Gas-Phase Hydrogenolysis Of Dimethyl Oxalate To Methyl Glycolate:Galvanic Reaction Preparation Of Ag-CuO_x/Ni-Foam Catalysts And Their Catalytic Performance

Methyl glycolate(MG)is an essential fine chemical material,which could be applied for further synthesis into polyglycolic acid,pharmaceutical products,perfumes and other fine chemicals.Not only it's a good solvent for robber,cellulose and resin,but also it could be alcoholized into different kinds of esters.Hydrogenation and hydrolysis of MG could get glycol,alcohol,and glycolic acid,which could be applied in anti-freeze and detergent,respectively.Nowadays,a whole family of MG down-steam products has taken off in our national chemical,pharmaceutical,and energy industries.Traditional MG synthesis processes were mainly by coupling of glycol and formaldehyde,formaldehyde carbonization and esterification method,and coupling of formaldehyde and methyl formate,but deficits like environmental pollution,extremely pressure ambience,and low stability of catalyst could not be avoided.Hence,gas-phase hydrogenation of dimethyl oxalate(DMO)into MG has been studied because of its green process and high atom-economy.But selectivity of MG was too low,MG was easily deep hydrogenated into ethylene glycol(EG),active sites sintering result from hotspots due to low heat-transfer coefficient of the catalyst,silica of the catalyst supporters drained away as the reaction operates with methanol as the solvent,all those factors hindered its further application.This study successfully engineered a high-performance 0.4-Ag-28-CuOx/Ni-foam catalyst for hydrogenation of DMO to MG via sequential galvanic deposition of Ag and Cu onto a Ni-foam.It provided a unique combination of SiO2-free property,enhanced heat/mass transfer and longtime stability for the hydrogenation of DMO into MGWe found that silver was responsible to apportion the proportion of Cu+ and Cu0 to an appropriate scale of optimal potency for DMO-to-MG.Volcano-shaped DMO conversion and MG selectivity were observed against the ratio of Cu+ to(Cu0+Cu+).That was mounted up with the increase in Ag content.This observation proved Ag additives provided the ability for tuning the catalyst activity and selectivity.