Kinetic Study On The Dehydration And Condensation Of Acetone To Form Mesityl Oxide And Catalytic Distillation Simulation

One of the effective uses of acetone utilization is the synthesis of methyl isobutyl ketone through a condensation dehydration hydrogenation process.The inter-mediate products,diacetone alcohol and mesityl oxide,in the reaction process have a higher economical values.In this paper,the kinetics of acetone condensation dehydration process was studied when solid cation exchange resin was used as catalyst.The obtained kinetics was applied to the reactive distillation process of the system,and the reactive distillation process of acetone,DAA and MSO in the reaction distillation column was simulated.Firstly,the kinetics of acetone dehydration condensation reaction was studied under laboratory conditions,and the effects of mass transfer resistance,catalyst loading,reaction temperature and initial water content of acetone were investigated.It was found that the temperature had an obvious effect on the reaction rate of acetone.When the temperature increased,the acetone conversion increased at the same time.The addition of water to the acetone inhibits the dehydration process of diacetone alcohol and reduces the conversion of acetone,so the selectivity to diacetone alcohol is increased in the initial stage during the acetone reaction.Then,the reaction kinetics of the dehydration process of diacetone alcohol was investigated by using diacetone alcohol as the reactant,and the most suitable reaction kinetic model was obtained.Finally,the hydrolysis process of mesityl oxide was observed by using mesityl oxide and water as the reactants.The experimental results confirmed that the reaction rate of mesityl oxide hydrolysis process was relatively slow.The stepwise reaction characteristics of the acetone condensation dehydration process were also confirmed by experiments comparing three different reactants.At the end of this paper,the parameters of the kinetic model are obtained by Matlab,which can better predict the experimental results.Reactive distillation has the characteristics of being able to change the equilibrium of the reaction and to remove light and heavy components out of the reaction zone in time.Based on the experimental reaction kinetics model,this paper writes a kinetic subroutine in Fortran language and successfully embeds it into Aspen Plus.Using Aspen Plus to simulate the dehydration condensation of acetone to form mesityl oxide,it was found that the position of the feed stage and the tray catalyst loading had a significant effect on the selectivity of MSO.At the same time,the optimized feed stage,the number of theoretical stage in the reaction section,the number of theoretical stage in the rectifying section,the number of theoretical stage in the stripping section,the reflux ratio and other factors on the conversion of acetone and the selectivity of mesityl oxide were obtained.Increasing the tray catalyst loading can obtain a large amount of MSO products at the bottom of the column.The optimized result is that the acetone conversion rate reaches 99% and the mesityl oxide selectivity reaches 93%.The DAA and MSO products can be obtained simultaneously at the bottom of the column after adjusting the feed stage position and the tray catalyst loading.The introduction of side-stream rectification can obtain pure DAA and MSO products at the bottom of the column.