Preparation Of Norbornene And Vinyl Norbornene In A Microreactor

Norbornene(NB)and vinyl norbornene(VNB)as norbornene derivatives,have a wide range of application.NB can be used for the synthesis of cycloolefin copolymer(COC).COC are widely used in optical,electronics,and pharmaceutical packaging as its low density,high transparency,low hygroscopicity,high heat resistance and excellent processability.Ethylidene norbornene(ENB)is an isomer of VNB and the best third monomer for the synthesis of ethylene propylene diene elastomers(EPDM),which could enhance the vulcanization rate of ethylene propylene rubber.In the current mainstream processes,NB and VNB are synthesized by Diels-Alder reaction between dicyclopentadiene(DCPD)and ethylene(E)or 1,3-butadiene(BD),which involves high temperature and high pressure,exothermic reaction,multiple by-products.Reaction conditions are out of control easily.These can cause the unstabitily of product's quality,even safety accidents.However,the use of microreactor to synthesize NB and VNB can further strengthen the reaction,optimize the process conditions,control stability and improve the safety of continuous production.In this thesis,the kinetics of depolymerization of DCPD was studied,followed by the synthesis of NB and VNB in a continuous flow microreactor.The kinetics of depolymerization of DCPD was first studied.Endo-DCPD was dissociated into CPD,and CPD was dimerized into endo-DCPD and exo-DCPD.The following reactions between CPD with endo-DCPD or exo-DCPD generate TCPD.The complete kinetic parameters are obtained,and the regression correlation coefficients are above 0.94.Secondly,NB were synthesized by reaction between DCPD and E in the microreactor.Effects of reaction pressure,feed flow rate,DCPD concentration,reaction temperature and feed molar ratio(E/CPD)on synthesis of norbornene have been investigated.Increasing the feed molar ratio E/CPD and the reaction pressure,the molar ratio E/CPD in the liquid phase can be improved.As a result,the selectivity of the reaction can be improved effectively.The selectivity is 99%,conversion is near 98%under the optimal experimental conditions.VNB were synthesized by reaction between DCPD and BD in the microreactor.There are more side reactions in VNB process than that in NB process.Therefore,the primary purpose is improving selectivity.The effects of pre-heating temperature,reaction temperature,residence time,feed molar ratio(BD/CPD),DCPD concentration and reaction pressure were systematically studied.The selectivity of BD reach 58-62%,and conversion of BD is 41-66%;the selectivity of DCPD can reach 49-61%,and the conversion of DCPD is 9-17%under the optimal experimental conditions.