JPH0215558B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing phosphonitrile esters. More specifically, the present invention relates to a method for producing a phosphonitrile ester having low acidity and a reduced amount of residual halogen atoms. Phosphonitrile esters include polyurethane, polyester, polyolefin, vinyl polymer, polyacrylate, polymethacrylate, neorene, natural rubber, butadiene-styrene copolymer,
It is a useful compound that can add flame retardancy, heat resistance, etc. to a polymer compound such as regenerated cellulose by forming a copolymer with the polymer compound, or by simply mixing the compound. Phosphonitrile esters are generally produced by reacting phosphonitrile halides with alcohols in the presence of dehydrohalogenating agents. The dehydrohalogenating agents used in these conventional methods are (1) alkali metal hydroxides such as sodium hydroxide, (2) alkali metal carbonates such as sodium carbonate, or (3) pyridine. Basic substances such as tertiary amines represented by However, the method (1) using an alkali metal hydroxide has the disadvantage that the reaction product is very acidic and that the strong basicity of the alkali metal hydroxide decomposes the raw material phosphonitrile halide. , so it is unsuitable for production on an industrial scale. The method (2) using an alkali metal carbonate has the following advantages compared to the method (1) using an alkali metal hydroxide:
The acidity of the resulting phosphonitrile ester can be reduced considerably. However, due to the presence of water produced as a by-product during the reaction, a highly viscous by-product having a P-O-P bond, which is thought to be produced according to the following reaction formula, is mixed in, which is not preferable. Furthermore, in method (2), the acidity of the reaction product cannot be reduced to a sufficiently satisfactory level due to the P-OH group found in the intermediate of the above reaction formula. In the method (3) using a tertiary amine, the dehydrohalogenating agent is more expensive than the methods (1) and (2), and the alcohol used is a polyhydric alcohol, so the target product is water-soluble. This makes it difficult to remove the tertiary amine, and the removed tertiary amine is partially or mostly converted to hydrohalide, so reuse requires steps such as alkali treatment and distillation. There are disadvantages such as requiring In addition, since relatively many unsubstituted chlorine atoms remain in the phosphonitrile ester obtained by the conventional method described above, when used as a polyol for urethane, for example, unsubstituted chlorine atoms remain in the phosphonitrile ester. This is not preferable because it becomes a halogen component contained in the polyurethane and causes deterioration of the polyurethane due to changes over time and further corrosion of surrounding materials. Therefore, it is generally important to reduce as much as possible unsubstituted halogen atoms, which are a factor in forming active halides. As a result of extensive research in view of the current situation, the present inventors have discovered that by reacting phosphonitrile halide with dihydric or higher alcohol without using a dehydrohalogenating agent, the hydrogen halide generated during the reaction is reacted sequentially. The present inventors discovered that the conventional drawbacks could be overcome by releasing the compound to the outside of the system, and completed the present invention. It is often thought that if a dehydrohalogenating agent is not used, the raw material or target compound will be decomposed by the generated hydrogen halide, or the reaction will not proceed as quickly, but according to the present invention, the raw material or target compound It was found that the compound was hardly decomposed and the reaction proceeded smoothly. In addition, the acid value of the product (the weight (mg) of potassium hydroxide required to neutralize the P-OH group in 1 g of sample) is lower than that of the conventional method, and the product is more highly esterified. Ta. Hydrogen halide produced during the reaction can be more easily removed by blowing an inert gas into the reaction solution. Blowing may be carried out by bubbling the reaction liquid or by passing a gas over the reaction liquid, but the latter method usually provides sufficient effects. The phosphonitrile halide used in the present invention is not particularly limited, but for example,
A mixture of trimer and tetramer phosphazene oligomers (weight ratio 85:15 to 75:25) produced according to the method disclosed in JP-A No. 145395 or JP-A-54-145395, or Examples include macrocyclic phosphazene oligomers and linear phosphazene oligomers. Examples of the alcohol include ethylene glycol, propylene glycol, 1,4-butanediol, 2,2-dimethyl-1,3-propanediol, pentane-2,4-diol, 3-
Glycols such as methylpentane-2,5-diol, dihydric alcohols such as polyoxyalkylene glycols such as diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, and polypropylene glycol, or glycerol, pentaerythritol, sorbitol, etc. Examples include polyhydric alcohols having three or more hydroxyl groups. Preferred alcohols from the viewpoint of ease of handling and yield of the resulting reaction product are 2,2-dimethyl-1,3-propanediol and dipropylene glycol. The use of monovalent lower aliphatic alcohols such as methanol, ethanol, propanol, and butanol is not preferred because the reaction involves decomposition of phosphonitrile. By the way, a small amount of these monohydric alcohols can be mixed with dihydric alcohols or monohydric alcohols.
When used in combination with higher alcohols, the decomposition can be suppressed to a non-problematic level. In addition, although the content of unsubstituted halogen atoms can be reduced to about 1 to 5% by the method described above, the product obtained by the method may also contain metal alcoholates, ammonia, primary amines or secondary halogen atoms. By adding and reacting with grade amine,
It is possible to obtain a phosphonitrile acid ester in which almost no unsubstituted halogen atoms remain (unsubstituted halogen atom content less than 0.1%). Specific examples of metal alcoholates that can be used include:
For example, sodium methylate, ethylate,
n-propyl alcoholate, isopropyl alcoholate, phenolate, p-chlorophenolate, 1,1,1-trifluoroethylate, octafluoropropylmethyl alcoholate, o-methylphenolate, m-methylphenolate, p
Among them, sodium methylate, n-propyl alcoholate, 1,1,1-trifluoroethylate or phenolate are preferred, and are added as such or as an alcoholic or tetrahydrofuran solution. Specific examples of primary or secondary amine compounds that can be used include methylamine, ethylamine, propylamine, isopropylamine, aniline, dimethylamine, diethylamine, and dipropylamine, which may be used as is or benzene, It is added after being dissolved in an aromatic hydrocarbon solvent such as toluene or xylene. The reaction between phosphonitrile halide and alcohol is carried out in the presence of a solvent or without a solvent at a reaction temperature of 70 to 180 °C.
C., preferably 85 to 135.degree. C., for 5 to 30 hours. By keeping the temperature of the reaction solution at a high temperature as described above, most of the generated hydrogen halide gas can be discharged out of the reaction system and removed by the spontaneous exhaust gas pressure. The removal of this hydrogen halide gas is
For example, this can be carried out more smoothly by bubbling an inert gas into the reaction liquid or passing it over the reaction liquid. The solvent is added for the purpose of uniformly proceeding the reaction by washing away unreacted phosphazene oligomers and/or crystalline alcohol that precipitate at the top of the reaction vessel due to sublimation in the early stage of the reaction. As such a solvent, aromatic hydrocarbon solvents such as benzene, toluene, xylene, and chlorobenzene are preferred. The reaction of replacing the unreacted halogen remaining in the reaction product with the alcoholate compound or amine compound is carried out at room temperature or the boiling point temperature of the solvent used for 3 to 8 hours. The alcoholate solution was added at room temperature, then stirred at room temperature for 1-5 hours, and then stirred for an additional 50-100 hours to complete the reaction.
Preferably, the reaction is carried out at a temperature of 0.5 to 2 hours. When an amine compound is used, reaction conditions are appropriately selected depending on the reactivity and physical properties of the amine compound. Next, the present invention will be explained in more detail by reference examples, working examples, and comparative examples, but the present invention is not limited only to these examples. Reference example 1 500 ml of monochlorobenzene and ammonium chloride were placed in a flask equipped with a reflux condenser, thermometer, stirrer, phosphorus trichloride dropper, and chlorine gas blowing tube.
A mixed dispersion was obtained by charging 36.5 g (0.68 mol) and 0.5 g of zinc oxide. The dispersion was heated to a temperature of 130°C, and under reflux, 85.1 g of phosphorus trichloride was added dropwise at a rate of 0.89 g/min over 96 minutes, and at the same time, 45.4 g of chlorine gas was added at a rate of 0.47 g/min over 96 minutes. It was supplied across the board. After supplying phosphorus trichloride and chlorine gas, reflux (132°C) was further performed for 144 minutes to complete the reaction. Then, unreacted ammonium chloride was removed by suction, and monochlorobenzene was distilled off from the liquid at 30 to 40°C under a reduced pressure of 10 to 20 mmHg to obtain 70.4 g of a reaction product. The yield of the reaction product was 98.1% based on phosphorus trichloride. A cyclic phosphazene oligomer was extracted from the reaction product with petroleum ether. The yield of cyclic phosphazene oligomer after distilling off the petroleum ether was 68.3 g. The crystalline trimers and tetramers and the oily macrocyclic phosphazene oligomers are separated by suction filtration to obtain the crystalline trimers and tetramers phosphazene oligomers.
I gained 64.5g. Example 1 312 g (3 mol) of 2,2-dimethyl-1,3-propanediol was placed in a four-necked flask equipped with a stirring bar, thermometer, reflux condenser, and gas introduction tube.
and 116 g (1/3 mole or 1 unit mole) of phosphonitrile chloride trimer were weighed out and reacted by heating and stirring at 90 to 100° C. for 20 hours in a nitrogen gas stream. After the reaction is complete, add tetrahydrofuran to the product.
500 ml of unreacted 2,2-
300 g of a viscous, pale yellow oil containing dimethyl-1,3-propanediol was obtained. This oily substance is detected by Hiranuma automatic titration equipment (silver nitrate titration).
As a result of analysis using a Hitachi absorbance measuring device, the unsubstituted chlorine content was 2.1% and the phosphorus content was 9.5%. In addition, the acid value and hydroxyl value measured by the JIS K 1557 polyurethane test method were 7.1KOHmg/g and 250KOHmg/g, respectively.
It was hot at g. Example 2 In place of phosphonitrile chloride trimer, Reference Example 1
Example 1 except that 116 g of a mixture of phosphonitrile chloride trimer and tetramer prepared by the method of Example 1 was used.
An experiment was carried out in the same manner as above, and a viscous slightly yellow oil was obtained.
I gained 305g. The analysis results of the obtained oil are shown in Table 1. Example 3 Instead of phosphonitrile chloride trimer, Reference Example 1
Phosphonitrile chloride cyclic oligomer produced by the method without separating the trimeric and tetrameric crystalline components
The experiment was carried out in the same manner as in Example 1, except that 116 g was used, and 295 g of a viscous, pale yellow oil was obtained. The analysis results of the obtained oil are shown in Table 1. Example 4 An experiment was carried out in the same manner as in Example 1, except that 403 g (3 mol) of dipropylene glycol was used instead of 2,2-dimethyl-1,3-propanediol, and a viscous slightly yellow oil was obtained. I gained 302g. The analysis results of the obtained oil are shown in Table 1. Comparative Example 1 268 g (1 mol) of dipropylene glycol and potassium carbonate were placed in a 4-necked flask equipped with a stirring bar, thermometer, reflux condenser, and calcium chloride tube.
276 g (2 mol) was weighed out, and a solution of 116 g (1 unit mol) of chlorinated phosphonitrile halide trimer dissolved in 400 ml of benzene was added dropwise over about 2 hours. The reaction solution was further heated under reflux for 20 hours to complete the reaction. After cooling the reaction solution, 500 ml of benzene was added, and then the insoluble inorganic residue was removed by filtration. Since the liquid was slightly cloudy due to ultrafine inorganic residues, it was further subjected to precision filtration using No. 5C paper with a filter aid to completely remove the inorganic residues. The liquid was concentrated under reduced pressure to obtain 210 g of a viscous, pale yellow oil. The analysis results of the obtained oil are shown in Table 1.

[Table] Example 6 An experiment was conducted in the same manner as in Example 5, except that the amount of 2,2-dimethyl-1,3-propanediol used was changed to 104 g (1 mol), and the reaction time was changed to 7 hours. 165 g of a slightly yellow waxy product was obtained. The unsubstituted chlorine content of the obtained oil was 19.5%. Example 7 A methanol solution of 28% sodium methylate was added to the untreated reaction solution obtained by the method of Example 6 above.
193 g (1 mol as sodium methylate) was added dropwise at room temperature over 1 hour. Although the reaction was exothermic, it was allowed to cool for 15 hours without cooling, with the natural reflux temperature being the upper limit temperature. After the reaction is complete, excess sodium methylate is
A 35% aqueous hydrochloric acid solution was added little by little to neutralize, and insoluble inorganic substances were removed by filtration. The liquid was then concentrated under reduced pressure to obtain 150 g of a viscous, pale yellow oil. The analysis results of the obtained oil are shown in Table 2. Example 8 After diluting the untreated reaction solution obtained by the method of Example 6 by adding 100 g of toluene, about 2 moles of ammonia gas was blown into it at room temperature over 5 hours, and then further at room temperature for 2 hours. Stirred. The ammonium chloride crystals formed are removed by filtration.
The liquid was concentrated under reduced pressure to obtain 135 g of a viscous slightly yellow oil. The analysis results of the obtained oil are shown in Table 2. Example 9 122 g of sodium trifluoroethylate was added to the untreated reaction solution obtained by the method of Example 6.
A solution dissolved in 488 g of THF was added dropwise at room temperature over 2 hours. Although the reaction was exothermic, it was allowed to cool to the natural reflux temperature as an upper limit without cooling for 15 hours. After the reaction was completed, excess sodium trifluoroethylate was neutralized by adding 35% aqueous hydrochloric acid solution little by little, and insoluble inorganic substances were removed by filtration. The liquid was then concentrated under reduced pressure to obtain 145 g of a viscous, pale yellow oil. The analysis results of the obtained oil are shown in Table 2. Example 10 The untreated reaction solution obtained by the method of Example 6 was diluted by adding 100 g of toluene, and then 186 g (3 moles) of aniline was added at room temperature, followed by stirring for 5 hours to complete the reaction. Insoluble matter believed to be aniline hydrochloride was removed by filtration, and the liquid was concentrated under reduced pressure to obtain 142 g of a viscous brown oil. The analysis results of the obtained oil are shown in Table 2.

[Table] Example 11 134 g (1 mol) of dipropylene glycol in place of 2,2-dimethyl-1,3-propanediol
The experiment was carried out in the same manner as in Example 6 except that 193 g of a pale yellow oil was obtained. The unsubstituted chlorine content of the obtained oil was 18.5%. Example 12 A methanol solution of 28% sodium methylate was added to the untreated reaction solution obtained by the method of Example 11 above.
193 g (1 mol as sodium methylate) was added dropwise at room temperature over 1 hour. Although the reaction was exothermic, it was allowed to cool for 15 hours without cooling, with the natural reflux temperature being the upper limit temperature. The treatment after the completion of the reaction was carried out in the same manner as in Example 7, and 182 g of a viscous, pale yellow oil was obtained. Analysis of the obtained oil revealed that the unsubstituted chlorine content was 0.04% and the phosphorus content was 12.5%. Also, the acid value is 3.5KOHmg/g, and the hydroxyl value is 118KOHmg/g.
It was hot.

Claims (1)

[Claims] 1. A method characterized in that the reaction between a phosphonitrile halide and a dihydric or higher alcohol is carried out in the absence of a dehydrohalogenating agent, and the generated hydrogen halide is sequentially removed from the reaction solution. A method for producing a phosphonitrile ester. 2. The reaction between phosphonitrile halide and dihydric or higher alcohol is carried out in the absence of a dehydrohalogenating agent by a method in which the generated hydrogen halide is sequentially removed from the reaction solution, and then the metal alcoholate, ammonia, and A method for producing a phosphonitrile acid ester with a low content of unsubstituted halogen atoms, which comprises adding a primary amine or a secondary amine. 3. The manufacturing method according to claim 2, wherein the metal alcoholate is sodium methylate, sodium n-propyl alcoholate, sodium, 1,1,1-trifluoroethylate, or sodium phenolate. 4 The primary amine or secondary amine is methylamine, ethylamine, propylamine, isopropylamine, butylamine, amylamine,
Hexylamine, hebutylamine, allylamine, aniline, O-toluidine, m-toluidine, p-toluidine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, diamylamine or diallylamine, methylaniline The manufacturing method described in Section 2.