Gibbs ensemble Monte Carlo method with TraPPE-UA force field was used to study the vapor-liquid phase equilibrium of systems containing crotonaldehyde. To lay the foundation for the vapor-liquid phase equilibrium simulation

quantum chemistry calculations with B3LYP 6-311G (d

p) and MP2 6-31G (d

p) basis sets were firstly performed to obtain the lacking bond parameters and torsional parameters for crotonaldehyde molecular. Based on these parameters

a new TraPPE-UA force field was developed. Vapor-liquid phase equilibrium data of pure crotonaldehyde and its mixture with ethanal were calculated using the new force field and compared with experiment data. The saturated liquid densities of pure crotonaldehyde predicted by the new force field were in close agreement with experimental results

with deviations from 0.28% to 1.23%. This demonstrated that the new TraPPE-UA force field manifested high simulation precision for crotonaldehyde. For the binary system consisting of crotonaldehyde and ethanal

the deviation between simulations and experiments increased with rising temperature

and the minimum and maximum values were 0.13% and 7.44%

respectively.