Hydrogen sulphide, pyrolysis

Shock-tube experiments on the decomposition of hydrogen sulphide have been performed but were unsuccessful because traces of oxygen and other oxidizers could not be removed from the reactant24. No data are available on the homogeneous decomposition of hydrogen polysulphides, nor have the kinetics of pyrolysis of selenium and tellurium hydrides been studied. 

In the pyrolysis of proteins, the dominant mechanism is the splitting-off of the amino acids rather than break-up of the backbone into smaller fragments which are characteristic of the original amino acids.Usually highly characteristic signals are found for the aromatic and sulphur containing amino acids, e.g., hydrogen sulphide from cystine and in combination with methionine pyrrole pyrrolidine and methylpyrrole for proline, phenyl, and cresol from tyrosine, toluene, styrene and phenylacetonitrile for phenylalanine indole, and methylindol from tryptophan. 

The sulphurdi-imines are hydrolysed in acidic media to sulphur dioxide and two equivalents of amine. Oxidation with ozone afforded a nitrocompound and sulphinylamine. Pyrolysis of the diphenyl derivative (100 R = Ph) gave azobenzene, but pyrolysis of the di-t-butyl derivative (100 R = t-butyl) resulted in an intramolecular elimination to isobutylene, hydrogen sulphide, and ammonia. The bis-tosyl imine (100 R = toluene-p-sulphonyl) reacted with diamines (1,2----------1,6-) in an... 

The main purpose of this article is to present a survey of the results, which have been obtained in our laboratories and by other researchers, on the pyrolysis of light alkcuies from to C5, around 500 C, in the presence of three hydrogenated additives hydrogen chloride, HCl, hydrogen bromide, HBr, hydrogen sulphide, H S the thermal decompositions have been performed at relatively small extents of reaction. 

It has also been shown that hydrogen sulphide has a strong inhibiting influence upon the pyrolysis of ethane (6, H,). This effect of hydrogen sulphide upon the formation of the major products of ethane pyrolysis has also been observed by Me LEAN and Me KENNEY in 1970 (U). 

In a simulation of the reaction of glucose and cellulose with hydrogen sulphide and polysulphide at ambient temperature in aqueous solution the formation of organic sulphur compounds was observed which yielded thiophene on pyrolysis/evaporation. By such a process carbohydrates in nature might be converted into sulphur compound which, being resistant to microbial attack, would be preserved in sediments. ... 

Selective catalytic hydrogenation of dienes and polyenes to monoenes over nickel sulphide supported on alumina or silica finds application in the partial hydrogenation of soybean oil and isoprene in the presence of methylbutenes. A sulphided C0-W/AI2O3 catalyst has been proposed for the selective hydrogenation of dienes in pyrolysis gasoline. 

Pyrolysis curves of lead derivatives. 9) Sulphide. 10) Sulphl 11) Hydrogen phosphate. 12) Carbonate. 13) Basic thiocyanate. 14) Oxalate. 15) Phthalate. Reproduced from C. Duval, "Thermo-gravimetric Analysis". Elsevier Publishing Co., Amsterdam (1953) p. 466. 

---