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<p>The valorization of glycerol, a major by-product of biodiesel production, into high-value chemicals is of growing interest. In this study, Li/Mg composite catalysts were synthesized via a co–precipitation method and systematically optimized for the transesterification of glycerol with dimethyl carbonate (DMC) to produce glycerol carbonate (GC). Structural characterization by XRD, FT–IR, and CO<sub>2</sub>-TPD revealed that calcination at 500&#xa0;°C transforms Mg(OH)<sub>2</sub> into MgO, decomposes NaNO<sub>3</sub> into highly dispersed Na–O species, and stabilizes Li<sub>2</sub>CO<sub>3</sub>, generating a balanced distribution of medium–strong and strong basic sites. The catalytic performance was strongly dependent on Li/Mg molar ratio, calcination temperature and time, as well as the reaction parameters. Under optimized conditions—n(Li): n(Mg) = 4:1, calcination at 500&#xa0;°C for 4&#xa0;h, n(DMC): n(glycerol) = 3:1, reaction temperature 80&#xa0;°C, reaction time 2&#xa0;h, and 3 wt% catalyst loading, the modified catalyst achieved 97.57% of glycerol conversion and 97.86% of GC yield, and 95.48% of GC selectivity. The catalyst exhibited excellent reusability, maintaining performance over four consecutive cycles. Mechanistic analysis indicates that the medium–strong and strong basic sites activate glycerol hydroxyl groups to promote transesterification, while excessive strong basicity accelerates GC decomposition. This work demonstrates that controlled lithium incorporation and optimized calcination conditions effectively tune surface basicity, resulting in a robust and recyclable catalyst for efficient GC production, providing insights for the design of base catalysts for biomass–derived platform chemicals.</p>

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Calcination-induced structural modulation of Li/Mg catalysts for efficient glycerol carbonate synthesis

  • 期刊论文

  • 发表日期：

    2026年6月22日

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  • Liu Zhenmin,
  • Li Bin,
  • Wang Jiaqi,
  • Wang Xiaoxiao,
  • Lu Haiqiang

摘要

The valorization of glycerol, a major by-product of biodiesel production, into high-value chemicals is of growing interest. In this study, Li/Mg composite catalysts were synthesized via a co–precipitation method and systematically optimized for the transesterification of glycerol with dimethyl carbonate (DMC) to produce glycerol carbonate (GC). Structural characterization by XRD, FT–IR, and CO2-TPD revealed that calcination at 500 °C transforms Mg(OH)2 into MgO, decomposes NaNO3 into highly dispersed Na–O species, and stabilizes Li2CO3, generating a balanced distribution of medium–strong and strong basic sites. The catalytic performance was strongly dependent on Li/Mg molar ratio, calcination temperature and time, as well as the reaction parameters. Under optimized conditions—n(Li): n(Mg) = 4:1, calcination at 500 °C for 4 h, n(DMC): n(glycerol) = 3:1, reaction temperature 80 °C, reaction time 2 h, and 3 wt% catalyst loading, the modified catalyst achieved 97.57% of glycerol conversion and 97.86% of GC yield, and 95.48% of GC selectivity. The catalyst exhibited excellent reusability, maintaining performance over four consecutive cycles. Mechanistic analysis indicates that the medium–strong and strong basic sites activate glycerol hydroxyl groups to promote transesterification, while excessive strong basicity accelerates GC decomposition. This work demonstrates that controlled lithium incorporation and optimized calcination conditions effectively tune surface basicity, resulting in a robust and recyclable catalyst for efficient GC production, providing insights for the design of base catalysts for biomass–derived platform chemicals.