Boiling ranges of fractions

Boiling Range of Fraction (°C) Number of Carbon Atoms per Molecules Use... 

Small differences in the boiling points of the xylene isomers make the preparation of pure m- xylene by distillation impossible, Nevertheless, boiling ranges of fractions suitable for nitration can be established. 

Coal liquids need to be refined to finished products such as jet fuels and diesel by hydrotreating and hydrocracking. Before GC-MS analysis of coal-derived JP-8 fuels, these fuels were first tested by separation into five distillate fractions using a fractional distillation apparatus. Table 32.9 lists the yields and boiling range of fractional distillation [33]. 

S-compounds, N-compounds and M (Metal) compounds have different reactivities and chemistry depending on the boiling ranges of fractions in which they are found. Thus, specific processes have been developed for the removal of each of these impurities. These are classified as hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and hydrodemetallation (HDM) processes, respectively. These are in turn subdivided into processes, which are optimized for the boiling range of the particular feedstock being treated. 

Naphthenic acids occur ia a wide boiling range of cmde oil fractions, with acid content increa sing with boiling point to a maximum ia the gas oil fraction (ca 325°C). Jet fuel, kerosene, and diesel fractions are the source of most commercial naphthenic acid. The acid number of the naphthenic acids decreases as heavier petroleum fractions are isolated, ranging from 255 mg KOH/g for acids recovered from kerosene and 170 from diesel, to 108 from heavy fuel oil (19). The amount of unsaturation as indicated by iodine number also increases in the high molecular weight acids recovered from heavier distillation cuts. 

The naphtha fraction is dorninated by saturates having lesser amounts of mono- and diaromatics (Table 2, Eig. 4). Whereas naphtha (ibp to 210°C) covers the boiling range of gasoline, most raw petroleum naphtha molecules have a low octane number and most raw naphtha is processed further, to be combined with other process naphthas and additives to formulate commercial gasoline. 

Naphtha is a generic term normally used in the petroleum refining industry for the overhead liquid fraction obtained from atmospheric distillation units. The approximate boiling range of light straight-run naphtha (LSR) is 35-90°C, while it is about 80-200°C for heavy straight-run naphtha (HSR). ... 

TABLE 18.2 Hydrocarbons Hydrocarbon Constituents of Petroleum Boiling range (°C) Fraction... 

The ethereal product solution is dried with anhydrous sodium sulfate and filtered. Then the ether is evaporated from the filtrate. The residue is purified by fractional distillation under reduced pressure. The main fraction has a boiling range of 56°-58°C (15 mm Hg). The product is a blue liquid of unpleasant odor which is also lachrymatory yield 12.6 gm (82%), d° 1.4321. 

After sufficient information has been obtained as to the types of components which constitute a given fraction or boiling range of petroleum, subsequent examination of such material can be greatly simplified by the elimination of certain steps. In most cases, for example, it becomes unnecessary to make an elemental analysis or determine the molecular weight. 

Materials. Ethanethiol, obtained from the Eastman Kodak Co., was distilled under nitrogen at atmospheric pressure. The middle fraction collected had a boiling range of less than 0.1°C. and was stored under nitrogen at 0°C. in a vessel fitted with a rubber serum cap. Alkaline solutions were prepared from AnalaR sodium hydroxide (Hopkin and Williams) and deionized distilled water and were stored in steam-cleaned screw-capped polyethylene bottles. 

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