Because of its high purity and excellent orientation, mesophase pitch is a superior precursor for high-performance car-bon materials. However, the preparation of top-notch mesophase pitch faces challenges. Catalytic p...Because of its high purity and excellent orientation, mesophase pitch is a superior precursor for high-performance car-bon materials. However, the preparation of top-notch mesophase pitch faces challenges. Catalytic polycondensation at low temperat-ures is more favorable for synthesizing mesophase pitch, because it circumvents the high-temperature free radical reaction of other thermal polycondensation approaches. The reaction is gentle and can be easily controlled. It has the potential to significantly im-prove the yield of mesophase pitch and easily introduce naphthenic characteristics into the molecules, catalytic polycondensation is therefore a preferred method of synthesizing highly spinnable mesophase pitch. This review provides a synopsis of the selective pre-treatment of the raw materials to prepare different mesophase pitches, and explains the reaction mechanism and associated research advances for different catalytic systems in recent years. Finally, how to manufacture high-quality mesophase pitch by using a cata-lyst-promoter system is summarized and proposed, which may provide a theoretical basis for the future design of high-quality pitch molecules.展开更多
An inexpensive Fe doped aluminoborate consisted of 18% Fe in PKU-1 material that exhibits high selectivity of 4-hydroxymethy-2,2-dimethyl^(-1),3-dioxolane (Solketal, 98.3%), considerable activity (TOF 51.7 h-1), and r...An inexpensive Fe doped aluminoborate consisted of 18% Fe in PKU-1 material that exhibits high selectivity of 4-hydroxymethy-2,2-dimethyl^(-1),3-dioxolane (Solketal, 98.3%), considerable activity (TOF 51.7 h-1), and recyclable ability in the ketalization of glycerol to Solketal with acetone at 318 K has been developed. Our study demonstrated that the structure of Fe (less agglomerated iron species vs. FeO clusters) can be tuned by changing Fe loading in the PKU-1 material, which correlated well with experimental observations. Furthermore, the surface boron sites were promoted by iron loading and behaved as Lewis-acid sites to facilitate the reaction process of glycerol ketalization, while the Solketal selectivity was closely related with the structure of iron species in PKU-1, which was proved by kinetic studies, density function theory (DFT) calculations, and a series of spectroscopy studies. This investigation demonstrates that the surface B sites can play important roles in the reaction instead of being spectators.展开更多
A series of {2Fe3S} complexes bearing phosphino thioether chelating ligand were synthesized on the basis of Fe2（Me2pdt）（1,2-Cy2PC6H4SMe）（CO）4 （Me2pdt= Me2C（CH2S ）2, 1）. The disubstituted Fe（1）Fe（1） compo...A series of {2Fe3S} complexes bearing phosphino thioether chelating ligand were synthesized on the basis of Fe2（Me2pdt）（1,2-Cy2PC6H4SMe）（CO）4 （Me2pdt= Me2C（CH2S ）2, 1）. The disubstituted Fe（1）Fe（1） compound 1 exhibits a reversible one-electron redox even for [Fe（Ⅰ）Fe（Ⅱ）]＋/0 couple. Based on the oxidation of I to [1]＋, the tri-substituted [Fe（Ⅰ）Fe（Ⅱ）]＋ cationic complex [Fe2/Me2pdt）/1,2-Cy2PC6H4SMe） （PPh3）（CO）3]＋ （[2]＋） was synthesized. Reduction of [2]＋ provided the neutral tri-substituted Fe（l）Fe（1） compound 2. The substitution of the CO in I ligand by PPh3 results in an anodic shift of the Fe11Fe＋/Fe1Fe1 couple of470 mV. Most importantly, this substitution also leads to the Fe-Fe bonds in 1 and 2 with large Lewis basicity difference, i.e. △pKaMeCN ～ 10.展开更多
文摘Because of its high purity and excellent orientation, mesophase pitch is a superior precursor for high-performance car-bon materials. However, the preparation of top-notch mesophase pitch faces challenges. Catalytic polycondensation at low temperat-ures is more favorable for synthesizing mesophase pitch, because it circumvents the high-temperature free radical reaction of other thermal polycondensation approaches. The reaction is gentle and can be easily controlled. It has the potential to significantly im-prove the yield of mesophase pitch and easily introduce naphthenic characteristics into the molecules, catalytic polycondensation is therefore a preferred method of synthesizing highly spinnable mesophase pitch. This review provides a synopsis of the selective pre-treatment of the raw materials to prepare different mesophase pitches, and explains the reaction mechanism and associated research advances for different catalytic systems in recent years. Finally, how to manufacture high-quality mesophase pitch by using a cata-lyst-promoter system is summarized and proposed, which may provide a theoretical basis for the future design of high-quality pitch molecules.
基金financially supported by the Scientific and Technological Research Program of Chongqing Municipal Education Commission (Nos. KJQN202000823 and KJZD-K201900802)Research project of Chongqing Technology and Business University(No. 1956058)+2 种基金Scientific Platform ProjectMinistry of Education (No. fykf201905)US Department of Energy Office of Basic Energy Sciences,Division of Chemical,Biological and Geological Sciences (No. DE-FG02-86ER13622.A000) for support of this research。
文摘An inexpensive Fe doped aluminoborate consisted of 18% Fe in PKU-1 material that exhibits high selectivity of 4-hydroxymethy-2,2-dimethyl^(-1),3-dioxolane (Solketal, 98.3%), considerable activity (TOF 51.7 h-1), and recyclable ability in the ketalization of glycerol to Solketal with acetone at 318 K has been developed. Our study demonstrated that the structure of Fe (less agglomerated iron species vs. FeO clusters) can be tuned by changing Fe loading in the PKU-1 material, which correlated well with experimental observations. Furthermore, the surface boron sites were promoted by iron loading and behaved as Lewis-acid sites to facilitate the reaction process of glycerol ketalization, while the Solketal selectivity was closely related with the structure of iron species in PKU-1, which was proved by kinetic studies, density function theory (DFT) calculations, and a series of spectroscopy studies. This investigation demonstrates that the surface B sites can play important roles in the reaction instead of being spectators.
基金financial support from the "1000 Youth Talents Plan" the Natural Science Foundation of China (Nos. 21402107, 91427303)IIT Kanpur for funding
文摘A series of {2Fe3S} complexes bearing phosphino thioether chelating ligand were synthesized on the basis of Fe2（Me2pdt）（1,2-Cy2PC6H4SMe）（CO）4 （Me2pdt= Me2C（CH2S ）2, 1）. The disubstituted Fe（1）Fe（1） compound 1 exhibits a reversible one-electron redox even for [Fe（Ⅰ）Fe（Ⅱ）]＋/0 couple. Based on the oxidation of I to [1]＋, the tri-substituted [Fe（Ⅰ）Fe（Ⅱ）]＋ cationic complex [Fe2/Me2pdt）/1,2-Cy2PC6H4SMe） （PPh3）（CO）3]＋ （[2]＋） was synthesized. Reduction of [2]＋ provided the neutral tri-substituted Fe（l）Fe（1） compound 2. The substitution of the CO in I ligand by PPh3 results in an anodic shift of the Fe11Fe＋/Fe1Fe1 couple of470 mV. Most importantly, this substitution also leads to the Fe-Fe bonds in 1 and 2 with large Lewis basicity difference, i.e. △pKaMeCN ～ 10.
