Hydrosilylation process photocatalyzed by manganese complexes

Abstract

The present invention relates to a hydrosilylation reaction between a monosubstituted alkene compound and a compound containing at least one hydrogen atom bonded to a silicon atom. More specifically, the present invention relates to a method for hydrosilylation of an unsaturated compound (A) containing at least one monosubstituted alkene functional group with a compound (B) containing at least one hydrosilyl functional group, the method comprising a step of irradiating the unsaturated compound (A) and the compound (B) in the presence of a photocatalyst (C) consisting of manganese carbonyl. The hydrosilylation reaction between an alkene compound and a compound containing at least one hydrogen atom bonded to a silicon atom makes it possible in particular to cure silicone compositions by crosslinking.

Description

[Technical field]

[0001] The present invention relates to a hydrosilylation reaction between a monosubstituted alkene compound and a compound containing at least one hydrogen atom bonded to a silicon atom. More specifically, the present invention relates to a hydrosilylation method photocatalyzed by a manganese complex. The hydrosilylation reaction between an alkene compound and a compound containing at least one hydrogen atom bonded to a silicon atom allows the silicone composition to be cured by crosslinking in particular. [Background technology]

[0002] State of the art During the hydrosilylation reaction (also known as polyaddition) of alkene compounds, a compound containing at least one double bond reacts with a compound containing at least one hydrosilyl functional group, i.e., a hydrogen atom bonded to a silicon atom. This reaction can be described, for example, by the following equation: [ka]

[0003] The hydrosilylation reaction may be accompanied by or may be replaced by a dehydrogenative silylation reaction (also known as dehydrosilylation), which can be described by the following equation: [ka]

[0004] The hydrosilylation reaction is used in particular to crosslink silicone compositions that contain organopolysiloxanes having alkenyl units and organopolysiloxanes having hydrosilyl functional groups.

[0005] The hydrosilylation reaction of alkene compounds is typically carried out by catalysis using metal or organometallic catalysts. Currently, the catalyst suitable for this reaction is a platinum catalyst. Thus, the majority of industrial hydrosilylation processes, especially for the hydrosilylation of alkenes, are catalyzed by Speier hexachloroplatinic acid or Karstedt Pt(0) complexes of the general formula Pt2(divinyltetramethyldisiloxane)3 (or abbreviated as Pt2(DVTMS)3).

[0006] In the 2000s, more stable catalysts became available through the preparation of platinum-carbene complexes (see, for example, WO 01 / 42258).

[0007] However, the use of metallic or organometallic platinum catalysts still has problems. Platinum is an expensive metal, its scarcity is increasing and its cost is rising enormously. This makes its use on an industrial scale difficult. It is therefore desirable to reduce the amount of catalyst required for the reaction as much as possible without reducing the yield or reaction rate. Numerous studies have been carried out to find alternatives to the Karstedt catalyst.

[0008] For example, WO 2014 / 096719 describes a method for the hydrosilylation of an unsaturated compound with a hydrosilane compound, catalyzed by a photocatalyst selected from polyoxometalates, such as tetrabutylammonium decatungstate.

[0009] The problem of replacing chloroplatinic acid as a hydrosilylation catalyst was already mentioned in U.S. Patent No. 3,271,362 in 1966. The inventors of that patent proposed cyclopentadienylcobalt dicarbonyl [C5H5Co(CO)2], dimanganese decacarbonyl [Mn2(CO) 10They proposed the use of a metal carbonylation catalyst selected from the group consisting of dimanganese decacarbonyl [Co2(CO)8] and dicobalt octacarbonyl [Co2(CO)8]. In the only embodiment using dimanganese decacarbonyl, the reaction is carried out at 125° C., and no precise information is given regarding the yield of the reaction and the nature of the polyaddition product.

[0010] In 2021, Dong et al. described a manganese-based catalyst for the dehydrosilylation and hydrosilylation of alkenes in a scientific paper ("Manganese-catalysed divergent silylation of alkenes", Nature Chemistry, Vol. 13, p. 182-190 (2021)). Mn2(CO) 10 is used as the metal precursor and must be combined with a ligand, preferably a JackiePhos ligand, to promote the hydrosilylation reaction. The reaction is carried out at 120 °C.

[0011] Dimanganese decacarbonyl has also been used as a catalyst in other reactions. For example, 10 mol% Mn(CO) was used as a photocatalyst for the hydrosilylation of alkynes. 10 A scientific paper by Liang et al. ("Visible-Light-Initiated Manganese-Catalyzed E-Selective Hydrosilylation and Hydrogermylation of Alkynes", Org. Lett., 2019, 21, 8, 2750-2754) describes the use of . Unlike alkenes, alkynes cannot undergo dehydrosilylation. Regarding dehydrosilylation, the scientific paper by Stefan Weber ("Manganese-Catalyzed Dehydrogenative Silylation of Alkenes Following Two Parallel Inner-Sphere Pathways", J. Am. Chem. Soc., 2021, 143, 17825-17832) describes the use of Mn(I) catalysts for the dehydrogenative silylation of terminal alkenes. Two catalysts are proposed: fac-[Mn(dippe)(CO)3(CH2CH2CH3)] and fac-[Mn(ddre)(CO)3(CH2CH2CH3)] (dippe = 1,2-bis(diisopropylphosphino) and drpe = 1,2-bis(di-n-propylphosphino)).

[0012] In this context, the inventors have sought a more effective process for the hydrosilylation of alkene compounds. Advantageously, it would be desirable for the reaction to be rapid and to take place at moderate temperatures, preferably at ambient temperature. Furthermore, it would be desirable for the hydrosilylation reaction to be selective and for the dehydrosilylation and / or isomerization reactions of the alkene compounds to be reduced, even negligible. Finally, it would be desirable for the catalyst to comprise abundant, inexpensive, and non-toxic chemical elements. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] WO 01 / 42258 [Patent Document 2] International Publication No. 2014 / 096719 [Patent Document 3] U.S. Pat. No. 3,271,362 [Non-patent literature]

[0014] [Non-Patent Document 1] Dong et al., "Manganese-catalysed divergent silylation of alkenes," Nature Chemistry, Vol. 13, p. 182-190 (2021) [Non-Patent Document 2] Liang et al., “Visible-Light-Initiated Manganese-Catalyzed E-Selective Hydrosilylation and Hydrogermylation of Alkyne”, Org. Lett., 2019, 21, 8, 2750-2754 [Non-Patent Document 3] Stefan Weber, “Manganese-Catalyzed Dehydrogenative Silylation of Alkenes Following Two Parallel Inner-Sphere Pathways”, J.Am.Chem.Soc.,2021,143,17825-17832 Summary of the Invention [Problem to be solved by the invention]

[0015] Summary of the Invention Unexpectedly, the present inventors have discovered that the hydrosilylation reaction of mono-substituted alkenes can be photocatalyzed by manganese carbonyl complexes under mild conditions in excellent yields and with excellent selectivity, and in particular, the photocatalysis produces little or no dehydrosilylation and / or isomerization products of the mono-substituted alkene compounds. [Means for solving the problem]

[0016] The subject of the present invention is a process for the hydrosilylation of an unsaturated compound (A) containing at least one monosubstituted alkene function with a compound (B) containing at least one hydrosilyl function, said process comprising a step consisting of irradiating said unsaturated compound (A) and said compound (B) in the presence of a photocatalyst (C) consisting of manganese carbonyl.

[0017] Another subject of the invention is the use of manganese carbonyl as a photocatalyst for the hydrosilylation reaction of an unsaturated compound (A) containing at least one monosubstituted alkene function with a compound (B) containing at least one hydrosilyl function. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Unless otherwise indicated, all viscosities of the silicone oils to which this description relates correspond to "Newtonian" kinematic viscosity quantities at 25° C., i.e. kinematic viscosities measured in a manner known per se using a Brookfield viscometer at shear rate gradients sufficiently low that the viscosity measured is independent of the rate gradient.

[0019] Although not depicted, possible tautomeric forms of the compounds described herein are included within the scope of the present invention.

[0020] In the present invention, the alkyl group may be linear or branched. The alkyl group preferably contains 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and even more preferably 1 to 6 carbon atoms. The alkyl group may be selected, for example, 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.

[0021] In the present invention, the cycloalkyl group can be monocyclic or polycyclic, preferably monocyclic or bicyclic. The cycloalkyl group preferably contains 3 to 30 carbon atoms, more preferably 3 to 8 carbon atoms. The cycloalkyl group can be selected, for example, from the following groups: cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, adamantyl and norbornyl.

[0022] In the present invention, the aryl group can be monocyclic or polycyclic, preferably monocyclic, and preferably contains 6 to 30 carbon atoms, more preferably 6 to 18 carbon atoms. The aryl group can be unsubstituted or substituted by one or more alkyl groups. The aryl group can be selected from phenyl, naphthyl, anthracenyl, phenanthryl, mesityl, tolyl, xylyl, diisopropylphenyl and triisopropylphenyl groups.

[0023] In the present invention, the arylalkyl group preferably contains 6 to 30 carbon atoms, more preferably 7 to 20 carbon atoms. The arylalkyl group can be chosen, for example, from the following groups: benzyl, phenylethyl, phenylpropyl, naphthylmethyl, naphthylethyl and naphthylpropyl.

[0024] In the present invention, the halogen atom can be, for example, selected from the group consisting of fluorine, bromine, chlorine and iodine, with fluorine being preferred. The fluorine-substituted alkyl group can be, for example, trifluoropropyl.

[0025] According to the definition given by IUPAC (Glossary of Terms Used in Photochemistry, 3rd edition; IUPAC Recommendations 2006), a photocatalyst is a catalyst that is able to bring about a chemical transformation in a reaction partner by absorbing light. The excited state of the photocatalyst interacts with the reaction partner to form a reaction intermediate, which itself is regenerated after each interaction cycle.

[0026] The present invention uses a photocatalyst (C) consisting of manganese carbonyl. Advantageously, manganese is an abundant natural element that is generally considered non-toxic within the range of doses that constitute a trace element. In the present invention, manganese carbonyl is a metal complex consisting of one or more manganese atoms and a carbonyl ligand bonded to the manganese. No other type of ligand is bonded to the manganese. Preferably, the manganese carbonyl is more specifically represented by the chemical formula [Mn2(CO) 10Advantageously, it is an inexpensive, air-stable, commercially available product.

[0027] The photocatalyst (C) according to the present invention does not use an organic ligand, in particular without the use of nitrogen-based ligands, e.g. pyridine ligands, and / or without the use of phosphorus-based ligands, e.g. phosphine ligands, and / or without the use of acyl-type ligands, and / or without the use of diketone ligands, e.g. β-diketone ligands, and / or without the use of substituted or unsubstituted cyclopentadienyl ligands, and / or -Without the use of organometallic ligands such as triphenylarsine can be advantageously employed.

[0028] Manganese in the metal complex is preferably in the oxidation state of 0. The metal complex does not contain any X-type ligands, in particular no halogen ligands.

[0029] The molar concentration of the photocatalyst (C) can be 0.01 mol% to 15 mol%, more preferably 0.05 mol% to 10 mol%, even more preferably 0.1 mol% to 5 mol%, and even more preferably 0.5 mol% to 2 mol% based on the total number of moles of unsaturation held by the unsaturated compound (A). According to another preferred embodiment, in the method according to the present invention, no compound based on platinum, palladium, ruthenium or rhodium is used. The amount of the compound based on platinum, palladium, ruthenium or rhodium in the reaction medium is, for example, less than 0.1 wt%, preferably less than 0.01 wt%, more preferably less than 0.001 wt%, based on the weight of the photocatalyst C.

[0030] The invention first comprises a method for hydrosilylation of an unsaturated compound (A) containing at least one monosubstituted alkene functional group with a compound (B) containing at least one hydrosilyl functional group, said method comprising a step consisting of irradiating said unsaturated compound (A) and said compound (B) in the presence of a photocatalyst (C) as described above.

[0031] The unsaturated compound (A) used in the hydrosilylation process of the present invention is a compound containing at least one monosubstituted alkene unsaturation that does not form part of an aromatic ring, which may be selected from those known to those skilled in the art and which do not contain reactive chemical functional groups that may interfere with or actually inhibit the hydrosilylation reaction.

[0032] As used herein, the term "monosubstituted alkene" or "monosubstituted alkenyl" is intended to mean a covalent double bond between two carbon atoms that are not part of an aromatic ring, and that are bonded to three hydrogen atoms and a monovalent group other than hydrogen atoms. The unsaturated compound (A) employed in the hydrosilylation process of the present invention can be represented by the following general formula (I): RCH=CH2(I) In the formula, R represents a monovalent group.

[0033] According to one embodiment, the unsaturated compound (A) comprises one or more monosubstituted alkene functional groups and 2 to 40 carbon atoms. The unsaturated compound (A) can be represented by the following general formula (I): RCH=CH2(I) In the formula, R represents a monovalent group selected from the group consisting of: alkyl groups having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and even more preferably 1 to 6 carbon atoms, which may be substituted by one or more halogen atoms, such as chlorine or fluorine, and by one or more groups selected from -OH and -OSiR'3 (each R' independently represents H or an alkyl group); aryl groups having 6 to 30 carbon atoms, more preferably 6 to 18 carbon atoms, optionally substituted by one or more halogen atoms, such as chlorine or fluorine, and optionally substituted by one or more groups selected from -OH and -OSiR'3, where each R', independently of one another, represents H or an alkyl group; Arylalkyl groups, preferably having 6 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, the aryl and / or alkyl moieties of which may be substituted by one or more halogen atoms, such as chlorine or fluorine, and by one or more groups selected from -OH and -OSiR'3, where each R', independently of the other, represents H or an alkyl group; an ether group of the formula -LOR″, in which L is a bond or a divalent group, preferably an alkylene group having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and R″ represents a group selected from the following groups: an alkyl group having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, even more preferably 1 to 6 carbon atoms, which may be substituted by one or more halogen atoms such as chlorine or fluorine, and which may be substituted by one or more groups selected from —OH and —OSiR′3 (each R′ independently represents H or an alkyl group); an alkyl group having 6 to 30 carbon atoms, more preferably 6 to 18 carbon atoms, aryl groups, which may be substituted by one or more halogen atoms, such as chlorine or fluorine, and may be substituted by one or more groups selected from -OH and -OSiR'3 (each R', independently of each other, represents H or an alkyl group); and arylalkyl groups, preferably having 6 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, whose aryl moiety and / or whose alkyl moiety may be substituted by one or more halogen atoms, such as chlorine or fluorine, and may be substituted by one or more groups selected from -OH and -OSiR'3 (each R', independently of each other, represents H or an alkyl group); An ester group of the formula -LOC(O)-R'', where L and R'' are as defined above.

[0034] The unsaturated compound (A) may preferably be an organic compound having 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 piperidinyl ether, preferably sterically hindered allyl piperidinyl ether, or allyl silyl ethers, preferably allyl trimethylsilyl ether, Allyl esters such as allyl acetate ·styrene, 1,2-epoxy-4-vinylcyclohexane, ·C1-C4 alkyl acrylates and acrylic acid.

[0035] The unsaturated compound (A) can be a disiloxane, such as vinylpentamethyldisiloxane, divinyltetramethyldisiloxane.

[0036] The unsaturated compound (A) can be selected from compounds containing several monosubstituted alkene functional groups, preferably two or three monosubstituted alkene functional groups, particularly preferably the compound (A) is selected from the following compounds: [ka]

[0037] According to a particularly preferred embodiment, the unsaturated compound (A) can be an organopolysiloxane compound containing one or more monosubstituted alkene functional groups, preferably at least two monosubstituted alkene functional groups. The hydrosilylation reaction of alkenes is one of the important reactions in silicone chemistry. It not only crosslinks the organopolysiloxanes having SiH functional groups with the organopolysiloxanes having alkenyl functional groups to form a network, imparting mechanical properties to the material, but also allows the organopolysiloxanes having SiH functional groups to be functionalized to modify their physical and chemical properties.

[0038] The organopolysiloxane compound is, in particular, at least two siloxyl units of the formula: Y a R 1 b SiO (4-a-b) / 2 (In the formula, Y is a monosubstituted C2-C 12 an alkenyl group, preferably a vinyl group; R 1 is a monovalent hydrocarbon group having 1 to 12 carbon atoms, preferably selected from an alkyl group having 1 to 8 carbon atoms, such as a methyl group, an ethyl group, or a propyl group, a cycloalkyl group having 3 to 8 carbon atoms, and an aryl group having 6 to 12 carbon atoms; a=1, 2 or 3, preferably a=1 or 2, more preferably a=1; b=0, 1 or 2; and the sum of a+b=1, 2 or 3; Optionally, the unit: R 1 c SiO (4-c) / 2 (In the formula, R 1 has the same meaning as above, and c=0, 1, 2 or 3. It consists of:

[0039] In the above formula, multiple R 1 It is understood that when a group is present or when multiple Y groups are present, they may be the same or different from one another. Preferentially, R1 R may represent a monovalent group selected from the group consisting of an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, and an aryl group having 6 to 12 carbon atoms, which may be substituted with at least one halogen atom such as chlorine or fluorine. 1 may advantageously be selected from the group consisting of methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl.

[0040] These organopolysiloxane compounds that contain one or more monosubstituted alkene functional groups can have a linear, cyclic or branched structure.

[0041] In the present invention Siloxyl unit "M Vi " is the formula YR 1 2SiO 1 / 2 or Y2R 1 SiO 1 / 2 represents a siloxyl unit, The siloxyl unit "M" is of the formula R 1 3SiO 1 / 2 represents a siloxyl unit, Siloxyl unit "D Vi " is the formula YR 1 SiO 2 / 2 represents a siloxyl unit, The siloxyl unit "D" is of the formula R 1 2SiO 2 / 2 represents a siloxyl unit, The siloxyl unit "T" is a compound of the formula R 1 SiO 3 / 2 represents a siloxyl unit, The siloxyl unit "Q" has the formula SiO 4 / 2 represents a siloxyl unit, Symbols Y and R 1 is as stated above.

[0042] Terminal "M" and "M ViExamples of the unit include a trimethylsiloxy group, a dimethylphenylsiloxy group, a dimethylvinylsiloxy group, and a dimethylhexenylsiloxy group.

[0043] "D" and "D Vi Examples of the unit include a dimethylsiloxy group, a methylphenylsiloxy group, a methylvinylsiloxy group, a methylbutenylsiloxy group, a methylhexenylsiloxy group, a methyldecenylsiloxy group, and a methyldecadienylsiloxy group.

[0044] Linear organopolysiloxane compounds containing one or more monosubstituted alkene functional groups are designated "D" and "D Vi " siloxyl units, "M" and "M Vi Examples of linear organopolysiloxanes which may be organopolysiloxane compounds containing one or more mono-substituted alkene functional groups according to the present invention are as follows: · Dimethylvinylsilyl terminated poly(dimethylsiloxane); · Dimethylvinylsilyl terminated poly(dimethylsiloxane-co-methylphenylsiloxane); Dimethylvinylsilyl-terminated poly(dimethylsiloxane-co-methylvinylsiloxane); and · Trimethylsilyl terminated poly(dimethylsiloxane-co-methylvinylsiloxane).

[0045] In a most preferred embodiment, the organopolysiloxane compound containing one or more mono-substituted alkene functional groups contains terminal dimethylvinylsilyl units. More preferably, the organopolysiloxane compound containing one or more mono-substituted alkene functional groups is a dimethylvinylsilyl-terminated poly(dimethylsiloxane).

[0046] The viscosity of the silicone oil is generally 1 mPa.s to 2,000,000 mPa.s. Preferably, the organopolysiloxane compound containing one or more alkene functional groups is a silicone oil having a dynamic viscosity of 20 mPa.s to 100,000 mPa.s at 25°C, preferably 20 mPa.s to 80,000 mPa.s at 25°C, more preferably 100 mPa.s to 50,000 mPa.s.

[0047] The cyclic organopolysiloxane compounds containing one or more monosubstituted alkene functional groups are described above as "D" and "D Vi " consisting essentially of siloxyl units. An example of a cyclic organopolysiloxane which may be the organopolysiloxane compound containing one or more mono-substituted alkene functional groups according to the present invention is cyclic poly(methylvinylsiloxane).

[0048] Optionally, the organopolysiloxane compound containing one or more mono-substituted alkene functional groups can further contain "T" siloxyl units and / or "Q" siloxyl units, and the organopolysiloxane compound containing one or more mono-substituted alkene functional groups has a branched structure.

[0049] Examples of branched organopolysiloxanes, also called resins, which are organopolysiloxane compounds containing one or more mono-substituted alkene functional groups according to the present invention are as follows: ·MD Vi Q, where the vinyl group is contained in the D unit; ·MD Vi TQ, where the vinyl group is contained in the D unit; ·MM Vi Q, where the vinyl group is included as part of the M unit; ·MM Vi TQ, where the vinyl group is part of the M unit, ·MM Vi DD Vi Q, where the vinyl group is contained as part of the M unit and the D unit; · and mixtures thereof.

[0050] Preferably, the organopolysiloxane compound containing one or more mono-substituted alkene functional groups has a content of mono-substituted alkenyl units of 0.001% to 30% by weight, preferably 0.01% to 10% by weight, more preferably 0.02% to 5% by weight.

[0051] An unsaturated compound (A) is reacted according to the invention with a compound (B) containing at least one hydrosilyl functional group.

[0052] According to one embodiment, the compound (B) containing at least one hydrosilyl functional group is a silane or polysilane compound containing at least one hydrogen atom bonded to a silicon atom. By "silane" compound, it is meant in the present invention a compound containing a silicon atom bonded to four hydrogen atoms or organic substituents. By "polysilane" compound, it is meant in the present invention a compound having at least one ≡Si-Si≡ unit. Among the silane compounds, the compound (B) containing at least one hydrosilyl functional group can be phenylsilane or a mono-, di- or trialkylsilane, for example triethylsilane.

[0053] According to another embodiment, the compound (B) containing at least one hydrosilyl functional group is an organopolysiloxane compound containing at least one hydrogen atom bonded to a silicon atom, also called organohydropolysiloxane. The organohydropolysiloxane is advantageously at least two siloxyl units of the formula: H d R 1 e SiO (4-d-e) / 2 (In the formula, R 1 is a monovalent hydrocarbon group having 1 to 12 carbon atoms, preferably selected from an alkyl group having 1 to 8 carbon atoms, such as a methyl group, an ethyl group, or a propyl group, a cycloalkyl group having 3 to 8 carbon atoms, and an aryl group having 6 to 12 carbon atoms; 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; Optionally, the unit: R 1 f SiO (4-f) / 2 (In the formula, R 1 has the same meaning as above, and f=0, 1, 2 or 3. The organopolysiloxane may be composed of

[0054] In the above formula, some R 1 When groups are present, they may be identical or different from one another. Preferentially, R 1 R may represent a monovalent group selected from the group consisting of an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, and an aryl group having 6 to 12 carbon atoms, which may be substituted with at least one halogen atom such as chlorine or fluorine. 1 may advantageously be selected from the group consisting of methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl.

[0055] The organohydropolysiloxane may have a linear, branched or cyclic structure. The degree of polymerization is preferably 2 or more and generally 5000 or less.

[0056] In the following, the "M", "D", "T" and "Q" siloxyl units are as defined above, and "M'" siloxyl units have the formula HR 1 2SiO 1 / 2 represents a siloxyl unit, "D'" siloxyl units have the formula HR 1 SiO 2 / 2 represents a siloxyl unit, Symbol R 1 is as stated above.

[0057] Where linear polymers are concerned, these consist essentially of siloxyl units selected from the formula "D" and "D'" siloxyl units and "M" and "M'" terminal siloxyl units.

[0058] Examples of organohydropolysiloxanes which can be compounds (B) containing at least one hydrosilyl functional group according to the invention are: · Hydrodimethylsilyl terminated poly(dimethylsiloxane); · Trimethylsilyl terminated poly(dimethylsiloxane-co-methylhydrosiloxane); · hydrodimethylsilyl-terminated poly(dimethylsiloxane-co-methylhydrosiloxane); and · Trimethylsilyl terminated poly(methylhydrosiloxane).

[0059] When the organohydrogenpolysiloxane has a cyclic structure, it consists essentially of siloxyl units selected from "D" and "D'" siloxyl units. An example of a cyclic organohydrogenpolysiloxane which can be the compound (B) containing at least one hydrosilyl functional group according to the present invention is cyclic poly(methylhydrogensiloxane).

[0060] When the organohydropolysiloxane has a branched structure, it is preferably selected from the group consisting of silicone resins of the following formula: M'Q, where the hydrogen atom bonded to the silicon atom is held by the M group, MM'Q, where the hydrogen atom bonded to the silicon atom is carried by part of the M unit, MD'Q, where the hydrogen atom bonded to the silicon atom is held by a D group, MDD'Q, where the hydrogen atom bonded to the silicon atom is held by part of the D group, MM'TQ, where the hydrogen atom bonded to the silicon atom is carried by part of the M unit, MM'DD'Q, where the hydrogen atoms bonded to the silicon atoms are carried by the M units and by part of the D units, · and mixtures thereof.

[0061] Preferably, the organohydropolysiloxane compound has a hydrosilyl Si-H functional group content of 0.2% to 91% by weight, more preferably 3% to 80% by weight, and even more preferably 15% to 70% by weight.

[0062] According to a particular embodiment of the present invention, the unsaturated compound (A) and the compound (B) containing at least one hydrosilyl functional group can be one and the same compound, which on the one hand contains at least one monosubstituted alkene functional group, and on the other hand contains at least one silicon atom and at least one hydrogen atom bonded to the silicon atom. This compound can be described as "bifunctional" and can react by itself by hydrosilylation reaction. Thus, the present invention can also relate to a method for hydrosilylation of a bifunctional compound itself, which bifunctional compound contains on the one hand at least one monofunctional alkene functional group, and on the other hand contains at least one silicon atom and at least one hydrogen atom bonded to the silicon atom, and said method is catalyzed by a photocatalyst (C) as described above.

[0063] Examples of organopolysiloxanes which can be difunctional compounds are: Dimethylvinylsilyl-terminated poly(dimethylsiloxane-co-hydromethylsiloxane-co-vinylmethylsiloxane), Dimethylhydrosilyl-terminated poly(dimethylsiloxane-co-hydromethylsiloxane-co-vinylmethylsiloxane); and · Trimethylsilyl terminated poly(dimethylsiloxane-co-hydromethylsiloxane-co-(propylglycidyl ether)methylsiloxane).

[0064] When referring to the use of an unsaturated compound (A) and a compound (B) containing at least one hydrosilyl function, the skilled person will understand that this also means the use of a difunctional compound.

[0065] The amounts of compound (A) and compound (B) can be controlled so that the molar ratio of the mono-substituted alkene functional group of compound (A) to the hydrosilyl functional group of compound (B) is preferably 1:10 to 10:1, more preferably 1:5 to 5:1, even more preferably 1:3 to 3:1, and even more preferably 1:2 to 2:1.

[0066] The method according to the invention comprises the step of irradiating said unsaturated compound (A) and said compound (B) in the presence of a photocatalyst (C).

[0067] The irradiation is preferably exposure to ultraviolet light and / or visible light. In this specification, "UV" means ultraviolet light. Ultraviolet light is defined as electromagnetic radiation having a wavelength between about 100 nm and about 400 nm, i.e., below the spectrum of visible light. Among ultraviolet light, UV-A radiation having a wavelength between about 315 nm and about 400 nm, UV-B radiation having a wavelength between about 280 nm and about 315 nm, and UV-C radiation having a wavelength between about 100 nm and about 280 nm can be defined. Visible light is defined as electromagnetic radiation having a wavelength between about 400 nm and about 800 nm. Preferably, the irradiation is carried out by exposure to radiation having a wavelength between 100 nm and 450 nm, or between 200 nm and 420 nm, or between 250 nm and 405 nm.

[0068] The radiation is emitted from a doped or undoped mercury lamp, the emission spectrum of which ranges from 100 nm to 450 nm. Light sources such as LEDs that emit UV or visible light can also be employed. Furthermore, in this specification, "LED" is an abbreviation for "light emitting diode," which is well known to those skilled in the art.

[0069] According to one embodiment, the irradiation is performed with UV radiation, the source of which is a UV-LED lamp. This UV-LED lamp can emit radiation with wavelengths of 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 2 W / m 2 ~200,000W / m2 It is between.

[0070] According to a preferred embodiment, the irradiation step is carried out under an inert atmosphere, for example under nitrogen, argon or oxygen-depleted air.

[0071] 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, more preferably even at ambient temperature, ie typically around 25°C.

[0072] The hydrosilylation reaction can be carried out in a solvent or in the absence of a solvent. Suitable solvents are those that are miscible with compound (B). For example, the solvent can be selected from the group consisting of aliphatic hydrocarbons such as pentane, hexane, heptane, cyclohexane, decalin and liquid paraffin; 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 glycol; and mixtures thereof. Preferably, the solvent can be selected from the group consisting of aliphatic hydrocarbons, aromatic hydrocarbons and chlorinated hydrocarbons, more preferably from the group consisting of hexane, cyclohexane, decalin and toluene. In another embodiment, the solvent can be selected from volatile silicones, octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), polydimethylsiloxane oil (PDMS), polyphenylmethylsiloxane oil (PPMS) or mixtures thereof. In another embodiment, one of the reactants, for example the unsaturated compound (A), can act as the solvent. Preferably, the use of organic solvents, which are harmful to the environment and the health of workers in the manufacturing plant, is avoided.

[0073] According to a preferred embodiment of the invention, the compounds (A) and (B) employed are selected from organopolysiloxanes as defined above. In this case, a three-dimensional network is formed, which results in the composition being cured. Crosslinking is accompanied by a gradual physical change of the medium constituting the composition. As a result, elastomers, gels, foams, etc. can be obtained using the method according to the invention. In this case, a crosslinked silicone material is obtained. The term "crosslinked silicone material" is intended to mean any silicone-based product obtained by crosslinking and / or curing a composition comprising an organopolysiloxane having at least two unsaturated bonds and an organopolysiloxane having at least three hydrosilyl units. The crosslinked silicone material can be, for example, an elastomer, a gel or a foam.

[0074] According to this preferred embodiment of the process according to the invention, in which the compounds (A) and (B) are selected from organopolysiloxanes as defined above, it is possible to use in the silicone composition conventional functional additives. Conventional functional additives include: Fillers, Adhesion promoters, Inhibitors or retarders of hydrosilylation reactions, Adhesion regulators, Silicone resin, -Consistency improver, Pigments (organic or inorganic), Heat-resistant additives, oil-resistant additives, fire-resistant additives, such as metal oxides.

[0075] The optionally provided filler is preferably inorganic. The filler may be a very finely divided product with an average particle size of less than 0.1 μm. The filler may in particular be siliceous. As regards siliceous materials, they may act as reinforcing or semi-reinforcing fillers. The reinforcing siliceous fillers are selected from colloidal silica, fumed silica powder, precipitated silica powder, or mixtures thereof. These powders generally have an average particle size of less than 0.1 μm (micrometer) and a particle size of less than 30 μm. 2 / g, preferably 30 to 350 m 2 / g. Semi-reinforcing siliceous fillers such as diatomaceous earth and crushed quartz can also be used. These silicas can be incorporated as is or after treatment with organosilicon compounds commonly used for this application. These compounds include methylpolysiloxanes such as hexamethyldisiloxane or octamethylcyclotetrasiloxane, methylpolysilazanes such as hexamethyldisilazane, hexamethylcyclotrisilazane or tetramethyldivinyldisilazane, chlorosilanes such as dimethyldichlorosilane, trimethylchlorosilane, methylvinyldichlorosilane or dimethylvinylchlorosilane, alkoxysilanes such as dimethyldimethoxysilane, dimethylvinylethoxysilane or trimethylmethoxysilane, and mixtures thereof. As for the non-siliceous inorganic materials, they can participate as semi-reinforcing or extending inorganic fillers. Examples of these non-siliceous fillers, which can be used alone or in mixtures, are calcium carbonate, which may be surface-treated with organic acids or esters of organic acids, calcined clays, titanium oxide in the rutile form, oxides of iron, zinc, chromium, zirconium or magnesium, various forms of alumina (hydrated or non-hydrated), boron nitride, lithopone, barium metaborate, barium sulfate and glass microbeads. These fillers generally have an average particle size of more than 0.1 μm and a specific surface area of ​​generally 30 m 2 / g. These fillers may be surface modified by treatment with various organosilicon compounds commonly used for this application. Preferably, the filler is silica, more preferably fumed silica. Advantageously, the silica has a particle size of 75 to 410 m 2 / g. The silicone composition may contain between 5% and 20% by weight of filler relative to the total weight of the silicone composition. Advantageously, the silicone composition may contain between 8% and 15% by weight of filler.

[0076] The discovery of the novel photocatalytic hydrosilylation method under mild conditions according to the present invention allows for many applications to be envisaged.

[0077] According to a first embodiment, the hydrosilylation method according to the present invention can be used for the functionalization of organopolysiloxanes having SiH functional groups. The purpose of functionalization is to modify the physical and / or chemical properties of said organopolysiloxanes to produce novel compounds with improved properties. According to this embodiment, the unsaturated compound (A) containing at least one monosubstituted alkene functional group is selected from unsaturated compounds containing one or more monosubstituted alkene functional groups and 2 to 40 carbon atoms, and the compound (B) containing at least one hydrosilyl functional group is an organopolysiloxane compound containing at least one hydrogen atom bonded to a silicon atom. A method for functionalizing organopolysiloxanes having SiH functional groups can be described, characterized in that the addition reaction between organopolysiloxanes having SiH functional groups and unsaturated compounds (A) containing one or more monosubstituted alkene functional groups and 2 to 40 carbon atoms is obtained by the hydrosilylation method as described above.

[0078] According to another particularly preferred embodiment, the hydrosilylation method according to the invention can be used for crosslinking organopolysiloxanes having SiH functional groups with organopolysiloxanes having alkenyl functional groups to form a network and to impart mechanical properties to the material. According to this embodiment, the unsaturated compound (A) containing at least one monosubstituted alkene functional group is an organopolysiloxane compound containing at least two monosubstituted alkene functional groups, and the compound (B) containing at least one hydrosilyl functional group is an organopolysiloxane compound containing at least three hydrogen atoms bonded to silicon atoms. A method for producing a crosslinked silicone material can be described, characterized in that the crosslinking reaction between an organopolysiloxane having SiH functional groups and an organopolysiloxane having alkenyl functional groups is obtained by a hydrosilylation method as described above. The crosslinked silicone material thus obtained can be used in various applications, in particular: Coating type applications in which the substrate is coated with a silicone coating; Applications in the electronics sector, e.g. production of conformal coatings on printed circuits, potting of microcircuits and electronic components such as IGBTs; · Additive manufacturing processes using photopolymerization (also known as 3D printing processes).

[0079] Other details or advantages of the invention will become more clearly apparent in the light of the examples given below, which are given purely by way of illustration. EXAMPLES

[0080] Examples 1 to 3 and Comparative Examples 1 to 3: Hydrosilylation of 1-octene (1) with 1,1,1,3,5,5,5-heptamethyltrisiloxane (2) [ka]

[0081] 1-Octene (1) and 1,1,1,3,5,5,5-heptamethyltrisiloxane (2) were placed in a 4 mL vial at ambient temperature under an argon atmosphere. 10 The toluene solution was poured into a vial and toluene was added. 10 The final concentration (relative to 1-octene) was 1 mol %.

[0082] In Examples 1, 2 and 3, the reaction mixture was placed under UV light (300 W, λ=250-420 nm) for 4 hours. In Comparative Examples 1, 2 and 3, the reaction mixture was not irradiated and was heated for 24 hours. The reactant concentrations and reaction conditions are as shown in Table 1, as are the yields of hydrosilylation product (3) and isomerization product of (1) (determined by gas chromatography, calculated relative to 1-octene).

[0083] [Table 1]

[0084] Examples 1, 2 and 3 are Mn2(CO) 10It has been shown that the hydrosilylation reaction of 1-octene (1) with 1,1,1,3,5,5,5-heptamethyltrisiloxane (2) photocatalyzed by 1H2O2 can give the product (3) in good yield and selectivity under mild reaction conditions (ambient temperature for 4 hours). Conversely, this catalyst is not active upon thermal activation (Comparative Examples 1, 2, 3).

[0085] Examples 4-12 and Comparative Examples 4-6: Hydrosilylation of Various Alkenes (1') [ka]

[0086] The same procedure as described in Example 1 (UV, 4 hours) was followed while varying the structure of the alkene compound (1') as shown in Table 2 below. The yields of the hydrosilylated products (3') (determined by gas chromatography, calculated relative to the alkene) are shown in Table 2.

[0087] [Table 2]

[0088] In Examples 4 to 12, hydrosilylation products were obtained with excellent selectivity. Neither C=C isomerization nor products due to C-O bond cleavage were observed. On the other hand, no hydrosilylation products were obtained starting from gem-disubstituted alkenes (Comparative Examples 4 and 5) or from internal alkenes (Comparative Example 6).

Claims

1. A process for hydrosilylation of an unsaturated compound (A) containing at least one monosubstituted alkene functional group with a compound (B) containing at least one hydrosilyl functional group, said process comprising the step of irradiating said unsaturated compound (A) and said compound (B) in the presence of a photocatalyst (C) consisting of manganese carbonyl.

2. 2. The hydrosilylation process of claim 1, wherein the manganese in the manganese carbonyl is in an oxidation state of 0.

3. The manganese carbonyl has the chemical formula [Mn 2 (CO) 10 3. The hydrosilylation method according to claim 1 or 2, wherein the dimanganese decacarbonyl is of the formula:

4. The hydrosilylation method according to any one of claims 1 to 3, characterized in that the unsaturated compound (A) is an organic compound having 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 C 1 ~C 8 an alkyl ether, an allyl glycidyl ether, an allyl piperidinyl ether, preferably a sterically hindered allyl piperidinyl ether, or an allyl silyl ether, preferably an allyl trimethylsilyl ether; Allyl esters such as allyl acetate, ·styrene, 1,2-epoxy-4-vinylcyclohexane, Acrylic acid C 1 ~C 4 Alkyl and acrylic acids.

5. 4. The hydrosilylation process according to claim 1, wherein the unsaturated compound (A) is an organopolysiloxane compound containing one or more monosubstituted alkene functional groups, preferably at least two monosubstituted alkene functional groups.

6. 6. The hydrosilylation method according to claim 1, wherein the compound (B) containing at least one hydrosilyl functional group is an organopolysiloxane compound containing at least one hydrogen atom bonded to a silicon atom.

7. 7. A hydrosilylation process according to any of claims 1 to 6, characterized in that the irradiation is carried out by exposure to radiation of wavelengths between 100 nm and 450 nm, or between 200 nm and 420 nm, or between 250 nm and 405 nm.

8. The hydrosilylation process according to any one of claims 1 to 7, characterized in that the irradiation is carried out with UV irradiation using a UV-LED lamp as a light source.

9. 9. A hydrosilylation process according to any of claims 1 to 8, 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, even more preferably at ambient temperature.

10. 10. A hydrosilylation process for the functionalization of organopolysiloxanes bearing SiH functional groups according to claims 1, 2, 3, 7, 8 or 9, characterized in that the unsaturated compound (A) containing at least one monosubstituted alkene functional group is selected from unsaturated compounds containing one or more monosubstituted alkene functional groups and 2 to 40 carbon atoms, and the compound (B) containing at least one hydrosilyl functional group is an organopolysiloxane compound containing at least one hydrogen atom bonded to a silicon atom.

11. 10. A hydrosilylation process according to claim 1, 2, 3, 7, 8 or 9 for the preparation of a crosslinked silicone material, characterized in that the unsaturated compound (A) containing at least one monosubstituted alkene functional group is an organopolysiloxane compound containing at least two monosubstituted alkene functional groups, and the compound (B) containing at least one hydrosilyl functional group is an organopolysiloxane compound containing at least three hydrogen atoms bonded to silicon atoms.

12. Use of manganese carbonyl as a photocatalyst for the hydrosilylation reaction of an unsaturated compound (A) containing at least one monosubstituted alkene functional group with a compound (B) containing at least one hydrosilyl functional group.

13. 13. Use according to claim 12, characterised in that the manganese in the manganese carbonyl is in the oxidation state of 0.

14. The manganese carbonyl has the chemical formula [Mn 2 (CO) 10 14. The method according to claim 12 or 13, characterized in that the compound is dimanganese decacarbonyl of the formula:

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