JPS5851883B2 - Method for producing cyclic phosphonitrile chloride oligomer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing cyclic phosphonitrile chloride oligomers.

The cyclic phosphonitrile chloride oligomer has the general formula (P
NC12) It is an oligomer represented by n (n=an integer of about 3 to 7), and this oligomer is attracting attention as a raw material for phosphazene polymer, which is an inorganic polymer compound.

The phosphazene polymer is produced by ring-opening polymerization of the above-mentioned cyclic phosphonitrile chloride oligomer, particularly preferably its trimer (hexachlorocyclotriphosphazene) to form a chain polydichlorophosphazene, and substituting the chlorine with various substituents. It is expected that various types of polymers and polymers with a wide range of properties can be produced depending on the types of substituents.

Properties of such phosphazene polymers include, for example, flame retardancy, water repellency, flexibility at low temperatures, chemical resistance, electrical insulation, and biocompatibility.

Recently, research has been actively conducted on the application of elastomers, paints, foams, etc. having the above-mentioned properties.

Cyclic phosphonitrile chloride oligomer (a raw material for phosphazene polymer with such excellent properties)
The production of PNC (hereinafter simply abbreviated as PNC) has been actively carried out, but all the methods so far have had drawbacks such as coloring of the resulting polymer, gel raw skin, low degree of polymerization, and wide molecular weight distribution. However, there has been no method to provide PNC with excellent polymerization properties.

Furthermore, a characteristic phenomenon of conventional methods for obtaining phosphazene polymers by polymerizing PNC is the fact that the properties of the obtained polymers are not constant, and it is extremely difficult to obtain polymers with good reproducibility in terms of properties.

Therefore, research is being conducted on methods to improve polymerization properties by purifying crude PNC, but conventional methods result in an extremely large loss of PNC in the purification process, and even if purified PNC is used for polymerization, the polymer still obtained However, the properties of the polymer are insufficient, and the properties of the polymer are not constant, making it impossible to obtain a polymer with excellent reproducibility.

For example, US Patent No. 3,669,633 discloses that ammonium chloride and PCl5 are reacted in an organic solvent inert to the reaction, and a solution of the resulting reaction mixture in the organic solvent is heated at 75 to 100°C.
After washing with water at a temperature of
A method for obtaining NC is described, but in this case, separation of the aqueous layer and organic layer is poor, the recovery rate of PNC is as low as 86%, and the properties of the polymer obtained from this PNC are insufficient, and it is difficult to reproduce the properties. There is no sex.

Furthermore, the purification method described in U.S. Pat. No. 3,694,171, like the method described in the above-mentioned U.S. patent, has a low recovery rate of PNC, and the properties of the polymer obtained from this PNC are also insufficient and non-reproducible. .

That is, in this method, a mixed solution of PNC and an organic solvent inert to chlorination obtained after the reaction is brought into contact with an aqueous solution of caustic soda, etc. to obtain PNC consisting of trimers and tetramers. The recovery rate of PNC is about 60%, and an extremely large amount of PNC is lost.

Furthermore, JP-A-54-142195 describes a method of washing crude PNC with water at least twice at room temperature for Japanese preparation, but even with this method, the recovery rate of PNC was 63.5%.
The properties of the polymer obtained from this PNC are also low, and the properties of the polymer obtained from this PNC are also inconsistent, resulting in a lack of reproducibility.

The purpose of the present invention is to have no coloring, substantially no gel formation,
PNC with extremely excellent polymerization properties that can provide phosphazene polymers with excellent properties such as high degree of polymerization and narrow molecular weight distribution.
The objective is to provide a manufacturing method.

Another object of the present invention is to obtain a PNC with excellent polymerization properties that provides the above-mentioned phosphazene polymer with excellent properties with extremely high reproducibility.
The objective is to provide a manufacturing method.

Another object of the present invention is that there is almost no loss of PNC in the purification process performed for the purpose of improving polymerization properties, and almost 100% of PNC is lost.
An object of the present invention is to provide a method for producing PNC that can recover PNC at a recovery rate of .

The present invention consists of (4) reacting phosphorus pentachloride and ammonium chloride in an organic solvent inert to chlorination in the presence of one or more catalysts of organic acid salts of divalent metals; A first step of distilling off the reaction solvent to obtain a reaction product consisting essentially of a cyclic phosphonitrile chloride oligomer; and (B) converting the reaction product to one or more solvents selected from aliphatic hydrocarbons and ethers. The solution dissolved in about 4
It is brought into contact with water at a temperature of 0 to 100°C, and then separated into an aqueous layer and an organic layer, and from the organic layer, a cyclic phosphonitrile flora/f-oligomer with excellent polymerization properties mainly composed of trimers and tetramers is obtained. The present invention relates to a method for producing a cyclic phosphonitrile chloride oligomer, which is characterized in that a second step of recovery is combined.

Examples of the organic solvent inert to chlorination used in the first step of the present invention include tetrachloroethane, tetrachloroethylene, monochlorobenzene, dichlorobenzene, and the like.

As the catalyst, an organic acid salt of a divalent metal is used.

As divalent metals, various metals belonging to groups ① to ① of the periodic table are used, among which group ① such as Mg and Zn,
Group Ⅰ metals such as Mn and group Ⅰ metals such as Co and Ni are preferred.

As the organic acid, aliphatic or aromatic mono- to trivalent carboxylic acids with or without substituents can be used.

Suitable aliphatic carboxylic acids include those having 1 to 24 carbon atoms, preferably 2 to 18 carbon atoms, such as acetic acid, propionic acid, lauric acid, caprylic acid, stearic acid, oleic acid, oxalic acid, and succinic acid. , citric acid, lactic acid, L-aspartic acid, and the like.

The aromatic carboxylic acid preferably has 7 to 15 carbon atoms, preferably 7 to 10 carbon atoms, and specific examples include benzoic acid, salicylic acid, and terephthalic acid.

When such an organic acid salt of a divalent metal is used as a catalyst,
It has the feature that the trimer content is increased by about 3 to 5% compared to the corresponding divalent metal chloride.

In the first step of the reaction of the present invention, ammonium chloride and phosphorus pentachloride are reacted in the presence of the catalyst described above in the organic solvent described above.

It is preferable to use ammonium chloride in excess of phosphorus pentachloride, and usually 1 to 1.5 mol of the former is used per 1 mol of the latter.

The amount of the catalyst to be used is also not particularly limited, but it is usually about 1 to 10-5 mol, preferably about 10-2 to 10-5 mol, per 1 mol of phosphorus pentachloride.
It is preferable to use 10-4 mol.

Further, as the phosphorus pentachloride, one obtained by reacting phosphorus trichloride and chlorine may be used.

The reaction can be carried out by various methods, but preferably, for example, ammonium chloride and a catalyst are added to a reaction solvent, and a solution of phosphorus pentachloride in an organic solvent is added dropwise thereto while stirring.

The reaction temperature is not particularly limited, but is usually 100 to 200°C.
, preferably from a range of about 120 to 145°C.

The reaction ends when hydrogen chloride gas produced by the reaction between phosphorus pentachloride and ammonium chloride is no longer generated, and then excess ammonium chloride is removed by filtration and the solvent is distilled off to form a reaction product consisting essentially of PNC. get something

PNC, which is the target product in the first step of the present invention, means a cyclic phosphonitrile chloride oligomer represented by the general formula (PNC12) n, where n = an integer of 3 to 7, and substantially consists of PNC in the first step. The reaction product is one consisting of a compound represented by (PNC12) n, an integer of n = 3 to 7, and even if it contains compounds other than the above, such as linear phosphazene oligomers, 1 weight %, preferably less than 0.5% by weight.

When the reaction product obtained in the first step of the present invention does not substantially consist of PNC in the above sense, it is difficult to obtain the desired PNC with excellent polymerization suitability in the subsequent second step with a high recovery rate. It is therefore essential to obtain a reaction product consisting essentially of PNC in the first step.

In order to obtain such a reaction product, it is essential to use an organic acid salt of a divalent metal as a catalyst.

Next, the reaction product is dissolved in one or more solvents selected from aliphatic hydrocarbons and ethers.

Aliphatic hydrocarbons include petroleum ether, petroleum benzene,
Hydrocarbons having 5 to 12 carbon atoms, such as n-hexane, n-hebutane, n-octane, and isooctane, are particularly effective.

Examples of the ethers include dibutyl ether and butyl ethyl ether.

The amount of solvent may be determined as appropriate, but it is usually desirable to use an amount equal to or twice the weight of the reaction product.

Next, the above solution is heated to about 40-100°C, preferably about 50-100°C.
Contact with water is carried out at a temperature of 95°C, particularly preferably about 70-90°C.

In general, PNC is considered to be unstable in water, and many prior art purification methods for crude PNC tend to avoid the use of water, and when water is used, the recovery rate of PNC is poor. Contrary to such prior art, the present invention has an extremely high recovery rate of PNC even though it is brought into contact with water at a relatively high temperature.

In the present invention, after the water washing is completed, the aqueous layer is separated and removed, the solvent is distilled off from the organic layer, and the target PNC containing 3 and the heavy body as main components is purified by distillation, sublimation, recrystallization, etc. Collected by

Here, PNC whose main component is 3 and heavy body is usually 90
Contains at least 3 wt%, preferably at least 95 wt%, of 3 and heavy bodies, and additionally contains pentamers and heptamers,
It is preferable that the amount of such pentamer to heptamer be small.

By the above method, it is possible to obtain a PNC having extremely excellent polymerization properties that yields a phosphazene polymer having the above-mentioned excellent properties with good reproducibility.

The PNC obtained in the present invention can be polymerized according to various known methods, such as bulk polymerization, solution polymerization, etc.

The phosphazene polymer obtained by such polymerization has no coloration, virtually no gel formation, high degree of polymerization, sharp molecular weight distribution, etc., and the polymer with such excellent properties can be obtained with extremely good reproducibility. be able to.

The present invention will be described below with reference to Examples.

In the following, the term % simply indicates weight %.

Example 1 231 g (4.3 mol) of ammonium chloride was placed in a 31-meter three-way flask equipped with a stirrer, a cooling tube, and a dropping funnel.
Zinc acetate (CHs
COO) 23.679 (2X 10-2rnol
), prepare 350g of monochlorobenzene, 125~1
Phosphorus pentachloride 7509 (3,6 mol) at a temperature of 35 °C
1650 g of a monochlorobenzene solution was added dropwise over 16 hours.

After the completion of the dropwise addition, the reaction is carried out for 2 hours, and after the completion of the reaction, unreacted ammonium chloride is removed in a separate furnace, and the reaction solvent is distilled off.

As a result, 375.9 g of reaction product (9
A yield of 0.1%) was obtained.

Gas chromatography shows that 59.9% of trimers and 24.1% of tetramers are present.
%, 16.0% of pentamers and 100% of cyclics.

After that, n-hebutane (570 g) was added to the above reaction product, dissolved, washed with an equal amount of water at around 80°C, the aqueous layer was separated and removed, and crude PNC375, 1 g was extracted from the n-hebutane layer.
(Yield of 89.9% based on phosphorus pentachloride, recovery rate of 99.79% in the water washing step) was obtained.

Gas chromatography analysis shows 60.0% trimer and 24.1% tetramer.
, the pentamer content was 15.9%.

The crude PNC obtained in this way is distilled under reduced pressure to obtain purified PNC.
199, Og was obtained (trimer 9 was determined by gas chromatography).
8.6%, tetramer 1.4%).

This purified PNC was charged into a polymerization tube, the tube was degassed and sealed under a reduced pressure of 10'' mmHg, and polymerization was performed at 250°C.

As a result, polymerization occurred without gelation, and the conversion rate was 25% in 28 hours.
%, and the obtained polymer has an intrinsic viscosity of 1.02c//
/g, Mn=3.53X10', Mw=9
．． It showed good polymerization properties with 97X 10' and Mw/Mn=2.8.

Comparative Example 1 Zinc chloride 2.45 & (2X 10”m
PNC was obtained in the same manner as in Example 1 using PNC.

The reaction product is 387.19 (92.8 for phosphorus pentachloride)
% yield) was obtained, and gas chromatography showed that the trimer was 56.
2%, tetramer 26.4%, 5% heptamer 17.4%, and cyclics 100%.

After washing with water, crude PNC386,09 (92% for phosphorus pentachloride)
．． The yield was 6%, and the recovery rate after washing with water was 99.7%).

The crude PNC obtained in this way was distilled to produce purified PNC20.
0.2p (gas chromatography measurement, trimer 9465%, tetramer 5
．． 2%, pentamer 0.3%).

Example 2 Magnesium acetate 2.89 (2X10-2
mol) in the same manner as in Example 1 to obtain PNC.

The reaction product is 376.49 (90.2% based on phosphorus pentachloride)
A yield of 71.2% of the trimer was obtained by gas chromatography.
%, tetramer 17.0%, pentamer heptamer 11.8%, and cyclics 100%.

After washing with water, crude PNC375,39 (89 for phosphorus pentachloride)
．． The yield was 9%, and the recovery rate after washing with water was 99.7%).

The crude PNC obtained in this way was distilled, and the purified PNC2
82.5 g (gas chromatography measurement: 87.1% trimer, 11.2% tetramer, 1.8% pentamer) was obtained.

Polymerization properties were investigated using the method described in Example 1.

As a result, polymerization occurred without gelation or coloring, and the conversion rate was 25% in 22.5 hours, and the resulting polymer had an intrinsic viscosity of 1, 45 cll/fit Mr1=4. IX1
05. Mvv = 2.2 Xl 0', Mw/
It showed good polymerization properties with Mn = 5.4.

Comparative Example 2 Magnesium chloride as a catalyst 11.9. ! 9 (2X10
-2 mol) was used in the same manner as in Example 1 to obtain PNC.

The reaction product is 381.29 (91.4% based on phosphorus pentachloride)
A yield of 69.0% of the trimer was obtained by gas chromatography.
%, tetramer 19.0%, pentamer heptamer 12.0%, and cyclics 100%.

After washing with water, crude PNC380, 91 for 19C phosphorus pentachloride
．． The yield was 1%, and the recovery rate after washing with water was 99.7%).

The crude PNC obtained in this way was distilled to produce purified PNC28.
0.89 (gas chromatography measurement, trimer 85.1%, tetramer 1
0.2%, pentamer 4.7%).

Example 3 Cobalt stearate (C17H35α
D) Example 1 using sym-tetrachloroethane as solvent using 212.49 (2X 10-2 mol)
PNC was obtained in the same manner.

The reaction product is 385.09 (92.3% based on phosphorus pentachloride)
A yield of 70.2% of the trimer was obtained by gas chromatography.
%, tetramer 17.2%, pentamer 12.5%, and cyclics 100%.

After washing with water, the crude PNC383,0,! The yield was 91.8% based on l' phosphorus pentachloride, and the recovery rate after washing with water was 99.48%).

The crude PNC thus obtained was distilled to produce purified PNC25.
5.7g (Gas chromatography measurement, trimer 97.1%, tetramer 2
．． 9%).

Polymerization properties were investigated using the method described in Example 1.

As a result, polymerization occurred without gelation or coloring, and the conversion rate was 25% in 22 hours, and the obtained polymer had an intrinsic viscosity of 1.70.
di/9.

Mn=5.27X10', Mw=2.64X10',
It showed good polymerizability with Mw/Mn = 5.0.

Comparative Example 3 Cobalt chloride 2.69 (2X 10-2m
PNC was obtained by the method described in Example 3 using PNC.ol).

The reaction product is 3ss,o,9 (93.0 for phosphorus pentachloride
% yield) was obtained, and gas chromatography showed that the trimer was 65.
8%, tetramer 19.3%, pentamer 14.9%, and cyclic substances 100%.

After washing with water, the crude PNC387,0,! 9 (92.8% yield based on phosphorus pentachloride, 99.74% recovery rate during water washing process)
Met.

The crude PNC obtained in this way is distilled under reduced pressure to obtain purified PNC.
250 g was obtained (96.9 g of trimer was determined by gas chromatography).
0%, tetramer 4.0%).

Examples 4 to 10 Magnesium stearate (Mg(C,ヮH,,COO)9), magnesium benzoate [Mg(C6H5COO)2], magnesium L-aspartate [Mg(C4H6NO4)2], oxalic acid as catalysts Nickel (N t C204), magnesium succinate [Mg(C2H202)2], manganese succinate (M
PNC was obtained in the same manner as in Example 1 using 2×10 −2 m01 of n (C2H202)2'l and magnesium citrate, respectively.

The results are shown in Table 1 below.

Claims (1)

[Claims] 1(A) Phosphorous pentachloride and ammonium chloride are reacted in an organic solvent inert to chlorination in the presence of one or more catalysts of organic acid salts of divalent metals. , a first step in which the reaction solvent is distilled off after the completion of the reaction to obtain a reaction product consisting essentially of a cyclic phosphonitrile chloride oligomer; Approximately 4 ml of solution containing one or more
The second step involves contacting with water at a temperature of 0 to 100°C, then separating into an aqueous layer and an organic layer, and recovering from the organic layer a cyclic phosphonitrile chloride oligomer having excellent polymerization properties and mainly composed of trimers and tetramers. A method for producing a cyclic phosphonitrile flora ide oligomer, characterized by combining steps.