Amal H. Al-Bagawi, Samya Sh. Alenezi, Ragaa El Sheikh, Ghada M. ABDEL FATTAH, Ayman A. Gouda
ABSTRACT. A new, fast, sensitive, simple, and green dispersive liquid–liquid microextraction (DLLME)-based spectrophotometric method for the determination of valacyclovir HCl (VAL) in pure form and pharmaceutical formulations has been developed and validated. The developed method is based on the formation of a coloured product through the reaction of VAL and 1,2-naphthoquine-4-sulfonate (NQS) at pH = 9. The important experimental parameters affecting the extraction efficiency were investigated and optimized. The tiny organic droplets had a wavelength of l = 505 nm. At the optimum conditions, linearity ranged from 0.06 to 2.0 μg/mL, with a linear correlation coefficient of 0.9995. The limits of detection and quantification were 0.02, and 0.06 μg/mL, respectively. The enhancement factor was 36.87. Good recovery as accuracy (99.50%) and relative standard deviation (RSD) as precision were 1.20%, respectively. The developed DLLME method was successfully applied to the determination of VAL in pharmaceutical formulations, and the validity was assessed by applying the standard addition technique. The results obtained by the proposed method for the pure VAL and commercial tablets agreed well with those obtained by the official method. KEY WORDS: Valacyclovir HCl, Spectrophotometry, 1-2-Naphthoquine-4-sulfonate, Dispersive liquid–liquid microextraction, Pharmaceutical formulations Bull. Chem. Soc. Ethiop. 2023, 37(3), 579-592. DOI: https://dx.doi.org/10.4314/bcse.v37i3.4
{"title":"Development of an efficient dispersive liquid-liquid microextraction approach combined with spectrophotometry for determination of antiviral drug, valacyclovir HCl in pharmaceutical formulations","authors":"Amal H. Al-Bagawi, Samya Sh. Alenezi, Ragaa El Sheikh, Ghada M. ABDEL FATTAH, Ayman A. Gouda","doi":"10.4314/bcse.v37i3.4","DOIUrl":"https://doi.org/10.4314/bcse.v37i3.4","url":null,"abstract":"ABSTRACT. A new, fast, sensitive, simple, and green dispersive liquid–liquid microextraction (DLLME)-based spectrophotometric method for the determination of valacyclovir HCl (VAL) in pure form and pharmaceutical formulations has been developed and validated. The developed method is based on the formation of a coloured product through the reaction of VAL and 1,2-naphthoquine-4-sulfonate (NQS) at pH = 9. The important experimental parameters affecting the extraction efficiency were investigated and optimized. The tiny organic droplets had a wavelength of l = 505 nm. At the optimum conditions, linearity ranged from 0.06 to 2.0 μg/mL, with a linear correlation coefficient of 0.9995. The limits of detection and quantification were 0.02, and 0.06 μg/mL, respectively. The enhancement factor was 36.87. Good recovery as accuracy (99.50%) and relative standard deviation (RSD) as precision were 1.20%, respectively. The developed DLLME method was successfully applied to the determination of VAL in pharmaceutical formulations, and the validity was assessed by applying the standard addition technique. The results obtained by the proposed method for the pure VAL and commercial tablets agreed well with those obtained by the official method. \u0000 \u0000KEY WORDS: Valacyclovir HCl, Spectrophotometry, 1-2-Naphthoquine-4-sulfonate, Dispersive liquid–liquid microextraction, Pharmaceutical formulations \u0000 \u0000Bull. Chem. Soc. Ethiop. 2023, 37(3), 579-592. \u0000DOI: https://dx.doi.org/10.4314/bcse.v37i3.4","PeriodicalId":9501,"journal":{"name":"Bulletin of the Chemical Society of Ethiopia","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45974745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Raghad Haddad, S. Khadum, M. Ali, A. Majeed, A. Husain, Muna S. Bufaroosha, D. Ahmed, E. Yousif
ABSTRACT. Five organotin(IV) complexes including captopril (ligand) were employed in small amount as photostabilizers for poly(vinyl chloride) (PVC) when irradiated by UV light. Polymer’s samples were cast into films in order to conduct the UV exposure impact. The photodegradation rate constant (kd) of blank and organotin(IV) complexes embedded PVC specimens were investigated in this work. The kd values of filled samples were lower than the blank one, which indicates higher stability of these embedded films. Among these additives, triphenyltin(IV) showed the highest stability effect. KEY WORDS: PVC, Organotin(IV) complexes, Photostability, Photodegradation, UV light Bull. Chem. Soc. Ethiop. 2023, 37(3), 771-777. a DOI: https://dx.doi.org/10.4314/bcse.v37i3.18
摘要以卡托普利(配体)等5种有机锡(IV)配合物作为聚氯乙烯(PVC)的光稳定剂。聚合物样品被浇铸成薄膜，以进行紫外线曝光冲击。研究了空白和有机锡(IV)配合物包埋PVC样品的光降解速率常数(kd)。填充样品的kd值低于空白样品，表明这些包埋膜具有较高的稳定性。其中，三苯基锡(IV)的稳定效果最好。关键词:PVC，有机锡(IV)配合物，光稳定性，光降解，紫外光化学。Soc。阿比西尼亚人。2023年,37 (3),771 - 777 . a DOI: https://dx.doi.org/10.4314/bcse.v37i3.18
{"title":"Inorganic tin(IV) complexes as photo-stabilizer for PVC","authors":"Raghad Haddad, S. Khadum, M. Ali, A. Majeed, A. Husain, Muna S. Bufaroosha, D. Ahmed, E. Yousif","doi":"10.4314/bcse.v37i3.18","DOIUrl":"https://doi.org/10.4314/bcse.v37i3.18","url":null,"abstract":"ABSTRACT. Five organotin(IV) complexes including captopril (ligand) were employed in small amount as photostabilizers for poly(vinyl chloride) (PVC) when irradiated by UV light. Polymer’s samples were cast into films in order to conduct the UV exposure impact. The photodegradation rate constant (kd) of blank and organotin(IV) complexes embedded PVC specimens were investigated in this work. The kd values of filled samples were lower than the blank one, which indicates higher stability of these embedded films. Among these additives, triphenyltin(IV) showed the highest stability effect. \u0000 \u0000KEY WORDS: PVC, Organotin(IV) complexes, Photostability, Photodegradation, UV light \u0000 \u0000Bull. Chem. Soc. Ethiop. 2023, 37(3), 771-777. a \u0000DOI: https://dx.doi.org/10.4314/bcse.v37i3.18","PeriodicalId":9501,"journal":{"name":"Bulletin of the Chemical Society of Ethiopia","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42302598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Temitope E. Olalekan, Eric O. Akintemi, B. van Brecht, G. M. Watkins
ABSTRACT. Five new Schiff bases synthesized by the reaction between 2-(methylthio)aniline derivatives and p-methoxysalicylaldehyde are presented as MtH-1 (R = H), MtH-2 (R = CH3), MtH-3 (R = OCH3), MtH-4 (R = Cl) and MtH-5 (R = Br). They were characterized by CHNS analyses, NMR (1H, 13C, DEPT135, COSY and HSQC), FTIR and UV-Vis spectroscopic techniques. FT-IR, elemental analyses and NMR data supported the formation of the Schiff bases, with the chemical shifts of azomethine and phenol protons showing sensitivity to ring substitution. The crystal structure of MtH-1 featured the alignment of the phenyl rings to each other and to the C=N group with dihedral angles >170o. The DFT calculations corroborated the bond lengths and angles of MtH-1. The HOMO-LUMO energies, dipole moments and other reactivity parameters were calculated. The methyl-substituted MtH-2 was the least polar of the compounds. With calculated energy band gaps of almost 4 eV, the compounds may have applications in the semiconductors field. KEY WORDS: Schiff bases, p-methoxysalicylaldehyde, Crystal structure, Spectroscopic properties, DFT calculations Bull. Chem. Soc. Ethiop. 2023, 37(3), 675-688. DOI: https://dx.doi.org/10.4314/bcse.v37i3.11
{"title":"Synthesis, characterization and DFT studies of Schiff bases of p-methoxysalicylaldehyde","authors":"Temitope E. Olalekan, Eric O. Akintemi, B. van Brecht, G. M. Watkins","doi":"10.4314/bcse.v37i3.11","DOIUrl":"https://doi.org/10.4314/bcse.v37i3.11","url":null,"abstract":"ABSTRACT. Five new Schiff bases synthesized by the reaction between 2-(methylthio)aniline derivatives and p-methoxysalicylaldehyde are presented as MtH-1 (R = H), MtH-2 (R = CH3), MtH-3 (R = OCH3), MtH-4 (R = Cl) and MtH-5 (R = Br). They were characterized by CHNS analyses, NMR (1H, 13C, DEPT135, COSY and HSQC), FTIR and UV-Vis spectroscopic techniques. FT-IR, elemental analyses and NMR data supported the formation of the Schiff bases, with the chemical shifts of azomethine and phenol protons showing sensitivity to ring substitution. The crystal structure of MtH-1 featured the alignment of the phenyl rings to each other and to the C=N group with dihedral angles >170o. The DFT calculations corroborated the bond lengths and angles of MtH-1. The HOMO-LUMO energies, dipole moments and other reactivity parameters were calculated. The methyl-substituted MtH-2 was the least polar of the compounds. With calculated energy band gaps of almost 4 eV, the compounds may have applications in the semiconductors field. \u0000 \u0000KEY WORDS: Schiff bases, p-methoxysalicylaldehyde, Crystal structure, Spectroscopic properties, DFT calculations \u0000 \u0000Bull. Chem. Soc. Ethiop. 2023, 37(3), 675-688. \u0000DOI: https://dx.doi.org/10.4314/bcse.v37i3.11","PeriodicalId":9501,"journal":{"name":"Bulletin of the Chemical Society of Ethiopia","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41871778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT. The present study of biologically active Val-Trp dipeptide has been performed using computer modeling methods. To search the stable structures the different theoretically possible conformations of this molecule were calculated within molecular mechanics framework. The results showed that two types of conformations, folded and extended, are realized for this compound. Afterwards, the most stable conformations of the Val-Trp dipeptide were optimized using DFT/B3LYP level of theory with 6-31+G(d,p) basis set. The geometry, energy parameters, electronic properties, molecular electrostatic potential (MEP) map, highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies, chemical reactivity descriptors, nonlinear optical properties such as the electric dipole moment and polarizability were computed and compared for the optimized extended and folded structures of this molecule. The differences in the electronic structure between two characteristic conformations of title dipeptide were revealed. It was found the redistribution of charges as a result of folding of the peptide chain leads to a decrease in the dipole moment of this molecule. The effects of intramolecular hydrogen bonding on geometry of Val-Trp dipeptide were observed. KEY WORDS: Val-Trp dipeptide, Molecular Mechanics, DFT calculations Bull. Chem. Soc. Ethiop. 2023, 37(3), 757-770. DOI: https://dx.doi.org/10.4314/bcse.v37i3.17
{"title":"Structural analysis of Val-Trp dipeptide: Molecular mechanics and DFT calculations","authors":"Sara Gambar Rahimzade, Gulnara Ahmad Akverdieva","doi":"10.4314/bcse.v37i3.17","DOIUrl":"https://doi.org/10.4314/bcse.v37i3.17","url":null,"abstract":"ABSTRACT. The present study of biologically active Val-Trp dipeptide has been performed using computer modeling methods. To search the stable structures the different theoretically possible conformations of this molecule were calculated within molecular mechanics framework. The results showed that two types of conformations, folded and extended, are realized for this compound. Afterwards, the most stable conformations of the Val-Trp dipeptide were optimized using DFT/B3LYP level of theory with 6-31+G(d,p) basis set. The geometry, energy parameters, electronic properties, molecular electrostatic potential (MEP) map, highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies, chemical reactivity descriptors, nonlinear optical properties such as the electric dipole moment and polarizability were computed and compared for the optimized extended and folded structures of this molecule. The differences in the electronic structure between two characteristic conformations of title dipeptide were revealed. It was found the redistribution of charges as a result of folding of the peptide chain leads to a decrease in the dipole moment of this molecule. The effects of intramolecular hydrogen bonding on geometry of Val-Trp dipeptide were observed. \u0000 \u0000KEY WORDS: Val-Trp dipeptide, Molecular Mechanics, DFT calculations \u0000 \u0000Bull. Chem. Soc. Ethiop. 2023, 37(3), 757-770. \u0000DOI: https://dx.doi.org/10.4314/bcse.v37i3.17","PeriodicalId":9501,"journal":{"name":"Bulletin of the Chemical Society of Ethiopia","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42702384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. M. Mohareb, Maher H.E. Helal, Amany E. Mayhoub, Amira E.M. Abdallah
ABSTRACT. A new approaches for the synthesis of novel pyrazolo[1,5-a]quinazoline 8a-f and pyrazolo[1,5-a]quinazolin-6-one 10a-s and 12a-s derivatives were obtained using 4-(2-phenylhydrazono)-4H-pyrazol-3-amine derivatives 5a-f via their multi-component reactions. The later pyrazole derivatives were prepared via arylhydrazone derivatives 3a-f. The structures of the synthesized compounds were established based on their respective analytical data. On the other hand, the cytotoxic effects of the synthesized compounds were obtained against the six cancer cell lines, namely A549, HT-29, MKN-45, U87MG, SMMC-7721 and, H460 utilizing foretinib as the positive control and the standard MTT assay in vitro. The obtained results showed that compounds 8c, 8f, 10c, 10i, 10l, 10p, 10s, 12c, 12i, 12l, 12p and, 12s were the most cytotoxic compounds. In most cases the presence of the electronegative Cl group enhanced the cytotoxicity of the tested compound. KEY WORDS: Multi-component reactions, Pyrazolo[1,5-a]quinazoline, Pyrazolo[1,5-a]quinazolin-6-one, Cytotoxicity Bull. Chem. Soc. Ethiop. 2023, 37(3), 717-734. DOI: https://dx.doi.org/10.4314/bcse.v37i3.14
{"title":"Multi-component reactions for the synthesis of pyrazolo [1,5-a]quinoline derivatives together with their cytotoxic evaluations","authors":"R. M. Mohareb, Maher H.E. Helal, Amany E. Mayhoub, Amira E.M. Abdallah","doi":"10.4314/bcse.v37i3.14","DOIUrl":"https://doi.org/10.4314/bcse.v37i3.14","url":null,"abstract":"ABSTRACT. A new approaches for the synthesis of novel pyrazolo[1,5-a]quinazoline 8a-f and pyrazolo[1,5-a]quinazolin-6-one 10a-s and 12a-s derivatives were obtained using 4-(2-phenylhydrazono)-4H-pyrazol-3-amine derivatives 5a-f via their multi-component reactions. The later pyrazole derivatives were prepared via arylhydrazone derivatives 3a-f. The structures of the synthesized compounds were established based on their respective analytical data. On the other hand, the cytotoxic effects of the synthesized compounds were obtained against the six cancer cell lines, namely A549, HT-29, MKN-45, U87MG, SMMC-7721 and, H460 utilizing foretinib as the positive control and the standard MTT assay in vitro. The obtained results showed that compounds 8c, 8f, 10c, 10i, 10l, 10p, 10s, 12c, 12i, 12l, 12p and, 12s were the most cytotoxic compounds. In most cases the presence of the electronegative Cl group enhanced the cytotoxicity of the tested compound. \u0000 \u0000KEY WORDS: Multi-component reactions, Pyrazolo[1,5-a]quinazoline, Pyrazolo[1,5-a]quinazolin-6-one, Cytotoxicity \u0000Bull. Chem. Soc. Ethiop. 2023, 37(3), 717-734. \u0000DOI: https://dx.doi.org/10.4314/bcse.v37i3.14","PeriodicalId":9501,"journal":{"name":"Bulletin of the Chemical Society of Ethiopia","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41866626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT. Vernonia oil is a naturally epoxidized triglyceride oil extracted from the seed of Vernonia galamensis, a native plant in East Africa. After hydrolysis to vernolic acid (VA) and derivatization, vernolic acid methyl ester (VAME) is synthesized and used to functionalize ordered mesoporous materials (OMM). Al-MCM-41 with Si/Al ratio of 15, pure silica SBA-15 and periodic mesoporous organosilica (PMO) are employed as supports exploring the different surface properties. Following optimization of the VAME/OMM ratios, selected samples, i.e. those with 13% VAME, were impregnated with AgNO3 in NaBH4 to obtain Ag-nanoparticles. The final AgVAME-OMM potential catalysts were characterized by transmission electron microscopy, observing an efficient loading of Ag nanoparticles in pure silica SBA-15 with VAME with 500 m2 specific surface area and 6 nm pore size. KEY WORDS: Vernolic acid methyl ester, Vernonia oil, Functionalization, Ordered mesoporous materials, Catalysis Bull. Chem. Soc. Ethiop. 2023, 37(3), 689-702. DOI: https://dx.doi.org/10.4314/bcse.v37i3.12
{"title":"Preparation and characterization of vernolic acid methyl ester functionalized ordered mesoporous materials","authors":"Y. Chebude, G. Gonfa, I. Díaz","doi":"10.4314/bcse.v37i3.12","DOIUrl":"https://doi.org/10.4314/bcse.v37i3.12","url":null,"abstract":"ABSTRACT. Vernonia oil is a naturally epoxidized triglyceride oil extracted from the seed of Vernonia galamensis, a native plant in East Africa. After hydrolysis to vernolic acid (VA) and derivatization, vernolic acid methyl ester (VAME) is synthesized and used to functionalize ordered mesoporous materials (OMM). Al-MCM-41 with Si/Al ratio of 15, pure silica SBA-15 and periodic mesoporous organosilica (PMO) are employed as supports exploring the different surface properties. Following optimization of the VAME/OMM ratios, selected samples, i.e. those with 13% VAME, were impregnated with AgNO3 in NaBH4 to obtain Ag-nanoparticles. The final AgVAME-OMM potential catalysts were characterized by transmission electron microscopy, observing an efficient loading of Ag nanoparticles in pure silica SBA-15 with VAME with 500 m2 specific surface area and 6 nm pore size. \u0000 \u0000KEY WORDS: Vernolic acid methyl ester, Vernonia oil, Functionalization, Ordered mesoporous materials, Catalysis \u0000 \u0000Bull. Chem. Soc. Ethiop. 2023, 37(3), 689-702. \u0000DOI: https://dx.doi.org/10.4314/bcse.v37i3.12","PeriodicalId":9501,"journal":{"name":"Bulletin of the Chemical Society of Ethiopia","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46132359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. S. Refat, M. Y. El-Sayed, Ibrahim H. Alsohaimi, Hassan M. Hassan, Thamer S. Alraddadid, Sultan Akhtar
ABSTRACT. Nickel(II) and cadmium(II) sulfides are a promising chemical material in various advanced research areas such as solar cells, supercapacitors, catalysts, and of significant interest for their practical implementations in up to photonics and electronics. Cadmium and nickel sulfides were synthesized with stoichiometries in aqueous media at elevated temperature from Ni(NO3)2.6H2O, NiCl2.6H2O, NiSO4.6H2O, CdCl2, Cd(NO3)2.4H2O, CdSO4.8H2O and thiourea as a sulfur precursor using a direct chemical reaction. At room temperature an octahedral and tetrahedral geometries result from the reactions between different nickel(II), cadmium(II) and thiourea with the molecular formulas can be presented as [Ni(NH2CSNH2)6]X2 and [Cd(NH2CSNH2)4]X2 where X = Cl-, NO3-, SO42. The novelty of our study is precipitated yellow cadmium sulfide and black nickel sulfide at elevated temperature ~80 oC through the molar ratio 1:10 (M2+: thiourea) in aqueous media. Infrared spectra, XRD, TEM including EDX, and elemental analysis were used for characterization the metal sulfides products. The average crystalline size of obtained CdS and NiS particles in range 20-25 nm. Different reaction conditions effects were evaluated on the size, morphology and particle size. KEY WORDS: Nickel and cadmium sulfide, Chelation, Thiourea, XRD, TEM Bull. Chem. Soc. Ethiop. 2023, 37(3), 663-674. DOI: https://dx.doi.org/10.4314/bcse.v37i3.10
{"title":"A simple and low-cost new procedure for synthesis of nickel(II) and cadmium(II) sulfides in situ thiourea metal–chelation precursor","authors":"M. S. Refat, M. Y. El-Sayed, Ibrahim H. Alsohaimi, Hassan M. Hassan, Thamer S. Alraddadid, Sultan Akhtar","doi":"10.4314/bcse.v37i3.10","DOIUrl":"https://doi.org/10.4314/bcse.v37i3.10","url":null,"abstract":"ABSTRACT. Nickel(II) and cadmium(II) sulfides are a promising chemical material in various advanced research areas such as solar cells, supercapacitors, catalysts, and of significant interest for their practical implementations in up to photonics and electronics. Cadmium and nickel sulfides were synthesized with stoichiometries in aqueous media at elevated temperature from Ni(NO3)2.6H2O, NiCl2.6H2O, NiSO4.6H2O, CdCl2, Cd(NO3)2.4H2O, CdSO4.8H2O and thiourea as a sulfur precursor using a direct chemical reaction. At room temperature an octahedral and tetrahedral geometries result from the reactions between different nickel(II), cadmium(II) and thiourea with the molecular formulas can be presented as [Ni(NH2CSNH2)6]X2 and [Cd(NH2CSNH2)4]X2 where X = Cl-, NO3-, SO42. The novelty of our study is precipitated yellow cadmium sulfide and black nickel sulfide at elevated temperature ~80 oC through the molar ratio 1:10 (M2+: thiourea) in aqueous media. Infrared spectra, XRD, TEM including EDX, and elemental analysis were used for characterization the metal sulfides products. The average crystalline size of obtained CdS and NiS particles in range 20-25 nm. Different reaction conditions effects were evaluated on the size, morphology and particle size. \u0000 \u0000KEY WORDS: Nickel and cadmium sulfide, Chelation, Thiourea, XRD, TEM \u0000Bull. Chem. Soc. Ethiop. 2023, 37(3), 663-674. \u0000DOI: https://dx.doi.org/10.4314/bcse.v37i3.10 \u0000 ","PeriodicalId":9501,"journal":{"name":"Bulletin of the Chemical Society of Ethiopia","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49422882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sıla Sadiye Ilhan, F. Demir, Omer Lacin, Fatih Sevim
ABSTRACT. The solubility of low-grade zinc ores with a selective leaching environmentally friendly reagent has become a focus of great interest since zinc and its compounds have found wide application. For this purpose, lactic acid was used to investigate the selective leaching kinetics of smithsonite ore obtained from Kayseri region. The effects of particle size (137.5-725 µm), acid concentration (0.5-5 M), solid/liquid ratio (0.5/250-3/250 g mL-1), stirring speed (500-800 rpm) and temperature (40-70 °C) parameters on the smithsonite dissolution rate were experimentally studied. The results obtained show that leaching of about 99.8% of zinc is achieved using 425 µm particle size at a reaction temperature of 70 °C for 45 min reaction time with 2 M lactic acid, the solid/liquid ratio of 1/250 g mL-1 and stirring speed of 600 rpm. The statistical analysis of the experimental data obtained from the parameters revealed that smithsonite dissolution was the surface reaction-controlled with an apparent activation energy of 53.62 kJ.moL-1. The kinetic model describing the process was found as KEY WORDS: Smithsonite, Dissolution kinetics, Lactic acid, Zinc lactate Bull. Chem. Soc. Ethiop. 2023, 37(3), 735-744. DOI: https://dx.doi.org/10.4314/bcse.v37i3.15
{"title":"Zinc leaching from smithsonite ore in lactic acid solution: Studies on parametric optimization, kinetic and mechanism","authors":"Sıla Sadiye Ilhan, F. Demir, Omer Lacin, Fatih Sevim","doi":"10.4314/bcse.v37i3.15","DOIUrl":"https://doi.org/10.4314/bcse.v37i3.15","url":null,"abstract":"ABSTRACT. The solubility of low-grade zinc ores with a selective leaching environmentally friendly reagent has become a focus of great interest since zinc and its compounds have found wide application. For this purpose, lactic acid was used to investigate the selective leaching kinetics of smithsonite ore obtained from Kayseri region. The effects of particle size (137.5-725 µm), acid concentration (0.5-5 M), solid/liquid ratio (0.5/250-3/250 g mL-1), stirring speed (500-800 rpm) and temperature (40-70 °C) parameters on the smithsonite dissolution rate were experimentally studied. The results obtained show that leaching of about 99.8% of zinc is achieved using 425 µm particle size at a reaction temperature of 70 °C for 45 min reaction time with 2 M lactic acid, the solid/liquid ratio of 1/250 g mL-1 and stirring speed of 600 rpm. The statistical analysis of the experimental data obtained from the parameters revealed that smithsonite dissolution was the surface reaction-controlled with an apparent activation energy of 53.62 kJ.moL-1. The kinetic model describing the process was found as \u0000 \u0000KEY WORDS: Smithsonite, Dissolution kinetics, Lactic acid, Zinc lactate \u0000Bull. Chem. Soc. Ethiop. 2023, 37(3), 735-744. \u0000DOI: https://dx.doi.org/10.4314/bcse.v37i3.15","PeriodicalId":9501,"journal":{"name":"Bulletin of the Chemical Society of Ethiopia","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46169807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT. In this study, physicochemical properties and microbial loads of raw and sterilized cow milks of Jimma town, Ethiopia, were investigated. Raw and sterilized milk samples were collected from milk venders and local market, respectively. Standard methods were used for analysis of both physicochemical and microbial loads of the samples. The results of the study showed that physicochemical properties of the studied milk samples were within the recommended values. The total bacteria count (TBC) and coliform count (CC) of raw milk samples were above the recommended values, whereas their values in the sterilized milk sample were comparable with the recommended values. However, the yeast and mould count (YMC) of the studied milk samples were comparable with their recommended values. ANOVA (p < 0.05) results showed the presence of significant differences in the physicochemical properties such as temperature, pH, titratable acidity, total solids, solids not fat, protein, fat, lactose, total bacteria count and coliform count among the studied milk samples. In general, the studied raw and sterilized milk samples had acceptable physicochemical properties. However, the TBC and CC of the raw milk samples were above their respective recommended values, which might be attributed to the low hygienic practices of the venders. KEYWORDS: Raw and sterilized cow milks, Physicochemical properties, Microbial load Bull. Chem. Soc. Ethiop. 2023, 37(3), 553-563. DOI: https://dx.doi.org/10.4314/bcse.v37i3.2
{"title":"Physicochemical properties and microbial load evaluation of raw cow milks of Jimma Town, Ethiopia","authors":"Tesfaye Tadesse, A. Gure, K. Kedir","doi":"10.4314/bcse.v37i3.2","DOIUrl":"https://doi.org/10.4314/bcse.v37i3.2","url":null,"abstract":"ABSTRACT. In this study, physicochemical properties and microbial loads of raw and sterilized cow milks of Jimma town, Ethiopia, were investigated. Raw and sterilized milk samples were collected from milk venders and local market, respectively. Standard methods were used for analysis of both physicochemical and microbial loads of the samples. The results of the study showed that physicochemical properties of the studied milk samples were within the recommended values. The total bacteria count (TBC) and coliform count (CC) of raw milk samples were above the recommended values, whereas their values in the sterilized milk sample were comparable with the recommended values. However, the yeast and mould count (YMC) of the studied milk samples were comparable with their recommended values. ANOVA (p < 0.05) results showed the presence of significant differences in the physicochemical properties such as temperature, pH, titratable acidity, total solids, solids not fat, protein, fat, lactose, total bacteria count and coliform count among the studied milk samples. In general, the studied raw and sterilized milk samples had acceptable physicochemical properties. However, the TBC and CC of the raw milk samples were above their respective recommended values, which might be attributed to the low hygienic practices of the venders. \u0000 \u0000KEYWORDS: Raw and sterilized cow milks, Physicochemical properties, Microbial load \u0000 \u0000Bull. Chem. Soc. Ethiop. 2023, 37(3), 553-563. \u0000DOI: https://dx.doi.org/10.4314/bcse.v37i3.2","PeriodicalId":9501,"journal":{"name":"Bulletin of the Chemical Society of Ethiopia","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44123975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT. The effect of acetic acid and ethanol as polar aqueous solvents on sulfuric acid with hydrogen peroxide as an oxidant was studied. A small amount of these polar aqueous solvents significantly improved the copper leaching recovery. The leaching parameters such as temperature, stirring speed, H2O2 concentration, solid/liquid ratio, H2SO4 concentration and particle size were examined. About 76.33% as highest Cu extraction was gained with 2 M H2O2, 600 rpm stirring speed, 50 °C temperature, 1 M H2SO4, 240 min of the reaction and 75 x 53 µm particle size fraction. Further experimental tests were carried out when the stirring speed, solid-to-liquid ratio (S/L), particle size, H2O2 concentration, temperature and H2SO4 concentration were kept constant to investigate the effect of ethanol and acetic acid concentration in the range of 0–2 M. The experimental results proved that the copper extraction recovery reached to 99.03% in 180 min of the reaction with 2 M acetic acid. While 2 M of ethanol increased copper extraction recovery up to 100% in 90 min of the leaching time. The dissolution reaction found to be described by mixed kinetic model and activation energy of 54.37 kJ/mol. Addition of acetic acid and ethanol suggested reaction controlled by diffusion across product layer. KEY WORDS: Hydrogen peroxide, Sulfuric acid, Activation energy, Leaching, Chalcopyrite Bull. Chem. Soc. Ethiop. 2023, 37(3), 779-788. DOI: https://dx.doi.org/10.4314/bcse.v37i3.19
摘要。研究了乙酸和乙醇作为极性水性溶剂对过氧化氢氧化硫酸的影响。少量的这些极性水性溶剂显著提高了铜的浸出回收率。考察了温度、搅拌速度、H2O2浓度、固液比、H2SO4浓度和粒度等浸出参数。在2 M H2O2、600 rpm搅拌速度、50°C温度、1 M H2SO4、240分钟反应和75 x 53µM粒径分数的条件下，获得了约76.33%的最高铜提取率。当搅拌速度、固液比（S/L）、粒度、H2O2浓度、温度和H2SO4浓度保持不变时，进行了进一步的实验测试，以研究乙醇和乙酸浓度在0–2M范围内的影响。实验结果表明，与2M乙酸反应180分钟，铜萃取回收率达到99.03%。而2M的乙醇在90分钟的浸出时间内将铜提取回收率提高到100%。溶解反应用混合动力学模型描述，活化能为54.37kJ/mol。乙酸和乙醇的加入表明反应通过产物层的扩散来控制。关键词：过氧化氢，硫酸，活化能，浸出，黄铜矿。化学。Soc.Ethiop。2023，37（3），779-788。DOI：https://dx.doi.org/10.4314/bcse.v37i3.19
{"title":"Investigation of the effect of some polar organic solvents on the leaching and dissolution kinetics of chalcopyrite in hydrogen peroxide and sulfuric acid solution","authors":"Mohamed Taha Osman Abdelraheem, T. Agacayak","doi":"10.4314/bcse.v37i3.19","DOIUrl":"https://doi.org/10.4314/bcse.v37i3.19","url":null,"abstract":"ABSTRACT. The effect of acetic acid and ethanol as polar aqueous solvents on sulfuric acid with hydrogen peroxide as an oxidant was studied. A small amount of these polar aqueous solvents significantly improved the copper leaching recovery. The leaching parameters such as temperature, stirring speed, H2O2 concentration, solid/liquid ratio, H2SO4 concentration and particle size were examined. About 76.33% as highest Cu extraction was gained with 2 M H2O2, 600 rpm stirring speed, 50 °C temperature, 1 M H2SO4, 240 min of the reaction and 75 x 53 µm particle size fraction. Further experimental tests were carried out when the stirring speed, solid-to-liquid ratio (S/L), particle size, H2O2 concentration, temperature and H2SO4 concentration were kept constant to investigate the effect of ethanol and acetic acid concentration in the range of 0–2 M. The experimental results proved that the copper extraction recovery reached to 99.03% in 180 min of the reaction with 2 M acetic acid. While 2 M of ethanol increased copper extraction recovery up to 100% in 90 min of the leaching time. The dissolution reaction found to be described by mixed kinetic model and activation energy of 54.37 kJ/mol. Addition of acetic acid and ethanol suggested reaction controlled by diffusion across product layer. \u0000 \u0000KEY WORDS: Hydrogen peroxide, Sulfuric acid, Activation energy, Leaching, Chalcopyrite \u0000 \u0000Bull. Chem. Soc. Ethiop. 2023, 37(3), 779-788. \u0000DOI: https://dx.doi.org/10.4314/bcse.v37i3.19","PeriodicalId":9501,"journal":{"name":"Bulletin of the Chemical Society of Ethiopia","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47390328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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