Manganese complex photocatalyzed hydrosilylation process

Abstract

The present invention relates to hydrosilylation reactions between a monosubstituted alkene compound and a compound comprising at least one hydrogen atom bonded to a silicon atom. More specifically, the invention relates to a process for the hydrosilylation of an unsaturated compound (A) comprising at least one monosubstituted alkene function, with a compound (B) comprising at least one hydrogenosilyl function, said process comprising the step of subjecting said unsaturated compound (A) and said compound (B) to irradiation in the presence of a photocatalyst (C) consisting of a manganese carbonyl. This hydrosilylation reaction between an alkene compound and a compound comprising at least one hydrogen atom bonded to a silicon atom allows in particular the curing by crosslinking of silicone compositions. No figures

Description

Title of the invention: Photocatalyzed hydrosilylation process using a manganese complex Technical field

[0001] The present invention relates to hydrosilylation reactions between a monosubstituted alkene compound and a compound comprising at least one hydrogen atom bonded to a silicon atom. More specifically, the invention relates to a hydrosilylation process photocatalyzed by a manganese complex. This hydrosilylation reaction between an alkene compound and a compound comprising at least one hydrogen atom bonded to a silicon atom allows in particular the curing by crosslinking of silicone compositions. State of the prior art

[0002] During a hydrosilylation reaction of alkene compounds (also called poly-addition), a compound comprising at least one double bond reacts with a compound comprising at least one hydrogenosilyl function, i.e. a hydrogen atom linked to a silicon atom. This reaction can for example be described by :

[0004] The hydrosilylation reaction may be accompanied by, or sometimes even replaced by, a dehydrogenative silylation reaction (also called dehydrosilylation). The reaction may be described by:

[0005] H zi / f JG— ----------*• —-âi-—C-—C

[0006] The hydrosilylation reaction is notably used to crosslink silicone compositions comprising organopolysiloxanes carrying alkenyl units and organopolysiloxanes comprising hydrogenosilyl functions.

[0007] The hydrosilylation reaction of alkene compounds is typically carried out by catalysis, using metallic or organometallic catalysts. Currently, the suitable catalyst for this reaction is a platinum catalyst. Thus, most industrial hydrosilylation processes, in particular of alkenes, are catalyzed by Speier hexachloroplatinic acid or by the Karstedt Pt(O) complex of general formula Pt2(divinyltetramethyldisiloxane)3 (or abbreviated Pt2(DVTMS)3).

[0008] In the early 2000s, the preparation of platinum-carbene complexes allowed to have access to more stable catalysts (see for example patent application WO 01 / 42258).

[0009] However, the use of platinum metal or organometallic catalysts is still problematic. It is an expensive and becoming scarce metal and its cost fluctuates enormously. Its use on an industrial scale is therefore difficult. We therefore want to reduce as much as possible the quantity of catalyst required for the reaction, without reducing the yield and speed of the reaction. Many studies have been carried out to find alternatives to the Karstedt catalyst.

[0010] In 1966, in US patent US 3,271,362, the problem of replacing chloroplatinic acid as a hydrosilylation catalyst was already raised. The inventors of this patent proposed the use of a carbonyl metal catalyst chosen from the group consisting of cobalt cyclopentadienyl dicarbonyl [C5H5 Co(CO)2], dimanganese decacarbonyl [Mn2(CO)i0] and dicobalt octacarbonyl [Co2(CO)8]. In the only embodiment using dimanganese decacarbonyl, the reaction is carried out at 125°C and no precise indication is given on the yield of the reaction and the nature of the polyaddition products.

[0011] In 2021, Dong et al. described in a scientific publication (“Manganese-catalyzed divergent silylation of alkenes”, Nature Chemistry volume 13, pages 182-190 (2021)) a manganese-based catalyst for the dehydrosilylation and hydrosilylation of alkenes. Mn2(CO)i0 is used as a metal precursor and must be associated with a ligand, preferably a JackiePhos ligand to promote the hydrosilylation reaction. The reaction is carried out at 120°C.

[0012] Dimanganese decacarbonyl has also been described as a catalyst in other reactions. For example, the scientific publication by Liang et al (“Visible-Light-Initiated Manganese-Catalyzed E-Selective Hydrosilylation and Hy-drogermylation of Alkyne”, Org. Lett. 2019, 21, 8, 2750-2754) describes the use of 10 mol.% Mn2(CO)i0 as a photocatalyst for the hydrosilylation reaction of alkynes. Unlike alkenes, alkynes cannot undergo dehydrosilylation.

[0013] It is in this context that the inventors sought a more efficient process for the hydrosilylation of alkene compounds. Advantageously, it is desired that the reaction be rapid and at moderate temperature, preferably at room temperature. In addition, it is desired that the hydrosilylation reaction be selective, that the dehydrosilylation and / or isomerization reactions of the alkene compound be reduced or even negligible. Finally, it is desired that the catalyst contain an abundant, inexpensive and non-toxic chemical element. Summary of the invention

[0014] Unexpectedly, the inventors discovered that the hydrosilylation reaction of monosubstituted alkenes could be photocatalyzed under mild conditions by manganese carbonyl complexes, with excellent yields and excellent selectivity. In particular, this photocatalyzed reaction produces little or no dehydrosilylation and / or isomerization products of the monosubstituted alkene compound.

[0015] The subject of the present invention is a process for the hydrosilylation of an unsaturated compound (A) comprising at least one monosubstituted alkene function, with a compound (B) comprising at least one hydrogenosilyl function, said process comprising the step of subjecting said unsaturated compound (A) and said compound (B) to irradiation in the presence of a photocatalyst (C) consisting of a manganese carbonyl.

[0016] The present invention also relates to the use of a manganese carbonyl as a photocatalyst for a hydrosilylation reaction of an unsaturated compound (A) comprising at least one monosubstituted alkene function, with a compound (B) comprising at least one hydrogenosilyl function. Detailed description of the invention

[0017] Unless otherwise indicated, all the viscosities of the silicone oils referred to in this document correspond to a dynamic viscosity quantity at 25°C known as “Newtonian”, i.e. the dynamic viscosity which is measured, in a manner known per se, with a Brookfield viscometer at a shear rate gradient sufficiently low so that the measured viscosity is independent of the rate gradient.

[0018] Although not drawn, possible tautomeric forms of the compounds described herein are included within the scope of the present invention.

[0019] In the present invention, an alkyl group may be linear or branched. An alkyl group preferably comprises between 1 and 30 carbon atoms, more preferably between 1 and 12 carbon atoms, even more preferably between 1 and 6 carbon atoms. An alkyl group may for example be chosen from the following groups: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl and n-dodecyl.

[0020] In the present invention, a cycloalkyl group may be monocyclic or polycyclic, preferably monocyclic or bicyclic. A cycloalkyl group preferably comprises between 3 and 30 carbon atoms, more preferably between 3 and 8 carbon atoms. A cycloalkyl group may for example be chosen from the following groups: cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, adamantane and norborane.

[0021] In the present invention, an aryl group may be monocyclic or polycyclic, preferably monocyclic, and preferably comprises between 6 and 30 carbon atoms, more preferably between 6 and 18 carbon atoms. An aryl group may be unsubstituted or be substituted one or more times by an alkyl group. The aryl group may be selected from phenyl, naphthyl, anthracenyl, phenanthryl, mesityl, tolyl, xylyl, diisopropylphenyl and triisopropylphenyl groups.

[0022] In the present invention, an aryl-alkyl group preferably comprises between 6 and 30 carbon atoms, more preferably between 7 and 20 carbon atoms. An aryl-alkyl group may for example be chosen from the following groups: benzyl, phenylethyl, phenylpropyl, naphylmethyl, naphthylethyl and naphthylpropyl.

[0023] In the present invention, the halogen atom may for example be selected from the group consisting of fluorine, bromine, chlorine and iodine, with fluorine being preferred. A fluorine-substituted alkyl group may for example be trifluoropropyl.

[0024] The present invention uses a photocatalyst (C) consisting of a manganese carbonyl. Advantageously, manganese is an abundant natural element and generally considered non-toxic within the limits of the doses which make it a trace element. In the present invention, the manganese carbonyl is a metal complex consisting of one or more manganese atoms and carbonyl ligands linked to the manganese. No other type of ligand is linked to the manganese. Preferably, the manganese carbonyl is more specifically di-manganese decacarbonyl, of chemical formula [Mn2(CO)i0]. Advantageously, it is a commercial product, inexpensive and stable in air.

[0025] The photocatalyst (C) according to the invention is advantageously implemented without organic ligand, in particular: - without a nitrogen-based ligand, such as for example a pyridine ligand, and / or - without a phosphorus-based ligand, such as for example a phosphine ligand, and / or - without acyl ligand, and / or - without a diketone ligand, such as for example a [3-diketone] ligand, and / or - without a cyclopentadienyl ligand, substituted or unsubstituted, and / or - without an organometallic ligand, such as triphenylarsine.

[0026] The manganese in the metal complex is preferably in oxidation state 0. Said metal complex does not contain any X-type ligand, in particular any halogen ligand.

[0027] The molar concentration of photocatalyst (C) can be from 0.01 mol.% to 15 mol.%, more preferably from 0.05 mol.% to 10 mol.%, more preferably from 0.1 mol.% to 5 mol.%, even more preferably from 0.5 mol.% to 2 mol.%, relative to the total number of moles of unsaturations carried by the unsaturated compound (A). According to a preferred variant, in the process according to the invention, no compounds based on platinum, palladium, ruthenium or rhodium are used. The quantity of compounds based on platinum, palladium, ruthenium or rhodium in the reaction medium is, for example, less than 0.1% by weight relative to the weight of the photocatalyst (C), preferably less than 0.01% by weight, and more preferably less than 0.001% by weight.

[0028] The present invention consists firstly of a process for the hydrosilylation of an unsaturated compound (A) comprising at least one monosubstituted alkene function, with a compound (B) comprising at least one hydrogenosilyl function, said process comprising the step of subjecting said unsaturated compound (A) and said compound (B) to irradiation in the presence of a photocatalyst (C) as described above.

[0029] The unsaturated compound (A) used in the hydrosilylation process according to the invention is a chemical compound comprising at least one monosubstituted alkene unsaturation not forming part of an aromatic cycle. It can be chosen from those known to those skilled in the art and which do not contain a reactive chemical function which could hinder or even prevent the hydrosilylation reaction.

[0030] In the present text, the term "monosubstituted alkene" or "monosubstituted alkenyl" means a covalent double bond between two carbon atoms, not forming part of an aromatic cycle, the two carbon atoms being linked to 3 hydrogen atoms and a monovalent radical different from the hydrogen atom. The unsaturated compound (A) used in the hydrosilylation process according to the invention can be represented by the general formula (I): RCH=CH2 (I) in which R represents a monovalent radical.

[0031] According to one embodiment, the unsaturated compound (A) comprises one or more monosubstituted alkene functions and from 2 to 40 carbon atoms. The unsaturated compound (A) can be represented by the general formula (I): RCH=CH2 (I) in which R represents a monovalent radical chosen from the group consisting of - an alkyl group having between 1 and 30 carbon atoms, more preferably between 1 and 12 carbon atoms, even more preferably between 1 and 6 carbon atoms, optionally substituted by one or more halogen atoms such as chlorine or fluorine, and optionally by one or more groups chosen from -OH and -OSiR'3, in which each R' represents, independently of one another, H or an alkyl group; - an aryl group having between 6 and 30 carbon atoms, more preferably between 6 and 18 carbon atoms, optionally substituted by one or more halogen atoms such as chlorine or fluorine, and optionally by one or more groups selected from -OH and -OSiR'3, in which each R' represents, independently of one another, H or an alkyl group; - an aryl-alkyl group preferably comprises between 6 and 30 carbon atoms, more preferably between 7 and 20 carbon atoms, optionally substituted on its aryl part and / or on its alkyl part by one or more halogen atoms such as chlorine or fluorine, and optionally by one or more groups chosen from -OH and -OSiR'3, in which each R' represents, independently of one another, H or an alkyl group; - an ether group of formula -LOR”, in which L represents a bond or a divalent radical, preferably an alkylene group having from 1 to 12 carbon atoms, even more preferably between 1 and 6 carbon atoms, and R' ' represents a group chosen from: an alkyl group having between 1 and 30 carbon atoms, more preferably between 1 and 12 carbon atoms, even more preferably between 1 and 6 carbon atoms, optionally substituted by one or more halogen atoms such as chlorine or fluorine, and optionally by one or more groups chosen from -OH and -OSiR'3, in which each R' represents, independently of one another, H or an alkyl group;an aryl group having between 6 and 30 carbon atoms, more preferably between 6 and 18 carbon atoms, optionally substituted by one or more halogen atoms such as chlorine or fluorine, and optionally by one or more groups chosen from -OH and -OSiR'3, in which each R' represents, independently of one another, H or an alkyl group; and an aryl-alkyl group preferably comprises between 6 and 30 carbon atoms, more preferably between 7 and 20 carbon atoms, optionally substituted on its aryl part and / or on its alkyl part by one or more halogen atoms such as chlorine or fluorine, and optionally by one or more groups chosen from -OH and -OSiR'3, in which each R' represents, independently of one another, H or an alkyl group; ; - an ester group of formula -LOC(O)-R”, in which L and R” have the same definition as given above.

[0032] The unsaturated compound (A) may, preferably, be an organic compound comprising a monosubstituted alkene group chosen from the group consisting of: - α-olefins, preferably 1-octene and 1-hexene, - chlorinated α-olefins, preferably allyl chloride, - fluorinated α-olefins, preferably 4,4,5,5,6,6,7,7,7-nonafluoro-1-heptene, - allyl alcohol, - allyl ethers, such as allyl benzyl ether, allyl C1-C8 alkyl ethers, allyl glycidyl ether, allyl piperidine ether, preferably sterically hindered allyl piperidine ether, ethers

[0033]

[0034]

[0035] allyl and silyl, preferably allyl and trimethylsilyl ether, - allyl esters, such as allyl acetate, - styrenes, - 1,2-epoxy-4-vinylcyclohexane, - C1 to C4 alkyl acrylates and acrylic acid. The unsaturated compound (A) may be a disiloxane, such as vinyl pentamethyl disiloxane and divinyl tetramethyl disiloxane. The unsaturated compound (A) may be chosen from compounds comprising several monosubstituted alkene functions, preferably two or three monosubstituted alkene functions, and particularly preferably, the compound (A) is chosen from the following compounds:

[0036]

[0037] According to a particularly preferred embodiment, the unsaturated compound (A) may be an organopolysiloxane compound comprising one or more monosubstituted alkene functions, preferably at least two monosubstituted alkene functions. The hydrosilylation reaction of alkenes is one of the key reactions in silicone chemistry. It allows not only the crosslinking between organopolysiloxanes with SiH functions and organopolysiloxanes with alkenyl functions to form networks and provide mechanical properties to the materials, but also the functionalization of organopolysiloxanes with SiH functions to modify their physical and chemical properties. Said organopolysiloxane compound can in particular be formed: - at least two siloxyl units of the following formula: YaR1bSiO(4_a_b) / 2 in which: Y is a C2-C12 monosubstituted alkenyl group, preferably vinyl, R1 is a monovalent hydrocarbon group having from 1 to 12 carbon atoms, preferably selected from alkyl groups having from 1 to 8 carbon atoms such as methyl, ethyl, propyl groups, cycloalkyl groups having from 3 to 8 carbon atoms and aryl groups having from 6 to 12 carbon atoms, and a=1, 2 or 3, preferably a=1 or 2, more preferably a=1; b=0, 1 or 2; and the sum a+b=1, 2 or 3; and - possibly patterns of the following formula: R1cSiO(4_c) / 2 in which R1 has the same meaning as above and c = 0, 1, 2 or 3.

[0038] It is understood in the above formulas that, if several R1 groups are present or if several Y groups are present, they may be identical or different from each other. Preferably R1 may represent a monovalent radical chosen from the group consisting of alkyl groups having 1 to 8 carbon atoms, optionally substituted by at least one halogen atom such as chlorine or fluorine, cycloalkyl groups having from 3 to 8 carbon atoms and aryl groups having from 6 to 12 carbon atoms. R1 may advantageously be chosen from the group consisting of methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl.

[0039] These organopolysiloxane compounds comprising one or more monosubstituted alkene functions may have a linear structure, a cyclic structure or a branched structure.

[0040] In the present invention: - a siloxyl unit “Mvi” represents a siloxyl unit of formula YR^SiOi^ or Y2 R*SiO1 / 2, - a siloxyl unit “M” represents a siloxyl unit of formula R^SiOi^, - a siloxyl unit “Dvi” represents a siloxyl unit of formula YR'SiO^, - a siloxyl unit “D” represents a siloxyl unit of formula R12SiO2 / 2, - a siloxyl unit “T” represents a siloxyl unit of formula R'SiOa^, - a siloxyl unit “Q” represents a siloxyl unit of formula SiO4 / 2, the symbols Y and R1 being as described above.

[0041] As examples of terminal “M” and “Mvi” units, mention may be made of trimethylsiloxy, dimethylphenylsiloxy, dimethylvinylsiloxy or dimethylhexenylsiloxy groups.

[0042] As examples of “D” and “Dvi” units, mention may be made of the dimethylsiloxy, methylphenylsiloxy, methylvinylsiloxy, methylbutenylsiloxy, methylhexenylsiloxy, methyldecenylsiloxy or methyldecadienylsiloxy groups.

[0043] Linear organopolysiloxane compounds comprising one or more monosubstituted alkene functions are essentially composed of siloxyl units “D” and “Dvi” and siloxyl units “M” and “Mvi”. Examples of linear organopolysiloxanes which may be organopolysiloxane compounds comprising one or more monosubstituted alkene functions according to the invention are: - a poly(dimethylsiloxane) with dimethylvinylsilyl ends; - a poly(dimethylsiloxane-co-methylphenylsiloxane) with dimethyl-vinylsilyl ends; - a poly(dimethylsiloxane-co-methylvinylsiloxane) with dimethyl-vinylsilyl ends; and - a poly(dimethylsiloxane-co-methylvinylsiloxane) with trimethylsilyl ends.

[0044] In the most preferred form, the organopolysiloxane compound comprising one or more monosubstituted alkene functions contains terminal dimethylvinylsilyl units. Even more preferably, the organopolysiloxane compound comprising one or more monosubstituted alkene functions is a poly(dimethylsiloxane) with dimethylvinylsilyl ends.

[0045] A silicone oil generally has a viscosity of between 1 mPa.s and 2,000,000 mPa.s. Preferably, said organopolysiloxane compounds comprising one or more alkene functions are silicone oils with a dynamic viscosity of between 20 mPa.s and 100,000 mPa.s, preferably between 20 mPa.s and 80,000 mPa.s at 25°C, and more preferably between 100 mPa.s and 50,000 mPa.s.

[0046] The cyclic organopolysiloxane compounds comprising one or more monosubstituted alkene functions are essentially composed of siloxyl units “D” and “Dvi” as described above. An example of a cyclic organopolysiloxane which may be an organopolysiloxane compound comprising one or more monosubstituted alkene functions according to the invention is cyclic poly(methylvinylsiloxane).

[0047] Optionally, the organopolysiloxane compounds comprising one or more monosubstituted alkene functions may further contain “T” siloxyl units and / or “Q” siloxyl units. The organopolysiloxane compounds comprising one or more monosubstituted alkene functions then have a branched structure. Examples of branched organopolysiloxanes, also called resins, which may be organopolysiloxane compounds comprising one or more monosubstituted alkene functions according to the invention are: - MDviQ, where the vinyl groups are included in the D units, - MDviTQ, where the vinyl groups are included in the D units, - MMviQ, where the vinyl groups are included in a part of the M units, - MMviTQ, where the vinyl groups are included in a part of the M units, - MMviDDviQ, where the vinyl groups are included in a part of the M and D units, - and mixtures thereof.

[0048] Preferably, the organopolysiloxane compound comprising one or more monosubstituted alkene functions has a mass content of monosubstituted alkenyl unit of between 0.001% and 30%, preferably between 0.01% and 10%, of preferably between 0.02 and 5%.

[0049] The unsaturated compound (A) reacts according to the present invention with a compound (B) comprising at least one hydrogenosilyl function.

[0050] According to one embodiment, the compound (B) comprising at least one hydrogenosilyl function is a silane or polysilane compound comprising at least one hydrogen atom bonded to a silicon atom. By "silane" compound is meant in the present invention the chemical compounds comprising a silicon atom bonded to four hydrogen atoms or to organic substituents. By compound "polysilane" means in the present invention chemical compounds having at least one =Si-Si= unit. Among the silane compounds, compound (B) comprising at least one hydrogenosilyl function may be phenylsilane or a mono-, di- or tri-alkylsilane, for example triethylsilane.

[0051] According to another embodiment, the compound (B) comprising at least one hydrogenosilyl function is an organopolysiloxane compound comprising at least one hydrogen atom bonded to a silicon atom, also called organohydrogenpolysiloxane. Said organohydrogenpolysiloxane may advantageously be an organopolysiloxane formed: - at least two siloxyl units of the following formula: HdR1eSiO(4 de) / 2 in which: R1 is a monovalent hydrocarbon group having from 1 to 12 carbon atoms, preferably selected from alkyl groups having from 1 to 8 carbon atoms such as methyl, ethyl, propyl groups, cycloalkyl groups having from 3 to 8 carbon atoms and aryl groups having from 6 to 12 carbon atoms, and d=1, 2 or 3, preferably d=1 or 2, more preferably d=1; e=0, 1 or 2; and d+e=1, 2 or 3; and - possibly other patterns of the following formula: R1fSiO(4_f) / 2 in which R1 has the same meaning as above, and f = 0, 1, 2, or 3.

[0052] It is understood in the above formulas that, if several R1 groups are present, they may be identical or different from each other. Preferably, R1 may represent a monovalent radical chosen from the group consisting of alkyl groups having 1 to 8 carbon atoms, optionally substituted by at least one halogen atom such as chlorine or fluorine, cycloalkyl groups having from 3 to 8 carbon atoms and aryl groups having from 6 to 12 carbon atoms. R1 may advantageously be chosen from the group consisting of methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl.

[0053] The organohydrogenpolysiloxane may have a linear, branched, or cyclic structure. The degree of polymerization is preferably greater than or equal to 2. Generally, it is less than 5000.

[0054] In the following, the siloxyl units “M”, “D”, “T” and “Q” are as previously defined, and - the siloxyl units “M'” represents a siloxyl unit of formula HR^SiOi^, - the siloxyl units “D'” represents a siloxyl unit of formula HR'SiC^, the symbol R1 being as described above.

[0055] When linear polymers are concerned, these essentially consist of siloxyl units chosen from the siloxyl units “D” and “D'”, and of terminal siloxyl units “M” and “M'”. Examples of organohydrogenopolysiloxanes which may be compounds (B) comprising at least one hydrogenosilyl function according to the invention are: - a poly(dimethylsiloxane) with hydrogenodimethylsilyl ends; - a poly(dimethylsiloxane-co-methylhydrogensiloxane) with trimethylsilyl ends; - a poly(dimethylsiloxane-co-methylhydrogensiloxane) with hydrogenodimethylsilyl ends; and - a poly(methylhydrogensiloxane) with trimethylsilyl ends.

[0056] When the organohydrogenpolysiloxane has a cyclic structure, it is essentially composed of siloxyl units chosen from the siloxyl units “D” and “D'”. An example of a cyclic organohydrogenpolysiloxane which may be a compound (B) comprising at least one hydrogenosilyl function according to the invention is a cyclic poly(methylhydrogensiloxane).

[0057] When the organohydrogenpolysiloxane has a branched structure, it is preferably chosen from the group consisting of silicone resins of the following formulas: - M'Q where the hydrogen atoms linked to silicon atoms are carried by the M groups, - MM'Q where the hydrogen atoms linked to silicon atoms are carried by part of the M motifs, - MD'Q where the hydrogen atoms linked to silicon atoms are carried by the D groups, - MDD'Q where the hydrogen atoms linked to silicon atoms are carried by part of the D groups, - MM'TQ where the hydrogen atoms linked to silicon atoms are carried by part of the M motifs, - MM'DD'Q where the hydrogen atoms linked to silicon atoms are carried by part of the M and D motifs, - and their mixtures.

[0058] Preferably, the organohydrogenpolysiloxane compound has a mass content of hydrogenosilyl Si-H functions between 0.2% and 91%, more preferably between 3% and 80%, and even more preferably between 15% and 70%.

[0059] According to a particular embodiment of the present invention, it is possible for the unsaturated compound (A) and the compound (B) comprising at least one hydrogenosilyl function to be one and the same compound, comprising on the one hand at least one monosubstituted alkene function, and on the other hand at least one silicon atom and at least one hydrogen atom bonded to the silicon atom. This compound can then be described as "bifunctional", and it is capable of reacting with itself by hydrosilylation reaction. The invention can therefore also relate to a process for hydrosilylation of a bifunctional compound with itself, said bifunctional compound comprising on the one hand at least one monosubstituted alkene function, and on the other hand at least one silicon atom and at least one hydrogen atom bonded to the silicon atom, said process being photocatalyzed by the photocatalyst (C) as described above.

[0060] Examples of organopolysiloxanes that may be bifunctional compounds are: - a poly(dimethylsiloxane-co-hydrogenomethylsiloxane-co-vinylmethyl-siloxanes) with dimethylvinylsilyl ends; - a poly(dimethylsiloxane-co-hydrogenomethylsiloxane-co-vinylmethyl-siloxanes) with dimethylhydrogenosilyl ends; and - A poly(dimethylsiloxane-co-hydrogenomethylsiloxane-co-propylglycidylethermethylsiloxane) with trimethylsilyl ends.

[0061] When it comes to the implementation of the unsaturated compound (A) and the compound (B) comprising at least one hydrogenosilyl function, the person skilled in the art understands that this also means the implementation of a bifunctional compound.

[0062] The amounts of compound (A) and compound (B) may be controlled so that the molar ratio of the hydrogenosilyl functions of compounds (B) to the monosubstituted alkene functions of compounds (A) is preferably between 1:10 and 10:1, more preferably between 1:5 and 5:1, more preferably between 1:3 and 3:1, and even more preferably between 1:2 and 2:1.

[0063] The method according to the present invention comprises the step of subjecting said unsaturated compound (A) and said compound (B) to irradiation in the presence of the photocatalyst (C).

[0064] The irradiation is preferably an exposure to UV and / or visible radiation. In the present text, "UV" means ultraviolet. Ultraviolet radiation is defined as electromagnetic radiation whose wavelength is between approximately 100 nm and approximately 400 nm, i.e. below the visible light spectrum. Within UV, UV-A can be defined, whose wavelength is between about 315 nm and about 400 nm, UV-B, whose wavelength is between about 280 nm and about 315 nm, and UV-C, whose wavelength is between about 100 nm and about 280 nm. Visible radiation is defined as electromagnetic radiation whose wavelength is between about 400 nm and about 800 nm. Preferably, the irradiation is carried out by exposure to radiation with a wavelength between 100 nm and 450 nm, or between 200 nm and 420 nm, or between 250 nm and 405 nm.

[0065] The radiation may be emitted by doped or undoped mercury vapor lamps whose emission spectrum extends from 100 nm to 450 nm. Light sources such as LEDs which deliver point UV or visible light may also be used. Furthermore, in the present text, "LED" is the abbreviation well known to those skilled in the art for "light-emitting diode" (also DEL in French).

[0066] According to one embodiment, the irradiation is carried out with UV radiation whose source is a UV-LED lamp. Said UV-LED lamp can emit radiation of wavelength 365 nm, 385 nm, 395 nm or 405 nm. Preferably, the UV-LED lamp is a lamp emitting at 395 nm. The power of the UV-LED lamp is preferably between 2 W / m2 and 200,000 W / m2.

[0067] According to a preferred embodiment, the irradiation step is carried out under an inert atmosphere, for example under nitrogen, under argon or under oxygen-depleted air.

[0068] The irradiation step is carried out at a temperature between 0°C and 60°C, more preferably between 15°C and 60°C, more preferably between 20°C and 40°C, and even more preferably at room temperature, typically around 25°C.

[0069] The hydrosilylation reaction can be carried out in a solvent or in the absence of a solvent. Suitable solvents are solvents miscible with the compound (B). For example, the solvent can be selected from the group consisting of aliphatic hydrocarbons, such as pentane, hexane, heptane, cyclohexane, decalin, and paraffin oils; aromatic hydrocarbons, such as toluene, and xylene; mixtures of hydrocarbons of mineral or synthetic origin, such as white spirit; ethers, such as tetrahydrofuran, dioxane, diethyl ether and diphenyl ether; chlorinated hydrocarbons, such as methylene chloride, 1,2-dichloroethane, perchloroethylene and chlorobenzene; esters, such as ethyl acetate, butyl acetate and butyrolactone; acetonitrile; dimethylformamide; dimethylsulfoxide; N-methylpyrrolidone; polyethylene glycols; and mixtures thereof.Preferably, the solvent may be selected from the group consisting of aliphatic hydrocarbons, aromatic hydrocarbons and chlorinated hydrocarbons, and more preferably from the group consisting of hexane, cyclohexane, decalin, and toluene. Alternatively, the solvent may be selected from the group consisting of . volatile silicones, octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), polydimethylsiloxane oils (PDMS), polyphenylmethylsiloxane oils (PPMS) or mixtures thereof. Alternatively, one of the reactants, for example the unsaturated compound (A), may act as a solvent. Preferably, the use of organic solvents that are harmful to the environment and the health of workers in manufacturing workshops will be avoided.

[0070] According to a preferred embodiment of the invention, the compounds (A) and (B) used are chosen from organopolysiloxanes as defined above. In this case, a three-dimensional network is formed, which leads to the curing of the composition. Crosslinking involves a progressive physical change in the medium constituting the composition. Consequently, the process according to the invention can be used to obtain elastomers, gels, foams, etc. In this case, a crosslinked silicone material is obtained. The term "crosslinked silicone material" means any silicone-based product obtained by crosslinking and / or curing of compositions comprising organopolysiloxanes having at least two unsaturated bonds and organopolysiloxanes having at least three hydrogenosilylated units. The crosslinked silicone material can, for example, be an elastomer, a gel or a foam.

[0071] Still according to this preferred embodiment of the process according to the invention, where the compounds (A) and (B) are chosen from organopolysiloxanes as defined above, it is possible to use usual functional additives in silicone compositions. As families of usual functional additives, mention may be made of: - fillers, - adhesion promoters, - inhibitors or retarders of the hydrosilylation reaction, - adhesion modulators, - silicone resins, - additives for increasing consistency, - pigments (organic or mineral), and - additives for thermal resistance, oil resistance or fire resistance, for example metal oxides.

[0072] The filler that may be provided is preferably mineral. The filler may be a very finely divided product with an average particle diameter of less than 0.1 μm. The filler may in particular be siliceous. With regard to siliceous materials, they may act as reinforcing or semi-reinforcing fillers. The reinforcing siliceous fillers are chosen from colloidal silicas, combustion and precipitation silica powders or mixtures thereof. These powders have an average particle size generally less than 0.1 μm (micrometers) and a BET specific surface area greater than 30 m2 / g, preferably between 30 and 350 m2 / g. Semi-reinforcing siliceous fillers such as diatomaceous earth or ground quartz may also be used. These silicas may be incorporated as such or after being treated with organosilicon compounds commonly used for this purpose. These compounds include methylpolysiloxanes such as hexamethyldisiloxane, octamethylcyclotetrasiloxane, methylpolysilazanes such as hexamethyldisilazane, hexamethylcyclotrisilazane, tetramethyldivinyldisilazane, chlorosilanes such as dimethyldichlorosilane, trimethylchlorosilane, methylvinyldichlorosilane, dimethylvinylchlorosilane, alkoxysilanes such as dimethyldimethoxysilane, dimethylvinylethoxysilane, trimethylmethoxysilane, and mixtures thereof. As for non-siliceous mineral materials, they can be used as semi-reinforcing or bulking mineral fillers.Examples of these non-siliceous fillers that can be used alone or in a mixture are calcium carbonate, optionally surface-treated with an organic acid or an ester of an organic acid, calcined clay, rutile-type titanium oxide, iron, zinc, chromium, zirconium, magnesium oxides, different forms of alumina (hydrated or not), boron nitride, lithopone, barium metaborate, barium sulfate and glass microbeads. These fillers are coarser, generally with an average particle diameter greater than 0.1 μm and a specific surface area generally less than 30 m2 / g. These fillers may have been surface-modified by treatment with the various organosilicon compounds usually used for this purpose. Preferably, the filler is silica, and even more preferably combustion silica. Advantageously, the silica has a BET specific surface area of between 75 and 410 m2 / g.A silicone composition may comprise between 5 and 20% by weight of filler relative to the total weight of the silicone composition. Advantageously, the silicone composition may comprise between 8 and 15% by weight of filler.

[0073] The discovery of this new photocatalyzed hydrosilylation process under mild conditions according to the present invention makes it possible to envisage numerous applications.

[0074] According to a first embodiment, the hydrosilylation process according to the present invention can be used for the functionalization of organopolysiloxanes with SiH functions. The functionalization aims to modify the physical and / or chemical properties of said organopolysiloxanes, and to produce new compounds with improved properties. According to this embodiment, the unsaturated compound (A) comprising at least one monosubstituted alkene function is chosen from unsaturated compounds comprising one or more monosubstituted alkene functions and from 2 to 40 carbon atoms, and the compound (B) comprising at least one hydrogenosilyl function is an organopolysiloxane compound comprising at least one atom of hydrogen bonded to a silicon atony. A process for functionalizing organopolysiloxanes with SiH functions can be described, characterized in that the addition reaction between organopolysiloxanes with SiH functions and unsaturated compounds (A) comprising one or more monosubstituted alkene functions and from 2 to 40 carbon atoms is obtained by the hydrosilylation process as described above.

[0075] According to another particularly preferred embodiment, the hydrosilylation method according to the present invention can be used for crosslinking between organopolysiloxanes with SiH functions and organopolysiloxanes with alkenyl functions to form networks and provide mechanical properties to the materials. According to this embodiment, the unsaturated compound (A) comprising at least one monosubstituted alkene function is an organopolysiloxane compound comprising at least two monosubstituted alkene functions, and the compound (B) comprising at least one hydrogenosilyl function is an organopolysiloxane compound comprising at least three hydrogen atoms bonded to a silicon atom.A process for preparing crosslinked silicone materials can be described, characterized in that the crosslinking reaction between organopolysiloxanes with SiH functions and organopolysiloxanes with alkenyl functions is obtained by the hydrosilylation process as described above. The crosslinked silicone materials thus obtained can be used in various applications, in particular: . - “coating” type applications, where a support is covered with a silicone coating; - applications in the field of electronics, for example for the preparation of conformal coatings for printed circuits, and for the filling of microcircuits and electronic components such as IGBTs; - additive manufacturing processes (also known as 3D printing processes) using photopolymerization.

[0076] Other details or advantages of the invention will appear more clearly in view of the examples given below for information purposes only. Examples

[0077] Examples 1-3 and Comparatives 1-3: Hydrosilvation of 1-octene (1) with LLL3.5.5.5-heptamethvl-trisiloxane (2)

[0078] rp MrijP CH3 W * lCh ' 3| -o ■ vqvj 1 ï 3 4

[0079] 1-Octene (1) and 1,1,1,3,5,5,5-heptamethyl-trisiloxane (2) were introduced into a 4 mL vial under an argon atmosphere at room temperature. A solution of de- Dimanganese carbonyl Mn2(CO)i0 in toluene was injected into the vial and toluene was added. Final concentration of Mn2(CO)i0 (relative to 1-octene) = 1 mol%.

[0080] In Examples 1, 2 and 3, the reaction mixture was placed under UV light for 4 hours (300 W, X = 250-420 nm). In Comparative Examples 1, 2 and 3, the reaction mixture was not irradiated, but was heated for 24 hours. The concentrations of the reactants and the reaction conditions are as indicated in Table 1, as well as the yields of the hydrosilylation product (3) and the product of the isomerization of (1) (determined by gas chromatography, calculated relative to 1-octene).

[0081] [Tables 1] Conditions Conc. (1) Conc. (2) Yield in (3) Isomerization of (1) Ex.l UV, 4 h 0.825 M 1.650 M 94% no product Ex.2 UV, 4 h 1.650 M 1.650 M 78% 1% Ex. 3 UV, 4 h 3.3 M 1.650 M 86% 3% Comp.l 30°C, 24 h 0.825 M 1.650 M no product no product Comp.2 60°C, 24 h 0.852 M 1.650 M no product no product Comp.3 100°C, 24 h 0.825 M 1.650 M no product no product

[0082] Examples 1, 2 and 3 show that the hydrosilylation reaction between 1-octene (1) and 1,1,1,3,5,5,5-heptamethyl-trisiloxane (2) photocatalyzed by Mn2(CO)i0 makes it possible to obtain a product (3) with excellent yield and excellent selectivity, under mild reaction conditions (4 hours at room temperature). Conversely, the catalyst does not show activity by thermal activation (comparative examples 1, 2 and 3).

[0083] Examples 4-12 and Comparatives 4-6: Hydrosilylation of different alkenes 11'1

[0084] ÇH» ,ÇHS p - 1CH b S|'O sn vhv 'j - T 2 T [J

[0085] The same procedure described in Example 1 (UV, 4h) was followed by varying the structure of the alkene compound (1') as indicated in Table 2 below. The yield of hydrosilylation product (3') (determined by gas chromatography, calculated relative to T alkene) is indicated in Table 2.

[0086] [Tables2] Alkene (1') Yield in (3') Ex.4 5 94% Ex. 5 '3 >99% Ex. 6 >99% Ex.7 >99% Ex. 8 y. j 80% Ex.9 0,^ >99% Ex. 10 >0.. ;?Bu --¾ 70% Ex. 11 77% Ex. 12 Â .... O 47% Comp.4 J no product Comp.5 s ***** no product Comp.6 no product

[0087] In Examples 4 to 12, the hydrosilylation products were obtained with excellent selectivity. No C=C isomerization or C-O bond scission product was observed. On the other hand, the hydrosilylation product is not obtained from gem-disubstituted alkenes (Comparative Examples 4 and 5) or from internal alkene (Comparative Example 6).

Claims

Claims

1. A process for the hydrosilylation of an unsaturated compound (A) comprising at least one monosubstituted alkene function, with a compound (B) comprising at least one hydrogenosilyl function, said process comprising the step of subjecting said unsaturated compound (A) and said compound (B) to irradiation in the presence of a photocatalyst (C) consisting of a manganese carbonyl.

2. Hydrosilylation process according to claim 1, characterized in that the manganese carbonyl is dimanganese decacarbonyl, of chemical formula [Mn2(CO)i0].

3. A hydrosilylation process according to claim 1 or claim 2, characterized in that the unsaturated compound (A) is an organic compound comprising a monosubstituted alkene group selected from the group consisting of: - α-olefins, preferably 1-octene and 1-hexene, - chlorinated α-olefins, preferably allyl chloride, - fluorinated α-olefins, preferably 4,4,5,5,6,6,7,7,7-nonafluoro-1-heptene, - allyl alcohol, - allyl ethers, such as allyl benzyl ether, allyl C1-C8 alkyl ethers, allyl glycidyl ether, allyl piperidine ether, preferably allyl piperidine ether sterically hindered, allyl silyl ethers, preferably allyl trimethylsilyl ether, - allyl esters, such as allyl acetate, - styrenes, - 1,2-epoxy-4-vinylcyclohexane, - C1-C4 alkyl acrylates and acrylic acid.

4. Hydrosilylation process according to claim 1 or claim 2, characterized in that the unsaturated compound (A) is an organopo-lysiloxane compound comprising one or more monosubstituted alkene functions, preferably at least two monosubstituted alkene functions.

5. Hydrosilylation process according to any one of claims 1 to 4, characterized in that the compound (B) comprising at least one hydrogenosilyl function is an organopolysiloxane compound comprising at least one hydrogen atom bonded to a silicon atom.

6. Hydrosilylation process according to any one of claims 1 to 5, characterized in that the irradiation is carried out by exposure to radiation with a wavelength between 100 nm and 450 nm, or between 200 nm and 420 nm, or between 250 nm and 405 nm.

7. Hydrosilylation process according to any one of claims 1 to 6, characterized in that the irradiation is carried out with UV radiation, the source of which is a UV-LED lamp.

8. Hydrosilylation process according to any one of claims 1 to 7, characterized in that the irradiation is carried out at a temperature between 0°C and 60°C, more preferably between 15°C and 60°C, more preferably between 20°C and 40°C, and even more preferably at room temperature.

9. Hydrosilylation process according to any one of claims 1, 2, 6, 7 and 8, for the functionalization of organopolysiloxanes with SiH functions, characterized in that the unsaturated compound (A) comprising at least one monosubstituted alkene function is chosen from unsaturated compounds comprising one or more monosubstituted alkene functions and from 2 to 40 carbon atoms, and the compound (B) comprising at least one hydrogenosilyl function is an organopolysiloxane compound comprising at least one hydrogen atom bonded to a silicon atom.

10. Hydrosilylation process according to any one of claims 1, 2, 6, 7 and 8, for the preparation of crosslinked silicone materials, characterized in that the unsaturated compound (A) comprising at least one monosubstituted alkene function is an organopolysiloxane compound comprising at least two monosubstituted alkene functions, and the compound (B) comprising at least one hydrogenosilyl function is an organopolysiloxane compound comprising at least three hydrogen atoms linked to a silicon atom.

11. Use of a manganese carbonyl as a photocatalyst for a hydrosilylation reaction of an unsaturated compound (A) comprising at least one monosubstituted alkene function, with a compound (B) comprising at least one hydrogenosilyl function.