DE1816902A1 - Process for the preparation of symmetrical diaryl disulfides - Google Patents

Description

PAINT FACTORY ^{BAYERAG 1816902}

LlVEftKUSEN-Bayenrak f »« at-abbot «Unn§ Hu / lIM

Process for the production of symmetrical diaryl sulfates

The present invention relates to a novel method of manufacture of symmetrical diaryl disulfides by reduction of Arylsulfinsäursn in aqueous medium with sulfur dioxide without or with hydrogen iodide as a catalyst.

Ss is already known (see. For example, "Houben-Weyl, Methods of Organic Chemistry""4th Edition, Vol. IX, pages 59 to 82) that symmetrical diaryl disulfides by oxidation of Aryimerkaptauen, arylation of dinabrium disulfide, sulfur introduction by means of elemental sulfur or Disulfur dichloride, from thiocyanic acid, tbaw. Thiosulfuric acid esters and by reducing aryl sulfonic acids can be prepared. In the reduction of arylsulphonic acids or the corresponding derivatives, preferably aryisulphonic acid chlorides and their polar products such as sulphinic acids, thiosulphonic acid esters and sulfenic acids, zinc, phosphorus, alkali iodide _9, iodine, etc. are used. Proposed hydrogen bromide as a reducing agent.

So reduce ζ-B ₀ P. T ₀ Cl © vs / Serichte der Deutschen Ö © s © ll8chaft ₉ Bd ₀ 2O ₉ S.! 534? Vol. 2 ± ₉ S ₀ 1099; Vol. 2.3, p.958? 3 ^ «. ^, J p. 2485 ^ 7 as well as L. Bauer and J. Cymermann / "Journal-of Oefae Chemical Society (London), (1949)" 3.3434 ^ JlItTObOnZoI- or lisr-onaphthalenesulfonic acid chloride with hydrogen iodide in glacial acetic acid with added acetone the. corresponding. Dinltrodiaryldisulfiden. Jl ₅ Skborn / "" Reports of the German Chemical Society, Bd * Z ^ So 1118;, Vol. 2 £ ₅ p. 329_ / receives in the reduction of ai-'5rosaphthalin® »ilfonsäureami (i with Hydrogen iodide and red Phs-s with simultaneous reduction of the nitro group dae

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corresponding Diaminodinaphfchyldlsulfid. Zinc as a reducing agent is used by RN Johnson and ΰ. Smiles ^ / Journal of the Chemical Society / Xondon_7, Vol. 123 ι & 2384 7, as well as by E. Vinkler and F.Klevenyi / Acta chim. Acad. May be. Hung. Ed. J_, p. 319 (1951) _7 used ^{for the} preparation of disulfides. K. Pries, G. Schürmann, W. Vogt and E. Engelbertz / Reports of the German Chemical Society, Vol. £ 7, p. 1195; Liebigs Annalen der Chemie, Vol. JJjBI _- , p. 332; Vol. 407 , p. 217_7 and A. Reissert / Reports of the German Chemical Society, Vol. ^ 5yS.858_J7 use sulfinic acids as starting materials and reduce them with the help of hydrogen bromide in glacial acetic acid.

It is also known that symmetrical diaryl disulfides are obtained (cf. the IJ.S.A. patent specification 2,571,740) if one Arysulphonic acid chlorides with sulphites or sulfur dioxide and iodine waters Soffic acid in an organic or aqueous solution Medium reduced.

However, all the methods mentioned have a number of disadvantages and are hardly suitable for carrying out technical analyzes »

Many of the implementations are very cumbersome, sometimes over several stages or are uneconomical because the costs for the Outgrowth materials are too high (e.g. aryl mercaptans, thiocyanic acid esters), or they give non-uniform products, which leads to unsatisfactory yields and makes additional purification operations necessary (arylation of disodium disulfide and other sulfur introduction). Also those for the reduction of aryl sulfonic acid chlorides and their reduction products required reducing agents (iodine or hydrogen bromide, zinc, Phosphorus) represent a heavy burden in terms of costs, especially since large quantities of it are required, since the reaction Ub * r ■ • hrtr « re reduction stages runs. Many procedures require aues ^ ruem the presence of an organic solvent and thus mostly the arylaulfonic acid chlorides used as starting materials in anhydrous form.

For example, Marson (US Pat. No. 2,571,740) used in reducing

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BATH ORIGINAL

tion of sulfonic acid chlorides with sulfite or sulfur dioxide and hydriodic acid, glacial acetic acid, dioxane or methyl ethyl ketone as solvents. He also works in an aqueous medium.

Compared to the addition in organic solvents, Itarson requires a multiple of the amount of hydriodic acid in the aqueous medium, namely 0.2 to O ₅ β mol, preferably O ₉ 5 mol, per mole of sulfonic acid chloride in order to achieve satisfactory yields and is limited to that Description of the reduction of a single product, namely 3-HitrobenzenesulfonsäureehlQriä.

It is also known from the literature that the reduction of sulfonic acid chlorides, in particular in an acidic aqueous medium, especially at a higher temperature, often only gives moderate yields of biaryl disulfides or aryl mercaptans (see ^M Houben-Weyl, Methods of Organic Chemistry ", 4 . Edition, Vol. IX, pages 30 and 31). The reaction proceeds through the following stages "

2 R - SO ₂ Cl- * 2 R- - SO ₂ H - 1 R-SO ₂ -SR - * RSSR - »2 R-SH

In order to lower the yield, the reaction sequence described above should be used occurring arylsulfinic acid be responsible «The latter is unstable and is easily disproportionated in the sulfonic acid converted, in contrast to the sulfonic acid chloride not reduced to diaryl disulfide or aryl mercaptan can be (see. "Houben-Weyl, methods of organic chemistry", 4th edition, Vol. IX, pages 331 and 332) ·.

3R- SO ₂ H - ¥ R-SO ₂ -SR + R-SO, H + HgO

5 R - SO ₂ H - »RSSR + 3 R-SO, H + H ₃ O

In the above equations, R stands for an optional substituted aryl radical. According to this prior art, aloo had to expect that when using aryl sulfinic acids instead of Arylsulfonsäurechloriden as starting materials for the reduction and the reaction likewise do not proceed uniformly and only unsatisfactory yields are obtained.

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It has now surprisingly been found that symmetrical diaryl disulfides are obtained in approximately quantitative yield and with a high degree of purity if arylsulfinic acids are used in an aqueous acidic medium without or in the presence of hydriodic acid or substances which form hydriodic acid under the reaction conditions as a catalyst with sulfur dioxide or sulfur-donating agents at temperatures between ⁰ C and 20O ⁰ C 4 preferable + 2O ⁰ C and 4130 ^0C, reduced. The course of the process according to the invention is represented by the following equation, in which R has the meaning given above:

2 E-SO ₂ H + 3 SO ₂ - »RS-ö-R + 3 SO, + H ₃ O

The course of the inventive process, after which also obtained at reaction temperatures above 100 ⁰ C, and without using a catalyst diaryl disulfides in almost quantitative yields, could be foreseen in any way.

Instead of arylsulfinic acids, the same can be used according to the invention The corresponding sulfonic acid chlorides were also successful as starting materials are used, which, however, must be done beforehand in order to prevent saponification of the same, according to known methods, eg by reduction with sulphite in neutral to weak alkaline aqueous medium (e.g. after "Houben-Weyl, Methods of Organic Chemistry", 4th edition, Vol. IX, page 306 ff), in transferred the sulfinates in question, and these without intermediate isolation further reduced directly or after acidification according to the present invention. This procedure saves you not only isolates the sulfinic acid, but at the same time prevents the associated yield losses, to a limited extent due to the solubility of sulfinic acids in water. Since the reduction of sulfonic acid chlorides to the corresponding sulfinates or sulfinic acids generally proceed approximately quantitatively, the yields of diaryl disulfides are also based on sulfonic acid chloride used, very high.

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8AD ORIGINAL

As starting materials for the process according to the invention, aromatic sulfinic acids or the corresponding sulfonic acid chlorides, in particular of benaol and naphthalene, their aromatic radical; optionally sin = -or multiply substituted 1st., © are set ,. As such Substitusnten example gsnann.ts halogen (chlorine, bromine, iodine, FIuOi) _selenium-9 alkyl (straight chain or branched, having 1 to 5 carbon atoms), aryl - (? H © = - nyl or Maphthyl optionally substituted). Hydroxyl-, alkoxyl (with 1 to 5 carbon atoms), amino _s alkylasiino (with 1 to 5 carbon atoms) ρ dialkylamino (each with 1 to 5 carbon atoms), arylaino (phenyl or haphthyl, optionally substituted) j acetamido »carboxyl» nitro 9. Sulphonic acid, sulphonamido-j, arylsulphone (phenyl or Iaphthyi ₅ optionally substituted) or thioic groups.

Examples are, for example, the following sulfinic acids (bz ™ ro ds- τ®η corresponding sulfonic acid chloride ©) listed Bensd-, 4- ¹ Ci hl or-, 2 ₉ 5- and 35 4-dichloro-j, 4-mathyl- ₀ 4 = -Acs'öamiio- = ₃ 4-Ms tr. = O3ry = 3-acetami .0-, 3-carboxy- =. 4-feydroxy- ₉ 3-Carboiry - 4-chior » ₉ 3-Hitro-, 2-methyl-5-nitro- _B 3-Iitro-4-methyl- ₉ 2-ChIoi ° -5-aitT-5- ₅ 3-Hitro-4-chloro-, 2 ₉ 4-dimethyl-3-nitrobenzenesulfinic acid, isrwss ¹ 2'-Nitrodiphenyl-sulfonsulfinic acid ^ s Benaozaaolon-j Glorbensosaaolonsulfinic acid, Maphbhalinsulfinic acid-2 and 1-Carboxy-2-hydr © xy-BEphthalinsulfinic acid -6ο

üis is "already mentioned above, the verfahrensgesaässe Rsduktioa in acidic medium performed ₅ d" h. one would use the aryl silicate acids in the form of their free acids? the corresponding aryl sulfinates must first be transferred beforehand. This Iraan SCBO by the addition of 1 mole of mineral acid per mole of 3alfinat happened In üinEatz of Schwofoldioiria as Saduküi ^ ns-βίΐΐβΐ often the thickness ranges of sulphurous acid from _s to &'λχ UeTi sulfinates the acids in freedom to set "If the neutral or acidic salts of sulphurous acid, especially if used, care must be taken (possibly by adding further mineral acid; that a pH value of 3 is not achieved.,

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As a reducing agent, it can supply sulfur dioxide as well as sulfur dioxide Agents such as the neutral or acidic salts of sulphurous or sulphurous acids are used. To be reduced per mole Suific acid is expediently used up to 1.5 moles 5.0, preferably!, 5 moles to 2.5 moles, sulfur dioxide.

According to the method according to the invention, exclusively in Water worked as a solvent; it can be derived from this Make basic principles particularly economical. The reduction of sulfinic acids is 70η the amount of water used as the reaction medium As far as possible independent, so the ciasa for large-scale technical approaches the most favorable concentration can be chosen freely.

Jj.ie presence of a catalyst is not required for the smooth progress dea method, however, reaction time and temperature-kc can sometimes hfabgssetzt vvorf ¹ n when small amounts. Hydriodic, or such substances as catalysts _t - _r used that form under the / out conditions Jodwasseret of fs ti acid. For this purpose Korea. preferably into consideration: iodine, Mcteill-j -7, 'J- ΐ-aU ^1;. a; ii-, KaL ,; Jtij ™. rlei- · or copper iodide, and Ni ', :: ¹ , SrtE-r tall j, χΠ, ΰ-β, 2 »Β. Jrhosphor iodide. From 0 to 0.1 mol, preferably from 0 to 0.025 mol of hydrogen iodide , are expediently used per mole of sulfinic acid or the precipitating sulfonic acid chloride.

The reaction temperatures can be within a larger range can be varied. In general, one works between 0 and +200, preferably between +20 and + 130 ° above sea level,

In most cases it is not absolutely necessary to carry out the process according to the invention under pressure. However, in order to avoid losses of the volatile sulfur dioxide and to increase the concentration of the latter in the reaction mixture, it has been found to be advantageous to carry out the reaction in one. closed system, optionally under pressure, to proceed% can u. In general, a bridge between 0 and 10, preferably between 1 and 5 atmospheres, is used.

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BATH ORIGINAL

The products of the process are isolated; as they gröestenteiis are insoluble in water, very ftinfach "So the diaryl after cooling the lteaktionagemisches" can oei basic substances possibly by conversion to the free Ease in solid form or as long as the melting point of entertaining is 10O ⁰ G, are separated as an oily phase from the hot water The yields are 90 to 100%, based on the sulfic acid used, or 85 to 100 _%, calculated on the sulfonic acid chloride.

The products are obtained in a very high degree of purity, which means In most cases, have a proper cleaning operation unnecessary.

An advantageous embodiment of the method consists in that in the aqueous solution or suspension of the sulfinic acids a which are used as such or by reducing the corresponding- "~ the sulfonic acid is obtained, after any addition of the Catalyst and possibly in a closed system «sulfur dioxide initiates and the mixture thereby, to ReaktiomrlGsaperatur heated. The diaryl disulfides formed are isolated by separating them as a pest substance or in oily form.

The inventive method has compared to all other known Working method for the production of diaryl disulfides in particular from an economic point of view it has significant advantages and is therefore also preferably suitable for carrying out large-scale operations Asasätae.

Since hydriodic acid, if at all, only in catalytic amounts is used, the reducing agent is sulfur dioxide or its salts in contrast to the agents previously used for this purpose, such as zinc, phosphorus,. Iodine and hydrogen bromide, In terms of cost, there is no significant contamination of the end products. The same applies to the solvent used. Water ale SoXvene has opposed the use of organic solvents The additional advantage that the sulfonic acid chlorides used as the starting product are in water-moist form in which they usually incurred, can be applied. This will make the

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Conversion into the anhydrous sulfonic acid chloride by extraction with an organic solvent and then Saved distillation. In addition, they can be almost in water. isolate sparingly soluble di aryl disulfide in a simple way. There is no need to isolate the end product from the organic solvent or to work up the latter. Conditional due to the mild reaction conditions, especially when added catalytic amounts of hydrogen iodide, the reaction proceeds uniformly and with almost quantitative yields »side reactions, such as sulfur elimination, desubstitution etc. do not occur, which - as already mentioned - results in subsequent cleaning operations unnecessary in most cases. Ultimately, it is particularly useful for carrying out large-scale technical approaches Meaning that no special equipment is required; it is suitable any acid-stable apparatus, such as enamel kettles, is much more suitable. An explosion-proof system is not required since only water is used as a solvent.

The method according to diaryl available k: can be easily and in quantitative yield to the corresponding mercaptans reduced; They are therefore valuable intermediate products for the production of pesticides, pharmaceutical preparations and dyes.

The following examples explain the invention in more detail:

Example 1: Diphenyl disulfide;

16.0 kg of 95% sodium sulfite (120 mol) are dissolved in 69 liters of water in a 150 liter enamel kettle. At 50 to 55 ⁰ C run from a measuring vessel within 40 minutes, 20.0 kg of benzenesulfonic acid chloride (113 mol) to the mixture, with equal-

early addition of 18.1 kg of 50% sodium hydroxide solution (226 mol) pH value of 8 to 8.5 is maintained. The benzenesulfinate solution obtained is stirred for 30 minutes, and 15.4 kg of 37% hydrochloric acid are added (156 mol) and 300 g of 57 # strength hydriodic acid (1.34 mol) to the reaction mixture and closes the kettle. now sulfur dioxide is extracted from a bomb up to a pressure of approx.

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BATH ORIGINAL

Pressed 2 atmospheres, the mixture heated to 100 ° C within 60 minutes and stirred for a further 30 minutes until the pressure constant. A total of 11.6 kg of sulfur dioxide (181 mol) is consumed. The mixture is cooled to 70 to 80 ⁰ O, relaxed and the lower aqueous phase is separated off through the floor drain. The oil remaining in the kettle is washed hot with a little dilute soda solution until it reacts neutral and the diphenyl sulphide located below is separated off as an oil, which solidifies on cooling.

The yield is 11.45 kg (93 * 1 ° of theory, based on

Benzenesulfonic acid chloride) "

Schflielspunkbs 60 to 61 ⁰ G
Analyzes < $ 0.01> KaGl

<z0.01 1 " Na ₂ SO ₄
0.06 i H ₂ O

The diphenyl disulfide obtained is chromatographically uniform. Example 2%

The mixture is heated in a 150 liter Enamel Kesael ^ 2 kg waaaerfeuehte Benzoleulfinaäure (46.9 # pure product = IO5 ₉ 5 mol) at 50 ⁰ G, adds 238 g of 57 $ strength by weight hydroiodic acid (i, 06 mol) to the mixture , closes the kettle, pumps a total of 45 kg of a 38> igen liatrium hydrogen sulphide solution (164 mol) to the reaction table over the course of approx. 3 hours, heating it to 105 ° C. The pressure in the boiler rises to a maximum of 3 to 4 atmospheres. ^{The batch is subsequently stirred at 105 0} O for 30 minutes until the pressure is constant and then worked up as described in Example 1.

The yield is 10.95 kg (95.3 i "of theory), melting point of the crude 60 ° G"

The analytical data correspond to those given in Example 1.

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Example. 5; _ ^

Di ρ he η y 1 disu 1 f id:

In a 16 liter enamel kettle, 6150 g of water- moist ^{benzenesulfinic acid (50.8 1} IAgQ tariff = 22.0 mol) are slurried in 3, B liters of water and 50 g of 57 / Uge hydroiodic acid are added to the mixture. The boiler is then shut down, up to 2 atii of sulfur dioxide is pressed from a bomb at room temperature and the batch is rushed up. At about 60 ⁰ G, the reaction starts, wherein the inner door tempera the mixture without external heating until approximately 10O ⁰ C rises, and the pressure to 0.5 afcli decreases. ^{A pressure of 2 to 3 atu is maintained at 100 to 105 0} G by further addition of sulfur dioxide and the reaction mixture is subsequently stirred for about 2 hours until the pressure is constant. A total of 2.550 g of sulfur dioxide (36.8 moles) is consumed. The batch is cooled with stirring to room temperature "where you can relax the mixture at 8O ⁰ C and short air or Stokstoff by blows to expel excess sulfur dioxide. The diphenyl sulfide is isolated on a suction filter, washed with water and air-dried.

The yield is 2530 g (97.2 ρ of theory), melting point of the crude product 60 to 6I ⁰ C.

The analytical data correspond to those of Example 1.

W hen playing 4;
Di phen.y ldi sulfj.dt

Analogously to Example I, a benzenesulfinate solution is prepared from 353 g of benzenesulfonyl chloride (2.0 mol), 282 g of sodium sulfite (2.12 mol), 320 g of 50% sodium hydroxide solution (4.0 mol) and 1220 ml of water Ltr. enamel boiler with 272 g of 37> hydrochloric acid (2.76 mol) acidifying. Then the boiler g at room temperature sulfur dioxide 320 is closed, (5.0 mol) and the mixture was pressed at 120 ⁰ C heated with its Inrii pressure rises atm to 8.5. the mixture is stirred 8 hr. at 12O ⁰ C to 125 ⁰ C to constant pressure after the mixture is cooled to room temperature and let them. the Biphenyldisulfid is funnel in a heatable sheath from the aqueous phase separated off as Cl and solidified on cooling

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Iisehe Sal se

if not washed, contains T, 8% inorganic (Sodium chloride and sodium sulfate).

The yield of pure diphenyl disulfide is 186 g (85 »4 $ of theory). The melting point of the raw material is 59 to 60 ° C.

The product is chromatographically uniform.

Example 5i
Diphenyl disulfide:

1280 g of water-moist benzene sulphuric acid (66.5% product = 6.0 mol) are suspended in 1 liter of water in a 4 liter enamel kettle. After Verschliesoen dee vessel is pressed at room temperature 960 g of sulfur dioxide (15.0 mol), and the batch is heated to 130 ⁰ C, the internal pressure rises atm to 8, the mixture is stirred for 8 hr. At 13O ⁰ C bia constant pressure by, cools it down to room temperature and isolates the diphenyl disulfide as described in Example 3.

The yield is 568 g (86.9 $> of theory), the melting point of the crude product is 59 to 60 C.

The analytical data correspond to those of Example 1.

Example 6:

2.2 * -5 "S'-tetrachlorodiphenyl disulfide

In a charged with 1 l. Water reservoir, wherein 139 g of sodium sulfite (1.1 moles) are dissolved, contributes 60 to 65 ⁰ C. 277 g of 2,5-waseerfeuchtea Dichlorbenzolaulfonsäurechlorid (1.0 mole 76.3 £ pure product ), whereby a pH value of 11 to 11.5 is maintained by adding sodium hydroxide solution at the same time. The Sui finatlösung is stirred for 30 minutes, heated to 80 ⁰ C and filtered to remove small amounts of 2,2'-5,5'-Tetrachlordiphenylsulfon. The mixture is neutralized with a little hydrochloric acid, 5.6 g of 57 # strength hydroiodic acid (0.025 mol) are added, 160 g of sulfur dioxide (2.5 mol) are pressed into a closed 4 liter enamel kettle and the batch is heated to 85 ° C and stir

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em abbr

him 2 hours until the pressure is constant of 4.5 atu. After the mixture has cooled down, the 2.2 ^f -5,5'-tetrachlorodiphenyl disulfide is isolated as indicated in Example 3.

The yield is 168 g (94.4 # of theory), the melting point of the crude product is 79 to 81 ^° C.

The 2,2'-5,5'-tetrachlorodiphenyldi8Ulfid obtained is chromatographed uniformly.

example Ii

2.2 '-5.5'-Tetrachlorodiphenyldisulfidι

The experiment according to Example 6 is repeated, but without the addition of hydriodic acid. The reduction with sulfur dioxide is carried out, this time for 6 hrs. At 11O ⁰ C and a maximum pressure of 6 atm.

The yield is 163 g (91.6 i ° of theory), melting point of the crude product is at 79 to 81 ⁰ C.

The 2 _t 2'-5,5'-tetrachlorodiphenyl disulfide obtained is chromatographically uniform.

Example 8;

2,2'-5,5'-tetrachlorodiphenyl disulfide:

980 g of water-moist sodium 2,5-dichlorobenzenesulfinate (43.1 # product = 2.0 mol) are dissolved in 1.5 liters of water in a 4-liter enamel kettle. It closes the boiler, suppressed at room temperature, 340 g of sulfur dioxide (5 _t 31 mol) to the mixture heated to 110 ⁰ C, the internal pressure rises atm to 8, the mixture is stirred for 6 h. At 110 °, cooled it off and isolates the reaction product as described in Example 3.

The yield is 347 g (97.5% of theory), the melting point is 80 to 81 ^° C.

The 2,2'-5,5'-tetrachlorodiphenyl disulfide obtained is chromatographic uniformly.

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OBlGlNAi.

Example 9s "*%

4y4'-dichlorodiphenyl disulfide;

Starting from 226 g of water-moist chlorobenzenesulfonic acid chloride (1.0 mol of 77.1 following goods), the procedure is analogous to that described in Example 6.

The yield is 131 g (91.4 ° / ° of theory), melting point of the crude product is at 69 to 7O ⁰ G ₀

The 4,4'-dichlorodiphenyl disulfide obtained is chromatographic uniformly,

Belapiel 10s

4,4'-dichlorodiphenyl sulfide

In a 16 liter enamel boiler (66 ₉ 8'j £ pure product = 5 ₉ O mole) in S ₉ are dissolved 5 l water, 1320 g of water-moist i-chlorbsnzolsuifinsaures sodium. Adding to this solution 730 g 30 #igs Baissäure (6 O ₉ mol), verschrieest the boiler suppressed at room temperature, 960 g of sulfur dioxide (15.0 mol) to the mixture heated to 12O ⁰ C, the pressure to 7, 5 atü rises and the 5 ütd stirs. until the pressure is constant. The preparation of the approach is carried out as indicated in Example 3 »

The yield is 694 g (96.6 i ° of theory), melting point of crude product is 69-70 ⁰ G.

The 4,4 "-dichlorodiphenyl disulfide obtained is chromatographic uniformly.

Example 11;

4.4'-dimethyldiphenyldisulfitji

Kus 1141 g of p-toluenesulfonyl chloride (6.0 mole) itird with Hafcriumsiilfit in an analogous manner as described in Example · 1, -sin © Tciuolsulf inatlb'sung prepared expected in a 16 liter enamel chair with 925 g of 30 $ acidified hydrochloric acid. After adding 34 g of 57% hydriodic acid (0.15 mol), the kettle is closed and 718 g of sulfur dioxide (11.2 mol) are injected. One hgist the mixture to 100 ⁰ C, whereby the pressure to 6.5 atm stsigt and stirring it for 4 hours. To constant pressure of 5.5 atm by.

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Finally, the batch is cooled and the product as in Example 3 isolated.

The yield is 635 g (86.1 i "of theory), melting point of the crude product is 45 to 47 ⁰ C.

The obtained \ , 4'-dimethyldiphenyl disulfide is chromatographically uniform.

Example I2i

4 , 4 '-Dime thy LcUphenyidisul fid;

The experiment in Example 11 is repeated, but without the addition of hydriodic acid. This time you reduce 8 hours at IO ⁰ O and a maximum pressure of 10 atu. A total of 910 g of aohwefoLdloKid (14.2 mol) are used.

The yield is 620 g (84 % of theory) and the melting point of the crude product is 44 to 46 °.

The 4,4'-dimethyldiphenyl disulfide obtained is chromatographic unity cloth.

Example Ij;

3i 3 '-Ditii trodi pneiiyldioulf id:

572 g of wasaerfeuchtey 3-nitrobenzenesulfinic acid sodium (1.0 mol of 3O, 6 # ige goods; are in a 4 liter enamel Keosel in 2 liters of water. 4ü mol) acidified with 5.6 g of 57 $ strength by weight hydroiodic acid (0.025 mol) was added and the vessel sealed. at room temperature, 160 g of sulfur dioxide pressing anschlieesend (2.5 mol) to the mixture heated to 100 ⁰ C and stirring it at a maximum pressure of 2 atu 1 hour after. After cooling, the disulfide is rubbed as in Example 3, isolated.

The yield is 150.5 g (97 % of theory), the melting point of the crude product is 81 to 82 ^° C.

The 3,3'-dinitrodiphenyl disulfide obtained is chromatographic uniformly.

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Example 14 » / ^

3 ₁ 3'- Dinitrodiphenyldieulfid s The experiment according to Example 13 is repeated, but without the addition of hydriodic acid.

Yield "146 g (94.5 i ° of Theori ^" the melting point of the crude products is 81 to 82 ° C.

The 3,3'-dinitrodiphenyl disulfide obtained is chromatographic uniformly.

Example 15t

3.3'-Dini trodiphenyl disulfide:

Repeating the experiment gemäas Example 13 at a reduction temperature of 6O ⁰ C.

Yield »148.5 g (96.5 % of theory), melting point of the crude product» 82 ^° C.

The 3,3'-dinitrodiphenyl disulfide obtained is chromatographical uniformly.

Example 16;

The experiment according to Example 13 is repeated, but this time sulfur dioxide is used in a large excess. With the addition of 1000 g sulfur (15.6 moles) is reduced for 5 h. At 35 ⁰ C and a pressure of 5 ATU. When the reaction has ended, most of the excess sulfur dioxide is removed under reduced pressure and the solid product is isolated as described in Example 3.

Spoil; 116 g, melting point of the crude product *. 70 to

C.

Example 17s

4,4'-Diaminodiphenyldiaulfide:

1820 g waeserfeuchte 4-acetamido obenzolsulfinsäure (6.6 mole 72.1? Cige goods) are what slurried in a 16 liter enamel kettle in 6 liters. Ser. 34 g of 57 % hydrogen iodide (0.152 mol) binsu, tsraohllslt dec ttattl are added to this suspension, and a pressure of up to 3 parts of sulfur is added.

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dioxide and heats the batch to 100 ⁰ G, the pressure dropping. The pressure is kept at 3 atmospheres by adding more sulfur dioxide and the mixture is stirred for 2 hours until the pressure is constant. A total of 720 g of sulfur dioxide (11.2 mol) are used. The batch is cooled to room temperature, relaxed and the 4,4'-diaminodiphenyl disulfide which has precipitated out as a salt is introduced into excess sodium hydroxide solution into the free base, which is filtered off with suction on a suction filter and washed free of salt with water.

The yield is 742 g (90.8% of theory), the melting point of the crude product is 75 to 76 ^° G.

The 4,4'-diaminodiphenyl disulfide obtained is chromatographic uniformly.

A sample is recrystallized from a benzene / ligroin mixture and then has a melting point of 78 to 79 ° C.

Elemental analysis: calculated (%) found

C. 58.03 57.80 H 4.87 5.10 N 11.28 11.4 S. 25.82. 25.76

Example 18:

4.4'-diaminodiphenyl disulfide:

From 259 g of water-moist 4-acetamidobenzenesulphonic acid chloride, (0.8 mol of 72.1 #ige goods), the corresponding sulphinate solution is prepared with sodium sulphite analogously to Example 1, which is prepared in a 4 liter enamel kettle with 200 g of 30% Acidified hydrochloric acid. The kettle is sealed, pressed at room temperature 128 g SOHW Feldi # © XL4 (2.0 mol) and the mixture heated to 100 ⁰ C. The reaction mixture is stirred for 3 hours at a maximum pressure of 4 atm. at 100 ⁰ C after, it cools down and relaxes the approach. The product is isolated as described in Example 17.

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BATH ORIGINAL.

The expansion is 89.5 g (90.4 1 ° of theory), the melting point of the crude product is 74 to 76 C.

The 4.4 received ^! -Diaminodiphenyl disulfide is chromatographically uniform.

Example 19t

Dinaphthyl-2, 2 '-dlsulfid t

260 g of haphthalene-2-sulfonic acid chloride (1.2 mol) are converted into the corresponding sulfinate with sodium sulfite analogously to Example 1. In a 4 liter enamel kettle, 7.0 g of 57% hydriodic acid (0.031 Mol) ZU ₅ closes the boiler and presses 166 g of sulfur dioxide (2.6 mol) at room temperature. The mixture is heated to 11O ⁰ C and stirred at a Maximaldurck of 4 atm for 3 h., Laughing cooling the mixture, the isolation of the reaction product is carried out as indicated in Example 3.

The yield is 174 g (91.1 $ represents theory), melting point of crude product 136-137 ⁰ C ₀

The dinaphthyl-2 _P 2'-disulfide obtained is chromatographically uniform.

Example 20 ·.

Dinaphthyl-2,2 ^j -disulfide;

The experiment according to Example 19 is repeated, but without the use of hydriodic acid. This time it is reduced at a temperature of 120 ^° C. and a maximum pressure of 5.5 atmospheres.

Yield: 169 g (88.5% of theory), melting point of crude product 136-137 ⁰ Gc

The dinaphthyl-2,2'-disulfide obtained is chromatographic uniform.

Le A 11 922 - 17 -

BATH ORIGINAL 009829/1853

Claims (6)

Iq \ Λ) \ Process for the production of symmetrical DiaryIdisulfiden, characterized in that arylsulfinic acids in an aqueous acidic medium with sulfur dioxide or sulfur dioxide-releasing agents, at temperatures between 0 and + 200, preferably +20 to + 130 ⁰ C without or in the presence of hydroiodic acid or those substances which form hydriodic acid under the reaction conditions, reduced as a catalyst. 2) Method according to claim i), characterized in that one obtained from Aryl3Uifonsäurechloriden by reduction Arylsulfinic acids without intermediate isolation of the latter used as starting substances. 3) Method according to claim l) to 2), characterized in that daaa the reaction in a closed system if necessary under an overpressure of 0 to 10 atmospheres, preferably 1 to 5 atm. 4) Method according to claim 1) to 3) »characterized in that per mole of suifinic acid to be reduced 1.5 to 5.0, preferably 1.5 to 2.5 moles of sulfur dioxide are used. 5) Method according to claim 1) to 4), characterized in that that one per mole of sulfinic acid from 0 to 0.1, preferably from 0 to 0.025 moles of hydriodic acid were used. 6) Method according to claim i) to 5), characterized in that that one in the aqueous solution or suspension of sulfic acid, optionally after addition of the catalyst and if necessary, sulfur dioxide passes in a closed system and the mixture is heated to the reaction temperature. Le A 11 922 - 18 - - 009829/1853 ORIGINAL BATHROOM