Octane rating

Small amounts of tert butyl methyl ether increase the octane rating of gasoline Before environmental concerns placed limits on its use the demand for MTBE exceeded the supply... 

Octane rating (Section 2 16) The capacity of a sample of gasoline to resist knocking expressed as a number equal to the percentage of 2 2 4 trimethylpentane ( isooctane ) in an isooctane-heptane mixture that has the same knocking characteristics... 

Reforming (Section 2 16) Step in oil refining in which the pro portion of aromatic and branched chain hydrocarbons in petroleum is increased so as to improve the octane rating of gasoline... 

Uses. Diketene is described as having bactericidal activity (136,137). It also raises the octane rating of gasoline (138) but is not used for these purposes in the Western world. 

The normal paraffins produced are raw materials for the manufacture of biodegradable detergents, plasticizers, alcohols, and synthetic proteins. Removal of the / -paraffins upgrades gasoline by improving the octane rating. 

R — Research method octane rating, ASTM D2699 M = motor method octaine rating, ASTM D2700. 

The octane number of a fuel is a measure of the tendency of the fuel to knock. The octane scale has a minimum and maximum based on the performance of reference fuels. In the laboratoi"y, these are burned under specific and preset conditions. One reference fuel is normal heptane. This is a very poor fuel and is given an octane rating of zero. On the opposite end of the scale is iso-octane (2,2,4 trimethyl pentane). Iso-octanc is a superior fuel and is given a rating of 100. 

An octane rating scale was devised for fuels to quantify their knock resistance. Further research led to cataloguing the antiknock qualities of the myriad individual hydrocarbon species found in gasoline. 

By the early 1930s, thermal cracking had achieved a fairly high level of operation. Both the Dubbs (UOP) and Tube-and-Tank (Jersey Standard) Processes represented the state of the art in the field. Between the end of World War I, when the Burton Process was still revolutionary, and the early 1930s, octane ratings of gasoline increased 36 percent. This improvement resulted from the existence of more advanced thermal plants and the increasing use of additives, espe-... 

An alternative method for separating the hutenes is hy extracting isobutene (due to its higher reactivity) in cold sulfuric acid, which polymerizes it to di- and triisohutylene. The dimer and trimer of isobutene have high octane ratings and are added to the gasoline pool. 

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