Octane number chemical

Chemical octane number the octane number added to gasoline by refinery processes or by the use of octane number (q.v.) improvers such as tetraethyl lead. 

The analyst now has available the complete details of the chemical composition of a gasoline all components are identified and quantified. From these analyses, the sample s physical properties can be calculated by using linear or non-linear models density, vapor pressure, calorific value, octane numbers, carbon and hydrogen content. 

Because of the existence of numerous isomers, hydrocarbon mixtures having a large number of carbon atoms can not be easily analyzed in detail. It is common practice either to group the constituents around key components that have large concentrations and whose properties are representative, or to use the concept of petroleum fractions. It is obvious that the grouping around a component or in a fraction can only be done if their chemical natures are similar. It should be kept in mind that the accuracy will be diminished when estimating certain properties particularly sensitive to molecular structure such as octane number or crystallization point. 

In order to characterize the behavior of motor fuels or their components with regard to knocking resistance but without involving chemical composition criteria which are complex and not easy to quantify, the traditional method that has been universally employed for more than 50 years consists of introducing the concept of octane number. 

Chemical Structures Effective in Improving the Gasoline Octane Number... 

Benzene, toluene, and xylene are made mosdy from catalytic reforming of naphthas with units similar to those already discussed. As a gross mixture, these aromatics are the backbone of gasoline blending for high octane numbers. However, there are many chemicals derived from these same aromatics thus many aromatic petrochemicals have their beginning by selective extraction from naphtha or gas—oil reformate. Benzene and cyclohexane are responsible for products such as nylon and polyester fibers, polystyrene, epoxy resins (qv), phenolic resins (qv), and polyurethanes (see Fibers Styrene plastics Urethane POLYiffiRs). 

Increasing the octane number of a low-octane naphtha fraction is achieved by changing the molecular structure of the low octane number components. Many reactions are responsible for this change, such as the dehydrogenation of naphthenes and the dehydrocyclization of paraffins to aromatics. Catalytic reforming is considered the key process for obtaining benzene, toluene, and xylenes (BTX). These aromatics are important intermediates for the production of many chemicals. 

Another important use of RMs is the maintenance of conventional scales. The octane number of gasoline is an example of such a scale. The scale is defined through chemicals. This definition can be realized through RMs. Another example is the pH scale, which is defined by buffers with pH = 4, pH = 7, and pH = 10. These buffers are defined as mixtures of salts, dissolved in water. These define the pH scale can be used by laboratories for the purpose of calibrating their pH meters. 

Fuel octane number, 72 392, 395 Fuel oil, as a petroleum product, 78 669 Fuel oil additives amine oxides, 2 473 fatty amines, 2 534 Fuel properties, of ethers, 70 574 Fuel sources, chemical industry, 70 136 Fuel spills, hydrazine, 73 588 Fuels production, hydrocracking for, 76 842-844 Fuel sulfur, 70 54... 

R. Meusinger and R. Moros, Determination of octane numbers of gasoline compounds from their chemical structure by C NMR spectroscopy and neural networks. Fuel, 80, 613-621 (2001). 

Straight-run gasoline gasoline produced from petroleum by distillation, without use of cracking or other chemical conversion processes. Its octane number is low. 

A few comments on toluene Toluene (C6H5CH3) is extensively used in gasoline to boost the octane number it is also the raw material in the production of other chemicals such as benzene, benzyl chloride, phenol, cresols, vinyl toluene, and TNT. It also finds use in the production of paints, coatings, adhesives, etc. 

A comparison has been made of Platforming and of thermal reforming from the standpoint of yield-octane number relationships, product properties, hydrocarbon types, and with respect to the nature of chemical reactions responsible for improvement of octane number. Comparison is based on studies of thermal reforming in a commercial operation at a Pennsylvania refinery and in a pilot plant on a midcontinent naphtha and in pilot plants and laboratory Platforming on the same stocks. 

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