超临界二氧化碳合成绿色化学品碳酸二甲酯的研究的综述报告

超临界二氧化碳合成绿色化学品碳酸二甲酯的研究的综述报告Abstract:Carbondioxide(CO2)isagreenhousegasthatcontributestoclimatechange.Asaresult,researcheffortshavebeenfocusedondevelopingwaystoreduceCO2emissionsandmitigatetheirimpactontheenvironment.OnepotentialsolutionistheuseofCO2asarawmaterialforthesynthesisofvaluablechemicals.Carbondioxideisconsideredasasustainablesourceofcarbonduetoitsabundance,lowcost,andlowtoxicity.SupercriticalCO2hasbeenutilizedfortheproductionofgreenchemicals,andonesuchchemicalisdimethylcarbonate(DMC).DMCisanon-toxic,biodegradable,andenvironmentallyfriendlycompoundthathasvariousapplicationsinthechemicalindustry.ThisreviewarticleprovidesanoverviewoftheuseofsupercriticalCO2forthesynthesisofDMCfromCO2.Introduction:Dimethylcarbonate(DMC),(CH3O)2CO,isanorganiccompoundthatiswidelyusedasasolvent,afueladditive,areagent,andastartingmaterialforthesynthesisofotherchemicals.DMChasmanyadvantagesoverotherorganicsolvents,suchashighboilingpoint,lowtoxicity,excellentbiodegradability,andgoodsolventpowerforpolarandnonpolarsubstances.DMCisconsideredasagreenchemicalduetoitslowenvironmentalimpactandhighefficiencyinvariousapplications.ThetraditionalmethodforthesynthesisofDMCinvolvesthereactionofmethanolwithphosgene.Thismethodisnotenvironmentallyfriendlyandproducestoxicwaste.ThedevelopmentofagreenprocessforthesynthesisofDMCis,therefore,ofgreatimportance.OnepotentialsolutionistousecarbondioxideasarawmaterialforthesynthesisofDMC.CO2isanabundant,non-toxic,andlow-costsourceofcarbonthatcanbeusedtoreplaceconventionalfossilfuelsinvariouschemicalprocesses.SupercriticalCO2SupercriticalCO2(SC-CO2)isauniquesolventthathasbeenextensivelystudiedforchemicalapplications.SC-CO2isproducedwhenCO2isheatedandcompressedtoacriticaltemperatureandpressurewhereitattainsboththeliquidandgasphaseproperties.SC-CO2hasseveraladvantagesovertraditionalsolvents,includinghighdiffusivity,lowviscosity,lowsurfacetension,andtunablepolarity.Moreover,SC-CO2isenvironmentallybenign,non-toxic,andeasilyrecoveredandrecycled.SynthesisofDMCusingCO2ThesynthesisofDMCfromCO2involvestwomainsteps:thereactionofCO2withmethanoltoformmethylcarbonate(MC)andthesubsequenttransesterificationofMCwithmethanoltoproduceDMC.ThereactionofCO2withmethanolcanbecatalyzedbyvariousmetaloxides,includingZnO,MgO,CaO,andothers.Thereactionistypicallycarriedoutathighpressures(50-150bar)andtemperatures(150-250°C)inthepresenceofasolvent,suchastolueneordimethylsulfoxide(DMSO),toimprovethesolubilityofthereactants.ThetransesterificationofMCwithmethanolcanbecatalyzedbyvarioushomogeneousorheterogeneouscatalysts,suchassodiummethoxide,potassiumhydroxide,orcalciummagnesiumoxide(Ca-MgO).Thereactionistypicallycarriedoutatatmosphericpressureandtemperaturesrangingfrom70-100°C.RecentadvancesinthesynthesisofDMCusingCO2havefocusedonimprovingthereactionefficiency,increasingtheyieldandselectivity,andminimizingtheuseofhazardoussolventsandcatalysts.Forexample,heterogeneouscatalystssuchaszeolites,metal-organicframeworks(MOFs),andmesoporousmaterialshavebeenutilizedforthereactionofCO2withmethanol.Thesecatalystsexhibithighactivity,selectivity,andstabilityandcanbeeasilyseparatedfromthereactionmixture.AnotherpromisingapproachistheuseofphotochemicalorelectrochemicalmethodstoactivateCO2andpromoteitsreactionwithmethanol.Thesemethodshavetheadvantageofusingrenewableenergysourcesanddonotrequirehighpressuresortemperatures.Conclusion:TheuseofsupercriticalCO2forthesynthesisofDMCfromCO2isapromisingapproachforproducinggreenchemicals.TheutilizationofCO2asarawmaterialinsteadofconventionalfossilfuelscanreduceCO2emissionsandmitigatetheimpactofclimatechange.SC-CO2isanexcellentsolventforthereactionofCO2withmethanolduetoitsuniquesolventpropertiesandenvironmentalbenefits.Furthermore,theuseofheterogeneouscatalystsandphotochemicalorelectrochemicalmethodscanenhancethereactionefficiencyandreducetheuseofhazardoussolventsand