The protonation constants of the free ligands and the stability constants of binary and ternary complexes of bivalent metal ions of Ni(II) and Cu(II) with a biologically important amino acid of L-valine, Val, and paracetamol, Para, were studied potentiometrically in aqueous solutions at 313.15 ± 0.1 K and a fixed ionic strength of I = 0.10 M NaCl. The complexation model for each system was established using the Irving-Rossotti equation. The formation of the 1:2 or 1:1 binary complexes and 1:1:1 ternary complexes in which the amino acid Val was used as the primary ligand and Para as the secondary ligand, as inferred from the corresponding potentiometric pH-metric titration curves, and their relative stabilities compared to the corresponding ML and ML2 binary complexes are expressed in terms of statistical parameters ∆logK, logK1 and logK2. The complex stability was found to follow the order of Cu(II) > Ni(II). Through these diagnostic studies, it was possible to give the general formula of compounds prepared from amino acids and paracetamol. Amino acid binds to the central ion through oxygen in the hydroxyl group and nitrogen atom in the amine group (-NH2), whereas paracetamol forms a unipolar bond by binding to the concentrated ion through the oxygen atom in the hydroxyl group. Most of the nickel complexes had octahedral symmetry with valine and paracetamol ligands, while the copper complexes had square or hierarchical to square base symmetry.
在313.15±0.1 K、固定离子强度I = 0.10 M NaCl条件下，用电位法研究了自由配体的质子化常数以及Ni(II)和Cu(II)二价金属离子与l -缬氨酸Val和对乙酰氨基酚Para的二元和三元配合物的稳定性常数。利用Irving-Rossotti方程建立了各体系的络合模型。根据相应的电位滴定曲线，以氨基酸Val为一级配体，以Para为二级配体的1:2或1:1二元配合物和1:1:1三元配合物的形成，与相应的ML和ML2二元配合物相比，它们的相对稳定性用统计参数∆logK, logK1和logK2表示。络合物的稳定性依次为Cu(II) > Ni(II)。通过这些诊断研究，有可能给出由氨基酸和扑热息痛制备的化合物的一般配方。氨基酸通过羟基上的氧和胺基上的氮原子(-NH2)与中心离子结合，而扑热息痛通过羟基上的氧原子与浓离子结合形成单极键。大多数镍配合物与缬氨酸和扑热息痛配体呈八面体对称，而铜配合物呈正方形或分层到正方形的基对称。
{"title":"Potentiometric Studies on Binary and Ternary Complexes of Ni(II) and Cu(II) Ions with L-Valine and Paracetamol","authors":"","doi":"10.18596/jotcsa.1140039","DOIUrl":"https://doi.org/10.18596/jotcsa.1140039","url":null,"abstract":"The protonation constants of the free ligands and the stability constants of binary and ternary complexes of bivalent metal ions of Ni(II) and Cu(II) with a biologically important amino acid of L-valine, Val, and paracetamol, Para, were studied potentiometrically in aqueous solutions at 313.15 ± 0.1 K and a fixed ionic strength of I = 0.10 M NaCl. The complexation model for each system was established using the Irving-Rossotti equation. The formation of the 1:2 or 1:1 binary complexes and 1:1:1 ternary complexes in which the amino acid Val was used as the primary ligand and Para as the secondary ligand, as inferred from the corresponding potentiometric pH-metric titration curves, and their relative stabilities compared to the corresponding ML and ML2 binary complexes are expressed in terms of statistical parameters ∆logK, logK1 and logK2. The complex stability was found to follow the order of Cu(II) > Ni(II). Through these diagnostic studies, it was possible to give the general formula of compounds prepared from amino acids and paracetamol. Amino acid binds to the central ion through oxygen in the hydroxyl group and nitrogen atom in the amine group (-NH2), whereas paracetamol forms a unipolar bond by binding to the concentrated ion through the oxygen atom in the hydroxyl group. Most of the nickel complexes had octahedral symmetry with valine and paracetamol ligands, while the copper complexes had square or hierarchical to square base symmetry.","PeriodicalId":17299,"journal":{"name":"Journal of the Turkish Chemical Society Section A: Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74926801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The discharge of various types of wastewater into natural streams leads to significant problems by increasing the toxicity of the wastewater. For this reason, methods and materials are being developed by researchers in line with effective, economic, and environmental principles. In this study, the removal of methylene blue, a toxic dyestuff, from aqueous solutions was investigated by synthesizing sodium alginate (SA) and graphene nanoplatelet-sodium alginate composite (SA-GNP) beads. The structural characteristics of the materials were analyzed using FTIR, TGA, optical microscope, and SEM methods. All parameters determining the efficiency of the methylene blue adsorption system were optimized in a batch system. The effects of various factors, such as adsorbent amount, contact time, adsorption temperature, dye concentration, solution pH, pHzpc values of SA and SA-GNP beads, presence of different ions, and beads swelling, on the adsorption process, were investigated. To investigate the mechanism of the adsorption system, the adsorption data were fitted to a non-linear form of the Langmuir, Freundlich, and Temkin equilibrium isotherm models, as well as the Pseudo-first-order (PFO), Pseudo-second-order (PSO), and Bangham kinetic models. High regression coefficients were achieved in the studied kinetic and isotherm models (0.86 ≤ R2 ≤ 0.99), and the experimental data were found to be compatible with the model parameters. Maximum adsorption capacities (qm) of 167.52 mg/g and 290.36 mg/g were obtained for the SA and SA-GNP adsorbents, respectively, at 308 K. The optimum temperature for both adsorption systems was found to be 308 K. The efficiency of methylene blue dyestuff removal was improved with graphene nanoplatelet-based adsorbents.
{"title":"Synthesis of Graphene Nanoplatelet-Alginate Composite Beads and Removal of Methylene Blue from Aqueous Solutions","authors":"Ferda Civan Çavuşoğlu","doi":"10.18596/jotcsa.1196282","DOIUrl":"https://doi.org/10.18596/jotcsa.1196282","url":null,"abstract":"The discharge of various types of wastewater into natural streams leads to significant problems by increasing the toxicity of the wastewater. For this reason, methods and materials are being developed by researchers in line with effective, economic, and environmental principles. In this study, the removal of methylene blue, a toxic dyestuff, from aqueous solutions was investigated by synthesizing sodium alginate (SA) and graphene nanoplatelet-sodium alginate composite (SA-GNP) beads. The structural characteristics of the materials were analyzed using FTIR, TGA, optical microscope, and SEM methods. All parameters determining the efficiency of the methylene blue adsorption system were optimized in a batch system. The effects of various factors, such as adsorbent amount, contact time, adsorption temperature, dye concentration, solution pH, pHzpc values of SA and SA-GNP beads, presence of different ions, and beads swelling, on the adsorption process, were investigated. To investigate the mechanism of the adsorption system, the adsorption data were fitted to a non-linear form of the Langmuir, Freundlich, and Temkin equilibrium isotherm models, as well as the Pseudo-first-order (PFO), Pseudo-second-order (PSO), and Bangham kinetic models. High regression coefficients were achieved in the studied kinetic and isotherm models (0.86 ≤ R2 ≤ 0.99), and the experimental data were found to be compatible with the model parameters. Maximum adsorption capacities (qm) of 167.52 mg/g and 290.36 mg/g were obtained for the SA and SA-GNP adsorbents, respectively, at 308 K. The optimum temperature for both adsorption systems was found to be 308 K. The efficiency of methylene blue dyestuff removal was improved with graphene nanoplatelet-based adsorbents.","PeriodicalId":17299,"journal":{"name":"Journal of the Turkish Chemical Society Section A: Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83960733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Erum Hasan, S. Ali, Ambreen Zia, S. Begum, Salman Tariq Khan, Syed M. Bukhari
The present work describes the successful preparation of iron oxide nanoparticles (NSB1) stabilized with 4-((2-hydroxybenzylidene)amino)benzoic acid. The characterization has been achieved through ultraviolet visible (UV-Vis), fourier transform infra-red (FTIR) spectroscopy and scanning electron microscopy (SEM) with electron dispersive X-ray elemental analysis (EDX). These magnetic nanoparticles have exhibited significant chemosensing properties in the aqueous media to screen Cr3+, Cd2+, Li+, Co2+, Al3+, Pb2+, Ni2+ and Sr2+ ions. However, lead (Pb2+) ions have shown the highest selectivity as compared to other metal ions without any interference in the competitive ion study. The detection limit of Pb2+ ions was found to be 1.7 µM by this nanosensor. The binding ratio and stoichiometry was found to be 1:1 as measured by Job’s plot. The binding strength was also computed through Benesei-Hildebrand equation.
{"title":"Synthesis of Imino Stabilized Iron Oxide Nanosensor for Selective Detection of Lead Ions","authors":"Erum Hasan, S. Ali, Ambreen Zia, S. Begum, Salman Tariq Khan, Syed M. Bukhari","doi":"10.18596/jotcsa.1097197","DOIUrl":"https://doi.org/10.18596/jotcsa.1097197","url":null,"abstract":"The present work describes the successful preparation of iron oxide nanoparticles (NSB1) stabilized with 4-((2-hydroxybenzylidene)amino)benzoic acid. The characterization has been achieved through ultraviolet visible (UV-Vis), fourier transform infra-red (FTIR) spectroscopy and scanning electron microscopy (SEM) with electron dispersive X-ray elemental analysis (EDX). These magnetic nanoparticles have exhibited significant chemosensing properties in the aqueous media to screen Cr3+, Cd2+, Li+, Co2+, Al3+, Pb2+, Ni2+ and Sr2+ ions. However, lead (Pb2+) ions have shown the highest selectivity as compared to other metal ions without any interference in the competitive ion study. The detection limit of Pb2+ ions was found to be 1.7 µM by this nanosensor. The binding ratio and stoichiometry was found to be 1:1 as measured by Job’s plot. The binding strength was also computed through Benesei-Hildebrand equation.","PeriodicalId":17299,"journal":{"name":"Journal of the Turkish Chemical Society Section A: Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89522898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Chaisena, Saranya Wattananon, Samroeng Narakaew
A number of caffeine extraction methods have been developed, such as microwave assisted extraction and ultrasonic-assisted extraction. The disadvantages of these methods are low selectivity, inconvenience, and inefficiency. Among the existing technologies, molecularly imprinted polymers (MIPs) are one of the most efficient and economical methods for the removal of caffeine contaminants. In this study, the objective was to prepare MIPs for the removal of complicated samples. The obtained materials were used as a sorbent for the extraction of caffeine from coffee brewed in an espresso. The MIPs were prepared using konjac/acrylic acid as a functional monomer, N, N′-methylenebisacrylamide as a cross-linker, and caffeine as a template. The chemical structures of MIPs were characterized by Fourier transform infrared spectroscopy. MIPs exhibited a higher maximum adsorption capacity (87.72 mg/g). The equilibrium adsorption data fit well with the Langmuir adsorption isotherm models, which confirm the monolayer adsorption behaviour of caffeine molecules on the surfaces of the MIPs samples. According to the experimental results of the adsorption capacity of caffeine from aqueous solution, the MIPs showed a higher percentage removal of caffeine (75.66%). Our findings suggest that MIPs are useful adsorbents for the decaffeination of coffee brewed in an espresso.
目前已开发了多种咖啡因提取方法，如微波辅助提取法和超声辅助提取法。这些方法的缺点是选择性低、不方便、效率低。在现有的技术中，分子印迹聚合物(MIPs)是去除咖啡因污染物最有效和最经济的方法之一。在本研究中，目的是制备用于去除复杂样品的MIPs。所获得的材料被用作从浓缩咖啡中提取咖啡因的吸附剂。以魔芋/丙烯酸为功能单体，N, N ' -亚甲基双丙烯酰胺为交联剂，咖啡因为模板剂制备了mip。利用傅里叶变换红外光谱对其化学结构进行了表征。MIPs的最大吸附量为87.72 mg/g。平衡吸附数据与Langmuir吸附等温线模型吻合良好，证实了咖啡因分子在MIPs样品表面的单层吸附行为。从对咖啡因的吸附量的实验结果来看，MIPs对咖啡因的去除率较高(75.66%)。我们的研究结果表明，MIPs是一种有用的吸附剂，可以去除浓缩咖啡中的咖啡因。
{"title":"Molecularly Imprinted Polymers Based on Konjac for Selective Caffeine Adsorption in Aqueous Solution","authors":"A. Chaisena, Saranya Wattananon, Samroeng Narakaew","doi":"10.18596/jotcsa.1194200","DOIUrl":"https://doi.org/10.18596/jotcsa.1194200","url":null,"abstract":"A number of caffeine extraction methods have been developed, such as microwave assisted extraction and ultrasonic-assisted extraction. The disadvantages of these methods are low selectivity, inconvenience, and inefficiency. Among the existing technologies, molecularly imprinted polymers (MIPs) are one of the most efficient and economical methods for the removal of caffeine contaminants. In this study, the objective was to prepare MIPs for the removal of complicated samples. The obtained materials were used as a sorbent for the extraction of caffeine from coffee brewed in an espresso. The MIPs were prepared using konjac/acrylic acid as a functional monomer, N, N′-methylenebisacrylamide as a cross-linker, and caffeine as a template. The chemical structures of MIPs were characterized by Fourier transform infrared spectroscopy. MIPs exhibited a higher maximum adsorption capacity (87.72 mg/g). The equilibrium adsorption data fit well with the Langmuir adsorption isotherm models, which confirm the monolayer adsorption behaviour of caffeine molecules on the surfaces of the MIPs samples. According to the experimental results of the adsorption capacity of caffeine from aqueous solution, the MIPs showed a higher percentage removal of caffeine (75.66%). Our findings suggest that MIPs are useful adsorbents for the decaffeination of coffee brewed in an espresso.","PeriodicalId":17299,"journal":{"name":"Journal of the Turkish Chemical Society Section A: Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82459585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A study was undertaken to evaluate the amino acid composition of the seeds of Trigonella cylindracea Desv., Trigonella mesopotamica Hub.-Mor. and Trigonella smyrnea Boiss. which are growing wild in Turkey. The seeds of three species contain both essential (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, valine, arginine, and tryptophan) and non-essential (alanine, aspartic acid, glycine, glutamic acid, proline, serine, and tyrosine) amino acids. The major amino acid was glutamic acid with a value of 4819 mg/100 g (T. cylindracea), 5888 mg/100 g (T. mesopotamica) and 4146 mg/100 g (T. smyrnea). Among the essential amino acids, lysine is found at the highest rate in all three species. The highest amount of lysine was found in the seeds of T. mesopotamica, followed by the seeds of T. cylindracea and T. smyrnea (3352±0.02 mg/100 g, 3059±0.03 mg/100 g and 2947±0.04 mg/100 g, respectively). The literature review showed that the amino acid composition of the studied seeds were evaluated for the first time in this study, therefore; our study provides important preliminary data to the literature in terms of evaluating the chemical compositions of three Trigonella species.
{"title":"Amino Acid Content of Some Species from Trigonella L. Genus Collected from Turkey","authors":"Şerife Selma URAS GÜNGÖR","doi":"10.18596/jotcsa.1177340","DOIUrl":"https://doi.org/10.18596/jotcsa.1177340","url":null,"abstract":"A study was undertaken to evaluate the amino acid composition of the seeds of Trigonella cylindracea Desv., Trigonella mesopotamica Hub.-Mor. and Trigonella smyrnea Boiss. which are growing wild in Turkey. The seeds of three species contain both essential (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, valine, arginine, and tryptophan) and non-essential (alanine, aspartic acid, glycine, glutamic acid, proline, serine, and tyrosine) amino acids. The major amino acid was glutamic acid with a value of 4819 mg/100 g (T. cylindracea), 5888 mg/100 g (T. mesopotamica) and 4146 mg/100 g (T. smyrnea). Among the essential amino acids, lysine is found at the highest rate in all three species. The highest amount of lysine was found in the seeds of T. mesopotamica, followed by the seeds of T. cylindracea and T. smyrnea (3352±0.02 mg/100 g, 3059±0.03 mg/100 g and 2947±0.04 mg/100 g, respectively). The literature review showed that the amino acid composition of the studied seeds were evaluated for the first time in this study, therefore; our study provides important preliminary data to the literature in terms of evaluating the chemical compositions of three Trigonella species.","PeriodicalId":17299,"journal":{"name":"Journal of the Turkish Chemical Society Section A: Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79498867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
New compounds based on 6-hydrazinyl-1,3,4-trimethyl-1H-pyrazolo[3,4-b]pyridine (3a and 3b) were synthesized and characterized by FTIR and 1H/13C NMR spectroscopic methods and their in vitro acetylcholinesterase (AChE) inhibition studies were evaluated. Compound 3b (IC50 value 104.4 µM) exhibited stronger AChE inhibitory activity than the reference galantamine compound (IC50 value 139.4 µM). Molecular docking studies were performed to determine the key interactions and possible binding modes between AChE of compounds. The most active one, 3b, showed a binding affinity of -10.28 kcal/mol.
{"title":"Acetylcholinesterase Inhibition Properties and Docking Studies of Compounds Based on 6-Hydrazinyl-1,3,4-Trimethyl-1H-Pyrazolo[3,4-b]Pyridine","authors":"S. A. Güngör","doi":"10.18596/jotcsa.1117324","DOIUrl":"https://doi.org/10.18596/jotcsa.1117324","url":null,"abstract":"New compounds based on 6-hydrazinyl-1,3,4-trimethyl-1H-pyrazolo[3,4-b]pyridine (3a and 3b) were synthesized and characterized by FTIR and 1H/13C NMR spectroscopic methods and their in vitro acetylcholinesterase (AChE) inhibition studies were evaluated. Compound 3b (IC50 value 104.4 µM) exhibited stronger AChE inhibitory activity than the reference galantamine compound (IC50 value 139.4 µM). Molecular docking studies were performed to determine the key interactions and possible binding modes between AChE of compounds. The most active one, 3b, showed a binding affinity of -10.28 kcal/mol.","PeriodicalId":17299,"journal":{"name":"Journal of the Turkish Chemical Society Section A: Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85087431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Herein, the copper-based electrodes were successfully synthesized with galvanostatic electrodeposition method. The effect of materials obtained at different concentrations of ASA and anodization times on glucose sensing ability was investigated. During the anodization of copper foil in the presence of ASA molecules, it formed a tree branch-like structure connected to each other while decorating the electrode surface. The Cu(30)/ASA(0.02) electrode exhibited a relatively wide linear range (0.2 – 10.0 mM) and a low detection limit (0.826 µM). These excellent activities were mainly attributed to the surface morphology, which functions as highly active sites and enhanced electronic conductive pathways with the addition of ASA. In addition, the stability obtained together with the excellent sensing ability in beverages makes the electrodes useful for practical applications.
{"title":"A Highly Sensitive Non-Enzymatic Sensor for the Determination of Glucose Based on Aniline-2-sulfonic acid-Modified Cu Electrode","authors":"M. B. Arvas","doi":"10.18596/jotcsa.1182942","DOIUrl":"https://doi.org/10.18596/jotcsa.1182942","url":null,"abstract":"Herein, the copper-based electrodes were successfully synthesized with galvanostatic electrodeposition method. The effect of materials obtained at different concentrations of ASA and anodization times on glucose sensing ability was investigated. During the anodization of copper foil in the presence of ASA molecules, it formed a tree branch-like structure connected to each other while decorating the electrode surface. The Cu(30)/ASA(0.02) electrode exhibited a relatively wide linear range (0.2 – 10.0 mM) and a low detection limit (0.826 µM). These excellent activities were mainly attributed to the surface morphology, which functions as highly active sites and enhanced electronic conductive pathways with the addition of ASA. In addition, the stability obtained together with the excellent sensing ability in beverages makes the electrodes useful for practical applications.","PeriodicalId":17299,"journal":{"name":"Journal of the Turkish Chemical Society Section A: Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86126315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Y. Erwa, Asmo Hassan, Raza Salim, Omer Adam Omer Ishag, M. Ahmed
The catalytic performance of potassium hydroxide supported on alumina (KOH/Al2O3) for transesterification of waste cooking oil (WCO) was investigated. XRD, FTIR, and SEM techniques were used to characterize the catalyst after it had been synthesized using the wet impregnation method. The properties of the WCO and the produced biodiesel were evaluated. The main fatty acids of WCO were linoleic (45.61%), elaidic (33.86%), palmitic (10.32%), and stearic acid (4.80%), the acid value (2.29 mg KOH/g), FFA (1.15%), density at 25 °C (0.91 g/cm3), viscosity at 40 °C (34.09 mm2/s), water content (0.0017%), and flash point (206 °C). The XRD pattern of the catalyst showed diffraction peaks of KAlO2 attributed to the orthorhombic crystal system having a 12.46% degree of crystallinity. The SEM micrographs confirmed the amorphous nature of the catalyst. The presence of K–O and Al–O bonds in the catalyst was confirmed by the FTIR. A biodiesel yield of 86.6% was achieved with the following variables: oil to methanol ratio of 1:4, catalyst loading of 1.5% (w/v%), reaction temperature of 55 °C, and a reaction time of 1 h. The results appeared to show a decreasing pattern of yield after 4 cycles of reaction from 86.60 to 51.50%. The fuel properties were density (0.8919 g/cm3), viscosity (7.428 cSt), flash point (65 °C), acid number (0.54 mg KOH/g) and water content (0.0196%). Furthermore, the properties of the prepared biodiesel have been found to comply with the ASTM and EN standard specifications. This catalyst showed promising results for manufacturing biodiesel from low-cost feedstock.
{"title":"Production of Biodiesel from Waste Cooking Oil Using KOH/Al2O3 as a Heterogeneous Catalyst","authors":"I. Y. Erwa, Asmo Hassan, Raza Salim, Omer Adam Omer Ishag, M. Ahmed","doi":"10.18596/jotcsa.1163670","DOIUrl":"https://doi.org/10.18596/jotcsa.1163670","url":null,"abstract":"The catalytic performance of potassium hydroxide supported on alumina (KOH/Al2O3) for transesterification of waste cooking oil (WCO) was investigated. XRD, FTIR, and SEM techniques were used to characterize the catalyst after it had been synthesized using the wet impregnation method. The properties of the WCO and the produced biodiesel were evaluated. The main fatty acids of WCO were linoleic (45.61%), elaidic (33.86%), palmitic (10.32%), and stearic acid (4.80%), the acid value (2.29 mg KOH/g), FFA (1.15%), density at 25 °C (0.91 g/cm3), viscosity at 40 °C (34.09 mm2/s), water content (0.0017%), and flash point (206 °C). The XRD pattern of the catalyst showed diffraction peaks of KAlO2 attributed to the orthorhombic crystal system having a 12.46% degree of crystallinity. The SEM micrographs confirmed the amorphous nature of the catalyst. The presence of K–O and Al–O bonds in the catalyst was confirmed by the FTIR. A biodiesel yield of 86.6% was achieved with the following variables: oil to methanol ratio of 1:4, catalyst loading of 1.5% (w/v%), reaction temperature of 55 °C, and a reaction time of 1 h. The results appeared to show a decreasing pattern of yield after 4 cycles of reaction from 86.60 to 51.50%. The fuel properties were density (0.8919 g/cm3), viscosity (7.428 cSt), flash point (65 °C), acid number (0.54 mg KOH/g) and water content (0.0196%). Furthermore, the properties of the prepared biodiesel have been found to comply with the ASTM and EN standard specifications. This catalyst showed promising results for manufacturing biodiesel from low-cost feedstock.","PeriodicalId":17299,"journal":{"name":"Journal of the Turkish Chemical Society Section A: Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79491190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A less environmentally harmful reagent, 2-tert-Butyl-4-methoxyphenol (BHA), is used to evaluate Metoclopramide hydrochloride (MCP.H) by simple, rapid, sensitive, accurate and precise spectrophotometric method, through azo coupling reaction between metoclopramide hydrochloride medicine and it's pharmaceutical preparation by utilizing BHA as a reagent, (MCP.H) azo-dye formed shows the higher absorption peak at 504 nm. Absorbance- concentration relation is linear over the range from 20 to 280 µg / 5 mL, (i.e. 4-56 ppm) with a good sensitivity (molar absorptivity 0.26x104 L.mol-1. cm-1); good precision (RSD better than 0.844 %) and high accuracy (relative error less than + 0.4%), Sandell's sensitivity index is -0.1293 µg.cm-2, the calculated limit of detection (LOD) is 0.0658 µg/mL and the evaluated limit of quantitation (LOQ) is 0.2193 µg/mL. The application has had successful results for the assay of metoclopramide hydrochloride in dosage forms of tablets and injection.
{"title":"Novel Green Method for the Spectrophotometric Determination of Metoclopramide Hydrochloride in Pharmaceutical Formulations","authors":"Ghufran A. ALHAMMADİ, Lamya A. SARSAM","doi":"10.18596/jotcsa.1158403","DOIUrl":"https://doi.org/10.18596/jotcsa.1158403","url":null,"abstract":"A less environmentally harmful reagent, 2-tert-Butyl-4-methoxyphenol (BHA), is used to evaluate Metoclopramide hydrochloride (MCP.H) by simple, rapid, sensitive, accurate and precise spectrophotometric method, through azo coupling reaction between metoclopramide hydrochloride medicine and it's pharmaceutical preparation by utilizing BHA as a reagent, (MCP.H) azo-dye formed shows the higher absorption peak at 504 nm. Absorbance- concentration relation is linear over the range from 20 to 280 µg / 5 mL, (i.e. 4-56 ppm) with a good sensitivity (molar absorptivity 0.26x104 L.mol-1.\u0000cm-1); good precision (RSD better than 0.844 %) and high accuracy (relative error less than + 0.4%), Sandell's sensitivity index is -0.1293 µg.cm-2, the calculated limit of detection (LOD) is 0.0658 µg/mL and the evaluated limit of quantitation (LOQ) is 0.2193 µg/mL. The application has had successful results for the assay of metoclopramide hydrochloride in dosage forms of tablets and injection.","PeriodicalId":17299,"journal":{"name":"Journal of the Turkish Chemical Society Section A: Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79662814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Emenike, C.H. Okoroafor, O. Okike, Dare Daramola, Omolara Arohunmolase
Vitamin C is considered an essential vitamin that is commonly found in most fruits and vegetables. It is susceptible to easy degradation, especially during pre-treatment and storage. This study aimed at forecasting the degradation of vitamin C in commonly consumed vegetable (cabbage) dipped in different pre-treatment solutions at different time intervals. The samples after dipping at different time intervals were prepared for analysis. Evaluation of the ascorbic acid content of the vegetable was determined using High-Performance Liquid Chromatography (HPLC). This consists of an isocratic elution procedure with ultraviolet-visible detection at 245 nm. The half-lives and rate constants were calculated using the integrated law method. Forecasts were determined using time series analysis. Degradation of vitamin C in this study followed a first-order kinetic model, and the average coefficient of determination (R2-value) was greater than 0.9413. The rate constants of vitamin C degradation for the vegetable dipped in different pretreatment solutions (sodium chloride, sodium benzoate, sodium metabisulfite and vinegar) at different time intervals were 0.0804, 0.1049, 0.0706 and 0.0553 minutes-1; half-lives were 8.2322, 7.3896, 10.9675, and 12.1086 minutes, respectively. The vegetable dipped in different pretreatments for 90 minutes exhibited ln(C) forecast of -2.2057, -4.6307, -1.1746, and 0.0789, respectively. The coefficient of correlation for sodium chloride, sodium benzoate, sodium metabisulfite, and vinegar are 0.084, 0.093, 0.063 and 0.059 respectively. The kinetic models were formulated using predicted initial contents, processing time, and measured contents. The vegetable dipped in vinegar pretreatment solution using ln(C) =ln(C0) - 0.0553t gave the best model. From the results, the most appropriate pretreatment solution for enhancing the shelf life of cabbage is synthetic vinegar (prepared from acetic acid) because it has a lower rate constant, lower coefficient of correlation, and the longest half-life.
维生素C被认为是一种必需的维生素，通常存在于大多数水果和蔬菜中。它很容易降解，特别是在预处理和储存期间。本研究旨在预测食用蔬菜(白菜)中维生素C在不同时间间隔浸在不同预处理溶液中的降解情况。以不同时间间隔浸渍后的样品制备用于分析。采用高效液相色谱法测定了该蔬菜的抗坏血酸含量。这包括一个等温洗脱程序，在245 nm处进行紫外可见检测。用积分定律法计算了半衰期和速率常数。预测是通过时间序列分析确定的。本研究对维生素C的降解符合一级动力学模型，平均决定系数(r2值)大于0.9413。不同预处理溶液(氯化钠、苯甲酸钠、焦亚硫酸钠和醋)在不同时间间隔下对蔬菜维生素C的降解速率常数分别为0.0804、0.1049、0.0706和0.0553 min -1;半衰期分别为8.2322分钟、7.3896分钟、10.9675分钟和12.1086分钟。不同预处理条件下浸泡90 min的ln(C)预测值分别为-2.2057、-4.6307、-1.1746和0.0789。氯化钠、苯甲酸钠、焦亚硫酸钠和食醋的相关系数分别为0.084、0.093、0.063和0.059。利用预测的初始含量、处理时间和测定的含量建立了动力学模型。以ln(C) =ln(C0) - 0.0553t的醋预处理溶液浸泡蔬菜为最佳模型。结果表明，以醋酸为原料制备的合成醋具有较低的速率常数、较低的相关系数和较长的半衰期，是提高白菜保质期的最佳预处理溶液。
{"title":"Forecasting the Degradation of Vitamin C Concentration in Commonly Consumed Vegetable Cabbage (Brassica oleracea) dipped in Different Pre-treatment Solutions","authors":"A. Emenike, C.H. Okoroafor, O. Okike, Dare Daramola, Omolara Arohunmolase","doi":"10.18596/jotcsa.1093112","DOIUrl":"https://doi.org/10.18596/jotcsa.1093112","url":null,"abstract":"Vitamin C is considered an essential vitamin that is commonly found in most fruits and vegetables. It is susceptible to easy degradation, especially during pre-treatment and storage. This study aimed at forecasting the degradation of vitamin C in commonly consumed vegetable (cabbage) dipped in different pre-treatment solutions at different time intervals. The samples after dipping at different time intervals were prepared for analysis. Evaluation of the ascorbic acid content of the vegetable was determined using High-Performance Liquid Chromatography (HPLC). This consists of an isocratic elution procedure with ultraviolet-visible detection at 245 nm. The half-lives and rate constants were calculated using the integrated law method. Forecasts were determined using time series analysis. Degradation of vitamin C in this study followed a first-order kinetic model, and the average coefficient of determination (R2-value) was greater than 0.9413. The rate constants of vitamin C degradation for the vegetable dipped in different pretreatment solutions (sodium chloride, sodium benzoate, sodium metabisulfite and vinegar) at different time intervals were 0.0804, 0.1049, 0.0706 and 0.0553 minutes-1; half-lives were 8.2322, 7.3896, 10.9675, and 12.1086 minutes, respectively. The vegetable dipped in different pretreatments for 90 minutes exhibited ln(C) forecast of -2.2057, -4.6307, -1.1746, and 0.0789, respectively. The coefficient of correlation for sodium chloride, sodium benzoate, sodium metabisulfite, and vinegar are 0.084, 0.093, 0.063 and 0.059 respectively. The kinetic models were formulated using predicted initial contents, processing time, and measured contents. The vegetable dipped in vinegar pretreatment solution using ln(C) =ln(C0) - 0.0553t gave the best model. From the results, the most appropriate pretreatment solution for enhancing the shelf life of cabbage is synthetic vinegar (prepared from acetic acid) because it has a lower rate constant, lower coefficient of correlation, and the longest half-life.","PeriodicalId":17299,"journal":{"name":"Journal of the Turkish Chemical Society Section A: Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72945161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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