Evaporation of methyl- and dimethyl-substituted malonic, succinic, glutaric and adipic acid particles at ambient temperatures

Abstract

Vapor pressures of five methyl-substituted dicarboxylic acids are inferred from measurements of evaporation rates of sub-micron particles using the TDMA technique at ambient temperatures. Vapor pressures obtained are: log(pmethyl-malonic0/Pa)=-5538K/T+15.5, log(pdimethyl-malonic0/Pa)=-6195K/T+17.2, log(p2-methyl-succinic0/Pa)=-4800K/T+13.3, log(p2,2-dimethyl-succinic0/Pa)=-3515K/T+9.0, log(p3-methyl-glutaric0/Pa)=-3173K/T+7.5, log(p3,3-dimethyl-glutaric0/Pa)=-3138K/T+7.6, log(p3-methyl-adipic0/Pa)=-11227K/T+33.8. These vapor pressures are compared with available literature data and with vapor pressures of the un-substituted acids. Our results demonstrate that molecular structure is important for solid state vapor pressures of secondary organic aerosol components at ambient conditions.