Alkylation of oil extracted heavy fraction by some substrates to decrease the content of dangerous PAH

The study investigated the chemical effects on carcinogenically dangerous compounds of oilextracted heavy fraction with alkylating agents on various catalysts. The oil extracted heavy fraction is a concentrate of polycyclic aromatic hydrocarbons that are of considerable interest for the production of plasticizer oils for tires and rubbers. However, some polycyclic aromatic hydrocarbons are carcinogenically dangerous due to the presence in them of “bay” protons that are active in electrophilic substitution reactions and responsible for DNA mutations. The alkylation process was carried out in an apparatus consisting of a reactor equipped with an overhead stirrer, into the jacket of which a coolant of a certain temperature was fed from a thermostat; the process conditions and alkylating agents varied. In the capacity of alkylating agents, the known reagents were used, available and well-studied, for example mononuclear aromatic compounds: alkenes in the presence of a catalyst (aluminum trichloride), alcohols with the use of a catalyst (zinc chloride), and sulphate turpentine (α-pinene) in the presence of orthophosphoric acid. The action of alkylating agents is to replace the “bay” protons in the polycyclic aromatic hydrocarbon molecules. Replacement of the “bay” protons leads to the transfer of a carcinogenicallydangerous compound into a safe one. After isolating the alkylation product, the content of the “bay” proton and hazardous polycyclic aromatic hydrocarbons has been determined. The reduction in the content of the “bay” protons is typical for all samples. This indicates the implementation of the alkylation reaction. The effect of the nature of the alkylating agent on the final result has been observed. In the reaction products during alkylation with cetyl alcohol with a minimum content of the “bay” proton (0.93 %), the content of the sum of 8 polycyclic aromatic hydrocarbons has decreased by almost 70 %. However, for other alkylating agents, the content of the “bay” proton and polycyclic aromatic hydrocarbons has not changed significantly. On the whole, the shallow alkylation of the “bay” proton is probably connected, on the one hand, with the dependence of the alkylation reaction on the reagents used in the reaction, or rather on its reversibility, the influence of stability of the resulting s-complex (kinetic control), stability of the final products (thermodynamic control); on the other hand, with the influence of the selected substrate, that is, oil extracted heavy fraction, a very viscous liquid even in a solution. The latter circumstance also limits the ability of the alkylation reaction.