Low molecular weight paraffins

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). 

Schultz and Linden Ind. Eng. Chem. Process Design and Development, 1 (111), 1962] have studied the hydrogenolysis of low molecular weight paraffins in a tubular flow reactor. The kinetics of the propane reaction may be assumed to be first-order in propane in the regime of interest. From the data below determine the reaction rate constants at the indicated temperatures and the activation energy of the reaction. 

The optical rotatory dispersion of poly-a-olefins (43,96,105) between 300 and 600 rn.fi is normal, the Aq of the Drude one term equation being independent of temperature and having values very near the A0 of low-molecular-weight paraffins (Table 10). 

Table 9. Molar rotatory power of the most stereoregular fractions of some poly-tx-olefins (105) and of some low molecular weight paraffins... 

The viscosities of many binary liquid systems display minima as functions of composition at constant temperature, so that negative values of D are also possible. Yajnik and his coworkers (265 ) long ago observed that very frequently an extremum in the isothermal vapor pressure-composition curve is accompanied by an extremum of the opposite sense in the viscosity-concentration curve. Data are apparently not available for solutions of very low-molecular-weight paraffins in carbon tetrachloride, but minima are found for the viscosities of solutions of CC14 with ethyl iodide, ethyl acetate and acetone, so that a minimum appears quite probable for mixtures of small aliphatic hydrocarbons with carbon tetrachloride. If this were true, the downward trend of the Meyer-Van der Wyk data on C17—C31 paraffins, earlier discussed in connection with the polyethylene plots of Fig. 14, would be understood. It will be recognized that such a trend is also precisely what is to be expected from the draining effect of the hydrodynamic theories of Debye and Bueche (79), Brinkman (45 ) and Kirkwood and Riseman (139). However, the absence of such a trend in the case of polyethylene... 

In our laboratories, we were concerned with yield of black production however, we were more concerned with the influence of feedstock structure on the quality of product produced. Molecular structures of feedstocks investigated were pure compounds and mixtures of pure and similar compounds including monocyclic aromatics with and without side chains, dicyclic aromatics, tricyclic aromatics, mixtures of higher molecular weight aromatics and high and low molecular weight paraffins. Some examples of the types of compounds studied are ... 

The activation of low molecular weight paraffins is an important process from both industrial and fundamental point of view. In this way, the oxidative dehydrogenation (ODH) would be an attractive alternative to the classical dehydrogenation. 

Oxidations of low-molecular-weight paraffin hydrocarbons to produce acetic acid remain important in today s industrial economy (eq. (1)). Such processes accounted for about 15% of the installed acetic acid capacity in both the USA and the UK in 1992. Both n-butane and light naphthas (which contain low-boiling hydrocarbons, especially pentanes and hexanes) are heavily utilized for raw materials. Butane is the raw material of choice in the USA, where it is readily available. In other areas of the world, light naphtha is often preferred [1, 2]. 

Liquid and solid samples are placed in an opened cup while volatile samples are placed in a gelatine capsule and placed in the cup as for a normal sample. A suitable absorption solution is placed at the bottom of the bomb along with the prepared sample. It may be necessary to include an aid with combustion resistant samples as a support to combustion and such additives are low molecular weight paraffin oils, ammonium nitrates, benzoic acid, decalin, etc. 

The resulting equation was found empirically by E. B. Burk (3) and M. D. Tilicheev (22). The above-studied mechanism of the cracking of n-paraffins explains the absence of dependence of the cracking rate on reaction extent. This differs from the case of the low molecular weight paraffins experimentally determined by Kasanskaya (6) and Panchenkov and Baranov (19) for n-octane and n-hexadecane. 

The effect of paraffin carbon number on the equilibrium methane concentration is shown for three feed steam-carbon ratios in Figure 6. These results indicate that a higher methane-content gas can be produced from low molecular weight paraffins than from high molecular weight paraffins. 

An example of the controlled noncatalytic oxidation of low-molecular-weight paraffin hydrocarbons to form commercially practicable yields of oxidation products is given by a process devised by Bludworth In the oxidation of butane or other low-molecular-weight paraffin hydrocarbon, he... 

Off gases are generated from both the Fischer Tropsch and reforming steps. Quality is very high (600-2500 Btu/SCF) with a heavy concentration of low molecular weight paraffins. On a commercial scale, these gases would be recycled back to the gasification system. 

Examples of lubricants for chlorinated PVC are metal stearates, montan waxes, high and low molecular weight paraffinic waxes, as well as oxidized waxes. Specific examples of external lubricants are Advalube E-2100 available from Rohm and Haas, Licolub XL 445 available from Clariant. These lubricants are used at levels ranging from 4-5.5 phr (8). 

Mixtures of butadiene-styrene copolymer (or polybutadiene) with natural rubber are often mixed with low molecular weight paraffin wax (C H2 + 2) in fire applications. The rubber components maintain their near miscibility. The paraffin wax however precipitates out and migrates to the air interface and acts as an antidegradent layer [21]. 

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