The Separation And Recovery Process For The Byproducts Of 1,4-butanediol From Alkyne-Aldehyde Method

The process of synthesizing 1,4-butanediol using alkyne-aldehyde method has successfully achieved industrialization and the whole manufacturing process will produce a lot of valuable by-products.The major context in this paper includes those:firstly,in 1,4-butanediol synthesis process,the main components of by-product at distillation column top have been determined by chromatography and other methods,including methanol,tetrahydrofuran,water,ethanol,?-butyrolactone,acetal and1,4-butanediol.Then,in order to confirm whether it is possible to obtain pure1,4-butanediol by simple distillation,batch distillation and recovery experiment for raw materials was carried out using a small and self-made lab's distillation column.The experimental results showed the purity of 1,4-butanediol can reach greater than98% by simple distillation and there was no condensation reaction for 1,4-butanediol.This provides a direct experimental basis for the future development of industrial separation process conditions and the design of distillation column.In order to provide the basic phase equilibrium data for the precise design of distillation column involved in the separation process,using the improved Rose-Williams equilibrium still,isobaric vapor-liquid equilibrium data for the binary systems of n-butanol + 1,4-butanediol and ?-butyrolactone + 1,4-butanediol under pressures of 30.0,50.0,and 70.0 kPa and 1,4-butanediol + 2-Methyl-2,4-pentadiol under pressures of 40.0,60.0,and 80.0 kPa have been experimentally determined.Additionally,the experimental equilibrium binary data of the three groups systems were examined with the methods of the Herington area test and Van Ness point test for the thermodynamic consistency tests.And then the three of nonrandom activity coefficient models which were two-liquid(NRTL),Wilson,as well as universal quasichemical(UNIQUAC),were selected to correlate the isobaric vapor-liquid equilibrium data.All results have demonstrated that the measured values of the binary systems not only satisfied the thermodynamic consistency tests,but also had a good correlation with the three activity coefficient equations.Based on the experiments and phase equilibrium data analysis,we designed a set of process that used three columns to separate 1,4-butanediol and the useful components.Furthermore,we simulated the calculation results of all streams,sensitivity analysis,feedstage,feed temperature,operating pressure,reflux ratio,stagenumber,diameter and the height of the column of each tower.