Pub Date : 2020-06-01DOI: 10.22036/PCR.2020.196847.1657
M. Joshipura, N. Shah, Sudir Dabke
Predicting physical properties is one of the major requirements in process engineering. Equations of state (EoS) are widely used for predicting physical properties. Among many EoS, cubic equations of state (cubic EoS) are being used because they are simple and applicable over a wide range of temperature and pressure. However, these cubic EoS fail to predict properties of a compound having polarity, association as well as hydrogen bonding. In the present study a new generalization for cohesion factor, to be used with Peng-Robinson (PR) EoS was proposed. In developing the model, compound-specific parameters for nearly 300 compounds were generated. These compound-specific parameters were correlated in terms of the reduced dipole moment and critical compressibility factor. Proposed models were compared with models available in the literature. Vapor pressure, heat of vaporization, saturated liquid density and second virial coefficient of the compounds were predicted. It was observed that the models with reduced dipole predicted various properties accurately for highly polar compounds without losing accuracy in predicting properties for non-polar compounds.
预测物理性质是过程工程的主要要求之一。状态方程(EoS)被广泛用于预测物理性质。在许多状态方程中，立方状态方程(cubic equation of state，简称cubic EoS)因其简单且适用于广泛的温度和压力范围而被广泛使用。然而，这些立方方程不能预测具有极性、缔合和氢键的化合物的性质。本文提出了一种适用于Peng-Robinson (PR)方程的内聚因子的新概化方法。在开发模型的过程中，生成了近300种化合物的特定参数。这些化合物的特定参数与约简偶极矩和临界压缩系数相关。将提出的模型与文献中现有的模型进行比较。对化合物的蒸汽压、汽化热、饱和液体密度和第二维里系数进行了预测。结果表明，偶极子化简后的模型能准确预测高极性化合物的各种性质，而对非极性化合物的预测精度不降低。
{"title":"New Generalization of Cohesion Factor Model for Polar Compounds: Peng-Robinson Equation of State","authors":"M. Joshipura, N. Shah, Sudir Dabke","doi":"10.22036/PCR.2020.196847.1657","DOIUrl":"https://doi.org/10.22036/PCR.2020.196847.1657","url":null,"abstract":"Predicting physical properties is one of the major requirements in process engineering. Equations of state (EoS) are widely used for predicting physical properties. Among many EoS, cubic equations of state (cubic EoS) are being used because they are simple and applicable over a wide range of temperature and pressure. However, these cubic EoS fail to predict properties of a compound having polarity, association as well as hydrogen bonding. In the present study a new generalization for cohesion factor, to be used with Peng-Robinson (PR) EoS was proposed. In developing the model, compound-specific parameters for nearly 300 compounds were generated. These compound-specific parameters were correlated in terms of the reduced dipole moment and critical compressibility factor. Proposed models were compared with models available in the literature. Vapor pressure, heat of vaporization, saturated liquid density and second virial coefficient of the compounds were predicted. It was observed that the models with reduced dipole predicted various properties accurately for highly polar compounds without losing accuracy in predicting properties for non-polar compounds.","PeriodicalId":20084,"journal":{"name":"Physical Chemistry Research","volume":"8 1","pages":"355-364"},"PeriodicalIF":1.2,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45490358","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}
Pub Date : 2020-06-01DOI: 10.22036/PCR.2020.214856.1718
Timmeswara Sarma Nori, C. Srinivasu, Sk Baba Vali, P. S. Sastry
Viscosities and densities are measured experimentally for three binary liquid mixtures of Aniline + Toluene, Aniline + o-Xylene and Aniline + Mesitylene using Ostwald’s viscometer and Specific gravity bottle at T = 303.15 K. Viscosities have also been calculated using empirical relations viz., Bingham relation, Kendall-Munroe relation, Arrhenius -Eyring relation, Croenaurer-Rothfus-Kermore relation and Gambrill relation. The validity of these correlations has been verified by respective deviations between calculated values and experimental values. These results show that positive deviations are present in all the three binary mixtures at T = 303.15 K. The results of all the relations are comparatively in good agreement with experimental results. These are used to draw the characteristics of the molecular association among the components of respective binary liquid mixtures.
{"title":"Estimation of Viscosities and Their Deviations in Organic Liquid Mixtures at 303.15 K-A Comparative Study","authors":"Timmeswara Sarma Nori, C. Srinivasu, Sk Baba Vali, P. S. Sastry","doi":"10.22036/PCR.2020.214856.1718","DOIUrl":"https://doi.org/10.22036/PCR.2020.214856.1718","url":null,"abstract":"Viscosities and densities are measured experimentally for three binary liquid mixtures of Aniline + Toluene, Aniline + o-Xylene and Aniline + Mesitylene using Ostwald’s viscometer and Specific gravity bottle at T = 303.15 K. Viscosities have also been calculated using empirical relations viz., Bingham relation, Kendall-Munroe relation, Arrhenius -Eyring relation, Croenaurer-Rothfus-Kermore relation and Gambrill relation. The validity of these correlations has been verified by respective deviations between calculated values and experimental values. These results show that positive deviations are present in all the three binary mixtures at T = 303.15 K. The results of all the relations are comparatively in good agreement with experimental results. These are used to draw the characteristics of the molecular association among the components of respective binary liquid mixtures.","PeriodicalId":20084,"journal":{"name":"Physical Chemistry Research","volume":"8 1","pages":"365-372"},"PeriodicalIF":1.2,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49250103","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}
Pub Date : 2020-06-01DOI: 10.22036/PCR.2020.205099.1686
Wan Zhong-Yu
Based on topological chemistry theory, a quantum chemistry method is used to calculate the 91 electrical distance vector (Mi) of a molecule, which is used to characterize the chemical microenvironment in which the molecule is located. The multivariate stepwise regression method was used to screen the variables to obtain the ternary best equation. Correlation coefficient R2=0.887, R2CV=0.673, passed by FIT and AIC .The ternary variable is used as the input set, and the inhibition rate is used as the output set. The LS-SVM and Elman-ANN algorithms are used for prediction and comparison. The results show that R2 is 0.993 and 0.994 respectively. The prediction ability is similar. But the stability of Elman is better, and the two-dimensional structure affecting the molecule is structural fragments such as =CH-, -CH<.
{"title":"QSAR Study of Arylpyridone Oxime Based on the SVM and Elman Algorithms","authors":"Wan Zhong-Yu","doi":"10.22036/PCR.2020.205099.1686","DOIUrl":"https://doi.org/10.22036/PCR.2020.205099.1686","url":null,"abstract":"Based on topological chemistry theory, a quantum chemistry method is used to calculate the 91 electrical distance vector (Mi) of a molecule, which is used to characterize the chemical microenvironment in which the molecule is located. The multivariate stepwise regression method was used to screen the variables to obtain the ternary best equation. Correlation coefficient R2=0.887, R2CV=0.673, passed by FIT and AIC .The ternary variable is used as the input set, and the inhibition rate is used as the output set. The LS-SVM and Elman-ANN algorithms are used for prediction and comparison. The results show that R2 is 0.993 and 0.994 respectively. The prediction ability is similar. But the stability of Elman is better, and the two-dimensional structure affecting the molecule is structural fragments such as =CH-, -CH<.","PeriodicalId":20084,"journal":{"name":"Physical Chemistry Research","volume":"8 1","pages":"215-223"},"PeriodicalIF":1.2,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42447442","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}
Pub Date : 2020-06-01DOI: 10.22036/PCR.2020.212523.1709
M. Janighorban, N. Sohrabi, N. Rasouli, M. Ghaedi
Modified Zn2Al-layered double hydroxide (LDH) intercalated with Quinoline Yellow (Q) (Zn2Al-LDH/Q) was prepared by a facile and simple method and then used to remove of Cd2+ ions from water. The chemical composition and morphology of Zn2Al-LDH/Q was investigated by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Field emission Scanning electron microscopy (FE-SEM) and Energy-dispersive X-ray spectroscopy. Response surface methodology was employed to optimize the adsorption parameters of Cd2+ Such optimization was undertaken to ensure a high efficiency over the experimental ranges employed and to evaluate the interactive effects of the initial concentration of Cd2+, pH, adsorbent dosage, temperature and contact time in order to improve the conditions employed in the batch process. The analysis of variance (ANOVA) indicated that a second-order polynomial regression equation was the most appropriate polynomial for fitting the experimental data. The experimental confirmation tests showed a correlation between the predicted and experimental responses (R2). The optimum adsorption parameters were predicted as an initial Cd2+ concentration of 35 mg l-1, a pH value of 4.17, the adsorbent dosage of 0.03 g/L, a temperature of 32.5 °C and contact time of 51 min. Under optimum conditions, the highest adsorption efficiency and maximum adsorption capacity were 45% and 12.18 mg/g, respectively.
{"title":"Response Surface Methodology (RSM) for Statistical Optimization of Cd2+ Removal Using Modified Zn2Al-layer Double Hydroxide by Quinoline Yellow","authors":"M. Janighorban, N. Sohrabi, N. Rasouli, M. Ghaedi","doi":"10.22036/PCR.2020.212523.1709","DOIUrl":"https://doi.org/10.22036/PCR.2020.212523.1709","url":null,"abstract":"Modified Zn2Al-layered double hydroxide (LDH) intercalated with Quinoline Yellow (Q) (Zn2Al-LDH/Q) was prepared by a facile and simple method and then used to remove of Cd2+ ions from water. The chemical composition and morphology of Zn2Al-LDH/Q was investigated by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Field emission Scanning electron microscopy (FE-SEM) and Energy-dispersive X-ray spectroscopy. Response surface methodology was employed to optimize the adsorption parameters of Cd2+ Such optimization was undertaken to ensure a high efficiency over the experimental ranges employed and to evaluate the interactive effects of the initial concentration of Cd2+, pH, adsorbent dosage, temperature and contact time in order to improve the conditions employed in the batch process. The analysis of variance (ANOVA) indicated that a second-order polynomial regression equation was the most appropriate polynomial for fitting the experimental data. The experimental confirmation tests showed a correlation between the predicted and experimental responses (R2). The optimum adsorption parameters were predicted as an initial Cd2+ concentration of 35 mg l-1, a pH value of 4.17, the adsorbent dosage of 0.03 g/L, a temperature of 32.5 °C and contact time of 51 min. Under optimum conditions, the highest adsorption efficiency and maximum adsorption capacity were 45% and 12.18 mg/g, respectively.","PeriodicalId":20084,"journal":{"name":"Physical Chemistry Research","volume":"8 1","pages":"313-341"},"PeriodicalIF":1.2,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41880718","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}
Pub Date : 2020-06-01DOI: 10.22036/PCR.2020.208933.1699
Najmeh Tazang, Farzad Alavi, J. Javanmardi
An accurate prediction of the absorption and desorption of Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX) is important for the estimation of BTEX emissions from glycol units in natural gas processing plants. This work presents an approach to accurately model the solubilities of BTEX in triethylene glycol (TEG). The absorption of gases studied in this work into TEG is physical in nature, and therefore is treated as physisorption in modeling. The Huang-Radosz version of Statistical Associating Fluid Theory (SAFT-HR) Equation of State (EoS) was utilized to estimate the solubilities of BTEX in TEG. A new set of SAFT parameters for TEG, as well as a new set of binary interaction parameters between TEG and other components were obtained by fitting experimental vapor pressure and liquid density of TEG and available experimental binary VLE data, respectively. Using these parameters, solubility of multicomponent gases in TEG are accurately predicted. To have an estimate of the relative accuracy of SAFT-HR EoS, the results from Perturbed–Chain SAFT (PC–SAFT) and Peng–Robinson (PR) EoS are also reported. The overall average of root–mean–square deviation (RMSD) for binary and ternary systems studied in this work, using SAFT-HR, PC–SAFT, and PR EoS obtained equal to 0.12, 0.20, and 1.56, respectively.
{"title":"Estimation of Solubility of BTEX, Light Hydrocarbons and Sour Gases in Triethylene Glycol Using the SAFT Equation of State","authors":"Najmeh Tazang, Farzad Alavi, J. Javanmardi","doi":"10.22036/PCR.2020.208933.1699","DOIUrl":"https://doi.org/10.22036/PCR.2020.208933.1699","url":null,"abstract":"An accurate prediction of the absorption and desorption of Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX) is important for the estimation of BTEX emissions from glycol units in natural gas processing plants. This work presents an approach to accurately model the solubilities of BTEX in triethylene glycol (TEG). The absorption of gases studied in this work into TEG is physical in nature, and therefore is treated as physisorption in modeling. The Huang-Radosz version of Statistical Associating Fluid Theory (SAFT-HR) Equation of State (EoS) was utilized to estimate the solubilities of BTEX in TEG. A new set of SAFT parameters for TEG, as well as a new set of binary interaction parameters between TEG and other components were obtained by fitting experimental vapor pressure and liquid density of TEG and available experimental binary VLE data, respectively. Using these parameters, solubility of multicomponent gases in TEG are accurately predicted. To have an estimate of the relative accuracy of SAFT-HR EoS, the results from Perturbed–Chain SAFT (PC–SAFT) and Peng–Robinson (PR) EoS are also reported. The overall average of root–mean–square deviation (RMSD) for binary and ternary systems studied in this work, using SAFT-HR, PC–SAFT, and PR EoS obtained equal to 0.12, 0.20, and 1.56, respectively.","PeriodicalId":20084,"journal":{"name":"Physical Chemistry Research","volume":"8 1","pages":"251-266"},"PeriodicalIF":1.2,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43234724","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}
Pub Date : 2020-06-01DOI: 10.22036/PCR.2020.213260.1713
Khorshid Darvishi-Ganji, Fateme Mirzajani, A. Aliahmadi, Alireza Fakhari-Zavareh, A. Ghassempour
Herein, the protein corona formation on the spherical metal nanoparticles was studied to investigate the possible effects of silver nanoparticles (AgNPs) on the protein activity and conformation. The digestion capability of trypsin was monitored on the human serum albumin (HSA) at standard enzymatic hydrolysis conditions in the absence and presence of different concentrations of AgNPs. So the ratio of enzyme:HSA, the duration and the temperature of nanoparticle treatment were evaluated. The activity of treated trypsin molecules, in the form of hard (HC) and soft corona (SC) were studied using sodium dodecyl sulfate poly acrylamide gel electrophoresis (SDS-PAGE), and nano liquid chromatography electrospray (ion trap) mass spectrometry (nano LC-ESI/MS, LC-ESI/MS). In addition the characteristics of silver nanoparticles and the formation of HSA corona on the nanoparticle surface were monitored using ultra-violet/visible spectroscopy (UV-Vis), Dynamic light scattering (DLS) and fluorescence spectrophotometry. The results demonstrated that not only the corona formation but also the AgNPs/Trypsin interaction, decreases the hydrolysis potency of trypsin. Furthermore, the encountering of the AgNPs/HSA could influence both nanoparticles and HSA molecule features. Accompanied with fluorescence study, that the HSA secondary structure. Also LC-ESI/MS data revealed the most affected HSA triptics have α-helix structure.
{"title":"Silver Nanoparticle Trypsin Corona Formation and the Impacts on Enzymatic Potency","authors":"Khorshid Darvishi-Ganji, Fateme Mirzajani, A. Aliahmadi, Alireza Fakhari-Zavareh, A. Ghassempour","doi":"10.22036/PCR.2020.213260.1713","DOIUrl":"https://doi.org/10.22036/PCR.2020.213260.1713","url":null,"abstract":"Herein, the protein corona formation on the spherical metal nanoparticles was studied to investigate the possible effects of silver nanoparticles (AgNPs) on the protein activity and conformation. The digestion capability of trypsin was monitored on the human serum albumin (HSA) at standard enzymatic hydrolysis conditions in the absence and presence of different concentrations of AgNPs. So the ratio of enzyme:HSA, the duration and the temperature of nanoparticle treatment were evaluated. The activity of treated trypsin molecules, in the form of hard (HC) and soft corona (SC) were studied using sodium dodecyl sulfate poly acrylamide gel electrophoresis (SDS-PAGE), and nano liquid chromatography electrospray (ion trap) mass spectrometry (nano LC-ESI/MS, LC-ESI/MS). In addition the characteristics of silver nanoparticles and the formation of HSA corona on the nanoparticle surface were monitored using ultra-violet/visible spectroscopy (UV-Vis), Dynamic light scattering (DLS) and fluorescence spectrophotometry. The results demonstrated that not only the corona formation but also the AgNPs/Trypsin interaction, decreases the hydrolysis potency of trypsin. Furthermore, the encountering of the AgNPs/HSA could influence both nanoparticles and HSA molecule features. Accompanied with fluorescence study, that the HSA secondary structure. Also LC-ESI/MS data revealed the most affected HSA triptics have α-helix structure.","PeriodicalId":20084,"journal":{"name":"Physical Chemistry Research","volume":"8 1","pages":"241-250"},"PeriodicalIF":1.2,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43618277","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}
Pub Date : 2020-06-01DOI: 10.22036/PCR.2020.214026.1717
M. Abdul-Hammed, B. Semire, Ebhohimen Ehizuelen Israel, A. Oyebamiji, T. Olowolafe
Inhibition of cyclooxygenase-2 (COX-2) and thymidylate Synthase (TS) enzymes play prominent chemopreventive and chemotherapeutic roles in colorectal cancer studies. Basic computational investigation on the inhibition of these enzymes by sphingomyelin (SM) derivatives was carried out in silico using Density Functional Theory (DFT) and molecular docking studies. Interactions between SM with unsaturated fatty acids, COX-2 and TS were compared with that of 5-Fluorouracil (5-FU) and Celecoxib, the standard anti-colorectal cancer drugs. The results showed that SM with alpha-linoleic acid derivative possesses the highest HOMO (-4.70 eV) and lowest LUMO (0.09 eV) energies, which may enhance their interactions with their target receptors. All SM molecules, irrespective of the fatty acid nature have lower binding affinities, (ΔG = -5.5 to - 6.8 kcal/mol) against COX-2 than Celecoxib (-10.1 kcal/mol), indicating that the standard COX-2 inhibitor is much stronger than the natural SM. However, some of the natural SM are stronger inhibitors of thymidylate synthase than the standard drug, 5-FU, with SM having alpha-linoleic acid derivative (ΔG = - 6.2 kcal/mol) higher than 5-FU (ΔG = -5.28 kcal/mol), but lower than that of the active drug metabolite, 5-FdUMP (ΔG = - 7.4 kcal/mol). These ligand-protein interactions were all feasible and spontaneous.
{"title":"Inhibition of Cyclooxygenase-2 and Thymidylate Synthase by Dietary Sphingomyelins: Insights from DFT and Molecular Docking Studies","authors":"M. Abdul-Hammed, B. Semire, Ebhohimen Ehizuelen Israel, A. Oyebamiji, T. Olowolafe","doi":"10.22036/PCR.2020.214026.1717","DOIUrl":"https://doi.org/10.22036/PCR.2020.214026.1717","url":null,"abstract":"Inhibition of cyclooxygenase-2 (COX-2) and thymidylate Synthase (TS) enzymes play prominent chemopreventive and chemotherapeutic roles in colorectal cancer studies. Basic computational investigation on the inhibition of these enzymes by sphingomyelin (SM) derivatives was carried out in silico using Density Functional Theory (DFT) and molecular docking studies. Interactions between SM with unsaturated fatty acids, COX-2 and TS were compared with that of 5-Fluorouracil (5-FU) and Celecoxib, the standard anti-colorectal cancer drugs. The results showed that SM with alpha-linoleic acid derivative possesses the highest HOMO (-4.70 eV) and lowest LUMO (0.09 eV) energies, which may enhance their interactions with their target receptors. All SM molecules, irrespective of the fatty acid nature have lower binding affinities, (ΔG = -5.5 to - 6.8 kcal/mol) against COX-2 than Celecoxib (-10.1 kcal/mol), indicating that the standard COX-2 inhibitor is much stronger than the natural SM. However, some of the natural SM are stronger inhibitors of thymidylate synthase than the standard drug, 5-FU, with SM having alpha-linoleic acid derivative (ΔG = - 6.2 kcal/mol) higher than 5-FU (ΔG = -5.28 kcal/mol), but lower than that of the active drug metabolite, 5-FdUMP (ΔG = - 7.4 kcal/mol). These ligand-protein interactions were all feasible and spontaneous.","PeriodicalId":20084,"journal":{"name":"Physical Chemistry Research","volume":"8 1","pages":"297-311"},"PeriodicalIF":1.2,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43646869","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}
Pub Date : 2020-03-01DOI: 10.22036/PCR.2019.205211.1688
Shashanka Rajendrachari, K. Be
In this work, we described a cost-effective and environmentally friendly technique for green synthesis of colloidal silver nanoparticles from aqueous extract of fresh leaves of Acacia melanoxylon and its application as a dopamine and hydrogen peroxide sensor. The prepared silver nanoparticles were characterized by UV-Visible absorption spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), zeta-potential analysis, thermogravimetric analysis (TGA), differential scanning calorimeter (DSC), etc. This method was found to be cost-effective, eco-friendly when compared to that of chemical and physical methods of nanoparticle synthesis. Silver nanoparticles modified carbon paste electrode (CPE) was fabricated for the detection of dopamine and hydrogen peroxide. The fabricated electrode showed an excellent sensitivity towards the oxidation of both dopamine (DA) and hydrogen peroxide (H2O2) in 0.1M phosphate buffer (PBS) solution at a pH 7. The effect of the scan rate, the concentration of the modifier and the analyte were studied by the cyclic voltammetric technique. The result exhibits good electrocatalytic activity, diffusion-controlled process and linear increase in peak current with different concentrations of dopamine and hydrogen peroxide.
{"title":"Biosynthesis of Silver Nanoparticles Using Leaves of Acacia Melanoxylon and their Application as Dopamine and Hydrogen Peroxide Sensors","authors":"Shashanka Rajendrachari, K. Be","doi":"10.22036/PCR.2019.205211.1688","DOIUrl":"https://doi.org/10.22036/PCR.2019.205211.1688","url":null,"abstract":"In this work, we described a cost-effective and environmentally friendly technique for green synthesis of colloidal silver nanoparticles from aqueous extract of fresh leaves of Acacia melanoxylon and its application as a dopamine and hydrogen peroxide sensor. The prepared silver nanoparticles were characterized by UV-Visible absorption spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), zeta-potential analysis, thermogravimetric analysis (TGA), differential scanning calorimeter (DSC), etc. This method was found to be cost-effective, eco-friendly when compared to that of chemical and physical methods of nanoparticle synthesis. Silver nanoparticles modified carbon paste electrode (CPE) was fabricated for the detection of dopamine and hydrogen peroxide. The fabricated electrode showed an excellent sensitivity towards the oxidation of both dopamine (DA) and hydrogen peroxide (H2O2) in 0.1M phosphate buffer (PBS) solution at a pH 7. The effect of the scan rate, the concentration of the modifier and the analyte were studied by the cyclic voltammetric technique. The result exhibits good electrocatalytic activity, diffusion-controlled process and linear increase in peak current with different concentrations of dopamine and hydrogen peroxide.","PeriodicalId":20084,"journal":{"name":"Physical Chemistry Research","volume":"8 1","pages":"1-18"},"PeriodicalIF":1.2,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46868539","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}
Pub Date : 2020-03-01DOI: 10.22036/PCR.2019.176786.1607
F. Mahmoudi, M. Shahraki, Sayeydmosatfa Habibi-khorassani
The effect of different media on the kinetics and mechanism of formation of diethyl (1S, 2S)-3, 3-dibenzoylcyclopropane-1, 2-dicarboxylate was investigated. The reaction was accelerated with changing the medium from non-ionic to ionic. Among the selected ionic salts, NaCl was the best salt to increase the reaction rate of the titled synthesis about 2.5-fold (kobs = 1.295 M-1.min-1 against kobs = 3.105 M-1.min-1). The incremental effect of ionic salts was found to be in this order: NaCl > NaBr > KBr > KCl. Isokinetic plots for the reaction in the presence of different salts were obtained and a linear relationship which indicated an identical mechanism for all reactions, was found. Moreover, the effect of cationic, nonionic, and anionic surfactants on the reaction rate was evaluated. Substantial reduction on the reaction rate and change in the mechanism was observed with the addition of an anionic surfactant such as sodium dodecyl sulfate. The values of activation parameters were also estimated (ΔH‡ = 80.1 ± 0.6 kJ.mol-1, ΔS‡ = 23.9 ± 2.0 J.mol-1.K-1, and ΔG‡ = 72.9 ± 1.1 kJ.mol-1) and the positive value of ΔH‡ confirmed the endothermic process and entropy value referred to an associative mechanism.
{"title":"Effect of Medium on the Kinetics of Stereoselective Synthesis of a Highly Functionalized Cyclopropanesame","authors":"F. Mahmoudi, M. Shahraki, Sayeydmosatfa Habibi-khorassani","doi":"10.22036/PCR.2019.176786.1607","DOIUrl":"https://doi.org/10.22036/PCR.2019.176786.1607","url":null,"abstract":"The effect of different media on the kinetics and mechanism of formation of diethyl (1S, 2S)-3, 3-dibenzoylcyclopropane-1, 2-dicarboxylate was investigated. The reaction was accelerated with changing the medium from non-ionic to ionic. Among the selected ionic salts, NaCl was the best salt to increase the reaction rate of the titled synthesis about 2.5-fold (kobs = 1.295 M-1.min-1 against kobs = 3.105 M-1.min-1). The incremental effect of ionic salts was found to be in this order: NaCl > NaBr > KBr > KCl. Isokinetic plots for the reaction in the presence of different salts were obtained and a linear relationship which indicated an identical mechanism for all reactions, was found. Moreover, the effect of cationic, nonionic, and anionic surfactants on the reaction rate was evaluated. Substantial reduction on the reaction rate and change in the mechanism was observed with the addition of an anionic surfactant such as sodium dodecyl sulfate. The values of activation parameters were also estimated (ΔH‡ = 80.1 ± 0.6 kJ.mol-1, ΔS‡ = 23.9 ± 2.0 J.mol-1.K-1, and ΔG‡ = 72.9 ± 1.1 kJ.mol-1) and the positive value of ΔH‡ confirmed the endothermic process and entropy value referred to an associative mechanism.","PeriodicalId":20084,"journal":{"name":"Physical Chemistry Research","volume":"8 1","pages":"19-30"},"PeriodicalIF":1.2,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45300172","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}
Pub Date : 2020-03-01DOI: 10.22036/PCR.2020.205547.1691
M. Azayez, T. Fergoug, N. Meddah-Araibi, C. Zelmat, Y. Bouhadda
Abstract. . Quantum-chemical calculations were performed to study the complexation of drug molecule procaine hydrochloride with beta cyclodextrin (β-CD) in the gas phase and in water. The inclusion process was optimized by the semi empirical method PM3 and the obtained complex structure was further refined by ONIOM method (DFT: PM3). It is found that (B3LYP/6-31G(d,p) : PM3) provides the best energy minimum for the complex, compared to M06-2X and WB97XD functional. Given the energy profile, the configuration of the complex formed indicates that the benzene ring is completely included in the hydrophobic cavity of the β-CD. The thermodynamic parameters analysis has shown that the procaine/β-CD complexation is enthalpically favorable, and the complex is well structured. Natural bond orbital (NBO) analysis indicates that no hydrogen bond interaction exists, and the procaine/β-CD complex is mainly stabilized by Van der Waals forces. 1D 1H NMR spectra analysis shows that the procaine molecule penetrates into the cavity of this CD with the aromatic ring.
{"title":"Theoretical Investigation of the Complexation Reaction of Procaine-hydrochloride by β-cyclodextrin","authors":"M. Azayez, T. Fergoug, N. Meddah-Araibi, C. Zelmat, Y. Bouhadda","doi":"10.22036/PCR.2020.205547.1691","DOIUrl":"https://doi.org/10.22036/PCR.2020.205547.1691","url":null,"abstract":"Abstract. . Quantum-chemical calculations were performed to study the complexation of drug molecule procaine hydrochloride with beta cyclodextrin (β-CD) in the gas phase and in water. The inclusion process was optimized by the semi empirical method PM3 and the obtained complex structure was further refined by ONIOM method (DFT: PM3). It is found that (B3LYP/6-31G(d,p) : PM3) provides the best energy minimum for the complex, compared to M06-2X and WB97XD functional. Given the energy profile, the configuration of the complex formed indicates that the benzene ring is completely included in the hydrophobic cavity of the β-CD. The thermodynamic parameters analysis has shown that the procaine/β-CD complexation is enthalpically favorable, and the complex is well structured. Natural bond orbital (NBO) analysis indicates that no hydrogen bond interaction exists, and the procaine/β-CD complex is mainly stabilized by Van der Waals forces. 1D 1H NMR spectra analysis shows that the procaine molecule penetrates into the cavity of this CD with the aromatic ring.","PeriodicalId":20084,"journal":{"name":"Physical Chemistry Research","volume":"8 1","pages":"155-165"},"PeriodicalIF":1.2,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43187908","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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