid capacity of the compound obtained is 1.05 meq / g.

Examples
Example 4 is repeated using the same support but step (d) of sulfonation is carried out in the presence of dichlorobenzene and the support used to graft the sulfonated polymer is that obtained according to the procedure described in Example 3. The capacity acid of the compound obtained is 0.4 meo / g.

Example 6
The procedure described in Example 1 for step (a) is repeated. The polymer obtained at the end of this step (a) is treated with hexamethyldisilazane so as to neutralize its silanol ends. 1.7 ml of hexamethyidisilazane are added to 2 g of polymer dissolved in 10 ml of chloroform, under a stream of nitrogen, for 2 hours, at 20 ° C. The solvent is removed by evaporation. It is dried under reduced pressure of 100 Pa, at 50 ° C for 2 hours.

After treatment with HMDS, the ends of protected chains comprise trimethylsilyl groups and show the following characteristic infrared bands: -Si- (CH3) 3 at 1250 cm-1, doublet at 844 and 755 cm-1; the initial wide band eSi-OH around 3600 cm-1 has very significantly decreased.

The product thus obtained is then sulfonated according to the procedure described in Example 1 for step (d). This sulfonation is carried out on the solution of the polymer in chloroform.

This polymer is then grafted onto the silica described in Example 1 by following the procedure described in this example for step (b). The silica used in this example is that described in connection with Example 4. The acid capacity of the compound obtained is 0.6 meq / g.

Example 7
The procedure described in Example 1 for step (a) is repeated. 10 g of the polymer obtained at the end of this step are dissolved in 10 ml of toluene containing 0.1 g of potassium hydroxide. The rearrangement of the polymer is carried out by bringing this solution to reflux for 1 hour. The water formed is removed by azeotropic distillation and the solution thus concentrated is poured into an excess of methanol. The polymer then has a number-average molecular mass measured by chromatography on a permeable gel of 70,000. The grafting of the polymer onto a silica with characteristics identical to that used in Example 1 is carried out under the conditions described in step (b ) of this example 1 by bringing 10 g of silica into contact with 4 g of polymer dissolved in 30 ml of toluene. The product obtained is then treated according to the procedure described in step (d) of example 1 and then according to that of step (c) of this example.

Example 8
Esterification of acetic acid with isopropanol.

25 ml of acetic acid and 0.3 g of the product prepared in Example 2 above are introduced as catalyst, then 2 ml of isopropanol. The kinetics of esterification is determined by analysis by gas chromatography.

The conversion of isopropanol is 90% in 100 minutes, against 50% under the same conditions with Amberlyst 15.

The activity reduced to meq / g is higher than that of Amberlyst 15.

Example 9 Alkylation of Ortho-Cresol with 1-Dodecene
The ortho-cresol (9.4 g), 1.4 g of the compound prepared in Example 2 above and 0.1 ml of octadecane (internal standard) are placed in a 500 ml flask and brought to 1 20 C. 6.3 ml of 1-dodecene are added. The cresoVolefin molar ratio is two. The conversion of 1-dodecene is 30% in 25 minutes and it is 53% after 180 minutes.

The monoalkylation selectivity, measured by gas chromatography is 82%, against 14% in the case of the use of Amberlyst 15 as a catalyst.

Example 10
Synthesis of MTBE by reaction between isobutylene and methanol.

The reaction mixture, under nitrogen, of 1.54 mole of isobutylene, 1.61 mole of methanol (molar ratio close to 1) and 4.57 moles of toluene, contained in a tank, is sent, using a pump to the total flow rate of 0.1 ml / min, on a thermostatically controlled column, containing 3 grams of the compound prepared in Example 2 above, used as a catalyst. A cooling device makes it possible to collect the eluates. The instant conversion, determined by analysis by gas chromatography, is 75% methanol and 77% isobutylene. It remains constant over time for the duration of the test, ie 1 week.

Claims (10)

1) Compound of the polyarylsilsesquioxane type comprising at least one sulfonic group, grafted onto an inorganic support corresponding to the general formula (1):

 in which M represents an inorganic support chosen from the group formed by mineral oxides, mixtures of mineral oxides and mineral oxides having on the surface hydroxyl and / or silylalkoxy groups of formula -Si- (OR2) 3, in which each R2 groups independently of each other, represents an alkyl group, R1 represents a bivalent group of formula = Si- (R3R4) in which R3 represents a halogen atom, an alkyl group or an alkoxyl group of formula -O-R5 in which R5 represents an alkyl group, R4 represents an alkyl group, identical or different from R3 or an alkoxyl group of formula -O-R6 in which R6 represents an alkyl group, identical or different from R5, p is a number equal to zero or 1, Y represents a hydroxyl group or a bond with the inorganic support, y1 and Y2 each represents, independently of one another, a hydrogen atom or a group -Si (R7) 3 in which each of the groups R7 represents, independently of each other, an alkyl group, A1 and A2 each represent independently of one another, an aryl group having 6 to 30 carbon atoms, an arylsulfonic group having one or more sulfonic groups, and having 6 to 30 carbon atoms, or one of these groups which is substituted by at least one halogen atom and / or by at least one haloalkyl group comprising 1 or more halogen atoms and having from 1 to 5 carbon atoms and / or by at least one nitro group and n is a number whole from about 5 to about 10,000. 2) Compound according to claim 1 corresponding to the general formula (I), in which M represents a mineral oxide of one of the elements of groups 2a, 3a, 4a and 4b of the table of the periodic table of the elements. 3) Compound according to claim 1 or 2 corresponding to the general formula (I) in which M represents an inorganic oxide chosen from the group formed by silica, alumina, zirconia, titanium oxides, magnesia and silicas - aluminas. 4) Compound according to one of claims 1 to 3 corresponding to the general formula (I) in which M represents silica. 5) Compound according to one of claims 1 to 4 corresponding to the general formula (I) in which M represents a mineral oxide having a specific surface of approximately 1 to approximately 1000 m2 / g, a total pore volume of 0 , 1 to 2 cm3 / g and a pore radius, at the maximum of the differential distribution curve of the pore volume as a function of the pore radius, of approximately 100 to 500 nm. 6) Compound according to one of claims 1 to 5 corresponding to the general formula (I) in which A1 and A2 independently of one another represent a phenyl group, a phenylsulfonic group comprising one or more sulfonic groups, or l '' one of these groups which is substituted by at least one halogen atom and / or by at least one halogenomethyl group comprising 1 or more halogen atoms and / or by at least one nitro group, the groups R2 and R7 each represent independently of one another, a methyl or ethyl group, the group R3 represents a chlorine atom, a methyl group, an ethyl group, or an alkoxyl group of formula -O-R5 in which R5 represents a methyl group or ethyl and the group R4 represents a methyl group or an ethyl group, or an alkoxyl group of formula -O-R6 in which R6 represents a methyl or ethyl group. 7) A method of preparing a compound according to one of claims 1 to 6 characterized in that it comprises the following steps: a) a step of preparing a low molecular weight polymer of polyarylsiloxane type from an aryltrihalosilane and / or an aryltrialcoxysilane, b) a step of grafting a polymer of the polyarylsiloxane type onto a mineral oxide, a mixture of mineral oxides or a mineral oxide comprising on the surface hydroxyl and / or silylalkoxy groups of formula -Si - (OR2) 3 and / or groups of formula -Si- (R3R4X) in which X is a halogen atom, c) a step of modifying the chain ends of the polyarylsiloxane type polymer by transformation of at least one part of the terminal hydroxyl groups into groups -O-Si- (R7) 3 and d) a step of sulfonation of at least part of the aryl groups of the polymer of polyarylsiloxane type. 8) A preparation method according to claim 7 wherein there is further carried out a step e) of heat treatment in the presence of alkali ions and / or alkaline earth ions, preferably potassium ions. 9) Preparation process according to claim 7 or 8 comprising steps (a), (b), (c), (d) and optionally (e) carried out in one of the following orders 1) (a), (b ), (c) and (d) 2) (a), (d), (b) and (c) 3) (a), (c), (d), (b) and possibly (c) 4) (a), (e), (b), (d) and (c) 10) Use of a compound according to one of claims 1 to 6 or of a compound prepared according to one of claims 7 to 9 as catalyst.