Paraffins Alkanes

Figure 5.13 Examples from the alkane (paraffin) series...

Hydrocarbons, compounds of carbon and hydrogen, are stmcturally classified as aromatic and aliphatic the latter includes alkanes (paraffins), alkenes (olefins), alkynes (acetylenes), and cycloparaffins. An example of a low molecular weight paraffin is methane [74-82-8], of an olefin, ethylene [74-85-1], of a cycloparaffin, cyclopentane [287-92-3], and of an aromatic, benzene [71-43-2]. Cmde petroleum oils [8002-05-9], which span a range of molecular weights of these compounds, excluding the very reactive olefins, have been classified according to their content as paraffinic, cycloparaffinic (naphthenic), or aromatic. The hydrocarbon class of terpenes is not discussed here. Terpenes, such as turpentine [8006-64-2] are found widely distributed in plants, and consist of repeating isoprene [78-79-5] units (see Isoprene Terpenoids). 

Polyethylene, in essence a high molecular weight alkane (paraffin), would be expected to have a good resistance to chemical attack and this is found to be the case. 

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-... 

A question which chemical enumerators should not ignore is that of the extent to which their results are realistic in the physical world. Thus in [BlaCSla] it is stated that the number of alkanes (paraffins) with 40 carbon atoms is 62,491,178,805,831. Can we really be sure that all these compounds can exist or could it be that factors not catered for in the enumeration render some of them chemically infeasible In this connection we should note the paper [KleD81], in which it is shown jthat because of such factors the chemical tree enumerations by Polya and others give numbers that are consistently higher than the number of compounds that are in fact chemically possible. This does not detract from the mathematical value of these results it merely shows that care is needed in relating them to problems of real life. 

Alkanes keep going up in size. When they get up to C18H 8 they become solids. The familiar white solid paraffin, which is commonly used for making candles, is made up of solid alkanes. Paraffin is not really a wax, as waxes are made up of more complicated molecules. 

FIG. 36 Synergistic mixture of alkane- (paraffin) sulfonates (PS) and fatty alcohol ether sulfates (FAES). Cleaning effect in miniplate test at 50°C, tap water (12° German hardness), 0.075 g of active surfactant mixture per liter. 

The first LCA study of detergent surfactants was sponsored by Procter and Gamble at Franklin Associates Ltd. (FAL) [118]. However, this study does not include alkane- (paraffin) sulfonates since they are absent from the American market. 

The spectra of normal alkanes (paraffins) can be interpreted in terms of four vibrations, namely, the stretching and bending of C—H and C—C bonds. Detailed analysis of the spectra of the lower members of the alkane series has made detailed assignments of the spectral positions of specific vibrational modes possible. 

Most artificial gases, such as producer gas. coal gas. water gas. manufactured gas. and town gas contain a high content of methane. In addition to its use as a basic chemical and fuel, methane is of notable interest because of its role as the anchor compound of the alkanes (paraffin or aliphatic hydrocarbons). All of these compounds may be considered derivatives of methane. 

The exact temperature at which the cloud point is reached depends on the total n-alkane content of the fuel, the average size of the n-alkane molecules, their size distribution and chain structure (e.g. degree of branching). Conventional diesels contain as much as 20% of long-chain n-alkanes of limited solubility in the fuel. Pyrolysis-diesels from PE feedstocks can contain more than 40% long-chain n-alkanes. Paraffins crystallize at low temperature into very thin rhombic plates which can clog filters, transfer lines, and pumps, and can lead to engine failure at low temperatures. 

That the surface tensions of solutions of d- and /-optical isomers aredififerent seems doubtful. Surface tensions of normal alkanes (paraffin hydrocarbons) containing n atoms of carbon are given by a —l4-6 log ( —3)+ll 52 within experimental error. 

A brief consideration of bacteriology introduces a simple calculation of the RQ-A variety of naicroorganisms can use long-chain alkanes (paraffin wax) or short-chain alkanes as an energy source (Van Eyk and Bartels, 1%8) The complete oxidation of alkanes has the. same outcome, whether catalyzed by a flame at a candlewick, a spark inside a furnace, or enzymes within a Jiving cell. Complete oxidation of hexane means that all of the carbon atoms arc oxidized to carbon dioxide ... 

Diesel fuel no. 1 is a straight-run middle distillate with a boiling range consistent with that of kerosene. It contains branched-chain alkanes (paraffins), cycloalkanes (naphthenes), aromatics, and mixed aromatic... 

The dehydrogenation of alkanes (paraffins) to alkenes (olefins) does not occur to a large extent at typical reforming conditions. For example, equilibrium conversion of n-hexane to 1-hexene is about 0.3% at 510°C and 17 atm hydrogen partial pressure. Nevertheless, alkane dehydrogenation is of considerable importance, since olefins appear to be intermediates in some of the reactions. This matter is discussed in more detail in a later section. 

Fig. 4.23 Major hydrocarbons and simple heteroatomic compounds in crude oils (a) acyclic alkanes (paraffins) (b) cycloalkanes (naphthenes) (c) aromatic hydrocarbons (d) sulphur-containing aromatics. (R. = alkyl group.)...

Alkanes, C10-C13, chloro CJi(2x-y+2)Cly, whereX = 10-13 andy = 1-13 CAS No. 85535-84-8, EINECS No. 287 76-5 Synonyms alkanes, chlorinated alkanes (C10-C13), chloro-(50-70%) alkanes (C10-C12), chloro-(60%) chlorinated alkanes, CPs chloroalkanes chlorocarbons polychlorinated alkanes paraffins-chlorinated Notes that there is a range of commercially available C10-C13 CPs... 

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