Solid paraffinic carbon chains

PARAFFIN. (1) Also called alkane. A class of aliphatic hydrocarbons characterized by a straight or branched carbon chain generic formula CBH2n+2- Their physical form varies with increasing molecular weight from gases (methane) to waxy solids. They occur principally in Pennsylvania and mid-continent petroleum. (2) Paraffin Wax. 

A more detailed description of the GTL process is (1) the prodnction of synthesis gas (syngas) from carbon-based feedstocks, (2) the FT reaction for conversion of syngas to higher liqnid hydrocarbons and long-chain waxy paraffins, and (3) the conversion of the solid long-chain waxy paraffins through hydrocracking and hydroisomerization back to liquid fuels. 

Paraffin waxes are hydrocarbons with short (Cis) carbon chains. In pharmacy preparation the solid (Hard paraffin), liquid (Liquid paraffin and Light liquid paraffin) and soft type (White soft paraffin and Yellow soft paraffin) are used. They have a role in cutaneous preparations (see Sects. 12.7.9, 12.7.12, and 12.7.13) and eye ointments (see Sect. 10.7.3). 

The unsaturated open-chain hydrocarbons include the alkene or olefin series, the diene series, and the alkyne series. The alkene series is made up of chain hydrocarbons in which a double bond exists between two carbon atoms. The general formula for the series is CnH2n, where n is the number of carbon atoms. As in the paraffin series, the lower members are gases, intermediate compounds are liquids, and the higher members of the series are solids. The alkene series compounds are more active chemically than the saturated compounds. They react easily with substances such as halogens by adding atoms at the double bonds. 

In the normal paraffin chains containing four or more carbons many different conformations are conceivable. In the solid, however, the Raman spectra show that all are in the fully extended conformation, so that there is a trans arrangement at all C-C bonds (11,18). In the liquid state a number of conformations coexist, with one of them being the extended-chain one provided the number of carbons is not too large. However, in cetane, with 16 carbons, the Raman lines arising from the extended form are no longer detectable in the liquid. 

Paraffin wax is a solid crystalline mixture of straight-chain (normal) hydrocarbons ranging from 20 to 30 carbon atoms per molecule and even higher. Wax constituents are solid at ordinary temperatures [25°C (77°F)], whereas petrolatum (petroleum jelly) does contain both solid and liquid hydrocarbons. The melting point of wax is not always directly related to its boiling point, because wax contains hydrocarbons of different chemical structure. 

Paraffins are the alkane hydrocarbons (straight or branch chained, noncyclic, aliphatic hydrocarbons) the simplest of which is methane, CH4, a gas. With more carbons, paraffins become liquid and eventually waxy solids. Chlo-... 

Ceramics are usually associated with mixed bonding—a combination of covalent, ionic, and sometimes metallic. They consist of arrays of interconnected atoms there are no discrete molecules. This characteristic distinguishes ceramics from molecular solids such as iodine crystals (composed of discrete h molecules) and paraffin wax (composed of long-chain alkane molecules). It also excludes ice, which is composed of discrete H2O molecules and often behaves just like many ceramics. The majority of ceramics are compounds of metals or metalloids and nonmetals. Most frequently they are oxides, nitrides, and carbides. However, we also classify diamond and graphite as ceramics. These forms of carbon are inorganic in the most basic meaning of the term they were... 

Later work with various binary liquid mixtures and different types of solids indicated that the flow calorimeter methods of specific surface determination can also be applied to homogenous surfaces represented by graphitised carbon blacks. In this case strong preferential adsorption of long-chain paraffins from n—heptane was used to produce a monolayer and the corresponding heat of adsorption measured the total graphitic basal plane in such carbons [11]. 

The paraffin and microcrystalline waxes are mixtures of solid, saturated hydrocarbons that are produced by distillation and solvent refining from crude oil. The paraffin waxes are mostly linear alkanes with chain lengths varying from about 20 to about 50 carbons. The microcrystalline waxes contain many more branched chains and/or cyclic... 

Waxes. Waxes are a variation of oil molecules, are the solid form of hydrocarbon alkane chains more than about 20 carbons long, and are insoluble in water. These materials are usually amorphous plastic solids at room temperature, very hydrophobic, and can be found in many plants and organisms acting as a waterproof coating. Some natural waxes include beeswax, lanolin, and carnauba. Paraffin wax is typically derived from crude oil for commercial use, although many plant waxes are very similar in composition, a mixture of mostly straight-chain hydrocarbons. 

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