Hydrocarbons, alicyclic

Uses The alicyclic hydrocarbons have numerous industrial applications. Cyclopropane (C3H6) is used as an anesthetic. Cyclohexane (CgH ) is used as a chemical intermediate as an organic solvent for oils, fats, waxes, and resins and for the extraction of essential oils in perfume manufacturing industries. Cyclohexene (C6H10) is used in the manufacture of maleic acid, cyclohexane carboxylic acid, and adipic acid. Methyl cyclohexane (C7H14) is used for the production of organic synthetics such as cellulose ethers. These compounds are used in different industries such as adipic acid makers, benzene makers, fat processors, fungicide makers, lacquerers, nylon makers, oil processors, paint removers, plastic molders, resin makers, rubber makers, varnish removers, and wax makers. 

Toxicity Potential symptoms of overexposure to alicyclic hydrocarbons are irritation of eyes and respiratory system, drowsiness, dermatitis, narcosis, and coma. It also causes adverse effects on the CNS of animals and humans. Acute 

The cycloalkanes and cycloalkenes have not received as much attention as the n-alkanes from surface sediments. 

Saturated cyclic hydrocarbons. Debyser et al. (1977) found for sediments from the Baltic, a predominant series of hopanes over the thermodynamic stable series of aj3 hopanes encountered generally in ancient sediments (Ensminger et al., 1974 Van Dorsselaer et al., 1974). The hopane with 31 carbon atoms is present in both series as a uniform C22 isomer, which suggests that the sediment analysed was not polluted with petroleum products which contain equal quantities of the two 22 isomers of the aj3 homohopane (Dastillung and Albrecht, 1976). 

Hopanes (C27—C35) have been recently identified in different recent sediments by Dastillung et al. (1977), Simoneit (1977b), and Dastillung and Corbet (1978). The correlation between the presence of active bacterial populations and the compounds of the hopane type seems to establish the vedue of these as biogeochemical markers. 

The identification of A -sterenes in various recent sediments by Simoneit (1977b) and Dastillung and Albrecht (1977) suggests that these compounds are degradation intermediates of the precursor sterols, via the corresponding stanols. 

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Alicyclic Hydrocarbons. These refer to cyclic analogues of aliphatic hydrocarbons and are named accordingly, using the piefix cyclo-." Their properties are similar to their open-chain aliphatic counterparts. Alicyclic hydrocarbons are subdivided into monocyclic (cycloalkanes, cycloalkenes, cycloalkynes, cycloalkadienes, etc.) and polycyclic aliphatic compounds. Monocyclic aliphatic structures having more than 30 carbon atoms in the ring are known, but those containing 5 or 6 carbon atoms are more commonly found in nature [47, p. 28]. 

Cycloalkanes (ornaphthenes). These are also known as cycloparaffins or saturated alicyclic hydrocarbons." They are quite stable compounds with the general formula with n > 3 for rings without substituent groups. The first two members are... 

Although it is possible to conceive of alicyclic hydrocarbons containing more than a triple bond or two double bonds in the carbocyclic ring, such ring structures are usually either unstable or have transient existence. 

AlsB77 Alspach, B., Aronoff, S. Enumeration of structural isomers in alicyclic hydrocarbons and porphyrins. Canad. J. Chem. 55 (1977) 2773-2777. 

Other common MOCVD compounds are produced from alicyclic hydrocarbons, where the carbon chain forms a ring, such as in... 

The effect of adding large quantities of acetic acid to the medium is more complicated. The acceleration of the oxidation rate of isopropanol was ascribed initially to a shift of the esterification equilibrium to the right (reaction 29). However, RoCek found that acceleration by acetic acid occurs for oxidations which cannot involve a pre-equilibrium esterification, e.g. those of aliphatic and alicyclic hydrocarbons. The obvious alternative, i.e. that acetic acid combines with chromic acid, viz. 

Rios-Harnandez LA, LM Gieg, JM Suflita (2003) Biodegradation of an alicyclic hydrocarbon by a sulfate-reducing enrichment from a gas condensate-contaminated aquifer. Appl Environ Microbiol 69 434-443. 

Stirling LA, RJ Watkinson, IJ Higgins (1977) Microbial metabolism of alicyclic hydrocarbons isolation and properties of a cyclohexane-degrading bacterium. J Gen Microbiol 99 119-125. 

Trudgill PW (1978) Microbial degradation of alicyclic hydrocarbons. In Developments in Biodegradation of Hydrocarbons-1 (Ed RJ Watkinson), pp. 47-84. Applied Science Publishers Ltd, London. 

The reactivity of hydrogens at various positions of aliphatic and alicyclic hydrocarbons and their derivatives in various reactions is successfully interpreted by the theoretical indices, Dr and /r, mentioned in Chap. 6. Most of the results obtained were reviewed in reference 16 and are not repeated here. 

As pointed out previously, controlled degradation reactions are very difficult with aliphatic or alicyclic hydrocarbons, and most of the relabeling work has been concentrated on aromatic reaction products. Procedures have been extensively described by Pines and co-workers (e.g., 97, 96, also 87, 89-98, 95, 98). For the present purpose, it suffices to note that the 14C contents of the methyl side-chains and the rings in aromatic reaction products are readily estimated by oxidation of the methyl to carboxyl, followed by decarboxylation, while ethyl side-chains may be oxidatively degraded one carbon atom at a time. Radiochemical assays may be made on CO2 either directly in a gas counter, or after conversion to barium carbonate, while other solid degradation intermediates (e.g., benzoic acid or the phthalic acids) may be either assayed directly as solids or burned to CO2. Liquids are best assayed after burning to CO2. 

In alicyclic hydrocarbon solvents with aromatic solutes, energy transfer (vide infra) is unimportant and probably all excited solute states are formed on neutralization of solute cations with solute anions, which are formed in the first place by charge migration and scavenging in competition with electron solvent-cation recombination. The yields of naphthalene singlet and triplet excited states at 10 mM concentration solution are comparable and increase in the order cyclopentane, cyclohexane, cyclooctane, and decalin as solvents. Further, the yields of these... 

Peroxyl radicals can undergo various reactions, e.g., hydrogen abstraction, isomerization, decay, and addition to a double bond. Chain propagation in oxidized aliphatic, alkyl-aromatic, alicyclic hydrocarbons, and olefins with weak C—H bonds near the double bond proceeds according to the following reaction as a limiting step of the chain process [2 15] ... 

Alicyclic hydrocarbons are saturated carbon chains that form ring structures. Naturally occurring alicyclic hydrocarbons are common (Chap. 1). For example, alicyclic hydrocarbons are a major component of crude oil, comprising 20-67 vol.%. Other examples of complex, naturally occurring alicyclic hydrocarbons include camphor (a plant terpene) and cyclohexyl fatty acids (components of microbial lipids). Anthropogenic sources of alicyclic hydrocarbons to the environment include fossil-fuel processing and oil spills, as well as the use of such agrochemicals as the pyrethrin insecticides (Chap. 1, and references therein). 

Alicyclic hydrocarbon a hydrocarbon that has a cyclic structure (e.g., cyclohexane) also collectively called naphthenes. 

Unavailable because experimental methods for estimation of this parameter for alicyclic hydrocarbons are lacking in the documented literature... 

Chemical/Physical. Incomplete combustion of propane in the presence of excess hydrogen chloride resulted in a high number of different chlorinated compounds including, but not limited to alkanes, alkenes, monoaromatics, alicyclic hydrocarbons, and polynuclear aromatic hydrocarbons. Without hydrogen chloride, 13 nonchlorinated polynuclear aromatic hydrocarbons were formed (Eklund et al, 1987). 

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