JPH05320179A - Hydrolysis of organochlorosilane - Google Patents

Abstract

PURPOSE:To obtain a polyorganosiloxane by hydrolysis of an organochlorosilane with industrial advantage wherein the first step of the hydrolysis is carried out in a hydrogen chloride-saturated alcohol and the subsequent step, in a dilute hydrogen chloride solution. CONSTITUTION:The first step of hydrolysis of an organochlorosilane is carried out in an alcohol, preferably 10 to 35wt.% (based on the organosilane) of methanol at 30 to 60 deg.C under the hydrogen chloride saturated conditions until the hydrolyzate reaches 20 to 40% based on the whole reaction system, then the second step is performed in a diluted hydrogen chloride solution (preferably less than 20% hydrogen chloride concentration) at a temperature lower than 40 deg.C. The objective polyorganosiloxane is obtained by these continuous step of hydrolysis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for hydrolyzing organochlorosilane used to obtain polyorganosiloxane used as a raw material for silicone resins such as silicone rubber, silicone oil and silicone varnish.

[0002]

2. Description of the Related Art The basic raw material chemical structure of silicones such as silicone rubber, silicone oil and silicone varnish is polydimethylsiloxane.
As a method of industrially obtaining this polydimethylsiloxane, a method of continuously hydrolyzing dimethyldichlorosilane is adopted. In this reaction, dimethyldichlorosilane is brought into contact with water to obtain a trimer to octamer cyclic polydimethylsiloxane or a linear polydimethylsiloxane having a silanol at the molecular chain end.

Such hydrolysis methods include a method of using a large excess of water and a method of using an equivalent amount of water. Although there are merits and demerits in each method, the method of using an equivalent amount of water is industrially preferable. It is advantageous. That is, it is difficult to collect the dilute hydrochloric acid by-produced by the method using a large excess of water, whereas the method using an equivalent amount of water produces hydrochloric acid in a gaseous state and can be easily recovered. ..

However, the method using an equivalent amount of water has a problem that the amount of dissolved hydrogen chloride in the obtained hydrolysis product is high and the neutralization for producing the product requires a cost.

Therefore, a method has been proposed in which the hydrolysis is carried out in two steps (JP-A-2-8223). In this method, the first step is hydrolyzed using substantially stoichiometrically equivalent amount of water. After the hydrochloric acid is recovered, the hydrolysis is completed at a relatively low temperature in the second step using a stoichiometrically excessive amount of hydrogen chloride aqueous solution. According to this method, it is said that the polyorganosiloxane having a desired viscosity can be obtained by efficiently hydrolyzing and recovering hydrogen chloride.

[0006]

However, the above-mentioned 2
The stepwise hydrolysis method is as follows.
Since the reaction solution is always saturated with hydrogen chloride,
In addition to cyclic polyorganosiloxanes and linear polyorganosiloxanes having silanol at the ends, by-products of linear polyorganosiloxanes having chloro atoms at the ends cannot be avoided as hydrolysis products. This linear polyorganosiloxane having a chloro atom at the terminal undergoes further condensation reaction with the linear polyorganosiloxane having a silanol at the terminal, or the ring-opening polymerization with the cyclic polyorganosiloxane proceeds, which is sometimes handled. It becomes a high viscosity product that is difficult to Therefore, there is a problem that it becomes difficult to separate the polyorganosiloxane and the aqueous solution in the liquid / liquid phase separator after the reaction.

The present invention has been made to improve the above circumstances, and an object of the present invention is to provide a method for hydrolyzing an organochlorosilane capable of industrially producing a polyorganosiloxane.

[0008]

Means and Actions for Solving the Problems As a result of intensive studies to achieve the above-mentioned object, the present inventor hydrolyzed organochlorosilane in the presence of alcohol first.
It has been found that it is effective to carry out the reaction in a saturated hydrogen chloride aqueous solution, and then to perform the second stage hydrolysis of the hydrolyzate of the organochlorosilane in a dilute hydrogen chloride aqueous solution.

That is, by carrying out the hydrolysis of the organochlorosilane in the first step in the presence of alcohol, it is possible to suppress the production of a linear polyorganosiloxane having a chloro atom at the terminal of the molecular chain, and at the same time, to develop the organochlorosilane. Since the production amount of cyclic polyorganosiloxane in the hydrolyzate can be increased, the viscosity of the resulting organochlorosilane hydrolysis product can be reduced, and the second-stage hydrolysis can be performed in a dilute aqueous hydrogen chloride solution. It was found by carrying out the method that the separation from the aqueous phase in the steps after the respective hydrolysis (first step, second step) is facilitated, and the polyorganosiloxane can be industrially produced advantageously, and the present invention It was the eggplant.

Therefore, the present invention is a method for producing a polyorganosiloxane by hydrolyzing an organochlorosilane, wherein the first stage hydrolysis is carried out in a saturated hydrogen chloride solution in the presence of alcohol, and the second stage hydrolysis is carried out. Provided is a method for hydrolyzing organochlorosilane, which is characterized in that it is carried out in a dilute hydrogen chloride solution.

Here, as the starting organochlorosilane to be used, one represented by the following formula (1) can be used.

R _n SiX _4-n (1)

In this formula, R is a hydrogen atom or has 1 to 6 carbon atoms.
And a hydrocarbon group such as an alkyl group such as a methyl group, an ethyl group and a propyl group, and an aryl group such as a phenyl group. n is an integer of 1 to 3, and when n is 2 or more, Rs may be the same or different. Further, X is a chloro atom or an alkoxy group, but at least one of X is a chloro atom. Therefore, the chlorosilane that can be used may be a mixture of chlorosilane and alkoxysilane. Of these, dimethyldichlorosilane is particularly preferable.

Further, a polyorganosiloxane represented by the following formula (2) may be mixed with the organochlorosilane represented by the above formula (1).

R _a X _b SiO _{(4-ab) / 2} (2) (wherein R and X have the same meanings as described above, and a and b
Is a positive number and 0 <a + b <4. )

The first stage reaction of the hydrolysis of the organochlorosilane of the present invention is carried out in the presence of alcohol as described above.
It is carried out in a saturated hydrogen chloride solution.

In this case, the hydrolysis reaction temperature is generally 10 to 65 ° C. The level of the first-stage reaction temperature affects the saturated hydrogen chloride concentration, and the saturated hydrogen chloride concentration increases as the temperature decreases. The saturated hydrogen chloride concentration in the temperature range of 10 to 65 ° C is uniquely determined by the temperature,
It is 34% by weight. Therefore, when the reaction temperature rises, the amount of the linear polyorganosiloxane having a chloro atom at the terminal decreases, but since the reaction temperature is high, ring-opening polymerization of the cyclic polyorganosiloxane occurs. Since the condensation of the linear polyorganosiloxanes proceeds more at high temperature, the viscosity becomes higher. The opposite occurs when the reaction temperature is low.

If the reaction temperature is higher than 65 ° C., the amount of unreacted raw material entrained in the anhydrous hydrogen chloride gas discharged from the reaction system may increase, and the yield may decrease. On the other hand, when the reaction temperature is lower than 10 ° C., the viscosity of the organochlorosilane hydrolyzate is low, but the viscosity difference between the hydrolysis reaction step and the neutralization reaction step becomes too large, and after the neutralization step, Phase separation may become difficult. For this reason,
The first-stage hydrolysis reaction temperature in the present invention is particularly 30 to
60 ° C is preferred.

In the first-stage hydrolysis reaction, the ratio of the organochlorosilane hydrolysis product produced to the saturated hydrogen chloride solution phase in the reactor (concentration of the hydrolyzate in the reaction system, that is, used for hydrolysis) Relative ratio with water) has a great effect on productivity. That is, the higher the concentration of the organochlorosilane hydrolyzate, the higher the productivity. Further, when the effect of the concentration of the organochlorosilane hydrolyzate in the reactor for the first-stage hydrolysis reaction on the viscosity of the hydrolysis product is examined, the viscosity of the product increases as the organochlorosilane hydrolyzate concentration increases. Show a trend. On the other hand, if the organochlorosilane hydrolyzate concentration is too high, the probability that a sufficient amount of water and organochlorosilane will contact decreases, and unreacted organochlorosilane or low molecular weight organochlorosilane hydrolyzate that evaporates from the reactor along with hydrogen chloride gas And the amount of product decreases. On the other hand, the amount of the saturated hydrogen chloride aqueous solution can be increased if necessary, but the lower the organochlorosilane hydrolyzate concentration, the lower the productivity. Therefore, the organochlorosilane hydrolyzate concentration is 15-7.
A range of 0% by weight, particularly 20 to 40% by weight is preferable.

In the present invention, the first stage hydrolysis reaction is carried out in the presence of alcohol. In this case, the alcohol is preferably an aliphatic monohydric alcohol, for example, methyl alcohol or ethyl alcohol. ,
Propyl alcohol, butyl alcohol, pentyl alcohol, hexyl alcohol and the like can be mentioned. Of these, methanol is particularly preferable.

The amount of alcohol added is not particularly limited, but depends on the molar amount of organochlorosilane used for hydrolysis. The greater the amount of alcohol, the greater the amount of linear polyorganosiloxane terminated with an alkoxy group and the lower the viscosity. In this case, if the amount of the linear terminal alkoxypolyorganosiloxane is large, the hydrolysis reaction product is not used as it is as a raw material in the next step to obtain a cyclic polyorganosiloxane, which adversely affects the alkali cracking reaction. Sometimes,
A large amount of alcohol may be added to a product which may have an alkoxy group at the terminal. On the other hand, if a large amount of alcohol is added, the cost naturally increases, so that the amount used may be limited in terms of product price. Therefore, the amount of alcohol is generally relative to organochlorosilane,
It is preferably 5 to 70% by weight, and economically 10 to 35% by weight.

Further, in the present invention, it is optional to use other solvent in addition to alcohol, for example, an inert solvent such as toluene, benzene, acetone, ether, carbon tetrachloride, trichloroethylene, etc. may be used. it can. When a solvent other than alcohol is used for the production of polyorganosiloxane, which is the main raw material in the silicone industry, like polydimethylorganosiloxane, which is usually obtained by the continuous hydrolysis reaction of dimethyldichlorosilane, these solvents must be removed after the reaction. Although it is uneconomical to use, it is effective to use a solvent other than alcohol when hydrolyzing a silane containing a T unit such as trimethylchlorosilane. The amount of the solvent other than these alcohols used is generally 50% by weight or less based on the organochlorosilane hydrolyzate.

The residence time of the organochlorosilane hydrolysis product in the reactor for the first stage hydrolysis reaction is preferably about 4 to 60 minutes in operation.

In the method for hydrolyzing the organochlorosilane of the present invention, after the above-mentioned first stage hydrolysis, a second stage hydrolysis reaction is further carried out using a dilute hydrogen chloride solution. The purpose is to complement the first-stage hydrolysis reaction to complete 100% hydrolysis and to improve the chlorine recovery efficiency.

If the concentration of the dilute hydrogen chloride solution used in the second-step hydrolysis reaction is too high, the cyclic polysiloxane will undergo ring-opening polymerization to increase the viscosity, so the concentration is preferably 20% by weight or less, and particularly preferably 20% by weight or less. It is economical to use a 5-20 wt% dilute hydrogen chloride solution that is industrially easy and available at low cost. In particular, it is most economical to use the residual solution prepared by synthesizing methyl chloride by the reaction of methanol and hydrogen chloride as the dilute hydrogen chloride solution. In other words, the recovery of chlorine in the residual solution (dilute hydrogen chloride aqueous solution), which is a by-product of methyl chloride synthesis, has been thrown away because it was industrially (economically) impossible until now, but it can be effectively used. Is extremely advantageous to the industry. Note that alcohol can be added to this dilute hydrogen chloride solution as in the first-step hydrolysis reaction.

The reaction temperature of the second-stage hydrolysis reaction is not particularly limited, but if both the hydrogen chloride concentration and the reaction temperature are high, the ring-opening polymerization of the cyclic polyorganosiloxane will proceed. It is preferable that the concentration is 20% by weight or less and the reaction temperature is 40 ° C or less. Further, the higher the organochlorosilane hydrolyzate (first stage hydrolyzate) concentration is, the more excellent the productivity is, and the range of generally 40 to 80% by weight, particularly 50 to 70% by weight is preferable. In addition,
Since the ring-opening polymerization reaction proceeds as the residence time becomes longer, it is preferable that the residence time be as short as possible, and usually 60 minutes or less is preferable in order to avoid the influence of an increase in viscosity.

The organochlorosilane hydrolysis product that has undergone the second stage hydrolysis reaction can be neutralized and washed with water to obtain a product. Here, a problem in the neutralization reaction is the presence of a linear polyorganosiloxane having a chloro atom at the terminal, which is contained in the organochlorosilane hydrolysis product before the neutralization. If the amount of the linear polyorganosiloxane having chloro atoms at the end is large, a high-molecular-weight linear polyorganosiloxane is produced by the neutralization reaction, and the product becomes a highly viscous product, resulting in extremely poor separation from the aqueous phase. According to the two-step hydrolysis reaction of the present invention, the amount of the linear polyorganosiloxane having a chloro atom at the end is extremely small before the neutralization reaction,
Since it is possible to neutralize as much as possible, such a problem can be solved and the amount of alkali required for neutralization can be reduced. The alkali concentration used for neutralization is arbitrary and may be any economical concentration. Usually, a sodium carbonate solution within 5% by weight is preferably used.

The organochlorosilane hydrolyzate concentration in the neutralization reactor is arbitrary, and the productivity can be selected by the ease of operation. Further, the neutralization temperature is not limited, but a higher temperature is preferable because the neutralization is performed more completely.

The method for hydrolyzing the organochlorosilane of the present invention may, of course, be a batch method (batch operation method) or a continuous production method, but the industrial continuous production method is preferred.

An example of the case where an organochlorosilane hydrolysis product is continuously obtained by the organochlorosilane hydrolysis method of the present invention will be described below with reference to FIG.

In the figure, 10 is a first-stage hydrolysis reactor, the raw material organochlorosilane is supplied from a pipe 11 and the methanol is supplied from a pipe 12 to the first-stage hydrolysis reactor 10,
Here, it is hydrolyzed by being stirred with a saturated hydrogen chloride solution to generate hydrogen chloride gas, and at the same time, a cyclic polyorganosiloxane, a linear polyorganosiloxane having a silanol group at the terminal, and a chlorine atom at the terminal reacting with an alcohol. The resulting product is an organochlorosilane hydrolysis product such as a linear polyorganosiloxane having an alkoxy group at the end. The residence time is 5 to 40 minutes. The obtained organochlorosilane hydrolysis product is discharged from the pipe 13 together with the saturated hydrogen chloride solution, phase-separated from the saturated hydrogen chloride solution in the first phase separator 20, and discharged from the pipe 21. At this time, the whole or part of the separated saturated hydrogen chloride solution is partially removed from the pipe 2.
It is economical to return the water from No. 2 to the first-stage hydrolysis reactor 10 and reuse it. In addition, this saturated hydrogen chloride aqueous solution is not directly circulated to the reactor 10 but is supplied to the mist separator 9
You may flush from the top of 0.

The organochlorosilane hydrolysis product discharged from the pipe 21 is supplied into the second-stage hydrolysis reactor 30, and is further hydrolyzed by being stirred with the dilute hydrogen chloride solution supplied from the pipe 31. The retention distillation time is preferably 5 to 30 minutes, and an alcohol may be contained in the dilute hydrogen chloride aqueous solution if necessary. Next, the organochlorosilane hydrolysis product is discharged from the pipe 32 together with the dilute hydrogen chloride solution and is phase-separated from the dilute hydrogen chloride solution in the second phase separator 40, and then the pipe 4
Emitted from 1. On the other hand, the separated dilute hydrogen chloride solution is returned from the pipe 42 to the first-stage hydrolysis reactor 10 and reused, whereby the hydrogen chloride can be completely recovered.

The phase-separated organochlorosilane hydrolysis product is then fed via tube 41 to the first neutralization reactor 50. Here, after being neutralized with the alkaline aqueous solution, it is discharged together with the alkaline aqueous solution, and is discharged from the pipe 51 to the third phase separator 6
0, and after being phase-separated from the alkali, it is supplied from the pipe 61 to the second neutralization reactor 70. On the other hand, the dilute alkaline aqueous solution is supplied from the pipe 71 to the second neutralization reactor 70. The organochlorosilane hydrolysis product neutralized in the second neutralization reactor 70 is introduced from the pipe 72 to the fourth phase separator 80, where it is separated from the dilute alkaline aqueous solution and discharged from the pipe 81, and then the tank. Etc. On the other hand, the separated diluted alkaline aqueous solution can be returned to the first neutralization reactor 50 through the pipe 82 and reused.

The hydrogen chloride gas generated from the first-stage hydrolysis reactor 10 is passed through the pipe 14 to the mist separator 90.
And is recovered from the pipe 91. The low molecular weight polyorganosiloxane or unreacted silane that accompanies the hydrogen chloride gas is captured by the mist separator 90 and returned to the reactor through the pipe 92.

In the above step, the neutralization reaction is carried out twice. However, if the first neutralization reaction is carried out sufficiently (if the residence time is long), the desired polyorganosiloxane can be obtained. It does not necessarily have to be done twice.

According to the above process, the hydrolysis product of organochlorosilane can be efficiently obtained without any inconvenience such as thickening continuously, and 100% of hydrogen chloride can be recovered.
The cost required for neutralization is also low, which is economically advantageous.

[0037]

EXAMPLES Hereinafter, the present invention will be specifically shown by showing Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Example 1] In the reaction step shown in FIG. 1, the hydrolysis reactors 10 and 30 are cylindrical reactors having a stirrer and having a heatable inner diameter of 13 cm and a height of 33 cm. To the hydrolysis reactor 10 [(CH ₃ ) ₂ Si
900 g of O] ₄ and 1300 g of water were charged, and HCl gas was blown at a reaction temperature of 35 ° C. while stirring with a stirrer to obtain a saturated aqueous chloride solution. Then, 51.5 g / min of dimethyldichlorosilane and 1% of 17% hydrogen chloride aqueous solution
8.0 g / min, methanol 7.08 g / min,
70.58 g / m of saturated hydrogen chloride aqueous solution (room temperature 25 ° C.)
was continuously supplied to the first-stage hydrolysis reactor 10. At this time, the total amount of the reactants in the first-stage hydrolysis reactor 10 is always equal to the total amount of [(CH ₃ ) ₂ SiO] ₄ charged before the reaction and the total amount of water, and the reactants are first fed from the tube 13 Phase separator 2
It was made to flow to 0. The first stage hydrolysis reaction conditions were set to a reaction temperature of 35 ° C. and an average residence time of 20 minutes, and the first phase separator 2
At 0, the temperature was set to room temperature (25 ° C.) and the residence time was set to 20 minutes.

The first phase separator 20 automatically separates an organochlorosilane hydrolyzate phase and an aqueous phase, and the separated organochlorosilane hydrolyzate is preliminarily charged with 1300 g of [(CH ₃ ) ₂ SiO] ₄ ; 1300 g of 17 wt% hydrogen chloride aqueous solution was charged and continuously supplied to the second-stage hydrolysis reactor 30 under stirring together with 15.5 g / min of 17 wt% hydrogen chloride aqueous solution. here,
70.5 g / min of separated water (circulation saturated hydrogen chloride aqueous solution) continuously separated by the first phase separator 20 is
The saturated hydrogen chloride aqueous solution of 70.5 g / min, which had been supplied to the first-stage hydrolysis reactor, was stopped, and instead, it was continuously introduced into the first-stage hydrolysis reactor by a pipe 22. The conditions for the second stage hydrolysis reaction were set to a reaction temperature of 35 ° C. and a residence time of 20 minutes. Also, as in the case of the first-stage hydrolysis, the amount of the reactant in the second-stage hydrolysis reactor 30 is always equal to the total amount of [(CH ₃ ) ₂ SiO] ₄ and water charged before the reaction. Was discharged to the second phase separator 40. The separation condition of the second phase separator 40 is that the temperature is room temperature and the residence time is 10 minutes.

A certain amount of the organochlorosilane hydrolysis product separated by the second phase separator 40 is subsequently continuously introduced into the first neutralization reactor 50, where the first neutralization reactor 50. The organochlorosilane hydrolyzate supplied to the above was mixed with an equal amount of a 5 wt% sodium carbonate aqueous solution, and the organochlorosilane hydrolyzate was continuously neutralized under the conditions of a reaction temperature of 80 ° C. and a residence time of 1 hour.

The neutralized product from the first neutralization reactor 50 was introduced into the third phase separator 60 and further into the second neutralization reactor 70. Here, the organochlorosilane hydrolyzate was separated by neutralizing in the same manner as in the first stage neutralization to obtain a colorless and transparent organochlorosilane hydrolyzate.

In the above-mentioned organochlorosilane hydrolysis step, the physical properties and reaction rate of the organochlorosilane hydrolysis product produced in each step when all the reaction steps reached a steady state under the set conditions were examined. The organopolychlorosilane hydrolyzate flowing out from the first phase separator 20 has a viscosity of 4.0 cs and a reaction rate of 98.4.
%, The organochlorosilane hydrolyzate flowing out from the second phase separator 40 has a viscosity of 5.8 cs, a reaction rate of 99.9%,
The organochlorosilane hydrolyzate separated after the second neutralization step of the target substance has a viscosity of 7.2 cs and [(CH ₃ ) ₂ Si
O] _3-6 content 72.2% by weight, of which [(CH ₃ )
₂ SiO] ₄ was 45.5% by weight.

[Examples 2 to 10] Organochlorosilane hydrolyzate was obtained in the same manner as in Example 1 except that the supply ratios of dimethyldichlorosilane, a circulating saturated hydrogen chloride solution and a dilute hydrogen chloride solution were changed. The experimental conditions at this time and the physical properties of the obtained polysiloxane product are shown in Table 1. In addition, Table 1 shows Example 1
The results of are also shown.

[0044]

[Table 1]

[Example 11] In Example 1, instead of dimethyldichlorosilane, a 1: 1 mixture of dimethyldichlorosilane and trichlorophenylsilane (weight ratio).
An experiment was conducted under the same conditions as in Example 1 except that a toluene solution containing 20% by weight of siloxane was introduced at 25 g / min. The viscosity of the obtained polyorganosiloxane (toluene solution) was 6 cs.

Comparative Example The same conditions as in Example 1 except that methanol was not supplied in the first-step reaction and the concentration of the dilute hydrogen chloride solution was 5% by weight in the second-step reaction. I did an experiment.

As a result, the reaction rate of the hydrolysis product obtained in the first-stage hydrolysis reaction was 97.4% and the viscosity of the hydrolysis product was 4.5 cs, which was obtained in the second-stage hydrolysis reaction. The reaction rate of the obtained hydrolysis product was 99.7%, and the viscosity of the hydrolysis product was 9.1 cs. When this is then introduced into the neutralization step, the viscosity increases sharply and the third phase separator 60
It was also found that the separation of the siloxane layer in the fourth phase separator 80 is extremely difficult, and the phase separation does not occur cleanly even if the residence time is several hours, which is extremely industrially problematic.

From the above results, by carrying out the hydrolysis reaction in two stages and hydrolyzing the organochlorosilane in the first stage in the presence of alcohol, the hydrolyzate of polyorganochlorosilane and the aqueous solution of hydrogen chloride were obtained. It is recognized that the separation of is very good, the reaction rate is improved (improvement of hydrogen chloride recovery efficiency), the neutralization step is facilitated, and an economical continuous hydrolysis reaction is possible.

The polyorganosiloxane product obtained by the hydrolysis method of the above example was used as a starting material to synthesize a silicone oil by an alkali catalyst method or a sulfuric acid catalyst method, and the influence of a small amount of terminal alkoxypolysiloxane was investigated. As a result, the polymerization reaction proceeded without gelation, and the effect was not recognized.

[0050]

As described above, according to the organochlorosilane hydrolysis method of the present invention, a polyorganosiloxane can be obtained industrially advantageously.

[Brief description of drawings]

FIG. 1 is a process drawing showing an example of the present invention.

[Explanation of symbols]

 10 1st stage hydrolysis reactor 20 1st phase separator 30 2nd stage hydrolysis reactor 40 2nd phase separator 50 1st neutralization reactor 60 3rd phase separator 70 2nd neutralization reactor 80 4-phase separator 90 mist separator

Claims (7)

[Claims] 1. A method for producing a polyorganosiloxane by hydrolyzing an organochlorosilane, wherein the first-step hydrolysis is carried out in a saturated hydrogen chloride solution in the presence of alcohol, and the second-step hydrolysis is carried out in a dilute hydrogen chloride solution. And a method for hydrolyzing organochlorosilane, which is characterized in that 2. The method for hydrolyzing organochlorosilane according to claim 1, wherein the hydrolysis reaction temperature of the organochlorosilane in the first stage hydrolysis is 30 to 60 ° C. 3. The method for hydrolyzing organochlorosilane according to claim 1, wherein the alcohol used in the first-step hydrolysis is methanol. 4. The method for hydrolyzing an organochlorosilane according to claim 1, 2 or 3, wherein the amount of the alcohol used in the first-step hydrolysis is 10 to 35% by weight based on the organochlorosilane. 5. The method for hydrolyzing an organochlorosilane according to claim 1, wherein the organochlorosilane hydrolysis product in the first stage hydrolysis is 20 to 40% by weight based on the total reaction system. .. 6. The second stage hydrolysis reaction is carried out at a reaction temperature of 40 ° C.
The method for hydrolyzing organochlorosilane according to claim 1, wherein the hydrogen chloride concentration of the dilute hydrogen chloride aqueous solution is 20% by weight or less. 7. The method for hydrolyzing an organochlorosilane according to claim 1, wherein the first stage hydrolysis and the second stage hydrolysis are continuously performed.