Motor fuels volatility

The density and the volatility, expressed by the distillation curve and the vapor pressure, constitute the most important physical characteristics of motor fuels for obtaining satisfactory operation of a vehicle in all circumstances. 

Hexane spilled onto surface soils will also volatilize to the air. Data sources were not identified allowing comprehensive quantitative estimates of the amount of -hexanc released on an annual basis to the air. In addition to releases from such commercial applications as edible oil extraction, the other major sources of atmospheric releases would be from emissions related to the -hexane contained in heating and motor fuels. 

The application of catalysis to the production of motor fuel by cracking of less volatile petroleum oils was first investigated in France by Eugene J. Houdry in the period 1927 to 1930. The results from these investigations clearly established the superiority of catalytically cracked gasoline over that made by the thermal processes the economic possibilities were also indicated. 

The present status of jet fuel technology can be aptly described as being at the same point as motor fuel technology 25 years ago. Volatility and stability requirements have been recognized and current research activities are directed toward the solution of these problems. 

In comparing propane and butane as direct motor fuels we may also remember that no penalty has been paid in the way of refining losses (19) to realize the high octane numbers which these fuels have. Neither has the cost of expensive catalytic processes for upgrading been incurred. From an over-all economic standpoint it is felt that these considerations can well offset the small extra cost of handling these volatile liquids under pressure. 

Upgrading of natural-gas liquids to motor fuels with customary technology used in the petroleum industry (isomerization, hydroisomerization, etc.) represents difficulties. One reason is that the volatility of motor fuels cannot be increased, thus limiting treatments such as hydrocracking. 

A few other comments Ethanol is listed by OSHA as a suspect but unproved carcinogen, but OSHA does not have jurisdiction over beverage alcohol, nor, since it is a natural product, does the Delaney Amendment apply. This could lead to paradoxical situations. Ethanol will continue to grow explosively in volume in the next few years as a motor fuel indeed, this has happened in Brazil. The field is extremely volatile, and new developments occur every week, particularly with respect to fermentation and gasohol. Things should be clearer in about five years, and we should remind ourselves to take a similar look at ethanol then. 

The mixed methyl-ethyl tetraalkyllead compounds have become quite important commercially in the past several years because of their excellent antiknock effects and volatilities (see Extent of Antiknock Effect). Sometimes tetramethyllead and tetraethyllead are simply mixed together in motor fuel, but usually the compounds are subjected to "redistribution of the methyl and ethyl groups. The redistribution reaction involves the exchange of the organic groups between the compounds, yielding practically a random equilibrium production of all the possible products in a statistical distribution, as shown in the equation ... 

Synonyms/Trade Names Motor fuel, Motor spirits, Natural gasoline. Petrol [Note A complex mixture of volatile hydrocarbons (paraffins, cycloparaffins aromatics).] ... 

Because n-heptane must be extremely pure for use as the standard zero in the testing of motor fuels for motor octane number, it is available for use as a pure solvent. In practice, such a grade is seldom used except as a laboratory reagent. Narrow boiling range petroleum cuts primarily consisting of n- and isoalkanes have solvent properties similar to n-heptane and are very much less expensive. Repeated recovery may result in the more volatile compounds not being stripped completely from solutions but the overall solvent and volatility properties of recovered solvent... 

Incomplete combustion of gasoline and other motor fuels releases significant quantities of volatile organic compounds (VOCs) into the atmosphere. VOCs are composed of short-chained alkanes, alkenes, aromatic compounds, and a variety of other hydrocarbons. VOCs are components of air pollution and contribute to cardiac and respiratory diseases. 

The dry vapor pressure equivalent (DVPE) of volatile motor fuels is regulated by federal and state air pollution control agencies. In order to meet the letter of these regulations, it is necessary to sample, handle, and test these products in a very precise manner. 

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