Screening Of 1 - Butene Hydroformylation Reaction Ligand And Optimization Of Technological Conditions

Hydroformylation of1-butene to synthesize pentanal is one of effective ways for the comprehensive utilization of C4resources. Pentanal can be used to further synthesize pentanol, pentanoic acid, amylamine,2-propylheptanol (2-PH), and other chemicals.2-PH can be used to further synthesize environmentally friendly bis(2-propylheptyl) phthalate (DPHP). Hydroformylation of butene is a new method for the comprehensive utilization of butenes and has significant importance in improving utilization of olefins.In this thesis, homogeneous catalysis system for hydroformylation of1-butene was studied in an intermittently stirred reactor. The precursor of catalyst is dicarbonyl(2,4-pentanedionato)rhodium(I).1) First, the ligands such as triphenylphosphine(TPP),1,2-Bis(diphenylphosphino) ethane (DPPE),1,3-bis(diphenyphosphino)propane (DPPP),1,4-bis(diphenylphosphino)butane (DPPB),2,2’-bis(diphenyphosphinomethyl)-1.l’-biphenyl (BISBI) and6,6’-[(3,3’-Di-tert-butyl-5,5-dimethoxy-1,1’-biphenyl-2,2’-diyI)bis(oxy)]bis(dibenzo[d,f][1,3,2] dioxaphosphepin)(Biphephos) were screened. It was found that the dual phosphite ligand, biphephos, has the best effect for the hydroformylation of1-butene, compared to any other single ligand. The optimal reaction conditions for biphephos are:the molar ratio of phosphorus and rhodium(P/Rh) is8:1; rhodium concentration is200～250ppm; the molar ratio of substrate and catalyst(S/C) is1800; reaction temperature is110℃; reaet ion pressure is2.0MPa; the molar ratio of hydro gen and carbon monoxide (H2/CO) is2:1; reaction time is1h. By using the as-prepared catalyst with biphephos as ligand in the hydroformylation of1-butene, the TOF value of the reaction reached up to1370.5b-1and the molar ratio of valeraldehyde and isovaleraldehyde(Trad n/i) was23.0.2) We focused on the investigation on the effects of combinatorial ligands on the hydroformylation of1-butene. The effects of ligand combinations during TPP, DPPE, DPPP, DPPB, and Bphephos on the reaction activity and selectivity were studied. It was found that the combined DPPB and Bphephos ligands have the best effect for the hydroformylation of1-butene, compared to other combined ligands. The optimal ratio of the catalyst system was determined by using orthogonal test. The optimal rhodium concentration is150ppm; the optimal molar ratio of DPPB, Biphephos, and Rh is8:8:1. By using the as-prepared catalyst with DPPB and Biphephos as combined ligands in the hydroformylation of1-butene, the optimal reaction conditions for the hydroformylation of1-butene are following. Reaction temperature is110℃; reaction pressure is2.5MPa; the molar ratio of hydrogen and carbon monoxide(H2/CO) is1:1; s/c is2000. Under the optimal reaction conditions, TOF value of the hydroformylation reached up to1572.1h-1and the n/i was86.2after the hydroformylation underwent for1h.The as-synthesized rhodium catalyst system with DPPB and Biphephos as combined ligands for the hydroformylation of1-butene can significantly improve the molar ratio of valeraldehyde and isovaleraldehyde, increase the selectivity of pentanal, and maintain the good reaction activity. Compared with the catalyst system with TPP and Biphephos as combined ligands in CN101332437A, under the equivalent condition of the molar ratio of valeraldehyde and isovaleraldehyde, the rhodium concentration reduced from250ppm to150ppm, cost savings. It provides a potential hydroformylation catalyst system which will have the industrial application prospects.