Boiling range

The above-mentioned criteria only refer to watery solutions, but those with a high boiling point also have to be mentioned. These are, for example, saturated hydrocarbons with more than six C-atoms. For an atmospheric evaporation heating temperatures of up to 300 °C are required. 

Low boiling temperature and thus, low heating temperatures can be also achieved with vacuum. 

For diphenyl (Cj 2Hio)) for example, the boiling temperature can be reduced from 255.9 to 150.7 °C by reducing the pressure from 1000 to 100 mbar. 

A vacuum operation is absolutely required for substances with a high boiling point. 

There are several ways to classify or group various petroleum products. Refined oils are sometimes characterized by the approximate boiling-point range, which corresponds with the size (such as the number of carbon atoms) of the petroleum hydrocarbons in the refined oil  

1 to 205°C (32 to 400°F) naphtha or straight-run gasoline (meaning, not produced through catalytic decomposition). 

205-345°C (400 to 655°F) middle distillates, including kerosene, jet fuel, heating oil, and diesel fuel. 

565°C- - (1050°F- -) residuum, which may be cut with lighter oil to produce bunker oil and other fuel oil. 

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Crude tar is normally distilled in continuous plant into distillate fractions which can vary in boiling range and in name, leaving pitch as a residue. 

Distillation simulated by gas chromatography is a reproducible method for analyzing a petroleum cut it is appiicabie for mixtures whose end point is less than 500°C and the boiling range is greater than 50°C. The results of this test are presented in the form of a curve showing temperature as a function of the weight per cent distilled equivalent to an atmospheric TBP. 

Their production in a refinery begins with base stocks having narrow boiling ranges and high octane numbers iso C5 cuts (used in small concentrations because of their high volatility) or alkylates are sought for such formulations. 

The special boiling point spirits (SBP s) have boiling ranges from 30 to 205°C and are grouped in subdivisions according to Table 6.1. 

White-spirits are solvents that are slightly heavier than SBP s and have boiling ranges between 135 and 205°C. A dearomatized grade exists. These solvents are used essentially as paint thinners although their low aromatic content makes them unsuitable for lacquers, cellulosic paints and resins. 

Two derivatives are used to ensure constant lead content throughout the gasoline boiling range tetraethyl- and tetramethyl lead and their mixtures in variabie proportions. 

In most cases boiling points of small, intermediate fractions are given, instead of the more usual boiling ranges. 

Temperature and pressure are not considered as primary operating variables temperature is set sufficiendy high to achieve rapid mass-transfer rates, and pressure is sufficiendy high to avoid vaporization. In Hquid-phase operation, as contrasted to vapor-phase operation, the required bed temperature bears no relation to the boiling range of the feed, an advantage when heat-sensitive stocks are being treated. 

The olefin product contains 1.1% of residual / -paraffins. Essentially similar results have been obtained in commercial operations on Cg—C q and C g feedstocks. The desorbents used are generally hydrocarbon mixtures of lower boiling range than the feed components. The concentrated olefin stream may then be used for production of detergent alcohols. 

Name Molecular formula Hydroxyl Value Acidity, % as acetic Carbonyl, wt % 0 Boiling range, °C Color, APHA Moisture, % Plash point, °C ... 

Other than fuel, the largest volume appHcation for hexane is in extraction of oil from seeds, eg, soybeans, cottonseed, safflower seed, peanuts, rapeseed, etc. Hexane has been found ideal for these appHcations because of its high solvency for oil, low boiling point, and low cost. Its narrow boiling range minimises losses, and its low benzene content minimises toxicity. These same properties also make hexane a desirable solvent and reaction medium in the manufacture of polyolefins, synthetic mbbers, and some pharmaceuticals. The solvent serves as catalyst carrier and, in some systems, assists in molecular weight regulation by precipitation of the polymer as it reaches a certain molecular size. However, most solution polymerization processes are fairly old it is likely that those processes will be replaced by more efficient nonsolvent processes in time. 

Web Heat-Set Publication and Commercial Inks. Almost all heat-set inks are now printed on web offset presses, and are based on vehicles containing synthetic resins and/or some natural resins. These are dissolved in hydrocarbon solvent fractions which are specially fractionated for use in the ink industry. They vary in boiling range between 180 and 300 °C. Small percentages of alkyd resins (qv) may be contained in these inks. They dry in less than one second by means of solvent evaporation in a heatset oven. These ovens utilize high velocity hot air to raise the web temperature to 120-150 °C. 

Solvent Comparative drying Boiling range. Flash point. Density at 20°C,... 

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. 

The Ni and V concentrated into the vacuum resid appear to occur in two forms. Erom 10 to 14% of each of these two metals can be distilled in the 565—705°C boiling range, where they exhibit the strong visible Soret bands associated with the porphyrin stmcture. This tetrapyrrole stmcture (48,49), possibly derived from ancient chlorophyll, has been confirmed by a variety of analytical techniques. 

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