JPH11236365A - Production of trifluoromethanesulfonic acid anhydride - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject acid anhydride useful as a raw material of a medical agent, an agricultural agent, etc., or a catalyst at a high selectivity and a high yield by reacting trifluoromethanesulfonic acid with phosphorus pentoxide instead of diphosphorus pentoxide. SOLUTION: (C) Trifluoromethanesulfonic acid anhydride (CF3 SO2 )2 O} is obtained by reacting (A) trifluoromethanesulfonic acid (CF3 SO3 H) with (B) phosphorus pentoxide (PCl5 ). Preferably, an adding amount of the component B is 0.2-0.6 mol based on 1 mol of the component A. Preferably, the temperature at adding of the component B is <=40 deg.C and the reaction temperature is 20-80 deg.C. By the process, a coagulation of the reaction solution with a by-product generated in a case of using diphosphorus pentoxide is diminished and the reaction can be continued, and the product can readily be separated and purified by distilling after the finish of the reaction because all of the unreacted raw materials and the reaction products are liquids.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing trifluoromethanesulfonic anhydride. Trifluoromethanesulfonic anhydride is used in pharmaceuticals, pesticides,
It is a compound that is useful as a raw material, catalyst, or the like when producing various functional materials.

[0002]

Conventionally, as a method for producing trifluoromethanesulfonic anhydride, trifluoromethanesulfonic acid is reacted with diphosphorus pentoxide and dehydrated and condensed as shown in the following reaction formula. Thus, a manufacturing method is known.

[0003]

Embedded image 6CF ₃ SO ₃ H + P ₂ O ₅ → 3 (CF ₃ SO ₂ ) ₂
O + 2H ₃ PO _4, however, in this manufacturing method, glassy polyphosphates ends up consolidating the reaction by-produced, it becomes impossible to stir the reaction liquid, that it becomes impossible to continue further reaction There is also a problem that it is difficult to treat the by-produced polyphosphoric acid after the completion of the reaction, so that it is not suitable as a method for industrially producing trifluoromethanesulfonic anhydride.

[0004]

The inventors of the present invention have conducted intensive studies with the aim of solving the above-mentioned problems. As a result, trifluoromethanesulfonic acid was replaced with phosphorus pentachloride instead of diphosphorus pentoxide. The present inventors have found that trifluoromethanesulfonic anhydride can be easily produced with high selectivity and high yield by reacting with, and arrived at the present invention.

That is, according to the present invention, trifluoromethanesulfonic acid [CF ₃ SO ₃ H] is converted to phosphorus pentachloride [PCl ₅ ].
And trifluoromethanesulfonic anhydride [(CF ₃ SO ₂ ) ₂ O].

Hereinafter, the method for producing trifluoromethanesulfonic anhydride of the present invention will be described in detail. In the method for producing trifluoromethanesulfonic anhydride of the present invention, trifluoromethanesulfonic acid [CF ₃ SO ₃
H] is reacted with phosphorus pentachloride [PCl ₅ ] to produce trifluoromethanesulfonic anhydride [(CF ₃ SO ₂ ) ₂ O] according to the following reaction formula.

[0007]

Embedded image 2CF ₃ SO ₃ H + PCl ₅ → (CF ₃ SO ₂ ) ₂ O
+ POCl ₃ + 2HCl In the present invention, the amount of phosphorus pentachloride to be added is preferably 1 mol or less, more preferably 0.2 mol to 0.6 mol, per 1 mol of trifluoromethanesulfonic acid. When the molar ratio of phosphorus pentachloride to trifluoromethanesulfonic acid is increased, trifluoromethanesulfonyl chloride [CF ₃ SO ₂
Cl] is increased, which is not preferable because it causes a decrease in the yield of trifluoromethanesulfonic anhydride, which is the target product. When the molar ratio of phosphorus pentachloride to trifluoromethanesulfonic acid exceeds 0.6,
Since the yield of the target product, trifluoromethanesulfonic anhydride, is 50% or less, in order to perform the reaction more efficiently, the molar ratio of phosphorus pentachloride to trifluoromethanesulfonic acid is 0.6 or less. You had better. On the other hand, when the molar ratio of phosphorus pentachloride to trifluoromethanesulfonic acid is small, the by-product of trifluoromethanesulfonyl chloride can be suppressed. However,
In the present invention, the amount of trifluoromethanesulfonic anhydride, which is the target product, depends on the amount of phosphorus pentachloride added. Therefore, when the molar ratio of phosphorus pentachloride to trifluoromethanesulfonic acid is reduced, the yield per reaction decreases accordingly, and the productivity of trifluoromethanesulfonic anhydride, which is the target product, decreases. Therefore, it is not preferable. When the molar ratio of phosphorus pentachloride to trifluoromethanesulfonic acid is reduced to about 0.2, the by-product of trifluoromethanesulfonyl chloride can be almost completely suppressed.
It is better to be 0.2 or more.

[0008] Since the addition of phosphorus pentachloride generates heat, the temperature at the time of addition is preferably 40 ° C or less,
It is more preferably under ice cooling to 20 ° C. Further, the reaction temperature is not particularly limited, but is preferably 20 ° C to 80 ° C. In order to allow the reaction to proceed more efficiently, it is preferable to slightly warm the reaction, and the more preferable reaction temperature is 40 ° C.
70 ° C.

In the present invention, trifluoromethanesulfonic anhydride and phosphoryl chloride [P
OCl ₃ ] is produced. Further, trifluoromethanesulfonyl chloride may be produced as a by-product, but these are all liquids at room temperature, including trifluoromethanesulfonic acid, which is an unreacted raw material. As in the case, the reaction solution does not solidify. Further, since all of the unreacted raw materials and products are liquid at room temperature, they can be easily separated and purified by distillation after the completion of the reaction. Therefore, in the present invention, the target product, trifluoromethanesulfonic anhydride, can be obtained very easily and efficiently, so that operability and productivity are very high as compared with conventional production methods. It has the advantage of being better.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be specifically described below with reference to examples.

[0011]

Example 1 To 45.02 g (0.3 mol) of trifluoromethanesulfonic acid, 31.24 g (0.15 mol) of phosphorus pentachloride was successively added. After the addition, the mixture was heated and stirred at 70 ° C. for 5 hours. After completion of the reaction, distillation was performed to obtain 22.71 g (53.7%: yield based on phosphorus pentachloride) of trifluoromethanesulfonic anhydride.

Boiling point: 81 ° -83 ° C. Example 2 Under ice cooling, 22.51 g of trifluoromethanesulfonic acid
(0.15 mol) to 7.81 g (0.038 g) of phosphorus pentachloride
Mol) were added sequentially. After the addition, warm and add
Stirred for hours. After completion of the reaction, distillation was performed to obtain 9.00 g (84.0%: yield based on phosphorus pentachloride) of trifluoromethanesulfonic anhydride.

Boiling point: 81 ° C. to 83 ° C.

[0014]

According to the production method of the present invention, trifluoromethanesulfonic anhydride, which is a compound useful as a raw material or a catalyst for producing pharmaceuticals, agricultural chemicals, various functional materials, and the like, can be easily obtained with high selectivity and high selectivity. Can be produced in yield.

Claims (2)

[Claims] (1) Trifluoromethanesulfonic acid [CF ₃ S
O ₃ H] is reacted with phosphorus pentachloride [PCl ₅ ] to obtain trifluoromethanesulfonic anhydride [(CF
₃ SO ₂ ) ₂ O]. 2. The process for producing trifluoromethanesulfonic anhydride according to claim 1, wherein the amount of phosphorus pentachloride is from 0.2 mol to 0.6 mol per 1 mol of trifluoromethanesulfonic acid. Method.