Chemical Review and Letters
Volume:2 Issue: 3, Summer 2019

In this article, Entropy generation and enthalpy are investigated on the pipe wall in developed laminar flow for 7 cases. Variation of entropy generation and enthalpy are shown along the radius. Entropy generation and enthalpy along the radius are obtained. Heat transfer is increased with the flow of fluid through the pipe, in inlet of pipe points to the output. The amount of entropy generation in the pipes of higher temperature is more than other points. Enthalpy is proportional to temperature in surface variation of 7 cases. In the points of higher temperature in elementary cases, the enthalpy value is increasing and it is increasing in other cases. Fluctuations of enthalpy and entropy generation are producted in interface points of pipe surfaces. The diagram data can be used to measure the minimum entropy generation in pipe heat transfer. Minimum entropy generation is in surface whit high temperature. The enthalpy in centerline is constant and inlet enthalpy of the tube is greater than other point with higher temperatures in radial flow. The lowest enthalpy is obtained in tubes with lowest initial temperature (case 7). Minimum entropy generation is presented in surface whit high temperature at the beginning (case 1-3) or high at the ending (case 5-7).

CFCs containing volatile compounds are detrimental to atmospheric environment and to all living organisms. These compounds are frequently reported to be chemically stable/inert. Also their photodissociation reaction results to reasonable amount of Chlorine atoms formation in the stratospheric part of atmosphere. This eventually bring out depletion of Ozone (lives and properties protecting compound) in the stratosphere. In order to cope this environmental havoc, there is need to find substitutable compounds for CFCs and possibly predict their atmospheric effects. Ethers when fluorinated can serve as CFCs substitute. Therefore, in this work, an Insilco investigation was conducted on the thermochemistry, mechanism and kinetics of the Hydrogen abstraction reactions of partially fluorinated isopropyl methyl ether (1-fluoro-2-methoxypropane i.e. (CH2FCH(OCH3)CH3)) with Bromine monoxide radical (BrO.) using the Density Functional Theory (DFT) based M06-2X/6-311++G** strategy. To computationally refine/improve the energy data, the single-point calculations (DFT/M06-2X/6-311++G(2df,2p) were immediately executed on the reacting species involved. The Monte Carlo search on the investigating CH2FCH(OCH3)CH3 showed nine conformers with the lowest global minimum configuration being studied. The results of this investigation showed that the atmospheric oxidation reaction of CH2FCH(OCH3)CH3 with the BrO radical proceeded in four (4) plausible reaction routes. The computed total theoretical rate of 7.95*〖10〗^(-11) M-1 sec-1, the first of its kind with BrO radical was recorded. The atmospheric lifetime/global warming potential of 1.35*10-2 days/72.8 were also reported. The potential energy surface (PES) for each reaction route with the BrO radical was constructed at absolute temperature of 298.15 K.

Bromate is toxic compound which represent the carcinogenic effect for human health, a serial research’s has been developed by the scientists for the efficient bromate removal methods from the water with low cost in order to obtain water to Bromate a maximum concentration level (10ppb). Bromate ions are formed as a result of the reaction between bromide ions and ozone used as a water disinfectant in membrane demineralization plants .Different technologies have been used for Bromate elimination from water such as ion exchange, adsorption, biofiltration, electrolysis and membrane technology. The aim of this work is to study the rejection of bromate ions by nanofiltration membranes (N30F from Nadir and DL from Osmonics) made from different polymers using bromate solution at different conditions (feed bromate concentration, transmembrane pressure, pH and ionic strength).The bromate rejection is related to the feed solution, pH and ionic strength and the nature of the membrane. At pH=8, bromate ions were removed by the DL membrane made from polyamide around with higher than those by the N30F made from polyethersulfone

Article history:Received Received in revised form Accepted Available online In this research, a novel solid acid catalyst, sulfonic acid immobilized on poly ionic liquid (SPIL), was described. The final catalyst, SPIL, which was simply synthesized and characterized by fourier transform infrared spectroscopy and thermo‐gravimetric analysis, was found to be an efficient and environmentally benign solid acid for the Pechmann and esterification reactions under the solvent free conditions. The studies showed that the catalyst could be easily recovered and reused at least three reaction cycles without any significant loss in catalytic activity and efficiency. 1. Introduction Ionic liquids, a class of low-melting chemical compounds that include an organic cation and an organic/inorganic anion, are known as molten salts. Generally, the cation is an organic species containing heteroatoms such as phosphorous, sulfur, and nitrogen and the anion may be varied as chloride, bromide, iodide, tetrafluoroborate, hexafluorophosphate, nitrate, and acetate [1]. Because of their unique properties such as non-volatility, non-flammability, safety, recyclability and ability to dissolve a wide range of compounds, a variety of ionic liquids have been used in organic synthesis [2-6].In recent years, synthesis of

Convection flow is passed in a pipe wall possessing radiation-convection, in order to find the best case with at least enthalpy and minimum entropy generation, through pipe wall having radiant flow. Flow in developed laminar conditions is investigated. Radiant flow is simulated Passing the natural convection on the wall with for 6 cases. Variation of radiation along the pipe touching with natural convection causes to change temperature, entropy generation and enthalpy for each case. Different profiles are investigated distributions of temperature, entropy generation and enthalpy along the radius. Along the wall are shown variation in enthalpy and entropy generation. There have been increased in radiation-convection boundary conditions temperature, enthalpy as well as entropy generation. Along the radius and axis have appropriately been increased in radiation boundary conditions than convection, the amounts of enthalpy. Near the wall are occurred the most changes in temperature, enthalpy and entropy generation. Application the thermal boundary conditions are used for minimum entropy generation make fluid with high prandtl number to become high thermal carrier. Solar radiation application are used in Parabolic Trough, Parabolic Dish, Solar Chimney and tube furnace in various cases. Application are used for minimum entropy generation.

In this work, density functional theory (DFT) calculations at the M06-2X/6-31+G* level are performed to the adsorption of COn (n=1, 2) and HnX (n=2, 3 and X=O, N)molecules onto pristine as well as Al- and Ga-doped B12N12 nanocages. We study the effect of Al- and Ga-doped on the sensing properties of B12N12 nanocages. We investigated several doping and adsorption possibilities. This study illustrates the electrical behavior which has been gainded from the B12N12, Al- and Ga-doped B12N12 nanocages upon the COn (n=1, 2) and HnX (n=2, 3 and X=O, N) molecules adsorption. The structural stability was based on the minimum energy and non-complex vibrational frequencies. The results represents that large forces of attraction in B12N12-NH3, AlB11N12-NH3 and GaB11N12-NH3 complexes with values of -1.54, -2.32 and -2.34 eV are compared to mentioned other configurations. Calculations unfold that the Al-doping B12N12 can significantly imprive both the adsorption energy and electronic properties of nanocage to NH3. For all configurations, the geometry optimizations, adsorption energy, energy gaps, NBO charge transfer, dipole moments, are computed. The computed DOS elucidates that a strong orbital hybridization occur between CO2, CO, H2O, NH3, pristine, Al- and Ga-doped B12N12 nanocages in adsorption process. Finally, the Al-doped B12N12 is awaited to be a potential novel sensor for indicating the presence COn (n=1, 2) and HnX (n=2, 3 and X=O, N) molecules.