Alicyclic hydrocarbons Cycloalkanes

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... 

The enthalpy of fomation of two such species has been measured, namely the cyclopropane and cycloheptane derivatives. The difference between the values for these two species, both as solids, is 238.1 kJmol . Is this difference plausible Consider the difference between the enthalpies of formation of the parent cycloalkanes as solids, 194 kJ mol . The ca 44 kJ mol discrepancy between these two differences seems rather large. However, there are idiosyncracies associated with the enthalpies of formation of compounds with three-membered rings and almost nothing is known at all about the thermochemistry of compounds with seven-membered rings. Rather, we merely note that a seemingly well-defined synthesis of cycloheptyl methyl ketone was shown later to result in a mixture of methyl methylcyclohexyl ketones, and superelectrophilic carbonylation of cycloheptane resulted in the same products as methylcyclohexane, namely esters of 1-methylcyclohexanecarboxylic acid. The difference between the enthalpies of formation of the unsubstituted alicyclic hydrocarbons cycloheptane and methylcyclohexane as solids is 33 kJmol . This alternative structural assignment hereby corrects for most of the above 44 kJ mol discrepancy in the enthalpies of formation of the two oximes. More thermochemical measurements are needed, of oximes and cycloheptanes alike. 

The cycloalkanes also are known as naphthenes, cycloparaffins, or alicyclic hydrocarbons. In the petroleum industry, this class of hydrocarbons is known as naphthenes. Naphthenes have saturated rings. The general formula for the ring without substituents is CnH2n. This is the same as the general formula for the alkene series however, the structural configurations differ completely and, thus, the physical and chemical properties are not at all similar. 

Alicyclic Hydrocarbons. Low-resolution GS or GCMS studies have suggested the presence of alicyclics, such as cycloalkanes (Hayes, 1967) or bicyclics with aliphatic side chains (Kvenvolden et al., 1970 Oro et al., 1971). High-resolution GCMS, however, confirmed only cyclopentene (Studier et al., 1972). An earlier study detected a cyclic terpene. A and/or A" menthene, but it may have been a contaminant (Studier et al., 1968). In any event, the Fischer-Tropsch synthesis readily produces alicyclic hydrocarbons (Weitkamp et al., 1953). 

Other alicyclic hydrocarbons have the same kind of properties as their open-chain counterparts, and they are characterized in the same way cycloalkanes by their general inertness, and cycloalkenes and cycloalkynes by their response to... 

Fischer projection formulas of, 977 Aldotetrose, 974-976 Alicyclic hydrocarbons, 68. See also Cycloalkanes... 

Saturated cyclic hydrocarbons are called cycloalkanes, or alicyclic compounds (aliphatic cyclic). Because cycloalkanes consist of rings of -CH2- units, they have the general formula (CH2) , or and can be represented by polygons... 

Alicyclic (Section 4.1) An aliphatic cyclic hydrocarbon such as a cycloalkane or cycloalkene. 

Cyclic hydrocarbons are called cycloalkanes they are examples of alicyclic (g/ phatic cyclic) compounds. Cycloalkanes, having the general formula are isomeric with alkenes but, unlike... 

These are cyclic alkanes (hydrocarbons) and are also called alicyclic compoimds. Their general formula in CH2n. In these the carbon atoms are linked to form a rings of various sizes. The six membered carbon ring being most commonly found. Most of there cycloalkanes are unreactive to chemical reagents. 

In this chapter we shall take up the alicycUc hydrocarbons (a//phadc cyclic hydrocarbons). Much of the chemistry of cycloalkanes and cycloalkenes we already know, since it is essentially the chemistry of open-chain alkanes and alkenes. But the cyclic nature of some of these compounds confers very special properties on them. It is because of these special properties that, during the past fifteen years, alicyclic chemistry has become what Professor Lloyd Ferguson, of the California State College at Los Angeles, has called the playground for organic chemists. It is on some of these special properties that we shall focus our attention. 

Cycloalkanes are one class of alicyclic (a//phatic cyclic) hydrocarbons. 

Cycloalkanes - Saturated monocyclic hydrocarbons (with or without side chains). See alicyclic compounds. Unsaturated monocyclic hydrocarbons having one endocyclic double or one triple bond are called cycloalkenes and cycloalkynes, respectively. [5]... 

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