Preparation Of CuO/AC Catalyst Performance In Formaldehyde Ethynylation

1,4-Butynediol（BYD）is an organic compound containing multiple functional groups such as C≡C and C-OH,which has important value of industrial application.BYD was synthesized by Reppe method,that is,formaldehyde and acetylene were used as raw materials and formed on the copper-based catalysts.At present,copper-based catalysts used in ethynylation of formaldehyde reaction often use oxides as carriers and additives to improve the dispersion of active species and adjust the electronic valence of Cu species.In the aqueous environment of BYD synthesis,the oxides are prone to hydrate causing catalyst destruction and remaining in the reaction solution,which requires additional detachment devices and increased equipment investment.In this work,CuO/AC catalysts were designed and synthesized using chemically stable activated carbon as the carrier,and the effect of the carbon carrier on ethynylation of formaldehyde was investigated to provide a reference for the development of efficient new catalysts for ethynylation of formaldehyde.1.CuO/AC catalysts were prepared by impregnation method using activated carbon as the carrier,and the additives Mg,Fe and Bi were introduced to modify the catalysts,and the structure-activity relationship between the structure of the catalysts and the ethynylation of formaldehyde performance was investigated.It was found that the carbon carrier promoted the dispersion of active components and the addition of additives improved the catalytic performance of the catalysts.Among them,the basicity of Mg promoter improves the basicity of the catalyst,but Mg is easy to lose in the reaction,resulting in a decrease in catalytic activity.When Fe is used as an additive,it can inhibit the excessive reduction of Cu⁺to Cu⁰,increase the value of Cu⁺/（Cu⁺+Cu⁰）,and thus improve the catalytic activity.2.CuO/AC catalysts were prepared by ammonia evaporation method with activated carbon as the carrier,basic copper carbonate or copper nitrate as the copper source,and calcined or strong alkali treatment.The effects of copper source and treatment methods on catalyst composition and ethynylation of formaldehyde performance were investigated.It was found that the catalysts were stable and better dispersed after strong alkali treatment with alkaline copper carbonate as the copper source.Subsequently,the effect of loading on the ethynylation of formaldehyde performance was investigated,and it was found that the catalyst activity increased with increasing loading,but when the loading is too high,the Cu species aggregated,the grain size increased,and the dispersion decreased leading to lower catalytic activity,the optimum Cu loading is 45%.3.CuO-Fe₃O₄/AC catalysts were prepared by co-precipitation method using activated carbon as carrier and Fe₃O₄ as magnetic center.The effect of p H value of precipitation environment on the performance of catalysts for the ethynylation of formaldehyde was investigated.It was found that the Mg species in the mixed solution could not be precipitated at p H=8,which affected the catalyst activity.As the p H value gradually increased to 10,the Mg species gradually precipitated,and the activity of the catalyst was improved due to the additive effect of Mg.When the precipitation p H continues to rise to 12,the grain size of CuO species in the catalyst becomes smaller,and the dispersion is improved,the interface between CuO and metal oxides increases,and the stability of the catalyst is improved.