JPS6257192B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing phosphoric acid alkyl esters.

Currently, phosphoric acid alkyl esters are generally produced as follows. That is, to obtain phosphoric acid monoalkyl esters and phosphoric acid dialkyl esters, phosphorus oxychloride and alcohol are reacted in the presence of a tertiary amine at a molar ratio of 1:1 for the former and 1:2 for the latter, and then reacted with water. Manufactured by reaction and hydrolysis. In addition, to obtain phosphoric acid trialkyl ester, mix phosphorus oxychloride and alcohol in 1 part
It is produced by reacting in the presence of a tertiary amine at a molar ratio of 3. However, this production method requires the use of expensive phosphorus oxychloride as a raw material. This phosphorus oxychloride is generally made from yellow phosphorus obtained by a dry method that consumes more electricity than phosphate rock, and is therefore expensive. On the other hand, in recent years, advances in phosphoric acid production technology have led to the development of a method for producing highly pure phosphoric acid from phosphate ore without passing through yellow phosphorus, that is, without consuming a large amount of energy. became available.

Therefore, the present inventors conducted extensive research on a method for producing an alkyl phosphate ester using such inexpensive phosphoric acid, and as a result, completed the method for producing an alkyl phosphate ester of the present invention.

That is, the method of the present invention is a method for producing a phosphoric acid alkyl ester, which is characterized by reacting phosphoric acid and an alkyl halide in the presence of an amine.

The phosphoric acid used as a raw material in the method of the present invention is 100% hydrated or not.
phosphoric acid can also be used. As the hydrated phosphoric acid, for example, commercially available 75% phosphoric acid or 85% phosphoric acid can be used, and 100% phosphoric acid that does not contain water can be produced from commercially available hydrated phosphoric acid and phosphorus pentoxide. be able to.

Alkyl halides are chlorides, bromides and iodides of _C1 - _C20 straight-chain or branched alkyls, such as -n-butyl chloride, isobutyl chloride, -n-hexyl chloride, -chloride, etc. n-octyl, 2-ethylhexyl chloride, n-lauryl chloride, n-cetyl chloride, n-octadecyl chloride, 1,2-ethane dichloride, ethyl bromide, bromide
n-Butyl, isobutyl bromide, 2-ethylhexyl bromide, n-lauryl bromide, n-cetyl bromide, n-octadecyl bromide, 1,2-ethane dibromide, methyl iodide, iodine Ethyl chloride, iodide-n
-octyl, iodide-n-lauryl-iodide-n
-cetyl, -n-octadecyl iodide, etc.
Although primary and secondary alkyl groups can be used, primary is preferred because it reacts faster.

The amine has the general formula R ₁ NH ₂ R ₁ R ₂ NH R ₁ R ₂ R ₃ N (wherein R ₁ , R ₂ and R ₃ are an alkyl group having 1 to 10 carbon atoms, a phenyl group, an aral group, These are primary amines, secondary amines, tertiary amines, or heterocyclic amines, which represent an alkaryl group and may be the same or different. Among these amines, tertiary amines are particularly preferred. Commonly used amines include triethylamine, tri-n-butylamine, tri-n-
Octylamine, N,N-dimethylaniline,
These include N,N-dimethyltoluidine, N,N-dimethylbenzylamine, and pyridine.

In the method of the present invention, if the raw alkyl halide is used as a solvent, the reaction can be carried out satisfactorily even in the absence of a different type of solvent, but a solvent may be used if necessary. Such solvents include
For example, ethers such as dioxane, dimethoxyethane, diglyme, etc., esters such as methyl acetate, ethyl acetate, butyl acetate, etc., such as methanol, ethanol, isopropyl alcohol, n-
Propyl alcohol, n-butanol, isobutanol, sec-butanol, n-hexanol,
Alcohols such as n-octanol, and N,
N-dimethylformamide, dimethylsulfoxide, hexamethylphosphorotriamide, and the like.

The method for producing a phosphoric acid alkyl ester of the present invention can proceed as follows. Mix phosphoric acid, alkyl halide, and amine and heat. Alternatively, after mixing phosphoric acid and alkyl halide, amine is added dropwise while heating. When using a different type of solvent in addition to the alkyl halide, the solvent and the alkyl halide may be mixed and used in the same manner as the alkyl halide described above. Furthermore, a solvent and phosphoric acid may be mixed first, and the alkyl halide and amine may be simultaneously added dropwise to this mixture while heating.

The heating temperature, heating time, and dropping time vary depending on the type of halogen, but the heating temperature is 40 to 150℃,
The heating time is preferably 30 minutes to 20 hours, and the dropping time is preferably 30 minutes to 10 hours.

The amount of reaction raw materials used is 1 to 30 equivalents of alkyl halide to phosphoric acid when producing monoalkyl phosphoric acid ester, and about 1 equivalent of amine to phosphoric acid, and about 1 equivalent of amine to phosphoric acid when producing dialkyl ester of phosphoric acid. For producing phosphoric acid trialkyl ester, use 2 to 60 equivalents of alkyl halide and about 2 equivalents of amine, and use 3 to 100 equivalents of alkyl halide and 3 to 6 equivalents of amine based on phosphoric acid. .

When using a different type of solvent in addition to the alkyl halide, the amount of solvent used is 1 to 1 to 1 weight of phosphoric acid.
100 times by weight, preferably 1 to 30 times by weight. In the case of producing phosphoric acid monoalkyl esters and dialkyl esters, after the reaction is completed, hydrogen chloride gas is blown into the reaction solution to convert unreacted amine into a hydrogen chloride salt, which can be removed as a precipitate by filtration. This operation of blowing in hydrogen chloride is not necessary when the reaction proceeds quantitatively. Furthermore, hydrogen bromide or hydrogen iodide can also be used instead of hydrogen chloride.

The solvent, excess alkyl halide, and water are removed from the filtrate from which the salt has been removed under reduced pressure to obtain the desired product.
At this time, the product contains phosphoric acid alkyl ester other than the target product and phosphoric acid as a raw material, and if purification is required, the product is converted into an appropriate salt such as aniline salt, cyclohexylamine salt, calcium salt, barium salt, etc., and is recrystallized. Can be purified. Moreover, crystalline compounds can be purified simply by recrystallization.

In the case of phosphoric acid trialkyl ester, the hydrogen halide salt of the amine after the completion of the reaction is removed by filtration, and the solvent and excess amine and alkyl halide are removed from the filtrate under reduced pressure to obtain the desired product. Those that can be distilled by conventional methods are further purified by distillation. Alternatively, after the reaction is complete, remove the solvent under reduced pressure, add water and a solvent such as benzene, toluene, xylene, ether, ethylene chloride, chloroform, or methylene chloride to the residue, mix well, separate the organic layer, and add more as needed. Wash with water, then remove the solvent under reduced pressure.
A phosphoric acid trialkyl ester is obtained. Further, those that can be distilled by conventional methods are purified by distillation. Crystalline compounds of phosphoric acid trialkyl esters can also be purified by recrystallization.

Thus, according to the production method of the present invention, phosphoric acid alkyl esters can be produced in good yield and at a much lower cost than conventional methods using phosphorus oxychloride.

The obtained phosphoric acid alkyl ester can be used as a solvent, a catalyst, a flame retardant, an antistatic agent, a plasticizer, a stabilizer, an anticorrosive agent, an extractant, a lubricating oil additive, and a hydraulic oil.

Next, the present invention will be further explained with reference to Examples. Note that 100% phosphoric acid used in the examples was synthesized by the following method. Commercially available 85% phosphoric acid and 75% phosphoric acid were used.

Synthesis example of 100% phosphoric acid 500g of 85% phosphoric acid was mixed with -10% in an ice-acetone bath.
Cool to ℃ and gradually add phosphorus pentoxide while stirring.
Add 191.5g. After it became a homogeneous liquid, it was left at room temperature for 2 days.

Example 1 57.6 g (0.5 mol) of 85% phosphoric acid was dissolved in 500 g of dimethyl sulfoxide, 67.5 g (0.5 mol) of benzylmethylamine was added to this while cooling to 20°C or less, and 211.4 g (0.6 mol) of cetyl iodide was added. mol) was added, and the mixture was heated and stirred at 70°C for 5 hours. Thereafter, hydrogen chloride was blown into the reaction solution while cooling it to 20° C. or below until no heat was generated. The hydrogen iodide and hydrogen chloride salts of benzylmethylamine were removed by filtration, and then the dimethyl sulfoxide and water were removed under reduced pressure. The residue was crystallized from diethyl ether and then recrystallized from diethyl ether to yield 129 g of mono-n-cetyl phosphate (melting point: 72
°C) was obtained. Yield 80% Elemental analysis C ₁₆ H ₃₅ O ₄ Theoretical value as P (%) C59.60 H10.94 P9.61 Actual value (%) C59.75 H10.85 P9.80 Example 2 100% phosphoric acid 49 g (0.5 mol) was mixed with 743.5 g (5 mol) of -n-octyl chloride, and 92.6 g of tri-n-butylamine was added to this while heating to 100°C.
(0.5 mol) was added dropwise over 2 hours, and then at the same temperature for 3 hours.
heated for an hour. Thereafter, hydrogen chloride was blown into the reaction solution while cooling it to 20° C. or below until no heat was generated. The hydrogen chloride salt of tri-n-butylamine was removed by filtration, then the -n-octyl chloride was removed under reduced pressure, and 250 ml of ethanol and 75 ml of aniline were added to the residue to precipitate the monoaniline salt of n-octyl phosphate. brought about. This was filtered and recrystallized from ethanol to form n-octyl monoanilinium phosphate.
134.2g (melting point 129°-130°C) was obtained. Yield 82% Elemental analysis C ₁₄ H ₂₆ NO ₄ Theoretical value as P (%) C58.71 H8.01 N4.28 P9.46 Actual value (%) C58.56 H8.13 N4.11 P9.51 Implementation Example 3 49 g (0.5 mol) of 100% phosphoric acid was dissolved in 250 g of dimethylformamide, and 185.3 g (1.0 mol) of tri-n-butylamine was added thereto while cooling.
Furthermore, 381.6 g (1.25 mol) of n-cetyl bromide was added, and the mixture was heated at 90°C for 5 hours. Thereafter, hydrogen chloride was blown into the reaction solution while cooling it to 20° C. or below until no heat was generated. Hydrogen bromide and hydrogen chloride of tri-n-butylamine were removed by filtration, dimethylformamide was removed from the filtrate under reduced pressure, the residue was crystallized from diethyl ether, and then recrystallized from diethyl ether to obtain phosphoric acid. G-n
-213.3 g of cetyl (melting point 68°-70°C) was obtained. Yield 78% Elemental analysis C ₃₂ H ₆₇ O ₄ Theoretical value as P (%) C70.28 H12.35 P5.66 Actual value (%) C70.10 H12.15 P5.78 Example 4 85% phosphoric acid 57.6g (0.5mol) of ethyl acetate 1225
g and heated to 60°C. This includes 248.4 g (1.75 moles) of methyl iodide and 138.4 g of pyridine.
(1.75 mol) was simultaneously added dropwise over 1 hour and 30 minutes. At this time, the internal temperature was maintained at 60° to 65°C, and stirring was continued at the same temperature for 1 hour after the completion of the dropwise addition. After the reaction was completed, it was cooled to room temperature, the precipitate of pyridine hydrogen iodide was removed by filtration, ethyl acetate, methyl iodide, pyridine, and water were removed under reduced pressure, and then 66.5 g of trimethyl phosphate (85°C/ 24mm
Hg) was obtained. Yield 95% Elemental analysis Theoretical value as C ₃ H ₉ O ₄ P (%) C25.72 H6.48 P22.11 Actual value (%) C26.00 H6.39 P22.00 Example 5 75% phosphoric acid 65.3g (0.5mol) ethanol 450g
and heated to 80°C. To this, 217.9 g (2.0 mol) of ethyl bromide and 202.4 g of triethylamine
g (2.0 mol) were simultaneously added dropwise over 1 hour. At this time, the internal temperature was maintained at 80° to 85°C, and stirring was continued at the same temperature for 1 hour after the completion of the dropwise addition. After the reaction was completed, the mixture was cooled to room temperature, the precipitated triethylamine hydrogen chloride salt was removed by filtration, and the ethanol, ethyl bromide, triethylamine, and water were removed under reduced pressure, and then 84.6 g of triethyl phosphate (108°C /
25mmHg). Yield 93% Elemental analysis Theoretical value as C ₆ H ₁₅ O ₄ P (%) C39.56 H8.30 P17.60 Actual value (%) C39.30 H8.15 P17.55 Example 6 100% phosphoric acid 49g (0.5 mol) of diglyme 450g
and heated to 120°C. To this, 138.9 g (1.5 mol) of n-butyl chloride and 181.8 g (1.5 mol) of N,N-dimethylaniline were simultaneously added dropwise over 4 hours. At this time, the internal temperature was maintained at 120°-125°C, and stirring was continued at the same temperature for 4 hours after the completion of the dropwise addition. After the reaction was completed, it was cooled to room temperature, the precipitate of the salt of hydrogen chloride of N,N-dimethylaniline was removed by filtration, diglyme was removed under reduced pressure, and 119.7 g of tributyl phosphate (160°-162°C /
15mmHg). Yield 90% Elemental analysis C ₁₂ H ₂₂ O ₄ Theoretical value as P (%) C54.12 H10.22 P11.63 Actual value (%) C54.01 H10.52 P11.60 Example 7 100% phosphoric acid 49 g (0.5 mol) was added to 241.1 g (2.0 mol) of -n-hexyl chloride, mixed by stirring and heated to 130°C. To this, 370.7 g (2.0 mol) of tri-n-butylamine was added dropwise over 4 hours. At this time, the internal temperature was set at 130°-135°C, and stirring was continued at the same temperature for 5 hours after the completion of the dropwise addition. After the reaction was completed, it was cooled to room temperature, the precipitate of tri-n-butylamine hydrogen chloride was removed by filtration, and the tri-n-butylamine hydrogen chloride was removed by filtration.
After removing butylamine and n-hexyl chloride,
Trihexyl phosphate 159.3 g (187
-188°C/2mmHg) was obtained. Yield 91% Elemental analysis C ₁₈ H ₃₉ O ₄ Theoretical value as P (%) C61.69 H11.22 P8.84 Actual value (%) C61.45 H11.15 P8.81 Example 8 100% phosphoric acid 49 g (0.5 mol) of 2-chloride-n-
241.1 g (2.0 mol) of hexyl was added, mixed by stirring, and heated to 130°C. Tori-n-
370.7 g (2.0 mol) of butylamine was added dropwise over 4 hours. At this time, the internal temperature was set at 130° to 135°C, and stirring was continued at the same temperature for 10 hours after the completion of the dropwise addition. After the reaction was completed, it was cooled to room temperature, the precipitate of tri-n-butylamine hydrogen chloride was removed by filtration, and the tri-n-butylamine hydrogen chloride was removed under reduced pressure.
After removing -butylamine and 2-n-hexyl chloride, 143.7 g (179°-180°C/2 mmHg) of tris(2-methylamyl phosphate) was obtained by distillation under reduced pressure. Yield 82% Elemental analysis Theoretical value as C ₁₈ H ₃₉ O ₄ P (%) C61.69 H11.22 P8.84 Actual value (%) C61.70 H11.12 P8.91 Example 9 100% phosphoric acid 49 g (0.5 mol) were added to 4460 g (30 mol) of -n-octyl chloride, mixed by stirring and heated to 130°. 884.2 g (2.5 mol) of tri-n-octylamine was added dropwise to this over 7 hours. At this time, the internal temperature was set at 130° to 135°C, and stirring was continued at the same temperature for 15 hours after the completion of the dropwise addition. After the reaction was completed, the mixture was cooled to room temperature, the precipitated salt of hydrogen chloride of tri-n-octylamine was removed by filtration, tri-n-octylamine and -n-octyl chloride were removed under reduced pressure, and the phosphorus was distilled under reduced pressure. trioctyl acid
193.1g (228°-235°C/2mmHg) was obtained. yield
89% Elemental analysis C ₂₄ H ₅₁ O ₄ As P Theoretical value (%) C66.32 H11.83 P7.13 Actual value (%) C66.15 H11.80 P7.10 Example 10 Butyl chloride 625g (6.75 mol) 100% phosphoric acid 49
(0.5 mol) and 172.0 g (1.7 mol) of triethylamine were added and mixed, and the mixture was heated at 78° to 80° C. for 20 hours. After the reaction was completed, the mixture was cooled to room temperature, and the precipitated triethylamine hydrogen chloride salt was removed by filtration, and triethylamine and butyl chloride were removed under reduced pressure. Next, 113 g (160 g) of tributyl phosphate was distilled under reduced pressure.
~162°C/15mmHg) was obtained. Yield 85% Elemental analysis C ₁₂ H ₂₇ O ₄ Theoretical value as P (%) C54.12 H10.22 P11.63 Actual value (%) C54.22 H10.15 P11.56 Example 11 75% phosphoric acid 65.3g (0.5mol) was dissolved in 500ml of dimethylformamide, and while cooling to below 20℃, 556.0g (3mol) of tri-n-butylamine was added, and further 782.7g (3mol) of cetyl chloride was added. The mixture was heated and stirred at ℃ for 18 hours.
Thereafter, the hydrogen salt of tributylamine was removed by filtration, and dimethylformamide, water and excess tri-n-butylamine were further removed under reduced pressure. The residue was crystallized from ligroin and then recrystallized from ligroin to obtain tri-n-cetyl phosphate.
327.8g (melting point 61°C) was obtained. Yield 85% Elemental analysis C ₄₈ H ₉₉ O ₄ Theoretical value as P (%) C74.75 H12.94 P4.02 Actual value (%) C74.63 H12.85 P4.11 Example 12 1,2- 100 in 3463g (35mol) of ethane dichloride
% phosphoric acid 49g (0.5 mole) and triethylamine
151.8 g was added, mixed, and heated under reflux for 15 hours.
After the reaction was completed, the reaction mixture was cooled to room temperature, and the precipitated salt of erethylamine hydrogen chloride was removed by filtration, and 1,2-dichloroethane was removed under reduced pressure. Next, by vacuum distillation, tris(2-chloroethyl phosphate) 95.2
g (180°C/5mmHg). Yield 86% Elemental analysis C ₆ −H ₁₂ Cl ₃ O ₄ P Theoretical value (%) C32.54 H5.46 Cl48.02 P13.98 Actual value (%) C32.40 H5.51Cl48.00 P14.01.

Claims (1)

[Claims] 1. A method for producing a phosphoric acid alkyl ester, which comprises reacting phosphoric acid and an alkyl halide in the presence of an amine.