Unsaturated aliphatic hydrocarbons, determination

Ultrapure waters, determination of organic compounds 137 Unsaturated aliphatic hydrocarbons, determination of 283-288 Uranium, determination of 47,157, 230,231... 

Chakactkrisation of Unsaturatkd Aliphatic Hydrocarbons Unlike the saturated hydrocarbons, unsaturated aliphatic hydrocarbons are soluble in concentrated sulphuric acid and exhibit characteristic reactions with dUute potassium permanganate solution and with bromine. Nevertheless, no satisfactory derivatives have yet been developed for these hydrocarbons, and their characterisation must therefore be based upon a determination of their physical properties (boiling point, density and refractive index). The physical properties of a number of selected unsaturated hydrocarbons are collected in Table 111,11. 

Considerable attention has been directed in determining the products from reactions of aliphatic hydrocarbons, aromatic compounds, and unsaturated compounds including biogenic terpenes that exhibit appreciable volatility. These studies have been conducted both in simulation chambers and using natural sunlight in the presence of NO. 

There has been a growing interest in applying high performance liquid chromatography, to the determination of the not only volatile compounds, such as aliphatic and polyaromatic hydrocarbons, saturated and unsaturated aliphatic and polyaromatic hydrocarbons, saturated and unsaturated aliphatic halogen compounds, haloforms and some esters, phenols and others but also non volatile components of water. 

Based on elemental composition and relative molecular mass determinations, the formula of benzene was found to be C6H6. The saturated hydrocarbon hexane has the molecular formula C6H14 and therefore it was concluded that benzene was unsaturated. Kekule in 1865 proposed the cyclic structure 4 for benzene in which the carbon atoms were joined by alternate single and double bonds. Certain reactions of benzene, such as the catalytic hydrogenation to cyclohexane, which involves the addition of six hydrogen atoms, confirmed that benzene was a ring compound and that it contained three double bonds. However, since benzene did not undergo addition reactions with HC1 and HBr, it was concluded that these double bonds were different from those in ethene and other unsaturated aliphatic compounds. 

The terpenes and their derivatives have been carefully studied in an endeavor to determine the relation which exists between the structural configurations of these important substances. Some of the hydrocarbons are unsaturated aliphatic compounds to this class belong isoprene, CsHg (48), which is called a hemiter-pene, and anhydrogeraniol,... 

The photoionisation detector (PID) is used for the selective determination of aromatic hydrocarbons and unsaturated compounds such as aliphatics, aromatics, ketones, esters, aldehydes, amines, heterocyclics and some organometallics. It is relatively insensitive to saturated hydrocarbons and halocarbons. This device uses ultraviolet light as a means of ionising the analytes exiting the GC column and the ions produced by this process... 

The weakest bond in a polymer chain determines the overall thermal stability of the polymer molecule. The aliphatic carbon-carbon bond has a relatively low bond energy (see Table 5.1). Oxidation of alkylene groups is also observed during prolonged heating in air. Thus the weak links to be avoided are mostly those present in alkylene, alicyclic, unsaturated, and nonaromatic hydrocarbons. On the other hand, the functions proven to be desirable are aromatic (benzenoid or heterocyclic) ether, sulfone, and some carboxylic acid derivatives (amide, imide, etc.). Aromatic rings in the polymer chain also give intrinsically stiff backbone. 

The aqueous phase can be either a condensate, such as exists in fuel product pipelines, or it can contain moderate amounts of solids, such as is the case in refinery crude distillation overheads, or it can be strong brine, as in the aqueous phase produced in an oil well. The hydrocarbon phase can vary among aromatic, aliphatic, saturated, and unsaturated compounds, all of which can affect the solubility and the effectiveness of the inhibitor. Both fluids may be saturated with gases, such as carbon dioxide, hydrogen sulfide or air that will be factors in determining corrosiveness and the requirements of the inhibitor. Temperatures may range between ambient and 205 °C (400 °F). 

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