Octane rating system

The branched alkane 2,2,4-trimethylpentane is an important component of gasoline and the standard on which the octane rating system for liiei efficiency is based. The car engine shown above requires high-octane fuei to achieve the performance for which it is famous. 

The desire to improve the octane rating of fuels after the refining process without the use of lead has intensified a search for other "antiknock compounds. For example, compounds of Mn (5) and Ce (9) have been explored for this purpose. Methylcyclopentadienyl manganese tricarbonyl, in particular, is already being marketed for octane improvement. At a recommended level of 0.125 g Mn/gal, 200-500 g of Mn can be expected to pass the exhaust system within 50,000 miles. The main criteria in accepting such fuel additives are their compatibility with catalytic systems, and, of course, health-safety considerations. 

Fig. 16.3 Reformer unit control based on reformate product octane rating setting the temperature of the reactor feed, and catalyst regeneration system. (O2, An), (H, An) and (O.N., An) are the oxygen, hydrogen and octane number analysers, respectively.

The most predominant application of the process gas chromatograph is to provide feedback for process control, in either open- or closed-loop control. In the case of a fractionation tower, one or more components are monitored, and the result then directly controls the operation of the tower. Griffen et al. (135) snmmarized the considerations involved in analyzer control of fractionators. More complex analyses are required for applications such as cracking products, polymerization reactor feed impurities, and high-purity product quality control. Systems for determination of boiling point distributions and octane ratings of refinery streams have also been developed. 

The exit rate constants for cyclohexane and p-xylene from the micelles present in the cubic phase of the sodium octanoate/octane/water system have been measured by combining TRLQ and NMR self-diffusion data on the system. The value found for p-xylene compares well with that determined on the basis of solubility measurements. ... 

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