Aliphatic sulphur compounds

A better method involves the interaction of an alkyl bromide and thiourea to form an alkyl iso-thiourea, followed by hydrolysis of the latter with sodium hydroxide solution, for example  

The lower members have remarkably disagreeable odours, but the offensive odour diminishes with increasing carbon content until it almost disappears at about C10H21aSH, n-dodecyl (lauryl) mercaptan. 

The alkyl sulphides or thioethers, the sulphur analogues of the ethers, are conveniently obtained by boiling alkyl halides with anhydrous sodium sulphide 

2C3H7 Br + -Propyl bromide NajS — (C3H7 )2S + n-Propyl sulphide 2NaBr 

2C HlsaBr + n-Hexyl bromide NajS (CgHu jS + n-Hexyl sulphide 2NaBr 

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Aliphatic sulphonic acids, 557 Aliphatic sulphur compounds, 496... 

Heating the Tube.—Place the iron case with its tube in a bomb or tube furnace in such a way that the end with the capillary is raised somewhat and directed towards the wall on which a shield is fixed and close the furnace. Several tubes may be heated simultaneously. Light all the burners and heat gradually to the desired temperature, regulating the gas supply at the main tap. For aliphatic halogen compounds (and many sulphur compounds) this temperature is about 250°, for the aromatic compounds (and sul-phonic acids) it is about 300°. Most substances are completely oxidised after three to four hours, but in the case of aromatic compounds the heating is continued for some hours longer. 

Nitro compounds. Aliphatic nitro compounds are acidic. They are freed from alcohols or alkyl halides by standing for a day with concentrated sulphuric acid, then washed with water, dried with magnesium sulphate followed by calcium sulphate and distilled. The principal impurities are isomeric or homologous nitro compounds. In cases where the nitro compound was originally prepared by vapour phase nitration of the aliphatic hydrocarbon, fractional distillation should separate the nitro compound from the corresponding hydrocarbon. Fractional crystallisation is more effective than fractional distillation if the melting point of the compound is not too low. 

Tricresyl phosphate Hexanes, heptanes, aromatics, organic sulphur compounds and aliphatic chlorides... 

The lower members of the homologous series of 1. Alcohols 2. Aldehydes 3. Ketones 4. Acids 5. Esters 6. Phenols 7. Anhydrides 8. Amines 9. Nitriles 10. Polyhydroxy phenols 1. Polybasic acids and hydro-oxy acids. 2. Glycols, poly-hydric alcohols, polyhydroxy aldehydes and ketones (sugars) 3. Some amides, ammo acids, di-and polyamino compounds, amino alcohols 4. Sulphonic acids 5. Sulphinic acids 6. Salts 1. Acids 2. Phenols 3. Imides 4. Some primary and secondary nitro compounds oximes 5. Mercaptans and thiophenols 6. Sulphonic acids, sulphinic acids, sulphuric acids, and sul-phonamides 7. Some diketones and (3-keto esters 1. Primary amines 2. Secondary aliphatic and aryl-alkyl amines 3. Aliphatic and some aryl-alkyl tertiary amines 4. Hydrazines 1. Unsaturated hydrocarbons 2. Some poly-alkylated aromatic hydrocarbons 3. Alcohols 4. Aldehydes 5. Ketones 6. Esters 7. Anhydrides 8. Ethers and acetals 9. Lactones 10. Acyl halides 1. Saturated aliphatic hydrocarbons Cyclic paraffin hydrocarbons 3. Aromatic hydrocarbons 4. Halogen derivatives of 1, 2 and 3 5. Diaryl ethers 1. Nitro compounds (tertiary) 2. Amides and derivatives of aldehydes and ketones 3. Nitriles 4. Negatively substituted amines 5. Nitroso, azo, hy-drazo, and other intermediate reduction products of nitro com-pounds 6. Sulphones, sul-phonamides of secondary amines, sulphides, sulphates and other Sulphur compounds... 

The simpler aliphatic sulphur derivatives considered in this section are the sulphur analogues of oxygen compounds, e.g. the thiols (RSH), and the symmetrical or unsymmetrical thioethers (R-S-R or R -S-R2). Compounds derived from these two groups, where the sulphur atom can attain a higher oxidation state, are the sulphinic and sulphonic acids (R-SO-OH and R-S02 OH), the sulphox-ides (R-SO-R), and the sulphones (R-S02-R). Other compounds of interest which are considered in the following discussion are ... 

For curing at room temperature, systems based on primary and secondary amines and polyamides are used extensively. More reactive products are obtained with aliphatic chains rather than aromatic amines, which have lower basicity. Sulphur compounds like mercaptans react rapidly with epoxide systems and will provide a basis for rapid-curing—but the bonds resulting tend to be rather brittle and also to have the unpleasant odour of the mercaptan. 

Primary and secondary aliphatic nitro compounds may tautomerise under basic conditions to the salt of the aci isomer. These isomers may in turn be hydrolysed by sulphuric acid, and so result in the fragmentation of the original molecule. Suggest how this reaction might proceed, and what is the final product. 

Nef rearrangement Primary or secondary aliphatic nitro compounds may be hydrolysed to aldehydes or ketones, respectively, by treatment with a base followed by a mild aqueous acid which yields the aci form of the nitro compound. This can then be hydrolysed by concentrated sulphuric acid to give the carbonyl compound. 

Inhibitors which operate mainly on the metal dissolution process would include aromatic and aliphatic amines, various sulphur compounds and carbonyl molecules phosphorus, arsenic and antimony compounds have a greater effect on the hydrogen evolution reaction. Additions to the metal can have a similar effect for example phosphorus is added to some steels to inhibit H2 evolution. 

Aliphatic Organo-sulphur Compounds, Compounds with Exocyclic Sulphur Functional Groups, and their Selenium and Tellurium Analogues... 

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