Trimethyl citrate synthesis, synthesis of triethyl citrate with high purity
In the third and preferred scheme, a prereactor followed by a simple distillation column to remove water is placed ahead of the reactive distillation column. The process design, developed using ASPEN Plus simulation citrate synthesis, is based on laboratory kinetic and thermodynamic studies and pilot-scale reactive distillation experiments.
Three different process schemes were examined.
In the first scheme, only a reactive distillation column is used. A large number of reactive stages is required because of the slow reaction of diethyl citrate to triethyl citrate.
In each configuration, triethyl citrate product yield is maintained above The second uses a prereactor followed by a reactive distillation column. Pilot-scale experiments were carried out in a 5-m glass reactive distillation column; catalyst effectiveness was then determined from ASPEN Plus simulation of pilot-scale experiments using a user-written reaction kinetic module based on activity coefficients.
Comparison of stream compositions and equipment design parameters is provided for the three schemes considered. The effect of ethanol feed position and values of reflux and boilup ratios were also examined.
Because citric acid esterification kinetics are slow, complete conversion could not be obtained in the pilot-scale column. Using parameters determined from simulation of a pilot-scale column experiment, design of a reactive distillation column to completely convert citric acid to triethyl citrate was carried out.