The first example of heterogeneous oxidation of secondary amines by tungstate-exchanged Mg-Al layered double hydroxides: a green protocol

Tungstate exchanged Mg-Al layered double hydroxides a as recyclable heterogenised catalyst along with H2O2 as an oxidant for the oxidation of sec-amines to nitrones is developed for the first time, Reactions proceed at a fast rate in aqueous media in a single step at room temperature in good to excellent yields. The heterogenised catalyst showed higher activity (TOF) over their homogeneous analogues and other heterogeneous catalysts reported so far. The obtained catalysts were well characterised by various instrumental techniques such as FT-IR spectroscopy, thermal analysis (TGA and DTA), powder XRD and chemical analysis. The catalyst can be reused for six cycles with consistent activity and selectivity

Esthetic Replacement of Maxillary Lateral Incisor with Mary Lever Prosthesis: A Novel Conservative Approach

Dentists often question the use of resin-bonded fixed partial dentures (RBFPDs) for reliable restoration of tooth-bound edentulous spaces. Initial attempts at bonding fixed partialdentures on teeth resulted in early failure due to debonding. In the 1980s and 1990s, improvements in preparation methods, metal alloys and bonding techniques made the RBFPD a more predictable option. This article provides a case report of a restoring a missing maxillary lateral incisor with modified Maryland with the advantages of being fixed to provide a stronger bond as well as being kinder to the periodontal tissues

ANN and RSM based Modeling of Moringa Stenopetala Seed Oil Extraction: Process Optimization and Oil Characterization

Moringa Stenopetala is a plant species that is endemic to the southern region of Ethiopia. It is primarily cultivated for its nutritional value and is considered an important food source. The present research aimed to analyse the physicochemical properties of Moringa Stenopetala seed oil (MSO) obtained through solvent extraction method utilising hexane as the solvent. The collection of seeds was conducted in Adama, which is situated in the East Shawa zone of Oromia, Ethiopia. Prior to the extraction procedure, the seeds' average moisture content, crude ash, fibre, protein, and oil content were analysed and found to be 6.27%, 7.8%, 2.7%, 26.5%, and 43.2%, respectively. Using the Response Surface Method (RSM) and Artificial Neural Network (ANN), the extraction process was modeled. The study utilised numerical solutions to determine the optimal process parameters for maximising oil yield during extraction. The results indicated that a particle size of 0.85mm, a temperature of 85°C, and an extraction time of 4.75 hours were the most effective parameters. Furthermore, an investigation was conducted on the physical and chemical properties of the oil obtained under optimised conditions

Novel Characterization Method of Biodiesel Produced from Soybean Oil using Thermogravimetric Analysis

The aim of this study was to demonstrate thermogravimetric analysis (TGA) as a potential method for monitoring biodiesel production. Soybean oil and commercial biodiesel were mixed in different proportions by weight. Mixtures of different biodiesel/soybean oil ratios were also created by interrupting a base-catalyzed transesterification process for producing biodiesel at various times. The mixtures produced by both approaches were analyzed with TGA. The results were then compared with data obtained by proton nuclear magnetic resonance spectroscopy ( 1HNMR spectroscopy). The relative weight losses in both sets of mixtures we generated correlated well to the proportion of biodiesel present in the sample. The results from both analytical methods were in good agreement and within a deviation of 5%. Thus, TGA is a simple, convenient and economical method for monitoring biodiesel production

Henry reactions catalysed by modified Mg-Al hydrotalcite: an efficient reusable solid base for selective synthesis of β-nitroalkanols

Henry reactions have been performed for the first time with suitably activated Mg-Al hydrotalcite as catalyst in quantitative yields in the liquid phase under mild reaction conditions and with low reaction times. Exclusive synthesis of β-nitroalkanols (3) is realised by the compatible basic Bronsted hydroxy sites of the modified hydrotalcite. Reusability with consistent activity and selectivity for a number of cycles is established indicating that the hydrated hydrotalcite employed here is a potentially eco-friendly catalyst which can replace soluble bases in commercial synthesis

Direct conversion of azides and benzyl carbamates to t-butyl carbamates using polymethylhydrosiloxane and Pd-C

One step direct conversion of azides and benzyl carbamates to t-butyl carbamates is achieved using inexpensive and safe hydride source namely polymethylhydrosiloxane (PMHS) under Pd-C catalysis

Enhancing Biodiesel Production from Soybean Oil using Ultrasonics

The objective of the study was to determine the effect of high-powered ultrasonics on enhancing biodiesel production from soybean oil. In this study, soybean oil was mixed with methanol and sodium hydroxide and was sonicated at 3 amplitude levels of the ultrasonic (60µm pp , 120µm pp and 180µm pp ) in a pulse mode (5 seconds on/25 seconds off). The results were compared to a control group where the same reactant composition was allowed to react at 60ºC for intervals ranging from 5 minutes to 1 hour with no ultrasonic treatment. It was observed that ultrasonic treatment resulted in a 96% yield (percent conversion to biodiesel) in less than approximately 90 s; compared to 5 to 10 minutes for the control sample. The highest yield was obtained from sonicating the mixture at 120µm pp amplitude.This is an ASABE Meeting Presentation, Paper No. 084374.</p

Pressure-induced phase transitions of hydrotalcite by electrical resistivity, structural and thermal studies

We report for the first time the high-pressure electrical resistivity measurements on synthetic hydrotalcite up to 6 GPa at room temperature. Pressure dependence of the electrical resistivity of synthetic hydrotalcite reveals two pressure- induced irreversible phase transitions at about 1 and 3 GPa, respectively. The first transition was accompanied by decrease of electrical resistivity 30% at about 1.5 GPa and the second phase transformation was characterized by observing a first-order decrease of electrical resistivity (about 60%) at ~2.5-3 GPa. The high-pressure phases were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopic, and differential thermal analysis studies on the pressure-quenched samples. The spectroscopic and structural studies on the pressure-quenched samples show that hydrotalcite transforms irreversibly to manasseite phase at about 1.5 GPa and further compression leads to pressure-induced amorphization of the manasseite phase of the sample at pressures 4-4.5 GPa. The thermal (DTA/TG) studies also confirm the different high-pressure modifications of hydrotalcite