Analysis of Organometallic Gasoline Additives with the Composition-Explicit Distillation Curve Method

Problems associated with pre-ignition of fuel in a spark-ignition engine have been documented for many years and include poor performance and structural damage in engines. These problems were addressed in the past by adding organometallic additives, such as tetraethyl lead (TEL), to the fuel. While this additive is banned, others are permitted in some jurisdictions. Two such additives are ferrocene (FC) and methylcyclopentadienyl manganese tricarbonyl (MMT). In this paper, we apply the advanced distillation curve approach to the analysis of these two additives (at concentrations of 20 and 40 mg/L) in a typical gasoline. We observe that neither additive affects the volatility of gasoline until the 55% distillate volume fraction. Subsequent to this fraction, we note temperature departures from the base gasoline that progress from 1 to 7 degrees C for FC and from approximately 1 to 4 degrees C for MMT. We further note, with the composition-explicit data channel Idle advanced distillation curve (ADC), that the additives are not found in the distillate until after the 55% distillate volume fraction and that the concentration in the distillate increases as the distillation proceeds to completion.