Sulphur in benzene

Tetra-aryldiarsines when boiled with a suspension of sulphur in benzene solution yield diarylarsenious sulphides, but an excess of sulphur may result in the formation of an arylarseniousrfesquisulphide,... 

Dlnitrodiphenylarsenious sulphide, [(N02.CgH4)2As]2S, results when a slight excess of tetranitrotetraphenyldiarsine is boiled with a suspension of sulphur in benzene. It forms warty aggregates of yellow needles, M.pt. 156° C. When an excess of sulphur is used, tetranitrotetraphenyldiarsemoustrisulpMde, C, Oi), is formed as a yellow powder, M.pt. 69° C. 

The first synthesis of an optically active tertiary arsine sulphide from an optically active tertiary arsine was reported in 1962 , compounds 157 and 158 being prepared by heating the respective optically active tertiary arsines with sulphur in benzene. Along similar lines, arsine sulphides 136,159-164 were prepared and isolated (Table 8). The sulphurization of the tertiary arsines occurs with retention of configuration at arsenic. 

Miscellaneous. The unusual reductions of benzyltriphenylphosphonium salts with sodium to give benzyldiphenylphosphine have been shown to involve reduction of the benzylidenephosphorane. This ylide with sulphur in benzene at 70 °C gave triphenylphosphine sulphide, a pentasulphide formulated as (45) or (46), and only traces of isomeric stilbenes. Previous workers reported high yields of stilbenes from the same reaction carried out in refluxing toluene. Benzoylmethylenetriphenylphosphorane (47) with sulphur gave a polymer of the thioaldehyde (48). 

Condensation of methyl o<-D-glucopyranoside with tris(diethyl)phos-phamide and sulphur in benzene-ether gave two diastereoisomeric thio-phosphates (54-) and the thiophosphates (55) and (56)." ... 

CAUTION. The preparation of o-nitrobenzoyl chloride, o-nitrophenacetyl chloride and all o nitroacid chlorides should not be attempted by the above methods a violent explosion may occur upon distilling the product or when the last traces of thionyl chloride are removed in vacuo at 100°. Perhaps the safest method is to treat the pure acid in benzene solution with 1 1 mols of thionyl chloride and to reflux until evolution of sulphur dioxide and hydrogen chloride has ceased the solution of the acid chloride in benzene may then bo employed for most reactions. 

Table 9.7 contains recent data on the nitration of polychlorobenzenes in sulphuric acid. The data continue the development seen with the diehlorobenzenes. The introduetion of more substituents into these deactivated systems has a smaller effect than predicted. Whereas the -position in ehlorobenzene is four times less reactive than a position in benzene, the remaining position in pentachlorobenzene is about four times more reactive than a position in 1,3,4,5-tetraehlorobenzene. The chloro substituent thus activates nitration, a circumstance recalling the faet that o-chloronitrobenzene is more reactive than nitrobenzene. As can be seen from table 9.7, the additivity prineiple does not work very well with these compounds, underestimating the rate of reaction of pentachlorobenzene by a factor of nearly 250, though the failure is not so marked in the other cases, especially viewed in the circumstance of the wide range of reactivities covered. 

Pilocarpine dissolves in dilute soda solution, and the rotation is thereby reduced, due to the formation of the sodium salt of pilocarpic acid, CiiHigOgNa, of which pilocarpine is the lactone. Amorphous barium and copper salts have been prepared. Pilocarpine in dilute sulphuric acid gives with hydrogen peroxide, followed by potassium dichromate, a bluish-violet colour soluble in benzene. For the identification of the alkaloid Wagenaar recommends precipitation with gold chloride solution. 

Kinetic studies with benzene in acetic anhydride containing 0.4-2 M nitric acid at 25 °C show the reaction to be first-order in benzene and approximately second-order in nitric acid this falls to first-order in nitric acid on addition of sulphuric acid, which also increases the first-order rate coefficient (first-order in benzene) from 4.5 x 10-4 to 6.1 x 10 4. By contrast the addition of as little as 0.001 M sodium nitrate reduced the rate to 0.9 x 10-4 without affecting the kinetic order70. These results were, therefore, interpreted as nitration by nitronium ion via equilibria (21a) and (22). 

Kinetic studies of alkene-phosphorus pentachloride reactions in benzene show the effects of substituents when the double bond is terminal.88 When the alkene is conjugated, the standard work-up conditions (using sulphur dioxide) produce alk-1-enylphosphonyl dichlorides (103), instead of 2-chloroalkylphosphonyl dichlorides (104).87... 

In 1976 he was appointed to Associate Professor for Technical Chemistry at the University Hannover. His research group experimentally investigated the interrelation of adsorption, transfer processes and chemical reaction in bubble columns by means of various model reactions a) the formation of tertiary-butanol from isobutene in the presence of sulphuric acid as a catalyst b) the absorption and interphase mass transfer of CO2 in the presence and absence of the enzyme carboanhydrase c) chlorination of toluene d) Fischer-Tropsch synthesis. Based on these data, the processes were mathematically modelled Fluid dynamic properties in Fischer-Tropsch Slurry Reactors were evaluated and mass transfer limitation of the process was proved. In addition, the solubiHties of oxygen and CO2 in various aqueous solutions and those of chlorine in benzene and toluene were determined. Within the framework of development of a process for reconditioning of nuclear fuel wastes the kinetics of the denitration of efQuents with formic acid was investigated. 

These substances are insoluble in benzene and hence easily removable from tetryl by crystallization in this solvent. They are fine-crystalline products of a yellowish colour. They increase with the amount of water contained in the nitrating acid. Michler and Pattison [19] proved that N-tetramethylbenzidine is formed by heating dimethylaniline with sulphuric acid. 

Nitrogen sulphide, N4S4, m.p. 178°C, was prepared by Soubeiran [115] by the action of ammonia on sulphur chloride dissolved in benzene... 

By submitting various metallic sulphides, e.g. those of bismuth, silver, cadmium or zinc, to the action of a solution of sulphur chloride in benzene or toluene, a greenish-blue precipitate of sulphur is obtainable, but the product invariably contains several units per cent, of mineral impurity.2 The suggestion that Ultramarine owes its colour to the presence of a blue variety of sulphur appeal s to have little probability, especially in view of the stability of this substance towards heat,4 and indeed the true nature of the blue- or green-coloured precipitates of sulphur, obtained by any of the afore-mentioned methods, requires much more experimental investigation before the existence of a blue or green modification of sulphur can be accepted. 

Sulphur dissolves in the various hydrogen polysulphides as already described 3 the solutions deposit crystalline sulphur when cooled or on the addition of benzene.4 As solutions of sulphur in hydrogen disulphide or trisulphide behave in this way, whereas the fresh crude polysulphidc does not yield its excess of sulphur on similar treatment, this supplies further evidence of the existence of a higher polysulphide in the crude persulphide. ... 

Physical Properties.—Sulphuryl chloride is a colourless, fuming liquid, with an extremely pungent odour. Z)2 = 1-6074 ->t " = l-4437. It boils at 69-1° C. at 760 mm. pressure, and freezes at —46° C.5 The vapour density is normal at first, but when the chloride is kept, even at 100° C., its vapour commences to dissociate into sulphur dioxide and chlorine. At 200° C. dissociation is almost complete.6 When dissolved in benzene the substance shows a molecular- weight corresponding with S02C12. At ordinary temperatures the specific heat is 0-233, the latent heat of evaporation 32-4 calories per gram, and the heat of formation from the elements approximately 89,540 calories per gram-molecule.7 The dielectric constant at 20° C. is 8-5. As a solvent, the ebullioscopic constant of sulphuryl chloride has been found to have... 

Ammonia is slowly absorbed by the triiodide and a voluminous yellow substance is produced8 which, if kept over sulphuric acid, loses ammonia until the composition corresponds with the tetrammino-triiodide, AsIg.ANHg. At 0° C. more ammonia can be absorbed to yield the dodecammino-compound, AsI3.12NH3. If ammonia is passed into a solution of the triiodide in benzene or ether, a voluminous white precipitate, of composition 2AsI3.9NH3, is formed.8 The existence of these ammines as definite compounds has not been established.10 With phosphine, arsenic phosphide is produced ... 

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