Research On Vapor-Liquid Equilibrium And Distillation Process Of Methanol-Methylal-2-Butanol-2-(Methoxymethoxy)-butane-Di-sec-butoxymethane System

2-(methoxymethoxy)-butane(SMMB)and di-sec-butoxymethane(DSBM)compounds can be used as important organic solvents and organic synthesis intermediates in the pharmaceutical and cosmetic industries.More importantly,they can be used as environmentally friendly fuel additives,which can improve the combustion performance of oil products and reduce the environmental pollution of automobile exhaust.In this paper,the vapor-liquid equilibrium(VLE)of the quinary methanol-methylal-2-butanol-SMMB-DSBM system was studied.The saturated vapor pressures of SMMB and DSBM at the corresponding temperature were measured,and then the Antoine equation was obtained.Binary isobaric(101.3 kPa)VLE data were measured:methanol(1)-SMMB(2),2-butanol(1)-SMMB(2),2-butanol(1)-DSBM(2)and SMMB(1)-DSBM(2).The thermodynamic consistency test of VLE data was performed by the Herigton area method.Wilson,NRTL and UNIQUAC models were used to correlate the binary VLE data,and the binary interaction parameters and corresponding deviations AAD(T,y1)and RMSD(T,y1)were obtained.The results showed that all the three models were well correlated the experimental data,and the NRTL model was more appropriate.The experimental data showed that the system could form azeotropy at 101.3 kPa.The ternary VLE data of methanol(1)-2-butanol(2)-SMMB(3)and 2-butanol(1)-SMMB(2)-DSBM(3)were also determined,which were predicted by the obtained binary interaction parameters,and the calculated values were in good agreement with the experimental data.N,N-dimethylacetamide(DMAC)was developed as an extractant for the extraction of 2-butanol-SMMB azeotrope.To this end,binary 2-butanol(1)-DMAC(2)and SMMB(1)-DMAC(2)isobaric VLE data and ternary 2-butanol(1)-SMMB(2)-DMAC(3)isobaric VLE data were measured.Wilson,NRTL and UNIQUAC models were also used to correlate the experimental data to obtain the binary interaction parameters and deviations AAD(T,y1)and RMSD(T,y1).The results showed that all the three models were well correlated the experimental data.And the model parameters obtained from the correlation of binary VLE data could predict the VLE data of the ternary system.In this paper,two distillation separation processes were developed based on the results of VLE research with ASPEN PLUS simulation software,which can achieve the azeotropic separation to obtain the target product.The effects of the feed stage,theoretical stage number,and the reflux ratio on the purity,yield and separation energy were investigated.The optimized process parameters of the distillation column were obtained by simulation optimization.The purity of the target product reached 99%(m/m)and the yield was 98%,which established the theoretical foundation for the design of industrial devices.