Nuray Yılmaz Baran

Production of novel palladium nanocatalyst stabilized with sustainable chitosan/cellulose composite and its catalytic performance in Suzuki-Miyaura coupling reactions

In this study, we designed a new palladium nanocatalyst on chitosan/cellulose composite for the first time to increase the use of sustainable polysaccharides, which are cheap, non-toxic, environmental friendly, abundant in nature, and can be used as support materials for metallic nanoparticles. Physicochemical characterization of fabricated palladium nanocatalyst was illuminated with FT-IR, TG/DTG, SEM/EDAX, XRD, and ICP-OES analyses. Pd nanoparticles were found to be almost spherically structured, and the average particle size was 26-30nm. Then catalytic performance of the designed nanocatalyst was investigated in the synthesis of a series of biphenyl compounds via the Suzuki-Miyaura reaction by using the green method which is conducted in a very short-time, under low temperature, and without the presence of any toxic chemical solvents (e.g., 5min treatment in microwave oven at 400W at 50°C). As a result of the tests, palladium nanocatalyst showed excellent catalytic performance with high conversion yields for a wide range of substrates and with a very low catalyst loading for the Suzuki reactions. Sustainability performance of palladium nanocatalyst was also studied, and it is found that the catalyst was able to be recycled for eight successive runs.

Efficient adsorption of hemoglobin from aqueous solutions by hybrid monolithic cryogel column

In this study, a supermacroporous poly(2-hydroxyethyl methacrylate) (PHEMA)-based Cu2+-attached bentonite particles embedded hybrid monolithic cryogel (Cu2+-ABPs EHMC) was prepared by radical cryo-copolymerization of HEMA with N,N-methylene-bis-acrylamide (MBAAm) as a cross-linker directly in a plastic syringe in the presence of Cu2+-ABPs, and used for hemoglobin (Hb) separation from aqueous solution. Due to the naturally abundant hydroxyl groups on bentonite, Cu2-attached bentonite particles (Cu2+-ABPs) embedded hybrid monolithic cryogel (HMC) showed a good adsorption performance for Hb, covering an excellent adsorption capacity of 521.6mg/g bentonite in phosphate buffer at pH6.0 with a flow rate of 0.5mL/min, fast binding stability within 60min, well selectivity and reversibility. Compared with other adsorbent systems used for protein separation, this sorbent has many advantages such as excellent adsorption performance, ease of preparation, suitable, effective and environment-friendly to perform, which can serve as a more sustainable material in protein separation and purification.

An easily recoverable and highly reproducible agar-supported palladium catalyst for Suzuki-Miyaura coupling reactions and reduction of o-nitroaniline

Polysaccharides are excellent support materials for catalytic systems due to their superior metal binding capacity, high mechanical strength, and green nature. Among the polysaccharides, agar can be considered a good support material for catalytic reactions from the point of its low cost, easy availability, high thermal durability, and biodegradability. In this study, agar-supported palladium catalyst (AG-Pd) was designed for the first time, and then its catalytic performance was tested towards (i) Suzuki-Miyaura coupling reactions and (ii) catalytic reduction of o-nitroaniline to o-phenylenediamine under mild reaction conditions. Additionally, the reproducibility of the designed AG-Pd catalyst was investigated in both catalytic reactions, and the tests showed that the catalyst could be reused many times. AG-Pd catalyst displayed excellent selectivity and efficiency in Suzuki-Miyaura coupling reactions in only 6u202fmin under solvent-free media. In addition, AG-Pd catalyst provided good catalytic reduction by completely reducing o-nitroaniline in 90u202fs at room temperature. These findings reveal that agar is a good support material, and it can be used for different catalytic systems as a support.