Hydrocarbons of the Methane Series

Classification of Hydrocarbons.- -In a systematic study of the compounds of carbon it is advisable to begin with a consideration of the compounds which contain hydrogen and carbon only. These substances, which are called hydrocarbons, occur in nature, are formed in certain industrial processes, and have important uses. It is not for these reasons, however, that the hydrocarbons are first studied. They are, perhaps, the simplest organic compounds, and a knowledge of their properties and reactions is the best preparation for the study of more complex substances. Further, most compounds can be considered as derived from the hydrocarbons by the replacement of one or more hydrogen atoms by other atoms or groups of atoms. 

One more example will be given. There are a number of important hydrocarbons which form characteristic compounds when they are treated with sulphuric acid or with nitric acid. Benzene, CeHe, toluene, CvHg, and xylene, CsHio, are examples. The general formula for these hydrocarbons is CnH2n-6. 

Methane, CH4, the first member of the paraffin series, is the only hydrocarbon which contains but one carbon atom. It is a colorless and odorless gas, slightly soluble in water, and has the specific gravity 0.559 compared with air. Its molecular weight is less than that of any other compound, and it is, consequently, the lightest compound gas known. Liquid methane boils at —165° and solidifies at —184°. 

Other natural processes bring about the formation of this hydrocarbon. The intestinal gases which are formed as the result of the imperfect digestion of foods contain at times as much as 56 per cent of methane. The compound occurs in coal mines, and on account of the fact that it burns it is called by miners fire-damp its presence in coal mines often leads to 

Natural gas contains about 90 per cent methane. The method of the formation within the earth of large quantities of methane has aroused the interest of chemists. Some hold the view that the gas is formed as the result of the action of heat on vegetable substances, while -others are of the opinion that animal remains are the source of the gas. The subject will be discussed more fully when the theories as to the formation of petroleum are considered (28). 

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GrenzflSjchen-erscheinung, /. interfacial phenomenon, -katalyse, /, contact catalysis, -spannung, /. interfacial tension. Grenz-gesetz, n. limit law (one which natural phenomena approximate but never actually fulfill), -kohlenwasserstoff, m, any hydrocarbon of the methane series, alkane, paraffin, limit hydrocarbon, -kurve,/, limiting curve, limit curve, -last, /. limit ioad, maximum load, -leistung, /, peak performance, maxi-... 

Alkyl derivatives of these cyanate compounds in which the alkyl radical is derived from a saturated hydrocarbon of the methane series are not of any special importance. When, however, we study another series of hydrocarbons known -as the unsaturated hydrocarbons we shall find important derivatives which occur in nature. We shall then refer to this study of the general relationships which we have here discussed. 

Henze, H.R. and Blair, C.M. (1931b) The number of isomeric hydrocarbons of the methane series. 

These hydrocarbons are in open chain and are often written in a condensed form as CH4, C2H6, C3H3, C4H10 or C5H12. The general formula for the hydrocarbons of the methane series is CnH2n + 2. 

Propane, CaHs, is a gas and shows the same inertness to chemical reagents as is shown by the other hydrocarbons of the methane series. It can be condensed to a liquid, which boils at —44.5°. The methods of preparation and properties of propane lead to the conclusion that it is a methyl derivative of ethane. It can be prepared by the action of sodium on a mixture of methyl iodide and ethyl iodide —... 

The oxidation state of carbon in hydrocarbons of the methane series is zero... 

THERMAL CONDUCTIVITY OF LIQUID HYDROCARBONS OF THE METHANE SERIES. 

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