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EP-4293031-B1 - REFINING METHOD FOR PHOSPHORUS COMPOUND

EP4293031B1EP 4293031 B1EP4293031 B1EP 4293031B1EP-4293031-B1

Inventors

  • SAGA YUTA

Dates

Publication Date
20260513
Application Date
20220208

Claims (10)

  1. A method of purifying a phosphorus compound, comprising the steps of: obtaining a mixture of a phosphorus compound represented by the following general formula (1): wherein, in general formula (1), each of R 1 and R 2 independently represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aryloxy group; wherein R 1 and R 2 may be bonded with each other to form a cyclic structure, an alkenyl phosphorus compound represented by the following general formula (2): wherein, in general formula (2), the definitions of R 1 and R 2 are the same as those of R 1 and R 2 in the general formula (1) and a transition metal complex; and subjecting the mixture to distillation after adding a Lewis acid to the mixture, to obtain a first distillate containing the phosphorus compound represented by the general formula (1).
  2. The purification method according to claim 1, wherein the content of a compound represented by the following general formula (3): wherein, in general formula (3), the definitions of R 3 and R 4 are the same as those of R 1 and R 2 in the general formula (1); and R 5 represents a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, or a substituted or unsubstituted allyl group, in the first distillate is 0.1% by mass or less with respect to the total mass of the first distillate.
  3. The purification method according to claim 1 or 2, wherein the Lewis acid is a metal compound and/or a boron compound.
  4. The purification method according to claim 3, wherein the metal compound is at least one selected from the group consisting of a zinc compound, an iron compound and an aluminum compound.
  5. The purification method according to claim 4, wherein the zinc compound is zinc chloride.
  6. The purification method according to any one of claims 1 to 5, wherein each of R 1 and R 2 in the general formulae (1) and (2) independently represents a substituted or unsubstituted alkoxy group having from 1 to 10 carbon atoms, or a substituted or unsubstituted aryl group.
  7. The purification method according to any one of claims 1 to 6, wherein, in the general formula (3), each of R 3 , R 4 and R 5 independently represents a substituted or unsubstituted alkoxy group having from 1 to 10 carbon atoms, a substituted or unsubstituted aryloxy group, or a substituted or unsubstituted allyl group.
  8. The purification method according to any one of claims 1 to 7, wherein the compound represented by the general formula (1) is dimethyl phosphite.
  9. The purification method according to any one of claims 1 to 8, wherein the compound represented by the general formula (2) is dimethyl vinylphosphonate.
  10. The purification method according to claim 2, wherein the compound represented by the general formula (3) is trimethyl phosphite.

Description

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a method of purifying a phosphorus compound. More particularly, the present invention relates to a method of purifying a phosphorus compound by distillation. The present invention also relates to a method of reusing the purified phosphorus compound, as a raw material substance for the synthesis of an alkenyl phosphorus compound. Background Art Organic phosphorus compounds are chemical substances widely used in a variety of products, such as flame retardants, plasticizers, insecticides, pharmaceutical and agricultural chemicals, ligands for metal complexes and the like. In recent years, organic phosphorus compounds are particularly attracting industrial attention as functional materials, also in the fields of constituent materials for metal surface treatment agents, flame retardant resins and the like, and electronic materials. Since phosphonic acid derivatives, among organic phosphorus compounds, are useful precursor substances of a variety of chemical substances described above, various production methods thereof have been conventionally investigated. For example, the production of a phosphonic acid derivative by the addition reaction (hereinafter, referred to as "hydrophosphorylation reaction") of the P(O)-H bond of phosphonic acid to an alkyne, using a catalyst, has been performed. For example, Patent Document 1 proposes a technique of producing a phosphonic acid derivative in which a phosphonic acid diester compound that has been partially hydrolyzed in advance, is used as a raw material. Further, Non-patent Document 1 proposes a technique of producing a phosphonic acid derivative using any of various zero-valent nickel catalysts. Additionally, Patent Document 2 describes a method for producing monoamino-functionalized dialkylphosphinic acids, esters or salts via an alkylphosphonous acid, salt or ester and using catalysts. Citation List Patent Document Patent Document 1: WO 2017/043552Patent Document 2: US 2011/213061 Non-patent Document Non-patent Document 1: J. AM. CHEM. SOC. 2004, 126, 5080 to 5081 SUMMARY OF THE INVENTION Technical Problem In the reaction conditions disclosed in Patent Document 1, however, a mixture containing a raw material phosphorus compound and a product obtained after the hydrophosphorylation reaction is subjected to distillation under reduced pressure, at the time of performing distillation purification, to obtain the raw material phosphorus compound and an alkenyl phosphorus compound. The raw material phosphorus compound obtained at this time can be used again, as a raw material substance for the synthesis of the alkenyl phosphorus compound, to achieve a reduction in the cost of raw materials. However, a new problem has been found out that a side reaction of the raw material phosphorus compound occurs during the distillation purification to generate a by-product that acts as a catalyst poison. In cases where the phosphorus compound containing the thus generated by-product is reused as a raw material substance for the synthesis of the alkenyl phosphorus compound, the yield of the alkenyl phosphorus compound is significantly reduced, and thus, the by-product needs to be removed by purification. This results in a necessity to perform an additional purification process, leading to an increase in the production cost. Solution to Problem As a result of intensive studies to solve the above-mentioned problems, the present inventors have found out that the addition of a Lewis acid to a mixture containing a specific phosphorus compound, a specific alkenyl phosphorus compound and a transition metal complex to distillation enables to reduce the generation of a by-product that acts as a catalyst poison, when subjecting the mixture to distillation, thereby completing the present invention. Specifically, the present invention provides the following inventions. [1] A method of purifying a phosphorus compound, comprising the steps of: obtaining a mixture of a phosphorus compound represented by the following general formula (1): wherein in general formula (1), each of R1 and R2 independently represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aryloxy group; wherein R1 and R2 may be bonded with each other to form a cyclic structure, an alkenyl phosphorus compound represented by the following general formula (2): wherein, in general formula (2), the definitions of R1 and R2 are the same as those of R1 and R2 in the general formula (1) and a transition metal complex; andsubjecting the mixture to distillation after adding a Lewis acid to the mixture, to obtain a first distillate containing the phosphorus compound represented by the general formula (1).[2] The purification method according to [1], wh