Aliphatic hydrocarbons, determination

Aliphatic halogen compounds, determination of 282,283,350,35h 369 Aliphatic hydrocarbons, determination of 273-275 Alkali earths, determination of 40,43, 46, 47,91-94... 

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. 

The observations discussed above suggest that the kinetic order of lithium poly-isoprene propagation should vary with the living polymer concentration. The effect is imperceptible in aliphatic hydrocarbons, but is observed in benzene solutions. The apparent propagation constants of lithium polyisoprene (MW 2 2 10 ) were determined in benzene and the results are displayed in Fig. 16 in the form of a plot of log kapp vs log c, c denoting the total living polymer concentration. 

Chemical vapor deposition (CVD) of carbon from propane is the main reaction in the fabrication of the C/C composites [1,2] and the C-SiC functionally graded material [3,4,5]. The carbon deposition rate from propane is high compared with those from other aliphatic hydrocarbons [4]. Propane is rapidly decomposed in the gas phase and various hydrocarbons are formed independently of the film growth in the CVD reactor. The propane concentration distribution is determined by the gas-phase kinetics. The gas-phase reaction model, in addition to the film growth reaction model, is required for the numerical simulation of the CVD reactor for designing and controlling purposes. Therefore, a compact gas-phase reaction model is preferred. The authors proposed the procedure to reduce an elementary reaction model consisting of hundreds of reactions to a compact model objectively [6]. In this study, the procedure is applied to propane pyrolysis for carbon CVD and a compact gas-phase reaction model is built by the proposed procedure and the kinetic parameters are determined from the experimental results. 

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. 

Grob and Zurcher [36,53-55] have carried out very detailed and systematic studies of the closed loop gas stripping procedure and applied it to the determination of parts per billion of 1-chloroalkanes in water. Westerdorf [56] applied the technique to chlorinated organics and aromatic and aliphatic hydrocarbons. 

Other workers have discussed the application of dynamic headspace analysis to the determination of aliphatic hydrocarbons in seawater [14-18]. 

Grob et al. [220-223] have carried out very detailed and systematic studies of the closed-loop gas stripping procedure and applied it to the determination of xg/l of 1-chloroalkanes in water. Westerdorf [224] applied the technique to chlorinated organics, and aromatic and aliphatic hydrocarbons. Waggot and Reid [225] reported that a factor of major concern in adapting the technique to more polluted samples is the capacity of the carbon filter, which usually contains only 1.5-2 mg carbon. They showed that the absolute capacity of such a filter for a homologous series of 1-chloro-n-alkanes was 6 xg for complete recovery. 

Partition coefficients of a series of aliphatic hydrocarbons, including n-hexane, have been determined in human tissues (Perbellini et al. 1985). The following partition coefficients for n-hexane (olive oil/air, blood/air, tissue/air) were determined olive oil, 146 blood, 0.80 liver, 5.2 kidney, 3 brain, 5 fat, 104 muscle, 5 heart, 2.8 and lung, 1. Saline/air partition was not reported separately for n-hexane, but was very low for the range reported for the entire group of compounds (0.1-0.4). 

Crebelli, R., Andreoli, C., Carere, A., Conti, L., Crochi, B., Cotta-Ramusino, M., Benigni, R. Toxicology of halogenated aliphatic hydrocarbons Structural and molecular determinants for the disturbance of chromosome segregation and the induction of lipid peroxidation. Chem. Biol. Interact. 1995, 98, 113-129. 

Spectrofluorimetric methods are applicable to the determination of aliphatic hydrocarbons, and humic and fulvic acids in soil, aliphatic hydrocarbons polyaromatic hydrocarbons, optical whiteners, and selenium in non-saline sediments, aliphatic aromatic and polyaromatic hydrocarbons and humic and fulvic acids in saline sediments. The only application found in luminescence spectroscopy is the determination of polychlorobiphenyl in soil. Generally speaking, concentrations down to the picogram (pg L 1), level can be determined by this technique with recovery efficiencies near f00%. 

Infrared spectroscopy has been applied to the determination of particulate organic carbon in non-saline sediments, aliphatic hydrocarbons and total organic carbon in saline sediments and mixtures of organics in sludges. 

Despite the advances made in high-performance liquid chromatography in recent years, there are still occasionally applications in which conventional column chromatography is employed. These methods lack the sensitivity, resolution and automation of HPLC. They include the determination of urea herbicides in soil, polyaromatic hydrocarbons, carbohydrates, chloroaliphatic compounds and humic and fulvic acids in non-saline sediments. The technique has also been applied in sludge analysis, e.g. aliphatic hydrocarbons and carboxylic acids. 

Concawe [8] have described a method for the determination of aliphatic hydrocarbons in soil based on carbon tetrachloride extraction followed by infrared spectroscopy or gas chromatography. 

Page et al. [21] used capillary gas chromatography and capillary gas chromatography-mass spectrometry to determine aliphatic hydrocarbons in interstitial sediments collected on the French coastline following the Amoco Cadiz disaster. 

In a method described by Ryzhova et al. [30] for the determination of aliphatic hydrocarbons in wastewater sludges the hydrocarbons were extracted from sludge using a mixture of pentane and hexane. Metal salts... 

The Curie Point flash evaporation-pyrolysis gas chromatography-mass spectrometric method [32] described in section 2.2.1.2 for the analysis of aliphatic hydrocarbons in soils has also been applied to the determination of polyaromatic hydrocarbons (see Table 2.1). Table 2.2 lists the polyaromatic hydrocarbon contents found by this method in a soil sample. 

Methods have been described for determining chlorinated aliphatic hydrocarbons in soil and chemical waste disposal site samples. The latter method involves a simple hexane extraction and temperature programmed gas chromatographic analysis using electron capture detection and high resolution glass capillary columns. Combined gas chromatography-mass spectrometry was used to confirm the presence of the chlorocarbons in the samples [4],... 

The benzene-water extraction gas chromatographic procedure described in section 2.1.1.1 for the determination of aliphatic hydrocarbons in soil has also been applied to the determination of polychlorinated dibenzo-p-dioxins in soil [73],... 

The flash evaporation pyrolysis gas chromatography method [16] as described in section 11.1.4 for the determination of polycyclic aromatic hydrocarbons, haloorganics, aliphatic hydrocarbons, heteroaromatics, elemental sulphur and pyrolysis products of synthetic polymers in soils has also been applied to non-saline sediments. 

Isobutene is one of the very small number of aliphatic hydrocarbons which form linear high polymers by cationic catalysis (see Section 5). The reason for this is that only in these few among the lower aliphatic olefins is there found the right balance of those factors which determine the path of a cationic polymerisation. For the formation of linear high polymers it is necessary that the propagation reaction should be much faster than all alternative reactions of the growing end of the chain and for any appreciable numbers of chains to be formed at all, the initiation must be fast. ... 

Levsen, K. Heimbrecht, J. Isomerization of Hydrocarbon Ions. VI. Parameters Determining the Isomerization of Aliphatic Hydrocarbon Ions. Org. Mass Spectrom. 1977,72, 131-135. 

Bureau Intemational Technique des Solvants Chlores. 1976. Standardizations of methods for the determination of traces of some volatile chlorinated aliphatic hydrocarbons in air and water by gas chromatography. Anal Chim Acta 82 1-17. 

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