DE1903968A1 - Thiophenols with the sulphides or polysul- - phides of cobalt and nickel as catalyst from - Google Patents

Abstract

Thiophenols with the sulphides or polysulphides of cobalt and nickel as catalyst, from water containing diaryl-disulphides. Method of preparation of thiophenols by reduction of the respective diphenyldisulphide. A solution of the diphenyldisulphide is treated with H2 at raised pressure and in the presence of a catalyst at a temp. between 60 degrees and 300 degrees C to produce the corresponding thiophenol. Catalyst is the sulphide or polysulphide of Co or Ni. Suitable aromatic disulphides are complexes of general formula:- where R = H halogen or alkyl. n = a whole number between 1 and 5.

Description

Production of thiophenols with the sulfides or polysulfides of the cobalts and nickel from hydrous diaryl disulfides.

The hydrogenative cleavage of aromatic disulfides under the influence of catalysts has been carried out for a long time.

in US Pat. No. 2,402,694, on hydrogenative cleavage reported from dinaphthyl disulfide to naphthyl mercaptan on iron polysulfide contact. After that, the feed must be dry, and the catalyst is also before it Use has been freed from the adhering water. Both make a very sizeable one Expenditure prior to the hydrogenation.

The invention relates to a process for the preparation of thiophenols by reducing diphenyl disulfides with hydrogen under pressure over a catalyst at temperatures between 60 and 3000 C, which is characterized in that one a sulfide or polysulfide of cobalt or nickel is used as a catalyst.

These catalysts can easily be made more water-soluble by precipitation Manufacture cobalt or nickel salts with sodium sulfide or polysulfide. You need no further treatment and are immediately ready for use after filtering off. Under the influence of these catalysts, aromatic disulfides are produced in high yields and of excellent purity hydrogenated to the corresponding thiophenols.

It is best to proceed in such a way that the liquid resp.

molten diphenyl disulfides the catalyst in amounts of about 0.5 to 10 ffi, preferably 1-5, added and at hydrogen pressures of 150 atm hydrogenated. Solvents can be used in this process, however their absence leads to improved space-time yields. After the Reactions are sucked off the thiophenols from the catalyst.

Particularly noteworthy is the fact that the catalysts also maintain their effectiveness unchanged in the presence of water and as often as desired can be reused. The process can be continuous or discontinuous be performed.

Suitable aromatic disulfides are compounds of the general formula where R = hydrogen, halogen or alkyl and n is an integer between 1 and 5.

Example 1 13 g CoSO4. 7 H20 are dissolved in 15 g of water at 400 and with a solution of 6.2 g Na2S, which contained 40% water, dissolved in 15 g water, offset. The precipitated cobalt sulfide becomes sulfate-free 4 times with 25 ml of water each time washed and sharply vacuumed and dried on the clay plate.

In a 700 ml autoclave, 200 g of diphenyl disulfide, which is 0.1% Contains water, in the presence of the cobalt sulfide catalyst prepared above 150 atm hydrogen hydrogenated. The reaction starts at 1380 and proceeds by ramping up to 1800 within 10 minutes. The resulting thiophenol contains less than 0.1 fi diphenyl sulfide and 0.8% iiphenyl disulfide; the yield is thus 99.1 ,.

Example 2 13 g CoSO4. 7 H20, dissolved in 15 g of water at 400, are to be with a solution of 6.2 g Na2S, which contains 40% water, in 15 g water. The precipitated cobalt sulfide is washed free of sulfate four times with 25 ml of water each time, then sucked off sharply and reused with water. 200 g of diphenyl disulfide will be mixed with 2 g of water and the cobalt catalyst and hydrogenated.

The start of the reaction is 1390. The hydrogenation is complete after 15 minutes. The resulting product is examined by gas chromatography. It contains 99.8% Thiophenol, less than 0.1% diphenyl sulfide and 0.1% diphenyl disulfide.

Example 3 200 g of diphenyl disulfide are mixed with 2 g of water and with a cobalt sulfide contact made as described in Example 2 is, hydrogenated at a hydrogen pressure of 150 atmospheres 0. The reaction starts at 138 and increases to 1800 within 10 minutes. The reaction product is filtered off from the contact; it contains less according to gas chromatographic analysis as 0.1% diphenyl sulfide and 0.1% starting product.

Yield of thiophenol 99.8.

Example 4 As in Example 3, 200 g of diphenyl disulfide with 2 g of water have been added, in the presence of that recovered from Example 3 Hydrogenated cobalt sulfide catalyst. The reaction starts at 1480 and is after 20 Minutes ended at 1800. The thiophenol is 99.8%; it contains less than 0.1 ffi diphenyl sulfide and less than 0.1% diphenyl disulfide.

Example 5 13 g NiS04. 7-H20 are dissolved in 15 ml of water and at 400 mixed with a solution of 6.7 g of 60% sodium sulfide in 15 ml of water while stirring. The resulting nickel sulphide precipitate is as in example 2 described for cobalt sulfide, reused when water-moist.

200 g of diphenyl disulfide to which 2 g of water have been added hydrogenated in the presence of the nickel sulfide catalyst thus prepared. The reaction starts at 1780 and finishes at 2000 after 40 minutes. The resulting thiophenol contains 0.8 ffi diphenyl sulfide and less than 0.1% 0 starting product; the yield is 99.1 ß d. Th.

Example 6 3.08 g of sulfur flowers are added to a solution of 6.2 g Sodium sulfur in 16 ml of water and stir for 90 minutes at 700. The resulting yellow The solution is added dropwise to a solution of 13 g of CoSO4 while stirring. 7 H20 in 15 ml of water. The precipitate is filtered off with suction, washed free of sulfate and washed 4 times with 25 ml of water each time dried on the clay plate.

200 g of diphenyl disulfide, which contains 0.1% water, is in the presence this xobalt trisulfide contact is hydrogenated at 150 atmospheres hydrogen pressure. The reaction starts at 1400 and finishes at 1800 in 7 minutes. The resulting reaction product contains less than 0.1% diphenyl sulfide and 1.5% diphenyl disulfide. The yield of thiophenol is 98.4%.

Example 7 A cobalt sulfide catalyst prepared according to Example 1 is added to 200 g of diphenyl disulfide and 8 g of water and the mixture at 150 atm hydrogenated with hydrogen. The reaction starts at 1390 and becomes progressive at 1750 finished in 10 minutes. The resulting thiophenol contains 0.1% diphenyl sulfide and 0.1% diphenyl disulfide. Yield 99.8% of theory Th.

Example 8 The cobalt sulfide catalyst recovered from example 7 is added to 200 g of diphenyl disulfide containing 0.8% water and 6 g of water and hydrogenated as described in Example 1. The response starts at 1400 and becomes finished within 13 minutes at 1800.

The resulting thiophenol contains 0.1% diphenyl sulfide and 0.1 ffi Diphenyl disulfide; Yield 99.8% of theory Th.

Example 9 The catalyst recovered from Example 8 becomes 200 g of diphenyl disulfide and 8 g of water are added, and, as indicated in Example 1, hydrogenated. The reaction begins at 1400 and is at over 15 minutes 175 finished. The resulting thiophenol contains less than 0.1% diphenyl sulfide and 0.1% diphenyl disulfide; Yield: 99.8% of theory

Example 10 41.5 parts by weight of 2,2,5,5'-etrachlorodiphenyl disulfide are mixed with a contact in the melt that contains approx. 40% water. It is prepared in the following way: 7.6 parts by weight of crystallized material are dissolved Cobalt sulfate heptahydrate in 35 parts by volume of water, brings the cobalt sulfide through a solution of 3.6 parts by weight of sodium sulfide trihydrate in 35 parts by volume of water for balling, sucks off the resulting black precipitate and washes with water. Hydrogenation takes place at 1800 and a hydrogen pressure of up to 150 atm. After completion During the reaction, the reaction mixture and the remaining catalyst are filtered off with suction washed with benzene. When the combined filtrates are distilled, one obtains a Fraction boiling at 700 and 1.1-1.5 Torr: 38 parts by weight of 2,5-dichlorothiophenol corresponding to a yield of 92% of theory. Th.

EXAMPLE 11 139 parts by weight of bis (p-tert-butyl-phenyl) disulfide are added with 4% = 5.5 parts by weight of water and adds a catalyst that through Precipitation of a solution of 15.2 parts by weight of cobalt sulfate heptahydrate in 70 parts by volume Water with a solution of 7.2 parts by weight of sodium sulfide trihydrate in 70 volumes share water, then suction and wash with water is. Under a hydrogen pressure of 150 att at a temperature of 1800 hydrogenated. The reaction is over after 3/4 hours.

The mixture is then sucked off and the one remaining in the filter Contact washed with benzene. The filtrates can be obtained by distillation 136 Parts by weight of p-tert-butylthiophenol = approx. 98% of theory obtain. '

Claims (1)

Claim 1. Process for the preparation of thiophenols by Reduction of diphenyl disulfides or of solutions of diphenyl disulfides in the corresponding thiophenols with hydrogen under increased pressure and in the presence of catalysts at temperatures between 60 and 3000C, characterized in that that a sulfide or polysulfide of cobalt or nickel is used as the catalyst.