Alkaloid purification using rosin-based polymer-bonded silica stationary phase in HPLC.

Alkaloids are important natural products that exhibit a wide spectrum of pharmacological activities. To efficiently separate and purify them, a rosin-based polymer-bonded silica stationary phase in high-performance liquid chromatography was synthesized via the surface radical polymerization of ethylene glycol maleic rosinate acrylate and methacrylic acid onto functionalized silica. The stationary phases, columns, optimization of chromatographic conditions for alkaloids, and thermodynamic behavior of the analytes on the column were fully studied. Under the optimized conditions, the prepared column efficiently purified natural camptothecine, caffeine, and evodiamine with the corresponding purities of 92, 96, and 97%. With this work, we have developed an efficient approach to isolate alkaloids and promoted the research on rosin-based materials in biomedicine and analytical chemistry.

Dispersing Metallic Platinum on Green Rust Enables Effective and Selective Hydrogenation of Carbonyl Group in Cinnamaldehyde.

Layered double hydroxides (LDHs), a category of two-dimensional nanostructured layered materials, can be employed widely as supports, catalyst precursors, and actual catalysts in a variety of heterogeneous catalytic reactions. In this work, we reported a series of Fe-containing LDHs-supported Pt-based catalysts for base-free selective hydrogenation of cinnamaldehyde into cinnamyl alcohol. It was revealed that their catalytic performances were closely correlated to the compositions of LDH supports. Especially, highly selective hydrogenation of cinnamaldehyde could be achieved over the Fe(II)-Fe(III)-LDH (green rust, FeFe-LDH) supported Pt catalyst, with a high cinnamyl alcohol selectivity of about 92% at a conversion of 90% after a reaction of 2 h, superior to other Fe(III)-containing LDHs (e.g., NiFe-LDH, CoFe-LDH, and ZnFe-LDH) supported Pt ones. It was demonstrated that the high catalytic efficiency of Pt/FeFe-LDH mainly originated from highly electron-rich character of metallic Pt species and the presence of surface reductive Fe2+ species, thereby being helpful for the chemisorption and activation of carbonyl group in cinnamaldehyde. Moreover, strong interactions between green rust matrix and metallic Pt species could stabilize the surface Pt nanoparticles, thereby inhibiting the metal leaching during the above reaction. The present study illustrates the validity of support control in supported Pt catalysts via tuning the compositions of LDHs, and thus the electronic structure of active metal sites and catalytic performance in the selective hydrogenation of cinnamaldehyde.