JPH0367738B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD OF THE INVENTION The present invention relates to the production of silanes by disproportionation and/or redistribution reactions of chlorohydrogenated silanes,
In particular, it relates to a method for producing a catalyst useful for this reaction. Conventional technology Conventionally, quaternary phosphonium salts of the type bonded to organic polymers include types in which a phosphorus atom is directly bonded to an aromatic nucleus (phenyl type), or types in which a phosphorus atom is bonded to an aromatic nucleus via one methylene group. type (benzyl type) was common. However, these bond type phosphonium salts are unstable under the chlorosilane disproportionation reaction conditions and therefore have a problem in their ability to maintain activity. On the other hand, if the crosslinking group between the phosphorus atom and the organic polymer is a dimethylene group (-CH ₂ CH ₂ -) or more, and the remaining bonding group of the phosphorus atom is a primary alkyl group, this phosphonium salt becomes extremely Having found that it is stable, the present inventors filed a patent application (Japanese Patent Application No. 60-210325).
(See Special Publication No. 64-3808). To synthesize a phosphonium salt having such a structure, conventional methods use a combination of polystyrene, tetramethylethylenediamine, an organolithium reagent, a dihaloalkane, and a trialkylphosphine, or a combination of polystyrene, a brominated polystyrene, an organolithium reagent, and a dihaloalkane. and trialkylphosphine as raw materials, but these methods
The drawback was that the organolithium reagent was expensive and dangerous to handle. Problems to be Solved by the Invention In the present invention, metallic lithium, which is safe and easy to handle, is used instead of using an organic lithium reagent which is dangerous and expensive to handle. Organolithium reagents are highly reactive and easily decompose when they come into contact with air, and sometimes spontaneously ignite, posing a risk of fire. Means for Solving the Problems In order to solve the above problems, the present inventors conducted extensive research and found a synthetic route using metallic lithium, which is safer and cheaper than organic lithium, and completed the present invention. That is, in the present invention, an organic polymer compound in which a halogen atom is directly bonded to an aromatic nucleus is prepared by combining metal lithium and the general formula X-(CH ₂ -) _o X' in a solvent.
X' represents the same or different halogen atoms, n represents a number from 2 to 10] to obtain an organic polymer compound in which the aromatic nucleus is ω-haloalkylated by contacting with an α,ω-dihaloalkane represented by a) and the ω−
An organic polymer comprising a step (b) of reacting a haloalkylated organic polymer with a trialkylphosphine -(CH ₂ -) _o (n=2 to 10)
The present invention relates to a method for producing a chlorosilane disproportionation reaction catalyst to which a tetraalkylphosphonium salt having a methylene group as a bridging group is bonded. In the method of the present invention, a dihaloalkane reacts with metallic lithium to produce an organolithium reagent, which, for example, lithiates brominated polystyrene and returns itself to an α,ω-dihaloalkane and reacts with metallic lithium again. The process of producing an organolithium reagent and lithiation of brominated polystyrene is repeated until metallic lithium is consumed. Thereafter, the lithiated aromatic nucleus reacts with the regenerated dihaloalkane to cause ω-haloalkylation, while producing lithium halide. Therefore, the present invention simplifies the steps and avoids the use of organolithium reagents, thereby avoiding operational hazards and resulting in a more economical process. The solvent used in step (a) above is usually preferably an ether solvent, particularly diethyl ether.
Further, the reaction temperature is preferably 0 to 40°C. In addition, the α,ω-dihaloalkane represented by the above general formula includes 1,2-dibromoethane, 1,3-
dibromopropane, 1,4-dibromobutane,
1,5-dibromopentane, 1,6-dibromohexane, 1,7-dibromoheptane, 1,8-dibromooctane, 1,10-dibromodecane, 1,
3-bromochloropropane, 1,4-dichlorobutane, 1,6-dichlorohexane, etc. can be used. Examples of organic polymers in which halogen atoms are directly bonded to aromatic nuclei include polystyrene or styrene.
Polymers based on divinylbenzene copolymers are commonly used, with brominated polystyrene being particularly preferred. Metallic lithium and α,ω-dihaloalkane are each 0.1 to 1 mole of halogenated organic polymer.
Preferably, it is provided in the range of 2 gram atoms, 0.1 to 1 mole. Further, the trialkylphosphine used in step (b) is represented by the general formula PR ¹ R ² R ³ and R ¹ , R ² , R ³
is methyl, ethyl, n-propyl, n-butyl,
A C ₁ to C ₈ n-alkyl group represented by n-octyl, or a C ₄ to _{C 8} alkyl group in which the carbon bonded to phosphorus is bonded to only one carbon, such as isobutyl, isopentyl, neopentyl, etc. ¹ , R ² and R ³ may all be the same or different. Specifically, trimethylphosphine, triethylphosphine, tri-
n-propylphosphine, tri-n-butylphosphine, tri-n-hexylphosphine, tri-
Examples include n-octylphosphine, dipropylbutylphosphine, triisobutylphosphine, triisopentylphosphine, triisohexylphosphine, triisooctylphosphine, and trineopentylphosphine. The above reaction is usually carried out at 50-180°C, preferably at 100°C.
It is carried out at ~150°C, and N,N-dimethylformamide, N-methylpyrrolidone, chlorobenzene, toluene, benzene, etc. are used as the solvent, but if the boiling point of phosphine is sufficiently high, the phosphine itself can be used as a solvent for several tens of minutes. - Heat for several hours. The obtained polymer beads are washed with methanol or the like, dried, and used as a catalyst. The catalyst obtained by the above method is used for the disproportionation and/or redistribution reaction of chlorosilane,
The disproportionation and/or redistribution reaction of chlorosilane may be carried out in the liquid phase or gas phase, and may be carried out in a flow or batch manner, but the gas phase is better because it can be carried out at lower pressure and the catalyst and products can be easily separated. is more preferable, and a flow type is preferable. The reaction temperature is 0 to 300°C, preferably 20 to 200°C, the pressure is normal pressure to 50 Kg/cm ² (gauge pressure), and the contact time is 0.01 to 20 seconds in a gas phase flow system.
It can be carried out in a liquid phase system for a period of 1 second to 20 minutes. The raw material chlorosilane is a chlorohydrogenated silane represented by SiHnCl _4-o (where 1≦n≦3). That is, one or two of monochlorosilane, dichlorosilane or trichlorosilane
A mixture of any composition of more than one type can be used, and may be diluted with an inert fluid such as nitrogen gas. Example 1 (1) Preparation of styrene-divinylbenzene copolymer beads with ω-bromo-n-hexylated aromatic nuclei. 10.7g of porous styrene-divinylbenzene copolymer beads with a bromine atom in the core, 0.42g of plate-shaped metallic lithium,
and 36 ml of ethyl ether were thoroughly replaced with nitrogen.
Pour into a 250ml four-necked flask and under nitrogen atmosphere.
Add 4.12 cc of 1,6-dibromohexane to 14 c.c. of ether with gentle stirring and make 20
It was added dropwise over a period of minutes. During this time, the flask was kept at 0° C. with ice water, and this temperature was maintained for 4 hours even after the dropwise addition, and then the temperature of the flask was raised to room temperature over 4 hours, followed by stirring at room temperature for 4 hours. While stirring gently, 10 ml of methanol was added to the flask to quench the reaction, and the beads were filtered and washed three times with methanol.
After air drying, the beads were dried in air at 100° C. to obtain styrene-divinylbenzene copolymer beads in which an ω-bromo-n-hexyl group was bonded to an aromatic nucleus. (2) Phosphonium formation reaction 7.2g of beads obtained in (1) above was added to 1.0ml of tri-n
-butylphosphine and 30 ml of N,N-dimethylformamide under nitrogen at 135 DEG C. for 3 hours. After filtering the beads, they were washed three times with methanol, air-dried, and then vacuum-dried at room temperature for 1 hour to produce styrene-divinylbenzene copolymer beads in which tri-n-butylphosphine was bonded to the aromatic nucleus via the hexamethylene group. I got it. The phosphorus content was 0.90% by weight. (3) Disproportionation reaction of trichlorosilane 10.5 mg of the polymer-bonded phosphonium salt beads obtained in (2) above were filled into a glass normal pressure flow reactor (inner diameter 5 mm) and heated at 120°C in a nitrogen stream for 1 hour.
After heating for a period of time, a disproportionation reaction was carried out under normal pressure while maintaining the reaction layer at a predetermined temperature using a mixed gas of SiHCl ₃ /H ₂ (molar ratio 3/7) as a feed. The product obtained 5 hours after setting the reaction conditions was analyzed using a gas chromatograph (TCD) using helium as a carrier gas. The results are shown in Table 1. The activity of the catalyst was determined by the values per catalyst active site (Kc) and per volume (Kv) using the following formula. Kc=lnCeq/Ceq-C・SV/N, Kc=lnCeq/Ceq-C・SV (Ceq: equilibrium conversion rate of trichlorosilane, C:
Measured conversion rate of trichlorosilane, SV: space velocity, N: concentration of phosphorus in catalyst: meq/ml) Example 2 (1) Styrene-divinylbenzene copolymer with aromatic nucleus ω-bromo-n-butylated Preparation of beads Brominated polystyrene 49 used in Example 1-(1)
g, 1.01 g of plate-shaped metallic lithium, and 200 ml of ethyl ether were placed in a four-necked flask (1) purged with nitrogen, and the flask was cooled to 0° C. with ice water.
While gently stirring the suspension of brominated polystyrene beads, a mixture of 11.0 ml of 1,4-dibromobutane and 20 ml of ethyl ether was slowly added dropwise into the flask over 30 minutes.
Stir overnight while cooling the flask to 0°C.
After confirming that no lithium metal remained after that time, the mixture was heated and refluxed for 3 hours. followed by 80
Quench the reaction by dropping ml of methanol,
After collecting the beads by filtration and washing them three times with methanol,
Air dried and then dried in air at 100°C. (2) Phosphoniumation reaction 10 g of the beads obtained in (1) above were heated with 1.0 ml of tri-n-butylphosphine and 30 ml of N,N-dimethylformamide at 135° C. under nitrogen for 3 hours. The subsequent processing is similar to (2) of the first embodiment. The phosphorus content by elemental analysis was 0.75% by weight. (3) Disproportionation reaction of trichlorosilane A disproportionation reaction of trichlorosilane was carried out in the same manner as in (3) of Example 1 using the phosphonium salt-bonded beads obtained in (2) above as a catalyst. The results are shown in Table 1. Comparative Example 1 Synthesis method using organolithium reagent and amine compound (1) Preparation of styrene-divinylbenzene copolymer beads with ω-bromohexylated aromatic nuclei Styrene-divinylbenzene copolymer beads
A mixture of 3.0 g (29 meq.), 29 mmol of n-butyllithium (in petroleum ether), 3.35 g (29 mmol) of tetramethylethylenediamine and 20 ml of cyclohexane was heated to 65°C and 20
Allowed time to react. The solution portion was removed from the resulting reaction mixture with a syringe and then washed twice with 10 ml of dry cyclohexane. 15.0 g of 1,6-dibromohexane (61
Add 50 ml of benzene solution (mmol) and incubate at room temperature.
Stirred for 10 hours. The beads were collected, washed twice with methanol and once with chloroform, and then dried to obtain ω-bromohexylated polystyrene beads. (2) Phosphonium formation reaction ω-bromohexylated polystyrene 1.0g,
0.4 ml of tri-n-butylphosphine and N,
Add a mixture of 5 ml of N-dimethylformamide to 140
The mixture was heated at ℃ for 24 hours to form a phosphonium. The beads were washed with methanol and chloroform to obtain phosphonated polystyrene beads. As a result of elemental analysis, the phosphorus content was 0.42% by weight (phosphorus bonded to 1.5% phenyl ring). (3) Disproportionation reaction of trichlorosilane A disproportionation reaction of trichlorosilane was carried out in the same manner as in (3) of Example 1 using the phosphonium salt-bonded beads obtained in (2) above as a catalyst. The results are shown in Table-1. Comparative Example 2 Synthesis method using brominated polystyrene and organolithium reagent (1) Preparation of styrene-divinylbenzene copolymer beads with ω-bromohexylated aromatic nuclei 5.0 g of brominated styrene-divinylbenzene copolymer beads (25 meq) n-butyllithium 25 mmol (hexane solution) and 20
ml of ether into the reaction flask and stir at room temperature for 30
Stir for 1 minute. The solution portion was removed with a syringe and the beads were washed with Eral. Thereafter, 5.7 ml of 1,6-dibromohexane was added, and the mixture was stirred at room temperature for 20 hours. The beads were collected, washed with methanol and chloroform, and dried. (2) Phosphonium formation reaction The ω-bromohexylated polystyrene obtained in (1) above and tri-n-butylphosphine are
The reaction was carried out in dimethylformamide to obtain phosphonated polystyrene beads. As a result of elemental analysis, the phosphorus content was 0.84% by weight. (3) Disproportionation reaction of trichlorosilane A disproportionation reaction of trichlorosilane was carried out according to the method (3) of Example 1 using the phosphonium salt-bonded beads obtained in (2) above as a catalyst. The results are shown in Table-1.

[Table] Effects of the invention (1) The lithiation step using an organolithium reagent and the ω-haloalkylation step using an α,ω-dihaloalkane are combined, and the operation is simplified because metallic lithium is used. . (2) Highly safe because highly stable metallic lithium is used without using highly reactive organolithium reagents. (3) Organolithium reagents are significantly more expensive than metallic lithium, and this synthesis method is much more economical than conventional methods.

Claims (1)

[Claims] 1. An organic polymer compound in which a halogen atom is directly bonded to an aromatic nucleus is prepared in a solvent using metallic lithium and the general formula X-(CH ₂ -) _o X' the same or different halogen atoms, and n represents a number from 2 to 10] to obtain an organic polymer compound in which the aromatic nucleus is ω-haloalkylated by contacting with an α,ω-dihaloalkane; , a chlorosilane disproportionate compound in which a tetraalkylphosphonium salt having a methylene group as a crosslinking group is bonded to an organic polymer, characterized by comprising a step (b) of reacting an ω-haloalkylated organic polymer compound with a trialkylphosphine. A method for producing a catalyst for chemical reaction and/or redistribution reaction.