What methods are available for estimating vapor pressure?

Methods include: Antoine equation: log(P) = A - B/(T+C), most common, limited temperature range per parameter set. Extended Antoine: additional terms for wider range. Lee-Kesler: generalized correlation using Tc, Pc, omega. Riedel: group contribution method. Wagner equation: high accuracy over wide range, used in databases. Selection: Antoine for quick estimates within range, Wagner for accuracy, Lee-Kesler when only critical properties known. Always verify against experimental data for critical applications. Process simulators use stored parameters.