JPH07309884A - Production of trialkylphenyl phosphite - Google Patents

Abstract

PURPOSE:To obtain a trialkylphenyl phosphite, useful for an antioxidant used in a molding processing of thermoplastic resins, in high yield and purity by reacting phosphorus trihalide with a dialkylphenol in the presence of a specific catalyst. CONSTITUTION:This method for producing a trialkylphenyl phosphite is to react phosphorus trihalide with a mono- and a dialkylphenol using an oxide of a bivalent group IIA metal of the Periodic Table (magnesium oxide, calcium oxide, etc.). The reaction proceeds under mild t conditions in a relatively short time. The catalyst can be removed by simple filtration without using a neutralization process and hardly remains in the product.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing trisalkylphenylphosphite, and more particularly to a method for producing trisalkylphenylphosphite by reacting phosphorus trihalide with mono- and dialkylphenols in the presence of a catalyst. It is a thing.

Trisalkylphenyl phosphite is A
It is widely used together with phenolic antioxidants as antioxidants during molding of thermoplastic resins such as BS resins and polyolefins.

[0003]

As a method for producing trisalkylphenyl phosphite, (1) a method for producing phosphorus trihalide and mono- or dialkylphenol in the absence of a catalyst, (2)
A method in which a metal, a metal halide or a Lewis acid is present as a catalyst, (3) a method using a nitrogen-containing aromatic heterocyclic compound as a catalyst (Soviet Patent No. 488821), (4)
Method using a catalyst such as amine or phosphine (Japanese Patent Laid-Open No. 54-3
No. 0140 specification) and the like are known.

[0004]

However, these known methods have some drawbacks as described below, and are not yet satisfactory methods.

That is, in the method (1), in order to obtain a high reaction rate, it is necessary to heat and react at a high temperature for a long time, and as a result, the byproduct of impurities lowers the product purity and also the selectivity. descend.

In the method (2), some metal halides and Lewis acids have an effect of promoting the reaction, but still require a high temperature reaction. Further, in the case of producing liquid trisalkylphenyl phosphite, when a strong base is used for catalyst neutralization, the formed trisalkylphenyl phosphite is decomposed, while when a weak base is used, the catalyst is sufficiently removed. Not done to.

In the methods (3) and (4), a large amount of catalyst is required to obtain a sufficient reaction rate, and as a result, the selectivity of phosphorus trihalide is deteriorated, resulting in a decrease in product purity and a decrease in yield. Cause

Therefore, the above-mentioned known method is not always sufficient as a method for producing a trisalkylphenylphosphite which is efficient, has a high yield, and is easy to remove the catalyst.

[0009]

DISCLOSURE OF THE INVENTION As a result of various studies to solve these problems, the present invention has revealed that when trisalkylphenyl phosphite is produced by reacting phosphorus trihalide with mono- and dialkylphenols. Periodic table 2A
The inventors of the present invention have found that oxides of group III metals have excellent catalytic effects and have reached the present invention.

That is, the present invention is a method for producing trisalkylphenylphosphite by reacting phosphorus trihalide with mono- and dialkylphenols in the presence of a catalyst, and a metal oxide of Group 2A of the periodic table is used as a catalyst. A method for producing trisalkylphenyl phosphite, which is characterized in that it is used.

[0011]

[Detailed Description of the Invention]

(Mono- and di-alkylphenol) The mono- and di-alkylphenol as the raw material of the present invention has the general formula (1),

[0012]

[Chemical 1] Is an alkylphenol represented by R ¹ and R ²
Are each independently hydrogen, straight-chain or branched-chain alkyl, cycloalkyl or aryl, except when R ¹ and R ² are both hydrogen.

Examples of alkyl include methyl, ethyl, n-
Propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, n-octyl,
Examples thereof include tertiary octyl, n-nonyl, isononyl, decyl, n-dodecyl, tetradecyl, hexadecyl and octadecyl eicosyl.

Cycloalkyl may be cyclohexylmethyl, methylcyclohexylethyl, etc., and aryl may be alkylphenyl substituted with an alkyl group having 12 or less carbon atoms.

Examples of such monoalkylphenols include 2-methylphenol, 4-methylphenol,
4-methylphenol, 2- or 4-ethylphenol, 2- or 4-propylphenol, 2- or 4-isopropylphenol, 2- or 4-n-butylphenol, 2- or 4-isobutylphenol, 2-or 4 -tert-butylphenol, 2- or 4-pentylphenol, 2- or 4-hexylphenol, 2- or 4-tert-octylphenol, 2- or 4-nonylphenol, 2- or 4-decylphenol, 2- or 4- Examples include dodecylphenol.

Examples of dialkylphenols include 2,4-dimethylphenol, 2,4-diethylphenol, 2,4-dipropylphenol, 2,4-diisopropylphenol, 2,4-din-butylphenol, 2,4-diisobutylphenol, 2,4-ditert-butylphenol, 2,4-dipentylphenol, 2,4-dihexylphenol, 2,4-
Ditert-octylphenol, 2,4-dinonylphenol, 2,4-didecylphenol, 2,4-didodecylphenol and the like can be mentioned.

These alkylphenols may be used as a mixture of two or more kinds.

(Phosphorus trihalide) The phosphorus trihalide used as a raw material in the present invention is preferably phosphorus trichloride. The amount of phosphorus trihalide used is such that the molar ratio of alkylphenol / phosphorus trihalide is 3.00 to 3.20, preferably 3.00 to 3.10.
When the molar ratio is 3.00 or less, the reaction phosphorus trihalide remains,
When the molar ratio exceeds 3.20, the residual amount of unreacted alkylphenol increases.

(Catalyst) The divalent metal oxide used in the present invention is an oxide of a metal belonging to Group 2A of the Periodic Table, among which magnesium oxide, calcium oxide, strontium oxide and the like, particularly magnesium oxide and calcium oxide. Are used, and these may be used alone or as a mixture of two or more kinds.

The amount of catalyst added is 0.01 to 5.00% by weight, preferably 0.05 to 5.00% by weight, based on the starting alkylphenol.
It is 0.50% by weight. If the amount added is less than 0.01% by weight, the catalytic effect is not so great and the reaction is slow. Further, if it exceeds 5.00% by weight, a side reaction may occur.

(Reaction conditions) The method of the present invention can be applied to known methods which meet the purpose. Generally, a mono- or dialkylphenol and a catalyst are charged into a reactor, and 0 to 100
Phosphorus trichloride is slowly added with stirring at a temperature of ℃, preferably 20 to 80 ℃, and aged for 1 to 3 hours. In order to complete the reaction, it is advantageous to raise the temperature to 120 to 150 ° C after aging. Further, at this time, it is desirable to quickly remove the dissolved hydrogen chloride out of the system, and to reduce the pressure in the reaction system,
Alternatively, it is more effective to replace with an inert gas such as nitrogen.

(Solvent) The reaction in the present invention can be carried out without a solvent. However, use of a solvent is advantageous when the starting material alkylphenol has a high melting point. Examples of the solvent used include diethyl ether, tetrahydrofuran, dioxane, hexane, heptane, benzene, toluene, xylene and the like.

(Purification) In the present invention, when the produced phosphite is in a liquid state, the trisalkylphenyl phosphite can be easily isolated by filtration by a usual method. In the production of solid trisalkyl phosphite, the catalyst is removed by filtration, the solvent is removed, and the product is purified by distillation or crystallization.

[0024]

When a 2B group metal such as Zn is added as an oxide to the reaction system, it dissolves in the reaction solution as the reaction progresses, and its catalytic activity is the same as when zinc chloride is added. It is necessary to separate the catalyst as a neutralized salt, and complete separation is difficult.

On the other hand, since the Group 2A metal, when added in the form of chloride, has substantially no catalytic action, it has an excellent catalytic action in the form of oxide and is trihalogenated by the reaction. Hydrogen halide produced from phosphorus does not change into a halide, and can be separated as an oxide by filtration.

[0026]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

Example 1 50 ml of nonylphenol and 0.50 g of magnesium oxide were charged in a 1 L four-necked flask, 100.0 g of phosphorus trichloride was added dropwise at 55 ° C., and the mixture was reacted for 2 hours. Thereafter, the temperature was raised to 125 ° C., and nitrogen gas was blown at a rate of 86.6 ml / min to remove dissolved hydrogen chloride. The acid value of the reaction solution was 0.080 mgKOH / g in 5 hours.
After the reaction was completed, a filter aid was added and filtration under reduced pressure (filtration time 20
Then, the catalyst was removed by distillation to obtain 490.2 g (yield 94.6%) of trisnonylphenylphosphite.

Example 2 The procedure of Example 1 was repeated except that 0.50 g of calcium oxide was used as the catalyst. Acid value of reaction solution is 0.040m after 5 hours
The yield of trisnonylphenyl phosphite was 493.5 g (yield 95.2%) in gKOH / g.

Comparative Example 1 Zinc chloride was used instead of magnesium oxide in Example 1.
Example 1 was repeated except that 0.50 g was charged. The acid value of the reaction solution was 0.20 mgKOH / g after 6 hours of blowing nitrogen gas.
Became. After the reaction was completed, 1.10 g of triethanolamine was added to neutralize the catalyst, and neutral salts were removed by vacuum filtration.
Filtration took 3 hours due to clogging and still the neutral salts could not be completely separated. The yield of trisnonylphenyl phosphite was 404.9 g (78.1% yield).

Example 3 2.4-di tert-butylphenol 500 in a 2 L four neck flask.
0 g, 1000 ml of toluene as a solvent, and calcium oxide.
Charge 50 g and add 106.9 g of phosphorus trichloride dropwise at 40-50 ° C.
After reacting for hours, the mixture was further stirred under reflux of toluene for 2 hours. The acid value of the reaction solution was measured and found to be 0.070 mg KOH / g.

A filter aid was added to this reaction solution, and the mixture was filtered under reduced pressure to remove calcium oxide. The calcium oxide separated by filtration was washed and filtered with 100 ml of toluene, and the filtrate was added to the previous filtrate.

Next, the filtrate was recovered by distilling toluene under a reduced pressure of about 150 mmHg until the liquid temperature reached 120 ° C.
To this residue was added 1000 ml of isopropanol, cooled to 30 ° C., and the precipitated tris 2,4-di tert-butylphenyl phosphite was filtered off under reduced pressure. The obtained crystals were washed with 500 ml of isopropanol and dried to obtain 438.0 g (yield 84.7%) of a product having an mp of 185 to 187 ° C.

Comparative Example 2 The procedure of Example 3 was repeated except that the catalyst calcium oxide was not added (however, the oxidation of the reaction solution was not measured). Wash with 500 ml isopropanol, dry, m.p.
Tris 2,4-di tert-butylphenyl phosphite was obtained as 118.9 g (23% yield) of the product, p. 180-183 ° C.

Example 4 500.0 g of dinonylphenol and 0.50 g of calcium oxide were charged into a 1 L four-necked flask, and 63.3 g of phosphorus trichloride was added dropwise at 55 ° C. and the reaction was carried out for 2 hours. Thereafter, the temperature was raised to 125 ° C., and nitrogen gas was blown at a rate of 85.2 ml / min to remove dissolved hydrogen chloride. The acid value of the reaction solution was 0.070 mgKOH / g after 10 hours.
After completion of the reaction, filtration under reduced pressure (filtration time 20 minutes) was performed to obtain 487.6 g of trisdinonylphenyl phosphite (yield 95.6%).

Comparative Example 3 In Example 4, the calcium oxide catalyst was not added,
Others were the same as in Example 3. Although dissolved hydrogen chloride was removed by blowing nitrogen gas, the acid value of the reaction solution remained at 3.9 mgKOH / g even after 20 hours, and it was confirmed that there was a large amount of unreacted phosphorus trichloride.

[0036]

INDUSTRIAL APPLICABILITY According to the method of the present invention, a trisalkylphenyl phosphite of high purity can be obtained in a high yield with a relatively short reaction time under mild reaction conditions. Also,
A neutralization step is not required to remove the catalyst, and it can be removed by simple filtration, and there is almost no residue in the product.

Claims (1)

[Claims] 1. A method for producing trisalkylphenyl phosphite by reacting phosphorus trihalide with mono- or dialkylphenol in the presence of a catalyst, wherein a divalent metal oxide of Group 2A of the periodic table is used as the catalyst. A method for producing a trisalkylphenyl phosphite, which is characterized by being used.