JP3068113B2 - Acrylic silane distillation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION In the production of chlorosilane or acetoxysilane (hereinafter referred to as "acrylsilane") having a methacryloxy group or an acryloxy group on an industrial scale, spontaneous polymerization of acrylsilane generated in a distillation step is suppressed. To a distillation method.

[0002]

BACKGROUND ART Acrylic silane is a silane coupling agent, a raw material of a silane coupling agent, a raw material of a polysiloxane, a terminating agent in the production of polysiloxane, a surface treatment agent for various base materials, a modified material of various resins, and the like. Effective for a wide range of applications. Such highly useful acrylic silane was obtained after performing a hydrosilylation reaction between an acrylate or methacrylate having an unsaturated site and a hydrosilane compound in the presence of a transition metal catalyst such as platinum. The reaction solution is generally produced by a method of purifying by distillation under reduced pressure.

[0003] Such a production example is disclosed in Japanese Patent Publication No. 6-51707.
JP-A-2003-157, which discloses a method for producing 3-methacryloxypropyldimethylchlorosilane by reacting allyl methacrylate and methyldichlorosilane in the presence of a platinum catalyst, and then performing distillation under reduced pressure. .

[0004] However, acrylic silane can be a raw material for producing various functional materials due to its high polymerizability. On the other hand, in the synthetic reaction process, purification process, storage process and transportation process of acrylic silane, It has a disadvantage that it is easily spontaneously polymerized thermally. For this reason, when heating at room temperature or higher is required in the synthesis reaction process of acrylic silane, or when heating at room temperature or higher in the distillation purification step after the synthesis reaction, how to prevent spontaneous polymerization of acrylic silane Is the most important. As a method of preventing spontaneous polymerization, it is a general method to add a polymerization inhibitor in a synthesis reaction step or a distillation purification step,
Usually, phenolic polymerization inhibitors such as hydroquinone and methoquinone are used.

[0005] However, the phenol polymerization inhibitor causes a condensation reaction with acrylic silane (hereinafter, referred to as chlorosilane) in which a chlorine atom is bonded to a silicon atom,
It has the disadvantage that the ability to inhibit polymerization is lost. This is described in Japanese Patent Publication No. Hei 6-51707 and a paper by Efimov et al. (Zh. Obsch. Khim. (1991) 61 (10) 2244).
-53).

In general, the performance of the polymerization inhibitor is determined by using a methacrylic acid ester or an acrylic acid ester and heating the ester to a temperature at which the ester spontaneously polymerizes. The judgment is made by a method for examining how much spontaneous polymerization is suppressed. Usually, such tests are performed by beaker scale table tests. A number of polymerization inhibitors have been studied based on this method.

[0007] Above all, hindered phenols represented by 2,6-di-t-butyl-4-methylphenol and amines represented by N, N'-diphenyl-p-phenylenediamine or phenothiazine are: It was found to be extremely effective as a polymerization inhibitor for acrylic silane. However, when the scale is increased to an industrial scale, spontaneous polymerization of acrylic silane cannot be sufficiently suppressed only by adding the hindered phenols and the amines.

[0008]

The inventors of the present invention have conducted intensive studies on the above problems, and as a result, have found that there are two types of spontaneous polymerization of acrylsilane, namely, homogeneous polymerization and multiplication polymerization. . Homogeneous polymerization is a process in which the viscosity of a solution gradually increases with the polymerization of acrylic silane and solidifies in a purine-like manner.On the other hand, proliferation polymerization is an abnormal reaction in free radical polymerization and forms a popcorn-like shape in a solution. Insoluble polymer is produced, which gradually grows,
It has a form that expands. When the acrylic silane undergoes multiplication, the volume of the polymer becomes twice or more that of the monomer, which not only causes blockage of the reactor and piping, but also causes a serious accident such as destruction of the device.

Although the reason is not clear, in the table test, the dependence of uniform polymerization is extremely high, and propagation polymerization is hardly observed. As described above, even if the performance of the polymerization inhibitor is examined in the table test, it is only possible to grasp the effect on the uniform polymerization, and even if the scale-up is performed based on the result, the proliferation polymerization is suppressed. You can't. Therefore, when scaling up to an industrial scale, it is necessary to establish a polymerization inhibitor capable of preventing both homogeneous polymerization and propagation polymerization, and a production method using the inhibitor.

An object of the present invention is to suppress the uniform polymerization and the propagation polymerization simultaneously in the production of acrylic silane on an industrial scale, particularly in the purification step by distillation under reduced pressure, and to greatly reduce the spontaneous polymerization of acrylic silane. It is an object of the present invention to provide a distillation method which can be prevented.

[0011]

The present invention has the following constitutions (1) and ( 2 ). (1) N, N'-diphenyl-p-phenylenediamine is purified by distillation of acrylsilane represented by the general formula (I).
Alternatively, a method for distilling acrylsilane in the presence of an amine compound, which is phenothiazine, and an N-nitrosophenylhydroxylamine salt. CH ₂ ＣＲCR ¹ COO (X) _m SiR ² _n R ³ _3-n (I) wherein R ¹ is hydrogen, an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 10 carbon atoms And X is CH ₂ C
H ₂ O or CH ₂ or a combination of these two groups, m is 1 to 12, R ² is a hydrolyzable group, R ³ is an alkyl group having 1 to 12 carbon atoms, alkenyl A group or an aryl group, and n is 1 to 3. (2) N-nitrosophenylhydroxylamine salt is
Formula (II) (R ⁴ N (NO) O) _p Y _q (II) wherein R ⁴ is an aryl group having 6 to 10 carbon atoms;
p is 1-4, q is 1-4, and Y is a cation atom or molecule. The method for distilling acrylsilane according to the above (1), which is a compound represented by the following formula (1):

Hereinafter, the present invention will be described in detail. The present invention relates to the production of acrylic silane on an industrial scale ,
N'-diphenyl-p-phenylenediamine or
Amine compounds that are nothiazines (in the following description
"Amine compound" means
"N, N'-diphenyl-p-phenylenediamine or
Means an amine compound which is a phenothiazine. )
And an N-nitrosophenylhydroxylamine salt in the presence of an acrylic silane.

The N-nitrosophenylhydroxylamine salt used in the present invention is not effective in preventing spontaneous polymerization of acrylsilane when its polymerization inhibitory effect is examined by a table test. Therefore, it is preferably used as a polymerization inhibitor. However, when used in the present invention, they exhibit extremely excellent polymerization inhibiting ability. Such an N-nitrosophenylhydroxylamine salt is represented by the following general formula (II). (R ⁴ N (NO) O) _p Y _q (II) wherein R ⁴ is an aryl group having 6 to 10 carbon atoms;
p is 1-4, q is 1-4, and Y is a cation atom or molecule. Specific examples thereof include N-nitrosophenylhydroxylamine ammonium salt, N-nitrosophenylhydroxylamine sodium salt, N-nitrosophenylhydroxylamine potassium salt, and N-nitrosophenylhydroxylamine aluminum salt.

The amount of the N-nitrosophenylhydroxylamine salt used in the present invention is preferably 1 to 100,000 ppm (in terms of weight) based on acrylic silane.
10 to 5000 ppm (weight conversion) is more preferable. The N-nitrosophenylhydroxylamine salt used in the present invention can be prepared by using the compound of the above general formula (II) alone.
A plurality of them may be used in combination. Specific methods of use include, for example, a method of adding immediately before an acrylic silane synthesis reaction step, a method of previously mixing the raw material of the acrylic silane, and a method of adding into a reaction mixture immediately before a distillation purification step. can do. However, the N-nitrosophenylhydroxylamine salt has an excellent effect in suppressing the growth polymerization, but has no effect in suppressing the uniform polymerization, and therefore must be used in combination with the amine compound .

Specific examples of the amine compound used in the present invention include N, N'-diphenyl-p-phenylenediamine, phenothiazine, and the like.

The amount of the amine compound used in the present invention is from 1 to 100,000 ppm based on acrylic silane.
(Weight conversion) is preferable, and 10 to 1000 ppm (weight conversion) is more preferable.

Specific examples of the method of use include a method of adding the acrylic silane immediately before the synthesis reaction step, a method of previously mixing the raw material of the acrylic silane, and a method of adding the reaction mixture immediately before the distillation purification step. And the like. However, the amine compound has an excellent effect in suppressing the uniform polymerization, but has no effect in suppressing the growth polymerization. Therefore, the amine compound must be used in combination with the N-nitrosophenylhydroxylamine salt.

In the present invention, the acrylic silane capable of effectively suppressing polymerization is represented by the general formula (I). CH ₂ = CR in ^{_{1 COO (X) m SiR 2}} n R 3 3 _over n ... (I) [wherein, R ¹ is hydrogen, aryl alkyl group or the carbon number of 1 to 8 carbon atoms is 6 to 10 And X is CH ₂ C
H ₂ O or CH ₂ or a combination of these two groups, m is 1 to 12, R ² is a hydrolyzable group, R ³ is an alkyl group having 1 to 12 carbon atoms, alkenyl A group or an aryl group, and n is 1 to 3. ]

Among them, R ² is —OC (＝ O) R ⁵ [wherein R ⁵ is an alkyl group having 1 to 8 carbon atoms and 1 to 8 carbon atoms.
An alkenyl group having 8 carbon atoms, an alkynyl group having 1 to 8 carbon atoms, or an aryl group having 6 to 10 carbon atoms. ], ^{Preferably, -OC (= O) CR 6} = CH 2 [ wherein, R ⁶ is an alkyl group or hydrogen to 2 carbon atoms. Or a halogen element, particularly preferably —OC (＝ O) CH ₃ or a chlorine atom.

Specifically, 3-methacryloxypropyltrichlorosilane, 3-methacryloxypropylmethyldichlorosilane, 3-methacryloxypropyldimethylchlorosilane, 3-acryloxypropyltrichlorosilane, 3-acryloxypropylmethyldichlorosilane, 3-acryloxypropyldimethylchlorosilane,
Examples thereof include 3-methacryloxypropyldimethylacetoxysilane, 3-methacryloxypropyldimethylmethacryloxysilane, 3-acryloxypropyldimethylacetoxysilane, and 3-acryloxypropyldimethylacryloxysilane.

In the production method of the present invention, a gas or air obtained by diluting molecular oxygen with an inert gas may be introduced.

[0022]

The present invention will be described below in detail with reference to Examples, Comparative Examples and Reference Examples. Note that the present embodiment does not limit the present invention at all.

Example 1 A reaction mixture containing 3-methacryloxypropyldimethylchlorosilane as a main component was synthesized from allyl methacrylate and dimethylchlorosilane in the presence of a platinum catalyst by a known method. 6.5 g of N-nitrosophenylhydroxylamine aluminum salt and 65.7 g of phenothiazine were added to 6.28 kg of the reaction mixture.
Was dissolved and purified by distillation using a simple distillation apparatus having no distillation column. After distilling off low boiling components mainly composed of allyl methacrylate at 40 kPa and an overhead temperature of 30 to 50 ° C., 15 k
A fraction of 3-methacryloxypropyldimethylchlorosilane having a top temperature of 85 to 90 ° C. under Pa was obtained. During this distillation purification, no polymerization in which the viscosity of the still was increased was observed, and no production of a multiplying polymer was observed.

Example 2 2,6-di-tert-butyl-4
Example 1 except that 0.66 g of -methylphenol was added.
The same distillation purification operation as that described above was performed. During this distillation purification, no polymerization in which the viscosity of the still was increased was observed, and no production of a multiplying polymer was observed.

(Example 3) Instead of phenothiazine,
The same distillation and purification operation as in Example 1 was performed except that 0.66 g of 2,6-di-tert-butyl-4-dimethylaminomethylphenol was added. During this distillation purification, no polymerization in which the viscosity of the still was increased was observed, and no production of a multiplying polymer was observed.

(Comparative Example 1) The same distillation purification operation as in Example 1 was performed except that 68 g of phenothiazine was added instead of adding phenothiazine and aluminum N-nitrosophenylhydroxylamine. After distilling off low-boiling components mainly composed of allyl methacrylate at 40 kPa and an overhead temperature of 30 to 50 ° C., a growth polymer was formed in the still and gradually grew, and the distillation purification operation became impossible.

(Comparative Example 2) Instead of adding phenothiazine and aluminum N-nitrosophenylhydroxylamine, 0.66 g of phenothiazine and 2,6-di-t
-Butyl-4-dimethylaminomethylphenol 0.6
Except for adding 6 g, the same distillation purification operation as in Example 1 was performed. In the course of distilling off low-boiling components mainly composed of allyl methacrylate at 50 kPa and an overhead temperature of 30 to 40 ° C., a distillation polymerizing operation was stopped because a growing polymer was formed in the distillation still.

(Comparative Example 3) The same distillation and purification operation as in Example 1 was carried out except that 0.75 g of phenothiazine and 0.75 g of anhydrous cupric chloride were added instead of adding phenothiazine and aluminum N-nitrosophenylhydroxylamine. Done. After distilling off low-boiling components mainly composed of allyl methacrylate at 40 kPa and an overhead temperature of 30 to 50 ° C., a growth polymer was formed in the still and gradually grew, and the distillation purification operation became impossible.

REFERENCE EXAMPLE A reaction mixture containing 3-methacryloxypropyldimethylchlorosilane as a main component was synthesized from allyl methacrylate and dimethylchlorosilane in the presence of a platinum catalyst by a known method. This reaction mixture 50
In 6 g, 5.1 g of phenothiazine was dissolved and purified by distillation. After distilling off low-boiling components mainly composed of allyl methacrylate at 40 kPa and an overhead temperature of 30 to 60 ° C., 15 k
A fraction of 3-methacryloxypropyldimethylchlorosilane having a top temperature of 65 to 75 ° C. under Pa was obtained. During this distillation purification, no polymerization in which the viscosity of the still was increased was observed, and no production of a multiplying polymer was observed.

[0030]

As is clear from the examples and comparative examples, when a hindered phenol compound and / or an amine compound is used in combination with an N-nitrosophenylhydroxylamine salt, acrylic silane is produced on an industrial scale. At this time, it is understood that the spontaneous polymerization of acrylsilane generated in the distillation purification step can be suppressed. Although it is difficult to clearly explain the reason, the hindered phenol compound, the amine compound, and the N-nitrosophenylhydroxylamine salt do not volatilize and decompose under the distillation and purification conditions of acrylsilane, and always remain in the still. Hindered phenol compound, amine compound, N-nitrosophenylhydroxylamine salt
It is presumed that the reason is that they do not react with chlorosilane, unlike phenols such as hydroquinone, which is usually used as a polymerization inhibitor for acrylic silane. In addition, as is apparent from the reference example, in the beaker test, no growth polymerization occurs, but when this is scaled up to the level of Comparative Example 1, the growth polymerization occurs. Therefore, although it is very dangerous to scale up to an industrial scale based on the results of the conventional test method, the beaker test, the distillation method of the present invention requires study on the level of an actual industrial scale. Therefore, even if industrial production is performed based on this result, it can be performed without any problem. Further, N-nitrosophenylhydroxylamine salt has a poor polymerization inhibitory effect in a beaker test and has not been favorably used as a conventional polymerization inhibitor. Was found to have a very high polymerization inhibitory effect when used on an industrial scale.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C07F 7/18 CA (STN) REGISTRY (STN)

Claims (2)

(57) [Claims] 1. A method for purifying an acrylic silane represented by the general formula (I) by distillation using N, N′-diphenyl-p-phenylene.
An amine compound that is a diamine or phenothiazine ;
A method for distilling acrylic silane, wherein the method is carried out in the presence of N-nitrosophenylhydroxylamine salt. CH ₂ ＣＲCR ¹ COO (X) _m SiR ² _n R ³ _3-n (I) wherein R ¹ is hydrogen, an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 10 carbon atoms And X is CH ₂ C
H ₂ O or CH ₂ or a combination of these two groups, m is 1 to 12, R ² is a hydrolyzable group, R ³ is an alkyl group having 1 to 12 carbon atoms, alkenyl A group or an aryl group, and n is 1 to 3. ] 2. An N-nitrosophenylhydroxylamine salt represented by the general formula (II) (R ⁴ N (NO) O) _p Y _q ... (II) wherein R ⁴ is an aryl having 6 to 10 carbon atoms. Group,
p is 1-4, q is 1-4, and Y is a cation atom or molecule. The method for distilling acrylsilane according to claim 1, wherein the compound is represented by the following formula: