Amphiphilic Self-Assembled Polymeric Copper Catalyst to Parts per Million Levels: Click Chemistry

Self-assembly of copper sulfate and a poly­(imidazole–acrylamide) amphiphile provided a highly active, reusable, globular, solid-phase catalyst for click chemistry. The self-assembled polymeric Cu catalyst was readily prepared from poly­(<i>N</i>-isopropylacrylamide-<i>co</i>-<i>N</i>-vinylimidazole) and CuSO₄ via coordinative convolution. The surface of the catalyst was covered with globular particles tens of nanometers in diameter, and those sheetlike composites were layered to build an aggregated structure. Moreover, the imidazole units in the polymeric ligand coordinate to CuSO₄ to give a self-assembled, layered, polymeric copper complex. The insoluble amphiphilic polymeric imidazole Cu catalyst with even 4.5–45 mol ppm drove the Huisgen 1,3-dipolar cycloaddition of a variety of alkynes and organic azides, including the three-component cyclization of a variety of alkynes, organic halides, and sodium azide. The catalytic turnover number and frequency were up to 209000 and 6740 h^–1, respectively. The catalyst was readily reused without loss of catalytic activity to give the corresponding triazoles quantitatively

Extraction of penicillin G from aqueous solution using a membrane contactor: numerical investigation

In the current study, the treatment of pharmaceutical wastewater containing penicillin G treatment using a hollow fibre membrane contactor was investigated. A mathematical model based on the finite element method was developed. The extraction was performed using Shellsol TK as organic solvent containing 5% Aliquat 336. The effect of feed pH, flow rate and temperature were examined for the extraction of penicillin G from aqueous solution. The results showed that there is reasonable good agreement between experimental data and modelling values. It was found that increasing temperature from 10 -C to 30 -C increases the penicillin G extraction from 33% to 54%. Also, penicillin G extraction was decreased from 34.7% to 25.1% with increasing pH from 5.5 to 6.5 while it grew to 45.8% when the pH of feed solution was 7. Furthermore, the results showed the diffusive flux is favourable for the system and penicillin G extraction but the convective flux has negative impact on the system in terms of penicillin G extraction. It was concluded that a hollow fibre membrane contactor has the potential for use in wastewater treatment through it is important to improve diffusive flux in the system to enhance penicillin G extraction

Recent advancement of ullmann condensation coupling reaction in the formation of aryl-oxygen (C-O) bonding by copper-mediated catalyst

Transition metal-catalyzed chemical transformation of organic electrophiles and organometallic reagents belong to the most important cross coupling reaction in organic synthesis. The biaryl ether division is not only popular in natural products and synthetic pharmaceuticals but also widely found in many pesticides, polymers, and ligands. Copper catalyst has received great attention owing to the low toxicity and low cost. However, traditional Ullmann-type couplings suffer from limited substrate scopes and harsh reaction conditions. The introduction of homogeneous copper catalyst with presence of bidentate ligands over the past two decades has totally changed this situation as these ligands enable the reaction promoted in mild condition. The reaction scope has also been greatly expanded, rendering this copper-based cross-coupling attractive for both academia and industry. In this review, we will highlight the latest progress in the development of useful homogeneous copper catalyst with presence of ligand and heterogeneous copper catalyst in Ullmann type C-O cross-coupling reaction. Additionally, the application of Ullmann type C-O cross coupling reaction will be discussed

Adsorption of thallium from wastewater using disparate nano-based materials: A systematic review

Development of promising technologies to remove thallium as a highly poisonous contaminant is of great attention to guarantee the sustainable supplement of safe potable water and human well-being all around the world. Recently, adsorption has been introduced as a noteworthy technique to remove trace amount of thallium. In the past, the rate of thallium removal using the adsorption technique was relatively low due to the fact that this method was significantly influenced by the co-existing cations. To overcome this problem, more promising adsorbents such as nano-based materials have been developed. These adsorbents have shown great potential in the process of thallium removal due to their large surface area and superior selectivity. The main objective of this paper is to present a state-of-the-art review about the potential of nano-based form of disparate materials (i.e., titanium compounds, MnO2, ZnO, Al2O3 and multiwall carbon nanotubes) to separate thallium from water/waste water sources. Then, a systematic overview about acute/chronic toxicities of thallium for humans is aimed to be provided. Throughout the review, the authors aim to compare the negative and positive aspects of each treatment technique and offer promising technologies for thallium removal. At the end, an outlook on the recent advancements in the adsorption process of thallium using nanomaterials is provided

Synthesis of multi‑organo‑functionalized fibrous silica KCC‑1 for highly efficient adsorption of acid fuchsine and acid orange II from aqueous solution

Multi-functionalized fibrous silica KCC-1 (MF-KCC-1) bearing amine, tetrasulfide, and thiol groups was synthesized via a post-functionalization method and fully characterized by several methods such as FTIR, FESEM, EDX-Mapping, TEM, and N2 adsorption–desorption techniques. Due to abundant surface functional groups, accessible active adsorption sites, high surface area (572 m2 g−1), large pore volume (0.98 cm3 g−1), and unique fibrous structure, mesoporous MF-KCC-1 was used as a potential adsorbent for the uptake of acid fuchsine (AF) and acid orange II (AO) from water. Different adsorption factors such as pH of the dye solution, the amount of adsorbent, initial dye concentration, and contact time, affecting the uptake process were optimized and isotherm and kinetic studies were conducted to find the possible mechanism involved in the process. For both AF and AO dyes, the Langmuir isotherm model and the PFO kinetic model show the most agreement with the experimental data. According to the Langmuir isotherm, the calculated maximum adsorption capacity for AF and AO were found to be 574.5 mg g−1 and 605.9 mg g−1, respectively, surpassing most adsorption capacities reported until now which is indicative of the high potential of mesoporous MF-KCC-1 as an adsorbent for removal applications

Novel bimodal micro-mesoporous Ni50Co50-LDH/ UiO-66-NH2 nanocomposite for Tl(I) adsorption

Ni50Co50-layered double hydroxide/UiO-66-NH2 metal–organic framework nanocomposite (Ni50Co50-LDH/UiO-66-NH2 NC) was synthesized through a facile ultrasonic-assisted hydrothermal method. UiO-66-NH2 MOF nanocrystals were in situ grown on the surface of ultrathin 2-dimensional functionalized Ni50Co50-LDH nanosheets. Using this method, a uniform nanocomposite architecture was obtained by uniformly distributing MOF nanocrystals on Ni50Co50-LDH. The synthesized LDH/MOF NC possesses essential properties of potential nano adsorbent such as high surface area (907 m2 g 1 ), large pore volume (0.91 cm3 g1), bimodal micro mesoporous structure, and chemical functionality. Accordingly, Ni50Co50-LDH/UiO-66-NH2 NC was used as an adsorbent for the uptake of toxic thallium (I) from water. Isotherm, thermodynamic, and kinetic studies were conducted to gain a better insight into the adsorption mechanism (s) involved in the removal process. Langmuir and pseudo-first-order models present a better fit to the isotherm and kinetic data, respectively, and the maximum Langmuir adsorption capacity was found to be 601.3 mg g 1 after non-linear fitting analysis (pH=7.0, solution volume=30 mL, initial thallium (I) concentration=50 mg L–1, contact time=15 min, solution temperature=293 K

A novel and facile green synthesis method to prepare LDH/MOF nanocomposite for removal of Cd(II) and Pb(II)

To date, many nanoadsorbents have been developed and used to eliminate heavy metal contamination, however, one of the challenges ahead is the preparation of adsorbents from processes in which toxic organic solvents are used in the least possible amount. Herein, we have developed a new carboxylic acid-functionalized layered double hydroxide/metal–organic framework nanocomposite (LDH/MOF NC) using a simple, efective, and green in situ method. UiO-66-(Zr)- (COOH)2 MOF nanocrystals were grown uniformly over the whole surface of COOH-functionalized Ni50Co50-LDH ultrathin nanosheets in a green water system under a normal solvothermal condition at 100 °C. The synthesized LDH/MOF NC was used as a potential adsorbent for removal of toxic Cd(II) and Pb(II) from water and the infuence of important factors on the adsorption process was monitored. Various non-linear isotherm and kinetic models were used to fnd plausible mechanisms involved in the adsorption, and it was found that the Langmuir and pseudo-frst-order models show the best agreement with isotherm and kinetic data, respectively. The calculated maximum adsorption capacities of Cd(II) and Pb(II) by the LDH/MOF NC were found to be 415.3 and 301.4 mg g−1, respectively, based on the Langmuir model (pH= 5.0, adsorbent dose = 0.02 g, solution volume = 20 mL, contact time = 120 min, temperature= 25 ℃, shaking speed 200 rpm)

Selective synthesis of methanol by photoelectrocatalytic reduction of CO2 over PANI-CuFe2O4 hybrid catalyst

In this work, a hybrid photocatalyst, PANI-CuFe2O4 was synthesized, characterized and used as a photocathode for the photoelectrocatalytic (PEC) reduction of CO2 to methanol selectively under 470 nm wavelength light irradiation at applied potential -0.4 V vs NHE. The PEC results showed that the combination of PANI with CuFe2O4 could increase the rate of PEC CO2 reduction to methanol owing to the increase of CO2 chemisorption at the photocathode surface and at the same time by facilitating the separation of photogenerated electron-hole (e-/h+) pairs during CO2 reduction. The rate of methanol formation was found maximum as 49.2 μmole g-1.h-1 with 73% Faradaic efficiency. The incident photon current efficiency (IPCE) and quantum efficiency (QE) for PEC CO2 reduction was achieved as 7.11% and 23.9% respectively. The PEC results demonstrated that the bias potential played a significant role in the separation of e-/h+ pairs and enhanced the PEC CO2 reduction activity of the hybrid photocatalyst

Highly active cellulose-supported poly(hydroxamic acid)–Cu(II) complex for Ullmann etherification

Highly active natural pandanus-extracted cellulose-sup ported poly(hydroxamic acid)−Cu(II) complex 4 was synthesized. The surface of pandanus cellulose was modified through graft copolymerization using purified methyl acrylate as a monomer. Then, copolymer methyl acrylate was converted into a bidentate chelating ligand poly(hydroxamic acid) via a Loosen rearrangement in the presence of an aqueous solution of hydroxylamine. Finally, copper species were incorporated into poly- (hydroxamic acid) via the adsorption process. Cu(II) complex 4 was fully characterized by Fourier transform infrared (FTIR), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray (EDX), transmission electron microscopy (TEM), inductively coupled plasma optical emission spectrometry (ICP-OES), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses. The cellulose-supported Cu(II) complex 4 was successfully applied (0.005 mol %) to the Ullmann etherification of aryl, benzyl halides, and phenacyl bromide with a number of aromatic phenols to provide the corresponding ethers with excellent yield [benzyl halide (70−99%); aryl halide (20−90%)]. Cu(II) complex 4 showed high stability and was easily recovered from the reaction mixture. It could be reused up to seven times without loss of its original catalytic activity. Therefore, Cu(II) complex 4 can be commercially utilized for the preparation of various ethers, and this synthetic technique could be a part in the synthesis of natural products and medicinal compounds

Magnetically recyclable Schiff-based palladium nanocatalyst [Fe3O4@SiNSB-Pd] and its catalytic applications in Heck reaction

A magnetically separable palladium nanocatalyst has been synthesized through the immobilization of palladium onto 3-aminopropylphenanthroline Schiff based functionalized silica coated superparamagnetic Fe3O4 nanoparticles. The nanocatalyst (Fe3O4@SiNSB-Pd) was fully characterized using several spectroscopic techniques, such as FT-IR, HR-SEM, TEM, XRD, ICP, and XPS. The microscopic image of Fe3O4 showed spherical shape morphology and had an average size of 150 nm. The Pd-nanoparticles exhibited an average size 3.5 ± 0.6 nm. The successful functionalization of Fe3O4@SiNSB-Pd was identified by FT-IR spectroscopy and the appearance of palladium species in Fe3O4@SiNSB-Pd was confirmed by XRD analysis. While XPS has been utilized for the determination of the chemical oxidation state of palladium species in Fe3O4@SiNSB-Pd. Several activated and deactivated arene halides and olefines were employed for Mizoroki-Heck cross-coupling reactions in the presence of Fe3O4@SiNSB-Pd, each of which produced the respective cross-coupling products with excellent yields. The Fe3O4@SiNSB-Pd shows good reactivity and reusability for up to seven consecutive cycles.</p