Preparation Of Cobalt-Based Nanocatalyst And Their Catalytic Performance In Transformation Of Aromatic Compounds

Developing an efficient and green chemical industry by improving synthesis conversion efficiency through the use of efficient catalysts.It is an urgent need to cope with resource shortage and environmental pollution in today’s world under the concept of sustainable development.Therefore,developing efficient,stable,and low-cost catalysts is of great practical significance.This paper prepared cobalt based nanocatalysts using a strategy of 2-methylimidazole induced hydrolysis.The main research content is as follows:（1）Co₂Ni-LDH has efficient catalytic performance for the oxidation of ethylbenzene:Using Co（NO₃）₂ and Ni（NO₃）₂as metal salts and 2-methylimidazole as ligand,Nanoflower like Co Ni-LDH（layered double hydroxide）nanomaterials with different metal ratios were prepared by solvothermal method.Co₂Ni-LDH has the highest M-O content and Co³⁺ratio.Thereby,Co₂Ni-LDH shows the highest catalytic activity for the oxidation of ethylbenzene.Meanwhile,Co₂Ni-LDH can also catalyze the oxidation of other organic compounds containing benzyl C-H bonds,generating corresponding carbonyl products.（2）CoMnO_xcan catalyze the oxidation of benzyl alcohol under mild conditions:Preparation of 2D（two-dimensional porous）Co Mn-LDH nanosheets by sol-gel method,2D structured CoMnO_x nanomaterials prepared by calcination in a muffle furnace.The experimental results indicate that in CoMnO_x nanomaterials,the presence of both Co²⁺/Co³⁺and Mn²⁺/Mn³⁺,as well as abundant surface adsorbed oxygen,is beneficial for the oxidation reaction to proceed.The CoMnO_x catalyst can efficiently catalyze the occurrence of benzyl alcohol and alcohol compounds with other active groups under O₂ conditions,generating corresponding aldehyde compounds.（3）α-Co（OH）₂nanosheets loaded with Au nanoparticles catalyst for alkyne silica-hydrogen reaction:NH₄Au Cl₄ was used as the active metal precursor to prepareα-Co（OH）₂nanosheets loaded with Au nanoparticles catalyst（Au/α-Co（OH）₂）.The Au nanoparticles with a very small loading（only 0.34 wt%）are the active center of the catalyst,and this nanomaterial catalyst has excellent catalytic activity for the silyl hydrogenation of alkynes.Phenylacetylene was used as the reaction substrate,and the reaction conditions such as temperature,solvent,and time were screened.The selectivity of the conformational product ofβ-（E）was up to 94.3%under the optimal reaction conditions.Aromatic alkynes,aliphatic alkynes and heterocyclic-containing alkynes with different substituents can be converted to the correspondingβ-（E）-based alkenesilicates with high activity and selectivity when Au/α-Co（OH）₂ is used as a catalyst.