Paraffinic compounds

Toxicological Information. The toxicity of the higher olefins is considered to be virtually the same as that of the homologous paraffin compounds. Based on this analogy, the suggested maximum allowable concentration in air is 500 ppm. Animal toxicity studies for hexene, octene, decene, and dodecene have shown Httle or no toxic effect except under severe inhalation conditions. The inhalation LD q for 1-hexene is 33,400 ppm for these olefins both LD q (oral) and LD q (dermal) are >10 g/kg. 

The carbocation may rearrange, eliminate a proton to produce an olefin, or crack at a beta position to yield an olefin and a new carbocation. Under an atmosphere of hydrogen and in the presence of a catalyst with hydrogenation-dehydrogenation activity, the olefins are hydrogenated to paraffinic compounds. This reaction sequence could be represented as follows ... 

Uses of Nitric Acid. The primary use of nitric acid is for the production of ammonium nitrate for fertilizers. A second major use of nitric acid is in the field of explosives. It is also a nitrating agent for aromatic and paraffinic compounds, which are useful intermediates in the dye and explosive industries. It is also used in steel refining and in uranium extraction. 

Some paraffin compounds containing both I and NOj groups are explosive, for example ... 

Table 4.35. H Chemical Shifts of Paraffinic Compounds with T yo Functional Groups...

Separation of paraffinic and aromatic hydrocarbons. Liquid paraffinic hydrocarbons (such as pentane, hexane, and heptane) and liquid aromatic hydrocarbons (such as benzene, toluene, and xylene) have different chemical characteristics for example, the paraffinic compounds are almost completely immiscible with liquid ethylene glycol, while aromatic compounds and ethylene glycol readily form homogeneous liquid mixtures. Parafflnics and aromatics may therefore be separated from each other by blending a mixture of the two... 

Aromatic Compounds—The carbo-cyclic compounds which in number far exceed those of the aliphatic series were originally called aromatic compounds because many of them possess aromatic properties, e.g.j oil of wintergreen, oil of bitter almonds, etc. They were included with the paraffin compounds in the various groups of alcohols, aldehydes, acids, etc. Later it was found that they differed from the aliphatic compounds and finally it was shown that the hydrocarbon benzene is related to the aromatic compounds just as methane is to the aliphatic compounds, i.e,j as the mother substance. 

Theories of Formation of Benzene, etc.—Theories of the formation of these benzene products in the distillation of coal have been investigated principally by Berthelot, and his conclusions are, in general In the first place, coal decomposes by heat yielding simple paraffin compounds such as methane, ethylene, acetylene, alcohol, acetic acid, etc. These compounds when subjected to higher temperatures polymerize into benzene, and the higher hydrocarbons naphthalene, anthracene, phenanthrene, etc., and into derivatives of these such as phenol, aniline, pyridine, etc. 

To get an initial estimate of the distillation column conditions, the process was first simulated using a shortcut column model, as shown in Figure 4.43. If we assume that no cyclic compounds are formed in the process, then the component list includes all of the available Cg paraffin compounds, i.e., n-hexane, 2-methyl pentane, 3-methyl pentane, 2,3-methyl butane, and 2,2-methyl butane. The reactor achieves complete equilibrium between these species and so can be modeled using a Gibbs reactor. 

The for crude oil and its fractions generally range between 10 (highly naphthenic crude) and 13 (highly paraffinic crude). For highly aromatic compounds to highly paraffinic compounds, the value of usually ranges between 10 and 15, respectively, and therefore, can be said to be a qualitative measure of either the aromaticity or the paraffinicity of a crude oil. 

It was determined that approximately four times more bitumen-free organic matter is associated with silicate minerals than with carbonate minerals. The major structural constituent of the various filtrate fractions was paraffinic compounds. However, spectroscopic analysis indicated relatively larger concentrations of olefins and branched paraffins with the acid/ether extracted... 

Until fairly recently, chlorinated hydrocarbons dominated the halogenated hydrocarbon field. This was undoubtedly due to the cheapness and availability of chlorine and the ease with which it reacted with paraffinic compounds. Recently fluorine compounds have received a great deal of attention. In reviews of the general field up to about 1947 or 1948, the attention is largely on chlorine since then, it has been about equally distributed between chlorine and fluorine. 

The aniline (or mixed aniline) (ASTM D-611, IP 2) point helps in characterization of pure hydrocarbons and in their mixtures and is most often used to estimate the aromatic content of naphtha. Aromatic compounds exhibit the lowest aniline points and paraffin compounds have the highest aniline points, with cycloparaffins (naphthenes) and olefins having aniline points between the two extremes. In any homologous series the aniline point increases with increasing molecular weight. 

Figure 1 shows the DTA curve obtained when a sample of diesel soot is burned in the absence of a catalyst. With increasing the temperature, four exothermic peaks appear. These peaks can be attributed to the combustion of different types of hydrocarbons constituting the soot (11). Indeed, it is known that a real soot consists of a volatile fraction, which is more active than a carbonaceous solid fraction. The composition of the volatile fraction can also vary depending on the quality of fuel and the engine s mode of operation. In some cases, aromatic, oxygenated and paraffinic compounds can be present, as well as residual coke of the lubricant (12). 

The presence and the number of double bonds. Crystallization of paraffinic compounds is difficult but occurs easiest if the chains can assume a linear zigzag conformation. A chain with a cis double bond cannot do this it tends to form a bend (see Figure 15.19b, SOS). This makes crystallization more difficult. The effect will be greater for more double bonds. Cf. the series SSS-OOO-LiLiLi-LnLnLn. 

It is known that paraffins from methane to butane are gases, from C5 till Cl7 are liquids, and from Ci8 onwards are solid substances. The solid paraffins are present in all cmde oils in different amounts, often up to 5%, but in some cmde oils up to 7% or even 12% have been found. Solid fractions of cmde oils do not only contain paraffins, but indeed these solids are complicated mixtures of paraffins, naphthenes, aromatics and other compounds. It has been shown that some heavy fractions from paraffinic oils can contain up to 50% paraffins, 47% naphthenes and up to 3% aromatic compounds. It is known that the higher the boiling temperatures of the erode oil fraction, the less the amount of paraffinic compounds present in the fraction. However, paraffins are present in smaller or higher amounts in all cmde oils, cmde oil fractions and products. The kind and how the paraffins are present in oil (i.e. gas, solved or dispersed) depend on the properties of the erode oil and the chemical conditions of paraffins. 

In the mechanism involving catalysis on metals during catalytic cracking, the catalyst promotes the removal of a negatively charged hydride ion from a paraffin compound. The mechanism in this type of catalysis is illustrated in Figure 6.8. 

The reactivity of 2- C-isopropanol adsorbed on K- and Cs-ZSM-5 zeolites is examined in a batch-reactor (681. Propylene is formed by dehydration at 200°C (Figure 18). The subsequent polymerization of propene to form paraffinic compounds is quite significant on K-ZSM-5, while Cs-ZSM-5 yields only ca 10 %... 

During the extraction of otganic species, it may be desirable to modify the solvent. An inert paraffinic compound or mixture may be blended with a suitable modifier (e.g., a species that hydrogen bonds) to enhance the solvent properties. Such properties might include viscosity, density, surface tension, or attraction for the solute. In these cases, the mutual solubility curve may appear as in Fig. 7.2-4 when the solvent mixture is plotted at one vertex. Reasons for solvent blending may include improved solvent selectivity, interiacial tension, reduced solvent phase viscosity, and increased density differences between the two phases. A solvent that forms stable etnulstotte when mixed with the diluent phase, for example, may be suitable for use when it is modified with a suitable inert paraffinic material. 

Xing, J. Li, Y. Newton, E. Yeung, K.-W. Method for encapsulating phase-transitional paraffin compound and their microcapsules. US 20030222378, 2003. 

This type of PCM is divided in paraffin compounds and nonparaffin compounds (fatty acids mostly). Principal advantages of organic PCM are the chemical and thermal stability, they are noncorrosive, they are recyclable, and they have no subcooling. On the other hand, the disadvantages are their flammability, low thermal conductivity (k), and low phase change enthalpy. 

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