Oligomerization and alkylation products of the oil obtained by naphtha steam pyrolysis (RPO)

Abstract

In the presence of Friedel–Crafts acids, residual pyrolysis oil (RPO) [Ullmann's encyclopedia of industrial chemistry, 4th ed. 1993: A23; p. 89; Kirk-Othmer encyclopedia of chemical technology, 3rd ed. 1990: 13; p. 717] is easily converted to a petroleum aromatic resin (PAR) [Jeremic K, Jovanovic JA. Erdoel and Kohle, erdgas petrochemie, 1993: 46; 430–434]. By using HPLC chromatography, GC-MS, HPLC-MS and APCI-MS/MS techniques and the reaction of indene and naphthalene in the presence of boron trifluoride for comparison, it was proved that the PAR sample investigated in this work represented a mixture of the components that remained from RPO, an oligomer with dimers, trimers and tetramers in, respectively, decreasing quantities, an alkylate with naphthalene being the main substrate and a polymer in which products with 7–32 monomer moieties prevailed. The monomers and alkylation agents present in the RPO were identified, as were the components that do not polymerize and could be alkylated. By taking into account all the possible oligomerization products including dimers, trimers and tetramers, both in the form of homopolymers and heteropolymers, and all the possible alkylation products, the molecular weights of compounds expected in the oligomer and the alkylate part of the PAR were calculated. All of them were detected in the PAR by using direct sample insertion APCI-MS/MS analysis. GC-MS and HPLC analysis of the PAR and GC-MS, HPLC and HPLC-MS analysis of a product mixture of the reaction of indene in naphthalene in the presence of boron trifluoride, were accomplished. By using the described analytical procedure, it has become possible to control and manage the reaction of the conversion of RPO to PAR, and to characterize this complex system in a very precise manner.