Straight-chain paraffin

Catalytic Oxidation for Straight-Chain Paraffinic Hydrocarbons. Synthetic fatty acids (SFA) are produced by Eastern European countries, Russia, and China using a manganese-catalyzed oxidation of selected paraffinic streams. The technology is based on German developments that were in use during World War II. The production volume in 1984 was estimated to be about 5.5 x ICf t/yr. The oxidation is highly exothermic and is carried out at about 105—125°C, mostly in continuous equipment. 

Impurities can sometimes be removed by conversion to derivatives under conditions where the major component does not react or reacts much more slowly. For example, normal (straight-chain) paraffins can be freed from unsaturated and branched-chain components by taking advantage of the greater reactivity of the latter with chlorosulfonic acid or bromine. Similarly, the preferential nitration of aromatic hydrocarbons can be used to remove e.g. benzene or toluene from cyclohexane by shaking for several hours with a mixture of concentrated nitric acid (25%), sulfuric acid (58%), and water (17%). 

Straight-Chain Paraffins 1.2 Single-Branched Paraffins ... 

Long straight-chain paraffins are important to the economics of an FCC unit. They crack easily to gasoline and LPG, with minima] production of slurry and fuel gas. 

The necessary C10/13 cut for the hydrophobic part of the molecule can be obtained by various methods. Suitable paraffins were obtained in the USA from kerosene (distillation range 200-250°C). The kerosene was extracted above all from Pennsylvania oil. These mainly straight chain paraffins with 12-14 C atoms were chlorinated and their reaction products alkylated with benzene in the presence of a Lewis acid and sulfonated with oleum. The first products in the USA were called Nacconol NR and NRSF (National Aniline and Chemical Co., NACCO ), as well as Santomerse 1 (Monsanto) [4]. 

The paraffin hydrocarbon containing four carbon atoms is called butane, but two 4-carbon (C4) paraffins are possible. The butane with its carbons in a line is known as normal butane or n-butane. The branched chain butane is isobutane or i-butane. Although each compound has the formula C4H10, they have different properties for example, n-butane boils at -0.5°C while isobutane boils at -11.7°C. n-Butane and i-butane are isomers of each other. The straight-chain paraffin is always called the normal form. 

An important reaction in the manufacture of gasoline is isomerization of straight-chain paraffins to more highly branched compounds, which have better fuel properties (higher octane rating). 

Traditionally, iron-based catalysts have been used for FT synthesis when the syngas is coal derived, because of their activity in both FTS and WGS reactions. Complex mixtures of straight-chain paraffins, olefins, and oxygenate (in substantial proportions) compounds are known to be formed during iron-based FTS. Olefin selectivity of iron catalysts is typically greater than 50% of the hydrocarbon products at low carbon numbers, and more than 60% of the produced olefins are a-olefins.13 For iron-based catalysts, the olefin selectivity decreases asymptotically with increasing carbon number. 

Urea dewaxing, in which urea forms adducts with straight-chain paraffins that separated by filtration from the dewaxed oil. 

Catalytic dewaxing, in which straight-chain paraffin hydrocarbons are selectively cracked on zeolite-type catalysts, and the lower-boiling reaction products are separated from the dewaxed lubricating oil by fractionation. 

Isomerization the conversion of a normal (straight-chain) paraffin hydrocarbon into an iso (branched-chain) paraffin hydrocarbon having the same atomic composition. 

Straight chain paraffins autoignite more readily than branched chain paraffins and aromatics of the same carbon number. 

Although not strictly relevant to this review, Schaufele and Shimanouchi (19) published a fascinating paper in November 1967 on some work they had completed upon long but finite-length, straight chain paraffins. They observed the Kaman spectrum of a series of paraffins containing 18 to 94 carbon atoms very close to the exciting line. 

CST differences between branched-chain and straight-chain paraffins are usually small. Stannic iodide is the most selective solvent found (95) but because... 

The decomposition of the alkoxy radical by Reaction 8 occurs by a-scission at the C—C bond attached to the largest hydrocarbon group (185, 229). Straight-chain paraffins produce aldehydes, while highly branched paraffins yield ketones (Reaction 11). The knock resistance of naphthenes may be caused by the stability of the naphthene ring to C—C scission (25). 

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