@article { author = {Salimi, Farahnaz and Karbakhshzade, Ayda and Salehi, Navid}, title = {A Review on Recent Approaches to the Asymmetric Synthesis of Aziridines Derivatives}, journal = {Journal of Chemistry Letters}, volume = {2}, number = {2}, pages = {56-63}, year = {2021}, publisher = {Eurasian Science Society (ESS)}, issn = {2821-0123}, eissn = {2717-1892}, doi = {10.22034/jchemlett.2021.301693.1037}, abstract = {The aziridines are an important class of heterocyclic compounds that are used for the synthesis of high valuable compounds containing biological and natural products. This review summarizes the recent advances in asymmetric synthesis of aziridines derivatives employing different strategies under different conditions.aziridines are saturated three-membered ring compounds containing a nitrogen and two carbon atoms}, keywords = {Synthesis of Aziridines,Asymmetric synthesis,Aziridination,Organic synthesis}, url = {https://www.jchemlett.com/article_136106.html}, eprint = {https://www.jchemlett.com/article_136106_e01b790e482d547b64b539bd63b01c10.pdf} } @article { author = {Norouzi, Nima}, title = {Future of Hydrogen in Energy Transition and Reform}, journal = {Journal of Chemistry Letters}, volume = {2}, number = {2}, pages = {64-72}, year = {2021}, publisher = {Eurasian Science Society (ESS)}, issn = {2821-0123}, eissn = {2717-1892}, doi = {10.22034/jchemlett.2021.301002.1036}, abstract = {In order to ensure energy supply and cope with climate change, a new round of energy transformation must be carried out. Hydrogen can play an important role in energy transformation with its high energy density and clean and low-carbon energy attributes. First of all, it clarified the development position of hydrogen energy in the transformation of energy. It pointed out that hydrogen energy is an energy carrier that promotes the large-scale development and utilization of renewable energy, and it is an energy medium that realizes the interconnection, complementation, and coordinated optimization of multiple energy networks. Secondly, the technical route for the development of the hydrogen energy industry is analyzed. Combining with the characteristics of China’s energy structure and development status, the development of the hydrogen energy industry should focus on the core advantages of clean, low-carbon, flexible and efficient, in the coordinated development of hydrogen and renewable energy, the clean production of industrial hydrogen, and the development of fuel cell technology. In addition, transportation power systems and distributed energy systems can give priority to promoting large-scale development.}, keywords = {Hydrogen energy,Renewable Energy,Carbon Emission,Energy Storage,Fuel Cell}, url = {https://www.jchemlett.com/article_135697.html}, eprint = {https://www.jchemlett.com/article_135697_3eea793a62f557dcdec932ed5a532065.pdf} } @article { author = {Maiki, Ernest}, title = {Experimental and theoretical investigation on low salinity brine injection timing in high water cut reservoirs for residual oil reduction and improved oil recovery}, journal = {Journal of Chemistry Letters}, volume = {2}, number = {2}, pages = {73-81}, year = {2021}, publisher = {Eurasian Science Society (ESS)}, issn = {2821-0123}, eissn = {2717-1892}, doi = {10.22034/jchemlett.2021.319588.1042}, abstract = {In this research, low salinity water flooding was used to investigate its low salinity effect in a high water cut sandstone reservoir to improve oil recovery. The application was done to five different sandstone cores in high water cut levels of 70%, 75%, 80%, 85% and 90% by injecting low salinity brines of 2000mg/L – 20,000mg/L NaCl concentrations. These Cores chosen for research had 27%-28% porosity and 280mD – 300 mD permeability. Different brine injection rates were considered from 0.5cm3/s to 3cm3/s in each experiment. The results showed that low salinity flooding can be used to harness more oil from high water cut reservoirs. However, water should be injected earlier to avoid porous particle dislodge by continuous flooding. Brines of 200mg/L-5,000mg/L NaCl yielded the highest Oil recovery compared to higher salinities of 10,000mg/L-20,000mg/L. This was partly due to increased jamin effect created as fluids flow at high water cut levels. Three water cut rising model levels were discussed for better timing to avoid porous particle detachment from the sandstone matrix. Early injection timing was discussed to be critical for low salinity injection to avoid the mentioned Particles phenomena and hence high water cut levels and low oil recovery.}, keywords = {low salinity flooding. High water cut,Sandstone,Residual oil saturation,Fines migration}, url = {https://www.jchemlett.com/article_142430.html}, eprint = {https://www.jchemlett.com/article_142430_745226899f4005fec7c96c3639daff3c.pdf} } @article { author = {Asadi, Zahra and Abdi, Hadi and Naji, Mehrdad and Rajabi, Hadi and Aminzadeh, Omid and Madadi, Kazem}, title = {Flocculation process and Increasing sedimentation of total suspended solids in clarifier}, journal = {Journal of Chemistry Letters}, volume = {2}, number = {2}, pages = {82-86}, year = {2021}, publisher = {Eurasian Science Society (ESS)}, issn = {2821-0123}, eissn = {2717-1892}, doi = {10.22034/jchemlett.2021.316716.1040}, abstract = {Sedimentation is the process of allowing particles in suspension in water to settle out of the suspension under the effect of gravity. The particles that settle out from the suspension become sediment, and in water treatment is known as sludge. Several factors can affect the sedimentation process including physical and environmental conditions. Increased pretreatment may be necessary when adverse conditions are present. Factors that affect the sedimentation process include the shape and size of particles, the density of particles, water temperature, Alkalinity of water, particle charge, dissolved substances in the water, environmental effects, and characteristics of the basin. Flocculation is the slow mixing process that causes smaller particles to merge into larger particles that settle more easily. Polymer flocculants are used to promote solid-liquid separation processes in potable water and wastewater treatment by controlling the rate of impacts between particles as they gain size. In this paper, the effect of increasing substance A23 to B90 polymer flocculant on the deposition of suspended solids is investigated. The results showed that by adding A23, the amount of particle sedimentation increases and water turbidity decreases, in addition by adding substance A23 to the polymeric flocculant, less amount of B90 flocculant polymer is required to increase the sedimentation efficiency.}, keywords = {Sedimentation,Total Suspended Solids (TSS),clarifier,Wastewater Treatment,saving water in industry}, url = {https://www.jchemlett.com/article_141368.html}, eprint = {https://www.jchemlett.com/article_141368_9e2e0df5dde1f6fa6a4f369599f592d0.pdf} } @article { author = {Iorhemen, Raymond and Adawara, Samuel and Gulanda, Gambo}, title = {Phytochemical Screening and Antibacterial Activity of the Ethanolic Stem Bark Extract of Eucalyptus Camaldulensis}, journal = {Journal of Chemistry Letters}, volume = {2}, number = {2}, pages = {89-95}, year = {2021}, publisher = {Eurasian Science Society (ESS)}, issn = {2821-0123}, eissn = {2717-1892}, doi = {10.22034/jchemlett.2021.308911.1039}, abstract = {In this study, the stem bark of Eucalyptus camaldulensis was subjected to preliminary phytochemical and anti-bacterial analysis. The extraction of the stem bark was done with ethanol with a recovery of 12.1 %. The phytochemical evaluation, as well as the antibacterial analysis of the ethanolic leaf extract, was carried out. The phytochemical analysis showed the presence of carbohydrates, terpineol, cardiac glycoside, flavonoids, tannin, and corderoites. The antibacterial analysis of the ethanolic extract showed activity on Staphylococcus aureus, Streptococcus pyrogens, E-coli, and Pseudomonas aeruginosa at different concentrations. Eucalyptus camaldulensis possesses medicinal value owing to the presence of important phytochemicals as well as inhibitory potential against some selected microbes. Also, Eucalyptus camaldulensis could be exploited in the treatment of diseases related to the investigated microbes.}, keywords = {medicinal plants,Solvent extraction,Antimicrobial activity,River Red Gum,herbal remedy}, url = {https://www.jchemlett.com/article_142174.html}, eprint = {https://www.jchemlett.com/article_142174_6b7bebd5ed14e595e1f1c20f980240d4.pdf} } @article { author = {akan, Joseph}, title = {Levels and Health Risk Assessment of Heavy Metal Contamination in Soil and Different Varieties of Rice from Jere Agricultural Locations, Borno State, North Eastern Nigeria}, journal = {Journal of Chemistry Letters}, volume = {2}, number = {2}, pages = {96-113}, year = {2021}, publisher = {Eurasian Science Society (ESS)}, issn = {2821-0123}, eissn = {2717-1892}, doi = {10.22034/jchemlett.2021.303893.1038}, abstract = {The present study was conducted to evaluate the levels, ecological and health risk of some heavy metals which include Hg, As, Pb, Cd, Ni and Cr from agricultural soils in Maiduguri Metropolis agricultural Location, North East Nigeria. The levels of the studied heavy metals were determine using Atomic Absorption Spectroscopy (AAS). The concentrations of the studied metals in the soil samples were significantly higher at a depth of 0-5 cm, while 10-15 cm showed the lowest. The concentrations of all the metal in the soil from both locations were relatively lower than the WHO/FAO permissible limits, while that of rice were all above the said WHO/FAO limits. Results from potential ecological risks assessment and potential ecological risk index (RI) indicate low ecological risk, except Cd. Also, AEI results for all the metals were greater than 1, indicating a possibility of likelihood to induce adverse biological effects to benthic organism with exception to Hg and Cd. The geo-accumulation index, contamination factor and pollution load index were observed to be low contamination and polluted for all the heavy metal except for Pb (Igeo) and Hg (CF). The soil ADD values for children and adult via ingestion and dermal contact were lower than their individual RfDs, which shows no threat from non-carcinogenic risk as a result of metal contamination. Inhalation routs for children and adult were higher than the RfDs values, indicating human health risk. The HQ and HI via ingestion and dermal pathways were lower than the threshold values, with exception of HQ and HI inhalation for both locations were much greater than 1, an indication of high potential non-cancer related illness. For all the varieties of rice, the HQ and HI values for all the metals were less than the US EPA permissible safety limit of 1, and therefore does not pose any serious health risk concern, except As which is greater than one (1), indicating high potential non-cancer health risk via consumption of rice. Carcinogenic health risk values of As, Pb and As in the soil via inhalation pathway for children and adult with ranged of 2.23E-03 to 8.10E-01 were higher than the said regulatory acceptable values of 1.0 x 10-6 to 1.0 x 10-4 showing possibility of inducing cancer risk, though CRing and CRdermal contact values for children and adult were within safety limits. Also, the potential health risk for children via the exposure pathways was greater than for adults, with exception of inhalation. Hence, the main exposure pathway of heavy metals for both children and adults is inhalation, followed by ingestion and dermal contact. Findings from this study suggest that values of some metals were high enough to cause health risk to human. The study further recommends regular monitoring of heavy metal in the soil and varieties of rice within the study locations in other to protect human health.}, keywords = {heavy metals,Soil,rice,Potential Ecological Risk Index,Health risk assessment}, url = {https://www.jchemlett.com/article_141367.html}, eprint = {https://www.jchemlett.com/article_141367_3f4e1696552033def49ef3add09e8d60.pdf} }