JPS6336840A - Production of chlorosilane disproportionation catalyst - Google Patents

Abstract

PURPOSE:To simplify the reaction operation and to enhance the stability of the title catalyst by allowing an omega-haloalkylated org. high molecular compd. to react with trialkylphosphine to form the chlorosilane disproportionation catalyst. CONSTITUTION:The org. high molecular compd. wherein a halogen atom is directly bonded to an aromatic nucleus is brought into contact with metal lithium and alpha,omega-dihaloalkane expressed by formula I in a solvent, and the aromatic nucleus is omega-haloalkylated [X and X' are halogen atoms and (n) stands for 2-10 integer]. The omega-haloalkylated org. high molecular compd. is then allowed to react with trialkylphosphine to produce a chlorosilane disproportionation and/or redistribution catalyst wherein a tetraalkylphosphonium salt having a methylene group as the cross-linking group combines with an org. macromolecule.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to the production of silanes by disproportionation and/or redistribution reactions of chlorohydrogenated silanes, and in particular to methods for producing catalysts useful for such reactions.

Conventional technology Conventionally, quaternary phosphonium salts bonded to organic polymers are of the type in which a phosphorus atom is directly bonded to an aromatic nucleus (phenyl type) or in which a halogen atom is bonded to an aromatic nucleus via one methylene atom. The bonded type (benzyl type) is -
It was inside the shell. 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 dimethylene'Is (-CHxCHx-) or more, and the remaining bonding group of the phosphorus atom is primary alkyl, this phosphonium salt will be very stable. Having discovered this, the inventors of the present invention filed a patent application (Japanese Patent Application No. 210325/1986).
issue).

To synthesize phosphonium salts with such structures, conventional methods use combinations of polystyrene, tetramethylethylenediamine, organolithium reagents, dihaloalkanes, and trialkylphosphines, or brominated polystyrene, organolithium reagents, dihaloalkanes, and They were synthesized using trialkylphosphines as raw materials, but these methods had the disadvantage that the organolithium reagents were expensive and dangerous to handle.

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-mentioned problems, the present inventors conducted extensive research and completed the present invention by finding a synthetic route using metallic lithium, which is safer and cheaper than IJ thium.

That is, in the present invention, seven halogen atoms are directly bonded to the aromatic nucleus. a halogen atom 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 represented by Step (1) of reacting a haloalkylated organic polymer with trialkylphosphine
-fCHt+(
The present invention relates to a method for producing a chlorosilane disproportionation reaction catalyst to which a tetraalkylphosphonium salt having a methylene group (n=2 to 10) as an ai stripe 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 α,ω-di...roalkane, which then reacts with metallic lithium again. Then, producing an organolithium reagent and lithiation of the brominated polystyrene is repeated until metallic lithium is consumed.

Thereafter, the lithiated aromatic nucleus reacts with this 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. The reaction temperature is preferably 0 to 40°C.

The α,ω-dihaloalkane represented by the above general formula includes 1,2-dibromoethane, 1,3-dibromopropane, 1. a-dichlorobutane, 1.5=cyfuromobentane, 1.6-dichlorohexane, 1.7-dibromohebutane, 1.8-dibromooctane, 1,1o-dibromodecane, 1.5-7' cyclopropane, 1,4-dichlorobutane, 1,6-dichlorohexane, etc. can be used.

As the organic polymer in which a halogen atom is directly bonded to an aromatic nucleus, polystyrene or a styrene-divinylbenzene copolymer is usually used, and brominated polystyrene is particularly preferably used.

It is preferable that metallic lithium and α,ω-dihaloalkane be supplied in an amount of 0.1 to 2 gram atoms and 0.1 to 1 mole, respectively, per mole of the halogenated organic polymer.

Further, the trialkylphosphine used in step (b) is represented by the general formula P R'R''R' and R1, E
(I.

R3 is methyl, ethyl, n-propyl, n-butyl, n
~C1~CB n-alkyl group represented by octyl etc. or 04~C where the carbon bonded to phosphorus is bonded to only one carbon such as isobutyl, impentyl, neopentyl etc.
In the alkyl group of s, R1°R2 and R3 may all be the same or different. Specifically, trimethylphosphine, triethylphosphine, tri-n-propylphosphine,
Tri-n-butylphosphine, tri-n-hexylphosphine, tri-n-octylphosphine, diglobylbutylphosphine, triisobutylphosphine, triisopentylphosphine, triynehexylphosphine, triineoctylphosphine, trineopentylphosphine, etc. It will be done.

The above reaction is usually carried out at 50 to 180°C, preferably at 100°C.
It is carried out at ~150°C, and as a solvent, N,N-dimethylformamide, N-methylpyrrolidone, chlorobenzene, toluene, benzene, etc. are used, but if the boiling point of phosphine is sufficiently high, the phosphine itself can be used as a solvent.
This is done by heating for 0 minutes to 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. Alternatively, a batch method may be used, but a gas phase is preferable because it can be carried out at low pressure and the catalyst and products can be easily separated, and a flow method is preferable. The reaction temperature is 0-500℃,
Preferably the temperature is 20 to 200°C, and the pressure is normal pressure to 50°C.
kg/c,? (gauge pressure) and the contact time can be in the range of 0.01 to 20 seconds in a gas phase flow system, and in the range of 1 second to 20 minutes in a liquid phase system.

In other words, the raw material chlorosilane is a chlorohydrogenated silane represented by 5iHnC24-n (where 1≦n≦3). That is, one type or a mixture of two or more of monochlorosilane, dichlorosilane, and trichlorosilane with any composition can be used, and the mixture may be diluted with an inert fluid such as nitrogen gas.

Example 1 1) Preparation of styrene-divinylbenzene copolymer beads with ω-promo-n-hexylated aromatic nuclei Known method (Example of JP-A-58-80307)
Porous styrene-divinylbenzene copolymer beads 1α72 having a bromine atom in the aromatic nucleus prepared according to 1)
, plate-shaped gold m IJ thium α42? , and 36- ethyl ether were placed in a 250-metre four-bottle flask that had been well purged with nitrogen, and the ethyl ether of 412-
A mixture of CH1,6-dibromohexane and 14CH ether was added dropwise over 20 minutes. During this time, the flask was kept at 0°C with ice water, and this temperature was maintained for 4 hours after the addition, and then the flask was brought to room temperature for 4 hours.
Then, the mixture was stirred at room temperature for 4 hours. While stirring slowly, 10-methanol was added to the flask to quench the reaction, and the beads were collected by filtration 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-promo n-hexyl group was bonded to the aromatic nucleus.

2) Phosphonium formation reaction Beads 7 and 29 obtained in 1) above were treated with 1.0-IJ-
It was heated with n-butylphosphine and 50-0N,N-dimethylformamide at 135°C under nitrogen for 5 hours. After filtering the beads, they were washed three times with methanol, air-dried, and vacuum-dried at room temperature for 1 hour.
Divinylbenzene copolymer heath (P s t (■C
Hz %P (n-B u )s m Br was obtained. The phosphorus content was 190% by weight.

3) Trichlorosilane disproportionation reaction Polymer-bonded phosphonium salt beads 1 obtained in 2) above
cL5rNi was heated in a glass-backed normal pressure flow reactor (inner diameter 5
mm), heated at 120°C for 1 hour in a nitrogen stream, and then heated to S 1Hct under normal pressure while keeping the reaction layer at a predetermined temperature.
The disproportionation reaction was carried out using a mixed gas of s/Hz (molar ratio 3/7) as 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 using the following formula to determine the values per catalyst active site (Kc) and per volume (Kv).

Ceq -CN Ceq -C (Ceq: equilibrium conversion rate of trichlorosilane, actual temperature conversion rate of C nitrichlorosilane, Sv: space velocity, N: concentration of phosphorus in catalyst: meq/+
++j) Example 2 1) Styrene with aromatic nucleus ω-promo n-butylated
Preparation of divinylbenzene copolymer beads Brominated polystyrene 49? used in Example 1-1) , plate-shaped metallic lithium 1.01 ? , 200 m of ethyl ether was placed in a 1 t four-bottle flask purged with nitrogen, and the flask was cooled to 0°C with ice water. Gently stir the suspension of brominated polystyrene beads.

A mixture of 11, Od of 1,4-dibromobutane and 20-od of ethyl ether was slowly added dropwise to the reflux over 30 minutes. Flask.

The mixture was stirred overnight while being cooled to <RTIgt;C.</RTI> After 12 hours, it was confirmed that no lithium metal remained, and then heated for 3 hours to reflux. Subsequently, 80 ml of methanol was added dropwise to quench the reaction, and the beads were collected by filtration, washed three times with methanol, air-dried, and then dried in air at 100°C.

2) Phosphonium formation reaction Among the beads obtained in 1) above, 10 r'i 1.0- of tri-n-butylphosphine and 304 of N,N-dimethylformamide were heated under nitrogen at 135° C. for 5 hours.

The subsequent processing is similar to 2) of Example 1. The phosphorus content by elemental analysis was α75%.

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 aban compound 1) Aromatic [-ω-bromohexylated styrene-
Preparation of divinylbenzene copolymer beads Styrene-divinylbenzene copolymer beads 50? (29 milliequivalent),
29 moles of n-butyllithium (petroleum ether solution)
, a mixture of tetramethylethylenediamine & 35F (29 mmol) and cyclohexane 2CIW#t.
℃ and allowed to react for 20 hours.

The solution portion was removed from the resulting reaction mixture with a syringe and then washed twice with dry cyclohexane 10-. Add 1,6-dipromohexane 15. to the obtained brown beads.
A 50-solution of 0f (61 < mol) in benzene was added, and the mixture was stirred at room temperature for 10 hours. Take the beads, wash them twice with methanol and once with chloroform, and then invert them to obtain ω-
Bromohexylated polystyrene beads were obtained.

2) Phosphonium formation reaction ω-bromohexylated polystyrene 1.01, trin
- heating a mixture of butylphosphine 0.4- and N,N-dimethylformamide 5- at 140°C for 24 hours,
Phosphoniumated. After washing with methanol and chloroform, phosphonated polystyrene beads were obtained.

As a result of elemental analysis, the phosphorus content was [1,42% (1,
5% of the phenyl ring was phosphorus bonded).

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) tPJ mJX m of styrene-divinylbenzene copolymer beads with ω-bromohexylated aromatic nuclei 5.
Of (25 meq.) n-butyllithium 25 (limol (hexane solution)) and ether of 20- were placed in a reaction flask and stirred for 50 minutes at room temperature. The solution portion was removed with a syringe and the beads were washed with ether.

Then, 5.7-dibromohexane was added, and the mixture was stirred at room temperature for 20 hours. Take the beads, add methanol,
The solution was washed with O2 roform and dried.

2) Phosphonium formation reaction ω-bromohexylated poly, X, f obtained in 1) above
Lentto IJ -n-Butylphosphine was reacted in N,N-dimethylformamide to obtain phosphonated polystyrene beads. As a result of elemental analysis, the content of Shin is 1
The overlap was 84%.

3) Disproportionation reaction of trichlorosilane A disproportionation reaction of trichlorosilane was carried out by the method described in 5) of Example 1 using the phosphonium salt-bonded beads obtained in 2) above as a catalyst. The results are shown in Table-1.

Table-1 Effects of the invention 1) Lithiation step using organolithium reagent and α,
The operation is simple because it is combined with the ω-haloalkylation step using #-dihaloalkane and uses gold and V4 lithium.

2) It is highly safe because highly stable metallic lithium is used without using a highly reactive organolithium reagent.

3) Organolithium reagents are significantly more expensive than metallic lithium, and this synthesis is much more economical than conventional methods.

Claims (1)

[Claims] An organic polymer compound in which a halogen atom is directly bonded to an aromatic nucleus is prepared in a solvent by metallic lithium and general formula X-(ch_2
)-_nX' [where X and X' represent the same or different halogen atoms, and n represents a number from 2 to 10] to contact with α,ω-dihaloalkane to ω-haloalkylate the aromatic nucleus. a step (a) of obtaining an organic polymer compound which has been subjected to A method for producing a catalyst for a chlorosilane disproportionation reaction and/or redistribution reaction having a tetraalkylphosphonium salt bonded thereto.