DD273636A5 - PROCESS FOR THE PREPARATION OF PHOSPHANES - Google Patents

Abstract

The invention relates to a process for the preparation of phosphines. For the preparation of phosphanes of the general formulas RnPH3n (I) H2P (CH2) mPH2 (II) or (C6H5) 2PCH2PH2 (III) wherein the substituents have the description given in the description, phosphine is reacted with the corresponding chloro- or bromo-hydrocarbons in the presence of a Alkalihydroxidloesung and implemented by dimethyl sulfoxide.

Description

For this 2 pages tables

Field of application of the invention

The present invention relates to the preparation of phosphanes of the general formulas

R _n PH _3. ,, (D.

H ₂ P- (CH ₂ L-PH ₂ (M) or

(C ₆ Hs) ₂ P-CH ₂ -PH ₂ (III)

in which R is a straight-chain or branched alkyl group having 1 to 24C atoms or a cycloalkyl, benzyl or allyl group, m is 2,3 or 4 and η is 1 or 2, which are used in the chemical industry.

Characteristic of the known state of the art

Alkylphosphanes are gaining increasing technical importance as building blocks for the preparation of higher organophosphorus compounds. So far there has been no lack of attempts to obtain these phosphines, with very different

Paths were taken.

So is u. a. also already the reaction of phosphine (PHj) with methyl iodide in the presence of KOH and dimethyl sulfoxide

(DMSO) (William L. Jolly, Inorganic Synthesis, Vol. 11 (1968) pp. 124 and 126).

A disadvantage of this procedure, however, is that it is suitable only for work on a laboratory scale in small quantities and the methyl iodide used is very expensive, toxic and carcinogenic. In addition, it is necessary to solidify KOH in finely ground

Form, suspended in DMSO, use.

It is also known to react phenyl and diphenylphosphines in the presence of dimethyl sulfoxide (DMSO) and aqueous concentrated KOH with the aid of alkyl halides to give the corresponding secondary and tertiary phosphines (Synthesis 1986,

Pages 8 to 22).

A disadvantage of this method is that this route leads only to secondary and tertiary phosphanone, which inevitably

at least one phenyl group as a substituent.

Object of the invention

The invention provides a new process for the preparation of phosphines. With this method, the disadvantages of the previously known methods are overcome.

Explanation of the essence of the invention

The object of the invention is to provide an improved process for the preparation of phosphines. With the method according to the invention phosphanes of the above-mentioned general formulas I to III are prepared from readily available phosphine (PH ₃ ) as the starting material, if phosphine in the presence of both an SO to 70Gew .-% aqueous alkali hydroxide solution and of dimethyl sulfoxide with reagents of the general formula RX, X (CH ₂ ) _m X or (C ₆ Hf ₁ I ₂ P-CH ₂ -X in which R and m have the meanings indicated and X is chlorine or bromine, at temperatures between 0 and 70 ° C and an overpressure of 0 to 10bar, wherein in each case at least 1 mole of alkali metal hydroxide per mole of X used.

Advantageous embodiments of this method are z. B., that the reaction at temperatures of 0 to 50 ° C and at pressures between 0.1 and 8 bar is performed.

embodiments

The following tables list as examples products obtained by reacting phosphine with various reagents.

For the reaction of the halogen compounds which are liquid under normal conditions, the following simple procedure can be used (Method A, Examples 1 to 6):

Method A (Examples 1-6):

In a stirred apparatus (3-necked flask equipped with stirrer, dropping funnel, reflux condenser) was suspended with vigorous stirring 56% aqueous KOH solution in DMSO. By purging with nitrogen, the reaction system was freed of oxygen.

Thereafter, PH _{3 was introduced} at an overpressure of about 100 mbar to saturation. In this solution, the respective reagent was added dropwise. The onset of the reaction was easily detected by the rapid absorption, by post-dosing the PH ₃ overpressure was kept constant. No-reaction of PH ₃ was not observed. After completion of the reaction, the reaction was treated at 0 ° C (1: 1) ml of degassed water, with phase separation occurring. To better separate the resulting phosphines, n-pentane was extracted. The extract was washed with water and over sodium sulfate

dried. The solvent was distilled off at normal pressure and the residue was fractionated.

The physical data of the reaction products obtained corresponded in all cases from the literature for these

Connections of known values.

The reaction of alkyl halides which are gaseous at normal temperature and pressure is advantageously carried out by method B

carried out:

Method B (Examples 7 and 8)

In a 5-liter laboratory autoclave were successively condensed at about -4O ⁰ C dia desired amounts of alkyl halide and PH ₃ . After heating to the cooling water temperature, 500 ml of DMSO were first pumped in, followed by a solution of 450 g of KOH in 250 ml of H ₂ O (about 500 ml). When the KOH solution was metered in, the exothermic reaction commenced, with the reaction temperature being limited to the specified maximum values by jacket cooling. The pressure dropped during the

Dosage time of the KOH solution (30 min.) Significantly.

After completion of the reaction, the gas phase was expanded over 3 with 250 g conc. HCl filled wash bottles, the reactor was heated to a maximum of 50 ° C. Methylphosphane (bp: -17 ⁰ C) and a portion of the ethylphosphine formed (Kp:

25 ^° C.) or dimethylphosphane (bp 21 "C.) were quantitatively intercepted in the form of their HCl adducts, while residual gases which had not absorbed (purge nitrogen, possibly unreacted PH ₃ and also methyl or ethyl chloride) were incinerated in a downstream combustion chamber For the quantitative analysis of the products formed, P elemental analyzes of the HCI and the HCI were performed

DMSO solution used in conjunction with ³¹ P NMR spectroscopy.

No phosphorus could be detected in the aqueous phases (<0.1%).

As Table 2 below shows, working in aqueous alkali hydroxide solution is surprisingly advantageous.

According to Comparative Example 9, when using solid alkali hydroxide, a significantly poorer conversion of the PH _{3 is} observed. Another disadvantage is also high proportion of unwanted Trimethylphosphanoxid in the DMSO phase.

Possibly under the reaction conditions described in Example 9 also trimethylphosphane (bp: 40 ° C) in

considerable extent, which is oxidized rapidly by DMSO to the corresponding phosphine oxide.

273 * 3 *

a 0) ο? Λ 31 < 3.7 (82) I 3.8 (85) 3.0 (67) 27.0 (73) 8.1 (75) UN <Τ <Γ α ProdukL CN X α_ ι ί * Ν CN ΰ CN. α CN ~ (Λ CN -τ- U. "Λ X U CJ ι CN α I CN ΰ-OI I fO CJ CN j_ α. ι CN CJ I ΰ Il CN T "U CN oil I Γ * ν, / - * CN CJ - * ι CN Q. CN α. CN ΰ α. CN in ~~ νθ U Reac- tion conditions CJ α α CN V. U α α CN \ CN U 3 α νθ SZ. νθ U α α U α α CN * ν. C CN U 3 σ CN "^ CN .σ - ¹ in = Q 150 150 150 500 500 1 300 I <-H: OO -J § - (US α & ³⁶ a? Ct ιΑ IA Γ » 650 300 300 ^ »Α S N a CT a α IA νθ <r U I ΛΛ CN ΰ I CJ α ιΑ σ \ νθ α ι CN ΰ I α u "\ * S νθ.-Λ CJ ι CN CJ I a" "α ι. • Λ ΰ α α VA tA α νθ! • 4 ι CN ΰ ι ΰ II CN CJ α α i-i CN α CN ^ t CQ I _CN CJ ι CVI ΰ I _CN CJ I C2 ο α -ι '<r CN »-Η CJ CN ΰ CL CN u- \ ~ vO CJ i CV

belle

[iei u ρ i

Pll g (mol)

Alkylol alogenide g (mol)

Reaction Appraisals

Product distribution IICl absorber DMSO phase

(MoI JS)

(MoI SS) product quantity

HCl absorber

DMSO phase (Q)

Unmet ^ tJi Kjsrjrad be * . on Pll,:

(1.0)

CII Cl (2,0)

30 ': 15 ⁰ C 3 h: 25 ⁰ C Pniax: 5 bar final pressure: 1.7 bar

CH, PH ₉ : (CIK) ₉ PII: (CH,), P: <0.2

> 37

5.5 <0.2

9Ü

39 (1.15)

, 5)

5 hs 14 24 ° C

Pniax: 4 bar ultimate pressure: 0.5 bar

C ₂ H ₅ PH ₂ :

25

94 %

Comparative example

39 (1.15)

with 2 30 g solid, powdered KOII:

CII Cl (2,0)

3 h: 20 24 ⁰ C

Pinax: 7.5 bar E η d d e r c k: 2.2 bar

CH, PIL · CIK)

:

:

0.6

9 5 0,5

17

20

76 %

Claims (3)

1. Process for the preparation of phosphines of the general formulas R _n PH ₃ .n (0 H ₂ P- (CH ₂ ) _m -PH ₂ (II) or (C ₆ Hs) ₂ P-CH ₂ -PH ₂ (III) _f in which R eeee is a straight-chain or branched alkyl group having 1 to 24C atoms or a cycloalkyl, benzyl, or allyl group, m is 2,3 or 4 and η is 1 or 2, characterized in that phosphine in the presence both a 50 to 70Gew .-%, aqueous alkali hydroxide solution and of dimethyl sulfoxide with reagents of the general formulas RX, X (CH ₂ ) _m X or (C ₆ Hb) ₂ P-CH ₂ -X, in which R and m have the meanings given and X is chlorine or bromine, at temperatures between 0 and 70 ⁰ C and an excess pressure of 0 to 10 bar is reacted, wherein per mole of X in each case at least 1 mole of alkali metal hydroxide. 2. The method according to claim 1, characterized in that one carries out the reaction at temperatures of 0 to 50 ⁰ C. 3. The method according to claim 1 or 2, characterized in that one carries out the reaction at overpressures between 0.1 and 8bar.