DD222596A1 - PROCESS FOR THE PREPARATION OF PURE ALKYL OR ARYLDIESTERS OF PHOSPHORIC ACID - Google Patents

Abstract

Subject of the invention is a preparation of pure alkyl or aryl diesters of phosphorous acid from equimolar mixtures of Phosphorigsaeuremono- and diesters. The aim of the invention is an economical production of pure alkyl or aryl diesters of phosphorous acids from equimolar mixtures of phosphorous mono- and diesters. The object of the invention is the development of a method by which equimolar mixtures of Phosphorigsaeuremono- and diesters, preferably from mixtures of monoesters and diesters of secondary, tertiary or aromatic alcohols, the production of pure alkyl or Aryldiester the phosphorous acid in a technically simple manner is possible. According to the invention, the equimolar mixture of phosphorous mono- and diesters, preferably the mixture of monoester and diester of secondary, tertiary or aromatic alcohols, dissolved in an inert organic solvent, is treated with ammonia gas at 20.degree. C. to 50.degree. The precipitated after treatment NH4 monoester salt of H3PO3 is separated and isolated from the solution of Phosphorigsaeurediester.

Description

Field of application of the invention

The invention relates to a process for the preparation of pure alkyl and aryl diesters of phosphorous acid from equimolar mixtures of Phosphorigsäuremonoestern and Phosphorigsäurediestern. The phosphorous diesters are u.a. can be used as intermediates for the production of crop protection, flame retardants and textile finishing agents.

Characteristic of the known technical solutions

Equimolar mixtures of Phosphorigsäuremonoestern and Phosphorigsäurediestern can be according to DD-PS 87572 by alcoholysis of phosphorus (lll) oxide according to the gross equation

P ₄ O ₆ + 6ROH -> 2HPO (OH) OR + 2HPO (OR) ₂ R = alkyl, aryl

produce. However, a separation of the ester mixtures is not provided.

According to US Patent 3,555,125 the phosphorous acid ester mixtures should be separable by distillation. HEINZ [Pure Appl. former.

44, (1975) 1, on the other hand, describes that phosphorous diesters of secondary and tertiary alcohols are already at 50 ° C. below the

Influence of acidic monoesters to olefins, ethers and phosphorous acid are decomposed. According to DD-PS 108.755 are pure Phosphorigsäuredialkylester, including secondary alcohols, by reaction of gaseous Phosphordll (oxide and a gaseous alcohol in the molar ratio of phosphorus (III) oxide to alcohol from 1 to greater than 8 produced. The disadvantages of this method are that an excess of alcohol must be used, creating an additional Separation operation is required, occurring in vacuum process high technical effort and the additional Energy consumption for the evaporation of alcohols and phosphorus (III) oxide. Furthermore, it is disadvantageous that the Production of diesters of aromatic alcohols is not possible because of the high boiling points of the diesters. Object of the invention

The aim of the invention is a more economical production of pure alkyl or aryl diesters of phosphorous acid from equimolar mixtures of Phosphorigsäuremonoestern and Phosphorigsäurediestern.

The technical problem which is solved by the invention

The invention has for its object to develop a method by which it is possible from equimolar mixtures of Phosphorigsäuremonoestern and Phosphorigsäurediestern, preferably from equimolar mixtures of monoesters and diesters of secondary, tertiary or aromatic alcohols, pure alkyl or Aryldiester the phosphorous acid In technically easy to produce.

Feature of the invention

A process has been found for preparing pure alkyl or aryl diesters of phosphorous acid from equimolar mixtures of phosphorous monoesters and phosphorous diesters.

This process is characterized in that the equimolar mixture of phosphorous acid monoesters and phosphorous diesters, preferably the equimolar mixture of monoesters and diesters of secondary, tertiary or aromatic alcohols, dissolved in an organic solvent inert to the ester mixture, preferably chloroform, benzene, 1,4- Oioxan, treated with ammonia gas at a temperature between 20 ° and 5O ⁰ C, the precipitated after the treatment ammonium monoester salt of the phosphorous acid and isolated from the solution of the phosphorous diesters in a conventional manner. The precipitation of the monoester salt is complete when no more heat is generated and the solution is neutral. The ammonium monoalkyl or monoaryl phosphites precipitate quitatively as white, voluminous precipitates and can be filtered off well from the reaction solutions containing the diesters. After washing with ether and drying, z. B. over phosphorus pentoxide, the ester salts are present as fine, powdery, white solids. After the monoesters have been separated off as ammonium salts, the diesters are recovered from the filtrate in pure form by vacuum distillation at bottom temperatures below 200 ° C. The decomposition reactions described by HEINZ do not occur in the process according to the invention.

In the normal state solid diester after separation of the monoester salts and optionally the solvent not by way of distillation, but advantageously by recrystallization, z. B. from ether, purified. 31P-NMR and wet-chemical investigations showed that the ammonium ester salts and diesters of secondary, tertiary and aromatic alcohols prepared by the process according to the invention are present in very pure form.

Ausführungsbeispieie

The method according to the invention is explained in more detail by the following exemplary embodiments, but the invention is not limited to these examples.

example 1

In a reaction vessel equipped with stirrer, dropping funnel and thermometer, at an initial temperature of 20 ⁰ C to a solution of 37.3 g (0.62 mol) of isopropanol in 10 ml of chloroform with vigorous stirring within 45min 22.0g (0.1 mol ) Phosphorus (III) oxide is added dropwise. The temperature increases during the reaction to 70 ⁰ C and decreases during the stirring (30 minutes) back to room temperature. Ammonia is introduced into the solution with vigorous stirring and cooling (T <30X) until no further evolution of heat occurs after about 20-30 minutes.

-2- 258 090

After filtering off the ammonium monoisopropyl phosphite and stripping off the chloroform, 32.1 g of phosphorus acid red isopropyl phosphate are obtained in the subsequent vacuum distillation

Phosphorous acid dHsopropyl & ter K ,, * """" = 37 ⁰ C

n ^ O = 1/4083

Ammoniurrimonoisopropyl phosphite F _p = 127-30 ° C

Example 2

In a reaction vessel equipped with stirrer, dropping funnel and thermometer, 46.9 g (0.62 mol) of tert. Butanol while stirring and cooling within 70 minutes continuously 22.0g (0.1 mol) of phosphorus (lll) oxide added dropwise. The temperature is kept below 30 ° C. by cooling and the reaction solution is stirred at room temperature for 30 minutes, then the reaction solution is diluted with 50 ml of benzene and ammonia is introduced into the solution with vigorous stirring and cooling (T <30 ^° C.) If the solution is neutral and the solution is neutral, the precipitated ammonium tert-butyl phosphite is filtered off with suction, the benzene is stripped off and the phosphorous acid di-tert-butyl ester is distilled under reduced pressure in an oil pump. (Yield: 38.2 g) Phosphoric acid di-tert-butylflster K *>^3t>'= 57X

nfr = 1.4183

Ammonium-tert-butyl phosphite F _p = 150-53 ⁰ C

Example 3

Irr a reaction vessel equipped with stirrer, dropping funnel and thermometer, to a solution of 56, Bg (0.6 mol) of phenol in 30ml benzene with stirring and cooling within 30 minutes 22.0g (0.1 mol) of phosphorus (lll ) -oxld dripped. The temperature of the Reaktionslösunfl is kept by cooling under toilet. After the dropwise addition of the phosphorus (III) oxide, stirring is continued for a further 30 minutes at room temperature. Subsequently, the reaction solution is saturated with strong stirring and cooling (T <40 ° C) with ammonia. After about 60 minutes, when no more heat development occurs and the solution is neutral, the precipitated Ammoniummonophenylphosphit is filtered off, the benzene is removed and distilled the Phosphortgsäure-diphenyl ester in vacuo. (Yield: 43.1 g) Phosphorous acid di-phenyl ester K "* = 143-5 ° C

ng ⁰ = 1.5567

Ammonium monophenyl phosphite F "= 175-7 ⁰ C

Claims (1)

-ι- 258 090 2 Invention claim: Process for the preparation of pure alkyl or aryl diesters of phosphorous acid from equimolar mixtures of phosphorous acid monoesters and phosphorous diesters, characterized in that the equimolar mixture of phosphorous acid monoesters and phosphorous diesters, preferably the equimolar mixture of monoesters and diesters of secondary, tertiary or aromatic alcohols dissolved in one compared with the ester mixture inert organic solvent, preferably chloroform, benzene, 1,4-dioxane, treated with ammonia gas at a temperature between 20 ° and 50 ⁰ C, which separates after treatment precipitated Ammoniunmonoestersalz the phosphorous acid and from the solution of Phosphorigsäurediester in isolated in a known manner.