JPH05310756A - Production of cyclohexylmethyldialkoxysilane - Google Patents

Abstract

PURPOSE:To obtain a completely alkoxylated cyclohexylmethyldialkoxysilane in a short time by rapidly removing hydrogen chloride formed from a cyclohexylmethyldichlorosilane and a monohydric saturated alcohol as a by- product to the outside of the reactional system according to liquid separating operation. CONSTITUTION:The method for producing a cyclohexylmethyldialkoxysiane is to mix a cyclohexylmethyldichlorosilane with a monohydric saturated alcohol in a theoretically equimolar amount or more divided in an molar amount of >=1 to <=2 times in the first-stage reaction and then >=3 to <=5 times in the second-stage reaction based on chlorine atoms at <=40 deg.C liquid temperature, react both and simultaneously remove the hydrogen chloride-containing alcohol in the upper layer to the outside of the system by allowing the reaction solution to stand or liquid separating operation using the saturated alcohol as an absorbent for the hydrogen chloride formed as a by-product. In the method, the cyclohexylmethyldialkoxysilane containing >=0.5wt.% hydrogen chloride due to the reaction is finally separated and the remaining hydrogen chloride in the separated and collected alkoxysilane is neutralized with a sodium alkoxide in an equimolar amount of more.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing cyclohexylmethyldialkoxysilane, and more specifically, mixing cyclohexylmethyldichlorosilane and monovalent saturated alcohol to obtain an alkoxysilane by liquid separation operation and neutralization with a neutralizing agent. And a method for producing cyclohexylmethyldialkoxysilane. The cyclohexylmethyldialkoxysilane obtained in the present invention is a compound useful as a substance added to a polymerization catalyst of polyolefin, particularly polypropylene.

[0002]

TECHNICAL BACKGROUND AND PROBLEMS OF THE INVENTION The following methods are known as methods for alkoxylating chlorosilane compounds. Method using orthoformate [J. Amer. Chem. So
c., Vol. 76, p. 1390 (1954) Method of reacting monovalent saturated alcohol and adding base such as amine as scavenger of by-produced hydrogen chloride. Method of blowing active gas into the reaction system to remove by-product hydrogen chloride to the outside of the reaction system Method of reacting monovalent saturated alcohol and then refluxing with a low boiling point solvent to remove by-product hydrogen chloride to the outside of the reaction system A method of reducing the by-product hydrogen chloride by reducing the pressure of the reaction system after reacting a monovalent saturated alcohol. However, in the case of alkoxylating cyclohexylmethyldichlorosilane, the alkoxylation hardly progresses by the method. Further, in the method (1), the operation is complicated because the hydrochloride produced as a by-product is separated and the salt is difficult to handle. In addition, since the methods of and are equilibrium reactions, the removal of by-product hydrogen chloride to the outside of the system is rate-determining and it takes time to manufacture, and the removal of chlorine atoms bonded to silicon atoms (hereinafter referred to as "chlorosilane content"). However, there is a problem in that the yield is lowered because condensation of side reaction occurs due to the chlorosilane content. On the other hand, diphenyldichlorosilane was alkoxylated with a monovalent saturated alcohol, this alcohol was used as a by-product hydrogen chloride absorbing (scavenging) agent, and the fact that the product was insoluble in the alcohol containing hydrogen chloride was used. There is known a method for producing diphenyl dialkoxy silane in which hydrogen chloride is removed by a liquid separation operation (Japanese Patent Laid-Open No. 61-72791). However, when this method is applied to the production of cyclohexylmethyldialkoxysilane, when the content of chlorine in the alcohol is 0.5 wt% or less in terms of hydrogen chloride conversion,
Since the alcohol and the product cyclohexylmethyldialkoxysilane are uniformly dissolved, there is a drawback that further improvement in purity and / or yield cannot be obtained.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a method capable of producing cyclohexylmethyldialkoxysilane with high purity and yield in a short time.
In order to achieve the above object, the present inventors have proposed a method for removing hydrogen chloride generated when a cyclohexylmethyldichlorosilane is reacted with a monovalent saturated alcohol, and a chlorine content that remains in a trace amount after removal of by-product hydrogen chloride. As a result of various studies on the effective removal method of the chlorosilane component and / or hydrogen chloride in the reaction system, the hydrolysis of cyclohexylmethyldichlorosilane (condensation of side reaction) was slow in the reaction system at 40 ° C or lower, and the monovalent saturated alcohol was It is a hydrogen chloride absorbent that is as good as water, and if the content of chlorine in cyclohexylmethyldichlorosilane in hydrogen chloride-containing monovalent saturated alcohol is 0.5% by weight or more in terms of hydrogen chloride, Of the cyclohexylmethyldichlorosilane by using a neutralizing agent. The Roroshiran min Noting that can be completely neutralized, and completed the present invention.

[0004]

That is, according to the present invention, cyclohexylmethyldichlorosilane is added with a theoretically equimolar or more monovalent saturated alcohol relative to the chlorine atom thereof at a liquid temperature of 40 ° C. or lower,
In the first-step reaction, 1-fold moles to 2-fold moles, in the second-step reaction, 3-fold moles to 5-fold moles, the mixture is divided and reacted, and the saturated alcohol is used as a by-product hydrogen chloride absorbent. In the method for producing cyclohexylmethyldialkoxysilane in which the upper layer hydrogen chloride-containing alcohol is removed from the system by standing and separating, cyclohexylmethyldialkoxy whose content of chlorine obtained by the above reaction is 0.5% by weight or more in terms of hydrogen chloride equivalent concentration. It is characterized in that silane (or alkoxylated cyclohexylmethyldichlorosilane) is finally separated, and the residual chlorine in the separated alkoxysilane is neutralized with sodium alkoxide equivalent to or more than hydrogen chloride equivalent. This is a method for producing cyclohexylmethyldialkoxysilane. The method of the present invention is a stepwise reaction of cyclohexylmethyldichlorosilane and a monovalent saturated alcohol, while partially substituting a chlorine group with an alkoxy group, while absorbing by-produced hydrogen chloride into the unreacted alcohol. This is a method of finally obtaining cyclohexylmethyldialkoxysilane completely alkoxylated with a neutralizing agent while taking it out of the system by a liquid separation operation. The monovalent saturated alcohol used in the present invention, from the point of insolubility of the alcohol and cyclohexylmethylsilane compound, which will contain hydrogen chloride,
Methanol is preferred. However, if it is replaced with a completely alkoxylated cyclohexylmethyldialkoxysilane, it will not separate from the monovalent saturated alcohol, so 0.5% by weight or more of chlorosilane in cyclohexylmethyldialkoxysilane is required in terms of hydrogen chloride. , This 0.
Neutralizing agents, especially sodium alkoxides, are suitable for neutralizing cyclohexylmethyldialkoxysilanes containing 5% by weight or more of chlorosilane.

The manufacturing method of the present invention will be described in detail below. This reaction can be roughly divided into four stages. That is, cyclohexylmethyldichlorosilane is mixed with a monohydric saturated alcohol of 1 mol to 2 mol in a liquid temperature of 40 ° C. or lower, and the mixture is stirred for about 5 to 30 minutes, then allowed to stand and separated,
First-step reaction to obtain a partially alkoxylated silane compound by removing the hydrogen chloride-containing alcohol in the upper layer outside the system The partially alkoxylated silane compound in this reaction is approximately 15% in terms of hydrogen chloride. Contains chlorosilane. On the other hand, the alcohol containing hydrogen chloride in the upper layer is
It contains about 30% hydrogen chloride. Next, add 40 ° C to this partially alkoxylated silane compound.
Mix monohydric saturated alcohol under the above liquid temperature,
After stirring for 30 minutes, the solution is allowed to stand and separate to remove the upper layer hydrogen chloride-containing alcohol from the system to obtain an almost alkoxylated silane compound. Second-stage reaction Monovalent saturated alcohol used here The amount of hydrogen chloride is determined by the concentration of hydrogen chloride dissolved in this monohydric saturated alcohol. When the amount is small, the amount of unreacted chlorosilane in the obtained alkoxylated silane compound is large, and when it is too large, Since the concentration of hydrogen chloride dissolved in a saturated alcohol having a valency is too low and the liquid separation property is deteriorated, it is preferable to use 3 times or more and 5 times or less mol of the reacted cyclohexylmethyldichlorosilane. Further, in order to improve the dissolution efficiency of hydrogen chloride in the monovalent saturated alcohol, the monovalent saturated alcohol to be used may be divided and used in an appropriate amount. In this case, the number of liquid separation operations increases. The silane compound almost alkoxylated by this reaction contains 4 to 5% of chlorosilane in terms of hydrogen chloride.
On the other hand, the hydrogen chloride-containing alcohol in the upper layer contains about 15% hydrogen chloride. The liquid separation operation may be repeated using an appropriate amount of monohydric saturated alcohol, but if the concentration of hydrogen chloride in the alkoxylated silane compound is less than 0.5% by weight, liquid separation with alcohol will not be possible. Therefore, it is necessary to stop at higher hydrogen chloride concentration. Next, the third step reaction in which about 10% of the remaining hydrogen chloride-containing alcohol contained in the almost alkoxylated silane compound obtained by liquid separation is distilled off. A normal pressure system or a reduced pressure system may be used, but a reduced pressure system is preferable in view of shortening the process time. Finally, the fourth step reaction in which a partially unreacted chlorosilane in the almost alkoxylated silane compound is neutralized with a neutralizing agent. The neutralizing agent used in this reaction is an organic amine such as pyridine or ethylenediamine. Since it is difficult to completely neutralize partially unreacted chlorosilane with a system compound,
Sodium alkoxide is used, and sodium methoxide is particularly preferable. The sodium alkoxide may be used by dissolving it in alcohol, but it is preferably used as it is from the viewpoint of the separability of the neutralized salt produced as a by-product.
The sodium alkoxide used may be an equimolar amount or more of the amount of chlorosilane calculated as hydrogen chloride by titration, but is preferably 1.1 to 2 times the molar amount. The cyclohexylmethyldialkoxysilane completely neutralized as described above is highly purified by a purification method such as distillation. The reactor is not critical and there is no problem if stirring, liquid separation operation and temperature control are possible.

[0006]

EXAMPLES Next, the present invention will be described more specifically by way of examples. All parts in the examples are parts by weight. Example 1 200 parts of methanol was added dropwise to 985 parts of cyclohexylmethyldichlorosilane at 25 ° C. over 10 minutes. After the dropwise addition was completed, stirring was continued for 5 minutes, then, the mixture was allowed to stand and liquid separation was performed to remove 978 parts of the lower layer silane composition liquid, and the upper layer was discarded. The silane composition solution was brought to 25 ° C again, and 520 parts of methanol was added to the reaction solution at a temperature of 40 ° C.
The dropping speed was adjusted so that the temperature became not higher than 0 ° C., the mixture was added over 1 hour, the mixture was stirred for 5 minutes, allowed to stand, and liquid-separated to collect 931 parts of crude cyclohexylmethyldimethoxysilane in the lower layer. 40% of this crude cyclohexylmethyldimethoxysilane
The mixture was heated to ℃ and the methanol was distilled off under reduced pressure to obtain 837 parts of cyclohexylmethyldimethoxysilane containing 3.7% of chlorosilane converted as hydrogen chloride. 72 parts of powdered sodium methoxide was added thereto over 30 minutes, and stirring was continued for 30 minutes to complete the neutralization. By filtration and distillation of neutralized salts
99.2% pure cyclohexylmethyldimethoxysilane
I got 690 copies. The yield was 73.4% (relative to cyclohexylmethyldichlorosilane).

Example 2 In the same manner as in Example 1, 928 parts of cyclohexylmethyldimethoxysilane containing 4.2% hydrogen chloride-containing methanol as hydrogen chloride was obtained before the operation of distilling off methanol under reduced pressure. To this was added 278 parts of methanol, and the mixture was stirred for 5 minutes, allowed to stand, and separated to obtain 882 parts of crude cyclohexylmethyldimethoxysilane. This crude cyclohexylmethyldimethoxysilane is heated to 40 ° C, methanol is distilled off under reduced pressure, and cyclohexylmethyldimethoxysilane containing 1.5% of chlorosilane converted as hydrogen chloride is used.
I got two copies. 28 parts of powdered sodium methoxide was added thereto over 5 minutes, and stirring was continued for 30 minutes to complete neutralization.
The neutralized salt was filtered and distilled to obtain 702 parts of 99.4% pure cyclohexylmethyldimethoxysilane. Yield 74.7
% (Vs. cyclohexylmethyldichlorosilane).

Comparative Example 1 A reaction kettle charged with 308 parts of cyclohexylmethyldichlorosilane was depressurized to 30 cmHg and heated to a liquid temperature of 60 ° C. While maintaining the degree of vacuum at 30 to 40 cmHg and the liquid temperature at 40 to 70 ° C, 480 parts of methanol was added dropwise thereto over 3 hours. The hydrolyzate was contained at 30% at the end of the dropping. When this reaction product was distilled under reduced pressure, 131 parts of cyclohexylmethyldimethoxysilane was obtained. The yield was 44.7% (based on cyclohexylmethyldichlorosilane).

[0009]

INDUSTRIAL APPLICABILITY According to the present invention, hydrogen chloride produced as a by-product in the reaction between cyclohexylmethyldichlorosilane and a monovalent saturated alcohol can be promptly removed to the outside of the system by a liquid separation operation, and a trace amount of residual chlorosilane can be obtained. The component can be almost completely neutralized, and a highly pure cyclohexylmethyldialkoxysilane that is completely alkoxylated can be produced in a good yield in a short time.

Claims (1)

[Claims] 1. A cyclohexylmethyldichlorosilane containing a theoretically equimolar or more monohydric saturated alcohol with respect to its chlorine atom at a liquid temperature of 40.degree. , 3 times mole or more in the second reaction 5
A process for producing cyclohexylmethyldialkoxysilane, which removes the upper layer hydrogen chloride-containing alcohol out of the system by standing and separating, using the saturated alcohol as a by-product hydrogen chloride absorbent while reacting by dividing and mixing in equal to or less than twice the molar amount. In the above, in the final separation of cyclohexylmethyldialkoxysilane (or alkoxylated cyclohexylmethyldichlorosilane) having a chlorine content of 0.5% by weight or more as a hydrogen chloride equivalent concentration obtained by the above reaction, and then the separated alkoxysilane A method for producing cyclohexylmethyldialkoxysilane, characterized in that residual chlorine in the solution is neutralized with sodium alkoxide equivalent to or greater than hydrogen chloride.