Co-pyrolysis of an aromatic petroleum residue with triphenylsilane

Abstract The effect of silicon on the pyrolysis of a petroleum residue has been studied. In this work, controlled co-pyrolysis of an aromatic petroleum residue and triphenylsilane, TPS, as a silicon source, under 1 MPa nitrogen atmosphere and at 440°C is performed. Soaking time was varied between 1.5 and 6 h, and the silicon concentration added to the petroleum residue ranged from 0 to 2 wt%. Silicon content in the final solid product increases with soaking time. The effect of silicon upon the solid yield, insoluble content and mesophase development is appreciable only when the concentration of silicon in the residue is above 0.4 wt%. Initially TPS acts as a diluting agent and a mild proton donor, inhibiting reactivity of the radicals formed in the system and molecular growth. As reaction progresses TPS reacts, creating tetrahedral bonds within macromolecules and, as a consequence, after a period, molecular growth is enhanced. However, the planar stacking leading to mesophase formation and growth is inhibited by silicon and consequently the development of mesophase structures is limited to small spheres and fine mosaics. Optically isotropic material is obtained when silicon concentration is above 1 wt%.