Mg-Al hydrotalcites as solid base catalysts for alcoholysis of propylene oxide

In this study, Mg-Al-CO3 hydrotalcite (Mg-Al LDH) as a promising base catalyst was used for the synthesis of 1-methoxy-2-propanol (MP) from propylene oxide and methanol. Mg-Al LDHs were prepared by urea decomposition and coprecipitation methods. The effect of preparation method on the microstructure, the basic properties and the catalytic performance of Mg-Al LDHs was studied combining XRD, FTIR, TG-DTA, SEM and Hammett titration method. The results indicate that the urea method increased the crystallinity of Mg-Al LDH with well-developing hexagonal plate-shaped particles. Compared to the coprecipitation sample (T-LDH), the urea sample (U-LDH) possessed a higher crystallinity with larger specific surface area and aspect ratio, which also related with a higher catalytic activity. High crystallinity and large specific surface area were associated with more acid-base hydroxyl pairs (basic sites). The metal oxide obtained by calcining the U-LDH at 500 °C had the highest catalytic performance due to the highest basicity.