JP3452598B2 - Method for producing triisocyanatosilane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel process for producing triisocyanatosilane (hereinafter abbreviated as TIS).

[0002]

2. Description of the Related Art The TIS obtained by the present invention is extremely reactive in chemical structure, and is used for surface modification of inorganic materials, surface modification of organic materials, crosslinking, adhesion, reaction reagents for organic synthesis, coupling agents, etc. It is expected to be used for

[0003] In addition to the conventional method of producing TIS, trichlorosilane and silver cyanate are reacted in an organic solvent, and trichlorosilane and sodium cyanate are reacted in a high boiling organic solvent using 18-crown-6 as a catalyst. A method of causing this is reported in U.S. Pat. No. 4,176,131 (published December 4, 1978).

[0004]

TIS, unlike other isocyanatosilanes, has very few examples of synthesis. Method of reacting silver cyanate with chlorosilane as raw material (V.
P. Kozyukov, VDSheludyakov, and VFMironov, Rus
s. Chem. Rev., 42 (8) , 662, (1973)) is effective as a means for synthesizing other isocyanatosilanes.
In the case of (1), since the Si—H bond is reducible, an oxidation-reduction reaction occurs with silver cyanate, silver is precipitated, and tetraisocyanatosilane (62%) is generated.

2HSiCl ₃ + 8AgOCN → 2Si (NCO) ₄ + 6AgCl + 2Ag + H ₂ (1) As a result, TIS can be obtained only in a yield of 15% (F.
Hoefler, G. Jaegerhuber, W. Veigl, Monatsh. Chem., 10
5 (3) , 539, (1974)). When triiodosilane, which is more reactive than trichlorosilane, is used as a raw material, T
The synthesis yield of IS is 25%. However, triiodosilane is expensive and uncommon as a general-purpose raw material, and thus is not suitable for industrialization. As another synthesis method, there is a method in which trichlorosilane and sodium cyanate are reacted in a high boiling point solvent using 18-crown-6 as a catalyst. At the same time, 20.4% of unreacted trichlorosilane is recovered (US Patent, 4176131, (1979)).

However, in any of these methods, T
Since the synthesis yield of IS is low and the raw materials are expensive, it has been difficult to industrially produce TIS.

On the other hand, F. Hofler et al. Tried to synthesize TIS by reacting trichlorosilane and potassium cyanate in acetonitrile (F. Hoefler, G. Jaegerhuber, W. et al.
Veigl, Monatsh. Chem., 105 (3) , 539, (1974)), but includes SiCl ₄ , H ₂ SiCl ₂ , and H ₃ SiC.
It is reported that a disproportionation reaction for producing 1, SiH ₄ is likely to occur, and that trichlorosilane as a raw material is consumed, so that TIS cannot be obtained and only tetraisocyanatosilane can be obtained in a low yield. Further, according to this report, the anion of isocyanate present in the reaction system promotes this disproportionation reaction.

On the other hand, even when only acetonitrile is used as a solvent, TIS can be obtained with a yield of 52%. However, since acetonitrile disperses the inorganic salt well, it is very difficult to separate the solid by filtration. Further, depending on the reaction scale (using 271 g (2.0 mol) of trichlorosilane), the above-mentioned disproportionation reaction is easily induced, This is not suitable as a synthesis condition because the yield of TIS may be remarkably reduced.

However, the present inventors have paid attention to acetonitrile having extremely high polarity among organic solvents. That is, acetonitrile has a high polarity (dielectric constant 3).
7.5 (20 ° C.), dipole moment 3.44 D (20
° C, benzene)), the effect of promoting the dissociation of inorganic salts can be expected. In addition, since it is an aprotic organic solvent that does not react with the raw material toluchlorosilane, it is considered that it is most suitable as a solvent or additive at the time of TIS synthesis.

Thus, the present invention uses trichlorosilane and alkali cyanate, which are inexpensive as compared with the silver cyanate and the like, as raw materials, and can suppress the promotion of the disproportionation reaction due to the isocyanate in the presence of acetonitrile. It is an object of the present invention to provide a method for producing triisocyanate silane in high yield by reacting both under reaction conditions.

[0011]

Accordingly, the present invention provides a method for producing triisocyanatosilane by reacting trichlorosilane and alkali cyanate, wherein the reaction is carried out in an organic solvent containing a small amount of acetonitrile. And a method for producing triisocyanatosilane.

That is, according to the present invention, an organic solvent in which acetonitrile is mixed at an appropriate ratio is used as a reaction solvent, and an alkali cyanate such as sodium or potassium cyanate is dispersed therein, and trichlorosilane is added to the mixture at room temperature. The TIS is synthesized by dropping and reacting.

As the organic solvent used together with acetonitrile in the present invention, a nonpolar solvent such as benzene, toluene and xylene which does not participate in the dissociation of sodium cyanate is particularly suitable. This is not restrictive as long as it is a protic organic solvent, and other organic solvents can be used as a reaction solvent together with acetonitrile.

The present invention does not require expensive reaction reagents such as silver cyanate or 18-crown-6 as in the conventional synthesis method, and is a relatively easily available sodium cyanate industrially produced. It is economical because it uses acetonitrile and acetonitrile.

About 3 vol% of acetonitrile used in the present invention is sufficient with respect to the total amount of the reaction solvent. If the content of acetonitrile in the reaction solvent is smaller than this, the reaction does not proceed sufficiently, and a large amount of trichlorosilane is recovered as an unreacted substance. On the other hand, when the content of acetonitrile exceeds 3%, the disproportionation reaction tends to be promoted as the content of acetonitrile increases, and the synthesis yield of TIS is remarkably reduced, and the by-product of tetraisocyanatosilane is produced. The amount increases. Thus, the content of acetonitrile is about 2-4.
The range of volume% is preferred, so that the triisocyanatosilane can be obtained with a yield of 60 to 70%.

A reaction time of about 3 hours after the completion of the dropwise addition of trichlorosilane is sufficient. The reaction temperature is 58 to 80 according to the conventional method using silver cyanate or 18-crown-6.
While the temperature is relatively high at about ° C, the temperature of the present invention using acetonitrile may be about 35 ° C, and TIS synthesis at room temperature is also possible. Furthermore, the TIS obtained in the present invention can be easily isolated by distillation under reduced pressure using a rectification tube, and the TIS obtained as a fraction has been confirmed by gas chromatography to have a purity of 97% or more.

[0017]

【Example】

Example 1 Synthesis of Triisocyanatosilane Using Acetonitrile as Solvent or Additive A 200-ml four-necked flask equipped with a mechanical stirrer, a condenser and a dropping funnel was purged with nitrogen after purging the reaction system with nitrogen. 8 dried under reduced pressure in a one-necked flask
34.4 g (0.45 mol) of 5% sodium cyanate, 3
100 ml of a vol% acetonitrile-benzene solution was charged and kept at 20 ° C. Next, 20.3 g (0.15 mol) of trichlorosilane and 20 ml of a 3 vol% acetonitrile-benzene solution were added to the dropping funnel and dropped.
After completion of the dropwise addition, the mixture was stirred for 3 hours while maintaining the temperature at 35 ° C. After removing the solid by filtration, the unreacted substances and the solvent were removed under reduced pressure.
Distillation was performed under reduced pressure to obtain 16.6 g (70.1%) of TIS (b.
p. 65.0-66.0 / 28 [° C / mmHg]).

The same experiment was conducted by changing the mixing ratio of acetonitrile-benzene, and the results are shown in Table 1 and FIG. Example 2 Synthesis of Triisocyanatosilane Using Only Acetonitrile as a Solvent A mechanical stirrer, a condenser and a dropping funnel were attached to a 200-ml four-necked flask, and the inside of the reaction system was replaced with nitrogen. 8 dried in a flask under reduced pressure
34.4 g of 5% sodium cyanate (0.45 mol
l), 100 ml of acetonitrile was charged, and this was kept at 20 ° C. Next, trichlorosilane was added to the dropping funnel.
3 g (0.15 mol) and 20 ml of acetonitrile were added and added dropwise. After completion of the dropwise addition, the mixture was stirred for 3 hours while maintaining the temperature at 35 ° C. After adding 100 ml of benzene to suppress dispersion of the inorganic salt and facilitate filtration of the solid, the solid was filtered off. The unreacted substances and the solvent were removed under reduced pressure, and distilled under reduced pressure to obtain 12.5 g (52.6%) of TIS (bp 58.4).
-59.5 / 19 [° C / mmHg]). The results are shown in Table 1 and FIG.

Table 1 Production of TIS ^a) Capacity fraction distillate product, yield _{g (%) CH 3 CN (} vol%) HSi (NCO) 3 Si (NCO) 4 100 12.5 (52.6) 1.4 (0.6) 95 10.1 (42.8) 3.0 (9.0) 80 2.6 (10.4) 9.4 (28.0) ) 60 3.6 (13.8) 10.3 (30.0) 50 4.3 (16.6) 9.9 (29.4) 40 6.2 (25.7) 7.7 (23. 7) 30 7.6 (30.5) 6.4 (17.9) 20 8.0 (32.1) 5.3 (14.4) 10 10.2 (42.9) 3.7 (9) .6) 5 14.3 (56.7) 1.4 (1.1) 4 15.2 (63.1) ^b) 3 16.6 (70.1) ... ……… ^b) 2 14.8 (61.6) …………… ^b) 1 2.6 (10.3) …………… ^b) 0 ……………… … ^B) ………………… ^b) a) HSiCl ₃ used: 20.3 g (0.15 mol). b) Without separation, the content of acetonitrile was 3 vol% as shown in Table 1.
As a result, TIS was obtained with the highest purification yield (70%), and this was the optimal condition for the synthesis of TIS.

Comparative Example 1 Synthesis of Triisocyanatosilane Using 18-Crown-6 as a Catalyst A mechanical stirrer, a condenser, and a dropping funnel were attached to a 200-ml four-necked flask, and the inside of the reaction system was purged with nitrogen. After drying under reduced pressure in a four-necked flask, 8
34.4 g of 5% sodium cyanate (0.45 mol
l), 18-crown-6 0.5 g (1.9 × 10 ⁻³⁾
mol) and 100 ml of diethyl ether.
It was kept at 0 ° C. Next, 20.3 g (0.15 mol) of trichlorosilane and diethyl ether 20 were added to the dropping funnel.
ml was added and added dropwise. After completion of the dropwise addition, the mixture was stirred for 3 hours while maintaining the temperature at 35 ° C. After the solid was separated by filtration, the unreacted substances and the solvent were removed under reduced pressure, followed by distillation under reduced pressure to obtain a product. The results are shown in Table 2, and the yield was lower than when the method of the present invention was used.

Table 2 Production of TIS ^a) Distillate, yield g (%) Solvent additive HSi (NCO) ₃ Si (NCO) ₄ Et ₂ O 18-crown-6 6.2 (24.5) 6.6 (21.5) a) HSiCl ₃ used: 20.3 g (0.15 mol).

[Brief description of the drawings]

FIG. 1 is a graph plotting the relationship between the content of acetonitrile obtained in Examples-1 and 2 and the purification yield of isocyanatosilane.

────────────────────────────────────────────────── (5) References US Patent No. 4176131 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07F 7/10

Claims (1)

(57) [Claims] 1. A process for producing triisocyanatosilane by reacting trichlorosilane and alkali cyanate, wherein the reaction is carried out in an organic solvent containing a small amount of acetonitrile. .