Synthesis And Catalytic Performance Of Carbon Supported Ruthenium Catalyst For Acetylene Hydrochlorination

Polyvinyl chloride?PVC?is one of the most used engineering plastics in the world,which is widely used in various fields.With the requirements of environmental protection,mercury free catalysts have become the key issue to the development of the acetylene hydrochlorination industry.Herein,the effects of the loading of ruthenium,preparation method,ligand modification and adjustment of defective carbon structure on catalytic performance of carbon supported ruthenium catalyst and the structure-activity relationship between the electronic structure of ruthenium ion and the catalytic performance of acetylene hydrochlorination were studied.And the deactivation mechanism and longevity of carbon supported ruthenium catalyst in acetylene hydrochlorination were also studied.The following conclusions were obtained:?1?The relationship between the catalytic activity and the loading of ruthenium in the acetylene hydrochlorination reaction was correlated.Within the range of the Ru loading of 0.01 to 0.2 wt.%,the acetylene conversion and ruthenium loading increases linearly.The deactivation rate of carbon supported ruthenium catalyst accelerated with the increase of the ruthenium trichloride loading,and the acidity of the catalyst also increased,indicating that the deactivation of the activated carbon supported ruthenium catalyst was found to be due to the acidity of ruthenium trichloride.?2?RuCl₃-A/AC was prepared by impregnation precipitation method,compared with RuCl₃/AC catalyst,the stability of RuCl₃-A/AC catalyst was significantly improved.Through NH₃-TPD and TG characterization,it confirms that the acidity of RuCl₃-A/AC decreased and the coke deposition was inhibited.The stability of the catalyst increases with the increase of p H value of the immersion precipitation solution.The catalyst prepared by hydrogen peroxide treatment can also reduce the acidity of the catalyst,and ruthenium carbonyl as the precursor catalyst,the performance of the catalyst is improved.?3?The electronic structure of carbon supported ruthenium catalyst was regulated by the coordination strategy and the Ru-Thi/AC catalyst with thiourea as ligand shows the best catalytic performance with high TOF value and stability.The experimental results indicate the synergistic effect of ruthenium ion and ligands can improve the catalytic performance of acetylene hydrochlorination The TOF value and apparent activation energy of carbon supported ruthenium catalysts in the acetylene hydrochlorination reaction are linearly related to the binding energy of ruthenium ions.Investigating the catalytic performance of carbon supported ruthenium catalysts with various valence states,and the Ru²⁺-P?Cl?/AC catalyst shows the best activity and stability.?4?The effects of oxygen functional groups and defects on the catalytic performance of carbon supported ruthenium catalysts were also investigated.The stability and activity of defective carbon supported RuCl₃/AC-D catalyst is significantly improved compared with RuCl₃/AC.The DFT and experiments results revealed that the electron cloud density of ruthenium ions is increased by the strong interaction of defective site of carbon with ruthenium ions,thereby reducing the desorption energy barrier of vinyl chloride and increasing the activation energy of acetylene polymerization to form coke deposition,which plays a significant role in inhibiting coke deposition.However,the interaction of RuCl₃ with oxygen functional groups on the surface of the support increases the acidity of the ruthenium catalyst,which leads to rapid deactivation of the catalyst.