Xun Hu

Hydrogenation of fourteen biomass-derived phenolics in water and in methanol: their distinct reaction behaviours

Phenolic compounds are an important component of pyrolysis oil (bio-oil). Understanding their reaction behaviours during hydrogenation helps to clarify the reaction network during hydrotreatment of bio-oil. This study investigated the hydrogenation of typical phenolic compounds in bio-oil in water, which is an important fraction of bio-oil, and in methanol, which is used to esterify bio-oil. The results indicated that hydrogenation of the phenolics is more efficient in water than in methanol. With water medium, both the unsaturated oxygen-containing functionalities and the benzene ring of the phenolics can be effectively hydrogenated. In comparison, with methanol medium, only the unsaturated oxygen-containing functionality can be hydrogenated, while the hydrogenation of the benzene ring is rather difficult. Stereoselectivity was also observed in the hydrogenation of phenolics with three or more hydroxyl groups/methoxyl groups. For phenolics with two hydroxyl groups/methoxyl groups, the hydrogenation produces both cis- and trans-configurations.

High-Efficiency Inhibition of Gravity Segregation in Al–Bi Immiscible Alloys by Adding Lanthanum

The inhibition of gravity segregation has been a long-standing challenge in fabrication and applications of homogeneous immiscible alloys. Therefore, the effect of rare-earth La on the gravity segregation of Al–Bi immiscible alloys was investigated to understand the homogenization mechanism. The results showed that the addition of La can completely suppress the gravity segregation. This is attributed to the nucleation of Bi-rich liquid phase on the in-situ produced LaBi2 phase and the change of the shape of LaBi2@Bi droplets. In addition, a novel strategy is developed to prepare the homogeneous immiscible alloys through the addition of rare-earth elements. This strategy not only is applicable to other immiscible alloys, but also is conducive to finding more elements to suppress the gravity segregation. This study provided a useful reference for the fabrication of the homogeneous immiscible alloys.