Pub Date : 2015-02-25DOI: 10.6000/1929-5030.2015.04.01.4
V. Karanth, D. Bhat
The partial molar volumes, isentropic compressibilities, partial molar isentropic compressions and transfer molar quantities of cyclic alanylalanine in water and in aqueous solutions of MnCl 2 , NiCl 2 and ZnCl 2 were determined using the experimental density and speed of sound values. Refractive indices of all the solutions were recorded to calculate the molar refractions. The molecular interactions existing in the systems have been discussed based on the derived parameters. It has been found that M 2+ -O 2 H bond distances of hydrated cations influence on the volumetric properties of cyclic alanylalanine. Further, the greater effect of hydrophobic hydration has been substantiated by the S v values of least square fits of apparent molar volume against solute molality.
{"title":"Volumetric Properties of Cyclic Alanylalanine in Aqueous Solutions of MnCl2, NiCl2 and ZnCl2 at Temperatures T = (293.15 to 313.15) K","authors":"V. Karanth, D. Bhat","doi":"10.6000/1929-5030.2015.04.01.4","DOIUrl":"https://doi.org/10.6000/1929-5030.2015.04.01.4","url":null,"abstract":"The partial molar volumes, isentropic compressibilities, partial molar isentropic compressions and transfer molar quantities of cyclic alanylalanine in water and in aqueous solutions of MnCl 2 , NiCl 2 and ZnCl 2 were determined using the experimental density and speed of sound values. Refractive indices of all the solutions were recorded to calculate the molar refractions. The molecular interactions existing in the systems have been discussed based on the derived parameters. It has been found that M 2+ -O 2 H bond distances of hydrated cations influence on the volumetric properties of cyclic alanylalanine. Further, the greater effect of hydrophobic hydration has been substantiated by the S v values of least square fits of apparent molar volume against solute molality.","PeriodicalId":15165,"journal":{"name":"Journal of Applied Solution Chemistry and Modeling","volume":"89 1","pages":"48-62"},"PeriodicalIF":0.0,"publicationDate":"2015-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78367646","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 : 2015-02-25DOI: 10.6000/1929-5030.2015.04.01.1
A. Mehrkesh, T. Tavakoli, M. Hatamipour
Lubricating base oil is commonly extracted from lube-oil cut, a petroleum cut, with the use of an aromatic solvent. Aromatic content of the final product is an important criterion specifying the product quality. The aromatic removal process to produce the lubricating oil should be carried out in a Liquid-Liquid extraction column. In a typical solvent extraction process, solvent to feed ratio, solvent and feed temperatures, agitation rate, and settling time could directly affect the yield of extraction. In the current study, the effect of agitation rate and settling time on the yield of extraction was studied. It was found that a settling time of 2hrs and an agitation rate of 430 RPM to be the optimum parameters of the extraction process.
{"title":"Effect of Operating Conditions of the Extraction Process on the Physical Properties of Lubricating Oil","authors":"A. Mehrkesh, T. Tavakoli, M. Hatamipour","doi":"10.6000/1929-5030.2015.04.01.1","DOIUrl":"https://doi.org/10.6000/1929-5030.2015.04.01.1","url":null,"abstract":"Lubricating base oil is commonly extracted from lube-oil cut, a petroleum cut, with the use of an aromatic solvent. Aromatic content of the final product is an important criterion specifying the product quality. The aromatic removal process to produce the lubricating oil should be carried out in a Liquid-Liquid extraction column. In a typical solvent extraction process, solvent to feed ratio, solvent and feed temperatures, agitation rate, and settling time could directly affect the yield of extraction. In the current study, the effect of agitation rate and settling time on the yield of extraction was studied. It was found that a settling time of 2hrs and an agitation rate of 430 RPM to be the optimum parameters of the extraction process.","PeriodicalId":15165,"journal":{"name":"Journal of Applied Solution Chemistry and Modeling","volume":"34 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2015-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88255742","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 : 2015-02-25DOI: 10.6000/1929-5030.2015.04.01.2
E. L. Ibarra-Montaño, Norma Rodríguez-Laguna, Aníbal Sánchez-Hernández, A. Rojas-Hernández
Acrylic, methacrylic and itaconic acids have Bronsted acidity given by carboxylic groups, and they are extensively used in polymerization for modification of several soft-mater materials. By this reason it is important to propose better characterization studies and alternatives to obtain more of their physicochemical properties. In this work the pK a values of these acids are obtained by adjusting NMR chemical shifts for hydrogen and carbon nuclei as a function of pH with program HYPNMR, and compared with those obtained by potentiometric and conductometric titrations.
{"title":"Determination of pKa Values for Acrylic, Methacrylic and Itaconic Acids by 1H and 13C NMR in Deuterated Water","authors":"E. L. Ibarra-Montaño, Norma Rodríguez-Laguna, Aníbal Sánchez-Hernández, A. Rojas-Hernández","doi":"10.6000/1929-5030.2015.04.01.2","DOIUrl":"https://doi.org/10.6000/1929-5030.2015.04.01.2","url":null,"abstract":"Acrylic, methacrylic and itaconic acids have Bronsted acidity given by carboxylic groups, and they are extensively used in polymerization for modification of several soft-mater materials. By this reason it is important to propose better characterization studies and alternatives to obtain more of their physicochemical properties. In this work the pK a values of these acids are obtained by adjusting NMR chemical shifts for hydrogen and carbon nuclei as a function of pH with program HYPNMR, and compared with those obtained by potentiometric and conductometric titrations.","PeriodicalId":15165,"journal":{"name":"Journal of Applied Solution Chemistry and Modeling","volume":"92 1","pages":"7-18"},"PeriodicalIF":0.0,"publicationDate":"2015-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77020124","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 : 2015-02-25DOI: 10.6000/1929-5030.2015.04.01.5
G. Dey
Nowadays, photocatalysis is being applied as a promising technique for decontamination, purification, deodorization, etc. of polluted air and wastewaters. This technique attempts also to generate renewable and non-polluting fuels utilizing various carbon and hydrogen sources. In this context, studies on photo-catalytic generation of H 2 using 0.1% w/v TiO 2 photo catalyst as a suspension in water was carried out using 350 nm light. This was explored further in presence of various metal ions such as Ag + , Cu 2+ , Fe 2+ , Au 3+ and V 5+ at different ambient such as air and CO 2 , in presence of a hole scavenger (2-propanol and formic acid). H 2 yields in CO 2 -purged systems as analyzed in GC-TCD were reasonably higher, and increased further when metal ions were added into the systems. Based on H 2 yields, HCOOH was found to be a more supportive hole scavenger as compared to 2-propanol in metal ions containing systems. Besides the formation of low to high concentrations of various gaseous products, nanoparticles of gold, silver and copper were also observed as photolysis products. This indicated that the presence of both reduced metal ions and their in-situ generated nanoparticles at various stages either in the free/unbound and/or associated with TiO 2 photocatalyst in aqueous systems, together play a significant role in enhancing the H 2 yields.
{"title":"Effects of Metal Ions on H2 Generation during Photolysis of Suspended TiO2 in Aqueous Systems","authors":"G. Dey","doi":"10.6000/1929-5030.2015.04.01.5","DOIUrl":"https://doi.org/10.6000/1929-5030.2015.04.01.5","url":null,"abstract":"Nowadays, photocatalysis is being applied as a promising technique for decontamination, purification, deodorization, etc. of polluted air and wastewaters. This technique attempts also to generate renewable and non-polluting fuels utilizing various carbon and hydrogen sources. In this context, studies on photo-catalytic generation of H 2 using 0.1% w/v TiO 2 photo catalyst as a suspension in water was carried out using 350 nm light. This was explored further in presence of various metal ions such as Ag + , Cu 2+ , Fe 2+ , Au 3+ and V 5+ at different ambient such as air and CO 2 , in presence of a hole scavenger (2-propanol and formic acid). H 2 yields in CO 2 -purged systems as analyzed in GC-TCD were reasonably higher, and increased further when metal ions were added into the systems. Based on H 2 yields, HCOOH was found to be a more supportive hole scavenger as compared to 2-propanol in metal ions containing systems. Besides the formation of low to high concentrations of various gaseous products, nanoparticles of gold, silver and copper were also observed as photolysis products. This indicated that the presence of both reduced metal ions and their in-situ generated nanoparticles at various stages either in the free/unbound and/or associated with TiO 2 photocatalyst in aqueous systems, together play a significant role in enhancing the H 2 yields.","PeriodicalId":15165,"journal":{"name":"Journal of Applied Solution Chemistry and Modeling","volume":"35 1","pages":"63-71"},"PeriodicalIF":0.0,"publicationDate":"2015-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80877007","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 : 2015-02-25DOI: 10.6000/1929-5030.2015.04.01.3
E. Starikov
The interrelationship between the conventional thermodynamics and energetics has been discussed in detail. A number of flavors has been considered in the field of energetics, with the conclusion that the actual difference among all of them is rather superficial. A need to reconsider the foundations of thermodynamics and statistical physics has been pointed out. Such a re-consideration ought to facilitate formulating thermodynamics at any level of matter organization: from the microscopic through nano- and mesoscopic to the macroscopic one.
{"title":"The Interrelationship between Thermodynamics and Energetics: The True Sense of Equilibrium Thermodynamics","authors":"E. Starikov","doi":"10.6000/1929-5030.2015.04.01.3","DOIUrl":"https://doi.org/10.6000/1929-5030.2015.04.01.3","url":null,"abstract":"The interrelationship between the conventional thermodynamics and energetics has been discussed in detail. A number of flavors has been considered in the field of energetics, with the conclusion that the actual difference among all of them is rather superficial. A need to reconsider the foundations of thermodynamics and statistical physics has been pointed out. Such a re-consideration ought to facilitate formulating thermodynamics at any level of matter organization: from the microscopic through nano- and mesoscopic to the macroscopic one.","PeriodicalId":15165,"journal":{"name":"Journal of Applied Solution Chemistry and Modeling","volume":"78 1","pages":"19-47"},"PeriodicalIF":0.0,"publicationDate":"2015-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74837389","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 : 2015-02-25DOI: 10.6000/1929-5030.2015.04.01.6
N. Mishra, K. Chaudhary, S. Awasthi
The absorption and steady state emission properties of a chemically synthesized chalcone, 3-(4-methoxyphenyl)-1-(4-(pyrrolidin-1-yl) phenyl) prop-2-en-1-one (MPPP) containing asymmetrical donor and acceptor groups has been investigated both experimentally and theoretically. The ground state, MPPP has a significant intramolecular charge transfer (ICT) character and a great sensitivity to the hydrogen bond donating ability of the medium as reflected from the absorption spectra in pure non polar, polar and neutral solvents. On the other hand, its excited singlet state exhibits high ICT characters as manifested by the drastic solvatochromic effects. These results are consistent with the data. The absorption spectra of the compound MPPP undergoes minor changes with increasing polarity of the solvents and the fluorescence spectra experiences a distinct bathochromic shifts in the both position and fluorescence quantum yields, increases reaching a maximum before decrease with increasing the solvent effects. The quantum yields decrease with increase in the solvent polarity. The magnitude of change in the dipole moment was also calculated using Austin Model 1 (AM1). These results suggest that the evidence about the intramolecular charge transfer in the emitting singlet state of this compound. The solvent dependence of quantum yields of MPPP was interpreted on the basis of positive and negative solvatokinetic as well as hydrogen bonding effects. Intramolecular charge (ICT) transfer took place from pyrrolidine nitrogen to α, β unsaturated carbonyl in the ground state.
实验和理论研究了化学合成的3-(4-甲氧基苯基)-1-(4-(吡咯烷-1-基)苯基)丙-2-烯-1-酮查尔酮(MPPP)含不对称供体和受体基团的吸收和稳态发射特性。从纯非极性、极性和中性溶剂的吸收光谱可以看出，基态下MPPP具有显著的分子内电荷转移(ICT)特性，对介质的氢键给予能力非常敏感。另一方面，其激发态单线态表现出高的ICT特性，表现为剧烈的溶剂致变色效应。这些结果与数据一致。化合物MPPP的吸收光谱随溶剂极性的增加变化不大，荧光光谱在位置和荧光量子产率上都有明显的显色位移，随溶剂效应的增加而增大，达到最大值，然后减小。量子产率随溶剂极性的增加而降低。利用Austin Model 1 (AM1)计算了偶极矩的变化幅度。这些结果表明，该化合物在发射单线态下分子内电荷转移的证据。根据正、负溶剂动力学和氢键效应解释了MPPP量子产率的溶剂依赖性。分子内电荷(ICT)从吡咯烷氮转移到基态的α， β不饱和羰基。
{"title":"Pyrrolidinyl Group as Charge Donor for the Excited State Intramolecular Chargetransferin 3-(4-methoxyphenyl)-1-(4-(pyrrolidin-1-yl) phenyl) Prop-2-en-1-one","authors":"N. Mishra, K. Chaudhary, S. Awasthi","doi":"10.6000/1929-5030.2015.04.01.6","DOIUrl":"https://doi.org/10.6000/1929-5030.2015.04.01.6","url":null,"abstract":"The absorption and steady state emission properties of a chemically synthesized chalcone, 3-(4-methoxyphenyl)-1-(4-(pyrrolidin-1-yl) phenyl) prop-2-en-1-one (MPPP) containing asymmetrical donor and acceptor groups has been investigated both experimentally and theoretically. The ground state, MPPP has a significant intramolecular charge transfer (ICT) character and a great sensitivity to the hydrogen bond donating ability of the medium as reflected from the absorption spectra in pure non polar, polar and neutral solvents. On the other hand, its excited singlet state exhibits high ICT characters as manifested by the drastic solvatochromic effects. These results are consistent with the data. The absorption spectra of the compound MPPP undergoes minor changes with increasing polarity of the solvents and the fluorescence spectra experiences a distinct bathochromic shifts in the both position and fluorescence quantum yields, increases reaching a maximum before decrease with increasing the solvent effects. The quantum yields decrease with increase in the solvent polarity. The magnitude of change in the dipole moment was also calculated using Austin Model 1 (AM1). These results suggest that the evidence about the intramolecular charge transfer in the emitting singlet state of this compound. The solvent dependence of quantum yields of MPPP was interpreted on the basis of positive and negative solvatokinetic as well as hydrogen bonding effects. Intramolecular charge (ICT) transfer took place from pyrrolidine nitrogen to α, β unsaturated carbonyl in the ground state.","PeriodicalId":15165,"journal":{"name":"Journal of Applied Solution Chemistry and Modeling","volume":"49 1","pages":"72-82"},"PeriodicalIF":0.0,"publicationDate":"2015-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77161197","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 : 2014-12-17DOI: 10.6000/1929-5030.2014.03.04.3
M. M. Silaev
Five reaction schemes are suggested for the initiated nonbranched-chain addition of free radicals to the multiple bonds of the unsaturated compounds. The proposed schemes include the reaction competing with chain propagation reactions through a reactive free radical. The chain evolution stage in these schemes involves three or four types of free radicals. One of them is relatively low-reactive and inhibits the chain process by shortening of the kinetic chain length. Based on the suggested schemes, nine rate equations (containing one to three parameters to be determined directly) are deduced using quasi-steady-state treatment. These equations provide good fits for the nonmonotonic (peaking) dependences of the formation rates of the molecular products (1:1 adducts) on the concentration of the unsaturated component in binary systems consisting of a saturated component (hydrocarbon, alcohol, etc.) and an unsaturated component (olefin, allyl alcohol, formaldehyde, or dioxygen). The unsaturated compound in these systems is both a reactant and an autoinhibitor generating low-reactive free radicals. A similar kinetic description is applicable to the nonbranched-chain process of the free-radical hydrogen oxidation, in which the oxygen with the increase of its concentration begins to act as an oxidation autoingibitor (or an antioxidant). The energetics of the key radical-molecule reactions is considered.
{"title":"The Radical-Chain Addition to Double Molecular Bonds by the Nonbranched-Chain Mechanism: Low-Reactive Free Radicals Shortening Kinetic Chains","authors":"M. M. Silaev","doi":"10.6000/1929-5030.2014.03.04.3","DOIUrl":"https://doi.org/10.6000/1929-5030.2014.03.04.3","url":null,"abstract":"Five reaction schemes are suggested for the initiated nonbranched-chain addition of free radicals to the multiple bonds of the unsaturated compounds. The proposed schemes include the reaction competing with chain propagation reactions through a reactive free radical. The chain evolution stage in these schemes involves three or four types of free radicals. One of them is relatively low-reactive and inhibits the chain process by shortening of the kinetic chain length. Based on the suggested schemes, nine rate equations (containing one to three parameters to be determined directly) are deduced using quasi-steady-state treatment. These equations provide good fits for the nonmonotonic (peaking) dependences of the formation rates of the molecular products (1:1 adducts) on the concentration of the unsaturated component in binary systems consisting of a saturated component (hydrocarbon, alcohol, etc.) and an unsaturated component (olefin, allyl alcohol, formaldehyde, or dioxygen). The unsaturated compound in these systems is both a reactant and an autoinhibitor generating low-reactive free radicals. A similar kinetic description is applicable to the nonbranched-chain process of the free-radical hydrogen oxidation, in which the oxygen with the increase of its concentration begins to act as an oxidation autoingibitor (or an antioxidant). The energetics of the key radical-molecule reactions is considered.","PeriodicalId":15165,"journal":{"name":"Journal of Applied Solution Chemistry and Modeling","volume":"3 1","pages":"202-222"},"PeriodicalIF":0.0,"publicationDate":"2014-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77721753","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 : 2014-12-17DOI: 10.6000/1929-5030.2014.03.04.2
Ke Zhang, D. Ma, Shi Li, Xinglong Chen
Many countries play an important role to carbon capture, utilization, and Storage (CCUS) to reduce emission. Geological storage is an important approach to cope with climate change. Live oil combined with saline aquifers and gas reservoirs are among the candidates for carbon dioxide (CO 2 ) sequestration, owing to their proven sealing capabilities and characterization. CO 2 mainly from power industrial was captured to improve oil recovery in some oilfields in China, and solubility is a key factor to evaluate storage ability of reservoir and saline aquifer. In this paper, CO 2 sequestration mechanisms in deplete reservoir and saline aquifer were explained. An experimental method to test solubility of CO 2 in emulsion system of liver oil and brine was developed. The experimental results showed that with the salinity increased, the solubility of CO 2 in reservoir oil increased slightly, and the solubility of CO 2 in brine decreased. Salinity has little impact on solubility of CO 2 in reservoir oil. With the pressure increased, the solubility of CO 2 in reservoir oil and brine both increased. Molecular diameter of reservoir oil and white oil have inverse proportion relationship with the solubility Research on solubility of CO 2 in brine and reservoir oil for depleted reservoir in China enabled us to better predict and deal with the challenges for rapid development of carbon storage.
{"title":"Solubility of CO2 in Brine and Reservoir Oil for Depleted Reservoirs in China","authors":"Ke Zhang, D. Ma, Shi Li, Xinglong Chen","doi":"10.6000/1929-5030.2014.03.04.2","DOIUrl":"https://doi.org/10.6000/1929-5030.2014.03.04.2","url":null,"abstract":"Many countries play an important role to carbon capture, utilization, and Storage (CCUS) to reduce emission. Geological storage is an important approach to cope with climate change. Live oil combined with saline aquifers and gas reservoirs are among the candidates for carbon dioxide (CO 2 ) sequestration, owing to their proven sealing capabilities and characterization. CO 2 mainly from power industrial was captured to improve oil recovery in some oilfields in China, and solubility is a key factor to evaluate storage ability of reservoir and saline aquifer. In this paper, CO 2 sequestration mechanisms in deplete reservoir and saline aquifer were explained. An experimental method to test solubility of CO 2 in emulsion system of liver oil and brine was developed. The experimental results showed that with the salinity increased, the solubility of CO 2 in reservoir oil increased slightly, and the solubility of CO 2 in brine decreased. Salinity has little impact on solubility of CO 2 in reservoir oil. With the pressure increased, the solubility of CO 2 in reservoir oil and brine both increased. Molecular diameter of reservoir oil and white oil have inverse proportion relationship with the solubility Research on solubility of CO 2 in brine and reservoir oil for depleted reservoir in China enabled us to better predict and deal with the challenges for rapid development of carbon storage.","PeriodicalId":15165,"journal":{"name":"Journal of Applied Solution Chemistry and Modeling","volume":"80 1","pages":"194-201"},"PeriodicalIF":0.0,"publicationDate":"2014-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80879258","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 : 2014-12-17DOI: 10.6000/1929-5030.2014.03.04.1
Y. Han, Laura D. Simionato, Romina G. Calvo, M. B. Mattei, A. Segall
In this work dissolution profiles of furosemide tablets of nine commercial products marketed in Argentine were evaluated. All brands fulfill the specifications of dissolution test of USP. Comparison of dissolution profiles were carried out by model-dependent and model independent approaches. Results obtained via model-dependent approach show a first order drug release mechanism especially for Brand I (reference) and Brand IV. Results obtained via model-independent approach show that there was not significant difference in Dissolution efficiency between the reference product and Brands II, III and IV and in Mean dissolution time between the reference product and Brands II, III, IV and V. Using fit factors, only Brands I and III were similar.
{"title":"Comparison of Dissolution Profiles of Furosemide Tablets Available in the Argentinian Market","authors":"Y. Han, Laura D. Simionato, Romina G. Calvo, M. B. Mattei, A. Segall","doi":"10.6000/1929-5030.2014.03.04.1","DOIUrl":"https://doi.org/10.6000/1929-5030.2014.03.04.1","url":null,"abstract":"In this work dissolution profiles of furosemide tablets of nine commercial products marketed in Argentine were evaluated. All brands fulfill the specifications of dissolution test of USP. Comparison of dissolution profiles were carried out by model-dependent and model independent approaches. Results obtained via model-dependent approach show a first order drug release mechanism especially for Brand I (reference) and Brand IV. Results obtained via model-independent approach show that there was not significant difference in Dissolution efficiency between the reference product and Brands II, III and IV and in Mean dissolution time between the reference product and Brands II, III, IV and V. Using fit factors, only Brands I and III were similar.","PeriodicalId":15165,"journal":{"name":"Journal of Applied Solution Chemistry and Modeling","volume":"6 1","pages":"186-193"},"PeriodicalIF":0.0,"publicationDate":"2014-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88868119","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 : 2014-12-17DOI: 10.6000/1929-5030.2014.03.04.5
M. M. Silaev
New reaction scheme is suggested for the initiated nonbranched-chain addition of free radicals to the multiple bond of the molecular oxygen. The scheme includes the reaction competing with chain propagation reactions through a reactive free radical. The chain evolution stage in this scheme involves a few of free radicals, one of which (tetraoxyl) is relatively low-reactive and inhibits the chain process by shortening of the kinetic chain length. Based on the proposed scheme rate equations (containing one to three parameters to be determined directly) are deduced using quasi-steady-state treatment. The kinetic description with use the obtained rate equations is applied to the I³-induced nonbranched-chain processes of the free-radical oxidation of liquid o -xylene at 373 K and hydrogen dissolved in water containing different amounts of oxygen at 296 K. In these processes the oxygen with the increase of its concentration begins to act as an oxidation autoingibitor (or an antioxidant), and the rate of peroxide formation as a function of the dissolved oxygen concentration has a maximum. The heat effects are compared for the overall reactions of dissociation of simple alkylperoxyl (exothermic) and alkoxyl (endothermic) free radicals in the gas phase. Possible nonchain pathways of the free-radical oxidation of hydrogen and the routes of ozone decay from the energetic standpoint via the reaction with the hydroxyl free radical in the upper atmosphere (including the addition yielding the hydrotetraoxyl free radical, which can be an intermediate in the sequence of conversions of biologically hazardous UV radiation energy) were examined. The energetics of the key radical-molecule reactions is considered.
{"title":"Nonbranched-Chain Oxidation: Low-Reactive RO•4 and HO•4 1:2 Adduct Radicals Shortening Kinetic Chains","authors":"M. M. Silaev","doi":"10.6000/1929-5030.2014.03.04.5","DOIUrl":"https://doi.org/10.6000/1929-5030.2014.03.04.5","url":null,"abstract":"New reaction scheme is suggested for the initiated nonbranched-chain addition of free radicals to the multiple bond of the molecular oxygen. The scheme includes the reaction competing with chain propagation reactions through a reactive free radical. The chain evolution stage in this scheme involves a few of free radicals, one of which (tetraoxyl) is relatively low-reactive and inhibits the chain process by shortening of the kinetic chain length. Based on the proposed scheme rate equations (containing one to three parameters to be determined directly) are deduced using quasi-steady-state treatment. The kinetic description with use the obtained rate equations is applied to the I³-induced nonbranched-chain processes of the free-radical oxidation of liquid o -xylene at 373 K and hydrogen dissolved in water containing different amounts of oxygen at 296 K. In these processes the oxygen with the increase of its concentration begins to act as an oxidation autoingibitor (or an antioxidant), and the rate of peroxide formation as a function of the dissolved oxygen concentration has a maximum. The heat effects are compared for the overall reactions of dissociation of simple alkylperoxyl (exothermic) and alkoxyl (endothermic) free radicals in the gas phase. Possible nonchain pathways of the free-radical oxidation of hydrogen and the routes of ozone decay from the energetic standpoint via the reaction with the hydroxyl free radical in the upper atmosphere (including the addition yielding the hydrotetraoxyl free radical, which can be an intermediate in the sequence of conversions of biologically hazardous UV radiation energy) were examined. The energetics of the key radical-molecule reactions is considered.","PeriodicalId":15165,"journal":{"name":"Journal of Applied Solution Chemistry and Modeling","volume":"56 1","pages":"231-241"},"PeriodicalIF":0.0,"publicationDate":"2014-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88414672","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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