Characteristics of Isohexene as a Novel Promising High-Octane Gasoline Booster

Oil refineries strive to maximize the production of high-octane components using selective dimerization of olefin-containing gases. A known process is the technology for the production of diisobutylene (isooctene); the properties of this product are well-known. Another, less well-known process is the process of producing isohexene as the product from the dimerization of propylene, and its properties are poorly described in the literature. This research introduces a novel simple strategy to employ isohexene as a promising high-octane gasoline booster intended for internal combustion engines. Physicochemical characteristics of the isohexene sample were examined in agreement with all specifications of Russian and European standards (GOST 32513-2013 and EN 228:2012). The comparison between isohexene and others gasoline components, such as base automotive gasolines, MTBE, as well as TAME, has been done in order to assess the detonation resistance performance of isohexene at a concentration of 15 wt % from each gasoline component. The results demonstrated that the use of isohexene as an automotive gasoline booster has great prospects due to its high-octane rating at the degree of MTBE, in addition to isohexene owning low volatility which causes a reduction in RVP of base gasoline, but to a lesser extent than TAME. Likewise, the oxidation stability of isohexene is not high, and to overcome this problem, an antioxidant, such as agidol-1, was added. Furthermore, when the concentrations of isooctene (diisobutylene) and isohexene with isooctane were up to 60 and 10 wt %, respectively, the oxidation stability value was above the Russian and European standard regulations of 360 min intended for an automotive gasoline. Finally, the detonation resistance performance of isohexene was also estimated with various refinery gasoline products, involving blend “70”, reformate, isomerate, and fluidized catalytic cracking (FCC) naphtha, and the results illustrated that calculated isohexene blend octane numbers ranged from 104.3 to 144.5 by the research techniques and from 83 to 121.5 by the motor techniques.