FR2626884A1 - PROCESS FOR THE PREPARATION OF N-PHOSPHONOMETHYL-IMINO-DIACETIC AND ACID CHLORIDE THEREFROM - Google Patents

Abstract

Process for the simultaneous preparation of N-phosphonomethyl-imino-diacetic acid and lower acid chloride using imino-diacetic acid and phosphorus trichloride, which process consists of reacting phosphorus trichloride and carboxylic acid in C1 -C4 in a molar ratio of about 1/3 at a temperature between 0 and 20 degree (s) C, to separate the phosphoric acid phase formed from the chloride phase of carboxylic acid and to isolate the acid chloride carboxylic acid, then after dilution in water, reacting the phosphorous acid phase also containing the carboxylic acid and the carboxylic acid chloride with the imino-diacetic acid and the aqueous formaldehyde solution, the imino acid molar ratio -diacetic / phosphorous acid / formaldehyde being of the order of 1/1 to 1.1 / 1 to 1.2, in the presence of a strong mineral acid, preferably hydrochloric acid, which is added to a temperature between 60 and 120 degree (s) C, then to evaporate the mixture ju until the crystals separate.

Description

PROCESS FOR THE PREPARATION OF N-PHEOSPHONOMETYL-MINO-DIACETIC

  AND ACID CHLORIDE THROUGHOUT -

  The subject of the present invention is a new process for the simultaneous preparation of N-phosphonomethyl-imino-dliacetic acid.

  and lower carboxylic acid chloride. -

  N-phosphononmxthyl-imino-diacetic acid is an inter-

  important medium in the preparation of herbicides of the glyphosate type having a broad spectrum of activity. Similarly, the carboxylic acid chlorides derived therefrom are also important and are often used as reagents in syntheses in organic chemistry:

  Simultaneous economic preparation of the two products.

  has not been described in the literature so far.

  A method of preparing N-phosphono.mthyl- acid.

  imino-diacetic is described in British Patent No. 2,154,589; according to this patent, an aqueous solution of a sodium salt of iminodiacetic acid is treated with the acid

  hydrochloric all from ababora, then with an aqueous solution of-

  phosphorus and formaldehyde trichloride.

  Depending on the reaction, hydrochloric acid is first added

  In the aqueous solution of the sodium salt of imino-diacid acid-

  tick and part of the tc = me water are separated by istillation.

  The phosphorus trichloride is then added to 10O-1120C. The reaction mixture obtained contains the hydrochloride of imino-diacetic acid, sodium chloride, water and phosphorous acid. An aqueous formaldehyde solution is then

  added to the reaction mixture at a. temperature around -

  108-1100C and the reaction is allowed to continue at this temperature for at least 90 minutes. At the end of the reaction,

  sodium hydroxide is added to the reaction mixture,.

  separates it by filtration and the filter cake is washed several times with water, then dried. The yield obtained is around 87% 9%. The downside of this

  process is that, due to the presence of water, chlorhy-

  drique which forms in addition to phosphorous acid from

  phosphorous trichloride cannot be used and only its destruction

  tion requires high costs. In addition, it strongly contaminates the environment. Sodium chloride formed in parallel cannot also be used; it pollutes the final product and can only be removed from this final product after several washes. In GB-PS 2 021 589, the phosphorus trichloride and the water react, all at once, & 400C, which allows the preparation of N-phosphonomethyl-iminodiacetic acid, then imino-diacetic acid is added to the solution & the

  boiling point then the aqueous formal-

  dehyde and 2/3 of the water formed are separated by distillation.

  N-phosphonomethyl-imino-diacetic acid precipitates from

  solution after addition of ethanol and the above crystals

  pites are washed with ethanol and water. The disadvantage of this process is, among other things, that most of the 3 molecules of hydrochloric acid formed per mole and which are used for the decomposition of phosphorus trichloride, can only be used in the process because 1 / 3 of the hydrochloric acid formed is sufficient for the implementation of the phosphonomethylation process. The destruction of hydrochloric acid disadvantageously influences,

  the economy of the process and causes pollution of the environment

  is lying. Other known processes are based on the similar principle and their main characteristics are that the chlorine atoms of phosphorus trichloride are used

  for the formation of hydrochloric acid or which are trans-

  formed in sodium chloride, the elimination of the two influen-

  : disadvantageously erasing the economics of the process and the

product quality.

3 -

  The subject of the present invention is the combined use

  full of chlorine atoms of phosphorus trichloride used

  for the preparation of N-phosphonomthyl-imino-diac- acid

  tick. Another object of the invention is the elimination of environmental pollution and the destruction of deleterious secondary products such as hydrochloric acid and sodium chloride as well as avoiding their formation The process according to the present invention , for the simultaneous preparation of N-phosphonomnthylununo-diacetic acid and -lower carboxylic acid chloride by deriving, by

  use of imino-diacetic acid and phosphorous trichloride.

  is characterized by the reaction of phosphorus trichloride and a C1-C4 carboxylic acid used.

  approximately 1/3 molar, and by the separation of phos-

  phorous formed and carboxylic acid chloride one of

  the other, then the separation of the carboxylic acid chloride.

  After dilution in water, the phosphorous acid phase also containing carboxytic acid and the carboxylic acid chlorutre reacts with imino-diacetic acid and the aqueous formaldehyde solution at a temperature between 60 and 1200C in the presence of an added mineral acid,

  preferably in the presence of hydrochloric acid, then is eva-

  porous until separation of the crystalline product,

  The imn-diacet acid / que / phos acid- molar ratio

  phorous and formaldehyde is in the range of 1/1 to 1.1 / 1 & 1.2. Phosphorous trichloride and carboxylic acid,

  preferably 1 acetic acid, react at 0-20 C ,.

  Optionally, the carboxylic acid and chloride content

  of carboxylic acid and, in particular, the content of chlorhy-

  dric of the phosphorous acid phase formed by reaction of phosphorous trichloride and carboxylic acid can

  be reduced by distillation. To promote the precipita-

  tion of the 1-phosphonomthyl-imino-diacetic acid obtained at the end of the synthesis, the reaction mixture is evaporated to approximately

2/3 of its volume.

  In order to obtain the advantages of the invention, it is not absolutely necessary to remove the individual constituents from the reaction mixture obtained after reaction of the phosphorus trichloride and the carboxylic acid, likewise the precipitation of the constituents having no not reacted or starting materials, is also not of great importance. Phosphorous acid, carboxylic acid chloride and carboxylic acid can be separated by simple sedimentation of the phases, by

  distillation or by extraction of the phosphorous acid phase.

  The carboxylic acid can react in the given molar ratio, at a temperature between -10 and 1000C, from

  preferably at a temperature between 0 and 200C, depending.

  the following reaction scheme: PC13 + 3 R-COOR i> H3PO3 + RCOC1

  In addition to cooling and agitation, it is preferred

  maple to add phosphorous trichloride to carboxy-

  However, this process can be implemented by addi-

  tion of substances in a reverse sequence. After reaction, the phosphorous acid and the hydrochloric acid formed are present in two distinct phases and separate from each other. The upper hydrochloric acid phase is separated "for later use. The lower phosphorous acid phase generally contains 80% to 98% phosphoric acid, 2% to 0% carboxylic acid and 1% to 5% chloride. carboxylic acid The lower phase obtained from the reaction mixture can be reacted directly with the aqueous formaldehyde solution at the given temperature. In fact, the process is carried out by adding the solution

  aqueous formaldehyde to the mixture containing phospho- acid

  reux, imino-diacetic acid and aqueous hydrochloric acid solution at the boiling temperature of the mixture. After evaporation, the final product precipitates and can be separated by filtration. The advantages of the process can be summarized as follows: - when the phosphorus trichloride and the carboxylic acid are reacted in the suitable molar ratio, the phosphorous acid suitable for the preparation of acid

  N-phosphonomethyl-imino-diacetic and acid chloride

  - carboxylates capable of being used separately are formed simultaneously; - the chlorine atoms of phosphorous trichloride can be completely used and the destruction of the annoying excess hydrochloric acid is not necessary: - part of the investment required to fight against environmental pollution can be saved and the secondary product (NaCI) formed is neutralized; thus the environment is not seen to be contaminated; - the main reaction mixture does not contain sodium chloride, so that the impurities which constitute the inclusions of sodium chloride in the final product can be removed; - the process can be implemented in a device

classic chemical.

  Other objects and advantages of the present invention will appear on reading the description and examples.

given without limitation.

EXEHPLE I

  g (3 moles) of acetic acid are poured into a

  four-necked container, capable of being heated or re-

  cooled and equipped with an agitator, a thermometer and a reflux condenser. 137.3 g (1.0 mol) of phosphorous trichloride at a temperature below 40 ° C. are introduced into this flask & bromine into this flask. The reaction mixture is then = heated to 40-50 ° C. and stirred at this temperature.

for 30 minutes.

  The mixture obtained is then kept at rest and the phases are allowed to separate simultaneously. The upper phase containing acetyl chloride is separated and can be used for technical purposes, the lower phase corresponding to approximately 96 g and containing phosphorous acid and containing, in addition, 6% by weight of hydrochloric acid, 2%. '

  by weight of acetyl chloride and 10% by weight of acetyl acid

  that, is mixed with 30 cm1 'of water and then poured into an ampoule

to bromine.

  In the aforementioned container, 119.7 g (0.9 mole of iminodiacetic acid, 130 cm3 of water and 48 g of hydrochloric acid & 37% by weight) are added, then the lower phase obtained in the aforementioned step and containing phosphorous acid is added to the mass which is stirred from the dropping funnel. The mixture thus obtained is heated to boiling point and 97 g (1.1 moles) of an aqueous solution at 34 % formaldehyde is added to it, the reaction mixture is brought to reflux temperature for several hours, then 2/3 of its volume is separated by distillation, it is then cooled to 10 ° C. and the crystals obtained are filtered off. they are dried with cold water to obtain 173 g of acid

  N-phosphonomethyl-imino-diacetic having a point of lbul-

-10 lition of 208-209 "C.

  * The yield is 84.6%, calculated from imino-diacetic acid.

EXAMPLE 2

  The process according to Example 1 is followed, with the difference that the phosphorus trichloride, hydrochloric acid, acetic acid and acetyl chloride present in the lower phase obtained by reaction of phosphorus trichloride and

  acetic acid is distilled. The amount of hydrochloric acid

  only 37% introduced. is increased to 74.7 g. The phosphorous acid phase thus obtained, containing 2% hydrochloric acid, 1% acetyl chloride and 4% acetic acid, then undergoes

  further processing as described in Example 1.

  13.1 g of N-phosphonomethylimino- acid are thus obtained.

  diacetic pr'sehtant a boiling point of 209 g. The

  yield is equal to 84.7% of the theoretical yield.

EXAMPLE 3

  The process is carried out as described in Example 1, with the difference that the content of acetic acid and acetyl chloride in the phosphorous acid phase obtained during the reaction of phosphorus trichloride and acetic acid is reduced by addition of phosphorus trichloride and by successive precipitation. The phosphorous acid phase thus obtained containing 7% acetic acid, 1.5% acetyl chloride and 4% hydrochloric acid is added to the mixture.

  formed from 152.5 g (0.9 mole) imino acid hydrochloride

  diacetic and in 150 ml of water. The mixture obtained is heated to the boiling temperature and 97 g (1.1 moles) of a 34% aqueous formaldehyde solution are added over one hour. We

26268S4

  then brings to the boiling point under reflux during

  two additional hours, then evaporates to 2/3 of its volume.

  It then forms by crystallization of the crystals of the acid

  N-phosphonom6thyl-inino-diacetic.

  À 176 g of a product are thus obtained, the boiling point of which is 209-210aC, which represents 86.2% of the theoretical yield. -10 a

Claims (3)

  1.- Process for the simultaneous preparation of N-phospho- acid   nomethylimino-diacetic acid and lower acid chloride   use of imino-diacetic acid and phos trichloride   phore, a process which consists in reacting the phosphorus trichloride and the C 1 -C 4 carboxylic acid used in a molar ratio of approximately 1/3, at a temperature between 0 and "C, to separate the phosphoric acid phase formed of the carboxylic acid chloride phase and isolating the carboxylic acid chloride, then after dilution in water, reacting the phosphorous acid phase also containing the carboxylic acid and the carboxylic acid chloride with l iminodiacetic acid and the aqueous formaldehyde solution,   acid molar ratio. imino-diacetic / phosphorous acid / form-   maldehyde being of the order of 1/1 to, 1/1 to 1.2, in the presence of a strong mineral acid, preferably consisting of hydrochloric acid, which is added at a temperature between 60 and 120 C, then evaporate the mixture until the crystals separate.   2.- A method according to claim 1, which consists   use acetic acid as the carboxylic acid.   3. A method according to claim 1, which consists in   reduce the amount of carboxylic acid and a- chloride   carboxylic acid as well as respective hydrochloric acid-   ment-present in the phosphorous acid phase obtained during   the reaction of phosphorous trichloride and carboxy acid   lique, by distillation or by treatment with trichloride   phosphorous prior to reaction with formaldehyde.