CS238918B1 - Process for the preparation of bis / triphenylphosphane oxide / tritio-cyanocarbonate complex - Google Patents

Abstract

The invention relates to a method for preparing a bis/triphenylphosphine oxide/trithiocyanate-iron complex of the formula Fe/NCS/,Ph,PO/,, where Ph denotes phenyl. The essence of the method according to the invention consists in reacting iron compounds selected from the group consisting of an elemental metal and salts of strong inorganic acids with alkali metal thiocyanates and triphenylphosphine in acetonitrile in the presence of dioxygen. The said complex is used as a catalyst for the oxidation of triphenylphosphine with dioxygen to triphenylphosphine oxide.

Description

The invention relates to a method of preparing a bis/trienylphosphane oxide/trithiocyanate iron complex of the formula Fe/NCS/j/Ph^PO/j, where Ph here and hereinafter means phenyl.

This compound is used as a catalyst in the oxidation of triphenylphosphine Ph^P with dioxygen according to the invention AO No. 205 483 and is also a potential catalyst for the oxidation of various substrates such as tertiary phosphanes and arsanes, olefins, alkylbenzenes, styrene.

The complex of composition Fe/NCS/ ₃ /Ph^PO/j is prepared according to J. Chem. Soc. /A/ 1971, 850 by direct reaction of an ethanol solution of Fe/NCS/js with triphenylphosphane oxide PhjPO or according to AO No. 218 199 by reaction of Fe/NCS/^ with Ph^P in a molar ratio of 1 : 2 while supplying O ₂ in acetonitrile.

The disadvantage of the first preparation method is that Ph ₃ PO is used, which must be prepared by oxidation of Ph^P. The disadvantage of both methods is the need to prepare a Fe/NCS/ ₃ solution from anhydrous FeCl ₃ and KSCN.

The above disadvantages can be eliminated by the method of preparing the bis/triphenylphosphine oxide/trithiocyanate-iron complex according to the invention, the essence of which consists in reacting iron compounds selected from the group consisting of an elemental metal and salts of strong inorganic acids with alkali metal thiocyanates and triphenylphosphine in a molar ratio of 1:3:2 in acetonitrile in the presence of dioxygen at temperatures of 20 to 80 °C.

If the molar ratio of the above substances is not maintained, then in addition to the Fe/NCS/ ₃ /Ph ₃ PO/ ₂ complex, after the reaction is complete, a portion of the unreacted starting substances is found in the reaction mixture, except for triphenylphosphine, which is catalytically oxidized to triphenylphosphine oxide.

When using ferrous chloride FeCl ₂ and potassium rhodanide DSCN, potassium chloride KC1 and ferric oxide Fe ₂ O ₃ are formed as by-products, the formation of which can be minimized by adding thiocyanate anions NCS to the fairy iron or solution.

When starting materials are hydrates of ferric sulfate or ferrous iron powder, potassium rhodanite and sulfuric acid, the by-product is potassium sulfate. After the reaction is complete, the reaction mixture is filtered and from the filtrate, after cooling, violet crystals of the composition Fe4'CS/ ₃ /Ih ₃ PO/ ₂ gradually crystallize, which are recrystallized. At a concentration of iron in oxidation state III, II or O equal to approximately 0.1 M in acetonitrile of approximately 30 cm ³ / while maintaining the above-mentioned molar ratio, the Fe/N CS/ ₃ /Ih ₃ P0/ ₂ complex can be obtained with the addition of O ₂ in 2.5 to 50 hours, depending on the starting iron compound used.

Increasing the temperature above 50°C accelerates the reaction, but increases the loss of acetonitrile by evaporation. Lowering the temperature below 0°C prolongs the reaction time. The subject of the invention is described in the following examples.

Example I

In a temperature-controlled reaction vessel (50 °C) flushed with oxygen, 2.5.10 ⁴ moles of Fe2/SO4/3 .9H20, 1.5.10 ^-3 moles of KSCN and 10 ^-3 moles of Ph3P are placed and, after connection to the apparatus for measuring O ₂ consumption, 10 cm ³ of acetonitrile is dosed.

By monitoring the dependence of 0 ₂ consumption on time, it was found that the oxidation of Ph ₃ P to Ph ₃ PO lasted 6 hours. The obtained crystals of Fe/NCS/ ₃ /Ph ₃ PO/ ₂ were recrystallized from acetonitrile.

and after drying at room temperature, they were subjected to elemental analysis Analysis results: Fe C H N calculated /%/ 7,099 59.54 3.84 ^5.34 found /%/ 7.12 59.60 3.88 5.10 The yield was 85%.

0.6 g of Fe(II)SO(II)OH(II)O - ferric sulfate, 1.1 g of Ph(II)P - triphenylphosphine, 0.6 g of KSCN - potassium rhodanide are weighed into the reaction vessel and 25 to 30 cm ^{2 of} acetonitrile are added.

The reaction mixture is heated at 55 °C with the addition of dioxygen and stirred for 7 hours.

Example 2

After filtering off the solids from the reaction mixture, a purple-red powder was obtained after evaporation of the solvent, which was recrystallized. The obtained Fe/NCS/j/PhjPO/j were dried and subjected to analysis.

acetonitrile from filtral crystals composition

Analysis results:

Fe calculated /%/ 7.099 found /%/ 7.08

The yield was 85%.

C H N

59.54 3.84 5.34

59.90 3.90 5.25

Example 3

0.6 g of ferrous sulfate FeSO4, 1.1 g of triphenylphosphine Ph2P, 0.6 g of potassium rhodanine KSCN and about 30 cm 3 of acetonitrile are placed in a reaction vessel heated to 60°C and dioxygen is introduced with constant stirring.

The oxidation of Fe ¹¹ to Fe ¹¹¹ and Ph^P to PhjPO lasted about 50 hours. The reaction was accelerated by adding a few drops of concentrated HjSO^. After filtering off KjSO^ as a by-product, or possibly unreacted FeSO^, Fe/NCS/j/Ph^PO/j crystallized from the filtrate. The obtained violet crystals can be recrystallized.

Analysis results:

calculated /%/ found /%/

Fe CH 7.099 59.54 3.84 7.11 59.90 3.92

N

5.34

5.22

The yield was 60%.

Example 4

0.09 to 0.1 g of 0.8 f triphenylphosphine 3 3 is placed in a temperature-controlled reaction vessel /40 °C/

Ph^P, 0.44 g of potassium rhodanide, 0.13 cm 93% H, SO^ and 30 cm 1 of acetonitrile are added and Oj is added with constant stirring.

The oxidation of Fe° to Fe ¹¹¹ and Ph^P to PhjPO lasted 10 hours. After filtering off the cured KjSO^ and possibly unreacted starting materials, purple crystals of the composition Fe/NCS/j/Ph^PO/j crystallized from the filtrate. After recrystallization and drying, the substance was subjected to analysis.

Analysis results:

Fe calculated /%/ 7.099 found /%/ 7.09

The yield was 85%. C Η N

59.54 3.84 5.34

59.45 3.80 5.30

I

Example 5 about “4

5.10 mol of FeCl» is placed in a temperature-controlled vessel (50 C) flushed with oxygen.

-3 - 3 &

1.5.10 mol KSCN, 10 mol Ph,P and after connecting to the apparatus for measuring the consumption of dioxygen-4 & 3 ka, 5.10 mol HCl in 10 cm acetonitrile are dosed.

By monitoring the dependence of dioxygen consumption on Sas, it was found that the oxidizing cycle lasted 140 min. After filtering off the secondary product /KCl/ from the solution, the complex Pe/NCS/ ₃ /Ph ₃ PO/ ₂ crystallized.

Examples

To a reaction flask containing anhydrous ferrous chloride (0.07 g), potassium rhodanide (0.07 g) and 0.27 g of triphenylphosphine is added 10 cm ³ of acetonitrile and, with the addition of O and stirring, the reaction mixture is heated at 50 °C for 3 hours.

•'l

After filtering off the by-products (KCl and Fe ₂ O ₃ ), the Fe/NCS/ ₃ (lh ₃ K)/ ₂ complex was isolated from the filtrate. After recrystallization and drying, the obtained purple crystals were subjected to analysis.

Analysis results:

calculated /%/ found /%/

FeC

7,099 59,54

7.13 59.92

H N

3.84 5.34

3.91 5.24

The yield was 50%.

The identification of the preparations according to Examples 1 to 6 was carried out by measuring the electron and infrared spectra. The end of the oxidation of PhjP to Ph ₃ PO was determined by comparing the electron spectrum of the product with the spectrum of pure triphenylphosphine oxide Ph ₃ PO, which has four absorption bands with absorption maxima in the region of 254, 260, 265 and 272 nm in acetonitrile solution.

The presence of coordinated PhjPO in the sample was confirmed by / i ⁷ p_θ = 1 143 cm ¹ /. For uncoordinated PhjPO, it was proven by measuring infrared spectra at p_ ₀ and 1 190 cm ^-1 .

Claims (1)

I 238918 Example 5 o “4 Into a tempered vessel (50 C / oxygen purged) insert 5. 10 mdl FeCl »," 3 - "3 & 1.5. 10 moles of KSCN, 10 ml of Ph, P and, after connection to a consumption measuring apparatus, with D-4 & 3 ka is dispensed 5. 10 mol of HCl in 10 cm of acetonitrile. By monitoring the consumption of di-oxygen from Sasu, it was found that oxidation lasted 140 min. After filtering off the by-product (KCl) from the solution, the complex P e / NCS / 3 / Ph 3 PO / 2 crystallized. Example To a reaction flask containing anhydrous iron (II) chloride (0.07 g), potassium rodanide (0.07 g) and 0.27 g of triphenylphosphane was added 10 cm @ 3 of acetonitrile and heated to 50 DEG C. for 3 hours under stirring and stirring. . After filtering off the by-products (KCl and Fe 2 O 3), the Fe / SCS / 3 / 1h 3K / 2 complex was isolated from the filtrate. For recrystallization and drying of the obtained purple crystal, analyzed, Analysis results: calculated /% / found /% / Fe C 7,099 59.54 7.13 59.92 Η N 3.84 5.34 3.91 5.24 Yield was 50%. Identification of the preparations according to Examples 1 to 6 was carried out by measuring the electron and infrared spectra. The end of PhiP oxidation to Ph3PO was determined by comparing the electrode spectrum of the product with that of pure triphenylphosphane oxide Ph3PO having four absorption bands with maximum absorption at 254, 260, 265 and 272 nm in the acetonitrile solution. The presence of coordinated PhpPO in the sample was 77p_θ = 1,143 cm 1 /. For uncoordinated PhJP0, p_0 * 1119 cm @ -1 was measured by measuring infrared spectra. DISCLOSURE OF THE INVENTION A process for preparing bis / triphenylphosphane oxide / tritio-cyanate iron complex of formula Fe / NCS / 3 / Ph 3 PO / 2, wherein Ph is phenyl, wherein the iron compounds selected from the elemental metal and strong inorganic acid salts are reacted with alkali thiocyanates metal and triphenylphosphane in a 1: 3: 2 ratio of aceto-nitrile in the presence of dioxygen at 20-80 ° C. Severografia, n. P., MOST Price 2,40 Kcs