均相催化剂催化氧气氧化生物质制备甲酸  

Catalytic Oxidation of Biomass to Formic Acid under O_(2)with Homogeneous Catalysts

作　　者：侯玉翠[1] 何卓森 任树行[2] 吴卫泽[2] Yucui Hou;Zhuosen He;Shuhang Ren;Weize Wu(College of Chemistry and Materials,Taiyuan Normal University,Jinzhong 030619,Shanxi Province,China;State Key Laboratory of Chemical Resource Engineering,College of Chemical Engineering,Beijing University of Chemical Technology,Beijing 100029,China)

机构地区：[1]太原师范学院化学与材料学院,山西晋中030619 [2]北京化工大学化学工程学院,化工资源有效利用国家重点实验室,北京100029

出　　处：《物理化学学报》2023年第9期53-68,共16页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(22178017,21706007);财政部教育部长效机制项目(BUCT)资助。

摘　　要：甲酸是一种重要的化工原料,以可再生生物质为原料,通过催化氧气氧化制备甲酸具有重要意义。对于不溶于水的生物质原料的转化,采用可溶于水的均相催化剂体系证明是有效的。本文总结了均相催化剂体系(包括含钒杂多酸、含钒杂多酸+H_(2)SO_(4)、含钒杂多酸基离子液体、NaVO_(3)+H_(2)SO_(4)、VOSO_(4)、NaVO_(3)-FeCl_(3)+H_(2)SO_(4)、FeCl_(3)+H_(2)SO_(4)等)在催化氧气氧化生物质(包括生物质模型化合物、纤维素、木材、秸秆和玉米芯等)制备甲酸方面的研究,分析了其转化的过程和机理。最后,指出了目前催化氧化生物质制备甲酸存在的问题和挑战。Formic acid(FA)is an important chemical for the production of leathers,medicines,preservatives,rubbers,textiles,and other materials.FA is also used as H_(2)and CO carriers,and as a fuel in fuel cells.Although most commonly synthesized from fossil fuels,FA can also be obtained from more sustainable sources,such as biomass(e.g.,straw,husk,and sawdust).Oxygen and air are affordable and easily available oxidants used for the oxidation of biomass to FA.Because solid biomass is not soluble in water or organic solvents,homogeneous catalysts are preferred for the catalytic oxidation of biomass to FA by O_(2)in water.It has been demonstrated that homogeneous catalysts,such as vanadium-containing heteropoly acids(HPA),HPA+H_(2)SO_(4),NaVO_(3)+H_(2)SO_(4),HPAcontaining ionic liquids,VOSO_(4),NaVO_(3)-FeCl_(3)+H_(2)SO_(4),and FeCl_(3)+H_(2)SO_(4),can convert complex biomass substrates to FA with high atom economy using O_(2)as the oxidant.The reported biomass substrates include model compounds,cellulose,wood,straw,and corncobs.The reaction conditions were summarized to compare the biomass conversions and FA yields.Vanadium-containing catalysts had the highest FA yield at mild conditions(T≤170ºC and P(O_(2))≤3 MPa).Both the reaction rate and FA yield were improved by adding H_(2)SO_(4).This high conversion can be explained by an electron transfer and oxygen transfer(ET-OT)mechanism,where high-valence transition metals(V^(5+)or Fe3+)oxidize biomass to FA and are reduced to low-valence species(V^(4+)or Fe^(2+)).The catalysts are then regenerated by O_(2).This reaction occurs through C2―C3 and/or C3―C4 bond cleavages via retro-aldol condensation,followed by continued C―C bond cleavages to form FA.Using isotope-labeled D-glucose as substrate,we determined that oxidation occurs via successive C1―C2 bond cleavages;a V^(5+)catalyst reacts with C1―C2 to form a five-membered ring complex,without C―H bond cleavages,followed by oxidation from another V^(5+)species to form FA.The oxidation of solid cellulose occurs throu

关 键 词：甲酸 生物质 氧气 催化氧化 均相催化剂 

分 类 号：O643[理学—物理化学]