Extraction of Kaempferitrin and Astragalin from Justicia Spicigera by Supercritical Fluid Extraction and Its Comparison with Conventional Extraction

A study of supercritical fluid CO2 extraction of kaempferitrin (KM) and astragalin (KG) from Justicia spicigera (muicle) was conducted. A 33 Box-Behnken design was used to analyze the effects of pressure (200-300 bar), temperature (40-60° C), and co-solvent flow rate (0.5-1.0 mL/min). The highest KM and KG concentration were achieved at a pressure of 300 bar, a temperature of 60° C, and co-solvent flow rate of 1.0 mL/min (ethanol 99.5 %), with a constant CO2 flow rate of 5 mL/min and extraction time of 180 min. Under these conditions, the experimental values for KM and KG (115.08±2.81 and 56.63±9.02 mg/100 g of dry powder, respectively) were similar to those calculated by the models (109.0 and 44.07 mg/100 g of dry powder, respectively). The use of 70 % ethanol as co-solvent in the supercritical extraction process considerably improved the yields of KM and KG (562.71±156.85 and 79.90±18.03 mg/100 g of dry powder, respectively) compared to the 99.5 % ethanol extractions. The conventional extraction showed the highest yields of KM and KG (574.20±65.10 and 113.10±15.06 mg/100 g of dry powder, respectively) at 70° C and extraction time of 120 min. Adequate yields were achieved of KM and KG by supercritical fluid extraction compared with conventional extraction (98 and 70 %, respectively); therefore supercritical fluid extract of J. spicigera could be used in the development of functional foods, as well as its possible use in traditional medicine by the health professionals.

A sustainable strategy for the straightforward preparation of 2H-azirines and highly functionalized NH-aziridines from vinyl azides using a single solvent flow-batch approach

The reported flow-batch approach enables the easy preparation of 2H-azirines and their stereoselective transformation into highly functionalized NH-aziridines, starting from vinyl azides and organolithium compounds. The protocol has been developed using cyclopentyl methyl ether (CPME) as an environmentally benign solvent, resulting into a sustainable, safe and potentially automatable method for the synthesis of interesting strained compounds.

Impact of blends of aqueous amines on absorber intercooling for post combustion CO2 capture system

Climate change is the biggest challenge of this century due to the global consequences of human activities on the ecosystem resulting in global warming. The emissions of greenhouse gases, mainly CO2 from the combustion of fossil fuels in the power plant is the main cause of global warming and to mitigate these emissions is the foremost challenge. Nowadays, the most preferred method is post combustion chemical absorption using amine-based solvents. However, high energy requirements for this method restrict its deployment. An efficient approach used for the reduction of the high energy requirement of post combustion CO2 capture process was absorber intercooling. Therefore, this research evaluates the effect of two configurations of intercooled absorber such as “simple” and “advanced” intercoolers for CO2 capture integrated with natural gas combined cycle power plant using aqueous alkanolamines, such as 30 wt.% monoethanolamine and 50 wt.% methyl-diethanolamine and their blends. For pure methyl-diethanolamine case, at lean loading 0.01 intercooling configurations; simple and advanced shows the highest reduction of 21.01% and 22.82% in the specific reboiler duty, respectively in comparison to other blends at the expense of highest liquid solvent flow rate. Simple and advanced intercooling configurations shows optimum results for the case with 40% monoethanolamine and 60% methyl-diethanolamine in a blend with decrease of 9.19% and 17.28% in solvent flow rate and a decrease of 9.42% and 16.83% in specific reboiler duty required for 90% CO2 capture rate, respectively. For pure monoethanolamine case at lean loading 0.2 absorber intercooling does not offer significant results.

A Sustainable Strategy for the Straightforward Preparation of 2H-azirines and Highly Functionalized NH-aziridines from Vinyl Azides Using a Single Solvent Flow-Batch Approach

The reported flow-batch approach enables the easy preparation of 2H-azirines and their stereoselective transformation into highly functionalized NH-aziridines, starting from vinyl azides and organolithiums. The protocol has been developed using cyclopentylmethylether (CPME) as an environmentally responsible solvent, resulting into a sustainable, safe and potentially automatable method for the synthesis of interesting strained compounds.

APPLICATION OF THE ULTRASONIC GENERATOR IN THE EXTRACTOR AND DETERMINATION OF ITS ENERGY CONSUMPTION

An ultrasonic generator was used in the Soxhlet extractor. To evaluate the process, the solvent flow was examined. The influence of the flow time in the Soxhlet on the process was analyzed. The formula for the residence time of streaming particles in the apparatus is given. A standardized volume curve V was formed. The time required for the solvent to remain in the apparatus is important during the extraction process. The description of the structure of flows of mass metabolic processes also means that it allows you to determine the movement and distribution of substances in these flows. Therefore, we wrote a hydrodynamic model of flows in the Soxhlet in the form of equations that represent the change in time in the apparatus. Ways to accelerate the extraction process are considered. The advantages of each method have been explored. Ultrasonic acceleration was selected from the investigated method. The parameters of the generator for generating ultrasound are considered. A compatible generator was selected. Selected “High Power Ultrosonic Generator” 40 kHz, 1.2 kW because it uses less power and does not affect the balance of the device. If a generator with high parameters is selected, the effect on the balance of the device is determined. For large extractors, a high-performance ultrasonic generator is recommended. The schematic diagram of the selected generator is taken from the reference book. We have performed a complete extraction process to estimate the energy consumption of the process. It turned out that the process, carried out with the help of ultrasound, is fast and energy efficient. The experiments took over an hour to evaluate the process. While 10 ml of the substance was extracted from the extracted basil leaf for one hour, 15 ml of the substance was separated from the addition process by sonication for one hour. In each experiment, the mode was chosen the same. Graphs were drawn to compare the results.

Coupled flow and deformation fields due to a line load on a poroelastic half space: effect of surface stress and surface bending

In the past decade, many experiments have indicated that the surfaces of soft elastic solids can resist deformation by surface stresses. A common soft elastic solid is a hydrogel which consists of a polymer network swollen in water. Although experiments suggest that solvent flow in gels can be affected by surface stress, there is no theoretical analysis on this subject. Here we study the solvent flow near a line load acting on a linear poroelastic half space. The surface of this half space resists deformation by a constant, isotropic surface stress. It can also resist deformation by surface bending. The time-dependent displacement, stress and flow fields are determined using transform methods. Our solution indicates that the stress field underneath the line load is completely regularized by surface bending—it is bounded and continuous. For small surface bending stiffness, the line force is balanced by surface stresses; these forces form what is commonly known as ‘Neumann's triangle’. We show that surface stress reduces local pore pressure and inhibits solvent flow. We use our line load solution to simulate the relaxation of the peak which is formed by applying and then removing a line force on the poroelastic half space.

Production of starch nanoparticles through solvent-antisolvent precipitation in a spinning disc reactor

The spinning disc reactor (SDR) uses surface rotation to produce thin film flow with improved mixing and reduced residence times in chemical processing applications. Solvent-antisolvent precipitation is one such process that can benefit from these properties. This study investigates the film hydrodynamics and precipitation of starch nanoparticles by contacting starch dissolved in sodium hydroxide with ethanol as the antisolvent. One objective of this study is to understand how interactions of the disc surface topography (grooved and smooth) with other parameters such as liquid flowrate, antisolvent to solvent flow ratio and disc speed impact the mixing and precipitation processes. Results indicate that an increase in flow rate and rotational speed leads to smaller nano-particles and narrower size distributions, which is attributed to increased shear and instabilities within the liquid film. It was also observed that an increased antisolvent to solvent ratio caused a reduction in particle size, as increased antisolvent generated higher supersaturation. Results showed that although particle size was not significantly influenced by the disc texture, the size distribution was narrower and higher yields were obtained with the grooved disc surface. The grooved disc therefore offers the opportunity for higher throughput in the solvent-antisolvent precipitation of starch particles with better product quality.