Currently, there is a necessity for new technologies that are less harmful to the environment. Consumers have become increasingly demanding towards the quality of the processed products they consume as well as their environmental impact. Pulsed light (PL) technology is a green technology capable of maintaining food quality and safety without impairing nutritional value. PL has been used in the treatment of different food and its constituents. This mini-review aims to describe the basic principle of PL functioning as well as provide examples of the newest applications in the food industry.
{"title":"Pulsed light treatment in food","authors":"J. G. Aguilar","doi":"10.25082/CR.2019.02.007","DOIUrl":"https://doi.org/10.25082/CR.2019.02.007","url":null,"abstract":"Currently, there is a necessity for new technologies that are less harmful to the environment. Consumers have become increasingly demanding towards the quality of the processed products they consume as well as their environmental impact. Pulsed light (PL) technology is a green technology capable of maintaining food quality and safety without impairing nutritional value. PL has been used in the treatment of different food and its constituents. This mini-review aims to describe the basic principle of PL functioning as well as provide examples of the newest applications in the food industry.","PeriodicalId":66475,"journal":{"name":"化学报告(英文)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48586771","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 morphological stability of vesicles consisting of an amphiphilic poly(methacrylic acid)-block-poly(methyl methacrylate-random-methacrylic acid) diblock copolymer, PMAA-b-P(MMA-r-MAA), was investigated against the external stresses of pH, salt concentration and polyamine. The worm-like vesicles underwent a partial fusion at pH 12, however, they retained the worm-like shape at pH 13 due to electrostatic repulsion. On the other hand, the spherical vesicles were completely fused at pH 12, transformed into a sheet and did not retain their shape under the higher basic condition. Similarly, the worm-like vesicles retained their morphology in 0.1-mol% solutions of sodium chloride and sodium dodecyl sulfate, while the spherical vesicles caused division and fusion even at much lower concentrations. Poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) transformed the worm-like vesicle into a cleavable sheet, while it changed the spherical vesicles into a sheet without a specific form. It was found that this transformation based on the acid-base interaction between the carboxylic acid of the MAA block and the amine of the PDMAEMA was dependent on the molecular weight of the PDMAEMA. The short PDMAMA retarded the fusion of the vesicles.
{"title":"Morphological stability of worm-like vesicles consisting of amphiphilic diblock copolymer against external stress","authors":"E. Yoshida","doi":"10.25082/CR.2019.02.006","DOIUrl":"https://doi.org/10.25082/CR.2019.02.006","url":null,"abstract":"The morphological stability of vesicles consisting of an amphiphilic poly(methacrylic acid)-block-poly(methyl methacrylate-random-methacrylic acid) diblock copolymer, PMAA-b-P(MMA-r-MAA), was investigated against the external stresses of pH, salt concentration and polyamine. The worm-like vesicles underwent a partial fusion at pH 12, however, they retained the worm-like shape at pH 13 due to electrostatic repulsion. On the other hand, the spherical vesicles were completely fused at pH 12, transformed into a sheet and did not retain their shape under the higher basic condition. Similarly, the worm-like vesicles retained their morphology in 0.1-mol% solutions of sodium chloride and sodium dodecyl sulfate, while the spherical vesicles caused division and fusion even at much lower concentrations. Poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) transformed the worm-like vesicle into a cleavable sheet, while it changed the spherical vesicles into a sheet without a specific form. It was found that this transformation based on the acid-base interaction between the carboxylic acid of the MAA block and the amine of the PDMAEMA was dependent on the molecular weight of the PDMAEMA. The short PDMAMA retarded the fusion of the vesicles.","PeriodicalId":66475,"journal":{"name":"化学报告(英文)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44726941","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}
Yizhong Lu, Aniqa Sehrish, Romana Manzoor, K. Dong, Yuanyuan Jiang
Hydrogen peroxide (H2O2), first synthesized in 1818 through the acidification of barium peroxide (BaO2) with nitric acid, is a clear and colorless liquid which is entirely miscible with water and variety of organic solvents such as carboxylic esters. Anthraquinone process (an old production process of H2O2), a batch process carried out in large facilities is an energy demanding process that requires large facilities, and involves oxidation of anthraquinone molecules and sequential hydrogenation. Moreover, the direct synthesis method enables production in a continuous mode as well as it permits small scale, decentralized production. Many drawbacks associated with these processes such as, energetic inefficiency and inherent disadvantages have motivated researchers, industry and academia to find out alternative for synthesis of H2O2. Electrochemical route based on catalyst selectively reduce oxygen to hydrogen peroxide. O2 is cathodically reduced to produce H2O2 via 2-electron pathway or 4-electron pathway to get H2O. Electrolysis of water has an important place in storage and electrochemical energy conversion process where problem is to choose a sufficiently stable and active electrode for anodic oxygen evolution reaction. Most commonly used catalysts on the cathode are carbon based materials such as carbon black, carbon nanotubes, graphite, carbon sponge, and carbon fiber. In perspective of expanding demand of production and usage of hydrogen peroxide we review the past literature to summarize different production processes of H2O2. In this review paper, we mainly focus on electrochemical production of hydrogen peroxide along with other alternatives such as, anthraquinone method for industrial H2O2 production and direct synthesis process. We also review the catalytic activity, selectivity and stability for enhanced yield of H2O2. From revision of experimental and theoretical data from the past literature; we argue that successful implementation of electrochemical H2O2 production can be realized on the basis of stable, active and selective catalyst.
{"title":"Recent progress on electrochemical production of hydrogen peroxide","authors":"Yizhong Lu, Aniqa Sehrish, Romana Manzoor, K. Dong, Yuanyuan Jiang","doi":"10.25082/CR.2019.02.005","DOIUrl":"https://doi.org/10.25082/CR.2019.02.005","url":null,"abstract":"Hydrogen peroxide (H2O2), first synthesized in 1818 through the acidification of barium peroxide (BaO2) with nitric acid, is a clear and colorless liquid which is entirely miscible with water and variety of organic solvents such as carboxylic esters. Anthraquinone process (an old production process of H2O2), a batch process carried out in large facilities is an energy demanding process that requires large facilities, and involves oxidation of anthraquinone molecules and sequential hydrogenation. Moreover, the direct synthesis method enables production in a continuous mode as well as it permits small scale, decentralized production. Many drawbacks associated with these processes such as, energetic inefficiency and inherent disadvantages have motivated researchers, industry and academia to find out alternative for synthesis of H2O2. Electrochemical route based on catalyst selectively reduce oxygen to hydrogen peroxide. O2 is cathodically reduced to produce H2O2 via 2-electron pathway or 4-electron pathway to get H2O. Electrolysis of water has an important place in storage and electrochemical energy conversion process where problem is to choose a sufficiently stable and active electrode for anodic oxygen evolution reaction. Most commonly used catalysts on the cathode are carbon based materials such as carbon black, carbon nanotubes, graphite, carbon sponge, and carbon fiber. In perspective of expanding demand of production and usage of hydrogen peroxide we review the past literature to summarize different production processes of H2O2. In this review paper, we mainly focus on electrochemical production of hydrogen peroxide along with other alternatives such as, anthraquinone method for industrial H2O2 production and direct synthesis process. We also review the catalytic activity, selectivity and stability for enhanced yield of H2O2. From revision of experimental and theoretical data from the past literature; we argue that successful implementation of electrochemical H2O2 production can be realized on the basis of stable, active and selective catalyst.","PeriodicalId":66475,"journal":{"name":"化学报告(英文)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42553979","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}
J. Kupčík, P. Mikysek, D. Pokorná, R. Fajgar, P. Cuřínová, K. Soukup, J. Pola
Protection of various materials against hydration is of continuing interest to chemists and material scientists. We report on stabilization of porous surface of activated γ-alumina spheres (AAS) against hydration by an adhesive coat of nano-magnetite particles. The nano-Fe3O4-coated AAS were prepared in the ultrasound-agitated suspension of magnetite nanoparticles in heptane and were characterized by using X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), BET surface area analysis and X-ray photoelectron spectroscopy (XPS). It is deduced that nanoparticle-alumina bonding interaction in non-polar organic solvent is enhanced by van der Waals attractive forces and that sonication induces changes in alumina morphology only in regions of contact between alumina and magnetite nanoparticles. The coated AAS submerged in still water avoid hydration and remain permeable by small gaseous (N2) molecules, while those soaked in moving water lose part of their coat and undergo hydration. The pristine and the coated AAS were briefly compared for their ability to degrade model antibiotics by using LC-MS analysis. It is confirmed that the degradation of trimethoprim is more efficient on the coated AAS. Our results are challenging for further research of Coulombic interactions between nano-particles and appropriate solid supports.
{"title":"Magnetite nanoparticles coat around activated γ-alumina spheres: A case of novel protection of moisture-sensitive materials against hydration","authors":"J. Kupčík, P. Mikysek, D. Pokorná, R. Fajgar, P. Cuřínová, K. Soukup, J. Pola","doi":"10.25082/CR.2019.02.003","DOIUrl":"https://doi.org/10.25082/CR.2019.02.003","url":null,"abstract":"Protection of various materials against hydration is of continuing interest to chemists and material scientists. We report on stabilization of porous surface of activated γ-alumina spheres (AAS) against hydration by an adhesive coat of nano-magnetite particles. The nano-Fe3O4-coated AAS were prepared in the ultrasound-agitated suspension of magnetite nanoparticles in heptane and were characterized by using X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), BET surface area analysis and X-ray photoelectron spectroscopy (XPS). It is deduced that nanoparticle-alumina bonding interaction in non-polar organic solvent is enhanced by van der Waals attractive forces and that sonication induces changes in alumina morphology only in regions of contact between alumina and magnetite nanoparticles. The coated AAS submerged in still water avoid hydration and remain permeable by small gaseous (N2) molecules, while those soaked in moving water lose part of their coat and undergo hydration. The pristine and the coated AAS were briefly compared for their ability to degrade model antibiotics by using LC-MS analysis. It is confirmed that the degradation of trimethoprim is more efficient on the coated AAS. Our results are challenging for further research of Coulombic interactions between nano-particles and appropriate solid supports.","PeriodicalId":66475,"journal":{"name":"化学报告(英文)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43308587","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. Ratko, N. K. Luneva, V. V. Shevchuk, T. I. Ezovitova
Single-stage process of obtaining active carbon by thermal processing of plant raw materials (mixture of different types of wood sawdust), impregnated with the mixture of phosphoric acid, urea and nitric acid salts has been developed. Active influence of impregnates on the process of carbonization and formation of carbon residue has been formed. It is established that carbon residue obtained in the interval of heating 20°С–(500°С–700)°С, possesses high sorption activity to the vapors of organic compounds and has ion-exchange capacity. It has been showed that the value of carton residue depending on the impregnate used in the wood increases compared to the yield of non-treated initial raw materials by 3.1 times at 600°С and by 4.2 times at 700°С.
{"title":"Study of impregnated cellulose thermal treatment process and properties of obtained active carbon","authors":"A. Ratko, N. K. Luneva, V. V. Shevchuk, T. I. Ezovitova","doi":"10.25082/CR.2019.02.002","DOIUrl":"https://doi.org/10.25082/CR.2019.02.002","url":null,"abstract":"Single-stage process of obtaining active carbon by thermal processing of plant raw materials (mixture of different types of wood sawdust), impregnated with the mixture of phosphoric acid, urea and nitric acid salts has been developed. Active influence of impregnates on the process of carbonization and formation of carbon residue has been formed. It is established that carbon residue obtained in the interval of heating 20°С–(500°С–700)°С, possesses high sorption activity to the vapors of organic compounds and has ion-exchange capacity. It has been showed that the value of carton residue depending on the impregnate used in the wood increases compared to the yield of non-treated initial raw materials by 3.1 times at 600°С and by 4.2 times at 700°С.","PeriodicalId":66475,"journal":{"name":"化学报告(英文)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41901058","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}
Iron(III) loaded novolac-based network adsorbents 1 and 2 were studied for efficient removal of azo-dye pollutants from aqueous solutions. The adsorption behavior was evaluated by using methyl orange and orange-G as model azo dyes. The effect of parameters such as contact time and initial dye concentration on the adsorption of azo dyes was studied. The results showed that loading of Fe(III) onto the sorbent networks has noticeable effect on azo-dye sorption capacity. The adsorption equilibrium data were fitted to Freundlich isotherm model. Besides, the reusability of the dye loaded sorbents was investigated on adjusting pH of solutions.
{"title":"Azo-dye adsorption activity of iron(III) loaded novolac-based network sorbents","authors":"Samaresh Ghosh, M. Acharyya","doi":"10.25082/CR.2019.02.001","DOIUrl":"https://doi.org/10.25082/CR.2019.02.001","url":null,"abstract":"Iron(III) loaded novolac-based network adsorbents 1 and 2 were studied for efficient removal of azo-dye pollutants from aqueous solutions. The adsorption behavior was evaluated by using methyl orange and orange-G as model azo dyes. The effect of parameters such as contact time and initial dye concentration on the adsorption of azo dyes was studied. The results showed that loading of Fe(III) onto the sorbent networks has noticeable effect on azo-dye sorption capacity. The adsorption equilibrium data were fitted to Freundlich isotherm model. Besides, the reusability of the dye loaded sorbents was investigated on adjusting pH of solutions.","PeriodicalId":66475,"journal":{"name":"化学报告(英文)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46301443","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}
Kamchan Bamroongnok, Arunrat Khmahaengpol, S. Siri
Green synthesis of silver nanoparticles (AgNPs) mediated by plant extracts has drawn many research interests due to its simple, cost-effective, and eco-friendly approach. However, the extracts derived from phytoestrogenic plants that produce high phenolic-based compounds exhibiting the estrogenic activity have not yet investigated. This work reported the comparison of ethanolic extracts derived from phytoestogenic Dendrolobium lanceolatum and non-phytoestrogenic Raphanus sativus to facilitate the green synthesis of AgNPs. The total phenolic content and the reducing activity of D. lanceolatum extract were significantly higher than those of R. sativus extract. In addition, the formation of AgNPs could detect in the reaction using D. lanceolatum extract, but not R. sativus extract, as determined by the characteristic surface plasmon resonance peak of AgNPs at 416 nm. The synthesized AgNPs were spherical with an average diameter of 74.60±17.11 nm, which their face-centered cubic structure of silver was confirmed by X-ray diffraction analysis. Moreover, the synthesized AgNPs exhibited the antibacterial activity against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. The results of this work, thus, suggested the potential uses of phytoestrogenic plants as a good source of reducing and stabilizing agents for the production of AgNPs and other metallic nanoparticles.
{"title":"Comparison of ethanolic extracts of phytoestrogenic Dendrolobium lanceolatum and non-phytoestrogenic Raphanus sativus to mediate green syntheses of silver nanoparticles","authors":"Kamchan Bamroongnok, Arunrat Khmahaengpol, S. Siri","doi":"10.25082/CR.2019.01.005","DOIUrl":"https://doi.org/10.25082/CR.2019.01.005","url":null,"abstract":"Green synthesis of silver nanoparticles (AgNPs) mediated by plant extracts has drawn many research interests due to its simple, cost-effective, and eco-friendly approach. However, the extracts derived from phytoestrogenic plants that produce high phenolic-based compounds exhibiting the estrogenic activity have not yet investigated. This work reported the comparison of ethanolic extracts derived from phytoestogenic Dendrolobium lanceolatum and non-phytoestrogenic Raphanus sativus to facilitate the green synthesis of AgNPs. The total phenolic content and the reducing activity of D. lanceolatum extract were significantly higher than those of R. sativus extract. In addition, the formation of AgNPs could detect in the reaction using D. lanceolatum extract, but not R. sativus extract, as determined by the characteristic surface plasmon resonance peak of AgNPs at 416 nm. The synthesized AgNPs were spherical with an average diameter of 74.60±17.11 nm, which their face-centered cubic structure of silver was confirmed by X-ray diffraction analysis. Moreover, the synthesized AgNPs exhibited the antibacterial activity against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. The results of this work, thus, suggested the potential uses of phytoestrogenic plants as a good source of reducing and stabilizing agents for the production of AgNPs and other metallic nanoparticles.","PeriodicalId":66475,"journal":{"name":"化学报告(英文)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47706177","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}
Muhammad Isa Khan, Seemab Dildar, T. Iqbal, M. Shakil, M. Tahir, M. Zubair Rafique, Farooq Aziz, Sardar Bibi, M. Ijaz
We report novel gold nanoparticles by green method for different fruit extracts have gaining greater attention due to its versatile properties in different applications. In this article, GNPs synthesis is demonstrated successfully using fresh fruit extract of punica granatum and fragaria. The optical properties, morphology and elemental analysis of samples was done by using) different characterization techniques like SEM EDX and UV-Visible spectroscopy Biocompatibility of GNPs was determined by ALT, AST, ALP, Urea, Creatinine tests and also to investigate the effects of prepared GNPs on the kidney and liver functions. The GNPs prepared by fruit extract of punica granatum have more effects on the rabbits than GNPs prepared from fragaria but this effect normalizes after three days which shows its biocompatibility. To explore the photocatalytic activity of the GNPs the photocatalytic degradation of MB dye is also investigated. The results revealed that GNPs prepared through green synthesis route are found to be efficient enhancement in the degradation of MB dye in visible region due to large surface area. These particles were more active in catalytic reduction due to their high surface energy and in bio-medical applications as biocompatibility.
{"title":"In Vivo Study of Gold-Nanoparticles Using Different Extracts for kidney, liver function and Photocatalytic Application","authors":"Muhammad Isa Khan, Seemab Dildar, T. Iqbal, M. Shakil, M. Tahir, M. Zubair Rafique, Farooq Aziz, Sardar Bibi, M. Ijaz","doi":"10.25082/CR.2019.01.004","DOIUrl":"https://doi.org/10.25082/CR.2019.01.004","url":null,"abstract":"We report novel gold nanoparticles by green method for different fruit extracts have gaining greater attention due to its versatile properties in different applications. In this article, GNPs synthesis is demonstrated successfully using fresh fruit extract of punica granatum and fragaria. The optical properties, morphology and elemental analysis of samples was done by using) different characterization techniques like SEM EDX and UV-Visible spectroscopy Biocompatibility of GNPs was determined by ALT, AST, ALP, Urea, Creatinine tests and also to investigate the effects of prepared GNPs on the kidney and liver functions. The GNPs prepared by fruit extract of punica granatum have more effects on the rabbits than GNPs prepared from fragaria but this effect normalizes after three days which shows its biocompatibility. To explore the photocatalytic activity of the GNPs the photocatalytic degradation of MB dye is also investigated. The results revealed that GNPs prepared through green synthesis route are found to be efficient enhancement in the degradation of MB dye in visible region due to large surface area. These particles were more active in catalytic reduction due to their high surface energy and in bio-medical applications as biocompatibility.","PeriodicalId":66475,"journal":{"name":"化学报告(英文)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47273029","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}
Resultant gradient-information is introduced and applied to problems in chemical reactivity theory. This local measure of the structural information contained in (complex) wavefunctions of electronic states is related to the system overall kinetic energy combining the modulus (probability) and phase (current) contributions. The grand-ensemble representation of thermodynamic equilibria in open systems demonstrates the physical equivalence of the variational energetic and information principles. It is used and to relate the populational derivatives of ensemble-average functionals in both these representations, which represent reactivity criteria for diagnosing the charge-transfer (CT) phenomena. Their equivalence is demonstrated by using the in situ potential and hardness descriptors to predict the direction and optimum amount of CT. The virial theorem is generalized into thermodynamic quantities and used to extract the kinetic energy component from qualitative energy profiles in the bond-formation and (exo/endo)-ergic reactions. The role of electronic kinetic energy in such chemical processes is reexamined, the virial theorem implications for the Hammond postulate of reactivity theory are explored, and variations of the structural-information in chemical processes are addressed. The maximum thermodynamic information rule is formulated and “production” of the gradient- information in chemical reactions is addressed. The Hammond postulate is shown to be indexed by the geometric derivative of resultant gradient-information at transition-state complex.
{"title":"Resultant gradient information, kinetic energy and molecular virial theorem","authors":"R. Nalewajski","doi":"10.25082/CR.2019.01.003","DOIUrl":"https://doi.org/10.25082/CR.2019.01.003","url":null,"abstract":"Resultant gradient-information is introduced and applied to problems in chemical reactivity theory. This local measure of the structural information contained in (complex) wavefunctions of electronic states is related to the system overall kinetic energy combining the modulus (probability) and phase (current) contributions. The grand-ensemble representation of thermodynamic equilibria in open systems demonstrates the physical equivalence of the variational energetic and information principles. It is used and to relate the populational derivatives of ensemble-average functionals in both these representations, which represent reactivity criteria for diagnosing the charge-transfer (CT) phenomena. Their equivalence is demonstrated by using the in situ potential and hardness descriptors to predict the direction and optimum amount of CT. The virial theorem is generalized into thermodynamic quantities and used to extract the kinetic energy component from qualitative energy profiles in the bond-formation and (exo/endo)-ergic reactions. The role of electronic kinetic energy in such chemical processes is reexamined, the virial theorem implications for the Hammond postulate of reactivity theory are explored, and variations of the structural-information in chemical processes are addressed. The maximum thermodynamic information rule is formulated and “production” of the gradient- information in chemical reactions is addressed. The Hammond postulate is shown to be indexed by the geometric derivative of resultant gradient-information at transition-state complex.","PeriodicalId":66475,"journal":{"name":"化学报告(英文)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43971807","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}
An EPR study of paramagnetic centers formed by irradiation of polycrystalline L-α-anhydrous asparagine (L-Asn) was performed. The EPR spectra of gamma irradiated samples at room temperature, shown the presence of three types of paramagnetic centers. A possible mechanisms of formation for the three radical species is suggested, based also on literature data. The kinetics of the disappearance of radicals during thermal annealing indicated a complex mechanism.
{"title":"Kinetics of the thermal disappearance of radicals formed during the radiolysis of L-α-anhydrous asparagine","authors":"A. Neacsu, D. Gheorghe","doi":"10.25082/cr.2019.01.002","DOIUrl":"https://doi.org/10.25082/cr.2019.01.002","url":null,"abstract":"An EPR study of paramagnetic centers formed by irradiation of polycrystalline L-α-anhydrous asparagine (L-Asn) was performed. The EPR spectra of gamma irradiated samples at room temperature, shown the presence of three types of paramagnetic centers. A possible mechanisms of formation for the three radical species is suggested, based also on literature data. The kinetics of the disappearance of radicals during thermal annealing indicated a complex mechanism.","PeriodicalId":66475,"journal":{"name":"化学报告(英文)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41941444","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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