JP3159638B2 - Method for producing 3-mercaptopropylalkoxysilane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing 3-mercaptopropylalkoxysilane useful as a silane coupling agent.

[0002]

2. Description of the Related Art Conventionally, as a method for producing mercaptoalkylalkoxysilane, a reaction of haloalkylalkoxysilane with thiourea in the presence of ammonia is known (Japanese Patent Publication No. 50-7587). However, this reaction has a problem that guanidine hydrochloride having a bulky property as a by-product and difficult to dispose is generated.

As another method, a method of reacting a haloalkylalkoxysilane with hydrogen sulfide in the presence of an amine is known (Japanese Patent Publication No. 60-2312), but this reaction is carried out under a high pressure of 16 kg / cm ^2. There is a problem that must be done.

[0004] An addition reaction of hydrogen sulfide to alkenylalkoxysilane is known (US Pat. No. 3,902,902).
13) Since the generated mercaptoalkylalkoxysilane is further added to the raw material alkenylalkoxysilane, there is a problem that a large amount of a sulfide compound is by-produced.

Further, a method of reacting sodium methoxide with hydrogen sulfide and then reacting with haloalkylalkoxysilane, for example, a method in which the reaction is carried out at room temperature in a methanol solution of sodium hydrosulfide (UK Patent No. 1102225)
No. 1) and a method in which sodium hydrosulfide is dissolved in a polar aprotic solvent represented by dimethylformamide and reacted at normal pressure (JP-A-4-261188) is known. In the reaction with hydrogen, sodium sulfide is produced as a by-product, and if it is not removed, a large amount of sulfide compound is produced as a by-product, and it is also difficult to remove this.

[0006] Further, British Patent No. 1122251 has disadvantages that cannot be ignored in practical use, such as requiring an extraordinarily long time of 4 days for the reaction and a low conversion rate. In Japanese Patent Application Laid-Open No. 4-261188, since a solvent having a high boiling point is used, a distillation column having a relatively high theoretical plate number is required for distillation separation with a product, and the energy required for the separation causes an increase in the production cost of mercaptosilane. Also,
Due to the high solubility of the solvent, salts that could not be separated before distillation are transferred to the distillation still liquid, which has the drawback of reducing the distillation recovery of the product.

Further, a drawback common to these methods is that the yield is only about 80%. Therefore, not only is economic efficiency degraded due to low yield,
Since the raw materials and by-products remaining after the reaction contain harmful substances, performing these treatments requires considerable costs,
It is not satisfactory for mass production on an industrial scale.

[0008]

In order to eliminate the drawbacks of these known processes and to produce industrially inexpensive and large-scale production, it is necessary to use inexpensive raw materials and achieve high conversion rates in a short time. There is. That is, the conversion rate from 3-chloropropylalkoxysilane, which is a raw material, to 3-mercaptopropylalkoxysilane, which is a target substance, is significantly increased,
It is necessary to suppress the generation of components other than the by-products as the by-products, to reduce the load on post-processing, and to produce the product in a short time using a simple production apparatus.

An object of the present invention is to provide a novel process for producing 3-mercaptopropylalkoxysilane in a high yield under mild conditions and at the same time suppressing by-products of sulfide compounds, and at the same time, easily producing a salt that can be easily disposed of. It is to provide a method.

[0010]

The present invention relates to an alkali metal hydride and a general formula X (CH ₂ ) ₃ Si (OR) _a R _3-a (I) wherein X represents Cl or Br. Represents a methyl group, an ethyl group, or a propyl group, and may be the same or different; a represents an integer of 1, 2, or 3); A method for producing 3-mercaptopropylalkoxysilane, comprising reacting under pressure and in the presence of excess hydrogen sulfide.

Hereinafter, the present invention will be described in detail. The 3-halopropylalkoxysilane used in the present invention has a general formula X (CH ₂ ) ₃ Si (OR) _a R _3-a (I) (X represents Cl or Br. R represents a methyl group or an ethyl group. And a propyl group, which may be the same or different, and a represents an integer of 1, 2, or 3.) Specifically, Cl (CH ₂ ) ₃ Si (OMe) _{3 Br (CH 2) 3 Si} (OMe) 3 Cl (CH 2) 3 Si (OMe) 2 Me Cl (CH 2) 3 Si (OEt) 3 Cl (CH 2) 3 Si (OPr) 2 Me Cl (CH _{2) 3 Si (OMe) Me} 2 and the like.

As the silane coupling agent, dialkoxysilane or trialkoxysilane in which a is 2 or 3 is preferable, and trialkoxysilane is particularly preferable. R
Is preferably a methyl group or an ethyl group, particularly preferably a methyl group, from the viewpoint of reactivity and availability of raw materials.

Among the above-mentioned 3-halopropylalkoxysilanes, Cl (CH ₂ ) ₃ Si (OMe) ₃ or Br (CH ₂ ) ₃ Si (OMe) ₃ is most preferred, and HS (CH ₂ ) ₃ obtained therefrom. Si
(OMe) ₃ is useful.

[Reaction of alkali metal hydride with 3-halopropylalkoxysilane]

This reaction is carried out in the following manner: NaOMe + H ₂ S → NaSH + MeOH NaSH + X (CH ₂ ) ₃ Si (OR) _a R _3-a → HS (CH ₂ ) ₃ Si (OR) _a R _3-a + It is represented by NaX.

[0016] Incidentally, side _{reactions, 2NaOMe + H 2 S → Na} 2 S + 2MeOH Na 2 S + 2X (CH 2) 3 Si (OR) a R 3-a → S {(CH 2) 3 Si (OR ) _a R _3-a} is represented by ₂ + 2NaX, is sodium sulfide resulting from the side reaction shown in cause, reaction sulfide is by-produced by the.
In the presence of hydrogen sulfide in the present invention and under a closed condition, when sodium bisulfide is consumed by the reaction, the next equilibrium reaction proceeds to the right, and sodium sulfide by-produced decreases. By-products of sulfide can be suppressed. 1 / 2Na ₂ S + 1 / 2H ₂ S → NaSH

On the other hand, in the method of blowing hydrogen sulfide during the reaction in an open system, the dissolved amount of hydrogen sulfide is insufficient,
Since the equilibrium reaction of does not proceed to the right and sodium sulfide remains, it is considered that the amount of sulfide by-product increases.

The details of the above reaction will be described. This reaction is
Usually, the reaction is performed using an alcohol solvent such as methanol or ethanol.

Examples of the alkali metal sulfide used in the present reaction include sodium bisulfide and potassium bisulfide, with sodium bisulfide being particularly preferred. Although sodium hydrosulfide produced outside the system may be used, sodium hydrogen sulfide is usually synthesized by injecting hydrogen sulfide into a sodium alcoholate alcohol solution in the system.

In the present invention, hydrogen sulfide is further forcibly injected into this solution, so that excess hydrogen sulfide is present in the system.
This injection is preferably performed gradually because hydrogen sulfide needs time to dissolve in the alcohol solution of sodium bisulfide. Further, the pressure in the system gradually increases, and thereafter, a pressurizing operation is performed.

Specifically, when the concentration of the methanol solution of sodium methylate is 24 to 28%, 1.1 to 2.0 mol, preferably 1. mol to 1 mol of sodium methylate.
1 to 1.5 mol, particularly preferably 1.3 to 1.5 mol, of hydrogen sulfide are initially injected at normal pressure and subsequently forcedly injected under pressure. The temperature at this time is preferably 50 ° C. or less, and if it is 30 ° C. or less, the injection can be performed at a relatively easy-to-handle pressure of ² kg / cm ² or less. Therefore, injection of hydrogen sulfide needs to be performed in a pressure-resistant device. The injection time is usually about one hour after sodium hydrogen sulfide is generated and the injection of excess hydrogen sulfide is started, but it can be shortened by increasing the injection pressure. However, when the injection of hydrogen sulfide is performed in two stages due to the handling of the manufacturing apparatus, the first-stage injection is adjusted so that hydrogen sulfide is 1.1 mol or less per mol of sodium methylate. Thus, the first stage production apparatus of sodium hydrosulfide does not require pressure resistance.

Sodium hydrosulfide is used in an amount of from 1.03 to 1: 1 based on 1 mol of the reacted 3-halopropylalkoxysilane.
20 moles, preferably 1.03 to 1.05 moles are used. Hydrogen sulfide is present in the reaction system in an amount of 0.1 to 1.0 mol, preferably 0.1 to 0.5 mol, per 1 mol of the sodium hydrosulfide. Hydrogen sulfide may be charged in its entirety before adding 3-halopropylalkoxysilane, or may be charged separately before or during the reaction.

The alcohol solution of sodium hydrogen sulfide in which hydrogen sulfide is dissolved is heated to a reaction temperature of 50 to 100 ° C., preferably 65 to 100 ° C. in a closed state. At this time, the pressure is 2.0 to 5.0 kg / cm ² . Here, 3-halopropylalkoxysilane is gradually dropped. Dropping 3-halopropylalkoxysilane into sodium bisulfide works advantageously for suppressing the formation of sulfides as by-products.

When the dropping time is at least 1 hour, preferably 1 to 3 hours, the formation of by-product sulfide can be similarly suppressed. However, over 3 hours, there is not much improvement as compared to dropping in 3 hours.

When 3-halopropylalkoxysilane is dropped into sodium bisulfide, the pressure in the system gradually decreases, and hydrogen sulfide is injected under pressure to increase the pressure to 0.5-4.
0 kg / cm ² , preferably 2.0 to 4.0 kg / cm ²
A more favorable result is obtained when the temperature is kept at. From the beginning of the reaction, it is possible to slightly increase the pressure of hydrogen sulfide so that the pressure falls within the above range even after the pressure drop due to the reaction.

The aging of the liquid after dropping is completed in a shorter time as the temperature is higher. The aging temperature may be 70 ° C. or higher, but is preferably 90 ° C. or higher and 120 ° C. or lower. 7
In the case of 0 ° C or lower, aging requires 5 hours or more,
If the temperature is higher than 20 ° C., a large load is applied to the pressure resistance of the device.

A feature of the present invention resides in that hydrogen sulfide which is considered unnecessary for the original reaction is present in the system before and during the addition of the 3-halopropylalkoxysilane.
This operation has the effect of suppressing the formation of sulfide bodies to about 1%, which was conventionally unavoidable in about 5 to 10%. In addition, since the reaction is carried out in a closed state, hydrolysis is not caused by water entering from the atmosphere to produce a polymer, and a high yield is obtained.

[0028]

Hereinafter, the present invention will be described in detail with reference to Examples.
The present invention is not limited by these examples.

COMPARATIVE EXAMPLE 1 In a 1-liter four-necked flask equipped with a stirrer, a reflux condenser, a thermometer, a gas injection tube, and a dropping funnel, 462.9 g (2.4 m) of a 28% methanol solution of sodium methoxide was placed.
ol) and 92.2 g of hydrogen sulfide from a gas injection tube
(2.71 mol) was blown in at a temperature of 30 to 40 ° C. over 3 hours. After heating until the internal temperature reaches 70 ° C,
397.4 g (2.0 mol) of 3-chloropropyltrimethoxysilane was dropped from the dropping funnel over 1 hour,
The reaction was performed at 65 to 75 ° C. After the completion of dropping, the temperature should be 60 ~
Aged at 70 ° C. for 3 hours. The reaction solution was cooled and then filtered to remove sodium chloride. Here, when the filtrate was analyzed by gas chromatography,
The product ratio was as shown below, and a large amount of sulfide was formed. _{HS (CH 2) 3 Si (} OMe) 3 50.1% S {(CH 2) 3 Si (OMe) 3} 2 49.9%

Comparative Example 2 Into a 1-liter four-necked flask equipped with a stirrer, a reflux condenser, a thermometer, a gas injection tube, and a dropping funnel, 462.9 g (2.4 m) of a 28% methanol solution of sodium methoxide was placed.
ol) and 95.8 g of hydrogen sulfide from a gas injection tube
(2.81 mol) was blown at a temperature of 30 to 40 ° C. over 3 hours. After heating until the internal temperature reaches 70 ° C,
397.4 g (2.0 mol) of 3-chloropropyltrimethoxysilane was dropped from the dropping funnel, and simultaneously, 48.4 g (1.42 mol) of hydrogen sulfide was blown from a gas blowing tube to react at 65 to 75 ° C. over 1 hour. I let it. After dropping and blowing, keep the temperature at
Aged for hours. The reaction solution was cooled and then filtered to remove sodium chloride. Here, when the filtrate was analyzed by gas chromatography, the product ratio was as shown below, and a large amount of sulfide was formed. HS (CH ₂ ) ₃ Si (OMe) ₃ 81.7% S {(CH ₂ ) ₃ Si (OMe) ₃ } ₂ 18.3%

Example 1 In a 1-liter autoclave, 267.6 g (1.05%) of a 22% methanol solution of anhydrous sodium hydrosulfide was added.
mol), and the space was replaced with nitrogen. Next, 0.3 mol of hydrogen sulfide was blown into the system to 0.9 kgf / c.
The pressure was increased to m ² to supersaturate the hydrogen sulfide. After heating to 70 ° C, 3-chloropropyltrimethoxysilane 19
8.7 g (1.0 mol) was added dropwise over 3 hours, and during the addition, 0.05 mol of hydrogen sulfide was blown into the system to weigh 2.5 kg.
f / cm ² . After completion of the dropwise addition, the temperature was raised to 100 ° C., aged for 1 hour, and then cooled. The salts produced as a by-product of the reaction were separated by filtration and the components were analyzed by gas chromatography. As a result, 3-mercaptopropyltrimethoxysilane was obtained in a yield of 94.1%.

Example 2 In a 1-liter autoclave, 267.6 g (1.05%) of a 22% methanol solution of anhydrous sodium hydrosulfide was added.
mol), and the space was replaced with nitrogen. Next, 0.3 mol of hydrogen sulfide was blown into the system to 0.9 kgf / c.
The pressure was increased to m ² to supersaturate the hydrogen sulfide. After heating to 90 ° C, 3-chloropropyltrimethoxysilane 19
8.7 g (1.0 mol) was added dropwise over 3 hours, and 0.1 mol of hydrogen sulfide was blown into the system to add 3.5 kgf.
/ Cm ² . After completion of the dropwise addition, the mixture was aged at 90 ° C. for 2 hours and then cooled. Salts by-produced in the reaction were separated by filtration and the components were analyzed by gas chromatography.
Mercaptopropyltrimethoxysilane was obtained in a yield of 93.5%.

Comparative Example 3 In a 1-liter autoclave, 267.6 g (1.05%) of a 22% methanol solution of anhydrous sodium hydrosulfide was added.
mol), and the space was replaced with nitrogen. After heating to 70 ° C, 3-chloropropyltrimethoxysilane 19
8.7 g (1.0 mol) were injected. After aging for 4 hours at 70 ° C., the mixture was cooled after 3-chloropropyltrimethoxysilane had disappeared. The pressure in the system during ripening is 0.7-0.
It was 9 kgf / cm ² . Salts produced as a by-product of the reaction were separated by filtration and the components were analyzed by gas chromatography. As a result, it was found that 3-mercaptopropyltrimethoxysilane was 8%.
Obtained in 1.0% yield.

Comparative Example 4 308 g of a 20% solution of anhydrous sodium hydrosulfide in dimethylformamide (1.
1 mol), and the space was replaced with nitrogen. 110 ° C
After that, 198.7 g (1.0 mol) of 3-chloropropyltrimethoxysilane was injected. After aging at 110 ° C for 2 hours, 3-chloropropyltrimethoxysilane disappeared and then cooled. Salts produced as a by-product of the reaction were separated by filtration and the components were analyzed by gas chromatography. As a result, it was found that 3-mercaptopropyltrimethoxysilane was 8%.
Obtained in a yield of 3.6%.

Comparative Example 5 267.6 g (1.05 m) of a 22% methanol solution of anhydrous sodium hydrosulfide was placed in a four-necked flask having a content of 1 liter.
ol) and the space was replaced with nitrogen. 198.7 g of 3-chloropropyltrimethoxysilane (1.0 mo
l) was injected and aged at room temperature for 4 days to eliminate 3-chloropropyltrimethoxysilane. Salts produced as a by-product of the reaction were separated by filtration and the components were analyzed by gas chromatography. As a result, 3-mercaptopropyltrimethoxysilane was obtained in a yield of 40.3%.

[0036]

The present invention is superior to the known method in the following points. (1) In the present invention, the yield of the reaction is superior to that of the known method. In addition, the generation of by-products containing harmful components is greatly suppressed, and the burden on waste disposal and the like is reduced. (2) Since the reaction apparatus is simple and methanol, which is easily recovered, is used as a solvent, the load on post-treatment for purification is reduced. (3) The time required from the start of injecting hydrogen sulfide into sodium hydrosulfide to the end of the reaction is short, and it is practical as an industrial production method.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shoji Ichinohe 1-10 Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture Inside Silicone Electronics Materials Research Laboratory Shin-Etsu Chemical Co., Ltd. (72) Inventor Akira Yamamoto Matsui, Usui-gun, Gunma Prefecture Hitomi Tamachi 1-10 Shin-Etsu Chemical Co., Ltd.Silicone Electronic Materials Research Laboratory (72) Akira Beppu 2-2-32 Kasugano, Joetsu-shi, Niigata Prefecture (72) Inventor Hiroyuki Iwaki Fujisawa Nakago-mura, Nakakubijo-gun, Niigata Prefecture 1072-1-401 (72) Inventor Satoshi Sekizawa 267-1-303, Honmachi, Takaoka-shi, Toyama (56) References JP-A-4-261188 (JP, A) JP-A-4-120052 (JP, A) JP-A-63-10755 (JP, A) British Patent 1102251 (GB, B) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07F 7/18 CA (STN) CAOLD (STN) REGISTRY (STN)

Claims (3)

(57) [Claims] 1. An alkali metal hydride and a general formula X (CH ₂ ) ₃ Si (OR) _a R _3-a (I) (X represents Cl or Br. R represents a methyl group, an ethyl group, or a propyl group. And a may represent the same or different. A represents an integer of 1, 2, or 3.) and a 3-halopropylalkoxysilane represented by A method for producing 3-mercaptopropylalkoxysilane, characterized by satisfying the following conditions (1), (2) and (3). (1) 0.1 mole per mole of alkali metal hydride.
Use 1-1.0 moles of hydrogen sulfide. (2) The pressure in the system is 0.5 to 4.0 kg / cm at room temperature.
^{Being 2} (3) After heating an alcohol solution of an alkali metal hydride pressurized with hydrogen sulfide to 50 to 100 ° C.,
Dropping halopropylalkoxysilane. 2. The method according to claim 1, wherein the 3-halopropylalkoxysilane is
2. The method according to claim 1, wherein the method is 3-halopropyltrimethoxysilane. 3. The method according to claim 1, wherein the alkali metal hydride is obtained by reacting sodium methoxide with hydrogen sulfide.