Design Of Cu-IL Active Phases And ILs-derived Carbon Materials For Acetylene Hydrochlorination

Polyvinyl chloride?PVC?is one of the most important plastic materials,which is polymerized from vinyl chloride monomer?VCM?.In China,the production of VCM is mainly based on acetylene hydrochlorination using Hg Cl₂/AC catalyst,which is harmful to environment and organisms.Thus,the development of environmental and biological safety catalysts is urgently needed.In the past decades,studies have focused on noble metal catalysts,e.g.Au,Ru and Pd,which are economically costly due to the manufacture cost and the replacement cost caused by the deactivation and frequent replacement of catalysts.To enhance the stability of noble metal catalysts,ionic liquids was introduced in catalysts via supported-ionic-liquids technology,which has been proved that furnishing excellent properties in improving the durability of metal catalysts,however,deactivation still exist and impeding the large-scale application.Therefore,it is of great significance to develop base-metal or metal-free catalysts as alternatives for industrial catalysts.Based on this,the work of this paper begins in three directions:1.First direction is the introduction of various ionic liquids in typical carbon-supported Cu-based catalysts.We mainly screen out the ionic liquids based on the catalytic performance of through the modification of anions and cations.Among investigated Cu-IL/AC catalysts,10Cu-[Hnmpo]H₂PO₄/AC-2 exhibits better catalytic performance,achieving 89.16%acetylene conversion and>99%selectivity under T=150?with GHSV?C₂H₂?=50 h^-1.Furthermore,a series of characterizations such as XRD,XPS,TG,TPD,TPR were performed to investigate the promotion mechanism combined with DFT simulations.2.Second direction is on the basis of the active phase construction of Cu and ionic liquid on carbon support,the cooperative ionic liquid and Cu-BTC MOFs with fixed and uniformly distributed active sites in bulk phase.Imidazolium ionic liquids with three different anions were investigated,and it is found that Cu-BTC supported[BMIm]Cl furnishes better catalytic performance with 55.6%acetylene conversion and more than 98%selectivty to VCM at T=150?and GHSV?C₂H₂?=120 h^-1.Meanwhile,the results of XRD,XPS,SEM,EDS,TEM and FT-IR characterization indicates that the introduction of[BMIm]Cl can stabilize Cu²⁺in Cu-BTC,in turn,Cu-BTC can increase the thermostability of this kind of ionic liquid,the synergism between IL and Cu-BTC can improve their adsorption performance of acetylene and hydrogen chloride,which make Cu-MOFs act as a kind of excellent host.3.A series of ILs-derived boron carbon materials were synthesized and investigated in catalyzed acetylene hydrochlorination.A kind of mixed ionic liquids containing[EMIm]NTf₂and[EMIm]TPB was prepared into a kind of carbon-based catalyst with a large number of boron-doped-carbon-nanodots embed in it via carbonization method.At the same time,a batch of B-CNDs-g series of materials synthesized from graphene and B₂O₃were performed as comparison.Surprisingly,it was determined that BC₃species was the active sites which is linearly related to the catalytic activity.Moreover,five possible surface adsorption sites of B-CNDs include p-G,g-B,-BCO₂,-BC₂O and-BC₃were investigated in the reaction path way based on adsorption and desorption behavior to products and reactants via DFT calculation.Finally,the local heterogeneous electrostatic potential and the good distortion resistance that resulting from the BC₃insertion in layered carbon materials was response to the interesting catalytic properties of B-CNDs catalysts.