Preparation Of CuO-ZnO Catalyst And Study On The Performance Of Formaldehyde Acetylene

1,4-butynediol?BYD?is an important organic chemical product widely used in chemical,pharmaceutical and agricultural fields.In recent years,with the rapid development of its downstream products,the demand for BYD has increased year by year and has a good development momentum.At present,the industrial production of BYD uses the alkyne aldehyde method?Reppe?process using a copper-based catalyst based on formaldehyde and acetylene.The copper-based catalyst needs to be activated in situ in the reaction,first reducing Cu²⁺ to Cu⁺,then Cu⁺ and acetylene to form active species acetylene cuprous.The core problem of this process is to promote the efficient conversion of Cu²⁺ to Cu⁺ species and to inhibit the production of Cu,an excessive reduction product.In this paper,based on the presence of Bi₂O₃,Fe₃O₄,MgO,TiO₂ and other additives or carrier-modified copper species,CuO-ZnO binary catalyst system was prepared.The effect of CuO-ZnO interaction on the existence state and transformation process of CuO was discussed.The theory of Cu⁺-acid-base synergistic catalysis of formaldehyde acetylation was proposed.Provide theoretical basis for research and development of new and efficient acetylation catalysts.The main findings of this paper are as follows:1?CuO-ZnO catalysts were prepared by coprecipitation method with NaOH,Na₂CO₃ and NaHCO₃ as precipitants.It was found that different precipitants had a great influence on the dispersion of active components in the catalyst.Further,different catalytic activities are exhibited in the reaction of formaldehyde acetylation to 1,4-butynediol.CuO-ZnO solid solution is formed in the catalyst prepared by using Na₂CO₃ as precipitant,which improves the dispersion of CuO and the stability of Cu⁺ under reducing atmosphere.After activation,more active species of copper acetylide can be formed,showing the best acetylation reactivity and 1,4-butynediol selectivity.2?A series of CuO-ZnO catalysts with different structures were prepared by changing the calcination temperature.The characterization and evaluationresults show that in the preparation process of the catalyst,when the calcination temperature is too low,the decomposition of the catalyst precursor is not complete,which will affect the formation of the active center of the catalyst and affect the catalytic performance of the catalyst;when the calcination temperature is too high,some catalysts will agglomerate and sinter,affecting the uniform dispersion of CuO and ZnO,and thus reducing the activity of the catalyst.When the calcination temperature is 350 ?,the catalyst forms a solid solution of CuO-ZnO,and a strong interaction between CuO and ZnO is produced,which improves the dispersibility of CuO and converts CuO into a highly dispersed Cu⁺ species.At the same time,the catalyst exhibits a suitable surface acidity and alkalinity,and it is presumed that Cu⁺-acid-base synergistic catalysis exists,and the catalyst exhibits the best acetylation performance.