La2O2CO3-Cu-Al mixed oxide for efficient dimethyl carbonate production via transesterification: Kinetic analysis and a novel hybrid PSO-BP modeling
La 2 O 2 CO 3 -Cu-Al mixed oxides (CL X A-LDO) were fabricated via the calcination of lanthanum carbonate-doped Cu-Al layered double hydroxides (LDHs) with unique wool-scale-like lamellar structures. CL X A-LDO were employed for the synthesis of dimethyl carbonate (DMC) via the transesterification of methanol with propylene carbonate (PC). Characterization via XRD, FT-IR, TG, and SEM confirmed that lanthanum carbonate-doped Cu-Al LDHs with unique wool-scale-like lamellar structures were successfully prepared. After calcination, these precursors transformed into La 2 O 2 CO 3 -CuO-Al 2 O 3 composites. CO 2 -TPD and XPS results indicate that CL 1.0 A-LDO-600 possesses abundant medium/strong basic sites and a favorable O II /O I ratio. Consequently, CL 1.0 A-LDO-600 exhibited a PC conversion of 68.44% and a DMC yield of 67.84% under mild conditions (80 °C, 2 h, catalyst loading 2.0 wt%, methanol/PC molar ratio = 10). Moreover, CL 1.0 A-LDO-600 demonstrated high stability, with only a modest activity loss (Δ PC = 6.2%) after six consecutive cycles. The kinetic analysis indicated a complex reaction mechanism. However, this behavior was effectively simplified to a pseudo-first-order reaction model, providing activation energies of Ea(k + ) = 47.17 kJ·mol -1 (forward) and Ea(k - ) = 44.46 kJ·mol -1 (reverse). The experimental data were systematically validated using a particle swarm optimization-backpropagation artificial neural network (PSO-BP) model. The hybrid model demonstrated superior predictive accuracy, achieving R 2 values of 0.9956 and 0.9916 for the training and testing sets, respectively, thereby outperforming the conventional BP model. This work provides fundamental insights into the rational design of LDHs-derived mixed oxide catalysts for sustainable DMC synthesis.
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