|
In this paper, preparation of antioxidant4020was studied by hydrogenation, using RT base and MIBK as raw material, Pt/C as catalyst.The most suitable support was selected from four kinds of commercial actived carbon.Pt/C catalyst was prepared by immersion-reduction.Effects of preparing conditions on catalyst were investigated by catalytic activity evaluationtest and characterizations such as TEM, XRD, BET, ICP and XRF.The result obtained indicated that surface chemical property of actived carbon could be improved by oxidation;Pt particles obtained by equivalent immersion had a terrible loading condition with bad catalytic activity;Pt content was not linear with reaction time, extortionate Pt content having a bad influence on electivity;Sn was advantageous to the catalytic stability. Optimized preparing conditions were oxidation by20%nitric acid, excessive immersion, Pt content3%, immersion with SnCl2.Process of preparing antioxidant4020by hydrogenation was studied using Pt/C catalyst with3w%Pt content. Effects of reaction conditions such as catalyst amount, ketone amine ratio, reaction temperature and pressure, stir speed, on hydrogenation were investigated.The experimental results indicated that different conditions had different influence on hydrogenation. The optimized preparing conditions were catalyst amount1w%, ketone amine ratio3.5:1, reaction temperature120-130℃, H2pressure3-3.5Mpa, stir speed600-700rpm.The catalyst reuse experiment was carried out using the optimized preparing conditions.The catalytic stability and useful life were investigated. The catalyst used52times altogether,with new catalyst adding8times.Catalyst using in the experiment amounted tol.68g(0.84g dry).The content of4020stayed above98.5%,while the crystallization point stayed above46℃,with a good quality. MIBK reuse experiment was studied. The experimental result indicated that MIBK reused had noinfluence on hydrogenation. The fresh and used catalysts were analyzed by characterizations such as TEM, XRD, MSA, BET,ICP and DTA, to investigate the main cause of deactivation.The analysis results indicated that the loading condition of catalyst deactivated had no change,while the MSA and BET data decreased obviously. The main reason of deactivation was organics and carbon deposition covering the Pt active site and pores on the carbon.The catalyst deactivated was regenerated with different methods. The result indicated that the best regeneration effect was obtained by combination of supercritical CO2and MIBK washing.
|