EP2049553A1

EP2049553A1 - Method for production of organosilicon compounds by hydrosilylation in ionic liquids

Info

Publication number: EP2049553A1
Application number: EP07765548A
Authority: EP
Inventors: Andreas Bauer; Thomas Frey; Peter Wasserscheid; Peter Schulz; Norbert Hofmann
Original assignee: Wacker Chemie AG
Current assignee: Wacker Chemie AG
Priority date: 2006-06-27
Filing date: 2007-06-21
Publication date: 2009-04-22
Also published as: CN101472932A; JP2009541420A; US20100267979A1; WO2008000689A1; DE102006029430A1

Abstract

The invention relates to a method for production of silanes by hydrosilylation, characterised in that a transition metal complex is used as catalyst for the hydrosilylation reaction, which is present in solution in an ionic liquid during the reaction.

Description

Process for the preparation of organosilicon compounds by hydrosilylation in ionic liquids

The invention relates to a process for the preparation of organosilicon compounds by hydrosilylation in ionic liquids.

The preparation of organosilicon compounds is carried out according to the prior art after the Muller-Rochow synthesis. The functionalized organosilanes are of great economic importance, in particular halogen-substituted ones, since they serve as starting materials for the preparation of many important products, for example silicones, adhesion promoters, water repellents and building protection agents.

However, this direct synthesis is not equally well suited for all silanes. The production of so-called manganese silanes is difficult in this way and possible only with poor yields.

One way to prepare manganese silanes is to convert easily prepared silanes (excess silanes) to manganese silanes by a ligand exchange reaction. The use of ionic liquids in the two-phase system for ligand exchange of organochlorosilanes with other organochlorosilanes and is described for example in the patent DE 101 57 198 Al. In this process, a ligand exchange reaction takes place on the silicon atom, in which an organosilane in the presence of an ionic liquid, which is a halide,

Metal or transition metal halide of organic nitrogen or phosphorus compounds, disproportionated or with another organosilane is reacted under ligand exchange.

Ionic liquids are generally understood to mean salts or mixtures of salts whose melting points are below 100 ^° C., as described, for example, in P. Wasserscheid, W. Keim, Angew. Chem. 2000, 112, 3926. Literature-known salts of this type consist of anions such as halogenostannates, halogenoaluminates, hexafluorophosphates, tetrafluoroborates, alkyl sulfates, alkyl or aryl sulfonates, dialkyl phosphates, rhodanides or dicyanamides combined with substituted ammonium, phosphonium, imidazolium, pyridinium, pyrazolium, triazolium, picolinium - or pyrrolidinium cations. Numerous publications already describe the use of ionic liquids as solvents for

Transition metal catalyzed reactions such as T. Welton, Chem. Rev. 1999, 99, 2071, and P. Wasserscheid, W. Keim, Angew. Chem., 2000, 112, 3926, and P. Wasserscheid, T. Welton (Eds.) &Quot; Ionic Liquids in Synthesis ", 2003, Wiley-VCH, Weinheim, pp 213-257 These publications and the papers cited therein describe Part noteworthy improvements in the catalyst properties of transition-metal catalysts when used in the catalytic reactions instead of solubilized in organic solvents in ionic liquids

Improvements are also of considerable technical relevance and occur, for example, in a significantly improved catalyst removability and catalyst reuse, a significantly increased catalyst stability, a significantly increased reactivity or a significantly improved

Selectivity of the catalyzed reaction to light. In general, ionic liquids offer the possibility of a gradual coordination of relevant structural variations Solvent properties towards a specific application goal.

The hydrosilylation of 1-alkenes is known to be catalyzed by platinum group metal complexes as described, for example, in J. Marciniec, "Comprehensive Handbook on Hydrosilylation", Pergamon Press, New York 1992. Especially platinum complexes such as the so-called "Speier catalyst" [H ₂ PtCl ₆ * 6 H ₂ O] and the "Karstedt solution", a complex compound of [H ₂ PtCl ₆ * 6 H ₂ O] and vinyl-substituted disiloxanes, are known to be very active catalysts in that with the use of some anhydrous platinum compounds, for example dicycloocadienylplatinum ([Pt (cod) ₂ ]), platinum colloids are formed, which are also highly active hydrosilylation catalysts as described, for example, in LN Lewis, N. Lewis, J. Am. Chem Soc., 1986, 108, 7728.

Performing the hydrosilylation reaction as a liquid-liquid two-phase reaction requires a system with a polar and a nonpolar solvent in which both solvents have a miscibility gap. The systems cyclohexane / propene were published as nonpolar and cyclohexane / propylene carbonate as the polar phase in A. Behr, N. Toslu, Chem. Eng. Technol. 2000, 23, 2. With this system, for example, the hydrosilylation of Ω-undecenoic acid with triethoxysilane, where the product is enriched in the non-polar phase and can be easily separated from the catalyst and the starting materials which remain in the polar phase. Nevertheless, the separation succeeds in this particular case only because of the very nonpolar nature of the unsaturated fatty acid used. The use of ionic liquids as the catalyst phase in the Pt-catalyzed hydrosilylation of terminal olefins with SiH-functionalized polydimethylsiloxanes is also known, for example, in B. Weyershausen, K. Hell, U. Hesse, Green. Chem., 2005, 7, 283. Accordingly, the use of ionic liquids as the polar phase leads to a segregation of the catalyst phase and the non-polar products, so that the products themselves form the second non-polar phase. Separation of the products from the polar IL / catalyst / educt phase is thus possible without further work-up by distillation. For the specific case of hydrosilylation of terminal olefins with SiH-functionalized polydimethylsiloxanes it has been shown that the conditions for a technical use of the liquid-liquid two-phase reaction, namely the complete solubility of the Pt catalyst in the ionic liquid and the mixing gap between ionic liquid and the products can be ensured by targeted design of the anions and cations of the ionic liquid. The hydrosilylation with SiH-functionalized polydimethylsiloxanes here is not limited only to terminal olefins, but can, as disclosed in the patent EP 1 382 630 Al, be extended to all compounds containing CC multiple bond.

As a novel concept of efficiently carrying out transition-metal-catalyzed reactions in ionic liquids, the so-called "supported ionic liquid phase" (= SILP) catalyst technology has been established for a few years, starting with Mehnert's example of Rh-catalyzed hydroformylation and hydrogenation reactions in C. P. Mehnert, RA Cook, NC Dispenziere, M. Afeworki, J. Am. Chem Soc, 2002, 124 12932-12933, and CP Mehnert, EJ Mozeleski, RA Cook, Chem. Commun. 2002, 3010-3011. In SILP catalyst technology, the solution of a transition metal complex in an ionic liquid is applied to a mostly highly porous carrier, by physisorption or chemical reaction, and the resulting solid catalyst is contacted with the reactants in a gas phase or liquid phase reaction. This technology represents a new approach to combining the advantages of classical homogeneous catalysis with those of classical heterogeneous catalysis. By drawing a few nanometers thick film of ionic

Catalyst solution on a porous solid, it is achieved that without high input of mechanical energy to the reactants a high specific surface of ionic catalyst solution is ready for reaction. The catalyst is still homogeneous dissolved here. The technology also provides very easy access to continuous processes, for example, in A. Riisager, P. Wasserscheid, R. van HaI, R. Fehrmann, J. Catal. 2003, 219, 252. As the font A. Riisager, R. Fehrmann, S. Flicker, R. van HaI, M. Haumann, P. Wasserscheid, Angew. Chem., Int. Ed. 2005, 44, 815-819 shows in spectroscopic and kinetic studies at least for the Rh-catalyzed hydroformylation, while the transition metal catalyst is still present in dissolved form in the immobilized Flussigfilm. Due to possible

Interactions of the active surface groups of the porous support with the transition metal catalyst in only a few nanometers thick carrier film, the successful use of SILP technology for the skilled person not obvious. Other known applications of SILP technology include

Carrying out the Pd-catalyzed Heck reaction and Rh, Pd, or Zn-catalyzed hydroamination using supported ionic catalyst solutions. this will for example in H. Hagiwara, Y. Sugawara, K. Isobe, T. Hoshi,

T. Suzuki, Org. Lett. 2004, 6, 2325 and S. Breitenlechner, M.

Fleck, T.E. Muller, A. Suppan, J. Mol. Catal. A: Chem. 2004, 214, 175.

In the patent WO 02/098560 Al Mehnert discloses the

Preparation of SILP Catalysts by Reaction of a Reactive Side Chain Ionic Liquid with a Silicate Support. In connection with the representation of the ionic liquid with a reactive side chain, the hydrosilylation is mentioned here as a method. The disclosed reaction is a method of introducing the reactive side chain into ionic liquids which are to be bonded to silicate carriers by formation of a covalent bond.

The object of the invention was therefore to provide a process for the preparation of silanes by hydrosilylation, which proceeds very selectively and thus leads to high yields of the desired silanes.

This object has been achieved by the process according to the invention for the preparation of silanes by hydrosilylation, which is characterized in that the catalyst used for the hydrosilylation reaction is a transition metal complex compound which is dissolved in an ionic liquid during the reaction.

An advantage of the novel process according to this invention is the technical possibility of catalyst separation and recirculation in the liquid-liquid multiphase system or in variants in which the ionic catalyst solution is applied to solids. In addition, in many cases compared to the known synthesis method a achieved significant selectivity improvement in silane synthesis.

In the process according to the invention, in the hydrosilylation, non-polymeric compounds of the general formula (1)

H _a SiR _b (1),

with alkenes of the general formula 2

R ⁸ R ⁹ C = CR ¹⁰ R ¹¹ (2:

converted, where R is independently a H, a monovalent Si-C-bonded, optionally halogen-substituted _C] _{_-C]} _g-

Hydrocarbon, chlorine, or C] _ C] _g alkoxy, a 1,2 or 3, b 4-a, R ⁸ , R ⁹ , R ¹⁰ and R ^{11 are} independently H, a monovalent optionally with F , Cl, OR, NR 2, CN or NCO substituted C] _C] _g hydrocarbon, chlorine, fluorine or C] _- C] _g alkoxy radical, wherein in each case 2 radicals of R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ together with the carbon atoms to which they are attached can form a cyclic radical. In the process according to the invention, those of the general formula (3) are preferably reacted as non-polymeric compounds

R _c H _d S ICl ₄ -C-Ci (3),

in which

R carries the meaning given above, and c the values 0, 1, 2, 3 or 4 and d can have the values 1, 2 or 3.

That this reaction succeeds was very surprising. According to the document DE 101 57 198 Al, this would not have been expected, since in the presence of an ionic liquid, which is a halide, metal or transition metal halide of organic nitrogen or phosphorus compounds, the selectivity of such a hydrosilylation reaction by the parallel to expected disproportionation of the silane or by the parallel expected ligand exchange of two organosilanes should not lead in sufficiently high selectivity to the desired product of hydrosilylation. Such a superposition of hydrosilylation, disportportionation, and ligand exchange reaction should thus technically facilitate the preparative use of hydrosilylation of non-polymeric compounds bearing one or more H-Si functionality (s) with unsaturated compounds using ionic catalyst solutions in the liquid-liquid multiphase system to make something useless.

The inventive reaction of compounds according to the

Formula (1), which carry one or more H-Si functionality (s), is preferably carried out with such alkenes, in addition to Carbon and hydrogen may still contain chlorine, alkoxy or amino functionalities.

In addition, there is the additional problem in the prior art that the hydrosilylation reaction is accompanied, as is known, by the transfer of the chlorine, alkoxy or amino functionalities to the hydrosilylation catalyst or the compounds of the formula (1), which indicates the achievable yield in the hydrosilylation process the state of the art so limited that, in particular for the implementation of such mixtures satisfactory technical solutions are missing so far. In view of the technical significance of these chlorine-, alkoxy- or amino-functionalized hydrosilylation products, the solution according to the invention of this problem has considerable economic potential.

The instant process of this invention demonstrates an unexpected technical solution based on the discovery that the solution of a transition metal complex used as a hydrosilylation catalyst in an ionic liquid surprisingly catalyzes selectively a hydrosilylation of non-polymeric Si-H compounds in a multi-phase reaction regime. The process according to this invention also offers a technically reliable possibility of catalyst separation and recirculation in the liquid-liquid two-phase system. With multiple recirculation of the ionic liquid, only slight changes in the activity and selectivity of the ionic catalyst solution are observed. In the preferred variants of the method according to the invention which are shown below, the changes are particularly slight.

In a particularly preferred embodiment of the method according to this invention are as Si-H compounds according to the Formula (3) the compounds HSiCl ₃ , HSiCl ₂ Me, HSiClMe ₂ , HSiCl ₂ Et and HSiClEt ₂ , HSi (OMe) ₃ , HSi (OEt) ₃ , HSi (OMe) ₂ Me, HSi (OEt) ₂ Me, HSi (OMe) Me ₂ and HSi (OEt) Me ₂ used.

In a further preferred embodiment of the process according to this invention, alkenes used are propene, allyl chloride, acetylene, ethylene, isobutylene, cyclopentene, cyclohexene and 1-hexadecene.

In a particularly preferred embodiment of the process, HSiCl ₃ and HSiMeCl _{2 are} used as Si-H compound and allyl chloride as alkene component.

In a preferred embodiment of the process according to this invention are used as the catalyst complex compound of

Platinum, iridium or rhodium used. Particularly preferred are the complex compounds of platinum, in particular the complexes PtCl ₄ and H ₂ PtCl ₆ .

In a preferred embodiment of the method according to this invention is used as the ionic liquid, an ionic liquid of the general formula (4)

[A] ⁺ [Y] - (4)

in which

[Y] - an anion is selected from the group comprising [tetrakis (3, 5-bis (trifluoromethyl) phenyl) borate], ([BARF]), tetraphenylborate ([BF ₄ ] ^" ), hexafluorophosphate ([PF ₆ ] ^" ), trispentafluoroethyltrifluorophosphate ([P (C ₂ F ₅ ) ₃ F ₃ ] ^" ), hexafluoroantimonate ([SbF ₆ ] ^" ), hexafluoroarsenate ([AsF ₆ ] ^" ), fluorosulfonate, [R '-COO] ^" , [R'-SO _3] ^", [R'-O-SO _^3]" [R _'2 PO _4] ^", or [(R' SO ₂₎ ₂ N] -, where R 'is a linear or branched aliphatic or alicyclic alkyl containing 1 to 12 carbon atoms, a C5-C18-aryl or a C-C8-C5-aryl-C1-C6-alkyl radical whose hydrogen atoms are wholly or partly substituted by fluorine atoms and [A] ⁺ a cation is selected from the group comprising ammonium cations of the general formula (5)

[NR ¹ R ² R ³ R ₄ ]! 5)

Phosphonium cations of the general formula (6;

[PR ¹ R ² R ³ R ₄ ]

Imidazole ium cations of the general formula (7)

Pyridinium cations of the general formula (8)

Pyrazolium cations of the general formula (9)

Triazolium cations of the general formula (10 ^'

Picolinium cation of the general formula (H)

and

Pyrrolidinium cation of the general formula (12 ^'

: I2) wherein the radicals R ^1'7 each independently represent organic radicals having 1-20 C atoms.

The radicals R ^1'7 are preferably aliphatic, cycloaliphatic, aromatic, araliphatic or oligoether groups.

Aliphatic groups are straight-chain or branched hydrocarbon radicals having from one to twenty carbon atoms, it being possible for heteroatoms, such as, for example, oxygen, nitrogen or sulfur atoms, to be present in the chain.

The radicals R ^1'7 may be saturated or have one or more double or triple bonds which may be conjugated or isolated in the chain.

Examples of aliphatic groups are

Hydrocarbon groups having one to 14 carbon atoms, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl or n-decyl.

Examples of cycloaliphatic groups are cyclic hydrocarbon radicals having between three and twenty carbon atoms, which may contain ring heteroatoms, such as oxygen, nitrogen or sulfur atoms. The cycloaliphatic groups may also be saturated or have one or more double or triple bonds which may be conjugated or isolated in the ring. Saturated cycloaliphatic groups, especially saturated aliphatic hydrocarbons, having from five to eight ring carbon atoms, preferably five and six ring carbon atoms, are preferred. Aromatic groups carbocyclic-aromatic groups or heterocyclic-aromatic groups can have between six and twenty-two carbon atoms. Examples of suitable aromatic groups are phenyl, naphthyl or anthracyl.

Oligoethergruppen are groups of the general formula (13)

- [(CH ₂ ) _X -O] _y -R ^ΛΛΛ (13),

where x and y are independently of each other numbers between 1 and 250 and

R ^{ΛΛΛ represents} an aliphatic, cycloaliphatic, aromatic or araliphatic group.

In a further preferred embodiment, an ionic liquid is used whose cations [A] ⁺ can not be formed by deprotonation or oxidative addition of a C-H bond to a low-valence metal complex, metal complexes with N-heterocyclic carbene ligands. Particularly preferred cations of the ionic liquid used are N-alkylpyridinium and 1, 2, 3-trialkylimidazolium cations.

These cations [A] ⁺ in the particularly preferred embodiment of this invention are combined in particular with the anion [Y] ^- [(CF 3 SO 2) 2 N] ^- , so that the following ionic liquids are particularly preferred for use in the process according to the invention:

1-Ethylpyridiniumbistrifluoromethylsulfonylimide 1-Butylpyridiniumbistrifluoromethylsulfonylimide 1-Hexylpyridiniumbistrifluoromethylsulfonylimide 1-ethyl-3-methylpyridiniumbistrifluoromethylsulfonylimide 1-butyl-3-methylpyridiniumbistrifluoromethylsulfonylimide 1-hexyl-3-methylpyridiniumbistrifluoromethylsulfonylimide 1-ethyl-4-methylpyridiniumbistrifluoromethylsulfonylimide 1-butyl-4-methylpyridiniumbistrifluoromethylsulfonylimide 1-hexyl-4-methylpyridiniumbistrifluoromethylsulfonylimide 1-ethyl-2, 3 dimethylimidazoliumbistrifluoromethylsulphonylimide 1-butyl-2,3-dimethylimidazoliumbistrifluoromethylsulfonylimide 1-hexyl-2,3-dimethylimidazoliumbistrifluoromethylsulfonylimide

The inventive method is carried out as a two-phase reaction, wherein the catalyst can be used as a liquid phase and the reaction products as a liquid or gas phase.

In a preferred embodiment of the method, the

Transition metal complex dissolved in the ionic liquid and contacted with a non-miscible phase in the reactor, which contains the reaction product at the reactor outlet, so that the ionic catalyst solution is separated by phase separation in the process continuously and recycled to the reactor.

A further variant of the method consists in a Verfahrensfuhrung such that a film of the ionic

Catalyst solution is applied to a carrier material and the catalyst is brought into contact in this form in a gas phase reaction or in a Flussigphasenreaktion with the reaction mixture. This transfer of the known for other reactions SILP technology on the hydrosilylation of non-polymeric Si-H compounds according to formula (1) with alkenes according to formula (2) was surprisingly very successful, since this process variant, the first successful application of Pt-containing SILP Represents catalysts. It is further Surprisingly, despite the known sensitivity to water of the hydrosilylation reaction, the reaction with supported ionic catalyst solutions succeeds. The lack of deactivation of the sensitive transition metal catalyst or the possible deterioration of the product selectivity by interactions of the support with the catalyst could not be easily foreseen.

The described method can be carried out both without pressure and under pressure. Preferably, we carried out the process at a pressure of up to 200 bar, more preferably at a pressure of up to 20 bar.

Finally, the fact that for the particularly preferred variants of the process according to this invention an increased selectivity to the desired product of the hydrosilylation reaction is observed, is of particular surprising and of highest economic importance. This effect is attributed to the special solvent environment of the ionic liquid.

Examples

The abbreviations used in the following have the meaning shown here:

Cat catalyst

IL ionic liquid

HV high vacuum

Molar ratio silane too

Silane: AC allyl chloride

Pt-Conc platinum concentration Xl conversion allyl chloride X2 conversion trichlorosilane

Selectivity to the product: mol

Product / mol product + mol

S 1 tetrachlorosilane

Selectivity to Prosilan: mol

Prosilan / mol Prosilan + mol

S 2 tetrachlorosilane

Y yield

"TOF" turn-over-frequency

Tetra tetrachlorosilane

Prosilane Propyltrichlorosilane

[EMMIM] 1-ethyl-2,3-dimethylimidazolium

[BTA] Bistπfluoromethanesulfonylimides

Inductively Coupled Plasma

ICP-AES Atomic Emission Spectrometry

Example 1: Pressure-free Hydrosilylation Experiment with Ionic Liquid Using the Example of the Synthesis of 3-Chloropropyltrichlorosilane (Inventive)

In a heated flask (100-250 ml), about 10 ml of the ionic liquid l-ethyl-2, 3-dimethylimidazolium bistrifluoromethansulfonylimide presented. This is with constant stirring (magnetic stirrer) at 80 ⁰ C (external temperature control) in the HV pre-dried for one hour. If the ionic liquid is approximately moisture-free, weigh 17 mg of platinum tetrachloride (equivalent to 1500 ppmn). The ionic catalyst solution is added after the addition of

Catalyst dried again for one hour under vacuum at 80 ⁰ C. Subsequently, the three-necked flask is connected to the reflux condenser under continuous flow of protective gas and provided with a dropping funnel. The third port of the piston is closed with a contact thermometer for internal temperature control. If the apparatus is gas-tight, all newly connected system parts are dried in the HV. Thereafter, the remaining reactants (3-chloropropyltrichlorosilane: 5.6 g, allyl chloride 5.6 g and trichlorosilane: 12.5 g) are weighed out under a protective gas atmosphere. A template of the product lowers the vapor pressures of the educts. All reactants (3-chloropropyltrichlorosilane, allyl chloride and trichlorosilane) are tared for initial weighing in syringes and weighed after addition into the dropping funnel. The reaction temperature of 100 ⁰ C is set and controlled at the thermostat. The temperature of the intensive cooler (-20 ⁰ C) is generated by a cryostat. When the reaction temperature is reached, the reactants are carefully added from the dropping funnel (drop rate 5-40 drops / min). If the reaction temperature is exceeded by more than 10 ⁰ C, the addition is interrupted until the reaction temperature has returned to the set point. When the addition is complete, stirring is complete for 60 min

To ensure conversion of the reactants. Thereafter, ionic liquid and products are cooled in an ice bath. The content of the three-necked flask is added to a syringe for phase separation, organic phase (top) and ionic catalyst solution are separated and filled into separate vessels. It dissolves a small amount of the products in the ionic catalyst solution and can be removed in vacuo if desired. The organic phase is analyzed by gas chromatography. The amount of bled in the product phase platinum is determined by ICP-AES. Comparative Example 1 Pressure-Free Hydrosilylation Experiment Without Ionic Liquid (Not According to the Invention)

A three-necked flask (100-250 ml) is provided with dropping funnel and contact thermometer for internal temperature control and dried under high vacuum. Subsequently, 6.0 g of the product 3-chloropropyltrichlorosilane are placed under a protective gas atmosphere in the three-necked flask. Here at 80 ⁰ C (external temperature control) about 8.5 mg (equivalent to 600 ppmn Pt) of the organic catalyst complex (solution of PtC14 in 1-dodecene) under constant stirring (magnetic stirrer). Thereafter, the remaining reactants (allyl chloride: 6.40 g and trichlorosilane: 13.9 g) are weighed into the dropping funnel under a protective gas atmosphere. All reactants (3-chloropropyltrichlorosilane, allyl chloride and trichlorosilane) are tared for initial weighing in syringes and weighed after the addition. It is particularly important to pay attention to the correct ratio of the reactants. The reaction temperature of 100 ° C is set and controlled on the thermostat. The temperature of the intensive cooler (-20 ⁰ C) is replaced by a

Cryostats generated. When the reaction temperature is reached, the reactants are carefully added from the dropping funnel (drop rate 5-40 drops / min). If the reaction temperature is exceeded by more than 10 ⁰ C, the addition is interrupted until the reaction temperature has returned to the set point. When the addition is complete, stirring is continued for 60 minutes to ensure complete conversion of the reactants. After the reaction, the organic products are analyzed by gas chromatography.

Table 1 shows the results of Example 1 and Comparative Example 1. Table 1

Example 2: Hydrosilylation experiment with ionic liquid under pressure (according to the invention)

About 10 ml of the ionic liquid 1-ethyl-2,3-dimethylimidazoliumbistrifluoromethanesulphonylimide are initially introduced into a laboratory autoclave which has been dried under high vacuum and flooded with argon. 3.5 mg of platinum tetrachloride (equivalent to 300 ppmn) are weighed into the approximately moisture-free ionic liquid. The ionic catalyst solution is after the addition of the catalyst for one hour under vacuum at 100 ⁰ C (internal temperature control) dried. Thereafter, the remaining reactants (3-

Chloropropyltrichlorosilane: 11.63 g; Allyl chloride: 6.7 g and trichlorosilane: 13.4 g) under a protective gas atmosphere into a connected dropping funnel. All reactants (3-chloropropyltrichlorosilane, allyl chloride and trichlorosilane) are tared for initial weighing in syringes and weighed after addition into the dropping funnel. It is particularly important to pay attention to the correct ratio of the reactants. After filling, the reactor is placed under argon under the reaction pressure of 12 bar. The reaction temperature of 100 ° C is set on the heating jacket and controlled internally. When the reaction temperature has been reached, the reactants are added from the dropping funnel. After the end of the reaction (about 2 hours), the autoclave is carefully cooled in an ice bath to room temperature and then opened under argon flow. The contents are added to a syringe for phase separation, organic phase (top) and ionic catalyst solution are separated and filled into separate containers. It dissolves a small amount of the products in the ionic catalyst solution and can be removed in vacuo if desired. The organic phase is analyzed by gas chromatography. The amount of bled in the product phase platinum is determined by ICP-AES.

Comparative Example 2 Hydrosilylation Experiment Without Ionic Liquid Under Pressure (Not According to the Invention)

About 6.5 g of 3-chloropropyltrichlorosilane are placed in a laboratory autoclave, which has been dried under high vacuum and flooded with argon. 8.5 mg (equivalent to 600 ppmn of Pt) of the organic catalyst complex (solution of PtCl ₄ in 1-dodecene) are weighed into the approximately moisture-free liquid. Thereafter, the remaining reactants (allyl chloride: 6, 0 g and trichlorosilane: 13 g) are weighed under a protective gas atmosphere in a connected dropping funnel. All reactants (3-chloropropyltrichlorosilane, allyl chloride and trichlorosilane) are tared for initial weighing in syringes and weighed after the addition. It is particularly important to pay attention to the correct ratio of the reactants. After filling, the reactor is pressurized with argon under the system pressure of 12 bar. The reaction temperature of 100 ^° C. is set on the heating jacket and controlled internally. When the reaction temperature has been reached, the reactants are added from the dropping funnel. After the end of the reaction (about 2 hours), the autoclave is carefully cooled in an ice bath to room temperature and then opened under argon flow. The contents are added to a syringe for phase separation, organic phase (top) and ionic catalyst solution are separated and filled into separate containers. It dissolves a small amount of the products in the ionic catalyst solution and can be removed in vacuo if desired. The organic phase is analyzed by gas chromatography.

Table 2 shows the results of Example 2 and Comparative Example 2.

Table 2

Example 3 Pressure-Free Hydrosilylation Experiment with an Ionic Liquid Using the Example of the Synthesis of 3-Chloropropyltrichlorosilane (Inventive)

In a heated flask (100-250 ml), about 10 ml of the ionic liquid l-ethyl-2, 3-dimethylimidazolium bistrifluoromethansulfonylimide presented. This is predried with constant stirring (magnetic stirrer) at 80 ⁰ C (external temperature control) in the HV for one hour. When the ionic liquid is approximately moisture-free, 0.62 mg platinum tetrachloride (equivalent to 55 ppmn) is weighed. The ionic catalyst solution is post-dried after the addition of the catalyst again for one hour under vacuum at 80 ⁰ C. Subsequently, the three-necked flask is connected to the reflux condenser under constant protective gas flow and provided with a dropping funnel. The third port of the piston is closed with a contact thermometer for internal temperature control. If the apparatus is gas-tight, all newly connected system parts are dried in the HV. Thereafter, the remaining reactants (3-chloropropyltrichlorosilane: 5.6 g; allyl chloride 5, 6 g and

Trichlorosilane: 12.5 g) under a protective gas atmosphere. A template of the product lowers the vapor pressures of the educts. All reactants (3-chloropropyltrichlorosilane, allyl chloride and trichlorosilane) are tared for initial weighing in syringes and weighed after addition into the dropping funnel. The reaction temperature of 100 ⁰ C is set and controlled at the thermostat. The temperature of the intensive cooler (-20 ⁰ C) is generated by a cryostat. When the reaction temperature is reached, the reactants are carefully added from the dropping funnel (drop rate 5-40 drops / min). If the reaction temperature is exceeded by more than 10 ⁰ C, the addition is interrupted until the reaction temperature has returned to the set point. When the addition is completed, stirring is continued for 60 minutes to ensure complete conversion of the reactants.

Thereafter, ionic liquid and products are cooled in an ice bath. The content of the three-necked flask is added to a syringe for phase separation, organic phase (top) and ionic catalyst solution are separated and filled into separate vessels. It dissolves a small amount of the products in the ionic catalyst solution and can be removed in vacuo if desired. The organic phase is analyzed by gas chromatography. The amount of in the Product phase of bled platinum is determined by ICP-AES.

Example 4: Hydrosilylation with the SILP Technology (Inventive)

The carrier material used is a silica granulate (about 5 g) with a particle size distribution of 0.2 to 0.5 mm. Before the ionic liquid is applied, the support is calcined for several hours at 450 ^° C. and placed under protective gas while still hot. The ionic liquid 1-ethyl-3-methylimidazoliumbistrifluoromethanesulfonylimide (1.0 g) is already charged with the catalyst (PtCl ₄ : 0.7 mg, corresponding to 55 ppmn) and is dissolved in a 10-fold excess of methanol. The carrier material is combined with the IL-methanol solution and stirred until a homogeneous distribution can be ensured. In the final step, the methanol is carefully removed under vacuum and moderately elevated temperature (about 50 ⁰ C). This SILP catalyst is then dried under constant stirring (magnetic stirrer) at 80 ⁰ C (external temperature control) under HV for one hour.

A 3-necked flask (100-250 ml) is equipped with dropping funnel, reflux condenser and contact thermometer for internal temperature control. Between Ruckflusskuhler and three-necked flask here is a heated glass frit used to keep the catalyst. The entire apparatus is dried under high vacuum, including the SILP catalyst. If the apparatus is cooled, the dropping funnel is under constant inert gas stream with 6.3 g of allyl chloride and 11.7 g

Trichlorosilane is filled. All reactants (allyl chloride and trichlorosilane) are tared for initial weighing in syringes and weighed after addition into the dropping funnel. It In this case, pay particular attention to the correct ratio of the reactants. The reaction temperature of 100 ⁰ C is adjusted and regulated via the heating line of the glass frit. The temperature of the intensive cooler (-20 ⁰ C) is generated by a cryostat. The three-necked flask serves as an evaporator of the educts and is heated with an oil bath at 100 ⁰ C. When the reaction temperature is reached, the reactants are carefully added from the dropping funnel (drop rate 5-40 drops / min). If the reaction temperature is exceeded by more than 10 ⁰ C, the addition is interrupted until the

Reaction temperature has returned to the set point. After the reaction, the organic products are analyzed by gas chromatography. Residues of organic material adhering to the SILP can be separated off by means of vacuum or dry cyclohexane. The amount of bled in the product phase platinum is determined by ICP-AES.

Table 3 shows a comparison of Examples 3 and 4

Table 3

Example 5: Recycling Experiments (Inventive)

10 ml of the ionic liquid 1-ethyl-3-methylimidazolium bistrifluoromethanesulfonylimide are introduced into a heated flask (100-250 ml). This is predried with constant stirring (magnetic stirrer) at 80 ⁰ C (external temperature control) in the HV for one hour. When the ionic liquid is approximately moisture-free, 0.7 mg platinum tetrachloride (equivalent to 55 ppmn) is weighed. The ionic catalyst solution is added after the addition of

Catalyst dried again for one hour under vacuum at 80 ⁰ C. Following the three-necked flask is under continuous protective gas stream connected to the reflux condenser and provided with a dropping funnel. The third port of the piston is closed with a contact thermometer for internal temperature control. Sections which do not need to be operated during the reaction or preparation are additionally secured with parafilm. If the apparatus is gas-tight, all newly connected system parts are dried in the HV. Thereafter, the remaining reactants (allyl chloride: 6.4 g and trichlorosilane: 11.7 g) are weighed in a protective gas atmosphere. All reactants

(Allyl chloride and trichlorosilane) are tared for weighing in pre-weighed and weighed after addition to the dropping funnel. It is particularly important to pay attention to the correct ratio of the reactants. The reaction temperature of 100 ⁰ C is set and controlled at the thermostat. The temperature of the intensive cooler (-20 ⁰ C) is generated by a cryostat. When the reaction temperature is reached, the reactants are carefully added from the dropping funnel (drop rate 5-40 drops / min). If the reaction temperature is exceeded by more than 10 ⁰ C, the addition is interrupted until the reaction temperature has returned to the set point. When the addition is completed, stirring is continued for 60 minutes to ensure complete conversion of the reactants. Thereafter, ionic liquid and products are cooled in an ice bath. The content of the three-necked flask is added to a syringe for phase separation, organic phase (top) and ionic catalyst solution are separated and filled into separate vessels. It dissolves a small amount of the products in the ionic catalyst solution and can be removed in vacuo if desired. The organic phase is analyzed by gas chromatography. The amount of bled in the product phase platinum is determined by ICP-AES. The ionic liquid is introduced again without work-up into the apparatus and used again in the manner already described (preparation and amount of the reactants used) in the reaction. It is important to pay attention to sufficient protective gas technology. A drying of the ionic liquid in a vacuum can be omitted here. Such recycling can be successfully carried out for at least four steps.

Table 4 shows the results after the respective recycling. It can be seen that the reuse of the ionic catalyst solution leads to good results even after the third recycle.

Table 4

Claims

Claims:

1. A process for the preparation of silanes by hydrosilylation, characterized in that as

Catalyst of the hydrosilylation reaction of non-polymeric Si-H compounds, a transition metal complex compound is used which is dissolved in an ionic liquid during the reaction.

2. The method according to claim 1, characterized in that a complex compound of platinum, iridium or rhodium is used as the catalyst of the hydrosilylation reaction.

3. The method according to claim 1 or 2, characterized in that in the hydrosilylation, the non-polymeric Si-H compounds of the general formula (1)

H _a SiR _b (1),

with alkenes of the general formula 2

R ⁸ R ⁹ C = CR ¹⁰ R ¹¹ (2),

be implemented, where

R independently of one another H, a monovalent Si-C bonded, optionally halogen-substituted C _] _-

C] _g-hydrocarbon, chlorine, or C] _C] _g alkoxy, a 1,2 or 3, b 4-a, R ⁸ , R ⁹ , R ¹⁰ and R ^{11 are} independently H, one monovalent optionally with F, Cl, OR, NR 2, CN or NCO substituted C] _C] _g hydrocarbon, chlorine, fluorine or C] _- C] _g alkoxy radical, wherein in each case 2 radicals of R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ together with the carbon atoms, to which they are attached, can form a cyclic radical.

4. The method according to any one of claims 1 to 3, characterized in that is used as the ionic liquid, an ionic liquid of the general formula (4)

[A] ⁺ [Y] 'A)

in which

[Y] ^~ the anion is selected from the group consisting of [tetrakis (3, 5-bis- (trifluoromethyl) -phenyl) borate], ([BARF]), tetraphenylborate ([BF _4] ^"), hexafluorophosphate ([PF ₆ ] ^~ ), trispentafluoroethyltrifluorophosphate ([P (C ₂ Fs) ₃ F ₃ ] ^" ),

Hexafluoroantimonate ([SbF ₆ ] ^" ), hexafluoroarsenate ([AsF ₆ ] ^" ), fluorosulfonate, [R ^' -COO] ^" , [R' -SO ₃ ] ^" , [R ^' -O-SO ₃ ] ^" , [R '2-PO ₄ ] ^' , or [(R '-SO ₂ ) ₂ N] -, where R' is a linear or branched aliphatic or alicyclic alkyl, C 5 -C 18 aryl or C 5 containing 1 to 12 carbon atoms C18-aryl-C1-C6-alkyl radical whose hydrogen atoms may be wholly or partially substituted by fluorine atoms, and [A] ⁺ the cation is selected from the group consisting of ammonium cations of general formula (5) [NR ¹ R ² R ³ R ₄ ]: 5)

Phosphonium cations of the general formula (6)

Imidazolium cations of the general formula (7)

Pyridinium cations of the general formula (8)

Pyrazolium cations of the general formula (9)

Triazolium cations of the general formula (10)

Picolinium cation of the general formula (11)

and

Pyrrolidinium cation of general formula (12)

where the radicals Ril-7 in each case independently of one another represent organic radicals having 1-20 C atoms.

5. The method according to any one of claims 1 to 4, characterized in that it is carried out as a two-phase reaction, wherein the catalyst is used as the liquid phase and the reaction products as a liquid or gas phase.

6. The method according to any one of claims 1 to 5, characterized in that the catalyst is dissolved in the ionic liquid and contacted with a non-miscible phase in the reactor, which contains the reaction product at the reactor outlet, so that the ionic

Catalyst solution is separated by phase separation in the process continuously and recycled back into the reactor.

7. The method according to any one of claims 1 to 6, characterized in that a film of the ionic catalyst solution is applied to a support material and the catalyst is brought into contact in this form in a gas phase reaction or in a liquid phase reaction with the reaction mixture.