Pub Date : 2022-09-30DOI: 10.31489/2022ch3/3-22-23
Q. Berdinazarov, E. Khakberdiev, N. Normurodov, N. Ashurov
In this work, the influence of maleic anhydride grafted polypropylene (PP-g-MA) content on thermal and me-chanical properties of polypropylene (PP) composites with two types of clays, differing modifier density in the interlayer space, Cloisite15A and Cloisite20A, was studied. PP/clay composites were melt blended in presence of different content of PP-g-MA from 3, 6, 9, and 12 wt.%. It was found that Cloisite15A with a high density of the modifier promotes the formation of intercalated structures, while Cloisite20A with a low density of the modifier, predominantly exfoliated nanocomposites are formed. In the first case, the structure tends to become intercalated whilst composites with Cloisite20A favor the formation of predominantly exfo-liated structures. The formation of the nanocomposite is accompanied by a significant increase in thermal sta-bility (50 % weight loss is observed at temperatures of 360 °C and 430 °C for polypropylene and nanocompo-sites based on it, respectively). An analysis of the mechanical properties of nanocomposites generally indi-cates an increase in the elastic modulus by 15–20 %, and this effect is more pronounced for exfoliated struc-tures, the yield strength practically does not change, and the elongation at break decreases very noticeably.
{"title":"Mechanical and Thermal Degradation Properties of Isotactic Polypropylene Composites with Cloisite15A and Cloisite20A","authors":"Q. Berdinazarov, E. Khakberdiev, N. Normurodov, N. Ashurov","doi":"10.31489/2022ch3/3-22-23","DOIUrl":"https://doi.org/10.31489/2022ch3/3-22-23","url":null,"abstract":"In this work, the influence of maleic anhydride grafted polypropylene (PP-g-MA) content on thermal and me-chanical properties of polypropylene (PP) composites with two types of clays, differing modifier density in the interlayer space, Cloisite15A and Cloisite20A, was studied. PP/clay composites were melt blended in presence of different content of PP-g-MA from 3, 6, 9, and 12 wt.%. It was found that Cloisite15A with a high density of the modifier promotes the formation of intercalated structures, while Cloisite20A with a low density of the modifier, predominantly exfoliated nanocomposites are formed. In the first case, the structure tends to become intercalated whilst composites with Cloisite20A favor the formation of predominantly exfo-liated structures. The formation of the nanocomposite is accompanied by a significant increase in thermal sta-bility (50 % weight loss is observed at temperatures of 360 °C and 430 °C for polypropylene and nanocompo-sites based on it, respectively). An analysis of the mechanical properties of nanocomposites generally indi-cates an increase in the elastic modulus by 15–20 %, and this effect is more pronounced for exfoliated struc-tures, the yield strength practically does not change, and the elongation at break decreases very noticeably.","PeriodicalId":9421,"journal":{"name":"Bulletin of the Karaganda University. \"Chemistry\" series","volume":"193 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73949863","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 : 2022-03-30DOI: 10.31489/2022ch1/122-132
R. Shlyapov, S. Amerkhanova, А.S. Uali, T. B. Omarbekov, D. Belgibayeva
This work describes the formation of the ionic composition of the sorption layer during the concentration of copper-lead and pyrite-copper-zinc ore. The thermodynamics of the sorption layer of a sulfhydryl collector (sodium diisobutyl thiophosphate and potassium butyl xanthate) on the surface of chalcocite under various conditions of its oxidation has been studied using pH- and redoxometry. The nature of the change in the chalcocite electrode potential depending on the type of modifier and storage device, as well as on pH, has been experimentally clarified. The differences in the collective action of a one-component accumulator and a mixture of flotation reagents were revealed based on the thermodynamics analysis of the flotation process reactions. In addition, the optimal conditions for the flotation were determined. It was found that the quality of the concentrate is mainly influenced by two factors, such as the pulp redox potential and the pH of the medium. Mathematical equations of the optimal reagent and hydrodynamic enrichment regimes with the maximum dissolution of ore minerals in solutions of flotation reagents were modeled.
{"title":"Thermodynamics of chalcocite dissolving in solutions of flotation reagents","authors":"R. Shlyapov, S. Amerkhanova, А.S. Uali, T. B. Omarbekov, D. Belgibayeva","doi":"10.31489/2022ch1/122-132","DOIUrl":"https://doi.org/10.31489/2022ch1/122-132","url":null,"abstract":"This work describes the formation of the ionic composition of the sorption layer during the concentration of copper-lead and pyrite-copper-zinc ore. The thermodynamics of the sorption layer of a sulfhydryl collector (sodium diisobutyl thiophosphate and potassium butyl xanthate) on the surface of chalcocite under various conditions of its oxidation has been studied using pH- and redoxometry. The nature of the change in the chalcocite electrode potential depending on the type of modifier and storage device, as well as on pH, has been experimentally clarified. The differences in the collective action of a one-component accumulator and a mixture of flotation reagents were revealed based on the thermodynamics analysis of the flotation process reactions. In addition, the optimal conditions for the flotation were determined. It was found that the quality of the concentrate is mainly influenced by two factors, such as the pulp redox potential and the pH of the medium. Mathematical equations of the optimal reagent and hydrodynamic enrichment regimes with the maximum dissolution of ore minerals in solutions of flotation reagents were modeled.","PeriodicalId":9421,"journal":{"name":"Bulletin of the Karaganda University. \"Chemistry\" series","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78569404","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}
Aromatic diazonium salts are important building blocks in organic synthesis. The present review is concerned with such aromatic diazonium sulfonates as tosylates, dodecylbenzenesulfonates, triflates, camphorsulfonates, silica sulfates. The first part of the review provides information on the synthesis and application of these diazonium salts. It is shown that these diazonium compounds are easily synthesized by diazotization of anilines with sodium nitrite or alkyl nitrites in the presence of corresponding sulfonic acids with high yields. These diazonium salts have found wide application in the synthesis of aromatic azides, halides, triazenes, azo dyes, stilbenes, biaryls, etc. The second part of the article presents information on the comparison of the results of X-ray analysis, infrared spectroscopy and thermal analysis. The structure of diazonium sulfonate salts corresponds to the structure of classical diazonium salts (chlorides, sulfates, tetrafluoroborates). A significant difference between arenediazonium sulfonates and other diazonium salts is their explosion safety and stability in an individual form. Arenediazonium tosylates, triflates and camphorasulfonates are easily soluble both in water and in polar organic solvents. Arenediazonium dodecylbenzenesulfonates are soluble in nonpolar organic media. These features of sulfonate salts are paramount for distinguishing characteristics of the effect of the acid anion on the stability, solubility and reactivity of diazonium salts.
{"title":"Arenediazonium sulfonates: synthesis, comparison of structural and physicochemical properties","authors":"A. Kassanova, M.T. Yestayeva, M. O. Turtubayeva","doi":"10.31489/2022ch1/25-38","DOIUrl":"https://doi.org/10.31489/2022ch1/25-38","url":null,"abstract":"Aromatic diazonium salts are important building blocks in organic synthesis. The present review is concerned with such aromatic diazonium sulfonates as tosylates, dodecylbenzenesulfonates, triflates, camphorsulfonates, silica sulfates. The first part of the review provides information on the synthesis and application of these diazonium salts. It is shown that these diazonium compounds are easily synthesized by diazotization of anilines with sodium nitrite or alkyl nitrites in the presence of corresponding sulfonic acids with high yields. These diazonium salts have found wide application in the synthesis of aromatic azides, halides, triazenes, azo dyes, stilbenes, biaryls, etc. The second part of the article presents information on the comparison of the results of X-ray analysis, infrared spectroscopy and thermal analysis. The structure of diazonium sulfonate salts corresponds to the structure of classical diazonium salts (chlorides, sulfates, tetrafluoroborates). A significant difference between arenediazonium sulfonates and other diazonium salts is their explosion safety and stability in an individual form. Arenediazonium tosylates, triflates and camphorasulfonates are easily soluble both in water and in polar organic solvents. Arenediazonium dodecylbenzenesulfonates are soluble in nonpolar organic media. These features of sulfonate salts are paramount for distinguishing characteristics of the effect of the acid anion on the stability, solubility and reactivity of diazonium salts.","PeriodicalId":9421,"journal":{"name":"Bulletin of the Karaganda University. \"Chemistry\" series","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84685445","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}
R. Bhole, M. R. Swamy, R. Wavhale, C. Bonde, R. Chikhale
5-Fluorouracil, a primary molecule widely used in the treatment of various cancer stages, is rapidly metabolized to an inactive form, namely 5,6-dihydro-5-FU and various mutational changes in chemotherapy. We utilized a carbodiimide catalyst to form a conjugate with folic acid. As folic acid receptors are over-expressed in cancerous tissues, it increases the bioavailability of 5-FU. This work represents design and synthesis of the new vitamin-drug conjugate, possibly enhancing anticancer activity. 5-Fluorouracil has potent action on breast, colorectal, stomach, and skin cancer tissues. Folic acid aided in targeting FRα receptors of cancer cells selectively. 5-FUFA was subjected to spectral characterization to confirm successful conjugation. The molecular dynamics simulation was studied in the Schrodinger suite and validated by molecular trajectory in CPPTRAJ software. This conjugate was further studied for molecular modeling studies and the docking score of the conjugate represented a higher binding score than 5-FU, i.e., –8.0 Kcal/mol. The drug-receptor interaction was further validated using molecular dynamics simulation in the Schrodinger suite and molecular trajectory CPPTRAJ software for 100 ns. The molecular dynamics simulation results showed stability with slight conformational change at 25 ns from 2–4 Å
{"title":"Design of potential vitamin-drug conjugate for enhanced anticancer activity","authors":"R. Bhole, M. R. Swamy, R. Wavhale, C. Bonde, R. Chikhale","doi":"10.31489/2022ch1/6-14","DOIUrl":"https://doi.org/10.31489/2022ch1/6-14","url":null,"abstract":"5-Fluorouracil, a primary molecule widely used in the treatment of various cancer stages, is rapidly metabolized to an inactive form, namely 5,6-dihydro-5-FU and various mutational changes in chemotherapy. We utilized a carbodiimide catalyst to form a conjugate with folic acid. As folic acid receptors are over-expressed in cancerous tissues, it increases the bioavailability of 5-FU. This work represents design and synthesis of the new vitamin-drug conjugate, possibly enhancing anticancer activity. 5-Fluorouracil has potent action on breast, colorectal, stomach, and skin cancer tissues. Folic acid aided in targeting FRα receptors of cancer cells selectively. 5-FUFA was subjected to spectral characterization to confirm successful conjugation. The molecular dynamics simulation was studied in the Schrodinger suite and validated by molecular trajectory in CPPTRAJ software. This conjugate was further studied for molecular modeling studies and the docking score of the conjugate represented a higher binding score than 5-FU, i.e., –8.0 Kcal/mol. The drug-receptor interaction was further validated using molecular dynamics simulation in the Schrodinger suite and molecular trajectory CPPTRAJ software for 100 ns. The molecular dynamics simulation results showed stability with slight conformational change at 25 ns from 2–4 Å","PeriodicalId":9421,"journal":{"name":"Bulletin of the Karaganda University. \"Chemistry\" series","volume":"99 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90534200","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 : 2022-03-30DOI: 10.31489/2022ch1/113-121
A. Yuminova, E.A. Giniyatullina, L.M. Karieva, L. Chekanova
The physical-chemical properties of the industrial reagent “FM-1” have been investigated. These properties are necessary for evaluating its use as a collector in the processes of concentration of rare earth metal ions by ion flotation. “FM-1”, which is based on sodium salts of aminomethylenephosphonic acids, is used as a flocculant for oil production and purification of process waters from suspended particles and petroleum products. Protolytic equilibriums in aqueous solutions of the reagents were studied. The values of dissociation constants equaling pKa1 = 2.31±0.26 and pKa2 = 8.82±0.34 were determined spectrophotometrically. Surface tension of the reagent solutions at the solution-air interface was studied. The “FM-1” reagent was classified as a strong surface-active substance with the following parameters: Minimal surface tension σmin = 29 mN∙m-1, surface activity G = 0.031 N∙m2∙mol-1, critical concentration of micelle formation 1∙10–3 mol∙L-1. The regularities of the reagent’s interaction with lanthanum (III) ions were studied. A high degree of lanthanum ions’ precipitation (over 99.7 %) was observed over a rather wide interval of pH values (4.00–12.00); at this point, at pH ≥ 7.5, lanthanum hydroxide can co-precipitate. The formation of compounds in a solution with molar ratios [La]:[FM-1] = 1:1 and 1:2 was established by conductometric titration method. The findings of chemical analysis, FTIR spectroscopy and elemental analysis of the isolated precipitates suggested their structural formula. A possibility for the “FM-1” reagent to be used as a collector for the ion flotation of lanthanum (III)ions was shown
{"title":"Physical-chemical properties of FM-1 reagent as a potential collector for ion flotation of lanthanoids","authors":"A. Yuminova, E.A. Giniyatullina, L.M. Karieva, L. Chekanova","doi":"10.31489/2022ch1/113-121","DOIUrl":"https://doi.org/10.31489/2022ch1/113-121","url":null,"abstract":"The physical-chemical properties of the industrial reagent “FM-1” have been investigated. These properties are necessary for evaluating its use as a collector in the processes of concentration of rare earth metal ions by ion flotation. “FM-1”, which is based on sodium salts of aminomethylenephosphonic acids, is used as a flocculant for oil production and purification of process waters from suspended particles and petroleum products. Protolytic equilibriums in aqueous solutions of the reagents were studied. The values of dissociation constants equaling pKa1 = 2.31±0.26 and pKa2 = 8.82±0.34 were determined spectrophotometrically. Surface tension of the reagent solutions at the solution-air interface was studied. The “FM-1” reagent was classified as a strong surface-active substance with the following parameters: Minimal surface tension σmin = 29 mN∙m-1, surface activity G = 0.031 N∙m2∙mol-1, critical concentration of micelle formation 1∙10–3 mol∙L-1. The regularities of the reagent’s interaction with lanthanum (III) ions were studied. A high degree of lanthanum ions’ precipitation (over 99.7 %) was observed over a rather wide interval of pH values (4.00–12.00); at this point, at pH ≥ 7.5, lanthanum hydroxide can co-precipitate. The formation of compounds in a solution with molar ratios [La]:[FM-1] = 1:1 and 1:2 was established by conductometric titration method. The findings of chemical analysis, FTIR spectroscopy and elemental analysis of the isolated precipitates suggested their structural formula. A possibility for the “FM-1” reagent to be used as a collector for the ion flotation of lanthanum (III)ions was shown","PeriodicalId":9421,"journal":{"name":"Bulletin of the Karaganda University. \"Chemistry\" series","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90487136","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}
M. Burkeyev, M. Zhunissova, J. Plocek, A. Kazhmuratova, T. Zhumagalieva
The initial polypropylene glycol maleate has been obtained by the polycondensation reaction of maleic anhydride and propylene glycol. The molecular weight of the synthesized unsaturated polyester resin has been determined. The copolymers under study have been obtained by radical copolymerization of p-PGM. The possibility of synthesizing new polymers based on p-PGM with acrylic acid in the presence of a RAFT agent has been shown. The effect of RAFT agent concentration on the network density and product yield has been studied. It has been found that the yield of the cross-linked polymer decreases, its swelling capacity increases, and the yield of the linear polymer increases with an increase in the RAFT agent concentration. The effect of organic solvents, pH, and low-molecular-weight salts on the swelling degree of the synthesized copolymers has been investigated. The research results demonstrate that the susceptibility of polymer hydrogels to organic solvents and changes in pH, and low molecular weight salts, is affected by the amount of RAFT agent in the polymer. The synthesized objects have been characterized by infrared spectroscopy. Scanning electron microscopy has estimated the polymer surface morphology and pore sizes
{"title":"Properties of cross-linked copolymers of polypropylene glycol maleate with acrylic acid obtained at various concentrations of the RAFT agent","authors":"M. Burkeyev, M. Zhunissova, J. Plocek, A. Kazhmuratova, T. Zhumagalieva","doi":"10.31489/2022ch1/15-24","DOIUrl":"https://doi.org/10.31489/2022ch1/15-24","url":null,"abstract":"The initial polypropylene glycol maleate has been obtained by the polycondensation reaction of maleic anhydride and propylene glycol. The molecular weight of the synthesized unsaturated polyester resin has been determined. The copolymers under study have been obtained by radical copolymerization of p-PGM. The possibility of synthesizing new polymers based on p-PGM with acrylic acid in the presence of a RAFT agent has been shown. The effect of RAFT agent concentration on the network density and product yield has been studied. It has been found that the yield of the cross-linked polymer decreases, its swelling capacity increases, and the yield of the linear polymer increases with an increase in the RAFT agent concentration. The effect of organic solvents, pH, and low-molecular-weight salts on the swelling degree of the synthesized copolymers has been investigated. The research results demonstrate that the susceptibility of polymer hydrogels to organic solvents and changes in pH, and low molecular weight salts, is affected by the amount of RAFT agent in the polymer. The synthesized objects have been characterized by infrared spectroscopy. Scanning electron microscopy has estimated the polymer surface morphology and pore sizes","PeriodicalId":9421,"journal":{"name":"Bulletin of the Karaganda University. \"Chemistry\" series","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86924295","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}
T. Annavarapu, S. Kamepalli, S. kondala, V. Kotra, S. Challa, M. Rudrapal, Atul R. Bendale
Abnormal production of pro-inflammatory mediators and generation of reactive oxygen species (ROS) play a key role in the development and progression of various human disorders. The study aims to investigate the in vitro anti-inflammatory and antioxidant activity of 4-allyl pyrocatechol (4-APC) and its derivatives (APC-1 and APC-2) by albumin denaturation and 1,1-Diphenyl-2-picrylhydrazyl (DPPH) methods, respectively. Also, the test compounds are studied in silico for their inhibitory potential against the pro-inflammatory and oxidative markers (calpain, FAAH, and TNF-α) via molecular docking. The compounds have exhibited appreciable in vitro anti-inflammatory and antioxidant activities. The APC-2 compound has demonstrated significant anti-inflammatory and antioxidant activity (percentage inhibition = 69±0.76 and 77.05±0.92, respectively, at 100 μg/ml) compared to the standard drugs, aspirin and ascorbic acid (percentage inhibition = 82±0.83 and 92.35±0.75, respectively, at 100 μg/ml). The docking study has showed that APC-2 significantly inhibited calpain (PDB ID: 2R9C), FAAH (2WJ1) and TNF-α (2AZ5) inflammatory markers. The drug-likeness, bioactivities, ADME profile (pharmacokinetic) and toxicity properties have also been determined using online tools (Molinspiration, pkCSM, SwissADME, PreADMET). The test compounds have showed acceptable drug-likeness, bioactivity score, ADME and toxicity properties. Finally, we conclude that the 4-allylpyrocatechol and its derivatives can be used as lead molecules for their further development as therapeutically useful anti-inflammatory agents.
{"title":"Anti-inflammatory and antioxidant activities of 4-allylpyrocatechol and its derivatives with molecular docking and ADMET investigations","authors":"T. Annavarapu, S. Kamepalli, S. kondala, V. Kotra, S. Challa, M. Rudrapal, Atul R. Bendale","doi":"10.31489/2022ch1/50-59","DOIUrl":"https://doi.org/10.31489/2022ch1/50-59","url":null,"abstract":"Abnormal production of pro-inflammatory mediators and generation of reactive oxygen species (ROS) play a key role in the development and progression of various human disorders. The study aims to investigate the in vitro anti-inflammatory and antioxidant activity of 4-allyl pyrocatechol (4-APC) and its derivatives (APC-1 and APC-2) by albumin denaturation and 1,1-Diphenyl-2-picrylhydrazyl (DPPH) methods, respectively. Also, the test compounds are studied in silico for their inhibitory potential against the pro-inflammatory and oxidative markers (calpain, FAAH, and TNF-α) via molecular docking. The compounds have exhibited appreciable in vitro anti-inflammatory and antioxidant activities. The APC-2 compound has demonstrated significant anti-inflammatory and antioxidant activity (percentage inhibition = 69±0.76 and 77.05±0.92, respectively, at 100 μg/ml) compared to the standard drugs, aspirin and ascorbic acid (percentage inhibition = 82±0.83 and 92.35±0.75, respectively, at 100 μg/ml). The docking study has showed that APC-2 significantly inhibited calpain (PDB ID: 2R9C), FAAH (2WJ1) and TNF-α (2AZ5) inflammatory markers. The drug-likeness, bioactivities, ADME profile (pharmacokinetic) and toxicity properties have also been determined using online tools (Molinspiration, pkCSM, SwissADME, PreADMET). The test compounds have showed acceptable drug-likeness, bioactivity score, ADME and toxicity properties. Finally, we conclude that the 4-allylpyrocatechol and its derivatives can be used as lead molecules for their further development as therapeutically useful anti-inflammatory agents.","PeriodicalId":9421,"journal":{"name":"Bulletin of the Karaganda University. \"Chemistry\" series","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87444005","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}
S. Mendigalieva, D. Birimzhanova, I. Irgibaeva, N. Barashkov, Y. Sakhno
5-(Benzylidene)pyrimidine-2,4,6-triones with different substituents on the phenyl rings: 5-(4’-dimethyl-aminobenzylidene) barbituric acid and 5-(4’-methoxybenzylidene) barbituric acid were synthesized, and their spectral-luminescent properties were investigated. A decreasing fluorescence efficiency in the solid-state is general and is mainly attributed to the intermolecular vibronic interactions, which induce the nonradiative deactivation process. Whereas the isolated dye molecules are virtually non-luminescent in dilute solutions, they become highly emissive upon solution thickening or aggregation in poor solvents or in the solid-state, show an increase of luminescence intensity, the phenomenon of the aggregation-induced emission (AIE phenomenon). The development of efficient luminescent materials is a topic of great current interest. The emission color is changed from red (maximum at 630 nm) to green (maximum at 540 nm) by varying the substituent on the phenyl ring from dimethylamino to the methoxy group. Theoretical calculation shows that the dye molecules' aggregation-induced emission characteristics result from intermolecular interactions. Utilizing such features, the molecules can be employed as fluorescent probes for the detection of the ethanol content in aqueous solutions.
{"title":"Aggregation-induced emission of 5-(benzylidene)pyrimidine-2,4,6-triones","authors":"S. Mendigalieva, D. Birimzhanova, I. Irgibaeva, N. Barashkov, Y. Sakhno","doi":"10.31489/2022ch1/39-49","DOIUrl":"https://doi.org/10.31489/2022ch1/39-49","url":null,"abstract":"5-(Benzylidene)pyrimidine-2,4,6-triones with different substituents on the phenyl rings: 5-(4’-dimethyl-aminobenzylidene) barbituric acid and 5-(4’-methoxybenzylidene) barbituric acid were synthesized, and their spectral-luminescent properties were investigated. A decreasing fluorescence efficiency in the solid-state is general and is mainly attributed to the intermolecular vibronic interactions, which induce the nonradiative deactivation process. Whereas the isolated dye molecules are virtually non-luminescent in dilute solutions, they become highly emissive upon solution thickening or aggregation in poor solvents or in the solid-state, show an increase of luminescence intensity, the phenomenon of the aggregation-induced emission (AIE phenomenon). The development of efficient luminescent materials is a topic of great current interest. The emission color is changed from red (maximum at 630 nm) to green (maximum at 540 nm) by varying the substituent on the phenyl ring from dimethylamino to the methoxy group. Theoretical calculation shows that the dye molecules' aggregation-induced emission characteristics result from intermolecular interactions. Utilizing such features, the molecules can be employed as fluorescent probes for the detection of the ethanol content in aqueous solutions.","PeriodicalId":9421,"journal":{"name":"Bulletin of the Karaganda University. \"Chemistry\" series","volume":"49 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83268530","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}
K. Asgaonkar, S. Patil, T. Chitre, S. Wani, M.T. Singh
Tuberculosis (TB) is a leading cause of death worldwide from a single infectious agent, Mycobacterium tuberculosis (MTB), especially due to the development of resistant strains and its co-infections in HIV. Quantitative-structure activity relationship (QSAR) studies aid rapid drug discovery. In this work, 2D and 3D QSAR studies were carried out on a series of nitrobenzamide derivatives to design newer analogues for antitubercular activity. 2D QSAR was performed using MLR on a data set showing antitubercular activity. The 3D-QSAR studies were performed by kNN–MFA using simulated annealing variable selection method. Alignment of given set of molecules was carried out by the template-based alignment method and then was used to build the 3D-QSAR model. Robustness and predictive ability of the models were evaluated by using various traditional validating parameters. Different physiochemical, alignment-based, topological, electrostatic, and steric descriptors were generated, which indicated the key structural requirements for optimizing the pharmacophore for better antitubercular activity. For 2D QSAR, the best statistical model was generated using SA-MLR method (r2 = 0.892, q2 = 0.819) while 3D QSAR model was derived using the SA KNN method (q2 = 0.722). The positively contributing descriptors can be incorporated to design new chemical entities for future study.
{"title":"QSAR tool for optimization of nitrobenzamide pharmacophore for antitubercular activity","authors":"K. Asgaonkar, S. Patil, T. Chitre, S. Wani, M.T. Singh","doi":"10.31489/2022ch1/60-68","DOIUrl":"https://doi.org/10.31489/2022ch1/60-68","url":null,"abstract":"Tuberculosis (TB) is a leading cause of death worldwide from a single infectious agent, Mycobacterium tuberculosis (MTB), especially due to the development of resistant strains and its co-infections in HIV. Quantitative-structure activity relationship (QSAR) studies aid rapid drug discovery. In this work, 2D and 3D QSAR studies were carried out on a series of nitrobenzamide derivatives to design newer analogues for antitubercular activity. 2D QSAR was performed using MLR on a data set showing antitubercular activity. The 3D-QSAR studies were performed by kNN–MFA using simulated annealing variable selection method. Alignment of given set of molecules was carried out by the template-based alignment method and then was used to build the 3D-QSAR model. Robustness and predictive ability of the models were evaluated by using various traditional validating parameters. Different physiochemical, alignment-based, topological, electrostatic, and steric descriptors were generated, which indicated the key structural requirements for optimizing the pharmacophore for better antitubercular activity. For 2D QSAR, the best statistical model was generated using SA-MLR method (r2 = 0.892, q2 = 0.819) while 3D QSAR model was derived using the SA KNN method (q2 = 0.722). The positively contributing descriptors can be incorporated to design new chemical entities for future study.","PeriodicalId":9421,"journal":{"name":"Bulletin of the Karaganda University. \"Chemistry\" series","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77965958","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}
M. Sagyndikov, I. Salimgarayev, E. Ogay, R. Seright, S. Kudaibergenov
During a polymer flood, the field operator must be convinced that significant chemical investment is not compromised at the early stages of polymer injection. Further, dissolved oxygen in the viscous polymer solution must be controlled at a safe level, where viscosity loss will be insignificant. Under anaerobic conditions,the hydrolyzed polyacrylamide (HPAM) solution is stable even if iron ions are present in the process water. Thus, in the field operation, introduced oxygen and existing iron ions will cause an enormous viscosity decline. The geochemical calculation reveals that dissolved oxygen can rapidly deplete after entering Kalamkas formation. This paper confirms this prediction through a combination of laboratory measurements and field observations. This study is based on rheology measurements of polymer solutions and produced fluid from the offset production well associated with the Kalamkas oilfield in Western Kazakhstan. Comprehensive analysis confirms no viscosity loss at the surface facilities during polymer preparation and injection at a Pol- ymer Slicing Unit and significant viscosity loss at an Eductor-type unit caused by oxygen introduced during polymer solution preparation. However, even introduced high dissolved oxygen levels that degrade polymer at the surface can be rapidly depleted during contact with the formation, thereby promoting polymer chemical stability in the reservoir.
{"title":"Assessing polyacrylamide solution chemical stability during a polymer flood in the Kalamkas field, Western Kazakhstan","authors":"M. Sagyndikov, I. Salimgarayev, E. Ogay, R. Seright, S. Kudaibergenov","doi":"10.31489/2022ch1/99-112","DOIUrl":"https://doi.org/10.31489/2022ch1/99-112","url":null,"abstract":"During a polymer flood, the field operator must be convinced that significant chemical investment is not compromised at the early stages of polymer injection. Further, dissolved oxygen in the viscous polymer solution must be controlled at a safe level, where viscosity loss will be insignificant. Under anaerobic conditions,the hydrolyzed polyacrylamide (HPAM) solution is stable even if iron ions are present in the process water. Thus, in the field operation, introduced oxygen and existing iron ions will cause an enormous viscosity decline. The geochemical calculation reveals that dissolved oxygen can rapidly deplete after entering Kalamkas formation. This paper confirms this prediction through a combination of laboratory measurements and field observations. This study is based on rheology measurements of polymer solutions and produced fluid from the offset production well associated with the Kalamkas oilfield in Western Kazakhstan. Comprehensive analysis confirms no viscosity loss at the surface facilities during polymer preparation and injection at a Pol- ymer Slicing Unit and significant viscosity loss at an Eductor-type unit caused by oxygen introduced during polymer solution preparation. However, even introduced high dissolved oxygen levels that degrade polymer at the surface can be rapidly depleted during contact with the formation, thereby promoting polymer chemical stability in the reservoir.","PeriodicalId":9421,"journal":{"name":"Bulletin of the Karaganda University. \"Chemistry\" series","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75523821","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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