JPS58174390A - Preparation of n-arylaminoalkylalkoxysilane - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as a silane coupling agent, etc. in high purity and yield, by reducing the content of halogen radicals in a thermal reaction product of a specific arylamine with a halogenated alkylalkoxysilane to a specific value or below, and distilling fractionally the resultant reaction product. CONSTITUTION:(A) An arylamine expressed by formula I (A is H, alkyl, alkoxyl or vinyl; k is an integer 0-5), e.g. aniline, is reacted with (B) a halogenated alkylalkoxysilane expressed by formula II (X is Cl, Br or I; B is 1-6C alkylene; R and R<1> are 1-10C monofunctional hydrocarbon; m is an integer 1-3; lis an integer 0-2; l+m=3) under heating, and the content of halogen radicals in the reaction product is then reduced to 2,000ppm or less. The resultant reaction product is then fractionally distilled to give the aimed compound expressed by formula IV. Preferably, the reaction product is kept at -10-0 deg.C, and the deposited material is filtered off to reduce the content of the halogen radicals to 2,000ppm or less.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing N-arylaminoalkylalkoxysilane useful as a silane coupling agent with high purity and high yield.

It is known that N-arylaminoalkoxysilanes conventionally used as silane coupling agents are synthesized by the methods of formulas (1) and (2) below.

The reaction between the arylamine having an unsaturated group shown in formula (1) and hydrosilane uses an expensive platinum catalyst and the yield is not desirable.

Although the method shown in equation (2) has the advantage of not using an expensive catalyst, it has the problems of low yield, easy formation of impurities during one reaction, and difficulty in purification. Until now, there was no known improvement method.

The present inventors have conducted intensive research on a method for producing N-arylaminoalkylalkoxysilane from the conventionally known arylaminite and halogenated alkylalkoxysilane of formula (2). We discovered a method for producing N-arylaminoalkylalkoxysilane in high yield and arrived at the present invention9.Arylamines represented by 〇〇oxy groups or vinyl groups, where is an integer from 5 to 5) and ( In the formula, X is Cl*
Br or I, B is an alkylene group having 1 to 6 carbon atoms, R
and R1 is a monovalent hydrocarbon group with vertical prime numbers 1 to 10, S is an integer from 1 to 3, l is an integer from O to 2, and 9/+wm is 3. ) by fractionally distilling the heated reaction product with a halogenated alkyl alkoxysilane.

(In the formula * A + B * Rr R”* ” + '
and 閤.

In the method for producing N-arylaminoalkylalkoxysilane represented by (as described above), the N-arylaminoalkylalkoxy silane is distilled after reducing the halogen radicals in the heated reaction product to 2000 ppm or less. The present invention relates to a method for producing silane.

The content of the present invention will be explained in detail below.

The arylamine of component (a) represented by the above general formula, which is a component of the raw material of the present invention, may be any primary amine and has a hydrogen atom in the benzene ring.

Those substituted with an alkyl group, an alkoxy group or a vinyl group can be used. For example, the following can be used, but the invention is not limited thereto. Aniline,
P-toluidine, m-toluidine, 〇-toluidine, P
-Methoxyaniline, P-vinylaniline.

These include m-vinylaniline, ethylaniline, propylaniline, xylidine, trimethylaniline, and the like.

The halogenated alkyl alkoxysilane, which is the other raw material (original) component of the present invention, is represented by the above general formula,
In the formula, R and R1 are monovalent hydrocarbon groups having 1 to 10 carbon atoms, including alkyl groups such as methyl, ethyl, propyl, and octyl; alkenyl groups such as vinyl and allyl; Examples include aryl groups such as phenyl groups, arylated alkyl groups such as phenylethyl groups, and phenylprobyl groups. Preferred as R1 is an alkyl group. Further, among X representing a halogen atom, a chlorine atom is preferable. Next, examples of component (b) include γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane, 2-methyl-3-chloropropyltrimethoxysilane, 3-methyl-4-chlorobutyltriethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropylmethyljethoxysilane, γ-bromofurohil) IJ methoxysilane, β-chloroethyltrimethoxysilane, α-chloromethyl methyldimethoxysilane, a-bromobutyltrimethoxysilane, etc. It is.

The reaction product of component (a) and component (b) is
1-tolylaminoalkylalkoxysilane.

A large number of compounds can be obtained by using the fliJIiK used in components (a) and (b), but some representative examples include N-(phenyl)r-7mi/j-ropyltrimethoxysilane, N-(P-methylphenyl)γ
-aminopropyltrimethoxysilane, 2-metyl N
-(-yenyl)3-aminopropyltrimethoxysilane/IN(phenyl)γ-aminopropylmethyldimethoxysilane, N-(P-vinylphenyl)γ-aminopropyltriethoxysilane, N-(phenyl)α-ytyltriethoxysilane.

′- etc.

The reaction conditions of the present invention vary depending on the raw materials used, but can generally be carried out at a temperature of 50"0 to 200"O, preferably 100 to 1500. After the reaction is completed, the precipitated arylamine hydrogen halide compound is separated by filtration or the like, and if necessary, after distilling off the excess arylamine, the desired N-arylaminoalkylalkoxy can be obtained by distillation. can. In this reaction, the arylamine can be used at least twice the molar amount of the halogenated alkyl alkoxysilane, but is preferably between 3 and 6 times Fi.

The present inventors have discovered that when N-arylaminoalkylalkoxysilane is distilled and purified from one reaction solution and separated and recovered, if 2000 p 9 m or more of halogen groups are present in the reaction solution, the target N-arylaminoalkyl It has been found that the yield and purity of alkoxysilane are significantly impaired. The details of the form in which the halogen sFi exists in this reaction solution are unknown, but the main cause is thought to be the arylamine hydrogen halide salt produced as a by-product. In addition, free hydrogen halide may also be present in the form of a salt bound to the amine moiety of the product. Most of the arylamine hydrogen halide salts usually precipitate from the reaction solution and can be separated by filtration or other operations, but since they have some solubility in the raw materials and products, some amount can be separated. will be mixed into the reaction solution. In particular, when a large amount of arylamine is used, the amount of dissolved arylamine also increases.

The effects of skeletal halogen radicals during distillation are not always fully understood; for example,
It has been found that the cyclization reaction of N-arylaminoalkylalkoxysilane represented by formula (3) is promoted by the presence of the halogen group.

As a result of the side reaction represented by formula (3), the yield of the target product decreases and additional costs are required for purification.

We give 9 reaction yields and purity for this hydrogen halide salt concentration. As a result of examining the use of shadow sauce, it was found that if the concentration of halogen radicals in the reaction solution was 2000 ppm or less, it would not substantially have an adverse effect on the yield. In theory.

Although it is thought that the most desirable effect will be produced if the halogen radicals are reduced to zero, it is necessary to add special equipment and operations to the manufacturing process, resulting in an increase in costs. Therefore, as a simple method for reducing the free halogen radicals in the 9 reaction solution, the halogen radicals can be reduced to 2000 ppm or less by methods (A) to (C) shown below.

One or a combination of these methods can be used. Furthermore, any method other than this method that exhibits similar effects may be adopted.

(A), total amount of heating reaction products [component (a) and component (b)
2 to 5 times the total weight of the organic solvent is added to precipitate by-products such as arylamine hydrogen halide salts, which are removed by filtration or the like. Hexane and toluene are used as organic solvents.

Ether etc. are used. The organic solvent may be added after the reaction is completed, or may be added after the by-products that precipitate are removed by cooling after the completion of one reaction.
It may be added after the excess raw material has been distilled off. In short, after the completion of one reaction and before the purification distillation, the heated reaction product (B) is cooled to precipitate the by-product of the arylamine hydrogen halide salt.

Remove with filter fathom. The cooling temperature is preferably -10"0 to O"0.

(C) A basic compound is added to the heated reaction product to generate stable neutral salts as by-products, which are then removed by filtration or the like.

Sodium carbonate, sodium methylate, triethylamine, etc. are used.

Incidentally, the timing of addition of the basic compound is not particularly limited, as is the case with the addition of the organic solvent, and it may be added between the end of the 9th reaction and the time of purification distillation.

The N-arylaminoalkylalkoxysilanes produced according to the present invention are useful as silane coupling agents, such as glass fiber treatment agents for laminates, rubber or resin filler treatment agents, rubber or resin additives, It has many uses, such as a surface modifier for resins, an additive for paints, a primer, and various adhesive properties. In the examples, the term "weight f%" means "weight f%".

Example 1 Aniline 70% was added to a reaction vessel made of 2001 glass lining.
3 kf (756 mol) was charged and stirred.

The mixture was heated with steam to 130 to 140°C to reach the liquid temperature. r-chloropropyltrimethoxysilane 300 YU (1
51 mol) was gradually added dropwise over 2 hours so that the liquid temperature could be maintained at 130 to 140°C.
The reaction was carried out at ~140°C for 3 hours. After cooling, the aniline hydrochloride precipitated in the reaction solution was removed, and the resulting solution was subjected to a reduced pressure of 50 W Hg and a solution temperature of 100°C to remove excess raw materials to obtain a distilled crude solution of 346 kf. . This crude liquid is soo as a chlorine radical.

# was added to 50 ppm of o-toluene.

After cooling to 5° () and leaving overnight, the precipitated salt was filtered, and toluene was distilled off under reduced pressure [50 μHg and liquid temperature of 100°C. When the chlorine radical was measured again, it was found that 14
It had decreased to 0.00 ppm. This concentrated liquid before purification was subjected to vacuum simple distillation, with a boiling point of 123 to 141°C [vacuum pressure WL 2wmHg
) was obtained as a slightly yellow transparent liquid with a fraction of 28.9 yu. Analysis by gas chromatography showed that this fraction had the target substance N-(7enyl)r-aminopropyltrimethoxysilane with a purity of 9'L4H and a refractive index (25°C
) 1.5049° Chlorine content was 800 ppm. 7 for the starting material γ-chloropropyltrimethoxysilane
The yield was 5.

Example 2 The raw materials, amounts used, and reaction conditions used in Example 1 were the same, and the resulting distilled crude liquid was treated in various ways to prepare concentrated liquids before purification with different chlorine radical contents. Table 1 shows the results of investigating the relationship between this chlorine radical concentration and the purity and yield of the target product after distillation purification.

Table 1 It can be seen from the above table that when the salt content in the concentrated solution before purification exceeds 2000 ppm, both the yield and purity of the target γ-anilinopropyltrimethoxysilane decrease significantly.

Example 3 Distilled crude liquid 342 k# (contains salt purple root 7
800ppm), 25% of thorium methoxide
Thimethanol solution was added until the distilled crude solution became neutral. - After standing overnight, the sodium chloride formed was filtered.

The chlorine content in the filtrate was 5 ppm. The added liquid was subjected to simple vacuum distillation. A fraction with a boiling point of 123 to 141"O (degree of vacuum: 2 mHg) was collected and analyzed by gas chromatography.

It contained 99.1% of the target N-(phenyl)r-aminopropyltrimethoxysilane, and its chlorine radical was below the detection limit.

Example 4 Aniline 465 in 21 three-necked flasks! i/ (
6 mol) was charged and blown. The liquid temperature was heated to 150° C. without stirring, 212.5 g (1 mol) of 2-methyl-3-chloropropyltrimethoxysilane was added dropwise, and the temperature was maintained at this temperature for 10 hours after completion of stirring. After the reaction was completed, the mixture was cooled and the precipitated aniline salt was filtered. The chlorine content in the furnace fluid was 12,000 ppm. IJum was added in an amount of 5% of the total weight of the furnace liquid, stirred for 5 hours, and then filtered through a glass filter. The content of salt purple roots in this furnace liquid was reduced to 150 ppm. The furnace liquor was first distilled to remove excess aniline at 100 °C under a vacuum of 60 + wHg, followed by boiling at 130 °C under a vacuum of 1 mg.
229g of a slightly yellow fraction at ~135°C was collected. The yield was 8S- based on the 2-methyl-3-chloropropyltrimethoxysilane used, and the purity was 97.5% by gas chromatography analysis. In addition, it was confirmed by FiNMH of the fraction that it was 2-methyl-N-(phenyl)3-aminopropyltrimethoxysilane.

Claims (1)

[Scope of Claims] An arylamine represented by (wherein A is a hydrogen atom, an alkyl group, an alkoxy group, or a vinyl group, and an integer from 1 to 5). (In the formula, X is C1, Br or I, B has 1 to 6 carbon atoms
alkylene group, R and R1 are 1 having 1 to 10 carbon atoms;
fItJJ hydrocarbon group, S is an integer from 1 to 3, l is an integer from O to 2, but! +m ij 3. ) by fractional distillation of the heated reaction product with a halogenated alkyl alkoxysilane. In the method for producing N-arylaminoalkylalkoxysilane represented by the formula e At Be R, R', &, z and crane are as described above, the /S rogen group in the heated reaction product is A method for producing N-arylaminoalkylalkoxysilane, which comprises distilling after reducing the concentration to 2000 ppm or less. 2. Add 0.2 to 5 times the amount (weight) of an organic solvent to the total amount of the heated reaction product and separate the precipitate in the furnace.
The manufacturing method according to claim 191, wherein the halogen content is reduced to 2000 pPm or less. 3. After heating the reaction product and keeping it at -10℃-0℃. By separating the precipitates, 2000p of halogen roots can be removed.
pm or less, the manufacturing method according to claim 1. Table By adding an inorganic base or an organic base to the heated reaction product and separating the precipitate in a furnace. Halogen roots below 2000ppm! A manufacturing method according to claim 1.