Advanced Guareschi-Thorpe synthesis of pyridines in green buffer, and pH-controlled aqueous medium with ammonium carbonate.

Hydroxy-cyanopyridines are easily synthesized via an advanced version of the Guareschi-Thorpe reaction by either three-component condensation of alkyl cyanoacetate or cyanoacetamide with 1,3-dicarbonyls and ammonium carbonate in an aqueous medium. Reactions proceed productively to give the desired products in high yields. Simple mechanistic monitoring showed the role of (NH4)2CO3 as both a nitrogen source for the pyridine ring and the reaction promoter. This new multicomponent approach for pyridine synthesis is inexpensive, user-friendly, and eco-friendly, while green buffer conditions, versatility, precipitation of products in the reaction medium, and simple work-up are extra advantages.

Selective preparation of crystalline or fibrous nano-cellulose carboxylate to fabricate an anti-bacterial hydrogel in co-operation with ZnO and recycled gelatin.

Bio-polymeric based nano-composites and hydrogels are newsworthy nano-biomaterials. Herein, crystalline or fibrous nano-cellulose carboxylate (NCCC and NCCF) were selectively prepared via the controllable direct oxidative-hydrolysis of MC in alkaline NaClO2 at 1:2 mol ratio, 90 °C, and 24 h for NCCC and at 1:1 mol ratio, 70 °C, and 20 h for NCCF. Characterization of NCCC and NCCF were performed by comparative Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and energy dispersive X-ray spectroscopy (EDS). Then, NCCC was cross-linked to the recycled gelatin (Gel) from the medicine capsules and the as-prepared nano-ZnO by maleic anhydride (MA) to give the novel hydrogel Gel/MA/NCCC/nano-ZnO. Nano-ZnO plays multi-roles in this hydrogel preparation, as either catalyst for the esterification of cellulose hydroxyls and amidation of gelatin amino groups or as the anti-bacterial part of hydrogel. The in vitro anti-bacterial activity results against the three gram-negative and gram-positive bacteria by well diffusion method confirmed Gel/MA/NCCC/nano-ZnO as an antibacterial agent with the activity order of P. aeruginosa > S. aureus > E. coli. The top anti-bacterial activity of this hydrogel against the gram-negative resistant bacteria of P. aeruginosa suggests its potential for biomedical applications.

Microwave-assisted preparation of ZnFe2O4@methyl cellulose as a new nano-biomagnetic photocatalyst for photodegradation of metronidazole.

In the present study, ZnFe2O4@methyl cellulose (MC) nano-biomagnetic photocatalyst was rapidly prepared based on a microwave-assisted method. FTIR, FESEM, EDS, UV-DRS, XRD, and VSM were performed to characterize the structure of as-prepared ZnFe2O4@MC. The removal efficiency of Metronidazole (MNZ) degradation was 92.65% and 71.12% in synthetic and real samples under optimal conditions, respectively. The removal efficiency of TOC was also reported to be 77.87% under optimal conditions. The kinetic linear models showed that the photocatalytic degradation of MNZ follows either a pseudo-first-order kinetic or the Langmuir-Hinshelwood model. The correlation coefficients (R2) were 0.92, 0.97, 0.99, and 0.94, respectively at 5, 10, 20, and 30 mg/L. The equilibrium adsorption coefficient (KL-H) of the Langmuir-Hinshelwood model and the superficial reaction rate constant (Kc) were 0.633 Lmg-1 and 0.203 mg/L min-1, respectively. The participation of active species such as holes and hydroxyl and superoxide radicals was studied during MNZ photodegradation with organic and inorganic radical scavengers. Finally, the nano-biomagnetic catalyst could be reused for six further runs without remarkable changes in catalytic efficiencies. In this study, we present a new magnetic nanocomposite and a novel strategy for antibiotic removal from aqueous media.

Photocatalytic degradation of ciprofloxacin using CuFe2O4@methyl cellulose based magnetic nanobiocomposite.

Herein, magnetically separable CuFe2O4@methyl cellulose (MC) as a novel magnetic nanobiocomposite photocatalyst was synthesized with a facile, rapid, green, and new microwave-assisted method. After that, CuFe2O4@MC was characterized with FESEM, EDS, FT-IR, XRD, TGA, and VSM techniques. To measure CuFe2O4@MC photocatalytic activity, ciprofloxacin (CIP) removal ability of CuFe2O4@MC was investigated under the conditions such as initial CIP concentrations (3, 5, 7, and 9 mg/L), pHs (3, 7, and 11), photocatalyst loadings (0.025, 0.05, 0.1, 0.2, 0.3, and 0.4 g), and irradiation time (15, 30, 45, 60, 75, and 90 min). Kinetic process was evaluated with the pseudo-first order and the Langmuir-Hinshelwood models. CIP concentration was measured with high performance liquid chromatography (HPLC). The maximum CIP removal efficiency in the optimal conditions which contained pH = 7, CIP initial concentration of 3 mg/L, photocatalyst loading of 0.2 g, and at irradiation time 90 min was achieved 72.87 % and 80.74 % from real and synthetic samples, respectively. Also, COD removal efficiency in the optimal conditions was achieved 68.26 %. Furthermore, the CuFe2O4@MC reusability and chemical stability were examined and 73.78 % of CIP was degraded after the fourth cycle. Advantages of this technique were as follows: •CuFe2O4@MC as a new nanobiomagnetic photocatalyst was synthesized with a facile, fast, and green method and were characterized with FESEM, EDS, FT-IR, XRD, TGA, and VSM techniques.•Ferromagnetic property and pure-phase spinel ferrites of CuFe2O4@MC were confirmed and significant photocatalytic activity of CuFe2O4@MC was observed.•Easily gathering, reusability and good chemical stability were interests of this nanobiomagnetic photocatalyst.

Urease immobilization on magnetic micro/nano-cellulose dialdehydes: Urease inhibitory of Biginelli product in Hantzsch reaction by urea.

Micro/nano celluloses (MC)/NC) were magnetized by nanoγ-Fe2O3 into the nanoγ-Fe2O3@MC (NMMC) and nanoγ-Fe2O3@NC (NMMC) which oxidized to NMMCD and NMNCD dialdehydes for Schiff-base immobilization of urease as NMMCD/urease and NMMCD/urease. The relative enzyme-activity of the immobilized ureases were comparable with the free-urease, although 75%-80% of the enzyme activity preserved for NMMCD/urease and NMNCD/urease after six cycles. The compared catalytic activities of the NMMCD/urease and NMMCD/urease in Biginelli/Hantzsch reactions in water at 60 °C surprised us by 100% selectivity for the Biginelli product 3,4-dihydropyrimidin-2(1H)-one (DHPM1). With the superiority of NMNCD/urease, this high selectivity using immobilized ureases is owing to the admirable urease inhibitory of the formed Biginelli product DHPM1 by urea condensation instead of urea hydrolysis. The robust enzyme inhibitory of the DHPM1 for free urease was also confirmed by phenol red test to show the deactivation of enzyme for enzymatic hydrolysis of urea and ammonia production in water.

A microwave assisted method to synthesize nanoCoFe2O4@methyl cellulose as a novel metal-organic framework for antibiotic degradation.

In this research, magnetically separable nanoCoFe2O4@methyl cellulose (MC) as a novel metal-organic framework was designed by a facile, fast, and new microwave-assisted method and then characterized. To assay the photocatalytic activity of nanoCoFe2O4@MC, its ability in metronidazole (MNZ) removal was investigated by considering the effect of some variables such as initial MNZ concentrations (5-20 mg/L), pH (3-11), nanophotocatalyst loading (0.0-0.4 g), and reaction time (15-120 min). The kinetic performance of the process was assessed by the pseudo-first order and Langmuir-Hinshelwood models. The concentration of MNZ was determined by high performance liquid chromatography. The optimal conditions for the maximum MNZ removal efficiency (85.3%) included pH of 11, MNZ concentration of 5 mg/L, photocatalyst loading of 0.2 g, and irradiation time of 120 min. Moreover, the reusability and chemical stability of nanoCoFe2O4@MC were studied. MNZ was successfully degraded at a rate of 77.58% in the fourth run. Advantages of this technique were as follows: •A facile, fast, and new microwave-assisted method was developed to synthesize nanoCoFe2O4@MC as a new nanobiomagnetic photocatalyst.•Pure-phase spinel ferrites, spherical particle morphology with smaller agglomeration, and ferromagnetic nature of nanoCoFe2O4@MC were confirmed.•NanoCoFe2O4@MC displayed a significant photocatalytic activity in the photocatalytic degradation of MNZ; moreover, it was easily separated by a magnet and exhibited good chemical stability.

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 ±â€¯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.

Urease covalently immobilized on cotton-derived nanocellulose-dialdehyde for urea detection and urea-based multicomponent synthesis of tetrahydro-pyrazolopyridines in water.

The urease Schiff-base covalently bonded to the designed high-content nanocellulosedialdehyde (HANCD) prepared from cotton-derived nanocellulose (NC) via tandem acid-hydrolysis and periodate-oxidation reactions was termed HANCD@urease. No change in the aldehyde content of HANCD after Schiff-base bonding to urease and similarity in the relative enzyme activities for HANCD@urease and free enzyme supported that the preparation conditions for HANCD-loaded urease are mild enough to prevent denaturation of the enzyme. As the immobilized urease showed higher stability and reusability versus free enzyme, the HANCD@urease was efficiently used to determine the urea concentration in aqueous solutions and blood serum samples. Alternatively, the catalytic efficiency of the HANCD@urease was demonstrated for the production of ammonia from urea in the multicomponent synthesis of 3,5-dimethyl-4-aryl-1,4,7,8-tetrahydrodipyrazolo[3,4-b:4',3'-e]pyridines (THPPs) in water. This new environment-friendly urea sensor showed 90% preservation of the enzyme activity after the six cycles of reuse in enzymatic reactions, while its catalytic activity in the reaction of benzaldehyde, hydrazine hydrate, and alkyl acetoacetate with urea instead of hygroscopic ammonium salts did not change significantly after the sixth run. Detection and production of ammonia by a bio-compatible sensor and catalyst under mild conditions are features of this new green protocol.

Scalable preparation, characterization, and application of alkali-treated starch as a new organic base catalyst.

Preparation, characterization, and application of alkali starch (AS) given by dry co-grinding of starch and alkali is described in this work. Grinding using a mortar (agate) and pestle or, more conveniently, a ball mill has been found to be satisfactory for the preparation of the AS. The AS products were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) and x-ray fluorescence (XRF) analyses. The base capacities of ASs were 4.25-4.45 mmol/g, respectively. AS is a low cost and easy to handle base catalyst that showed promising catalytic performance in the synthesis of a dihydroquinazoline-based antibacterial drug that involves tandem hydration or decarboxylative amidation, imination, and Aza-Michael reactions.

Deep eutectic liquid organic salt as a new solvent for liquid-phase microextraction and its application in ligandless extraction and preconcentraion of lead and cadmium in edible oils.

Deep eutectic liquid organic salt was used as the solvent and a liquid phase microextraction (DES-LPME) combined with electrothermal atomic absorption spectrometry (ETAAS) was developed for separation, preconcentration and determination of lead and cadmium in edible oils. A 4:1 mixture of deep eutectic solvent and 2% nitric acid (200 µL) was added to an oil sample. The mixture was vortexed and transferred into a water bath at 50 °C and stirred for 5 minutes. After the extraction was completed, the phases were separated by centrifugation, and the enriched analytes in the deep eutectic solvent phase were determined by ETAAS. Under optimized extraction conditions and for an oil sample of 28 g, enhancement factors of 198 and 195 and limits of detection (defined as 3 Sb/m) of 8 and 0. 2 ng kg(-1) were achieved for lead and cadmium respectively. The method was successfully applied to the determination of lead and cadmium in various edible oils.