WO2014096721A1

WO2014096721A1 - Method for preparing functionalised polyorganosiloxanes

Info

Publication number: WO2014096721A1
Application number: PCT/FR2013/053191
Authority: WO
Inventors: Emmanuel POUGET; Jean-Marc Frances
Original assignee: Bluestar Silicones France Sas
Priority date: 2012-12-21
Filing date: 2013-12-19
Publication date: 2014-06-26
Also published as: FR3000070B1; FR3000070A1

Abstract

The invention concerns a method for preparing a functionalised polyorganosiloxane comprising a step of hydrosilylating a chlorohydrosilane compound (A) with an unsaturated compound (B) comprising at least one alkene function and/or an alkyene function, the hydrosilylation step being catalysed by a photocatalyst selected from among the polyoxometalates, in order to obtain a functionalised chlorosilane compound (C), followed by a step for the hydrolysis and condensation of a composition comprising at least one functionalised chlorosilane compound (C) in order to obtain at least one linear or cyclic oligomer (D), and finally a step for the polymerisation of a composition comprising at least one oligomer (D) in order to obtain a composition comprising a polyorganosiloxane (E).

Description

Process for the preparation of

functionalized polyorganosiloxanes

FIELD OF THE INVENTION The present invention relates to the field of silicones, and more specifically to the preparation of functionalized silicones.

BACKGROUND

The term "silicone" is commonly used to refer to polysiloxane-type polymers which comprise several unitary units connected to one another by forming Si-O-Si (silicon-oxygen-silicon) chains. In a polysiloxane, each silicon atom may be connected to 1, 2, 3 or 4 oxygen atom (s), and the valency of the silicon atom may be supplemented with organic substituents. We then commonly speak of polyorganosiloxanes. Conventionally, polyorganosiloxanes are produced in two stages. Firstly, organohalosilanes are converted by hydrolysis and condensation to oligo-organosiloxanes of linear or cyclic structure. The technical processes involving the hydrolysis and condensation reaction of organohalosilanes are conventionally continuous and are industrially proven. This is described, for example, in patent documents EP 0 876 419 and EP 0 998 519. These oligomers can then be polymerized so as to lengthen the polymer chain, and optionally be crosslinked, to form polyorganosiloxanes. The processes for the preparation of polyorganosiloxanes by cyclic and linear oligosiloxane polymerization are also widely used in industry, in particular according to the "Ring-Openinig Polymerization" (ROP) polymerization method. Anglo-Saxon).

The most commonly prepared polyorganosiloxanes are those whose organic substituents are methyl groups. However, it is also desired to have polyorganosiloxanes having other types of substituents. The presence of organic substituents of various kinds, including, for example, chemical functions of interest, has an influence on the chemical and physical properties of a polyorganosiloxane. It is for example well known to functionalize a polyorganosiloxane with vinyl functions, to give this compound reactive properties.

Methods for preparing polyorganosiloxanes having, in addition to saturated or aromatic radicals, unsaturated radicals such as allyl or vinyl have been described in the literature for a long time. French patent FR 927 641 describes methods for obtaining linear polyorganosiloxanes having vinyl groups statistically distributed in the middle of the chain. French patent FR 1 132 048 describes a method for obtaining linear polyorganosiloxanes having vinyl groups at the end of the chain. Finally, French patent FR 1,561,922 describes a method for obtaining other types of linear polyorganosiloxanes having vinyl groups distributed in the middle of the chain. All of these methods use vinylchlorosilane compounds as the starting material. Such compounds can themselves be classically prepared by hydrosilylation of hydrogenochlorosilane compounds by catalysis (see for example French patent FR 1 390 999).

One of the difficulties encountered in the process for preparing such functionalized polyorganosiloxanes is to achieve the desired functionalization in a controlled manner and with good yields. Indeed, certain functions may require the use of reagents that interact with the undesired non-functional polyorganosiloxane by generating by-products. The functionalization rate and the position of these functions can be difficult to control. For these reasons, the choice of the nature of the functions of interest that can be grafted onto the polyorganosiloxane and the position of these functions can be limited and the functionalization of polyorganosiloxanes with certain functions can be difficult or impossible.

It is in this context that the inventors have sought to develop a method for synthesizing functionalized polyorganosiloxanes different from those existing, and solving at least one of the problems of the processes of the prior art. The researchers therefore set themselves the goal of proposing a process for the production of functionalized polyorganosiloxanes whose functionalization rate and position of functions are controlled with a very wide variety of accessible functions. In addition, it is desired that the functionalized polyorganosiloxane production process does not include a step requiring the use of expensive catalyst, difficult to supply, difficult to handle and / or toxic.

BRIEF DESCRIPTION OF THE INVENTION

These objectives have been achieved by the present invention, which relates to a process for preparing a functionalized polyorganosiloxane comprising the following steps: a) a step of hydrosilylation of a chlorinated hydrogenosilane compound (A) of general formula (I) :

Z _a HCl _b Si (I)

in which - Z represents a monovalent radical different from a hydrogen atom and a chlorine atom, and

a and b are integers, with 0, 1 or 2, b being 1, 2 or 3 and a + b = 3;

with an unsaturated compound (B) comprising at least one alkene function and / or an alkyne function, of general formula (II) or (III):

R R

\ /

C = C

Wherein R ¹ , R ² , R ³ and R ⁴ represent a monovalent radical; R ³ R ⁴ (il) R - C≡C - R ² (m);

said hydrosilylation being catalyzed by a photocatalyst selected from polyoxometalates, to obtain a functionalized chlorinated silane compound (C) of general formula (IV):

ZaClbYSi (IV)

in which - Z, a and b are the same as those of the general formula (I)

Y is a functional group of general formula (V) or (VI): C-CH

R ^{3 Nr} (V) - CR = CHR ² (VI),

where R ¹ , R ² , R ³ and R ⁴ have the above meanings; b) a step of hydrolyzing and condensing a composition comprising at least one functionalized chlorinated silane compound (C) of general formula (IV) obtained in the result of step (a) to obtain at least one linear or cyclic oligomer (D) comprising at least two units of formula (VII):

Z _to YSiO (( _3-a ) / 2) (VII)

in which - Z and a are the same as in general formula (I)

Y is the same as in the general formula (IV); and c) a step of polymerizing a composition comprising at least one oligomer (D) obtained at the end of step (b) so as to obtain a composition comprising a polyorganosiloxane (E) comprising at least said unit (VII ).

The method for preparing functionalized polyorganosiloxanes according to the present invention thus comprises a first step in which the chlorosilane hydrogenated compounds are functionalized by one or more functions of interest by hydrosilylation. These functionalized chlorinated chlorosilane compounds then serve as precursors for the monomers of the functionalized polyorganosiloxanes.

DETAILED DESCRIPTION OF THE INVENTION

It is specified that, throughout this description, the expression "understood between ... and ..." should be understood as including the boundaries quoted.

The present invention therefore relates to a process for the preparation of functionalized polyorganosiloxanes comprising a step (a) of hydrosilylation, a step (b) of hydrolysis and condensation and a step (c) of polymerization.

In a hydrosilylation reaction, a compound comprising at least one unsaturation reacts with a compound comprising at least one hydrogen atom bonded to a silicon atom. This reaction can for example be described by the reaction equation (1) in the case of alkene-type unsaturation:

- S i i -H + \ C = C / "► -S 1 i- C1- CH /

(1) I / II \ or by the reaction equation (2) in the case of an alkyne unsaturation: - Si-H + - C≡C - Si- C = CH

(2) I I I

Hydrosilylation thus makes it possible to bind siloxanes, and in particular silicones, comprising Si-H units, with compounds having at least one alkene or alkyne-type initiation, for example silicones comprising Si-vinyl units. The hydrosilylation reactions are conventionally carried out by catalysis. For example in the French patent FR 1,390,999, the hydrosilylation of hydrogenochlorosilane compounds is conducted by platinum catalysis. Platinum catalysis is, moreover, also used for the hydrosilylation of siloxanes, and in particular silicones, comprising Si-H units, with compounds having at least one alkene or alkyne-type initiation, for example silicones comprising units. Si-vinyl. The publication of Vekki's DA ("Hydrosilylation on Photoactivated Catalyst", Russian Journal of General Chemistry, 2011, 81, 7, 1480-1492) discloses photoactivatable catalysts for hydrosilylation of C = C, C≡C and C = 0 bonds. .

In the process of the present invention, the hydrosilylation reaction is photocatalized by a polyoxometallate, commonly referred to as POM. The use of POM as a catalyst has already been described in the literature. The publication of D. Tzirakis et al. "Decatungstate as efficient photocatalysts in organic chemistry" (Chemical Society Reviews, 2009, 38, 2609-2621) describes in particular the photochemical properties of POM, and especially decatungstate, and their use as a photocatalyst. This publication describes the use of decatungstate for the creation of carbon-carbon bonds by homolytic breaking of carbon-hydrogen bonds, for oxidation in the presence of oxygen and for the degradation of organic pollutants. More recently, the researchers Jacques Lalevée, Nicolas Blanchard, Mohamad-Ali Tehfe and Jean Pierre Fouassier have described for the first time in a publication entitled "Decatungstate (Wio032 ^4" ) / Silane: a New and Promising Radical Source Under Soft Light Irradiation " (Macromolecular Rapid Communications, 2011, 32, 838-843) that decatungstate could be used as a photocatalyst to form silyl radicals from silanes, and the photopolymerization of epoxides was presented as a concrete use of this property. application in hydrosilylation has been considered. POMs are anionic aggregates (or "cluster"), consisting of at least 3 transition metal oxoanions that share their oxygen atoms, and together form a structured three-dimensional network.

POMs can be described by the general formula [X _r M _s O _t ] ^{p ~} in which

X represents a hydrogen atom or an atom selected from B, Al, Si, P, S, Ga,

Ge, As, Ce and Sb;

M represents a transition metal;

O represents the oxygen atom;

r represents an integer which may be 0, 1 or 2;

s represents an integer ranging from 3 to 20;

t represents an integer ranging from 6 to 62; and

p represents an integer greater than or equal to 1, preferably ranging from 1 to 10.

This general formula also includes the hydrated forms of the anionic aggregates, although these are not explicitly represented.

In this general formula, all the atoms represented by M, and possibly all the atoms represented by X if the symbol r is equal to 2, may be identical or different.

A POM therefore contains transition metals M. The transition metal of the POM can be chosen from the elements of groups 4, 5, 6 and 7 of the periodic table, preferably from the elements of groups 5 and 6. The metal of transition may be preferably selected from the group consisting of vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo) and tungsten (W), so more preferred in the group consisting of vanadium (V), niobium (Nb), tantalum (Ta), molybdenum (Mo) and tungsten (W), even more preferably in the group consisting of vanadium ( V), molybdenum (Mo) and tungsten (W). In the case where the POM is based on vanadium, we can speak of polyoxovanadate. In the case where the POM is based on molybdenum, one can speak of polyoxomolybdate. In cases where the POM is based on tungsten, one can speak of polyoxotungstate. The POM used in the present invention may be a polyoxovanadate, a polyoxomolybdate, a polyoxotungstate, or mixtures thereof, and most particularly a polyoxotungstate. The polyoxotungstates are for example described in the reference work "Advanced Inorganic Chemistry: a comprehensive text" by Cotton and Wilkinson. The transition metal in the POM is generally in a high oxidation state, preferably V or VI.

According to one embodiment, the POM may consist solely of transition metal atoms and oxygen, which corresponds to the fact that the symbol r is zero in the general formula [X _r M _s O _t ] ^{p ~} . In this embodiment, the general formula of the POM is then [M _s O _t ] ^{p ~} , in which M, O, s, t and p have the meanings described above. This type of POM may be referred to as "isopolyanion".

However, it is possible in another embodiment that the POM also comprises one or more heteroatoms, which corresponds to the fact that the symbol r is different from zero in the general formula [X _r M _s O _t ] ^{p ~} . X is preferably selected from the group consisting of phosphorus (P) and silicon (Si). This type of POM may be referred to as "heteropolyanion".

The values of the symbols r, s, t and p are such that the valence rules of the different atoms are respected so as to obtain an anionic aggregate. The POM implemented in the present invention can be chosen from the group consisting of [Wi ₀ O ₃₂ ] ^{4 "} , [Mo ₆ O ₉ , [Vi ₀ O ₂₈ ] ^6" , [PWi ₂ O ₄ o] ^{3 ~} [ΡΜθι ₂ Ο ₄₀ , [SiWi ₀ O ₄₀ ] ^{4 "} and mixtures thereof Preferably, the POM used in the present invention is chosen from POMs containing no phosphorus. POM implemented in the present invention is [WIO0 ₃₂ ] ^{4 "} , commonly referred to as" decatungstate ".

POMs being ionic compounds, they can be in the form of salt. The counter-ion (s) may be chosen from the group consisting of the proton (H ⁺ ), the alkaline ions, in particular Na ⁺ , K ⁺ and Li ⁺ , by the halogenated cations, in particular iodonium, and by the cations. ammoniums, sulphoniums, phosphoniums, ferroceniums and carbocations. The photocatalyst used in step (a) of the method which is the subject of the invention may be a decatungstate salt. This is very preferably tetrabutylammonium decatungstate (TBADT), of formula (n-Bu ₄ N ⁺ ) ₄ [WIOO ₃₂ ] ^{4 "} .

POMs can be synthesized according to the methods described in the prior art. For example, the synthesis of TBADT has been described in the publication of Protti et al. {Chem. Commun., 2009, 7351-7353) and in the publication of Chemseddine et al. (Inorg Chem., 1984, 23, 2609). This synthesis can be carried out from sodium tungstate and tetrabutylammonium bromide in an acidic medium.

POMs in general, and decatungstate in particular, are advantageous because of their photochemical properties. They can indeed be excited under conditions of very gentle irradiation, near UV or visible light. This photocatalyst absorbs light in wavelengths between about 300 nm and about 420 nm. The maximum absorption in the acetonitrile of the decatungstate is centered on about 324 nm. The absorption of this compound in the visible is significant: the molar extinction coefficient at 400 nm (8400 _nm ) is about 400 L. mol ^"1 cm ^-1 and the molar extinction coefficient at 390 nm (8390 _nm) is about 500 L. mol ^"1 cm ^-1 . It is therefore possible to excite it in this range of wavelengths. The photocatalyst thus excited is then capable of producing an abstraction of hydrogen on a siloxane compound having a hydrogen atom bonded to a silicon atom.

The use of POM as photocatalyst for the hydrosilylation reaction of step (a) of the process according to the invention is particularly advantageous. The hydrosilylation reactions are conventionally carried out by catalysis, and the catalyst suitable for this reaction is typically a platinum catalyst, such as, for example, chloroplatinic acid hexahydrate or the Karstedt catalyst which is composed of platinum complexes with divinyltetramethyldisiloxane as ligand (see for example in US Patent 3,775,452). However, the use of platinum catalyst is problematic. It is indeed preferable to avoid the use of platinum on an industrial scale because it is an expensive metal, in the process of rarefaction and whose cost fluctuates enormously. The use of other catalysts has been proposed in the past, for example the use of rhodium or iridium. However, these metals are just as rare as platinum, and their use does not solve the problems mentioned.

In this context, the use of POM is an alternative to the platinum catalyzed hydrosilylation reaction. In the process according to the invention, step (a) uses a catalyst which is advantageously inexpensive, easily supplied, easy to handle and / or little or no toxic. In addition, the hydrosilylation yields obtained with this reciprocating catalyst are high.

In addition, the POM catalyst being active only when irradiated, it is easy to stop the hydrosilylation reaction by stopping the irradiation. This represents an advantage over catalysts used in the prior art with which it is difficult to control or stop the reaction when it has been initiated. One of the advantages of the present invention therefore lies in the fact that the unwinding of the reaction is controllable. The hydrosilylation reaction is thus safer from an industrial risk point of view. The hydrosilylation of step (a) is carried out between a chlorinated hydrogenosilane compound (A) and an unsaturated compound (B).

In the present invention, the chlorinated hydrogenosilane compound (A) has the general formula (I):

Z _a HCl _b Si (I)

a and b are integers, with 0, 1 or 2, b being 1, 2 or 3 and a + b = 3.

It is understood in formula (I) above that if several Z groups are present, they may be the same or different from each other.

Z can represent any monovalent radical different from a hydrogen atom and a chlorine atom, since it does not contain a reactive chemical function that can hinder or even prevent the hydrosilylation reaction. Preferably, Z is selected from the group consisting of an alkyl group having 1 to 8 carbon atoms, optionally substituted with at least one halogen atom, and an aryl group. More preferably, Z is selected from the group consisting of methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl. Even more preferentially, Z represents a methyl group.

In formula (I), the symbol a may preferably be 1 or 2. In a preferred embodiment, the chlorinated hydrogenosilane compound (A) is chosen from compounds of general formula (Ia), (Ib) or (Ie) :

CH ₃ HCl ₂ Si (la) (CH ₃ ) ₂ HClSi (Ib) HCl ₃ Si (le)

Step (a) of the process according to the invention may therefore consist of a step of hydrosilylation of a chlorinated hydrogenosilane compound (Aa) of general formula (Ia):

CH ₃ HCl ₂ Si (la), with an unsaturated compound (B) comprising at least one alkene function and / or an alkyne function, of general formula (II) or (III):

R R

\ /

C = C

to obtain a functionalized chlorinated silane compound (Ca) of general formula (IVa):

CH ₃ YCl ₂ Si (IVa),

in which Y is a functional group of general formula (V) or (VI): C-CH

I \ 4 1 2

R ^R (V) - CR = CHR (VI),

where R ¹ , R ² , R ³ and R ⁴ have the above meanings. Alternatively, step (a) of the process according to the invention may consist of a step of hydrosilylation of a chlorinated hydrogenosilane compound (Ab) of general formula (Ib):

(CH ₃ ) ₂ HClSi (Ib), with an unsaturated compound (B) comprising at least one alkene function and / or an alkyne function, of general formula (II) or (III):

R R

\ /

C = C

R ³ R ⁴ (II) R-C≡C-R ² (m) wherein R ¹ , R ² , R ³ and R ⁴ represent a monovalent radical;

to obtain a functionalized chlorinated silane compound (Cb) of general formula (IVb):

(CH ₃ ) ₂ YClSi (IVb),

in which Y is a functional group of general formula (V) or (VI): C-CH

R ^{3 Nr} (V) - CR = CHR ² (VI),

where R ¹ , R ² , R ³ and R ⁴ have the above meanings.

In the present invention, the unsaturated compound (B) comprising at least one alkene function and / or an alkyne function, has the general formula of general formula (II) or general formula (III): RR

\ /

C = C

R ³ R ⁴ (II) R- C≡C- R ² (m) wherein R ^1, R ^2, R ³ and R ⁴ represent a monovalent radical.

An "unsaturated compound" according to the invention is a chemical compound comprising at least one unsaturation not forming part of an aromatic ring. The unsaturated compound (B) comprises at least one alkene function and / or an alkyne function. Any compound comprising at least one alkene function and / or an alkyne function can be used in the process according to the invention, insofar as it does not contain a reactive chemical function which can hinder or even prevent the hydrosilylation reaction.

According to one embodiment, the unsaturated compound (B) comprises one or more alkene functional groups and from 2 to 40 carbon atoms. It may furthermore comprise 1 to 3 heteroatoms chosen from N, O, F, Cl, Br and I. When the unsaturated compound (B) comprises several alkene functional groups, these may be conjugated or unsubstituted.

According to another embodiment, the unsaturated compound (B) comprises one or more alkyne functions and from 2 to 40 carbon atoms. It may further comprise 1 to 3 heteroatoms chosen from N, O, F, Cl, Br and I. When the unsaturated compound (B) comprises several alkyne functions, these may or may not be conjugated.

The unsaturated compound (B) may also be chosen from compounds comprising several alkenes and / or alkynes, preferably two or three alkenes and / or alkynes. However, unsaturated compounds (B) comprising only one function selected from an alkene function and an alkyne function are preferred.

R ¹ , R ² , R ³ and R ⁴ may be chosen, independently of one another, from the group consisting of a hydrogen atom, a halogen atom chosen from fluorine, chlorine, bromine and bromine; iodine, alkyl, cycloalkyl, aryl, heteroaryl, heterocycloalkyl, alkoxy, aryloxy, cycloalkoxy, alkylsilyl, alkoxysilyl, carboxylic acid, esters alkyl group, a urea group, an amide group, a sulfonamide group, an imide group, a cyano group, an aldehyde group, an alcohol group, a thiol group, an amine group, an imine group, a sulfide group, a sulfoxide group, a sulfone group or an azide group; which groups may themselves be substituted on their (s) part (s) alkyl group (s) and / or cycloalkyl group (s) and / or aryl (s) by one or more alkyl groups to C _8, optionally halogenated, by one or more alkoxy groups -C _8, optionally halogenated by one or more aryl groups, optionally halogenated, with one or more cycloalkyl groups, optionally halogenated, by one or more heteroaryl groups, optionally halogenated, with one or more groups heterocycloalkyl, with one or more halogen atoms, with one or more carboxylic acid groups, with one or more ester groups, with one or more ether groups, with one or more urea groups, with one or more amide groups, with one or more or more than one sulfonamide group, one or more imide groups, one or more cyano groups, one or more aldehyde groups, one or more ketone functions, one or more alcohol groups by one or more thiol groups, one or more amino groups, one or more imine groups, one or more sulphide groups, one or more sulphoxide groups, one or more sulphone groups, and / or one or more azide groups; or

at least two groups chosen from R ¹ , R ² , R ³ and R ⁴ together with the carbon atoms to which they are bonded form one or more cycloalkyl, heterocycloalkyl, aryl or heteroaryl groups, these groups, cycloalkyl, heterocycloalkyl, aryl and heteroaryl groups; may be substituted by one or more alkyl groups to C _8, optionally halogenated with one or more alkoxy groups -C _8, optionally halogenated by one or more aryl, optionally halogenated with one or more atoms halogenated, with one or more carboxylic acid groups, with one or more ester groups, with one or more ether groups, with one or more urea groups, with one or more amide groups, with one or more sulphonamide groups, with one or more groups imides, by one or more cyano groups, by one or more aldehyde groups, by one or more ketone functions, by one or more alcohol groups, by one or more thiol groups, by one or more amino groups, by one or more imine groups, by one or more sulphide groups, by one or more sulphoxide groups, by one or more sulphone groups, and / or by one or more groups azides;

the remaining groups being as defined above.

By "alkyl" is meant according to the invention a saturated hydrocarbon chain, linear or branched containing from 1 to 20 carbon atoms, preferably from 1 to 8 carbon atoms. An alkyl group may be selected from the group consisting of methyl, ethyl, isopropyl, n-propyl, tert-butyl, isobutyl, n-butyl, n-pentyl, isoamyl and 1,1-dimethylpropyl.

By "cycloalkyl" is meant according to the invention a monocyclic or polycyclic saturated hydrocarbon group, preferably monocyclic or bicyclic, containing from 3 to 20 carbon atoms, preferably from 5 to 8 carbon atoms. When the cycloalkyl group is polycyclic, the multiple ring nuclei may be attached to each other by a covalent bond and / or by a spinan atom and / or be condensed to each other. Cycloalkyl may be selected from the group consisting of cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, adamantane and norborane.

By "aryl" is meant according to the invention an aromatic hydrocarbon group containing from 5 to 18 carbon atoms, monocyclic or polycyclic. An aryl group may be selected from the group consisting of phenyl, naphthyl, anthracenyl and phenanthryl.

By "halogen atom" is meant according to the invention an atom selected from the group consisting of fluorine, chlorine, bromine and iodine.

According to the invention, the term "heteroaryl" means an aryl group, that is to say an aromatic hydrocarbon group containing from 5 to 18 carbon atoms, monocyclic or polycyclic, in which at least one carbon atom has been substituted. by a heteroatom selected from O, N, S and P. A heteroaryl group may be selected from the group consisting of pyranyl, furanyl, pyridinyl, pyrimidinyl, pyrrolyl, pyrazolyl, imidazolyl, isothizolyl, isoxazolyl and indolyl.

According to the invention, the term "heterocycloalkyl" is intended to mean a cycloalkyl group, that is to say a monocyclic or polycyclic, preferably monocyclic or bicyclic, saturated hydrocarbon group containing from 3 to 20 carbon atoms, in which at least one The carbon atom has been substituted with a heteroatom selected from O, N, S and P. A heterocycloalkyl group may in particular be the oxiranyl monocyclic group or the epoxycyclohexyl bicyclic group.

By "alkoxy" is meant according to the invention an alkyl group as defined above bonded to an oxygen atom. An alkoxy group may be selected from the group consisting of methoxy, ethoxy, propoxy and butoxy. By "aryloxy" is meant according to the invention an aryl group as defined above bonded to an oxygen atom. An aryloxy group may be for example the phenoxy group.

By "cycloalkoxy" is meant according to the invention a cycloalkyl group as defined above bonded to an oxygen atom. By "alkylsilyl" is meant according to the invention an alkyl group as defined above bonded to a silicon atom.

By "alkoxysilyl" is meant according to the invention an alkoxy group as defined above bonded to a silicon atom.

Preferably, R ¹ , R ² , R ³ and R ⁴ represent, independently of one another:

a hydrogen atom;

alkyl to C _8, optionally substituted by hydroxy and / or by a halogen atom;

phenyl, optionally substituted with alkyl to C _4, by halogen, by alkyl to C ₄ itself substituted by one or more halogens, alkoxy C l -C ₄ or a amine function optionally substituted once or twice with alkyl to C _4; pyridine;

a C1 to Cs alkyl ester;

a cyano function;

a carboxylic acid function;

a C ₁ -C ₄ acyloxy group, in particular acetyloxy;

a primary amide group, in particular unsubstituted on nitrogen or substituted once or twice with a C1-C4 alkyl group _;

a polyethoxylated alkyl group, optionally substituted with a hydroxy or a ketone;

an epoxycyclohexyl group;

an oxiranyl group or a C1 to Cs alkyl group substituted with an oxiranyl group.

Advantageously, R ¹ may be a hydrogen atom, and R ² may represent a substituent other than a hydrogen atom. In the case of a compound of formula (II), R ³ and R ⁴ may furthermore be hydrogen atoms. Said unsaturated compound (B) may be chosen from the group consisting of:

acetylene;

acrylates and alkyl méthacrytales to C _4;

acrylic or methacrylic acid;

alkenes, preferably octene and more preferably 1-octene;

allyl alcohol;

allylamine;

allyl ether and glycidyl ether;

allyl ether and piperidine, preferably allyl ether and sterically hindered piperidine;

styrenes, preferably alpha-methylstyrene,

1,2-epoxy-4-vinylcyclohexane.

allyl chloride;

chlorinated alkenes, preferably allyl chloride; and

fluorinated alkenes, preferably 4,4,5,5,6,6,7,7,7-nonafluoro-1-heptene.

Very preferably, the unsaturated compound (B) is acetylene.

Embodiments wherein the unsaturated compound (B) comprises an alkyne function, and most particularly the embodiment where the unsaturated compound (B) is acetylene, are preferred in the process according to the present invention as they allow the preparation of polyorganosiloxanes comprising at least one functional group having an alkene-type unsaturation, and especially vinyl groups.

One of the problems conventionally encountered in the processes of the prior art comprising a step of hydrosilylation of unsaturated compounds comprising an alkyne function is the presence of a parasitic hydrosilylation secondary reaction. Indeed, the product obtained after the main hydrosilylation reaction itself has an alkene function and it can react a second time with a chlorinated hydrogenosilane compound (A) by hydrosilylation. The by-product obtained is undesired and it is desired to minimize its formation.

Without wishing to be bound by this theory, however, the Applicant believes that this parasitic secondary reaction is favored by a long reaction time. The use of a photocatalyst of the POM type, as in step (a) of the process according to the present invention, advantageously makes it possible to better control the duration of the reaction. hydrosilylation. It can thus also make it possible to solve, at least partially, this secondary reaction problem of the prior art.

From an implementation point of view, step (a) of the process according to the invention comprises a step of bringing the unsaturated compound (B) into contact with the chlorinated hydrogenosilane compound (A) in the presence of the catalyst. The bringing into contact of these three elements can be made according to conventional techniques known to those skilled in the art.

Step (a) of the process according to the invention can be carried out in a solvent. Suitable solvents are those miscible with the unsaturated compound (B) and with the chlorosilane compound (A). Examples of particular solvents are the aliphatic hydrocarbons, for example pentane, hexane, heptane, pentamethylheptane and petroleum distillation fractions, aromatic hydrocarbons, for example benzene, toluene and ortho para- or meta-xylene, halogenated aliphatic or aromatic hydrocarbons, for example tetracholoethylene, and ethers, for example tetrahydrofuran and dioxane. Alternatively, in the case where the unsaturated compound (B) or the chlorinated hydrogenosilane compound (A) is in liquid form at the temperature of the hydrosilylation reaction, it may be envisaged to use this compound as a solvent for the reaction. The reaction medium can then advantageously be without solvent.

The unsaturated compound (B), the chlorinated hydrogenosilane compound (A) and the catalyst can be contacted in the same phase, thus forming a homogeneous reaction medium, or else be in different phases.

According to a first embodiment, the hydrosilylation step (a) according to the invention is carried out in homogeneous solution. The reagents, i.e., the unsaturated compound (B) and the chlorinated hydrogen silane compound (A), and the photocatalyst can be dissolved in a solvent suitably selected to solubilize all compounds. This solvent is preferably an organic solvent or a mixture of several organic solvents. This solvent may be selected from the group consisting of acetonitrile, dichloroethane, nitromethane, 2-methyl-tetrahydrofuran, dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone and mixtures thereof. The solvent is preferably selected from acetonitrile and mixtures of acetonitrile and other one or more other organic co-solvent (s). The organic co-solvent (s) may be chosen from toluene, dichloromethane and tetrahydrofuran. When one or more co-solvent (s) is (are) used in admixture with acetonitrile, the ratio The volume of the co-solvent (s) relative to the acetonitrile is preferably between 1: 10 and 6: 1, and more preferably between 3: 1 and 4: 1. The use of the Acetonitrile alone as a solvent for the reaction has the advantage of obtaining a perfectly homogeneous reaction medium. However, since acetonitrile has a high cost, the use of a co-solvent with acetonitrile can also be considered advantageous because it makes it possible to reduce the volume of acetonitrile required, and thus to reduce costs.

According to a second embodiment, step (a) of hydrosilylation is carried out by heterogeneous catalysis. In this embodiment, the reagents, i.e. the unsaturated compound (B) and the chlorinated hydrogenosilane compound (A), can be dissolved in a solvent suitably selected to solubilize these reagents, but not the photocatalyst. This can remain in solid form. Heterogeneous catalysis is particularly advantageous because it allows easy separation of the catalyst with the reagents and products of the reaction, and easy recycling of the catalyst. The solvent of the reaction phase is preferably an organic solvent or a mixture of several organic solvents. The solvent is preferably toluene.

In this second embodiment of step (a) of hydrosilylation by heterogeneous catalysis, the photo-catalyst according to the invention may optionally be introduced into a solid dispersing medium. Different techniques are known to those skilled in the art. For example, the photocatalyst may be impregnated on a solid support, immobilized in a silica network, fixed on a previously functionalized silica, fixed on an ion exchange resin or fixed in a polymer membrane. Some embodiments are for example described in the publication by D. Tzirakis et al. "Decatungstate as efficient photocatalysts in organic chemistry" (Chemical Society Reviews, 2009, 38, 2609-2621). Whether the reaction is carried out in homogeneous or heterogeneous catalysis, the catalyst according to the invention is introduced into the reaction medium at a concentration of preferably between 0.01% and 50%, more preferably between 0.05% and 5%, and even more preferably between 1% and 2%, the catalyst concentration being expressed as mole percent of catalyst relative to the reactant in the hydrosilylation reaction which may be the hydrogenosilane reactant (A) or the unsaturated reagent (B).

According to the reaction equations (1) and (2) above, the stoichiometric ratio of the hydrosilylation reaction is 1 mole of hydrogenosilane compound per 1 mole of unsaturated compound. However, this stoichiometric ratio may vary in cases where the hydrogenosilane compound (A) and / or the unsaturated compound (B) comprise more than one reactive function. In the process according to the invention, the molar ratio of the Si-H functions of the hydrogenosilane compounds (A) to the alkenes and alkynes functions of the unsaturated compounds (B) is preferably between 0.01: 1 and 10: 1 and more preferably between 0.1: 1 and 1: 1. Advantageously, the Si-H functions of the hydrogenosilane compounds (A) may be in fault with respect to the alkenes and alkynes functions of the unsaturated compounds (B).

In addition, the reaction medium may optionally be degassed, so as to be free of oxygen. The optional degassing step can improve the kinetics of the reaction, particularly in cases where the reagents are air-sensitive compounds.

To promote the hydrosilylation reaction, the photocatalyst according to the invention must be excited using a light source. The method according to the invention preferably comprises at least one step of irradiating the photocatalyst with UV or visible light. This irradiation can be carried out using any existing device, delivering light at the desired wavelength. It may be conventionally an incandescent lamp, an LED lamp, a discharge lamp, including mercury discharge and xenon, or a fluorescent lamp. It can also be a laser source. The irradiation is preferably carried out at a wavelength between 300 nm and 500 nm, more preferably between 300 nm and 420 nm, and even more preferably between 350 nm and 400 nm. The irradiation energy is preferably between 1 mW / cm ² and 5 W / cm ² , more preferably between 1 mW / cm ² and 200 mW / cm ² , and even more preferably between 10 mW / cm ² and 100 mW / cm ² .

According to one embodiment, the irradiation can be kept constant throughout the duration of the hydrosilylation reaction. According to an alternative embodiment, the irradiation can be modified or interrupted during the hydrosilylation reaction. According to another alternative embodiment, the irradiation can be minced, which means that the irradiation follows a start / stop cycle at a constant or variable frequency.

The hydrosilylation process can be carried out at a temperature between 0 ° C and 150 ° C, preferably between 10 ° C and 30 ° C, and more preferably at room temperature. For the measurement of the temperature of the hydrosilylation reaction in the present invention, the heating which may possibly be produced by the present invention is not taken into account. source of irradiation. This process is advantageously carried out at atmospheric pressure, but it is conceivable to carry out this process under-pressure, for example between 0.01 MPa (100 mbar) and 0.08 MPa (800 mbar), or in overpressure for example between 0.1 MPa (1 bar) and 8 MPa (80 bar). The hydrosilylation step (a) according to the invention may be a batch process, commonly called batch type according to the English terminology. The reaction may be conducted for a period of time which varies depending on the reagents involved, the catalyst used and the reaction conditions, in particular depending on the concentrations of reactants and catalyst. In general, the reaction time may be between 1 minute and 24 hours, preferably between 30 minutes and 8 hours, and even more preferably between 1 hour and 4 hours.

However, it is also envisaged to implement step (a) of the method according to the invention continuously. According to this embodiment, the reactants are introduced into the reactor in the form of one or more continuous streams. The photocatalyst can, for its part, also flow continuously in the reactor, particularly if the process is carried out in a homogeneous solution. In the case of heterogeneous catalysis, it may be fixed inside the reactor, for example in the form of a fixed catalytic bed or a mobile catalytic bed. When the process according to the invention is a continuous process, the flow rate of the flows flowing in the reactor can be fixed by those skilled in the art depending on the volume of the reactor so as to ensure a residence time of the sufficient reagents, in the presence of photocatalyst, so that the hydrosilylation reaction is carried out.

The inventors have discovered that, advantageously, the use of the photocatalyst according to the invention makes it possible to carry out hydrosilylation reactions under operating conditions that are easy to implement, without particularly dangerous or expensive compounds, with conversion rates. quite interesting. The conversion rates of hydrogenosilane reagent (A) can advantageously be greater than 50%, even 60%, even 75%, even 80%, even 90%, and preferably between 90 and 100%.

In the present application, the terms "conversion rate" and "conversion rate", abbreviated TT, are synonymous and denote, for each reagent, in percent, the initial number of moles of Si-H functions of the hydrogenosilane reagent (A). ) or alkenes and alkynes of the unsaturated reactant (B), minus the number of moles of these remaining functions after reaction, divided by the initial number of moles of these functions. At the end of step (a) of the process according to the invention, a functionalized chlorinated silane compound (C) of general formula (IV) is obtained:

ZaClbYSi (IV)

in which - Z, a and b are the same as those of the general formula (I)

Y is a functional group of general formula (V) or (VI): C-CH

I Q \ 4 1 2

R ^R (V) - CR = CHR (VI),

where R ¹ , R ² , R ³ and R ⁴ have the above meanings.

According to a preferred embodiment, in the general formula (IV), Y may represent a linear or branched radical containing between 2 and 12 carbon atoms, having at least one alkene function, and optionally at least one heteroatom. Said alkene function may advantageously be located at the end of the chain. Y may advantageously represent a radical chosen from the group consisting of vinyl, propenyl, 3-butenyl, 5-hexenyl, 9-decenyl, 10-undecenyl, 5,9-decadienyl and 6,11-dodecadienyl. Very preferably, Y may represent a vinyl radical. The compound (C) may be a compound of general formula (IVa): CH ₃ YCl ₂ If (IVa) wherein Z has its previous significance. In particular, the functionalized chlorinated silane compound (C) obtained at the end of step (a) may be dichloromethylvinylsilane of formula (CH ₃ ) (CH ₂ = CH) Cl ₂ Si.

Compound (C) may also be a compound of general formula (IVb): (CH ₃ ) ₂ YClSi (IVb), wherein Z has the above meaning. In particular, the functionalized chlorinated silane compound (C) obtained at the end of step (a) may be chlorodimethylvinylsilane of formula (CH ₃ ) ₂ (CH ₂ = CH) ClSi.

The method according to the invention may also comprise an intermediate step, between step (a) and step (b), of separation and optionally purification of the products obtained at the end of step (a). Separation and purification means are well known to those skilled in the art. In particular, this intermediate step may comprise a distillation. Step (b) of the process according to the invention is a hydrolysis and condensation step of a composition comprising at least one functionalized chlorinated silane compound (C) of general formula (IV) which has been obtained at the end of from step (a), and which has optionally been separated and purified. The composition used during step (b) may therefore comprise one or more functionalized chlorinated silane compounds (C), which may be alone or in mixture with other chlorinated silane or other compounds.

According to a preferred embodiment, the composition undergoing step (b) of hydrolysis and condensation comprises only one functionalized chlorinated silane compound (C). Thus, the composition undergoing step (b) of hydrolysis and condensation may consist of a functionalized chlorinated silane compound (Ca) of general formula (IVa): CH ₃ YCl ₂ Si (IVa), in which Z has the meaning above, and in particular it may consist of dichloromethylvinylsilane of formula (CH 3) (CH ₂ = CH) Cl ₂ Si. Alternatively, the composition undergoing step (b) of hydrolysis and condensation may consist of a functionalized chlorinated silane compound (Cb) of general formula (IVb): (CH ₃ ) ₂ YClSi (IVb), wherein Z has the above meaning, and in particular it may consist of chlorodimethylvinylsilane of formula (CH ₃ ) ₂ (CH ₂ = CH) ClSi .

Hydrolysis and condensation of organohalosilane compounds are well known to those skilled in the art. Many documents in the literature describe ways of implementing this step. Those skilled in the art can for example refer to patent documents EP 0 590 773, US 5 395 956, EP 0 876 419, EP 00 998 519 and EP 1 809 688. Typically, during step (b) d hydrolysis and condensation, the composition comprising at least one functionalized chlorinated silane compound (C) is brought into contact with water in a continuous reactor. The mixture is hydrolysed, the hydrolysates condense together and hydrochloric acid is separated in a decanter. The product is washed to remove the residual acid, possibly neutralized, dried and filtered.

At the end of step (b) of hydrolysis and condensation of the process according to the invention, at least one linear or cyclic oligomer (D) comprising at least two units of formula (VII) is obtained:

Z _to YSiO _((3- _a) / ₂₎ (VII)

in which - Z and a are the same as in general formula (I)

- Y is the same as in the general formula (IV). In the present invention, the term "oligomer" means polymeric compounds whose unit unit number is at least 2 and not more than about 10.

The oligomer (D) may be a cyclic siloxane (Da) of general formula (VIIa) or a linear siloxane (Db) of general formula (VIIIb):

(Vlla) (Vllb) in which - Z and Y have the above meanings, and

n and m are independently integers from 3 to 9.

These parent (Da) and (Db) oligomers can in particular be obtained when the composition undergoing step (b) of hydrolysis and condensation consists of a functionalized chlorinated silane compound (Ca) of general formula (IVa): CH ₃ YCl ₂ If (IVa).

Very preferably, the oligomer (D) can be:

a cyclic polymethylvinylsiloxane comprising from 3 to 9 silicon atoms; a linear polymethylvinylsiloxane comprising from 3 to 9 silicon atoms, and a mixture thereof.

The oligomer (D) may also be a disiloxane (De) of general formula (VIIc)

wherein Z and Y have the above meanings.

These disiloxanes (De) can in particular be obtained when the composition undergoing step (b) of hydrolysis and condensation consists of a functionalized chlorinated silane compound (Cb) of general formula (IVb): (CH ₃ ) ₂ YClSi (IVb) ). Very preferably, the oligomer (De) may be divinyltetramethylsiloxanes:

Disiloxanes (De) are particularly useful in polymerization reactions such as step (c) of the process according to the invention as a chain limiter.

If the product obtained at the end of step (b) is not pure, it is possible to proceed to a second optional step of separation and purification. The method according to the invention may also comprise an intermediate step, between step (b) and step (c), of separation and optionally purification of the products obtained at the end of step (b). Separation and purification means are well known to those skilled in the art. In particular, this intermediate step may comprise a distillation.

The oligomers (D) obtained at the end of step (b) of the process according to the invention may advantageously be used during step (c) as reagents for the preparation of the desired functionalized polyorganosiloxanes (E). The composition implemented during step (c) may therefore comprise one or more oligomers (D), which may be alone or in mixture with other chlorinated silane or other compounds. According to a preferred embodiment, the composition undergoing the polymerization step (c) comprises at least one cyclic siloxane (Da) of general formula (Vlla), a linear siloxane (Db) of general formula (Vllb), or a mixture of these:

in which - Z and Y have the above meanings, and

n and m are independently integers from 3 to 9.

These cyclic (Da) and / or linear (Db) siloxanes may be alone or in mixtures, in the composition implemented in step (c), with other cyclic or linear siloxanes.

According to a first embodiment, the composition undergoing step (c) may comprise only cyclic (Da) and / or linear (Db) siloxanes in which all Ys have the same meaning. In particular, the composition undergoing step (c) may consist solely of cyclic polymethylvinylsiloxanes comprising from 3 to 9 atoms of silicon, linear polymethylvinylsiloxanes comprising from 3 to 9 silicon atoms, and a mixture thereof.

According to a second embodiment, the composition undergoing step (c) may comprise cyclic (Da) and / or linear (Db) siloxanes mixed with cyclic or linear siloxanes different from (Da) and (Db), in particular in mixture with:

cyclic polydimethylsiloxanes comprising from 3 to 9 silicon atoms, linear polydimethylsiloxanes comprising from 3 to 9 silicon atoms, cyclic polymethylhydrogenosiloxanes comprising from 3 to 9 silicon atoms,

linear polymethylhydrogenosiloxanes comprising from 3 to 9 silicon atoms,

and mixtures thereof.

In this first and in this second embodiment, it is also envisaged that the composition undergoing step (c) comprises chain-limiting siloxane compounds, in particular disiloxanes, for example hexamethyldisiloxanes and / or tetramethyldivyl idisil xanes. .

In a third embodiment, the composition undergoing step (c) may consist of polydimethylsiloxanes chosen from cyclic polydimethylsiloxanes comprising from 3 to 9 silicon atoms, linear polydimethylsiloxanes comprising from 3 to 9 silicon atoms, and mixtures of these, and at least one disiloxane (De) of the general formula (VIIc)

Z Z

I I

Y Si- O- Si- Y

I I

z Z (vile)

wherein Z and Y have the above meanings.

The disiloxane (De) may in particular be a tetramethyldivinyldisiloxane. Polymerization reactions are well known to those skilled in the art. Many documents in the literature describe ways of implementing this step. Those skilled in the art can for example refer to patent documents FR 2,353,589 and EP 1,856,191. This step (c) consists in polymerizing and rearranging low molecular weight oligomers to convert them into polymers of higher molecular weight. high. For this step, basic catalysts such as alkali metal hydroxides, alkali metal siloxanes and alkoxides, or quaternary ammonium hydroxides may be used.

The polymerization step (c) makes it possible to obtain a composition comprising a polyorganosiloxane (E) comprising at least said unit (VII):

Z _to YSiO (( _3-a ) / 2) (VII)

in which - Z and a are the same as in the general formula (I), and

- Y is the same as in the general formula (IV).

Depending on the reagents and the parameters chosen for carrying out the polymerization reaction, it is possible to obtain polyorganosiloxanes (E) of any type.

According to a preferred embodiment:

Y represents a linear or branched radical containing between 2 and 12 carbon atoms, having at least one alkene function, and optionally at least one heteroatom, and

Z represents a monovalent radical not comprising an alkene or alkyne function.

In addition, the polyorganosiloxane (E) may optionally comprise other units of formula (VIII):

in which :

Z has the same meaning as above, and

i represents an integer between 0 and 3.

It is understood that if several Y and Z groups are present in the same pattern, they may be the same or different from each other. In addition, in formula (VII) and in formula (VIII), Z may represent a monovalent radical selected from the group consisting of an alkyl group having 1 to 8 carbon atoms, optionally substituted by at least one halogen atom. , and an aryl group. Z may advantageously represent a monovalent radical selected from the group consisting of methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl. In addition, in formula (VII), Y may have an alkene function advantageously at the chain end. Y may advantageously represent a radical chosen from the group consisting of vinyl, propenyl, 3-butenyl, 5-hexenyl, 9-decenyl, 10-undecenyl, 5,9-decadienyl and 6,11-dodecadienyl. The polyorganosiloxane (E) may have a linear, branched, cyclic or lattice structure.

In the case of linear polyorganosiloxanes, these can essentially consist of:

- Siloxyl units "D" selected from the units of formulas YZS1O2 / 2 and Z2S1O2 / 2;

- Siloxyl "M" units selected from the units of formulas YZ2S1O1 / 2 and Z3S1O2 / 2.

By way of examples of "D" units, mention may be made of dimethylsiloxy, methylphenylsiloxy, methylvinylsiloxy, methylbutenylsiloxy, methylhexenylsiloxy, methyldecenylsiloxy and methyldecadienylsiloxy groups.

By way of example of "M" units, mention may be made of trimethylsiloxy, dimethylphenylsiloxy, dimethylvinylsiloxy and dimethylhexenylsiloxy groups.

These linear polyorganosiloxanes may be oils having a dynamic viscosity at 25 ° C. of between 1 mPa.s and 100,000 mPa.s, preferably between 10 mPa.s and 5,000 mPa.s, or gums having a dynamic viscosity at 25.degree. ° C greater than 100 000 mPa.s. In the case of cyclic polyorganosiloxanes, these may consist of "D" siloxyl units chosen from the units of formulas Y 2 SiO 2/2, Y 2 SiO 2/2 and Z 2 SiO 2/2. Examples of such "D" patterns are described above. These cyclic polyorganosiloxanes can have a dynamic viscosity at 25 ° C of between 1 mPa.s and 5000 mPa.s. The dynamic viscosity at 25 ° C. of all the polymers described in the present application can be measured using a Brookfield viscometer, according to the AFNOR NFT 76 102 standard of February 1972.

Examples of polyorganosiloxanes (E) obtainable by the process which is the subject of the present invention are:

dimethylvinylsilyl dimethylpolysiloxanes; dimethylphenylmethylpolysiloxanes with dimethylvinylsilyl ends;

dimethylvinylmethylpolysiloxanes with dimethylvinylsilyl ends;

dimethylvinylmethylpolysiloxanes with trimethylsilyl ends;

cyclic methylvinylpolysiloxanes.

EXAMPLES

Synthesis of tetrabutylammonium decatungstate (TBADT)

Tetrabutylammonium bromide (10.7 g) and sodium tungstate dihydrate (22.2 g) were dissolved separately in 600 ml of water in two Erlenmeyer flasks and heated to 90 ° C with vigorous stirring. The pH of each solution was adjusted to 2, in a controlled manner, by dropwise addition of concentrated hydrochloric acid (the sodium tungstate solution then takes on a slight green color). Both solutions were then mixed and maintained at 90 ° C for 1 hour 30 minutes. A white slurry of TBADT was formed, and allowed to cool to room temperature and then filtered through sintered glass (porosity # 4). The solid was washed with water and dried in an oven at 110 ° C overnight. After cooling to room temperature, the white solid was ground with mortar to yield TBADT (20.3 g, 91%) as a fine white powder. The purity was evaluated more than 80% by UV spectrometry (ε ₃₂₃ = 1.35 × 10 ⁴ dm ³ · mol ^-1 cm ^-1 in acetonitrile).

The absorption spectrum of synthesized TBADT was obtained in acetonitrile using the JASCO V530 UV-Visible Spectrometer. The absorption spectrum is reproduced in FIG.

Hydrosilylation of ethyl acrylate with a siloxane In a flask equipped with a magnetic bar, an argon or nitrogen inlet and a septum, were successively introduced TBADT (10 mol%>) 1,1,1,3,5,5,5-heptamethyltrisiloxane (1.5 equiv) of formula (VIII):

degassed dry acetonitrile (by three successive cycles of freezing / vacuum / melting) and ethyl acrylate (1 equiv).

The reaction medium was irradiated with a UV lamp (Omnicure 1000 series) emitting in the UV at 365 nm, at an energy equal to 20% of the maximum energy of the lamp of 270 mW / cm ^{2 for} 3 hours. After the reaction was complete, the solvents were evaporated under reduced pressure. The proton NMR of the crude reaction product makes it possible to estimate the conversion rate. The reaction crude was then purified by flash chromatography on silica gel. The conversion rate and the relative yield of the reaction were measured by 1 H 300 MHz NMR analysis.

The compound of formula (XI):

was obtained with a conversion rate of 84% and a yield of 10%>.

The yield refers here, in percent, the number of moles of product (IX) obtained after reaction divided by the initial number of moles of ethyl acrylate.

Claims

A process for the preparation of a functionalized polyorganosiloxane comprising the following steps: a) a step of hydrosilylation of a chlorinated hydrogenosilane compound (A) of general formula (I):

Z _a HCl _b Si (I)

a and b are integers, with 0, 1 or 2, b being 1, 2 or 3 and a + b = 3;

R R

\ /

C = C

Z _a Cl _b YSi (IV)

in which - Z, a and b are the same as those of the general formula (I)

Y is a functional group of general formula (V) or (VI): C-CH

I Q \ 4 1 2

R ^R (V) - CR = CHR (VI),

where R ¹ , R ² , R ³ and R ⁴ have the above meanings; b) a step of hydrolyzing and condensing a composition comprising at least one functionalized chlorinated silane compound (C) of general formula (IV) obtained at the end of step (a) to obtain at least one oligomer ( D) linear or cyclic comprising at least two units of formula (VII):

Z _to YSiO (( _3-a ) / 2) (VII) in which - Z and a are the same as in general formula (I), - Y is the same as in general formula (IV); and c) a step of polymerizing a composition comprising at least one oligomer (D) obtained at the end of step (b) so as to obtain a composition comprising a polyorganosiloxane (E) comprising at least said unit (VII ).

2. Process according to claim 1, characterized in that Z is chosen from the group consisting of an alkyl group having 1 to 8 carbon atoms, optionally substituted with at least one halogen atom, and an aryl group, preferably in the group consisting of methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl, and more preferably Z represents a methyl group.

3. Process according to either of Claims 1 and 2, characterized in that the chlorinated hydrogenosilane compound (A) is chosen from compounds of general formula (Ia), (Ib) or (Ic):

CH ₃ HCl ₂ Si (la) (CH ₃ ) ₂ HClSi (Ib) HCl ₃ Si (le).

4. Method according to any one of claims 1 to 3, characterized in that the unsaturated compound (B) comprises from 2 to 40 carbon atoms and one or more functions alkene and / or alkynes.

5. Method according to any one of claims 1 to 4, characterized in that R ¹ is a hydrogen atom, R ² represents a substituent different from a hydrogen atom, and in the case of a compound of formula (II), R ³ and R ⁴ are hydrogen atoms.

6. Process according to any one of claims 1 to 5, characterized in that the unsaturated compound (B) is acetylene.

7. Method according to any one of claims 1 to 6, characterized in that it comprises an intermediate step of separation and optionally purification of the products obtained at the end of step (a).

8. Method according to any one of claims 1 to 7, characterized in that the linear polyorganosiloxanes (E) are oils having a dynamic viscosity at 25 ° C between 1 mPa.s and 100 000 mPa.s, preferably between 10 mPa.s and 5,000 mPa.s, or gums having a dynamic viscosity at 25 ° C greater than 100,000 mPa.s.

9. Process according to any one of claims 1 to 9, characterized in that the polyorganosiloxane (E) obtained at the end of step (c) is chosen from the group consisting of:

dimethylvinylsilyl dimethylpolysiloxanes;

dimethylphenylmethylpolysiloxanes with dimethylvinylsilyl ends;

dimethylvinylmethylpolysiloxanes with dimethylvinylsilyl ends;

dimethylvinylmethylpolysiloxanes with trimethylsilyl ends;

cyclic methylvinylpolysiloxanes.

10. Method according to any one of claims 1 to 9, characterized in that said photocatalyst of step (a) is a decatungstate.