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Research On Reaction Engineering Of Producing Alkynols With Reppe Method

Posted on:2015-08-20Degree:MasterType:Thesis
Country:ChinaCandidate:W B JiaFull Text:PDF
GTID:2271330470460789Subject:Chemical Process Information Engineering
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Propargyl alcohol (PA) is an important organic chemical raw material which is widely used as an intermediate in pharmacology and pesticides, brightening agent in nickel plating, rust remover in steel industry and high-performance acidulating corrosion inhibitor in petrochemical industry. Market demand for PA is continuously increasing with more and more new downstream products being developed. There is only one industrial method for synthesizing PA which was invented by a German chemical engineer, Reppe. In this method, which is also known as Reppe method, formaldehyde (FA) reacts with pressurized acetylene with copper acetylide as catalyst,2-butyne-1,4-diol as main product and propargyl as by-product. 2-Butyne-1,4-diol (BYD) is also an important chemical intermediate while its added value is not as high as that of PA.There are several modified versions of Reppe method. All of them work under low pressures and take BYD as the target product. Up to now, all available kinetic research on Reppe reaction was focused on low pressure processes and no research on studying the consecutive reaction separately and analyzing the synthesis mechanism of PA was published, which had become a key factor baffling the development of PA synthesis process.This thesis introduced a cost-effective and high-efficiency analysis method for precisely determining composition of Reppe reaction product solution. GDX-401 was used as a support to prepare a stainless steel packed chromatographic column without coating stationary liquid. We accurately analyzed the contents of PA and BYD in Reppe reaction solution by using gas chromatograph and FID detector.By setting mass ratio between Cu/Bi catalyst and formaldehyde solution at 0.25, temperature ranging from 70 to 110℃ and total pressure ranging from 0.5 to 1.3 MPa, this research carried on a series of experiments with a stainless steel autoclave and observed how concentrations of FA, PA and BYD changed by time. Afterwards, reaction orders of all reactants in the consecutive reaction were determined and rate constants of each reaction under different conditions were attained. We calculated activation energies and pre-exponential factors of each reaction and successfully built up the complete microkinetic model for the whole reaction. This model was verified by experimental results with mean relative errors of FA, PA and BYD concentrations at 2.951%,4.905% and 5.427%, respectively. By using the above model, we disussed the very factors which influenced the yield of PA and quantificationally studied effects of reaction temperature and pressure on yield of PAWhat’s more, by using the above kinetic model and axial dispersion model, we had a simulation of Reppe reaction in a fixed-bed column reactor and studied how the value of Pe would influence the reaction result, which laid a foundation for applying oscillation into fixed-bed reactor. On the basis of achieved knowledge about kinetics, this thesis used industrial-scale catalyst to carry on Reppe reaction in a packed-bed oscillatory-flow reactor and studied different effects of catalyst’s internal diffussion on the two reactions of the consecutive reaction, which supplied valuable information for further research on reaction engineering of Reppe process.
Keywords/Search Tags:Propargyl alcohol, 2-Butyne-1,4-diol, Reaction kinetics, Reactor simulation, Axial dispersion model
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