Hydrocarbon, saturated, preparation

Introduction. It will be recalled that one of the most common methods of distinguishing between aromatic and aliphatic hydrocarbons is the difference in the rates of their reactions with sulfuric acid. Aromatic hydrocarbons readily form sulfonic acids when heated with concentrated sulfuric acid at temperatures varying from 80 to 200 . Saturated paraffin hydrocarbons, on the other hand, do not react with sulfuric acid under comparable conditions. A number of saturated paraffins are sulfonated directly by using fuming sulfuric acid and heating under pressure, but the sulfonic acids of the lower paraffin hydrocarbons are prepared by reacting alkyl halides with alkali sulfites. The sulfonic acids of the aromatic hydrocarbons are of much greater importance than the sulfonic acids of paraffins. 

Figure 3b. Hydrocarbons from a water-soluble fraction of a biological bioassay solution (satured hydrocarbons lost) prepared from a South Louisiana crude oil. Chromatograph conditions Stainless column (91 m X 0.25 mm) wall coated with low viscosity DC-200. Gas sample containing hydrocarbons collected from sample loop on head of column at —100°C, quickly raised to 20°C, and temperature programmed...

Chemical methods may be employed if the reagent attacks only one of the components. Thus quicklime may be employed for the removal of water in the preparation of absolute ethyl alcohol. Also aromatic and unsaturated hydrocarbons may be removed from mixtures with saturated hydrocarbons by sulphonation. 

The superacid-catalyzed electrophile oxygenation of saturated hydrocarbons, including methane with hydrogen peroxide (via H302 ) or ozone (via HOs ), allowed the efficient preparation of oxygenated derivatives. 

Silane, pure or doped, is used to prepare semiconducting siUcon by thermal decomposition at >600° C. Gaseous dopants such as germane, arsine, or diborane maybe added to the silane at very low concentrations in the epitaxial growing of semiconducting siUcon for the electronics industry. Higher silanes, eg, Si H and Si Hg, are known but are less stable than SiH. These are analogues of lower saturated hydrocarbons. 

Organoperoxysulfonic acids and their salts have been prepared by the reaction of arenesulfonyl chlorides with calcium, silver, or sodium peroxide treatment of metal salts of organosulfonic acids with hydrogen peroxide hydrolysis of di(organosulfonyl) peroxides, RS(0)2—OO—S(02)R, with hydrogen peroxide and sulfoxidation of saturated, non aromatic hydrocarbons, eg, cyclohexane (44,181). 

The reduction of tosylhydrazones by complex metal hydrides has been used very effectively to prepare saturated steroid hydrocarbons in high yields. ... 

An interesting PLC variation of the nrea clathration techniqne has been proposed by Chaffee and Johns [82]. Component mixtnres are applied onto TLC plates (20 cm X 20 cm X 0.5 mm) coated with Kieselgnhr G/nrea (2 1), prepared from a slnrry in urea-saturated methanol (Iml/g powder). Spotted plates are left in methanolic atmosphere overnight to allow clathrate formation. To remove methanol, plates are air dried for 2 to 3 h at room temperatnre and then developed in -heptane. Two bands of acychc (Rf 0.9 to 1.0) and cyclic (Rf 0.0 to 0.1) hydrocarbons are distinguished, and components are recovered qnantitatively by extraction with chloroform. 

SFC has played an important role in the extraction and isolation of fatty acids [355,356]. Underivatised fatty acids and methyl esters of fatty acids are surprisingly easy to elute using a bonded phase or a silica based packed column and pure C02, probably due to the long hydrocarbon tails on the molecules [357]. On the other hand, most aromatic and polysubstituted acids will not elute. Triglycerides with saturated fatty acids can be analysed faster with pSCF-ELSD than with GC-FID and do not require sample preparation [358]. Using... 

On-line SFE-pSFC-FTD, using formic or acetic acid modified CO2 as an extraction solvent, was used to analyse a dialkyltin mercaptide stabiliser in rigid PVC (Geon 87444) [114]. Hunt et al. [115] reported off-line SFE-pSFC-UV analysis of PVC/(DIOP, chlorinated PE wax, Topanol CA), using methanol as a modifier. Individual additives are unevenly extracted at lower pressures and temperatures, where extraction is incomplete. Topanol CA, the most polar of the three PVC additives studied, could not be fully extracted in the time-scale required (15-20min), even at the highest CO2 temperature and pressure obtainable. However, methanol-modified CO2 enhances extraction of Topanol CA. PVC film additives (DEHP, fatty acids, saturated and aromatic hydrocarbons) were also separated by off-line SFE-preparative SFC, and analysed by PDA and IR [116]. 

A number of alkylperoxy Co111 complexes including mainly polyimine ligands have been prepared, exemplified by (223).979 Hydroxylation of saturated hydrocarbons, preferentially at the more nucleophilic C—H bonds, yields alcohols, ketones, and t-butylperoxo products, whereas olefins form epoxides if they carry no allylic H atoms. 

The pulse technique may also be conveniently extended to include stages of reactant preparation. Figure 9 shows a schematic representation of a pulse reactor system recently used by Gault et al. (81), which includes stages for alcohol (the reactant precursor) dehydration and subsequent olefin hydrogenation, the resulting saturated hydrocarbon being the material of catalytic interest. A method has been described (82) which allows the use of a pulse reactor at above atmospheric pressure. 

Akiyoshi, M., Deguchi, T., Sanemasa, I. (1987) The vapor saturation method for preparing aqueous solutions of solid aromatic hydrocarbons. Bull. Chem. Soc. Jpn. 60, 3935-3939. 

The reaction described is of considerable general utility for the preparation of benzoyloxy derivatives of unsaturated hydrocarbons.2"8 Reactions of 2-butyl perbenzoate with various other classes of compounds in the presence of catalytic amounts of copper ions produce benzoyloxy derivatives. Thus this reaction can also be used to effect one-step oxidation of saturated hydrocarbons,9, 10 esters,6,11 dialkyl and aryl alkyl ethers,12 14 benzylic ethers,11,15 cyclic ethers,13,16 straight-chain and benzylic sulfides,12, 17-19 cyclic sulfides,11,19 amides,11 and certain organo-silicon compounds.20... 

Mercuric oxide (5 g.) is dissolved for the most part in a still warm mixture of 110 c.c. of water and 50 c.c. of concentrated sulphuric acid. The mixture is brought into a large hydrogenation flask (Fig. 58, p. 377) and shaken for some time with acetylene prepared from calcium carbide, purified with acid solutions of dichromate and copper nitrate, and collected over saturated sodium chloride solution in a glass gas-holder (capacity 10-15 litres). Before shaking is begun the air present must be displaced by the hydrocarbon. 

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