Study Of The Nickel Catalysts Supported On Carbon Nanotubes For Methanol Carbonylation

The carbonylation of methanol is affected by the disadvantages associated with a highly corrosive recation medium due to the use of iodide as promoter, difficultly separating products and low selectivity of carbonyl products, especially AcOH, on Ni/AC catalysts. In order to improve the current technology, Ni/CNTs catalytic system was investigated for the vapor-phase carbonylation of methanol under atmospheric pressure. In the paper, a series of Ni/CNTs catalysts were prepared and studied, then bimetal catalysts were carefully examined and compared, lastly tri-metal catalysts were studied tentatively. The studies of this thesis mainly include the following aspects:1 , Carbon nanotubes in 10mol HNO₃ was refluxed, and carbon nanotubes was filtered and rinsed, then add them into toluene and NaHCO₃ solution, following stirred, sonicated, filtered and rinsed, finally Drying overnight in a thermostatted oven at 383K, nickel catalyst supported the carbon nanotubes attained optimal activity of methanol carbonylation.Too strong and too light concentration of HNO3 are not good for improving catalytic activity on methanol carbonylation, the results of the experiment are the same with the results of TEM.2 , Ni/CNTs catalysts were prepared by a impregnation method to impregnate carbon nanotubes with methanol solution of nickel or other metals, following step drying. Then appropriate method of heat and reduction activation treatment were ascertained, then optimal temperature of heat (N2) and reduction activation(H₂) treatment were respectively 300℃ and 500℃.3, Under the optimal reaction conditions: O.lMPa, 280℃, CO/methanol=2/1, GHSV is 3000/L(kgcat.h)^-1³600/L(kgcat.h)^-1 and the content of Ni is 8wt.%, a optimal activity is achieved. The conversion of methanol reaches 32.8%, the selectivity of AcOH is more than 33.17% and the yield of AcOH is 10.88%.4, The selectivity of AcOH on Ni/CNTs catalyst is nearly twice of that of Ni/AC catalyst while the conversions of methanol on both catalysts are to some tune,possibly because of giving electron of carbon nanotubes function and comparatively weak between activity ingredients resulting in reduction of NiO. 5 > A series of Ni-based bimetallic catalysts were investigated under atomospheric vapor-solid phase. It is revealed that the additive of La> Mo and Cu into Ni/CNTs facilitated the reaction while Zn and Co restrained it. The AcOH selectivity on Ni-Mo/CNTs catalyst is elevated farthest (37.52%); the methanol conversion on Ni-Cu/CNTs catalyst is the most (36.1%).6> Ni-Mo/CNTs catalyst prepared by coimpregnation has better carbonyl activity, and the content of Ni and Mo is 7.0wt. % and 2.1wt.%; Ni-Cu/CNTs catalyst prepared by stepwise impregnation has better carbonyl activity, and the content of Ni and Cu is5.0wt.% and 1.5wt.%.7, The simultaneous addition of Mo and Cu to Ni/CNTs has not elevated the activity of methanol atomospheric carbonylation compared with Ni/CNTs.