Excess soluble alkalis to prepare highly efficient MgO with relative low surface oxygen content applied in DMC synthesis

The activities of various MgO catalysts, which were prepared from different methods such as hydration synthesis, thermal decomposition, combustion, sol–gel and co-precipitation, were conducted in dimethyl carbonate (DMC) synthesis via transesterification of ethylene carbonate with methanol. MgO-P-Na₂CO₃-3.14 synthesized by the excess Na₂CO₃ precipitation compared the best catalytic activity and stability, which could be reused for seven times without obvious deactivation. The DMC yield was as high as 69.97% at 68 °C. The transesterification reaction could be separated into two steps, and the samples obtained by NaOH precipitant exhibited better ring-opening capability, while the catalysts acquired by Na₂CO₃ precipitant displayed superior transesterification ability. The structure-performance relationship was evaluated by multiple characterization methods. The results indicated that the as-synthesized catalyst derived from dried precursors with more crystalline magnesium carbonate was favorable for the promotion of DMC yield, and MgO-P-Na₂CO₃-3.14 with more Mg-O pairs, which were the active center for the transesterification of 2-hydroxyethyl methyl carbonate (HEMC) intermediate with methanol, resulted in more moderately basic sites left that was in accordance with the DMC yield variation. MgO-P-Na₂CO₃-3.14 with greater BET surface area and mesopore volume, relative low surface oxygen content and larger moderately basic sites amount compared the excellent activity in DMC synthesis.

Recent Development of Heterogeneous Catalysis in the Transesterification of Glycerol to Glycerol Carbonate

Glycerol is one of the most crucial by-products in the production of biodiesel, and owing to its oversaturation in the market, several synthetic strategies have been developed to transform it into other higher value-added products such as glycerol carbonate, epichlorohydrin, 1,3-propanediol, etc. Amongst them, glycerol carbonate is considered to be the most valuable product. Considering the facile separation and reusability of catalyst, heterogeneous base catalysts have attracted considerable attention due to the obvious advantages over Brϕnsted acid and homogeneous base catalysts in the transesterification of glycerol. Herein, we will give a short overview on the recent development of the heterogeneous catalysis in the transesterification of glycerol with dialkyl carbonate. Focus will be concentrated on the heterogeneous base catalysts including alkaline-earth metal oxides (MgO, CaO, and mixed oxides), hydrotalcites, zeolites, clinoptilolites, organic bases, etc. Their catalytic mechanisms during the heterogeneous process will be elucidated in detail.

Microscale flower-like magnesium oxide for highly efficient photocatalytic degradation of organic dyes in aqueous solution

Flower-like MgO microparticles with excellent photocatalytic performance in degradation of various organic dyes were synthesized by a facile precipitation method via the reaction between Mg²⁺ and CO₃²⁻ at 70 °C.

Development of a trapezoidal MgO catalyst for highly-efficient transesterification of glycerol and dimethyl carbonate

Trapezoidal MgO has been developed for the transesterification of glycerol and dimethyl carbonate with a glycerol carbonate yield of more than 99%.

Hierarchically structured magnesium based oxides: synthesis strategies and applications in organic pollutant remediation

In this highlight, we review the design and formation of MgO based hierarchical structures and cover some selected examples on their applications in adsorption of organic contaminants.

Large-scale synthesis of uniformly dispersed hexagram-like gibbsite by a controlled replacement reaction

A facile, convenient and mild method has been developed for synthesis of uniformly dispersed 2D six-pointed star-like gibbsite micro-nano crystals with lateral size around 2.5 μm and thickness around 100 nm.