Processes for reducing the mutagenicity of refinery streams and coal tars via <= C3-alkylation

Processes for reducing the mutagenicity of refinery streams and coal tars c ontaining polynuclear aromatic compounds (PAC) are described. The investiga tion was based on the supposition that the reduced mutagenic activity of so me refinery streams (relative to cracked stocks and coal tars) was related to the degree of alkylation of the PAC stream components. Much of the devel opment work was carried out using benzo[a]pyrene (BaP) as a model surrogate for the PAC responsible for the mutagenic potency of refinery streams and coal tars, Using Friedel-Crafts procedures, the mutagenic activity of a num ber of refinery streams and coal tar products was significantly reduced or completely eliminated when reacted with a C3-, C4-, or CS-alkylating agent. Recent work has turned toward adapting the laboratory-based chemistry to r efinery-based chemistry using heterogeneous catalysis (acid clay/pillared c atalysts/zeolites).