The role of limonene in the branching of straight chains in low-octane hydrocarbons

Limonene has great potential as a bio-additive. It has physical characteristics resembling those of fuel oil and has a molecular structure that could potentially allow limonene to be used as an octane booster. With an octane number of only 88, limonene is able to increase RON. The increase was caused by limonene stimulation, which improved the molecular structure, resulting in straight-chain branching. To investigate the molecular interactions between limonene and blended fuel, n-heptane was chosen as a fuel to represent low-RON fuel. Limonene and n-heptane were blended, so the effect of limonene on n-heptane could be observed. Analysis was conducted by using HyperChem, which was validated by the experiment to calculate the important molecular properties of each fuel blend. Spaya.ai artificial software was used to track the straight-chain branching schematic routes and then the mechanisms were detected. The results showed that there was a significant increase in RON in the blending of n-heptane and limonene. Limonene at a concentration of only 1% was able to increase the RON of n-heptane from 0 to 91.15, which exceeds RON of limonene. This increase was due to the change in molecular interaction energy causing a change in the shape of the molecular structures.