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Title: Alkylation reaction: isopentane plus propylene in the presence of concentrated sulfuric acid (in German)

Technical Report ·
OSTI ID:6748598

The alkylation reaction mentioned above was originally not as well thought of as the standard alkylation reaction involving isobutane and butylene, because of the fact that (1) not so much pentane as butane was available, (2) pentane could be used as itself in gasoline, (3) the use of propylene was not very advantageous, and (4) the product had a rather low octane number (70 to 71 by motor method). The series of experiments reported here were intended to investigate a wider range of conditions for the reaction than previously investigated, in order to see if it could be made more advantageous. Topics investigated included dependence of yield, product division and properties, and usage of sulfuric acid on temperature, throughput, reaction time, proportions of reactants, and concentration of acid. The mechanism of the reaction was apparently a condensation catalyzed by sulfuric acid, with the most predominant product (45%) being 2,4-dimethylhexane, indicating that the branch carbon on the isopentane joined with the middle carbon of the propylene. An interfering side reaction was one in which the propylene formed an unreactive ester with the sulfuric acid and was lost to the reaction. The side reaction could be minimized (to about 10% loss of propylene) by using a great excess of pentane (10:1 ratio or more). The optimum temperature range for the reaction seemed to be 25/sup 0/ to 30/sup 0/; below that too much acid was lost to ester, above that, too much polymerization and oxidation took place. The smallest attained usage of sulfuric acid was 0.71 kg H/sub 2/ SO/sub 4//kg alkylate. The yield in this run was 251 g alkylate/100 g propylene and the time--space yield was 0.11 kg alkylate/liter of reaction volume/hr. However, changes in reaction conditions seemed to cause little change in product characteristics. Since the octane number was still too low, and since usage of acid and propylene was too high, the experiments produced no improvement in outlook for the reaction.

Research Organization:
I.G. Farbenindustrie, A.G., Merseburg (Germany)
OSTI ID:
6748598
Report Number(s):
TOM-301-1127-1145
Country of Publication:
United States
Language:
German