Aliphatic hydrocarbons, monocyclic

Monocyclic Aliphatic Hydrocarbons. Monocyclic aliphatic hydrocarbons (with no side chains) are named by prefixing cyclo- to the name of the corresponding open-chain hydrocarbon having the same number of carbon atoms as the ring. Radicals are formed as with the alkanes, alkenes, and alkynes. Examples ... 

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]. 

Mixtures of gaseous or liquid hydrocarbons which can be vaporized represent the raw materials preferable for the industrial production of carbon black. Since aliphatic hydrocarbons give lower yields than aromatic hydrocarbons, the latter are primarily used. The best yields are given by unsubstituted polynuclear compounds with 3-4 rings. Certain fractions of coal tar oils and petrochemical oils from petroleum refinement or the production of ethylene from naphtha (aromatic concentrates and pyrolysis oils) are materials rich in these compounds. These aromatic oils, which are mixtures of a variety of substances, are the most important feedstocks today. Oil on a petrochemical basis is predominant. A typical petrochemical oil consists of 10-15% monocyclic, 50-60% bicyclic, 25-35% tricyclic, and 5-10% tetracyclic aroma tes. 

The acyclic aliphatic hydrocarbons have the general formula CnH2n + 2 cyclic saturated hydrocarbons (alicyclic hydrocarbons) have the general formula CnH2n (if monocyclic), CnH2n 2 (if bicyclic), etc. The structures of these hydrocarbons may be represented in the chemical literature in various ways some common conventions which are used freely in texts are illustrated here. 

Callahan, M.A., Slimak, M.W., Gabel, N.W., May, I.P, Fowler, C.F., Freed, J.R., Jennings, P., Durfee, R.L., Whitemore, F.C., Maestri, B., Mabey, W.R., Holt, B.R., Gould, C. (1979) Water-Related Environmental Fate of 129 Priority Pollutants. Vol.II, Halogenated aliphatic hydrocarbons, halogenated ethers, monocyclic aromatics, phthalate esters, polycyclic aromatic hydrocarbons, nitrosoamines and miscellaneous compounds. LPAH40/4-79-029b. 

EPA. 1979. Water-related environmental fate of 129 priority pollutants. Vol. II Halogenated aliphatic hydrocarbons, halogenated ethers, monocyclic aromatics, phthalate esters, polycyclic aromatic hydrocarbons, nitrosamines, miscellaneous compounds. U.S. Environmental Protection Agency, Washington, DC. EPA-440/4-79-029B. 

Table 2 Aliphatic and monocyclic saturated hydrocarbons in the molecular fossil record and their paleobiological interpretation. 

Petroleum hydrocarbons contain a wide range of substances that are potential health hazards. These include aliphatic compounds, monocyclic aromatics, polycyclic aromatics, and heavy metals. Most petroleum products have an objectionable taste and odor well below the level that might induce chronic toxicity in humans. Thus, the most frequently reported symptoms of exposure are relatively mild and include nausea, vomiting, and diarrhea. 

It has generally been concluded that the carboxylic acids in petroleum with less than eight carbon atoms per molecule are almost entirely aliphatic in nature monocyclic acids begin at C6 and predominate above CM. This indicates that the structures of the carboxylic acids correspond with those of the hydrocarbons with which they are associated in the crude oil. Thus, in the range where paraffins are the prevailing type of hydrocarbon, the aliphatic acids may be expected to predominate similarly, in the ranges where the monocycloparaffins and dicycloparaffins prevail, one may expect to find principally monocyclic and dicyclic acids, respectively. 

These may occur in water, sediment, or air samples, and several procedures have been used for analytes including halogenated aliphatic compounds, low-molecular-weight aliphatic ethers such as f-butyl methyl ether, and monocyclic aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylenes (BTEX). 

The kinetics of the reactions of many xenobiotics with hydroxyl and nitrate radicals have been examined under simulated atmospheric conditions and include (1) aliphatic and aromatic hydrocarbons (Tuazon et al. 1986) and substituted monocyclic aromatic compounds (Atkinson et al. 1987c) (2) terpenes (Atkinson et al. 1985a) (3) amines (Atkinson et al. 1987a) (4) heterocyclic compounds (Atkinson et al. 1985b) and (5) chlorinated aromatic hydrocarbons (Kwok et al. 1995). For PCBs (Anderson and Hites 1996), rate constants were highly dependent on the number of chlorine atoms, and calculated atmospheric lifetimes varied from 2 days for 3-chlorobiphenyl to 34 days for 2,2, 3,5, 6-pentachlorbiphenyl. It was estimated that loss by hydroxylation in the atmosphere was a primary process for removal of PCBs from the environment. It was later shown that the products were chlorinated benzoic acids produced by initial reaction with a... 

The products from the oxidation of alkylbenzenes under simulated atmospheric conditions have been noted earlier. Both ring epoxides that were highly functionalized and aliphatic epoxides from ring fission were tentatively identified (Yu and Jeffries 1997), and formation of the latter, many of which are mutagenic, may cause further concern over transformation products from monocyclic aromatic hydrocarbons in the atmosphere. 

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