DD301664A7 - METHOD FOR THE PREPARATION OF CYANIDES OF TETRAKOORDINATED PHOSPHORUS - Google Patents

Abstract

The invention relates to a process for the preparation of cyanides of the tetracoordinate phosphorus of the general formula R exp 1 (R exp 2) P (Y) CN. Such compounds are potential biocides. The object of the invention is to enable a new economically favorable synthesis of a wide range of the title compound under mild conditions. The compounds can be prepared by direct conversion of trivalent phosphorus compounds R exp 1 (R exp 2) (R exp 3 Y) P with ammonium cyanide NH ind 4 CN and a polyhalocarbon compound C in m H ind n X ind k R.

Description

Field of application of the invention

The invention relates to a process for the preparation of cyanides of tetracoordinated phosphorus of the general formula

f ii * "'γ

R ', R ² = any organic radicals, eg. B. alkyl, aryl, alkoxy, alkylthio, aroxy groups, ring systems, dialkylamide, diarylamide

and / or Alkylarylamidgruppen and Y = O may be ₁ S.

Such compounds are used in the field of biology, agriculture and forestry and in industry as biocides (insecticides, acaricides, nematicides) and as synthetic building blocks in organophosphorus chemistry application.

Characterization of the known technical solutions

The following methods are known for the preparation of cyanides of tetracoordinate phosphorus:

1. Implementation of phcsphororganischen chlorides of phosphoric, phosphonic or phosphinic acid with ionic cyanides (G. SCHRADER, unpublished work, see HOUBEN / WEYL, Vol 12/2, p 299, Georg Thieme Verlag Stuttgart).

2. Reaction of trialkyl phosphite with cyanogen halides (B.C. SAUNDERS, Ber., Formerly Ges. Belgrade 23/24 [1958/19591, 424, Chom. Zentralblatt 1962, 1530).

The disadvantages of the above-mentioned processes are, above all, the use of P-Cl compounds, whose synthesis can be carried out only via the intermediate stage of the expensive phosphorus halides and not directly from elemental phosphorus. The synthesis of the volatile and highly toxic halogen cyanides also requires the use of elemental halogen (method according to point 2). The ionic cyanides used are generally poorly soluble in the reaction media used and thus lead to heterogeneity of the reaction, which among other things, intensive stirring, long reaction times, higher temperatures and yield reductions result.

Object of the invention

The aim of the invention is to enable a new, economically favorable synthesis of a wide range of title compound under mild conditions in high yields.

Explanation of the essence of the invention

The object of the invention is to obtain the title compound in one process step while improving the economic parameters and with great reliability. As organophosphorus starting materials are primarily compounds are used, which are accessible in one step from elemental phosphorus.

It has been found that cyanides of tetracoordinated phosphorus of the general formula

,1

R ¹ , R ² = any organic radicals, eg. B. alkyl, aryl, alkoxy, alkylthio, Aroxygruppen, ring systems, Dialkylamid-, Diarylamid-

and / or alkylarylamide groups and Y = O, S

may be, by direct reaction of trivalent phosphorus compounds R ¹ IR ² I (R ¹ Y), wherein R 'and R ^{2 may be} the above and R ³ = alkyl groups, with ammonium cyanide NH ₄ CN and a polyhalocarbon C _m H "X _k R, where X = halogen and R = any organic radical, halogen or hydrogen can be obtained with or without solvent at a reaction temperature between zero and 8O ⁰ C.

In addition to the title compound, two halohydrocarbon compounds and ammonia are formed, which can be easily removed from the reaction mixture. The general reaction equation is:

The method according to the invention has the following decisive advantages:

1. The reaction takes place in one process step under mild conditions in high yields.

2. The organophosphorus starting materials are largely accessible to LEHMANN (DD-WP 127187 and DD-WP 127188) directly from elemental phosphorus.

3. The method is applicable to a wide range of compounds.

4. The synthesized title compound can be easily rid of the other, usually highly volatile reaction products.

5. Since ammonium cyanide is readily soluble in organic solvents, the reaction takes place in a homogeneous phase, which has an advantageous effect on reaction time and yield.

Autführungsbeisplelo

The preparation of the target compound is carried out according to the following general instructions: A mixture in the molar ratio R '(R ^J ) (R ³ Y) P: NH 4 CN: C _m H _n X _k R = 1: 21: 1

is reacted with exclusion of moisture (Inertgasatmosphära) and constant stirring. The reaction can be carried out without a solvent, but better in an inert dipolar aprotic solvent. The optimum reaction temperature depends on the particular reactants. After 1-2 hours, the reaction is usually completed. After separation of the volatiles including the solvent, the reaction product may optionally be a fine cleaning, for. B. be subjected to vacuum distillation.

1. Preparation of Cyanophosphonsäurediethylester

With exclusion of moisture, 0.06 mol of triethyl phosphite (EtO) ₃ P and 0.065 mol of ammonium cyanide are dissolved in 10 ml of dry acetonitrile. Then 0.06 mol CCI _{4 are} added at a reaction temperature of 35-40 ° C with occasional stirring. After 1-1 VJ hours, the reaction is in progress. The resulting CHCl ₃ , EtCl, NH ₃ and the solvent are removed on a rotary evaporator. Eventually precipitated EtNH ₃ CI is filtered off. From the ^{> 1} P NMR spectrum it follows that the target product has formed to 85%.

2. Preparation of Cyanophosphonsfiuredibutylester

With exclusion of moisture, 0.03 mol of tri-n-butyl phosphite (BuO) ₃ P is mixed with 0.035 mol of ammonium cyanide without solvent. Then, at a reaction temperature of 40 ° C and with constant stirring, the addition of 0.03mol CCI ₄ follows. After 1 'Λ hours of precipitated BuNH ₁ Cl freed and residual CHCl ₃ , BuCl and NH _{3 are} removed on a rotary evaporator. The yield of the target product is 80%.

Claims (2)

1. A process for the preparation of cyanides of tetracoordinated phosphorus of the general formula ^ ί - '- R ¹ , R ² = any organic radicals, 2. B. alkyl, aryl, alkoxy, alkylthio, aroxy groups, Ring systems, dialkylamide, diarylamide and / or alkylarylamide groups and Y = O, S in a process step trivalent phosphorus compounds R ¹ IR ² X ³ Y) P, where R ¹ and R ^{2 may be} the above and R ³ = alkyl groups, ammonium cyanide NH ₄ CN and a polyhalocarbon Cr _n H _n X) ₁ R, where X = halogen and R = any organic radical, halogen or hydrogen may be reacted with or without solvent at temperatures between zero and 80 ^c C. 2. The method according to item 1, characterized in that when using a solvent predominantly a dipolar aprotic, z. For example, acetonitrile, is used.