JP4574875B2 - A solvent recovery and regeneration method for producing a silicon compound having a hydrolyzable group. - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for recovering and regenerating an organic solvent used for producing a silicon compound having a mercapto group and a hydrolyzable group such as 3-mercaptopropylalkoxysilane useful as a silane coupling agent.
[0002]
[Prior art]
As a method for producing a silicon compound having a mercapto group or hydrolyzable group in the molecule, for example, JP-A-8-291185 discloses an alkali metal hydride and a general formula X (CH ₂ ) ₃ Si (OR) _a R _3-a (X represents Cl or Br, R represents a methyl group, an ethyl group or a propyl group, which may be the same or different. A represents an integer of 1, 2 or 3. ) In the presence of excess hydrogen sulfide in a sealed state under pressure and high yield of mercaptoalkoxysilane that suppresses by-product formation of sulfide compounds under mild conditions. The production method obtained at a rate is described.
[0003]
[Problems to be solved by the invention]
However, in this production method, various impurities and the like are mixed in the solvent recovered in the purification process, so that it is difficult to reuse it as it is. There was a problem of accelerating the damage.
[0004]
In order to carry out industrial mass production, it is necessary to establish a method for treating the recovered solvent and to reduce the burden on post-treatment. Preferably, it is necessary to reuse the recovered solvent to reduce the manufacturing cost and consider the environmental load.
The present invention is a solvent recovery / regeneration that can reduce the manufacturing cost by reusing a solvent recovered during the purification from the production of a silicon compound having a mercapto group or hydrolyzable group such as 3-mercaptopropylalkoxysilane. It aims to provide a method.
[0005]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have found that the components contained in the recovered solvent are the respective reaction reagents used in the reaction and their decomposition products, and that each reaction reagent is alkaline. The siloxanes are hydrolyzed to produce siloxanes, and when the solvent is distilled off, the siloxanes remain as distillation residues, and the present invention has been completed.
[0006]
The present invention provides: (1) in methanol, the hydrolyzable group to produce at least one comprising a silicon compound, methanol recovered when purifying by distillation, treated with water and a base, to distillation (2) A silicon compound containing at least one hydrolyzable group is represented by the formula (I)
[Formula 4]
(In formula, X < ₁ > -X < ₃ > may be the same or different, respectively, A hydrogen atom, a methyl group, an ethyl group, a propyl group, a phenyl group, a C1-C12 alkoxy group, a halogen atom, an amino group. , Dimethylamino group, diethylamino group, butylamino group, dibutylamino group, phenylamino group, diphenylamino group, acetoxy group, pityloyloxy group or carboxyl group , at least one of which represents a hydrolyzable group, R ₁ is a single bond or a methylene group, an ethylene group, a solvent recovery and recycling method according to (1) that it is a silicon compound represented by.) representing the propylene group or butylene group, (3) ( The preparation of the compound represented by I) is made with an alkali metal hydride and the formula (II)
[Chemical formula 5]
(Wherein, X ₁ ~X _3, and R ₁ are as defined above, Y represents. A halogen atom) according to and performing by reacting a compound represented by (2) solvent recovery reproducing method, (4) solvent recovery and recycling process according to the alkali metal sulfide hydride is characterized in that is obtained by reacting hydrogen sulfide with an alkali metal alkoxide (3), (5) ( In the production of the compound represented by I), after reacting anhydrous alkali metal sulfide with hydrogen sulfide, the formula (II)
[Chemical 6]
(Wherein, X ₁ ~X _3, R ₁ is table as defined above, Y represents a halogen atom.) According to and performing by reacting a compound represented by (2) Solvent recovery and regeneration method, ( 6 ) The base is at least one selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates, and alkaline earth metal carbonates. It is related with the solvent collection | recovery reproduction | regeneration method in any one of (1)-( 5 ) characterized.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
Specific examples of the compound having at least one hydrolyzable group to which the production method of the present invention is applied include compounds represented by the formula (I). In the compound represented by the formula (I), X _{1 to} X ₃ may be the same or different from each other, and are hydrogen or a monovalent group, at least one of which represents a hydrolyzable group.
[0008]
As the hydrolyzable group, a non-catalytic or acidic catalyst such as hydrochloric acid, sulfuric acid, nitric acid, alkoxy zirconia, alkoxy titania, or a basic catalyst such as sodium hydroxide, ammonia, tetrahydroammonium hydroxide is used. In particular, any group that can be hydrolyzed to form a silanol group or a group that can form a siloxane condensate by heating within the temperature range of room temperature (25 ° C.) to 100 ° C. Not limited. Specific examples include a hydrogen atom, an alkoxy group having 1 to 12 carbon atoms, a halogen atom, an amino group, and a carboxyl group.
[0009]
More specifically, methoxy group, ethoxy group, propoxy group, butoxy group, phenoxybenzyloxy group, methoxyethoxy group, acetoxyethoxy group, 2- (meth) acryloxyethoxy group, 3- (meth) acryloxypropoxy group 4- (meth) acryloxybutoxy group, glycidyloxy group, epoxidized cyclohexylethoxy group, methyloxetanemethoxy group, ethyloxetanemethoxy group, oxacyclohexyloxy group, fluorine, chlorine, bromine, iodine, amino group, dimethylamino group, Examples thereof include a diethylamino group, a butylamino group, a dibutylamino group, a phenylamino group, a diphenylamino group, an acetoxy group, and a ptyroyloxy group. Moreover, since hydrolyzability is especially excellent as a hydrolysable group, it is more preferable that they are a methoxy group, an ethoxy group, a propoxy group, and a butoxy group among a C1-C12 alkoxy group.
[0010]
When the functional groups X _{1 to} X ₃ include a non-hydrolyzable group, examples of the non-hydrolyzable group include a substituted or unsubstituted methyl group, ethyl group, propyl group, and phenyl group.
In the formula (I), R ₁ represents a single bond or a divalent organic group. Specifically, a substituted or unsubstituted methylene group, ethylene group, propylene group, butylene group and the like can be exemplified. Among these, a methyl group, an ethyl group, and a propyl group are more preferable because they are not bulky and do not inhibit hydrolysis of the hydrolyzable group.
[0011]
Specific examples of the compound represented by the formula (I) include compounds represented by the following formula.
[0012]
[Chemical 7]
[0013]
As the silane coupling agent, dialkoxysilane or trialkoxysilane is preferable, and trialkoxysilane is particularly preferable. The non-hydrolyzable group is preferably a methyl group or an ethyl group, particularly preferably a methyl group, from the viewpoint of reactivity and availability of raw materials.
[0014]
In the compound represented by the formula (II) used in the production of the present invention, X _{1 to} X ₃ and R ₁ have the same meaning as described above, and the same specific examples can be exemplified. Y represents a halogen atom. Specific examples of the compound represented by the formula (II) include specific examples in which a mercapto group (SH group) is substituted with a halogen atom in the specific examples of the compound represented by the formula (I). . Of the halogen atoms, a chloro atom and a bromine atom can be preferably used.
[0015]
Examples of the alkali metal hydrosulfide used in this reaction include sodium hydrosulfide and potassium hydrosulfide, and sodium hydrosulfide is preferred industrially.
Sodium hydrosulfide may be produced outside the system or produced by reacting anhydrous sodium sulfide and hydrogen sulfide in the system. Usually, hydrogen sulfide is added to the sodium alcoholate alcohol solution in the system. By injection, sodium hydrosulfide can be easily produced.
[0016]
The alkali metal hydrosulfide is preferably used in an amount of 1 mol or more per 1 mol of the compound represented by the formula (II), and more preferably in the range of 1.03 to 1.25 mol.
[0017]
The production of the compound represented by the formula (I) is preferably carried out in the presence of a solvent. Usable solvents include alcohol solvents such as methanol, ether solvents such as tetrahydrofuran, dioxane and ethylene glycol dimethyl ether, hydrocarbon solvents such as benzene, xylene, n-hexane and cyclohexane, and nitrile systems such as acetonitrile. A solvent etc. can be illustrated and these can be used individually by 1 type or in mixture of 2 or more types, However It does not specifically limit to these solvents.
[0018]
As a reaction method for obtaining the compound represented by the formula (I), an example of production of 3-mercaptopropyltrimethoxysilane will be specifically described.
In a pressure-resistant reaction vessel containing a sodium hydrosulfide solution, hydrogen sulfide, which is considered unnecessary for the original reaction, is present in the system. Specifically, 1.0~4.0kg / cm ² with hydrogen sulfide in the reaction vessel, preferably to keep the 2.0~4.0kg / cm ^2. This operation has an effect of suppressing the formation of sulfides, which has conventionally been inevitable to generate about 5 to 10%, to about 1%. In addition, since the reaction is carried out in a sealed state, hydrolysis does not occur due to moisture entering from the atmosphere, resulting in a high yield without producing a polymer.
[0019]
Next, 3-chloropropyltrialkoxysilane is gradually dropped into the reaction vessel over 1 hour, preferably 1 to 3 hours. The dropwise addition of 3-chloropropyltrialkoxysilane into sodium hydrosulfide works advantageously in suppressing the formation of a by-product sulfide. Further, when the dropping time is set to 1 hour or longer, the formation of a by-product sulfide body can be similarly suppressed. However, in 3 hours or more, it is not so improved as compared with the dripping in 3 hours.
[0020]
After completion of dropping of 3-chloropropyltrialkoxysilane, the reaction is completed at 70 ° C. or higher, preferably 90 ° C. or higher and 120 ° C. or lower. When the temperature is 70 ° C. or lower, 5 hours or more are required for the completion of the reaction. Conversely, when the temperature is 120 ° C. or higher, a large load is applied to the pressure resistance of the apparatus.
[0021]
After completion of the reaction, the target silicon compound is isolated by distillation purification.
In the solvent recovered by distillation, in addition to hydrogen sulfide added in excess, a small amount of each reaction test and target product and their decomposition products are contained.
[0022]
For example, when producing HS (CH ₂ ) ₃ Si (OMe) ₃ that is particularly useful as a silane coupling agent, Cl (CH 2) ₃ Si (OMe) ₃ or Br (CH ₂ ) is used as the starting material 3-halopropylalkoxysilane. ) ₃ Si (OMe) ₃ is used. In this case, after the completion of the reaction, in the solvent distilled off, HS (CH ₂ ) ₃ Si (OMe) ₃ , Cl (CH ₂ ) ₃ Si (OMe) ₃ or Br (CH ₂ ) ₃ Si (OMe) ₃ , (MeO) ₃ Si (CH ₂ ) ₃ SCH ₃ , (MeO) ₃ Si, which is a decomposition product of HS (CH ₂ ) ₃ Si (OMe) ₃ (CH ₂ ) ₃ S (CH ₂ ) ₃ Si (OMe) ₃ , (MeO) ₃ Si (CH ₂ ) ₃ SS (CH ₂ ) ₃ Si (OMe) ₃ , Cl (CH ₂ ) ₃ Si (OMe) ₃ or Br (CH ₂₎ a ₃ Si (OMe) impurities in ₃ (M _{O) 4 Si, (MeO)} 3 Si (CH 2) 2 CH 3 , etc. come contaminated.
[0023]
In the solvent containing hydrogen sulfide and alkoxysilanes, the base is 1 equivalent or more, preferably 2 to 4 equivalents, and water is 2 equivalents or more, preferably 10 equivalents or more with respect to hydrogen sulfide and alkoxysilanes contained in the solvent. After the addition, preferably by mixing and stirring for 30 minutes or more, hydrogen sulfide is converted to a sulfide salt, and alkoxysilanes are converted to siloxanes. Next, by distilling the solvent, a solvent free from hydrogen sulfide and alkoxysilanes can be obtained.
[0024]
As the base to be used, any of an inorganic base and an organic base can be used, and among them, an alkali metal hydroxide, an alkaline earth metal hydroxide, an alkali metal carbonate, and an alkaline earth metal carbonate are preferable. In particular, NaOH, KOH, Na ₂ CO ₃ and K ₂ CO ₃ can be preferably used.
[0025]
The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.
[0026]
【Example】
Example 1
In a 1 liter four-necked flask equipped with a stirrer, a reflux condenser, a thermometer, and a gas blowing tube, 540.2 g (2.4 mol) of a methanol solution of 24% sodium methoxide was placed, and 88.5 g of hydrogen sulfide was added from the gas blowing tube. (2.6 mol) was blown in at a temperature of 30 to 40 ° C. over 4 hours. Next, the reaction solution was placed in a 1 liter autoclave and heated until the internal temperature reached 70 ° C. The internal pressure at this time was 1.5 kg / cm ² . Here, 397.4 g (2.0 mol) of 3-chloropropyltrimethoxysilane was injected over 1 hour and reacted at 70 to 80 ° C. After injecting 3-chloropropyltrimethoxysilane, the mixture was aged for 3 hours while maintaining the temperature at 70 to 80 ° C. The reaction solution was cooled and returned to atmospheric pressure, and methanol was distilled off. The distilled methanol was 532.8 g and analyzed by gas chromatography. As a result, the contents of mixed hydrogen sulfide and alkoxysilanes were as shown below. Further, when the distilled methanol was quantified according to JIS K 0101 (1998) item 44.3 total silica 44.3.1 (melting with sodium carbonate), the Si concentration in the methanol was 2,700 ppm.
Component Content Hydrogen sulfide 1,000ppm
HS (CH ₂ ) ₃ Si (OMe) ₃ 17,400 ppm
(MeO) ₃ Si (CH ₂ ) ₃ SCH ₃ 210 ppm
(MeO) ₄ Si 1,550 ppm
(MeO) ₃ Si (CH ₂ ) ₂ CH ₃ 530 ppm
[0027]
To this methanol, 11.5 g of 49% NaOH aqueous solution and 11.5 g of water were added and stirred for 30 minutes, followed by atmospheric distillation to obtain 502.6 g of methanol. When analyzed in the same manner as before the treatment, the Si concentration was 0.5 ppm or less (below the detection lower limit), and hydrogen sulfide and alkoxysilanes were not detected.
[0028]
【The invention's effect】
As described above, by using the method of the present invention, it is possible to reuse a solvent recovered at the time of producing a silicon compound having a mercapto group and a hydrolyzable group such as 3-mercaptopropylalkoxysilane, and the production cost. It is possible to reduce the environmental load.

Claims (6)

A method for recovering and recovering a solvent, comprising producing a silicon compound containing at least one hydrolyzable group in methanol and treating the methanol recovered when purified by distillation with water and a base, followed by distillation . A silicon compound containing at least one hydrolyzable group is represented by the formula (I)
(In formula, X < ₁ > -X < ₃ > may be same or different, respectively, and is a hydrogen atom, a methyl group, an ethyl group, a propyl group, a phenyl group, a C1-C12 alkoxy group, a halogen atom, an amino group. A dimethylamino group, a diethylamino group, a butylamino group, a dibutylamino group, a phenylamino group, a diphenylamino group, an acetoxy group, a ptyroyloxy group or a carboxyl group , at least one of which represents a hydrolyzable group, and R The solvent recovery and regeneration method according to claim 1, wherein ₁ is a single bond or a compound represented by a methylene group, an ethylene group, a propylene group, or a butylene group . The production of the compound represented by the formula (I) is carried out with the alkali metal hydride and the formula (II).
(Wherein, X ₁ ~X _3, and R ₁ are as defined above, Y represents. A halogen atom) according to claim 2, characterized in that by reacting a compound represented by Solvent recovery and regeneration method. 4. The method for recovering and recovering a solvent according to claim 3 , wherein the alkali metal hydrosulfide is obtained by reacting an alkali metal alkoxide with hydrogen sulfide. The compound represented by formula (I) is produced by reacting anhydrous alkali metal sulfide with hydrogen sulfide,
(Wherein, X ₁ ~X _3, R ₁ is table as defined above, Y represents. A halogen atom) according to claim 2, characterized in that by reacting a compound represented by Solvent recovery and regeneration method. Base, 1 to claim wherein the alkali metal hydroxide, alkaline earth metal hydroxides, alkali metal carbonates, that at least one selected from the group consisting of alkaline earth metal carbonate 5 The solvent recovery and regeneration method according to any one of the above.