JP2816760B2 - Method for producing bis (alkylcyclohexyl) phosphoric acid - Google Patents

Description

The present invention relates to an efficient method for producing bis (alkylcyclohexyl) phosphoric acid.

[Conventional technology and its problems]

Conventionally, as a method for producing a usual secondary organic phosphate, a method according to the following reaction formula is described in, for example, P.595 of Organic Chemistry Handbook and is known as a general method.

That is, alkylcyclohexanol is used as a substance for introducing phosphorus oxychloride and an alkylcyclohexyl group as a phosphorus source.

However, when applied to the production of a secondary organic phosphate having a sterically bulky group such as an alkylcyclohexyl group, the main component of the reaction product is a primary phosphate, and The secondary phosphate contains only a few percent of the product, which is not suitable as a method for synthesizing alkylcyclohexyl phosphoric acid.

However, a trace amount of the secondary phosphate phosphate contained in the reaction product is dissolved in a solvent (eg, alcohols, ketones) having a high affinity for this, and a crystallization agent such as ethyl acetate is added. When the operation of crystallizing and depositing the secondary phosphate is alternately repeated several times, the purity is considerably improved. However, repetition of such a purification operation causes an increase in cost and cannot be an industrial production method. In addition, the yield is as low as several percent, which further increases the cost.

An object of the present invention is to provide a method capable of producing bis (alkylcyclohexyl) phosphoric acid with high yield and high purity.

[Means and actions for solving the problems]

The present invention relates to phosphorus trichloride as a phosphorus source, alkylcyclohexanol as a substance for introducing an alkylcyclohexyl group, a tertiary amine as a trap for hydrochloric acid generated during the synthesis, and potassium permanganate as an oxidizing agent. The above-mentioned problems have been solved by synthesizing bis (alkylcyclohexyl) phosphoric acid by using them and reacting them under reflux as described below.

In the present invention, the purity can be further improved by dissolving the obtained bis (alkylcyclohexyl) phosphoric acid with a solvent having a high affinity for the bis (alkylcyclohexyl) phosphoric acid and then recrystallizing the solvent with a solvent having a lower affinity.

 Hereinafter, the present invention will be described in more detail.

In order to obtain bis (alkylcyclohexyl) phosphoric acid according to the present invention, phosphorus trichloride is used as a phosphorus source, alkylcyclohexanol is used as a substance for introducing an alkylcyclohexyl group, and tertiary amine is used as a trap for hydrochloric acid generated during the synthesis. (Eg, triethylamine or aromatic amine) and potassium permanganate or the like as an oxidizing agent. Specifically, these are prepared as the following liquid A and liquid B, and first, liquid A is dropped on liquid B,
After that, under a flow of inert gas, the heater is
And heated to reflux.

Solution A: a solution in which a tertiary amine and alkylcyclohexanol are dissolved.

The molar ratio of tertiary amine to alkylcyclohexanol is 2: 3. Solvents to be dissolved are aromatic and aliphatic organic solvents.

Solution B: solution in which phosphorus trichloride is dissolved. Solvent is the same as solution A.

(The molar ratio of the tertiary amine, alkylcyclohexanol and phosphorus trichloride contained in the solution A and the solution B is 2:
3: 1. After the completion of the reaction, washing with water or a mineral acid is performed to remove water-soluble impurities. Thereafter, the organic phase is taken out and the solvent used for dissolution is separated by a distillation method.

Next, an oxidizing agent such as potassium permanganate is added, and a reflux operation is further performed to oxidize the phosphorous acid. The purity at this stage reaches 90%, which is enough to withstand industrial use, but if necessary, it can be obtained by recrystallization with esters (for example, ethyl acetate) to obtain a purity of 99% or more. it can.

 These yields are 90% or more.

Hereinafter, the fact that the method of the present invention is extremely effective will be described in detail based on Reference Examples and Examples.

Reference Example 1 In this reference example, a method using phosphorus oxychloride as a raw material will be described.

0.5 mol / 2/3 volume of phosphorus oxychloride was added to 1 mol / volume of benzene solution of 4 ethyl cyclohexanol, and the mixture was heated to 80 ° C. under a flow of inert gas and reacted under reflux for 65 hours. Was.

After completion of the reaction, 2/3 volume of 0.1N hydrochloric acid aqueous solution was added to carry out hydroxylation, the organic phase was separated, and distilled under reduced pressure at 160-165 ° C / 0.1 mmHg to remove benzene contained in the organic phase. Was performed to obtain a reaction product.

According to mass spectrometry and proton nuclear magnetic resonance analysis of this reaction product, the content of bis (4-ethylcyclohexyl) phosphoric acid as a target substance was 2%, and the main substances of other components were the following primary substances. It was a phosphate ester.

In this reference example, phosphorus oxychloride was added to alcohol, but this reaction was rapid, and there was a possibility that the displacement reaction might be biased. Therefore, if the addition is performed in reverse to make the reaction uniform, an increase in purity can be expected. Also,
Similarly, the addition of a tertiary amine is also expected to be effective in trapping hydrochloric acid which is a by-product of the reaction. This is shown in the following Reference Example 2.

Reference Example 2 1 mol / mol of 0.3 mol / phosphorus oxychloride benzene solution
3/5 volume of a benzene solution containing triethylamine and 1 mol / cyclohexanol was added and reacted in the same manner as in Reference Example 1 to obtain a reaction product. The content of bis (cyclohexyl) phosphoric acid as the target substance in this reaction product was 33%, which was considerably higher than that in Reference Example 1;
It is hard to say that it is still practical.

The method for producing a secondary organic phosphoric acid ester starting from phosphorus oxychloride described in these Reference Examples introduces a relatively linear group such as bis (2-ethylcyclohexyl) phosphoric acid (D2EHPA). It is well known that this is an effective method. However, it can be said that it is a difficult method for efficiently introducing a sterically very bulky group such as bis (alkylcyclohexyl) phosphoric acid which is the object of the present invention.

Next, an example of the present invention using phosphorus trichloride having higher reactivity to introduce a bulky group such as an alkylcyclohexyl group will be described.

Example 1 1 mol per 1 mol of 0.5 mol / phosphorus trichloride benzene solution
l / triethylamine and 1 volume of 1.5 mol / 4 ethylcyclohexanolbenzene solution were added, the mixture was heated to 80 ° C. while flowing nitrogen gas, and reacted under reflux.

After completion of the reaction, 1N sulfuric acid is added to the organic phase in an equal volume, and the mixture is shaken with stirring to remove water-soluble impurities. Then, RC1 (R is 4 ethylcyclohexyl), which is a benzene by-product of the solvent, is removed. Therefore, distillation under reduced pressure was performed at 160 to 165 ° C / 0.1 mmHg.

Next, for hydroxylation, 2 volumes of an acetone solution of potassium permanganate were added, and the mixture was refluxed at 80 ° C. After completion of the hydroxylation, the solvent was distilled off under reduced pressure similarly to remove the solvent. The final product was subjected to mass spectrometry and proton nuclear magnetic resonance analysis to obtain a purity of 92% and a yield of 90%.

As described in Example 1, by using phosphorus trichloride as a starting material, the purity and yield can be remarkably improved, and it is confirmed that the production method is sufficiently practical. did it.

Although the substance according to the present invention has a wide variety of uses, it is particularly useful as an extractant for metal ions, and has a similar structure by introducing a very bulky alkylcyclohexyl group, which is considerably different from the so-called D2EHPA. Extraction behavior can be expected. The purity as a metal ion extractant is usually about 90% and the purity shown in Example 1 is sufficient. However, if necessary for the use as a metal ion extractant or other uses, the following Example By applying the purification method shown in 2, a product with higher purity can be obtained.

Example 2 An equal volume of ethyl acetate was added to a 0.5 mol / benzene solution of the product obtained in Example 1 to crystallize bis (4-ethylcyclohexyl) phosphoric acid, thereby removing impurities.

When the purity was confirmed by the same analytical method as in Example 1, 9
9.5% was obtained. The analysis results are shown in Table 1 and FIG. 1, and the structural formula is shown in FIG. In FIG.
e indicates a resonance absorption line by a corresponding hydrogen atom in the structural formula in FIG. 2, and a numerical value indicates a theoretical integrated intensity ratio. Further, in FIG. 2, a to e represent hydrogen atoms in chemically different states.

Note that what was described in Reference Examples 1 and 2 and Example 1 was 4
-Related to bis (alkylcyclohexyl) phosphoric acid having an ethylcyclohexyl group, but also to those having an alkyl moiety at another position, addition of an alkyl such as a methyl or butyl group, or cyclohexyl without an alkyl moiety It can be manufactured.

[Effects of the Invention] According to the present invention as described above, bis- (4-ethylcyclohexyl) phosphoric acid of high purity and high yield can be produced, and the effect is large.

[Brief description of the drawings]

FIG. 1 is a proton nuclear magnetic resonance spectrum of bis (4-ethylsillohexyl) phosphoric acid. FIG. 2 shows the structural formula of bis (4-ethylsillohexyl) phosphoric acid.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Sadao Senda 245, Miike, Omuta-shi, Fukuoka (58) Field surveyed (Int. Cl. ⁶ , DB name) C07F 9/09 CA (STN)

Claims (2)

(57) [Claims] (1) phosphorus trichloride as a phosphorus source, alkylcyclohexanol as a substance for introducing an alkylcyclohexyl group, a tertiary amine as a trap for hydrochloric acid generated during the synthesis, and potassium permanganate as an oxidizing agent. And reacting them under reflux according to the following to synthesize bis (alkylcyclohexyl) phosphoric acid. 2. The obtained bis (alkylcyclohexyl)
2. The method according to claim 1, wherein the purity is further improved by dissolving the phosphoric acid in a solvent having a high affinity and then recrystallizing the phosphoric acid in a solvent having a lower affinity.