Carlos J. Durán-Valle

Even though protection‐free protocols represent a key principle of green chemistry, both protection and deprotection routes are indispensable strategies in synthetic pursuits, especially towards highly functionalized pharmaceuticals and agrochemicals, often decorated by promiscuous OH or NH groups, among others. Herein a sustainable carbon‐based catalyst is reported that efficiently promotes the protection of 1,2‐diols as isopropylidene ketals under heterogeneous conditions, affording products in high conversion and yields. Grafting of sulfonate groups onto the high‐surface‐area carbon creates a solid acid catalyst with high performance for acetalization under mild thermal conditions. Interestingly, the same catalyst can be employed for the inverse deprotection step leading to the parent diols with comparable efficiency. Along with a detailed catalyst's characterization, critical issues related to catalyst loading, reaction scope, and selectivity were thoroughly optimized. The catalyst can be recycled, and no impurities caused by leaching could be observed.

This study analyzed the fabrication and characterization of polybenzoxazine/polydopamine/ceria as tertiary nanocomposites. To this end, a new benzoxazine monomer (MBZ) was fabricated based on the well-known Mannich reaction of naphthalene-1-amine, 2-tert-butylbenzene-1,4-diol and formaldehyde under ultrasonic-assisted process. Polydopamine (PDA) was used as dispersing polymer nanoparticles and surface modifier for CeO2 by in-situ polymerization of dopamine with the assistance of ultrasonic waves. Then, nanocomposites (NC)s were manufactured by in-situ route under thermal conditions. The FT-IR and 1H-NMR spectra confirmed the preparation of the designed MBZ monomer. The FE-SEM and TEM results showed the morphological aspects of prepared NCs and illustrated the distribution of CeO2 NPs in the polymer matrix. The XRD patterns of NCs showed the presence of crystalline phases of nanoscale CeO2 in an amorphous matrix. The TGA results reveal that the prepared NCs are classified as thermally stable materials.