Daolai Sun

Production of C4 and C5 alcohols from biomass-derived materials

C4 and C5 diols and alcohols are important commodity chemicals mainly used as monomers in the production of polyesters, polyurethanes and polyethers. C4 and C5, on the other hand, can be used in the fuel industry for the preparation of additives to boost the gasoline octane number. The present critical review covers those reports describing the obtainment of these diols and alcohols from precursors derived from biomass. Emphasis is made on the description of the catalysts required for these transformations and on common traits referring to the bifunctionality combining hydrogenation activity and acidity and on the mechanistic proposals. The need for finding a suitable replacement for noble metals on the composition of these catalysts has been remarked throughout the review.

Glycerol as a potential renewable raw material for acrylic acid production

Production of fuels and chemicals from renewable biomass resources is an attractive way to alleviate the shortage of fossil fuels and reduce CO2 emission. Glycerol is an important biomass derivative currently produced as a by-product in the manufacture of biodiesel in a huge amount close to 10 wt% of the overall biodiesel production. The application of glycerol as a renewable raw material has attracted much attention in the last decade, and some catalytic technologies for the conversion of glycerol into useful chemicals such as methanol, epichlorohydrin, and 1,2-propanediol have been established. Acrylic acid is an important bulk chemical widely used in the manufacture of polymeric products and is currently produced in the petrochemical industry via two-step gas-phase oxidation of propylene. The depletion of fossil resources motivates developments in the production of acrylic acid from renewable raw materials. Glycerol has potential for use as a raw material for the production of acrylic acid, and the variety of glycerol derivatives provides opportunities for producing acrylic acid from glycerol through different ways. In this review, possible routes and the corresponding catalytic technologies for the conversion of glycerol to acrylic acid are primarily summarized, and the advantages as well as the challenges in each route are discussed.

Efficient formation of nitriles in the vapor-phase catalytic dehydration of aldoximes

A vapor-phase dehydration of acetaldoxime to acetonitrile was investigated over various solid catalysts. Among the tested catalysts, ZrO2, Al2O3 and SiO2 showed high catalytic activity for the formation of acetonitrile from acetaldoxime, while the correlation between catalytic activity and the acid property of the catalysts was not observed. Weak acidic sites such as silanols sufficiently work as catalytic sites for the dehydration, which does not require strong acids such as zeolites. Several SiO2 catalysts with different physical properties were tested, and the SiO2 with the smallest pore size and the highest specific surface area showed the highest catalytic activity for the formation of acetonitrile. Because the dehydration of acetaldoxime to acetonitrile is exothermic, a large amount of reaction heat was generated during the reaction, and the reaction temperature was found to be significantly affected by the feed rate of the reactant and the flow rate of the carrier gas. In order to effectively utilize the in situ generated reaction heat, the dehydration of acetaldoxime to acetonitrile without using the external heat supply was conducted. The temperature was controllable even in the absence of the external heat, and the acetonitrile yield higher than 90% could be achieved in such a green operation under the environment-friendly adiabatic conditions.