JP2644160B2 - Method for producing isocyanate group-containing organopolysiloxane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for producing an isocyanate-containing organopolysiloxane, and more particularly to an isocyanate group capable of producing an isocyanate-containing organopolysiloxane in a high yield by reacting an amino-containing organopolysiloxane with phosgene. The present invention relates to a method for producing a contained organopolysiloxane.

[0002]

BACKGROUND OF THE INVENTION Organic functional groups in which isocyanate groups have an active hydrogen, such as hydroxyl, carbamate, primary and secondary groups.
It is well known that it reacts with a class of amino group, carboxyl group, etc. to form a urethane bond or a urea bond.
These reactions are industrially useful. Therefore, an organopolysiloxane containing one isocyanate group in a molecule can be used to convert an organic compound containing active hydrogen into a silicone-based compound.
It is very useful when denatured.

A method for synthesizing this isocyanate group-containing compound by reacting phosgene with a corresponding primary amino group-containing siloxane has been industrialized, and the formula H ₂ N (CH ₂ ) _3- By reacting phosgene on Si [OSi (CH ₃ ) ₃ ] ₃ in an organic solvent, the formula NCO (CH ₂ ) ₃ Si [O-Si
A method for obtaining an isocyanate group-containing organopolysiloxane represented by (CH ₃ ) ₃ ] ₃ is known (US Pat. No. 3,584,
No. 024).

[0004]

However, in this method, since a large amount of hydrochloric acid is by-produced, 10 to 30% of the siloxane bond is cleaved by the hydrochloric acid, and the yield of the desired isocyanate group-containing organopolysiloxane is reduced. Decreased, and satisfactory results could not be obtained.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a method for producing an isocyanate group-containing organopolysiloxane which has solved the above-mentioned drawbacks, and comprises one compound per molecule represented by the following general formula (Formula 4). Phosgene is allowed to act on an organopolysiloxane containing an amino group of formula (I), and a chlorosiloxane by-produced by cleavage of the obtained siloxane is reacted with a silanol compound represented by the following general formula (Chemical Formula 5). It is characterized in that an organopolysiloxane containing one isocyanate group in a molecule represented by the chemical formula 6) is produced.

Embedded image [Wherein R ¹ is an unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms or a group in which part or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with a halogen atom or a cyano group] , R ² , R ³ , R ⁴ are the same as R ¹ or of the formula -OSiR ⁵ R ⁶ R
A siloxy group represented by ⁷ (R ⁵ , R ⁶ and R ⁷ are the same as R ¹ ), n
Is an integer of 1 to 10, and a is 0, 1 or 2. ]

Embedded image

Embedded image (Where R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , n, a are the same as above)

The present inventors have made various studies to develop a method for obtaining an isocyanate group-containing organopolysiloxane at a high yield. A method for producing an isocyanate group-containing organopolysiloxane by reacting phosgene with an amino group-containing organopolysiloxane is known. Is reduced. The inventors of the present invention have found that when a silanol compound is reacted with chlorosiloxane generated by cleavage of siloxane, isocyanate group-containing organopolysiloxane is generated from this, and that the yield of isocyanate group-containing organopolysiloxane is improved. Was completed. This will be described in more detail below.

The amino group-containing organopolysiloxane used in the present invention is represented by the general formula (Chemical Formula 1) having one primary amino group in the molecule. In the formula
Examples of R ¹ include an alkyl group such as a methyl group, an ethyl group, a propyl group and a butyl group, a cycloalkyl group such as a cyclopentyl group and a cyclohexyl group, an aryl group such as a phenyl group, an aralkyl group such as a benzyl group, a vinyl group, and an allyl group. An alkenyl group such as a group, or a part or all of the hydrogen atoms bonded to carbon atoms of these groups are substituted with a halogen atom, a cyano group, for example, a chloromethyl group,
3,3-trifluoropropyl group, a monovalent hydrocarbon radical unsubstituted or halogen atoms or 1 to 8 carbon atoms cyano group substitution selected from such cyanoethyl, R ^2,
R ³ and R ⁴ are the same monovalent hydrocarbon group having 1 to 8 carbon atoms as R ¹ or a siloxy group represented by the formula —OSiR ⁵ R ⁶ R ⁷
R ⁵ , R ⁶ and R ⁷ are exactly the same as R ¹ . Examples of the siloxy group include a trimethylsiloxy group, an ethyldimethylsiloxy group, a phenyldimethylsiloxy group, a vinyldimethylsiloxy group, a chloromethyldimethylsiloxy group,
And a 3-trifluoropropyldimethylsiloxy group. R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , and R ⁷ may be the same or different, but each is preferably a methyl group.

The amino group-containing organopolysiloxane can be obtained, for example, by subjecting a primary amino group-containing alkoxysilane and a silanol to a transesterification reaction represented by the following general formula (Formula 7). As R ^{8 in} this formula, a methyl group, an ethyl group, a propyl group, a butyl group, an isopropenyl group, an acetyl group, etc. are exemplified, and a methyl group is preferable in consideration of the transesterification rate and the availability of raw materials. .

Embedded image

In the present invention, the amino group-containing organopolysiloxane is reacted with phosgene, and the molar ratio between the former and phosgene must be equal to or more than one. However, in order to carry out an efficient and complete reaction, the amino group-containing organopolysiloxane is required to be 3 to 3 times.
It is good to make it 5 times mol. The reaction between the amino group-containing organopolysiloxane and phosgene is carried out in the following two-step reaction formula.

Embedded image

Embedded image (Wherein R is an alkylene group), the products of the first reaction represented by this formula are carbamate chloride and amine hydrochloride, the intermediates of which are secondary
To obtain the desired isocyanate group-containing organopolysiloxane.

The reaction temperature in the first reaction is -20 to 2
The temperature is preferably set to a relatively low temperature of 5 ° C, and the reaction temperature in the second reaction is advantageously set to a high temperature.
However, in order to suppress the siloxane cleavage reaction, the temperature is preferably set to 50 to 100 ° C. This reaction may be carried out in the presence of an organic solvent, and the organic solvent used here may be inactive in the reaction system. Linear, branched or cyclic aliphatic hydrocarbons such as n-pentane, n-hexane, isooctane, cyclohexane, cyclooctane, aromatic hydrocarbons such as benzene, toluene, xylene, methylene chloride, chloroform, carbon tetrachloride Examples thereof include ethers such as halogenated hydrocarbons, diethyl ether, dibutyl ether, tetrahydrofuran, and dioxane. When the amino group-containing organopolysiloxane to be reacted has a low viscosity, the reaction may be carried out without a solvent.

The second reaction is carried out at a temperature of 50 to 100 ° C. in order to suppress the siloxane cleavage reaction as described above. However, even if the reaction is carried out under these conditions, hydrochloric acid is by-produced. The siloxane bond is cleaved by hydrochloric acid to produce a chloro group-containing organopolysiloxane represented by the general formula (Formula 10).

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In the present invention, in order to convert this chloro group-containing organopolysiloxane to an isocyanate group-containing organopolysiloxane, the former is reacted with a silanol compound represented by the following chemical formula (2).

This reaction involves a tertiary amine such as triethylamine, tri-n-butylamine, N, N, N ', N'.
Aliphatic amines such as tetramethyl-1,3-butanediamine; aromatic amines such as N, N-dimethylaniline and N, N-diethylaniline; heterocyclic tertiary amines such as pyridine and picoline; N-ethyl Morpholine, 1,4
It is preferred to carry out the reaction in the presence of a cyclic tertiary amine such as -diazabicyclo (2,2,2) octane, 1,8-diazabicyclo (5,4,0) undecene-7.

This reaction may be carried out at a temperature of -30 to 200 ° C., preferably at 20 to 80 ° C.
Three hours may be used. After completion of the reaction, the tertiary amine hydrochloride is removed by filtration or the reaction solution is removed by washing with water, and the desired isocyanate group-containing organopolysiloxane is obtained in a yield of 78% or more by distilling the reaction solution. be able to.

[0015]

The following are examples of the present invention and comparative examples, but the present invention is not limited to these examples. (Example 1) The inside of a flask equipped with a gas inlet tube, a dropping funnel, a cooling tube, a thermometer, and a stirring device was purged with nitrogen, and toluene 10 was added thereto.
0 g and cooled to -10 ° C.
(0.3 mol) of phosgene was blown in.

Next, the following formula is added to this flask.

Embedded image 27 g of an amino group-containing organopolysiloxane represented by the formula:
(0.075 mol) was added dropwise, the internal temperature was increased from 20 ° C. to 30 ° C. during the dropping, and the mixture was stirred at 30 ° C. for 30 minutes and then heated. However, when the mixture was heated for 3 hours, the reflux temperature rose to 85 ° C.
Distilled until it became. Next, the formed trimethylchlorosilane was removed.

Next, the reaction solution was cooled to room temperature, and 7.5 g (0.075 mol) of triethylamine and 6.8 g (0.075 mol) of trimethylsilanol were added dropwise. After the addition, the reaction solution was heated. The reaction was carried out at 50 ° C. for 1 hour, and the formed triethylamine hydrochloride was filtered off and purified by distillation. OCN (CH ₂ ) ₃ Si [OSi (CH ₃ ) ₃ ] _{3 having} a boiling point of 90 ° C./2 mmHg
23 g was obtained (80% yield).

Example 2 A reaction was carried out in the same manner as in Example 1 except that 5.9 g (0.075 mol) of pyridine was used as a tertiary amine in place of triethylamine in Example 1. After reacting at 50 ° C. for 1 hour, the reaction solution was washed with 50 g of water for the purpose of removing the generated pyridine hydrochloride, and after washing with water, toluene was distilled off from the toluene layer and purified.
25 g of (CH ₂ ) ₃ Si [OSi (CH ₃ ) ₃ ] ₃ were obtained (88% yield).

[0019] (Example 3) H ₂ N used in Example _{1 (CH 2) 3 Si [} OSi (CH 3) 3] 3 2
7 g (0.075 mol) of the following formula

Embedded image 21 g of an amino group-containing organopolysiloxane represented by the formula:
(0.075 mol), except that it was treated in the same manner as in Example 1.

Embedded image 18 g (yield: 78%) of an isocyanate group-containing organopolysiloxane (boiling point: 84 ° C./2 mmHg) represented by the formula:

Comparative Example 1 The reaction liquid was purified by distillation without adding triethylamine and trimethylsilanol in Example 1, and OCN (CH ₂ ) ₃ Si (Cl) [OSi (CH ₃ ) ₃ ] After cutting ₂ and rectifying it, the target OCN (CH ₂ ) ₃ Si [OSi (CH
₃ ) ₃ ] ₃ 11 g (yield 39%) was obtained.

[0021]

According to the present invention, an isocyanate group-containing organopolysiloxane useful for silicone-modifying various organic compounds can be obtained in high yield.

Claims (1)

(57) [Claims] 1. A compound of the general formula [Wherein R ¹ is an unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms or a group in which part or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with a halogen atom or a cyano group] , R ² , R ³ , R ⁴ are the same as R ¹ or of the formula -OSiR ⁵ R ⁶ R
A siloxy group represented by ⁷ (R ⁵ , R ⁶ and R ⁷ are the same as R ¹ ), n
Is an integer of 1 to 10, and a is 0, 1 or 2. Phosgene acts on an organopolysiloxane containing one amino group in the molecule represented by the following formula, and the resulting chlorosiloxane produced by cleavage of the siloxane is converted into a silanol represented by the following general formula (Chemical Formula 2). A method for producing an isocyanate group-containing organopolysiloxane, which comprises reacting a compound to produce an organopolysiloxane having one isocyanate group in a molecule represented by the following general formula (Formula 3). Embedded image Embedded image (Where R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , n, a are the same as above)