High Performance Non-Mercury Catalysts for VCM Production: From Theoretical Study to Industrialization

摘要

Acetylene hydrochlorination is the main reaction for the dominant coal based process for VCM (vinyl chloride monomer) production from coal resource in mainland China. The traditional activated carbon based mercury catalyst for this reaction causes severe human damage and environmental pollution. Gold is widely considered as the most active metal for acetylene hydrochlorination reaction and copper is the most common metal with obvious price advantage. These two metals show the best potential as the active component for environmentally friendly non- mercury catalysts. In our study, the performance of Au/Cu catalyst was dramatically enhanced by the introduction of negative ion ligands. KSCN (potassium thiocyanate) was confirmed to significantly enhance the initial activity of the catalyst and TCCA (trichloroisocyanuric acid) was proved to be an effective ligand for preventing Au3+ from reduction by acetylene, leading to longer catalyst lifetime. The findings were successfully verified by over 18000 hour’s industrial plant-trial evaluation. Abundant characterization methods including TEM, XRD, TPR, XPS, ICP-AES and nitrogen adsorption-desorption were carried out to reveal the factors which affect the activity and stability of catalysts. Meanwhile, DFT calculations also gave atomic level understanding of the function of ligands. The experiment and DFT results provide reasonable methodology for the design of high performance non-mercury catalysts in acetylene hydrochlorination process, which demonstrate enormous potential for the industrialization in PVC (poly vinyl chloride) industry.