Fangming Jin

Highly efficient and autocatalytic H 2 O dissociation for CO 2 reduction into formic acid with zinc

Artificial photosynthesis, specifically H2O dissociation for CO2 reduction with solar energy, is regarded as one of the most promising methods for sustainable energy and utilisation of environmental resources. However, a highly efficient conversion still remains extremely challenging. The hydrogenation of CO2 is regarded as the most commercially feasible method, but this method requires either exotic catalysts or high-purity hydrogen and hydrogen storage, which are regarded as an energy-intensive process. Here we report a highly efficient method of H2O dissociation for reducing CO2 into chemicals with Zn powder that produces formic acid with a high yield of approximately 80%, and this reaction is revealed for the first time as an autocatalytic process in which an active intermediate, ZnH− complex, serves as the active hydrogen. The proposed process can assist in developing a new concept for improving artificial photosynthetic efficiency by coupling geochemistry, specifically the metal-based reduction of H2O and CO2, with solar-driven thermochemistry for reducing metal oxide into metal.

Production of 2,5-hexanedione and 3-methyl-2-cyclopenten-1-one from 5-hydroxymethylfurfural

A novel approach for the production of 2,5-hexanedione (HDN) and 3-methyl-2-cyclopenten-1-one (3-MCO) from 5-hydroxymethylfurfural (HMF) by water splitting with Zn is reported for the first time. The use of high temperature water (HTW) conditions is the key for the efficient conversion of HMF to HDN and 3-MCO. Parameters regarding the Zn amount, temperature and reaction time are optimized and HDN and 3-MCO are produced in 27.3% and 30.5% yields, respectively. The roles of HTW and ZnO obtained by oxidation of Zn in water for the conversion of HMF, together with intermediate structures, are discussed to understand the mechanism of the reaction.

Selective hydrogenation of levulinate esters to 1,4-pentanediol using a ternary skeletal CuAlZn catalyst

A non-noble ternary skeletal CuAlZn catalyst was designed for direct hydrogenation of ethyl levulinate (EL) to 1,4-pentanediol (1,4-PDO). 98% yield of 1,4-PDO, which is the highest yield achieved by heterogeneous catalysts so far, was obtained over CuAlZn-3.5 h. Zn in the skeletal alloy was found as a vital promoter for adjusting the selectivity of 1,4-PDO production.

Water Under High Temperature and Pressure Conditions and Its Applications to Develop Green Technologies for Biomass Conversion

This chapter introduces the chemical and physical properties of water under high temperature and pressure, such as ion product, density, dielectric constant and hydrogen bonding, and the applications of these properties on biomass conversion. These properties that are adjustable by changing the reaction temperature and pressure or adding additives are central to the reactivity of the biomass feedstock to break the C–C or C–O bonds. For example, glucose will follow different reaction pathways under acidic or alkali environment which is related to the ion product of water. Presently, hundreds of strategies utilizing these properties to transform biomass into target products intentionally or unintentionally are proposed. In this chapter, the hydrothermal processes applied in the conversion of biomass including cellulose, hemicelluloses, lignin and glycerin into commodity chemicals such as organic acids are mainly reviewed. In addition, the production of CO2 as a byproduct from biomass conversion is sometimes inevitable. To achieve 100 % carbon yield, the process of reduction of CO2 is often neglected but required. In the last section, the one pot reaction of glycerin conversion and CO2 reduction is reviewed based on the hydrogen bonding property.

Improved two-step hydrothermal process for acetic acid production from carbohydrate biomass

An improved two-step process for converting carbohydrate biomass to acetic acid under hydrothermal conditions is proposed. The first step consists of the production of lactic acid from carbohydrate biomass, and the second step consists of conversion of the lactic acid obtained in the first step to acetic acid using CuO as an oxidant. The results indicated that CuO as an oxidant in the second step can significantly improve the production of high-purity acetic acid from lactic acid, and the maximum yield of acetic acid was 61%, with a purity of 90%. The yield of acetic acid obtained using the improved two-step hydrothermal process from carbohydrate biomass, such as glucose, cellulose and starch, was greater than that obtained using traditional two-step process with H2O2 or O2. In addition, a proposed pathway for the production of acetic acid from lactic acid in the second step with CuO was also discussed. The present study provides a useful two-step process for the production of acetic acid from carbohydrate biomass.

A novel Pd/C-catalyzed conversion of glucose to 1,2-propanediol by water splitting with Zn

A novel Pd/C-catalysed conversion of glucose to 1,2-propanediol by water splitting with Zn was proposed. The yield of 1,2-akanediols reached 48%, mainly including 1,2-propanediol (33.3%), the reported highest yield from glucose. Water, as a solvent, provides an in situ and active hydrogen source. The formed ZnO acts as a catalyst with Pd/C.

Chemoselective synthesis of propionic acid from biomass and lactic acid over a cobalt catalyst in aqueous media

A new non-fermentative process for the transformation of biomass carbohydrates and lactic acid (LA) into propionic acid (PA) was first reported over a cobalt catalyst in water. The Co catalyst exhibited high catalytic activity for the formation of PA with Zn as a reductant. Various parameters, such as catalyst loading, Zn weight, water volume, temperature and reaction time, were investigated to improve the yield of PA, and the maximum value of 58.8% was achieved in the presence of 4 mmol Co and 10 mmol Zn in 7.5 mL H2O at 250 °C for 2 h. The recyclability of the Co catalyst showed that Co could be effectively repeated four times without the loss of activity. Moreover, the result showed that in situ-formed ZnO by oxidation of Zn in water could efficiently enhance the catalytic activity of the Co catalyst in the conversion of LA. Besides, direct conversion of carbohydrate biomass, such as glucose, cellulose and starch, or a similar compound such as glycolic acid also afforded the desired products. The present study provides great significance for practical application on the production of PA from LA and biomass carbohydrates.

Efficient conversion of biomass-derived furfuryl alcohol to levulinate esters over commercial α-Fe2O3

An efficient process for the production of levulinate esters from biomass-derived furfuryl alcohol in liquid alcohol over commercial α-Fe2O3 was firstly investigated. Among the catalysts we tested, α-Fe2O3, a cheap, commercially available and environmentally benign catalyst, exhibited a remarkable catalytic performance for the transformation and gives levulinate esters in good yield compared to the previous studies. The corresponding esters such as methyl levulinate, ethyl levulinate and butyl levulinate were obtained in high yields under optimized reaction conditions. Several influence factors for the formation of levulinate esters were also discussed. A plausible reaction mechanism for the formation of levulinate ester from furfuryl alcohol was proposed. From the viewpoint of practice and economy, the present study provides a potential application for the efficient synthesis of fine chemicals from biomass-derived compounds over cheap, commercially available and environmentally benign catalysts.

A novel approach to reduction of CO2 into methanol by water splitting with aluminum over a copper catalyst

A novel method of water splitting for CO2 reduction into methanol was proposed by directly using commercially available and non-precious Al and Cu powder as a reductant and catalyst, respectively. A 22% yield of methanol was obtained from CO2. This technique is simple and environmentally friendly, and also provides an example of a multitude of possible chemical reactions for CO2 conversion.

Hydrothermal Conversion of Cellulose into Organic Acids with a CuO Oxidant

In this chapter, we review some recent progress on the acid/base-catalyzed hydrothermal conversion and oxidation of cellulose into organic acids mainly in our research group. A novel one-pot production of organic acids and metal copper from cellulose and CuO under alkaline hydrothermal conditions is introduced based on our former research. The mechanism of formation of organic acids and metal copper is discussed. A principal reaction pathway from cellulose to organic acids and their reactions are also discussed. The results show that from cellulose to organic acids, the production processes are mainly composed of four stages of reactions. The reaction conditions were also optimized for production of organic acids and copper. These results show that a selective production of organic acids including lactic acid, glycolic acid, acetic acid, and formic acid can be achieved by varying reaction temperature and time and ratio of CuO and NaOH addition.