Method of preparing halogenoalkyldialkyl chlorosilane

A method for the preparation of a haloalkyldialkylhalosilane of formula (I):

• Hal-(R2R3)Si—(CH2)s-Hal (I)
• by hydrosilylation reaction of a reaction medium comprising:
• a silane of formula (II):
• Hal-(R2R3)Si—H (II)
• and an alkenyl halide of formula (III):
• CH═CH—(CH2)s-2Hal (III)
• in the presence of a catalytically effective amount of a hydrosilylation catalyst based on iridium in the oxidation state I or III,
• in which formulae (I), (II), (III):
• the symbol Hal represents a halogen atom selected from the group consisting of chlorine, bromine and iodine atoms,
• the symbols R2 et R3, which may be identical or different, are each a monovalent hydrocarbon radical selected from the group consisting of a linear or branched alkyl radical having from 1 to 6 carbon atoms and a phenyl radical, and
• s is an integer ranging from 2 to 10 inclusive, and wherein
• said method at least one auxiliary in the free or supported state selected from the group of compounds consisting of:
• (i) ketones,
• (ii) ethers,
• (iii) quinones,
• (iv) anhydrides,
• (v) unsaturated hydrocarbon compounds (UHC) whether aromatic and/or comprising at least one C═C double bond and/or at least one C≡C triple bond, it being possible for these unsaturated bonds to be conjugated or nonconjugated, the said UHCs being linear or cyclic (mono- or polycyclic), having from 4 to 30 carbon atoms, having from 1 to 8 ethylenic and/or acetylenic sites of unsaturation and optionally comprising one or more heteroatoms, and
• (vi) mixtures thereof,
• is added to the reaction medium, with the proviso that, when the auxiliary comprises one or more UHCs as defined above, then this (these) UHC(s) is (are) mixed with at least one other auxiliary other than a UHC.

A catalytic system for the preparation of a haloalkyldialkylhalosilane of formula (I):

• Hal-(R2R3)Si—(CH2)s-Hal (I)
• by hydrosilylation reaction of a reaction medium comprising:
• a silane of formula (II):
• Hal-(R2R3)Si—H (II)
• and an alkenyl halide of formula (III):
• CH═CH—(CH2)s-2Hal (III)
• in which formulae:
• the symbol Hal represents a halogen atom selected from the group consisting of chlorine, bromine and iodine atoms,
• the symbols R2 et R3, which may be identical or different, are each a monovalent hydrocarbon radical selected from the group consisting of a linear or branched alkyl radical having from 1 to 6 carbon atoms and a phenyl radical, and
• s is an integer ranging from 2 to 10 inclusive, and which comprises:
• (1) a hydrosilylation catalyst based on iridium in the oxidation state I, in the structure of which each iridium atom corresponds to the complex form of the Ir(L)3X type wherein the symbols L and X have the definitions given in the text “Chimie Organométallique” [Organometallic Chemistry] by Didier Astruc, published in 2000 by EDP Sciences, or having the formula:
• [Ir(R4)x(R5)]y (IV)
• in which:
• the symbol R4 represents either a monodentate ligand L, and in this case x=2, or a bidentate ligand (L)2 and in this case x=1, and
• the symbol R5 represents either Hal, Hal representing a halogen atom selected from the group consisting of chlorine, bromine and iodine atoms, and in this case y=2, or a ligand of type LX, and in this case y=1, and
• (2) at least one auxiliary in the free or supported state selected from the group of compounds consisting of:
• (i) ketones,
• (ii) ethers,
• (iii) quinones,
• (iv) anhydrides,
• (v) unsaturated hydrocarbon compounds (UHC) whether aromatic and/or comprising at least one C═C double bond and/or at least one C≡C triple bond, it being possible for these unsaturated bonds to be conjugated or nonconjugated, the said UHCs being linear or cyclic (mono- or polycyclic), having from 4 to 30 carbon atoms, having from 1 to 8 ethylenic and/or acetylenic sites of unsaturation and optionally comprising one or more heteroatoms, and
• (vi) mixtures thereof,
• with the proviso that, when the auxiliary comprises one or more UHCs as defined above, then this (these) UHC(s) is (are) mixed with at least one other auxiliary other than a UHC.