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Study On Fixed-bed Process Of Highly Efficient Epoxidation Of Allyl Chloride With Hydrogen Peroxide Over Ti-MWW

Posted on:2010-03-11Degree:MasterType:Thesis
Country:ChinaCandidate:M K YaoFull Text:PDF
GTID:2121360275993957Subject:Physical chemistry
Abstract/Summary:PDF Full Text Request
Epichiorohydrin as the third largest amount epoxide is the most important raw organic material for epoxy resin.High temperature chlorination of propylene and allyl acetate method are the two main ways for producing epichiorohydrin at present,but these traditional methods had a lot of shortcomings such as byproduct and environment pollution.Ti-MWW/H2O2 could be the potential way to solve these problems.This dissertation focused on the epoxidation of allyl chloride over Ti-MWW in the fixed bed.Ti-MWW was an active and selective catalyst for olefine epoxidation.We studied the rule of this reaction from the parts of the physical and chemical character of the catalyst and the reaction parameters.And we did some beneficial exploration on the deactivation of catalyst.All the work provided reliable basis for the industrial application of Ti-MWW.In the first part,we designed the Ti-MWW/H2O2 fixed bed catalytic system according to the analyse of thermodynamic and kinetics of the epoxidation of allyl chloride.We did research on the rule of this reaction from the parts of the physical and chemical characters of the catalyst(Si/Ti molar ratio) and the reaction parameters (temperature,solvent,substrate WHSV and molar ratio between different substrates) in detailed.The study showed the H2O2 reactive action was the control step for the epoxidation of allyl chloride.We got the appropriate parameters for this catalyst system and made clear the reaction pathway.In the second part,as the result of H2O2 reactive action was the control step,we studied the decomposition of H2O2 in this reaction system from the parts the physical and chemical character of the catalyst(different amount and state of Ti in the catalyst, different components in the catalyst and different type titanium silicate molecular) and the reaction parameters(the effect of H2O2 concentration and WHSV,different reactor).The results showed the H2O2 decomposed more quickly as the H2O2 contact the catalyst longer.The framework Ti and acid center in Ti-MWW were the main reasons causing the decomposition of H2O2.Finally,various measurements(XRD,SEM,BET,FT-IR,UV-Vis,ICP,TG) were adopted to study the deactivation reasons of the catalyst.The most important reasons of the inactivity of the catalyst are follows:1.the deactivation caused by carbon deposit was reversibility;2.the deactivation caused by the content of Boron in the molecular sieve decreasing was irreversibility that cause the increasing of vacancy in the catalyst.A novel secondary synthesis caused a structural rearrangement of Ti-MWW framework could revive the catalyst.
Keywords/Search Tags:Titanium silicate molecular sieves, Ti-MWW, allyl chloride, hydrogen peroxide, epichiorohydrin
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