DE102005030581A1 - Preparation of organosilane compounds, useful as e.g. coupling agents, comprises reacting silane compounds with alkene and/or alkyne in the presence of iridium compound and cocatalyst (inorganic/metalorganic/organic oxidation agents) - Google Patents

Abstract

Preparation of organosilane compounds (I) comprises reacting silane compound (II) with alkene and/or alkyne (III) in the presence of iridium compound as catalyst and cocatalyst (inorganic-; metalorganic-; or organic oxidation agents), where the cocatalyst used in 0.5-5 wt.%, related to the total weight of (II) and (III). Preparation of organosilane compounds (I) of formula R 6>R 5>CH-R 4>CH-SiR 1>R 2>R 3>comprises reacting silane compound (II) of formula HSiR 1>R 2>R 3>with alkene and/or alkyne (III) of formula R 6>R 5>CH=CHR 4>in the presence of iridium compound as catalyst and cocatalyst (inorganic oxidation agent of oxygen, chlorine, bromine, iodine, peracid, peroxide, bromate, chlorate, iodate, perchlorate, potassium chromate, potassium dichromate, potassium permanganate, sodium peroxodisulfate, potassium perrhenate or potassium hexacyanoferrate(III); metalorganic oxidation agent of: ferricinium, ruthenium complex of formula [Ru(bipyridine) 3] 3 +>or iron complex of formula [Fe(phenanthroline) 3] 3+>; or organic oxidation agent of: aldehyde, acetone, methyl isobutyl ketone, acetylacetone, 1,4-cyclohexane dione, 1,3-cyclohexane dione, 1,2-cyclohexane dione, 1,9-cyclohexadecane dione, benzil, triketone, naphthoquinone, organic peroxide and peracid, crown ether, phosphane oxide, sulfone, tritylium salt or tropylium salt), where the cocatalyst used in 0.5-5 wt.%, related to the total weight of (II) and (III). R 1>-R 3>univalent Si-C bound, optionally halo substituted 1-18C hydrocarbon, Cl or 1-18C alkoxy; either R 4>-R 6>H, univalent 1-18C hydrocarbon (optionally substituted with F, Cl, OR, N(R) 2, CN or NCO), Cl, F or 1-18C alkoxy (where two of R 4>-R 6>residue together with the hydrocarbon forms a cyclic residue); or R 4>+R 5>bond between the C to which they are bound; and R : H or univalent 1-18C hydrocarbon.

Description

The The invention relates to a continuous process for the preparation of organosilanes by hydrosilylation of S-bonded hydrogen atoms having silanes on alkenes in the presence of iridium compounds as catalysts and cocatalysts.

substituted Alkyl silanes are of tremendous economic interest to a large number of areas. They are used z. B. as a primer, as Crosslinkers or as precursors for further chemical reactions, such as hydrolyses or nucleophilic substitution reactions.

The Platinum- or rhodium-catalyzed hydrosilylation of unsaturated, Halogen-substituted compounds have been studied many times Service. The product yields are often very low at 20-45%, which is is due to significant side reactions. A mainly occurring here Side reaction is the replacement of a hydrogen atom with a Halogen atom on the silicon.

Iridium catalysts with diene ligands according to US-A-4,658,050 to the Hydrosilylation of allyl compounds with alkoxy-substituted Used silanes. Chemical Abstracts 123: 340390 describes hydrosilylation of allyl halides with chlorodimethylsilane in the presence of Iridium catalysts with diene ligands. Disadvantages of these processes are either moderate yields, an uneconomically high catalyst concentration and / or a very short life of the catalyst.

In EP-A-1 156 052 and US-A-6,388,119 (corresponding DE-C-100 53 037) and DE-C 10232663 will be the addition of additional Dienliganden for extension described the catalyst life. The disadvantage of these cocatalyst / catalyst combinations is however, that they rapidly lose their hydrosilylation activity, as soon as the silane element having Si-H groups in molar excess to olefin, the alkene is present. These fluctuations in the Eduktmischung occur in particular in the ongoing continuous Production process on and it comes to the sleep of the reaction. This represents a major safety issue Risk.

It Therefore, the task was a catalyst system with a long service life to develop which ensures high product yields and purities, while avoiding the disadvantages described above and thus avoiding the procedural and safety aspects.

The Task is solved by the invention.

The invention relates to a continuous process for the preparation of silanes of the general formula I. R ⁶ R ⁵ CH-R ⁴ CH-SiR ¹ R ² R ³ (I), in the silane of the general formula II HSiR ¹ R ² R ³ (II), with alkenes or alkynes of the general formula III R ⁶ R ⁵ C = CHR ⁴ (III), in the presence of iridium compounds as catalysts and in the presence of cocatalysts which act oxidatively on the iridium atom in the catalyst and which can optionally coordinate via a heteroatom selected from the group of oxygen, nitrogen, sulfur and phosphorus to the iridium atom in the catalyst, wherein the cocatalysts in Amounts of from 0.1% by weight to 5.0% by weight, preferably from 0.5% by weight to 5.0% by weight, based on the total weight of the components of the general formula (II) and ( III), are used
be implemented continuously, with
R ¹ , R ² , R ^{3 is} a monovalent Si-C bonded, optionally halogen-substituted C ₁ -C ₁₈ -hydrocarbon hydrogen, chlorine, or C ₁ -C ₁₈ alkoxy,
R ⁴ , R ⁵ , R ^{6 is} a hydrogen atom, a monovalent optionally substituted by F, Cl, OR, NR ₂ , CN or NCO C ₁ -C ₁₈ hydrocarbyl, chloro, fluoro or C ₁ -C ₁₈ alkoxy in which in each case 2 radicals of R ⁴ , R ⁵ , R ⁶ together with the carbon atoms to which they are attached can form a cyclic radical,
or wherein R ⁴ and R ⁵ together may represent a bond between the carbon atoms to which they are attached [such as a triple bond between the two C atoms in the alkyne of formula III and a double bond between the two C atoms in the silane of the formula (I)] and
R is a hydrogen atom or a monovalent C ₁ -C ₁₈ hydrocarbon radical
mean and
wherein the reaction temperature is 0 ° C to 40 ° C, preferably 20 ° C to 40 ° C, and the temperature of the reaction mixture is maintained at these temperatures.

One preferred method is the start of the reaction at 35 ° C to 40 ° C and the Lowering the reaction temperature to 20 ° C to 30 ° C after the exothermic start the hydrosilylation reaction.

The continuous process is preferably carried out at the pressure of the surrounding The atmosphere, that is, at about 0.10 MPa, but it can also be higher or lower pressures carried out become. The reaction pressure may therefore preferably be from 0.10 to 50 MPa, preferably 0.10 to 2.0 MPa.

The continuous process provides the silane of the general formula (I) in high yields and excellent in purity.

at In the continuous process, the target products are the general ones Formula (I) in the use of very small amounts of catalyst in yields from preferably 90% to 99%, based on the silane used, preferably chlorosilane, of the formula (II). In the continuous Process can be the allyl chloride excess preferably be significantly reduced. The formation of the corresponding Silane by-products due to hydrogen - chlorine exchange can be significant be lowered. In addition, the process is easy to control and perform safely.

When technical versions to carry out of the method are all common Reactors for continuous reaction, z. B. tube and loop reactors and continuously operated stirred reactors or combinations of these Reactor types, such as loop tube reactor, tube loop tube reactor, tube stirred tank reactor, continuous stirred cell reactor, continuous reactive distillation in vacuo at low temperatures etc., whereby the tube reactors over static and / or dynamic stirrers may have. Also suitable are microreactors with channel sizes from 1 micron to some Millimeter. The different reactors must have a suitable cooling device feature, to quantitatively dissipate the heat generated during the exothermic reaction and thus to keep the reactor or reaction temperature less than 40 ° C. Suitable refrigeration units are e.g. internal cooling coils, Tube or plate heat exchanger in the loop circuit, etc.

alternative or supportive for heat dissipation from the reactor, a reactant or all starting materials in the continuous Process by suitable heat exchangers pre-cooled are, preferably to temperatures of -20 ° C to 30 ° C, preferably 0 ° C to 15 ° C. suitable heat exchangers are again plate or tube heat exchangers, etc., and micro heat exchanger with a channel cross-section of 1 micron to 10 millimeters.

at the order of metering of the reaction components are in principle all conceivable combinations possible, in particular can the components are partly premixed introduced into the reactor.

Prefers Here is the preliminary mixing of the iridium catalyst with the cocatalyst and the alkene of the formula (III). Preferably, the iridium catalyst is not in an environment of surplus on silane of the formula (II) the alkene of the formula (III), since the iridium catalyst otherwise show deactivation can.

A another possibility consists in an optionally tempered premix of all components in a continuous active or static mixing unit, such as static mixing elements, Pentax or planetary mixers or micromixing elements with subsequent transfer of this Reaction mixture in a downstream reaction zone, which in turn is designed continuously, z. B. as a tube reactor, loop reactor, Etc.

For example in the continuous process, the silanes of the formula become (II) optionally in admixture with the cocatalyst over a Line and a mixture of alkenes of formula (III), iridium catalyst and cocatalyst over another line continuously into a reactor, e.g. loop reactor or continuous stirred tank, added. The temperature is initially lowered from 40 ° C to 30 ° C.

In another embodiment is to retract the reactor, the target product of formula (I) or an aprotic solvent presented together with the iridium catalyst and the cocatalyst at 35 ° C. and a mixture of alkene of formula (III) and optionally Cocatalyst over a line and the silane of formula (II) via a different line continuously added. After the reaction has started, the reaction mixture at 25 ° C cooled.

at the continuous process becomes the one formed after the reaction Silane of the general formula (I) continuously from the reactor executed.

The averaged residence times of the reactor contents are preferably at 0.5 to 60 minutes and are from the respective reaction temperature dependent.

Iridium compounds of general formula IV are preferred in the continuous process [(Diene) IrX] ₂ (IV), used as catalysts,
in which
X represents a halogen atom such as chlorine, bromine or iodine, or a hydroxy group or a methoxy group, and
Diene is an optionally substituted by F, Cl, OR, NR ₂ , CN or NCO C ₄ -C ₅₀ hydrocarbon compound having at least two ethylenic C = C double bonds, wherein R has the meaning given above, means.

C ₁ -C ₁₈ -hydrocarbon radicals R ¹ , R ² , R ^{3 are} preferably alkyl, alkenyl, cycloalkyl or aryl radicals. Preferably, R ¹ , R ² , R ^{3 have} at most 10, in particular at most 6 carbon atoms. Preferably, R ¹ , R ² , R ^{3 are} straight-chain or branched C ₁ -C ₆ -alkyl radicals or C ₁ -C ₆ -alkoxy radicals. Preferred halogen substituents are fluorine and chlorine. Particularly preferred as R ¹ , R ² , R ³ are the radicals methyl, ethyl, methoxy, ethoxy, chlorine, phenyl and vinyl.

preferred examples for Silanes of the formula II are chlorosilanes, particularly preferred is dimethylchlorosilane.

Hydrocarbon radicals R ⁴ , R ⁵ , R ^{6 are} preferably alkyl, alkenyl, cycloalkyl or aryl radicals. Preferably, at most one of the hydrocarbon radicals R ⁴ , R ⁵ , R ^{6 is} an alkoxy radical. Preferably, R ⁵ , R ^{6 have} at most 10, in particular at most 6 carbon atoms. Preferably, R ⁵ , R ^{6 have} at most 10, in particular at most 6 carbon atoms. Preferably, R ⁵ , R ^{6 are} straight-chain or branched C ₁ -C ₆ -alkyl radicals, chlorine-substituted C ₁ -C ₆ -alkyl radicals or C ₁ -C ₆ -alkoxy radicals. Particularly preferred as R ⁵ , R ⁶ are the radicals hydrogen, methyl, ethyl, chlorine, phenyl and chloromethyl.

Preferably, the hydrocarbon radical R ⁴ at most 6, especially at most 2 carbon atoms. Particularly preferred as R ⁴ are the radicals hydrogen, methyl, ethyl.

Preferably has hydrocarbon radical R at most 6, in particular at most 2 carbon atoms.

One preferred example of Alkene of the formula III is allyl chloride.

In the method according to the invention, instead of an alkene, an alkyne can be used, which is not preferred. The radicals R ⁴ and R ⁵ then together form a bond between the two carbon atoms to which they are attached in formula III and the alkyne has the following formula R ⁶ C = CH (R ⁶ has the meaning given above) , This results in a silane of the formula (I) in which the two radicals R ⁴ and R ⁵ then also together form a bond between the two carbon atoms to which they are attached.

The As diene designated ligands in the formula (IV) can besides the molecular units having the ethylenic C = C double bonds still alkyl, cycloalkyl or Aryleinheiten have. Preferably the dienes have 6 to 12 carbon atoms. Preferred are mono- or bicyclic dienes. Preferred examples of dienes are butadiene, 1,3-hexadiene, 1,4-hexadiene, 1,5-hexadiene, isoprene, 1,3-cyclohexadiene, 1,3-cyclooctadiene, 1,4-cyclooctadiene, 1,5-cyclooctadiene and norbornadiene.

In a particularly preferred case, the catalyst of general formula IV used is [(cycloocta-1c, 5c-diene) IrCl] ₂ .

When Cocatalysts according to the invention are all substances that have a redox potential, the enough to the iridium atom of the catalyst compound from a reduced into an oxidative state.

Examples for oxidative Cocatalysts are inorganic, organometallic and organic Oxidant.

Examples for inorganic Oxidizing agents are oxygen, chlorine, bromine, iodine, peracids, peroxides, bromate, Chlorate, iodate, perchlorate, potassium chromate, potassium dichromate, potassium permanganate, Sodium peroxodisulfate, potassium perrhenate and potassium hexacyanoferrate (III).

Examples of organometallic oxidants are ferricinium, [Ru (bipyridine) ₃ ] ³⁺ and [Fe (phenanthroline) ₃ ] ³⁺ . Examples of organic oxidizing agents are aldehydes such as benzaldehyde, acetaldehyde and cinnamaldehyde;
Ketones such as aliphatic ketones such as acetone and MIBK (methyl isobutyl ketone); cyclic ketones such as cyclohexanone and methylcyclohexanone; aromatic ketones such as acetophenone and benzophenone;
Diketones such as linear and cyclic diketones such as acetylacetone, 1,4-cyclohexanedione, 1,3-cyclohexanedione, 1,2-cyclohexanedione, 1,9-cyclohexanedicarband and benzil;
Triketones such as 1,5-diphenyl-1,3,5-pentanetrione and 2,2,4,4,6,6-hexamethyl-1,3,5-cyclohexanetrione;
Quinones such as p-benzoquinone, naphthoquinone and anthraquinone; organic peroxides and peracids;
crown ethers; Phosphine oxides such as triphenylphosphine oxide and trimethylphosphine oxide; Sulfones, such as dimethylsulfone and diphenylsulfone; Tritylium salts, such as [Ph ₃ C] [BF ₄ ]; and
Tropylium salts, such as [C ₇ H ₇ ] [BF ₄ ].

Prefers cocatalysts are organic oxidizing agents, such as aldehydes, Ketones, diketones, quinones and organic and inorganic peroxides.

Especially preferred cocatalysts are aldehydes, acetone, methyl isobutyl ketone, Acetylacetone, 1,4-cyclohexanedione, 1,3-cyclohexanedione, 1,2-cyclohexanedione, 1,9-cyclohexadecanedione, benzil, naphthoquinone and organic and inorganic peroxides.

The Alkene of the general formula III is preferably in excess from 0.01 to 100 mol%, particularly preferably 0.1 to 25 mol%, based reacted to the silane component of general formula II.

The iridium compound used as the catalyst, preferably the iridium compound of the general formula IV, is preferably used in amounts of 3 to 10 000 ppm by weight, preferably 20 to 1000 ppm by weight, particularly preferably 50 to 500 ppm by weight, calculated as elemental iridium and based on the total weight of the present in the reaction mixture Components of the formula II and III used.

Of the oxidative cocatalyst is preferably used in amounts of from 0.5 to 2.5 wt .-%, preferably 1.0 to 2.0 wt .-%, each based on the Total weight of the components present in the reaction mixture of the formula II and III used.

The inventive method may be in the presence or absence of aprotic solvents carried out become.

If aprotic solvents are used, preference is given to solvents or solvent mixtures having a boiling point or boiling range of up to 120 ° C. at 0.1 MPa. Examples of such solvents are chlorinated hydrocarbons, such as dichloromethane, trichloromethane, carbon tetrachloride, 1,2-dichloroethane, trichlorethylene; Hydrocarbons, such as pentane, n-hexane, hexane isomer mixtures, heptane, octane, benzine, petroleum ether, benzene, toluene, xylenes; Esters, such as ethyl acetate, butyl acetate, propyl propionate, Ethyl butyrate, ethyl isobutyrate; Carbon disulfide and nitrobenzene, or mixtures of these solvents.

Prefers Be no aprotic solvent concomitantly.

When aprotic solvent can in the process according to the invention also the target product of general formula I are used, i.e. the reacted reaction mixture can also be used as solvent serve. The advantage here is that no further substances in the reaction system be registered.

In the following examples are, unless stated otherwise, all quantities and percentages by weight, all pressures 0.10 MPa (abs.) And all temperatures 20 ° C.

Examples 1 to 5 (B1-B5) and Comparative Experiments 1 and 2 (V1 and V2)

In a stirred at 35 ° C continuous stirred tank with a reactor volume of 5 1 are via a metering dimethylchlorosilane (HM2) with 1 wt .-% of cocatalyst specified in the table on the one hand and another metering a mixture of 2.7 × 10 ^{- 3} mol% of di-μ-chloro-bis - [(cycloocta-1c, 5c-diene) iridium (I)] in allyl chloride and 0.5 wt .-% of the cocatalyst indicated in the table on the other hand in a molar ratio of silane to Allyl chloride of 1: 1.05 at a rate of 2 1 / h (based on the total volume of the metered components) added. After the exothermic start of the reaction, the reactor contents are cooled within 30 minutes to the target temperature indicated in the table.

The Yields of the obtained target product chloropropyldimethylchlorosilane (= ZP) and the amount of by-produced dimethyldichlorosilane (= M2) and dimethylpropylchlorosilane (= NP1) are given in the table.

• * Angaben beziehen sich auf die Flächenprozent aus GC-Analysen und sind normiert auf den gesamten Chlorsilan Anteil
• ¹⁾ ZP = Chlorpropyldimethylchlorsilan
• ²⁾ M2 = Dimethyldichlorsilan
• ³⁾ NP1 = Dimethylpropylchlorsilan
• ⁴⁾ MIBK = Methylisobuthylketon

The comparative experiments V1 and V2, in which after the exothermic start of the reaction, the reactor contents were not cooled and the reaction took place at 80 ° C and 60 ° C show a significantly lower yield of the target product and an increase in the proportion of undesirable by-products. Table:

• * Data refer to the area percentage from GC analyzes and are normalized to the total chlorosilane content
• ¹⁾ ZP = chloropropyldimethylchlorosilane
• ²⁾ M2 = dimethyldichlorosilane
• ³⁾ NP1 = dimethylpropylchlorosilane
• ⁴⁾ MIBK = methyl isobuthyl ketone

Claims (14)

Process for the continuous production of silanes of the general formula I R ⁶ R ⁵ CH-R ⁴ CH-SiR ¹ R ² R ³ (I), in the silane of the general formula II HSiR ¹ R ² R ³ (II), with alkenes or alkynes of the general formula III R ⁶ R ⁵ C = CHR ⁴ (III) in the presence of iridium compounds as catalysts and in the presence of cocatalysts which act oxidatively on the iridium atom in the catalyst and which can optionally coordinate via a heteroatom selected from the group of oxygen, nitrogen, sulfur and phosphorus to the iridium atom in the catalyst, wherein the cocatalysts in Amounts of from 0.1% by weight to 5.0% by weight, based on the total weight of the components of the general formula (II) and (III) used, can be reacted continuously, where R ¹ , R ² , R ^{3 is} a monovalent Si-C bonded, optionally halogen-substituted C ₁ -C ₁₈ -hydrocarbon, chlorine, or C ₁ -C ₁₈ -alkoxy, R ⁴ , R ⁵ , R ^{6 is} a hydrogen atom, a monovalent optionally with F, Cl , OR, NR ₂ , CN or NCO substituted C ₁ -C ₁₈ hydrocarbyl, chloro, fluoro or C ₁ -C ₁₈ alkoxy, wherein in each case 2 radicals of R ⁴ , R ⁵ , R ⁶ together with the carbon atoms to which they are bound may form a cyclic radical, or wherein R ⁴ and R ⁵ together may represent a bond between the carbon atoms to which they are attached and R represents a hydrogen atom or a C ₁ -C ₁₈ monovalent hydrocarbon radical and wherein the reaction temperature is 0 ° C is up to 40 ° C and the temperature of the reaction mixture is maintained at these temperatures. Method according to claim 1, characterized in that that the reaction is started at a temperature of 35 ° C to 40 ° C and after the exothermic start of the reaction, the reaction mixture to a temperature from 20 ° C up to 30 ° C chilled becomes. Method according to claim 1 or 2, characterized that the continuous process is selected in a reactor the group of tube reactors, loop reactors, continuously operated Stirring reactors and combinations of these reactors is performed. Method according to claim 3, characterized that the reactors are a cooling device contain. Method according to one of claims 1 to 4, characterized that in the reactor over a line silane of the general formula (II) optionally in Mixture with the cocatalyst is metered in and over a another line a mixture of alkene of the general formula (III), Catalyst and cocatalyst is added. Method according to one of claims 1 to 5, characterized that the silane formed after the reaction of the general formula (I) is carried out continuously from the reactor. Method according to one of claims 1 to 6, characterized in that as cocatalysts selected from the group of inorganic oxidizing agents selected from the group consisting of oxygen, chlorine, bromine, iodine, peracids, peroxides, bromate, chlorate, iodate, perchlorate, potassium chromate, Potassium dichromate, potassium permanganate, sodium peroxodisulfate, potassium perrhenate and potassium hexacyanoferrate (III); organometallic oxidants selected from the group of ferricinium, [Ru (bipyridine) ₃ ] ³⁺ and [Fe (phenanthroline) ₃ ] ³⁺ ; and organic oxidizing agents selected from the group of aldehydes, ketones, diketones, triketones, quinones, organic peroxides and peracids, crown ethers, phosphine oxides, sulfones, tritylium salts and tropylium salts. Method according to one of claims 1 to 7, characterized in that cocatalysts are those selected from the group of aldehydes, Ketones, diketones, quinones and organic and inorganic peroxides be used. Method according to one of claims 1 to 8, characterized in that cocatalysts are those selected from the group of aldehydes, Acetone, methyl isobutyl ketone, acetylacetone, 1,4-cyclohexanedione, 1,3-cyclohexanedione, 1,2-cyclohexanedione, 1,9-cyclohexadecanedione, benzil, naphthoquinone and organic and inorganic peroxides are used. Method according to one of claims 1 to 9, characterized in that as iridium compounds of the general formula IV [(Diene) IrX] ₂ (IV) wherein X represents a halogen atom, a hydroxy group or a methoxy group, diene means a C ₄ -C ₅₀ hydrocarbon compound optionally substituted by F, Cl, OR, NR ₂ , CN or NCO and having at least two ethylenic C = C double bonds, and R has the meaning given in claim 1, are used. Method according to one of claims 1 to 10, characterized in that as the catalyst of the general formula IV [(cycloocta-1c, 5c-diene) IrCl] _{2 is} used. Method according to one of claims 1 to 11, characterized in that R ¹ , R ² , R ^{3 are} C ₁ -C ₆ -alkyl radicals or C ₁ -C ₆ -alkoxy radicals. Method according to one of claims 1 to 12, characterized in that R ⁵ , R ^{6 are} C ₁ -C ₆ -alkyl radicals, chlorine-substituted C ₁ -C ₆ -alkyl radicals or C ₁ -C ₆ -alkoxy radicals. Method according to one of claims 1 to 13, characterized in that R ^{4 is} a hydrogen atom, a methyl radical or an ethyl radical,