Chemical synthesis of lactic acid from cellulose catalysed by lead(II) ions in water

该工作是博士生王炎良（实验）和王斌举（理论）以及邓卫平博士紧密合作的成果。The direct transformation of cellulose, which is the main component of lignocellulosic biomass, into building-block chemicals is the key to establishing biomass-based sustainable chemical processes. Only limited successes have been achieved for such transformations under mild conditions. Here we report the simple and efficient chemocatalytic conversion of cellulose in water in the presence of dilute lead(II) ions, into lactic acid, which is a high-value chemical used for the production of fine chemicals and biodegradable plastics. The lactic acid yield from microcrystalline cellulose and several lignocellulose-based raw biomasses is >60% at 463 K. Both theoretical and experimental studies suggest that lead(II) in combination with water catalyses a series of cascading steps for lactic acid formation, including the isomerization of glucose formed via the hydrolysis of cellulose into fructose, the selective cleavage of the C3–C4 bond of fructose to trioses and the selective conversion of trioses into lactic acid.该项研究工作得到国家自然科学基金委、科技部和教育部创新研究团队项目的资助

Stability and Elasticity of Quasi Hexagonal Fullerene Monolayer from First Principles Study

As a newly synthesized two dimensional carbon material, the stability study of monolayer fullerene networks or quasi hexagonal phase fullerenes (qhp C 60) is timely desirable. We have investigated the stabilities of qhp C 60, including thermal, structural, mechanical, and thermodynamic stabilities, as well as the bonding characteristics, ductility, and mechanical properties, via first principles calculations. The results show that qhp C 60 is energetically, mechanically, and thermodynamically stable. The thermodynamic stability of qhp C 60 at 300 K and 600 K is verified. The bonding characteristics of qhp C 60 are analyzed from the bond length, and it has sp(2) and sp(3) hybridization. The Pugh ratio (B/G) and Poisson's ratio (v) indicate similar ductility with graphite and graphene. We also found that qhp C 60 has the lowest hardness and the anisotropy of the material. In addition, the electronic characteristics, including electron localization function (ELF), crystal orbital Hamiltonian population (COHP), and density of states (DOS) at different temperatures, are analyzed to verify the thermal stability of the material. Our results might be helpful in the material design of qhp C 60 related applications