Preparation of nano-alkalinecellulose carboxylates (NACCs) as the methylene blue sorbent and as the catalyst for the large-scale nifedipine synthesis.

In this work, various new nano-alkalinecellulose carboxylates (NACCs) were prepared by oxidative hydrolysis of microalkalinecellulose (MACp) given from prewashed cotton. After the optimization of the reaction time, temperature, oxidant system, and oxidant loading, the new flake-shape anionic NACC24 with base capacity 10.8 mmol HO-/g was obtained from MACp at 50 °C. The characterized NACC24 and MACp were comparatively used as bio-sorbent for removal of methylene blue (MB) from wastewater and as the catalyst in the large-scale synthesis of nifedipine. With the Langmuir model and monolayer pseudo-second-order kinetic mechanism, the negatively charged polymer NACC24 represented high sorption capacity for the MB removal at 780 ± 10 mg/g. A high regeneration stability and 90.5% original efficiency was verified for the NACC24 after five consequence adsorption-desorption cycles, where acidic methanol and aqueous NaOH were used for the efficient desorption of electrostatically interacted MB to NACC24 and respective reactivation of the NACC24 for further runs. Besides, NACC24 showed a high catalytic activity in the base-catalyzed rapid synthesis of anti-hypertension nifedipine even after the five times reusing of catalyst.