Font Size: a A A

Study On Spray Reactor And Displacement Reaction Of High Carbon Alkylaluminum

Posted on:2003-06-03Degree:DoctorType:Dissertation
Country:ChinaCandidate:B ZhouFull Text:PDF
GTID:1101360092480343Subject:Industrial Catalysis
Abstract/Summary:PDF Full Text Request
Linear low a-olefms are important comonomer of polyethylene and materials of fine chemicals but there is no modern oc-olefin industry in our country now. In this dissertation, a displacement reaction and technique of high carbon alkylaluminium with ethylene to prepare a-olefins are investigated in order to form national patent technique.A new synthesis method of a-olefins using spray reactor through continuous displacement reaction of high carbon alkylaluminium with ethylene is studied.The optimum conditions are : reaction temperature=260℃, reaction pressure=1.0MPa, preheating temperature of high carbon alkylaluminium =160癈, mole ratio of ethylene to high carbon alkylaluminium =50. The operation conditions have been improved hi comparison with two-step process of Ethyl Co.. The results show that the single process conversion of high alkylaluminium is more than 85%. The selectivity of a-olefins is more than 99% and the isomerization of a-olefms is not found namely.A new convenient analysis method for conversion and isomerization of this complicate displacement reaction has been established.A new type of double-dish slump film separator and technique, which can separate gas-liquid emulsion , has also been designed. The results show that top ethylene contains only 1% butene, and bottom liquid phase contains less than 1% ethylene. The separator has a large flash area, structure with reason and easy production. It is suitable for separating highviscosity gas-liquid emulsion.A mathematic model of spray reaction has been established through analyzing masstransfer and reaction process of liquid droplet. The model was solved with finite differential method. The profiles of reactant concentration in liquid droplet on set time are established. The effect of droplet radius and reaction time on average conversion is found. The calculation results are in agreement with experimental data. The droplet size is the main factor to conversion.The parameters of pneumatic atomizer have been calculated, the results show that theconversion increases with the decreasing of liquid droplet radius. The atomization process of spray reaction is stable.It is the first time to synthesize of 2,4-dihydroxybenzic acid using new spray process. The yield of 2,4-dihydroxybenzic acid reaches 38.8% on 30-40 second reaction times and have reached 47.7% after tri-time spray which is better than interrupted reaction with the yield of 41.6% on I hour reaction times.The results prove that the spray reaction technique is effective for middle and fast rate reaction controlled by diffusion of gas-liquid. The calculation results anastomose experimental data and prove the reliability of the model again.The catalytic performance of cobalt complexes which contain mono- or bidenate phosphorus, nitrogen ligand on displacement reaction have been studied. The results prove that they are efficient catalysts. The optimum conditions are : reaction temperature=130癈, reaction pressure=1.4Mpa, single process conversion of hign alkylaluminium is more than 82%. The catalytic performance of nickel analogues are also good.The application of these complexes on displacement reaction has not been reported.The kinetics on the displacement reaction of tri-isobutyl aluminum with ethylene catalyzed by zerovalent cobalt complex has been studied. The kinetics equation is r=1.4 X 106 [R3Al][Cat][PC2H4].The activation energy for this reaction is Ea = 71.9kJ/mol.The mechanism of displacement reaction catalyzed by cobalt complexes is proposed. Such work has not been reported.
Keywords/Search Tags:α-olefins, Displacement Reaction, spray reactor, Reaction kinetics, Mathematical model, double-dish slump film separator.
PDF Full Text Request
Related items