Sulfonated PEG-intercalated montmorillonite [(Mt/PEG)-SO<Subscript>3</Subscript>H] as efficient and ecofriendly nanocatalyst for synthesis of α,α′-bis(substituted benzylidene)cycloalkanones

(Montmorillonite/PEG)-SO₃H nanocomposite was successfully prepared for the first time and introduced as a solid acid nanocatalyst. Initially, polyethylene glycol (PEG) polymeric chains were intercalated into interlayer spaces of montmorillonite. The resulting Mt/PEG nanocomposite with good mechanical and thermal stability was chosen as a useful clay mineral/polymer support for further modification with chlorosulfonic acid. Structural characterization of (Mt/PEG)-SO₃H was carried out using X-ray diffraction (XRD) analysis, Brunauer–Emmett–Teller (BET) measurements, Barrett–Joyner–Halenda (BJH) analysis, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier-transform infrared (FT-IR) spectroscopy. The results showed that PEG chains were intercalated into the clay mineral layers and that the Mt/PEG nanocomposite was successfully sulfonated. (Mt/PEG)-SO₃H nanocomposite exhibited high specific surface area and good stability up to around 150 °C, showing excellent potential for application as a recyclable nanocatalyst. (Mt/PEG)-SO₃H was used as an efficient and ecofriendly solid acid nanocatalyst for preparation of α,α′-bis(substituted benzylidene)cycloalkanones under solvent-free conditions, leading to many interesting findings. The excellent conversion values confirm that the catalyst has strong and sufficient acidic sites, which are responsible for its catalytic performance. The reaction under mild conditions (room temperature) with excellent yield, catalyst recyclability (up to ten times), and simple work-up procedure represent useful advantages of (Mt/PEG)-SO₃H for catalysis. Moreover, the reaction could be scaled up to 10 and 15 mmol scales.     

Constructing Environmental Radon Gas Detector and Measuring Concentration in Residential Buildings

Physics of Particles and Nuclei Letters - Background: From the health physics perspective, radon gas is one of the most dangerous gases in residential and business environments. According to the...     

A novel and efficient strategy for the synthesis of various carbamates using carbamoyl chlorides under solvent-free and grinding conditions using microwave irradiation

We present an efficient,fast and simple strategy of generating the intermediate carbamoyl chlorides from secondary amines using stoichiometric amounts of bis(trichloromethyl)carbonate(BTC) in solution and solvent-free conditions with excellent yields.The results obtained showed the yield increasing on whether a base was used.Finally,an efficient and rapid synthesis of variety carbamate derivatives was developed by the reaction with a high variety of different alcohols,phenols,diols and this intermediate at room temperature with grinding and in solvent-free conditions under microwave irradiation.The presence of various safe bases is shown to be effective in reducing the reaction times,increasing the yields and easing purification.The present method does not involve any hazardous phosgene.     

Sensitive amperometric detection of omeprazole and pantoperazole at electrodeposited nickel oxide nanoparticles modified glassy carbon electrode

Glassy carbon electrode modified with electrodeposited nickel oxide nanoparticles (NiOxNPs) was used as electrocatalyst for oxidation of omeprazole and pentoperazole in alkaline solution. The modified electrode exhibited efficient electrocatalytic activity for the oxidation of omeprazole and pentoperazole with relatively high sensitivity, excellent stability, and long lifetime. Hydrodynamic amperometric method is used for determination of selected analytes. Under optimized condition, the linear concentration range, detection limit, and sensitivity of modified electrode toward omeprazole detection are 4.5–120 μM, 0.4 μM (at signal to noise 3), and 40.1 nA μM⁻¹ cm⁻², respectively. For pantoperazole, hydrodynamic amperometric determination yielded calibration curve with linear range of 2.5–180 μM, detection limit of 0.2 μM, and sensitivity of 39.2 nA μM⁻¹ cm⁻², respectively. The proposed method was successfully applied to pentoperazole and omeprazole determination in drug samples.     

Flame-retardancy and photocatalytic properties of cellulosic fabric coated by nano-sized titanium dioxide

We have investigated the effect of titanium dioxide as a durable finish on the flammability and photocatalytic self-cleaning of cellulosic fabric. Nano-sized titanium dioxide particles were successfully synthesized and deposited onto cellulosic fibers with good compatibility, significant photocatalytic self-cleaning activity, and flame-retardancy properties using the sol–gel process at low temperature. The photocatalytic activity was tested by measuring the photodegradation of methylene blue under ultraviolet–visible illumination, and also flame-retardancy effect was tested by flammability tester. The samples have been characterized by several techniques such as scanning electron microscopy, transmission electron microscopy, diffuse reflectance spectroscopy, X-ray diffraction, and thermogravimetric analysis. The titanium dioxide nanoparticles with 10–20 nm in size have been found to form a homogeneous thin film on the fiber surface which shows efficient photocatalytic and flame-retardancy properties. This preparation technique can also be applied to new fabrics to create self-cleaning and flame-retardancy properties in them.     

Encapsulation of L-dopa and catechol in bovine serum albumin nanocarrier using desolvation method and their in vitro release studies

In the current study, the interaction between L-dopa and bovine serum albumin (BSA) as well as catechol and BSA is investigated separately. In order to achieve the optimum values for encapsulated efficiency (EE), the content of crosslinker/BSA, organic/aqueous phase, drug/BSA, stirring rate, and pH were closely studied taking the advantage of Taguchi method. Particle characterization was carried out using transmission electron microscopy and dynamic light scattering techniques. The most appropriate catechol and L-dopa nanoparticles in the size range of 100 nm and 65 nm, respectively, and at optimized conditions of drug/BSA = 0.1, pH = 7.4, crosslinker/BSA = 0.084, organic/aqueous phase = 4 and stirring rate 400 rpm were obtained. The most favorable EE (encapsulation efficiency) and LC (loading capacity) for L-dopa and catechol was estimated to be 88.1% and 83.6%, respectively, and the calculated LC% was achieved 93.4% and 89.7% for L-dopa and catechol, respectively. The chromatographic analyses results were also found to be in a good agreement with the obtained data for the calculated EE% and LC% values. in vitro release of loaded drugs from nanoparticles in phosphate-buffered saline (pH = 7.4, incubated at 37 ± 0.5°C under stirring rate of 100 rpm) showed the release of 78% catechol and 89% L-dopa during 480 min and 510 min, respectively.