JP4193051B2 - Method for producing 3-mercaptopropylalkoxysilane - Google Patents

Description

  The present invention relates to a method for producing 3-mercaptopropylalkoxysilane containing a 3-mercaptopropyl group useful as a silane coupling agent, a modified silicone raw material, a plastic modifier, and the like.

  3-mercaptopropyltrialkoxysilane or 3-mercaptopropylmonoalkyldialkoxysilane is generally known as a silane coupling agent, and includes inorganic materials such as glass, metal, and silica and organic materials such as general-purpose synthetic resins. It is used in various fields as an adhesive that can be firmly bonded chemically. General-purpose synthetic resins that can be applied include thermoplastic resins such as polyethylene, polypropylene, polystyrene, and polyvinyl chloride, thermosetting resins such as epoxy resins and urethane resins, urethane rubber, polysulfide, styrene butadiene rubber (SBR), nitrile rubber, S A wide range of elastomers such as cross-linked ethylene propylene monomer (EPM) and rubber. In particular, when silica, clay, talc or the like chemically treated with the above alkoxysilane is added to a sulfur vulcanized elastomer (such as S-crosslinked EPM), it is known to greatly improve the physical properties of the elastomer. ing. In addition, it is useful for improving the dispersibility and strength of silica in applications such as tires.

Conventionally known methods for producing 3-mercaptopropylalkoxysilanes containing 3-mercaptopropyl groups include the following methods, but each has its own problems, and immediate countermeasures have been desired. .
1) As a method for producing a mercaptoalkylalkoxysilane containing 3-mercaptopropylalkoxysilane, a method based on a reaction in the presence of ammonia between a haloalkylalkoxysilane and thiourea is known (Japanese Patent Publication No. 50-7487, German Patent). Invention 3346910 specification, Japanese Patent Publication No. 4-16476 (patent documents 1-3)). However, in these methods, there is a problem that guanidine hydrochloride having a very bulky property is generated as a by-product, and disposal is difficult. The filterability has been improved by using various solvents, but polar solvents such as DMF are not only expensive, but they are not easy to separate from the target due to their high boiling point, and are required for separation. There was a problem that energy caused a rise in manufacturing costs. In recent years, solvents such as trichlorethylene have very large environmental problems and human toxicity problems.
2) A method of reacting haloalkylalkoxysilane with hydrogen sulfide gas in the presence of amines (Japanese Patent Publication No. 60-2312: Patent Document 4) is also known. However, high pressure conditions of 1 MPa or more are necessary, and there are problems in handling amines and toxic hydrogen sulfide gas, problems in handling facilities, and safety problems.
3) A method of reacting sodium methoxide (commercially available or prepared by reacting metallic sodium and methanol) with hydrogen sulfide gas and then reacting with 3-halopropylalkoxysilane is also known (UK Patent No. 1). No. 1102251, JP-A-4-261188, JP-A-8-291184, and JP-A-8-291185 (patent documents 5 to 8). JP-A-8-291185 also describes a method of reacting 3-halopropylalkoxysilane after preparing NaSH in the system by reacting Na ₂ S with hydrogen sulfide gas. .

  Here, if the above method is essentially considered, it eventually results in the reaction of NaSH prepared by some method with 3-halopropylalkoxysilane, but in any of these methods, There were various problems.

For example, anhydrous Na ₂ S, which is one of the raw materials, is generally not commercially available, and it is difficult to obtain it industrially at low cost, and even if it can be obtained, anhydrous Na _{2 S} Since S has the property of being deteriorated by oxygen, carbon dioxide, etc. in the air, the purity deteriorates and the yield of the target product decreases due to contact with air that cannot be substantially avoided when charging into the reactor. There is also a risk of it. Furthermore, even if it takes the method of dehydrating commercially available water-containing Na ₂ S by any method, not only is it time-consuming, but another step of synthesis (reaction with hydrogen sulfide gas) is required to obtain NaSH. Is very complicated.

  Moreover, even if it is prepared from sodium methoxide, there is anxiety that sodium methoxide has low long-term storage stability, and even if sodium methoxide is prepared from metallic sodium and hydrogen sulfide gas in the reactor, Since contact with moisture must be avoided very strictly, there is a problem that it is necessary to use metallic sodium which is very difficult to handle.

  In addition, any of the above methods must use a large amount of hydrogen sulfide gas, which is a gas that has great problems in terms of safety technology, toxicology, odor, and corrosivity. Therefore, not only is handling very difficult, but a large burden is required for safety measures in various facilities. In addition, for general companies, hydrogen sulfide gas is a relatively expensive raw material to be purchased, and the method of using it in large quantities leads to a rise in manufacturing costs and the problem that man-hours are required for loading and unloading cylinders. there were.

  In addition, about the method of preparing form NaSH which can be used for reaction directly from hydrous NaSH, ie, the dehydration method of hydrous NaSH, the method of heating hydrous NaSH generally on pressure reduction conditions, or heating on inert gas distribution conditions is the method. Conventionally known (JP-A-6-258503, JP-A-6-258502, JP-A-6-256005, JP-A-6-256003 (Patent Documents 9 to 12)).

  However, in any method, means for preventing NaSH that melts by heating during dehydration and adheres to the inner wall of the reactor from adhering to the wall (means for obtaining a form that can be easily taken out from the reactor). Since it was a special method mainly provided, there was a problem that strict operation was required for temperature control and pressure control in the dehydration process.

  In addition, according to the above-described method, there is a problem that it is difficult to operate and a dangerous process is required in practice, such as charging NaSH powder into the reactor in the middle of the process. Furthermore, since none of the methods uses a solvent, a special production facility such as an evaporator has to be used to stir the solidified NaSH inside the reactor, which is complicated and uncommon.

  Here, when water is contained in NaSH used as a reaction raw material for obtaining 3-mercaptopropylalkoxysilane, another raw material, 3-halopropylalkoxysilane, or the desired 3-mercaptopropylalkoxysilane, is obtained. Each of the alkoxy groups hydrolyzes with the water contained therein, so that a high-boiling siloxane oligomer or siloxane gel is produced as a by-product during the reaction, resulting in a decrease in yield or a decrease in purity. Therefore, it is more preferable that the reaction raw material NaSH does not contain water (close to an anhydrous state).

  From the above, the method 1) and 2) as well as the method 3), which is improved in some respects than the methods 1) and 2), still have problems, When obtaining NaSH, raw materials with physical properties that are particularly toxic or difficult to handle, such as hydrogen sulfide gas and metallic sodium, only by using inexpensive raw materials that are readily available on an industrial scale In addition, it can be carried out in a general synthesis facility under a mild reaction condition and with a simple operation, and then by using this NaSH, a 3-mercaptopropylalkoxysilane can be obtained in a high yield. As for the method, a good method has not been known yet, and an immediate solution has been desired.

Japanese Patent Publication No. 50-7487 German Patent Invention No. 3346910 Japanese Patent Publication No. 4-16476 Japanese Patent Publication No. 60-2312 British Patent No. 1102251 JP-A-4-261188 JP-A-8-291184 JP-A-8-291185 JP-A-6-258503 JP-A-6-258502 JP-A-6-256005 JP-A-6-256003

  The present invention has been made in view of the above circumstances, and in obtaining NaSH as a reaction raw material, hydrogen sulfide gas and sodium metal are typified only by the use of an inexpensive raw material that is easily available on an industrial scale. In particular, it is possible to carry out by simple operation under mild reaction conditions in a general synthesis facility with minimal use of raw materials with physical properties that are toxic or difficult to handle, and then use this NaSH 3-mercaptopropylalkoxysilane can be obtained in a high yield, and in addition, hydrogen sulfide gas, which is very problematic in terms of safety technology, toxicology, odor, and corrosivity, is completely eliminated. An object of the present invention is to provide a method for producing 3-mercaptopropylalkoxysilane which is not used or can be produced with only a minimum use.

  In order to achieve the above object, the inventors of the present invention have obtained an industrial scale for obtaining NaSH as a reaction raw material in a method of synthesizing 3-mercaptopropylalkoxysilane by reaction of NaSH and 3-halopropylalkoxysilane. By using raw materials that are easily available and inexpensive, use raw materials with physical properties that are particularly toxic or difficult to handle, such as hydrogen sulfide gas and metallic sodium. We intensively studied a method that can be carried out with a simple operation under mild reaction conditions in a typical synthesis facility. As a result, this includes readily available and inexpensive hydrous NaSH on an industrial scale, as well as alkoxysilanes or siloxanes having alkoxy groups, as well as general synthesis equipment and mild reaction conditions. By reacting by a method that can be carried out by a simple operation, water contained in the hydrous NaSH is hydrolyzed with alkoxysilane or siloxane having an alkoxy group, and NaSH is dehydrated by chemical removal, followed by 3-halopropyl. It has been found that by reacting with alkoxysilane, 3-mercaptopropylalkoxysilane can be obtained in high yield and the above object can be achieved.

  In addition, in the preparation of NaSH, it is not necessary to use hydrogen sulfide gas having various problems as described above. Further, in the reaction of NaSH and 3-halopropylalkoxysilane in the next step, hydrogen sulfide gas is used. It has been found that 3-mercaptopropylalkoxysilane can be produced by using no or a necessary minimum amount.

  Alcohols produced as a by-product during the preparation of NaSH (when the alkoxy group of the silicon compound having an alkoxy group is hydrolyzed by the water content of the hydrous NaSH) react with NaSH in the next step and 3-halopropylalkoxysilane. It was also found that this is a very efficient method because it is used as a reaction solvent, and thus the yield per unit volume is high.

  Furthermore, since the reaction mixture containing NaSH prepared by the above method can be handled in a slurry state without solidifying throughout the entire process, there is no possibility of causing a physical trouble in stirring the reaction mixture. In addition, in the case of conventional dehydration methods, hydrous NaSH may melt when exposed to heating conditions exceeding the melting point in the process of dehydration. Due to the nature, there may be a problem that the glass surface is damaged when the material of the container is a glass lining, but in the present invention, there is an advantage that such a problem does not occur. This has been made and the present invention has been made.

  Therefore, the present invention is characterized by reacting NaSH obtained through a step of reacting hydrous NaSH with an organosilicon compound having an alkoxy group and 3-halopropylalkoxysilane represented by the following general formula (1). A method for producing 3-mercaptopropylalkoxysilane represented by the following general formula (2) is provided.

X (CH ₂ ) ₃ SiR _n (OR ¹ ) _3-n (1)
HS (CH ₂ ) ₃ SiR _n (OR ¹ ) _3-n (2)
Wherein X is Cl, Br or I, R is the same or different monovalent hydrocarbon group having 1 to 6 carbon atoms, and R ¹ is the same or different. An alkyl group having 1 to 4 carbon atoms, and n represents an integer of 0 to 2.)

  According to the production method of the present invention, it is particularly toxic and difficult to handle as represented by hydrogen sulfide gas and metallic sodium only by using raw materials that are easily available and inexpensive on an industrial scale. The raw material NaSH can be obtained with mild reaction conditions and simple operation using a general synthesis facility, without using raw materials with various physical properties. By using this, 3-mercaptopropylalkoxysilane can be obtained. Can be obtained in a high yield, and in addition to safety technology, toxicology, odor, and its corrosiveness, hydrogen sulfide gas, which is a very serious problem, is not used at all or the minimum necessary It can be manufactured by using only.

Hereinafter, the present invention will be described in more detail.
In the present invention, a method for preparing NaSH (that is, dehydration step of hydrous NaSH) is performed by mixing hydrous NaSH and an organosilicon compound having an alkoxy group, and reacting water in hydrous NaSH with an organosilicon compound having an alkoxy group. It is carried out by letting. The essence of the reaction here is that water is chemically removed because water of crystallization in hydrous NaSH is subjected to a hydrolysis reaction with the alkoxy group of the organosilicon compound. More specifically, when water-containing NaSH and an organosilicon compound having an alkoxy group are mixed, a hydrolysis reaction represented by the following formula (5) occurs, so that the crystal water in the water-containing NaSH is chemically removed. (Here, SiOR ′ represents a silicon atom-bonded alkoxy group in an organosilicon compound having an alkoxy group, SiOH represents a silanol group, and R ′ is a monovalent organic group.)
H ₂ O + SiOR ′ → SiOH + R′OH (5)
Since silanol is subsequently dehydrated and condensed to be converted to siloxane, the chemical reaction in the dehydration step is eventually expressed by the following formula (6). (Here, SiOSi represents siloxane. R ′ is the same as above.)
H ₂ O + 2SiOR ′ → SiOSi + 2R′OH (6)

  In the following, the operation of the dehydration process will be described in more detail. In the dehydration process, flake-shaped water-containing NaSH is charged into a reaction vessel sufficiently substituted with an inert gas such as nitrogen, and then an organic compound having an appropriate amount of alkoxy groups. It is carried out by mixing the silicon compound and stirring under appropriate temperature conditions.

  Hydrous NaSH is usually marketed as a flaky solid and is a raw material that can be obtained industrially in large quantities at a low cost. The water content is generally commercially available, and is usually 10 to 40% by mass, particularly 20 to 30% by mass, based on the amount of flakes. In the present invention, if the moisture content is known in advance, it is only necessary to change the amount of alkoxysilane or alkoxy group-containing siloxane to an appropriate amount, and therefore any moisture content of the hydrous NaSH can be accommodated. The water content of NaSH prepared by the dehydration step is preferably 1% by mass or less, particularly preferably 0.5% by mass or less.

The organosilicon compound having an alkoxy group used in the present invention can be used in various forms and is basically not limited, but is preferably an alkoxy group represented by R ¹ O— (R ¹ is An alkoxysilane having 1 to 4 carbon atoms) or siloxane, more preferably an alkoxysilane having 4 to 3 alkoxy groups bonded to a silicon atom, or 3 to 2 alkoxy groups bonded to a silicon atom. Siloxanes having such constituents are desirable. In addition, in any of the alkoxysilane and the siloxane having an alkoxy group, when a group other than the alkoxy group is bonded to the silicon atom, the property of not reacting with NaSH, the property of not being affected by NaSH, and the target mercapto group Those that do not react are preferred. Specifically, a group other than the alkoxy group bonded to the silicon atom is preferably a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms.

As alkoxysilane, the following general formula (3)
SiR ² _m (OR ¹ ) _4-m (3)
(Wherein, R ¹ is the same as above, R ² is a monovalent hydrocarbon group such as an alkyl group having 1 to 6 carbon atoms, and may be the same or different. M represents 0 or 1) .)
Specific examples of such alkoxysilanes include tetramethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, n-hexyltrimethoxysilane, cyclopentyltrimethoxysilane. Cyclohexyltrimethoxysilane, tetraethoxysilane, methyltriethoxysilane, tetraisopropoxysilane, methyltriisopropoxysilane, and the like, and any alkoxysilane can be obtained on an industrial scale at low cost. Of these, those having a structure having four alkoxy groups are particularly preferred.

  In the present invention, when the target alkoxy group is a methoxy group, tetramethoxysilane and methyltrimethoxysilane are preferably used. When the target alkoxy group is an ethoxy group, tetraethoxysilane and methyltriethoxysilane are preferably used. preferable. The reason for this is that the molecular weight is small in the above examples, the amount of alkoxysilane necessary to chemically remove moisture in the system can be reduced as much as possible, and the reactivity with moisture is relatively good. And it is economically advantageous because it is industrially inexpensive. Theoretically, an alkoxysilane having 1 or 2 alkoxy groups can also be used, but generally, the amount necessary for removing water is smaller than that of 4 or 3 alkoxysilanes. Large amounts may be economically disadvantageous.

  Specific examples of the siloxane having an alkoxy group include hexamethoxydisiloxane, hexaethoxydisiloxane, octamethoxytrisiloxane, decamethoxytetrasiloxane, hexamethoxycyclotrisiloxane, hexaethoxycyclotrisiloxane, and octamethoxycyclotetrasiloxane. , Methylpentamethoxydisiloxane, 1,1′-dimethyl-tetramethoxydisiloxane, 1,1-dimethyl-tetramethoxydisiloxane, 1,1,1-trimethyltrimethoxysiloxane, etc., trimethoxysilyl group, Examples include siloxanes having a weight average molecular weight of 200 to 100,000, particularly 200 to 2,000 having a triethoxysilyl group, a methyldimethoxysilyl group or a methyldiethoxysilyl group as a constituent element. It is.

  The amount of the alkoxysilane or the siloxane having an alkoxy group is used because the water in the hydrous NaSH is stoichiometrically completely removed by the hydrolysis reaction with the alkoxy group of the alkoxysilane or the siloxane having an alkoxy group. The required amount is preferable, and more preferably, it is desirable to use an alkoxysilane having an alkoxy group having an equivalent to about 2 equivalents or a siloxane having an alkoxy group with respect to the water in the hydrous NaSH. If it is too much, it may not only cause unnecessary impurities, but it may be economically disadvantageous. If it is too little, the water in the hydrated NaSH may not be sufficiently removed. A certain 3-mercaptopropylalkoxysilane may be hydrolyzed to reduce the yield.

  In the present invention, when the same alcohols as the alcohols by-produced by the hydrolysis reaction of hydrous NaSH and alkoxysilane or siloxane having an alkoxy group are mixed in advance as a reaction solvent, NaSH is relatively good for alcohols. Since it melt | dissolves, the stirring property of a reaction mixture and the efficiency of a hydrolysis reaction can be improved. In addition, for the purpose of improving the stirring property of the reaction mixture, it is possible to use an organic solvent different from the above alcohols, or to use this in combination with the above alcohols. Solvents and aromatic solvents may reduce the efficiency of the dehydration step by hydrolysis reaction.

As a reaction solvent in the dehydration step, the following general formula (4)
R ¹ OH (4)
(In the formula, R ¹ is an alkyl group having 1 to 4 carbon atoms.)
Preferred examples of such alcohols include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, isobutyl alcohol, tert-butyl alcohol. Etc. In particular, when the alkoxysilane or siloxane having an alkoxy group to be used and the target alkoxy group are methoxy groups, methyl alcohol is preferable, and when the alkoxy group is ethoxy group, ethyl alcohol is preferable.

  The amount of alcohol used as a reaction solvent is not particularly limited, but preferably the total amount of alkoxysilane or alcohol by-produced by hydrolysis of siloxane having an alkoxy group is the same as that of 3-halopropylalkoxysilane in the next step. The amount is preferably such that the above reaction step occurs sufficiently and the stirring property can be sufficiently secured. Specifically, the amount is preferably such that the concentration of NaSH is 10 to 40% by mass in total with alcohols by-produced by hydrolysis of alkoxysilane or siloxane having an alkoxy group. If the amount exceeds 40% by mass, stirring of the reaction mixture may be difficult. If it is less than 10% by mass, the yield per unit volume decreases, which may be economically disadvantageous.

  In addition, when an alkoxysilane having an alkoxy group different from the alkoxy group of 3-mercaptopropylalkoxysilane, which is the target product, or a siloxane having an alkoxy group, and an alcohol as a reaction solvent are used, In the reaction with pyralkoxysilane, the purity of the target product may be deteriorated due to the exchange reaction of the alkoxy group. In such a case, it is necessary to replace alcohols by-produced after the dehydration step with alcohols corresponding to the alkoxy group of 3-mercaptopropylalkoxysilane, which is the target product. -It is desirable to select an alkoxysilane having the same alkoxy group as the alkoxy group of mercaptopropylalkoxysilane or a siloxane having an alkoxy group, and an alcohol as a reaction solvent.

  In the dehydration step, there is no particular limitation on the method of adding alkoxysilane or siloxane having an alkoxy group, but it may be dropped into a mixture of hydrous NaSH and a reaction solvent every time or may be added together with these. Good.

  In the dehydration step, the above alkoxysilane or siloxane having an alkoxy group is newly converted into siloxanes having a high boiling point by a hydrolysis reaction with water in the water-containing NaSH. At this time, depending on the number of alkoxy groups and the selected substrate, it becomes a fine granular siloxane gel and precipitates in the reaction mixture or becomes a viscous liquid siloxane oil. At this time, it is preferable to consider the selection and use amount of the substrate so that siloxanes having a boiling point close to that of the target product and difficult to separate are not by-produced. In the case where the by-product siloxane is a fine granular siloxane gel, it can be separated by an operation such as filtration or centrifugation in the post-treatment stage of the subsequent reaction mixture. Moreover, when it becomes a high boiling-point liquid like a siloxane oil, it can be fractionated as a residue in a distillation pot liquid in the distillation refinement | purification stage of a target object.

  The flaky water-containing NaSH is partially or completely dissolved in alcohols added as a reaction solvent and alcohols by-produced by hydrolysis of alkoxysilane or siloxane having an alkoxy group. As the hydrolysis reaction proceeds, it gradually dehydrates. At this time, depending on the type of the selected alkoxysilane or siloxane having an alkoxy group, as a hydrolysis reaction proceeds, a siloxane gel product by-produced in the reaction mixture gradually precipitates. However, this gel substance has a fine particle shape and does not become a large mass, and the reaction mixture becomes a slurry state that can be stirred. For this reason, it can progress to the reaction process with 3-halopropyl alkoxysilane of the following process with the state. After the dehydration step, the siloxane gel product may be removed by filtration or centrifugation, but in order to simplify the process, the siloxane gel product is not removed and the next step is continued. It is preferable to proceed to the reaction step with 3-halopropylalkoxysilane and remove the sodium halide by-produced in the step together by removing it by filtration or centrifugation. Further, when separating the siloxane gel product and sodium halide in the filter cake, a measure such as washing the filter cake with water can be taken.

  The temperature condition of the dehydration step is generally carried out at 0 to 200 ° C. If it is too low, the hydrolysis reaction may be delayed and the dehydration efficiency may be reduced. If it is too high, NaSH may be altered, and unnecessary energy loss may occur. The condition range of 10 to 100 ° C. is preferably selected, and more preferably, the boiling point temperature of the alcohol used from 10 ° C. is the upper limit. In addition, when exothermic NaSH and alcohols as a reaction solvent are mixed, when alkoxysilane or siloxane having an alkoxy group and hydrous NaSH are mixed, and during hydrolysis reaction, mild heat generation may occur.

  As the pressure condition, generally, the atmospheric pressure condition is selected, and the atmospheric pressure condition is necessary and sufficient. However, if necessary, the pressure condition or the reduced pressure condition may be used. The reaction time can be arbitrarily selected from 1 to 200 hours and is not particularly limited, but in general, the dehydration reaction can be completed in about 1 to 10 hours. The reaction atmosphere is preferably in a state where moisture and air are sufficiently removed by an inert gas such as nitrogen or argon.

  In the present invention, the synthesis of the target 3-mercaptopropylalkoxysilane is performed by mixing and reacting NaSH obtained by the dehydration step with 3-halopropylalkoxysilane represented by the following general formula (1). Is implemented.

X (CH ₂ ) ₃ SiR _n (OR ¹ ) _3-n (1)
Wherein X is Cl, Br or I, R is the same or different monovalent hydrocarbon group having 1 to 6 carbon atoms, and R ¹ is the same or different. An alkyl group having 1 to 4 carbon atoms, and n represents an integer of 0 to 2.)
In the above formula (1), X can be exemplified by Cl, Br or I, and R and R ¹ are methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group and isobutyl group, respectively. And a tert-butyl group.

Specific examples of such 3-halopropylalkoxysilane include
3-chloropropyltrimethoxysilane,
3-chloropropyltriethoxysilane,
3-chloropropyltri-n-propoxysilane,
3-chloropropyltriisopropoxysilane,
3-chloropropyltri-n-butoxysilane,
3-chloropropyltrisec-butoxysilane,
3-chloropropyltriisobutoxysilane,
3-chloropropylmethyldimethoxysilane,
3-chloropropylmethyldiethoxysilane,
3-chloropropylmethyldi n-propoxysilane,
3-chloropropylmethyldiisopropoxysilane,
3-chloropropylmethyldi n-butoxysilane,
3-chloropropylmethyldisec-butoxysilane,
3-chloropropylmethyldiisobutoxysilane,
3-chloropropylethyldimethoxysilane,
3-chloropropylethyldiethoxysilane,
3-chloropropylethyldi n-propoxysilane,
3-chloropropylethyl diisopropoxysilane,
3-chloropropylethyldi n-butoxysilane,
3-chloropropylethyl disec-butoxysilane,
3-chloropropylethyl diisobutoxysilane,
3-chloropropyldimethylmethoxysilane,
3-chloropropyldimethylethoxysilane,
3-chloropropyldimethyl n-propoxysilane,
3-chloropropyldimethylisopropoxysilane,
3-chloropropyldimethyl n-butoxysilane,
3-chloropropyldimethyl sec-butoxysilane,
3-chloropropyldimethylisobutoxysilane,
3-chloropropylmethylethylmethoxysilane,
3-chloropropylmethylethylethoxysilane,
3-chloropropylmethylethyl n-propoxysilane,
3-chloropropylmethylethyl isopropoxysilane,
3-chloropropylmethylethyl n-butoxysilane,
3-chloropropylmethylethyl sec-butoxysilane,
3-chloropropylmethylethyl isobutoxysilane,
3-bromopropyltrimethoxysilane,
3-bromopropyltriethoxysilane,
3-bromopropyltri-n-propoxysilane,
3-bromopropyltriisopropoxysilane,
3-bromopropyltri-n-butoxysilane,
3-bromopropyltrisec-butoxysilane,
3-bromopropyltriisobutoxysilane,
3-bromopropylmethyldimethoxysilane,
3-bromopropylmethyldiethoxysilane,
3-bromopropylmethyldi n-propoxysilane,
3-bromopropylmethyldiisopropoxysilane,
3-bromopropylmethyldi n-butoxysilane,
3-bromopropylmethyldisec-butoxysilane,
3-bromopropylmethyldiisobutoxysilane,
3-bromopropylethyldimethoxysilane,
3-bromopropylethyldiethoxysilane,
3-bromopropylethyldi n-propoxysilane,
3-bromopropylethyl diisopropoxysilane,
3-bromopropylethyldi n-butoxysilane,
3-bromopropylethyl disec-butoxysilane,
3-bromopropylethyl diisobutoxysilane,
3-bromopropyldimethylmethoxysilane,
3-bromopropyldimethylethoxysilane,
3-bromopropyldimethyl n-propoxysilane,
3-bromopropyldimethylisopropoxysilane,
3-bromopropyldimethyl n-butoxysilane,
3-bromopropyldimethyl sec-butoxysilane,
3-bromopropyldimethylisobutoxysilane,
3-bromopropylmethylethylmethoxysilane,
3-bromopropylmethylethylethoxysilane,
3-bromopropylmethylethyl n-propoxysilane,
3-bromopropylmethylethyl isopropoxysilane,
3-bromopropylmethylethyl n-butoxysilane,
3-bromopropylmethylethyl sec-butoxysilane,
3-bromopropylmethylethyl isobutoxysilane,
3-iodopropyltrimethoxysilane,
3-iodopropyltriethoxysilane,
3-iodopropyltri-n-propoxysilane,
3-iodopropyltriisopropoxysilane,
3-iodopropyltri n-butoxysilane,
3-iodopropyltri-sec-butoxysilane,
3-iodopropyltriisobutoxysilane,
3-iodopropylmethyldimethoxysilane,
3-iodopropylmethyldiethoxysilane,
3-iodopropylmethyldi n-propoxysilane,
3-iodopropylmethyldiisopropoxysilane,
3-iodopropylmethyldi n-butoxysilane,
3-iodopropylmethyldisec-butoxysilane,
3-iodopropylmethyldiisobutoxysilane,
3-iodopropylethyldimethoxysilane,
3-iodopropylethyldiethoxysilane,
3-iodopropylethyldi n-propoxysilane,
3-iodopropylethyl diisopropoxysilane,
3-iodopropylethyldi n-butoxysilane,
3-iodopropylethyldisec-butoxysilane,
3-iodopropylethyl diisobutoxysilane,
3-iodopropyldimethylmethoxysilane,
3-iodopropyldimethylethoxysilane,
3-iodopropyldimethyl n-propoxysilane,
3-iodopropyldimethylisopropoxysilane,
3-iodopropyldimethyl n-butoxysilane,
3-iodopropyldimethyl sec-butoxysilane,
3-iodopropyldimethylisobutoxysilane,
3-iodopropylmethylethylmethoxysilane,
3-iodopropylmethylethylethoxysilane,
3-iodopropylmethylethyl n-propoxysilane,
3-iodopropylmethylethyl isopropoxysilane,
3-iodopropylmethylethyl n-butoxysilane,
3-iodopropylmethylethyl sec-butoxysilane,
Examples include 3-iodopropylmethylethylisobutoxysilane.

X is preferably Cl from the standpoint of availability of raw materials and cost. As the silane coupling agent, trialkoxysilane type or dialkoxysilane type is generally used. In this case, it is preferable that R = methyl group, R ¹ = methyl group or ethyl group.

  The use ratio of NaSH and the above-mentioned 3-halopropylalkoxysilane is not particularly limited, but generally 3-halopropylalkoxysilane is 0.8 to 1.2 with respect to 1 mol of anhydrous NaSH. The amount is preferably such that it is 0.9 to 1.0 mol. If the amount of 3-halopropylalkoxysilane is less than the above amount, the amount of unreacted NaSH residue increases. If the reaction mixture remains alkaline due to its influence, 3 in 3-mercaptopropylalkoxysilane distilled during distillation purification. -Not only may there be an excessive phenomenon that alcohol is eliminated from mercaptopropylalkoxysilane and mixed with cyclic components, but filterability is poor when the by-product sodium halide is filtered off. May end up. On the other hand, if there is more 3-halopropylalkoxysilane than the above amount, the unreacted 3-halopropylalkoxysilane residue increases in the reaction mixture, and there is not much difference in boiling point between it and the target product. In this case, separation may be difficult, and the yield of a high-purity target fraction may be reduced.

  As a mixing method of NaSH and 3-halopropylalkoxysilane, 3-halopropylalkoxysilane is generally added dropwise to a reaction mixture containing NaSH. However, when the siloxane gel product by-produced in the dehydration step is removed from the reaction mixture containing NaSH to form a solution, it is possible to feed in a slurry state containing the siloxane gel product, or liquid in the dehydration step. When this siloxane oil is by-produced, a method of dropping a reaction mixture containing NaSH into 3-halopropylalkoxysilane can be taken. The dripping method is to press-fit into the reaction vessel under a sealed / pressurized condition, but after dropping the entire amount of raw materials under an open / atmospheric pressure condition, the reactor is put into a sealed / pressurized condition. Is also possible.

  Regarding the reaction temperature, pressure, time, and dropping method in the reaction of NaSH and 3-halopropylalkoxysilane, conventionally known conditions can be arbitrarily selected. However, the reaction conditions of NaSH and 3-halopropylalkoxysilane are as follows. More specifically, the reaction temperature (drip / ripening) is preferably 50 to 150 ° C., the pressure is atmospheric pressure to 2.0 MPa, and the reaction time is arbitrarily selected within the range of 1 to 100 hours. The reactor may be sealed or pressurized or open under atmospheric pressure. However, sealed / pressurized conditions are more preferable for improving the reaction yield. In addition, it is necessary to select the type of the reactor to be used depending on the pressure conditions to be applied, and it is preferable to use a corresponding pressure vessel (autoclave or the like) in the sealed / pressurized conditions.

  In addition, NaSH in the present invention is prepared without using any hydrogen sulfide gas as compared with a conventionally known method. Even in the reaction with 3-halopropylalkoxysilane, no hydrogen sulfide gas is used. The reaction with 3-halopropylalkoxysilane can be carried out without use. This is a great advantage of the present invention.

  In the present invention, as described above, the target product can be synthesized without using any hydrogen sulfide gas. However, in order to reduce by-products and slightly increase the yield, a conventionally known method can be used. As described above, it is possible to adopt a method in which 3-halopropylalkoxysilane is dropped after hydrogen sulfide gas is blown into the reaction mixture containing NaSH to an arbitrary pressure under sealed and pressurized conditions. Even in this case, the amount of hydrogen sulfide gas used is very small as compared with a conventionally known method, and there is an advantage that the necessary minimum amount is sufficient.

  The 3-mercaptopropylalkoxysilane obtained by the present invention is represented by the following general formula (2).

HS (CH ₂ ) ₃ SiR _n (OR ¹ ) _3-n (2)
Wherein R is the same or different monovalent hydrocarbon group having 1 to 6 carbon atoms, and R ¹ is the same or different alkyl group having 1 to 4 carbon atoms. And R and R ¹ may be the same as those described above, and n represents an integer of 0 to 2.)
As such 3-mercaptopropylalkoxysilane, specifically,
3-mercaptopropyltrimethoxysilane,
3-mercaptopropyltriethoxysilane,
3-mercaptopropyltri-n-propoxysilane,
3-mercaptopropyl triisopropoxysilane,
3-mercaptopropyltri-n-butoxysilane,
3-mercaptopropyltri-sec-butoxysilane,
3-mercaptopropyl triisobutoxysilane,
3-mercaptopropylmethyldimethoxysilane,
3-mercaptopropylmethyldiethoxysilane,
3-mercaptopropylmethyldi-n-propoxysilane,
3-mercaptopropylmethyldiisopropoxysilane,
3-mercaptopropylmethyldi-n-butoxysilane,
3-mercaptopropylmethyldisec-butoxysilane,
3-mercaptopropylmethyldiisobutoxysilane,
3-mercaptopropylethyldimethoxysilane,
3-mercaptopropylethyldiethoxysilane,
3-mercaptopropylethyldi n-propoxysilane,
3-mercaptopropylethyl diisopropoxysilane,
3-mercaptopropylethyldi n-butoxysilane,
3-mercaptopropylethyl disec-butoxysilane,
3-mercaptopropylethyl diisobutoxysilane,
3-mercaptopropyldimethylmethoxysilane,
3-mercaptopropyldimethylethoxysilane,
3-mercaptopropyldimethyl n-propoxysilane,
3-mercaptopropyldimethylisopropoxysilane,
3-mercaptopropyldimethyl n-butoxysilane,
3-mercaptopropyldimethyl sec-butoxysilane,
3-mercaptopropyldimethylisobutoxysilane,
3-mercaptopropylmethylethylmethoxysilane,
3-mercaptopropylmethylethylethoxysilane,
3-mercaptopropylmethylethyl n-propoxysilane,
3-mercaptopropylmethylethyl isopropoxysilane,
3-mercaptopropylmethylethyl n-butoxysilane,
3-mercaptopropylmethylethyl sec-butoxysilane,
Examples include 3-mercaptopropylmethylethylisobutoxysilane. Among these, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropylmethyldiethoxysilane are general-purpose compounds as silane coupling agents, It is an industrially important compound.

  After completion of the reaction between NaSH and 3-halopropylalkoxysilane, by-product sodium halide is mixed in the reaction solution as a salt in the form of fine particles. To separate the salt from the reaction solution. Further, after separating the salt, any solvent selected from alcohols, aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as n-hexane and isooctane, and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane By washing the salt with, the recovery rate of the target product can be improved. In addition, as described above, when a siloxane gel product is by-produced in the NaSH synthesis (dehydration step) and is not separated and removed after the dehydration step, it is separated and removed together during the above-described sodium halide separation. can do. Furthermore, by washing the separated cake with water, it is possible to dissolve the sodium halide and separate it from the siloxane gel.

  Next, the solvent is distilled off from the reaction solution obtained by separating solids such as salt and siloxane gel, and concentrated, and then 3-mercaptopropylalkoxysilane is purified and recovered with high purity by a general distillation method. Can do. Preferably, distillation operation under reduced pressure conditions is desirable. During the distillation operation, if the reaction mixture is alkaline, alcohol may be eliminated from the target product to cause a side reaction that forms a cyclized product. Therefore, hydrogen chloride, acetic acid, formic acid, succinic acid, benzoic acid, citric acid, Measures such as neutralizing the reaction solution by adding acids such as acids, dodecylbenzenesulfonic acid, phthalic acid, and reagents that generate hydrogen chloride (halogenated hydrocarbons, chlorosilanes, acid chlorides, etc.) You can also. In addition, even if the purity of the target product is lower than the desired value due to the by-product of the cyclic product, an appropriate amount for the cyclic product of the alcohol corresponding to the alkoxy group of the target product is determined. If the distillate is added later to the distillation fraction, the cyclic product is easily converted back to the target product, so that high purity can be achieved without any problem.

  The atmosphere for carrying out the method of the present invention is preferably an inert gas atmosphere such as nitrogen gas throughout all the steps. NaSH has the property of being denatured by oxygen and carbon dioxide in the air, and NaSH itself has deliquescent properties and is easy to absorb moisture, so it is easy to take in moisture in the air. This leads to a decrease in the yield of the target product. Moreover, since the raw material and the target alkoxysilane have the property of reacting with water and hydrolyzing, mixing of water is not preferable.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.

[Example 1]
A 500 mL autoclave made of stainless steel and equipped with a stirrer, a thermometer, a safety valve, a pressure gauge, and an injection nozzle was prepared, and the inside was sufficiently purged with nitrogen.
In this autoclave, 80 g of flaky water-containing NaSH (water content: about 26.3% (1.16 mol), NaSH: about 72% (1.03 mol)) and 112 g of methyl alcohol were charged. The internal temperature rose from 27 ° C. to 31 ° C. due to dissolution of NaSH. Next, 96 g (0.63 mol) of tetramethoxysilane was added dropwise with stirring under normal pressure conditions. At this time, the inside of the system was brought to atmospheric pressure condition through the pressure equalizing pipe of the dropping pipe, and the end of the open part was sealed with nitrogen gas. The internal temperature gradually increased with the dropwise addition of tetramethoxysilane. When tetramethoxysilane was added dropwise over about 1 hour, the reaction temperature rose to 30 to 40 ° C. In the reaction solution, a white, fine-grained siloxane gel was gradually deposited and became a slurry. After completion of the dropping, the autoclave was sealed and heated to 70 ° C. (pressure was 0.06 to 0.07 MPa), and aged for 2 hours.

  Next, under conditions of 70 ° C. and 0.06 MPa, 203 g (1.02 mol) of 3-chloropropyltrimethoxysilane was pressed into the autoclave for about 2 hours with a diaphragm metering pump. The pressure gradually increased to 0.13 MPa. Subsequently, the mixture was aged for 17 hours at 70 ° C. to complete the reaction (confirmation of disappearance of 3-chloropropyltrimethoxysilane). The pressure slowly increased to 0.18 MPa. At this time, when the composition of the reaction solution was examined, the 3-mercaptopropyltrimethoxysilane dimer (bis), which should be produced as a by-product if water exists in the system, was compared with the target 3-mercaptopropyltrimethoxysilane. The amount of (3-mercaptopropyl) tetramethoxydisiloxane was a trace amount. Therefore, according to the method of the present invention, it is confirmed that NaSH obtained through a dehydration step by reaction with tetramethoxysilane from hydrous NaSH is almost anhydrous, and that the dehydration by this step can be carried out sufficiently effectively. I was able to. Then, it cooled to 30 degreeC vicinity and purged the pressure.

  Further, 1.2 g of acetic acid was added to neutralize the reaction solution, and by-product sodium chloride and siloxane gel were removed by pressure filtration. Further, the sodium chloride and siloxane gel material separated by filtration were washed with 150 g of methanol, and the washing solution was added to the filtrate. Subsequently, as a result of distillation operation, 164 g (yield 82%) of 3-mercaptopropyltrimethoxysilane was obtained.

  By the method of the present invention, anhydrous NaSH can be obtained from water-containing NaSH, which is industrially available at low cost, using tetramethoxysilane, which is industrially available at low cost, in a gentle and simple manner. Even without this, 3-mercaptopropyltrimethoxysilane could be produced.

[Example 2]
A 500 mL autoclave made of stainless steel and equipped with a stirrer, a thermometer, a safety valve, a pressure gauge, and an injection nozzle was prepared, and the inside was sufficiently purged with nitrogen.
In this autoclave, 80 g of flaky water-containing NaSH (water content: about 26.3% (1.16 mol), NaSH: about 72% (1.03 mol)) and 112 g of methyl alcohol were charged. The internal temperature rose from 27 ° C. to 31 ° C. due to dissolution of NaSH. Next, 96 g (0.63 mol) of tetramethoxysilane was added dropwise with stirring under normal pressure conditions. At this time, the inside of the system was brought to atmospheric pressure condition through the pressure equalizing pipe of the dropping pipe, and the end of the open part was sealed with nitrogen gas. The internal temperature gradually increased with the dropwise addition of tetramethoxysilane. When tetramethoxysilane was added dropwise over about 1 hour, the reaction temperature rose to 30 to 40 ° C. In the reaction solution, a white, fine-grained siloxane gel was gradually deposited and became a slurry. After completion of the dropping, the autoclave was sealed and heated to 70 ° C. (pressure was 0.06 to 0.07 MPa), and aged for 2 hours.

  Next, under conditions of 70 ° C. and 0.06 MPa, 203 g (1.02 mol) of 3-chloropropyltrimethoxysilane was pressed into the autoclave for about 2 hours with a diaphragm metering pump. The pressure gradually increased to 0.13 MPa. Subsequently, the reaction temperature was raised to 100 ° C. (pressure became 0.36 to 0.37 MPa), and then aged for 7 hours to complete the reaction (confirmation of disappearance of 3-chloropropyltrimethoxysilane) . The pressure was 0.36 to 0.37 MPa. At this time, when the composition of the reaction solution was examined, the 3-mercaptopropyltrimethoxysilane dimer (bis), which should be produced as a by-product if water exists in the system, was compared with the target 3-mercaptopropyltrimethoxysilane. The amount of (3-mercaptopropyl) tetramethoxydisiloxane was a trace amount. Therefore, according to the method of the present invention, it is confirmed that NaSH obtained through a dehydration step by reaction with tetramethoxysilane from hydrous NaSH is almost anhydrous, and that the dehydration by this step can be carried out sufficiently effectively. I was able to. Then, it cooled to 30 degreeC vicinity and purged the pressure.

  Furthermore, 2.4 g of succinic acid was added to neutralize the reaction solution, and then by-product sodium chloride and siloxane gel were removed by pressure filtration. Further, the sodium chloride and siloxane gel material separated by filtration were washed with 150 g of methanol, and the washing solution was added to the filtrate. Next, as a result of distillation operation, 168 g (yield 84%) of 3-mercaptopropyltrimethoxysilane was obtained.

[Example 3]
A 500 mL autoclave made of stainless steel and equipped with a stirrer, a thermometer, a safety valve, a pressure gauge, and an injection nozzle was prepared, and the inside was sufficiently purged with nitrogen.
In this autoclave, 80 g of flaky water-containing NaSH (water content: about 26.3% (1.16 mol), NaSH: about 72% (1.03 mol)) and 112 g of methyl alcohol were charged. The internal temperature rose from 27 ° C. to 32 ° C. due to dissolution of NaSH. Next, 96 g (0.63 mol) of tetramethoxysilane was added dropwise with stirring under normal pressure conditions. At this time, the inside of the system was brought to atmospheric pressure condition through the pressure equalizing pipe of the dropping pipe, and the end of the open part was sealed with nitrogen gas. The internal temperature gradually increased with the dropwise addition of tetramethoxysilane. When tetramethoxysilane was added dropwise over about 1 hour, the reaction temperature rose to 30 to 40 ° C. In the reaction solution, a white, fine-grained siloxane gel was gradually deposited and became a slurry. After completion of the dropping, the autoclave was sealed and heated to 70 ° C. (pressure was 0.06 to 0.07 MPa), and aged for 2 hours.

  Further, after cooling the autoclave to 30 ° C. or less, a small amount of hydrogen sulfide gas was injected into the system from a cylinder until the pressure reached 0.05 MPa at 27 ° C. while stirring. Next, the temperature was raised to 70 ° C. with a mantle heater (the pressure became 0.13 MPa). Thereafter, 186 g (1.02 mol) of 3-chloropropylmethyldimethoxysilane was press-fitted into the autoclave for about 2 hours with a diaphragm metering pump, and the pressure gradually increased to 0.20 MPa with the amount of press-fitting. . Subsequently, after raising the temperature to 100 ° C. (pressure became 0.37 MPa), the reaction was completed by aging for 4 hours (confirmation of disappearance of 3-chloropropylmethyldimethoxysilane). The pressure slowly increased to 0.40 MPa. At this time, when the composition of the reaction solution was examined, the 3-mercaptopropylmethyldimethoxysilane dimer (bis), which should be formed as a by-product if water exists in the system, was compared with the target 3-mercaptopropylmethyldimethoxysilane. The amount of (3-mercaptopropyl) dimethyldimethoxydisiloxane was a trace amount. Therefore, according to the method of the present invention, it is confirmed that NaSH obtained through a dehydration step by reaction with tetramethoxysilane from hydrous NaSH is almost anhydrous, and that the dehydration by this step can be carried out sufficiently effectively. I was able to. It was also confirmed that hydrogen sulfide gas can be used in the minimum necessary amount. Then, it cooled to 30 degreeC vicinity and purged the pressure.

  Subsequently, 1.2 g of acetic acid was added to neutralize the reaction solution, and then by-product sodium chloride and siloxane gel were removed by pressure filtration. Further, the sodium chloride and siloxane gel material separated by filtration were washed with 150 g of methanol, and the washing solution was added to the filtrate. Then, as a result of distillation operation, 164 g (yield 89%) of 3-mercaptopropylmethyldimethoxysilane was obtained.

[Example 4]
A reaction was carried out in the same manner as in Example 3 except that 203 g (1.02 mol) of 3-chloropropyltrimethoxysilane was used instead of 186 g (1.02 mol) of 3-chloropropylmethyldimethoxysilane. As a result of the final distillation operation through the same reaction process, 180 g (yield 90%) of 3-mercaptopropyltrimethoxysilane was obtained.

Claims (10)

NaSH obtained through a step of reacting hydrous NaSH with an organosilicon compound having an alkoxy group and 3-halopropylalkoxysilane represented by the following general formula (1) are reacted, and the following general formula (2 The manufacturing method of 3-mercaptopropyl alkoxysilane shown by this.
X (CH ₂ ) ₃ SiR _n (OR ¹ ) _3-n (1)
HS (CH ₂ ) ₃ SiR _n (OR ¹ ) _3-n (2)
Wherein X is Cl, Br or I, R is the same or different monovalent hydrocarbon group having 1 to 6 carbon atoms, and R ¹ is the same or different. An alkyl group having 1 to 4 carbon atoms, and n represents an integer of 0 to 2.) The 3-mercaptopropylalkoxy according to claim 1, wherein the organosilicon compound having an alkoxy group is an alkoxysilane or siloxane having an alkoxy group represented by R ¹ O— (R ¹ is the same as above). A method for producing silane. The method for producing 3-mercaptopropylalkoxysilane according to claim 2, wherein the organosilicon compound having an alkoxy group is an alkoxysilane represented by the following general formula (3).
SiR ² _m (OR ¹ ) _4-m (3)
(Wherein R ¹ is the same as above, R ² is a monovalent hydrocarbon group having 1 to 6 carbon atoms, and may be the same or different. M represents 0 or 1) 3. The organosilicon compound having an alkoxy group is a siloxane in which two or three alkoxy groups represented by R ¹ O— (R ¹ is the same as above) are bonded to a silicon atom. A method for producing 3-mercaptopropylalkoxysilane. The 3-mercaptopropyl according to claim 1, wherein R ¹ in the formulas (1) and (2) is a methyl group, and the organosilicon compound having an alkoxy group is tetramethoxysilane or methyltrimethoxysilane. A method for producing alkoxysilane. The 3-mercaptopropyl according to claim 1, wherein R ¹ in the formulas (1) and (2) is an ethyl group, and the organosilicon compound having an alkoxy group is tetraethoxysilane or methyltriethoxysilane. A method for producing alkoxysilane. The method for producing 3-mercaptopropylalkoxysilane according to any one of claims 1 to 6, wherein an alcohol represented by the following general formula (4) is used as a reaction solvent.
R ¹ OH (4)
(In the formula, R ¹ is an alkyl group having 1 to 4 carbon atoms.) The R ¹ in the formulas (1) and (2) is a methyl group, the organosilicon compound has a methoxy group, and methyl alcohol is used as a reaction solvent. A method for producing mercaptopropylalkoxysilane. The R ¹ in the formulas (1) and (2) is an ethyl group, the organosilicon compound has an ethoxy group, and ethyl alcohol is used as a reaction solvent. A method for producing mercaptopropylalkoxysilane. X in Formula (1) is Cl, The manufacturing method of 3-mercaptopropyl alkoxysilane of any one of Claim 1 thru | or 9 characterized by the above-mentioned.