Pub Date : 2020-01-01DOI: 10.17721/1728-2209.2020.1(57).14
H. Yampolska, S. Kharchenko, A. Kozytskyi, A. Kyrylchuk, Z. Voitenko, O. Grygorenko
Macrocycles represent previously unexplored promising drug candidates, that can be useful for treating protein-protein interactions. Atropoisomerism is an inherent feature of the natural macrocyclic peptides that is significant for their activity and selectivity, and, therefore, should be introduced into newly synthesized macrocycles. Synthesis of the libraries of artificial macrocycles faces many challenges due to their structure and size. Herein we report on the preparation of a 16-membered macrocycle containing 1,2,3-triazole ring, spiro-piperidine, and phenyl moieties, as well as a chiral carbon atom. Our approach to the macrocycle was inspired by the "build/couple/pair" (B/C/P) strategy, a part of diversity-oriented synthesis methodology. We have employed readily accessible starting materials and robust synthetic procedures which allowed us to obtain the target macrocycle in a high yield. Standard methods of amide bond formation were used for the coupling of macrocycle building blocks. Click chemistry azide-alkyne cycloaddition was exploited at the final ring closure step. The assignment of signals in 1H and 13C NMR spectra of the macrocycle was performed using a series of 2D NMR techniques. The macrocycle displayed planar chirality, which, in a combination with a stereocenter with the known configuration, was sufficient to propose possible structures of diastereomers. The diastereomers could differ by the relative position of triazole ring. Their racemization could occur through a "rope skipping" motion involving the cyclic chain crossing the plane of 1,2,3-triazole ring. The supposed structures of diastereomers were corroborated by means of a various NMR spectroscopy techniques and DFT calculations. Analysis of the amide NH chemical shift temperature coefficients coupled with the data on optimized geometries obtained by DFT convincingly demonstrated that the intramolecular hydrogen bonds play a major role in stabilization of the diastereomer structures. According to the variable temperature NMR experiment, the interconversion of two diastereomers did not occur even at heating up to 70 °C.
{"title":"SYNTHESIS OF A 1,2,3-TRIAZOLE-CONTAINING MACROCYCLE BASED ON THE \"CLICK CHEMISTRY\" REACTION AND ANALYSIS OF ITS PLANAR CHIRALITY USING NMR AND DFT CALCULATIONS","authors":"H. Yampolska, S. Kharchenko, A. Kozytskyi, A. Kyrylchuk, Z. Voitenko, O. Grygorenko","doi":"10.17721/1728-2209.2020.1(57).14","DOIUrl":"https://doi.org/10.17721/1728-2209.2020.1(57).14","url":null,"abstract":"Macrocycles represent previously unexplored promising drug candidates, that can be useful for treating protein-protein interactions. Atropoisomerism is an inherent feature of the natural macrocyclic peptides that is significant for their activity and selectivity, and, therefore, should be introduced into newly synthesized macrocycles. Synthesis of the libraries of artificial macrocycles faces many challenges due to their structure and size. Herein we report on the preparation of a 16-membered macrocycle containing 1,2,3-triazole ring, spiro-piperidine, and phenyl moieties, as well as a chiral carbon atom. Our approach to the macrocycle was inspired by the \"build/couple/pair\" (B/C/P) strategy, a part of diversity-oriented synthesis methodology. We have employed readily accessible starting materials and robust synthetic procedures which allowed us to obtain the target macrocycle in a high yield. Standard methods of amide bond formation were used for the coupling of macrocycle building blocks. Click chemistry azide-alkyne cycloaddition was exploited at the final ring closure step. The assignment of signals in 1H and 13C NMR spectra of the macrocycle was performed using a series of 2D NMR techniques. The macrocycle displayed planar chirality, which, in a combination with a stereocenter with the known configuration, was sufficient to propose possible structures of diastereomers. The diastereomers could differ by the relative position of triazole ring. Their racemization could occur through a \"rope skipping\" motion involving the cyclic chain crossing the plane of 1,2,3-triazole ring. The supposed structures of diastereomers were corroborated by means of a various NMR spectroscopy techniques and DFT calculations. Analysis of the amide NH chemical shift temperature coefficients coupled with the data on optimized geometries obtained by DFT convincingly demonstrated that the intramolecular hydrogen bonds play a major role in stabilization of the diastereomer structures. According to the variable temperature NMR experiment, the interconversion of two diastereomers did not occur even at heating up to 70 °C.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78629469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.17721/1728-2209.2020.1(57).2
К. Klymyshyna, К. Тerebilenko, N. Strutynska, M. Slobodyanik
The efficient crystallization conditions for high temperature synthesis of sodium-cerium(III) orthophosphate from binary molten salts have been investigated in a light of influence of the inert reaction media addition. Taking into consideration NaF and Na2MoO4 as an addictives to a convention phosphate melt the crystallization regions of CePO4 and Na3Ce(PO4)2 have been identified by means of IR spectroscopy and powder X-Ray diffraction methods. The initial Na/P ratio in the melt has been shown to play the key role in pure Na3Ce(PO4)2 phase formation. The concentration of NaF has been chosen as 20–60 mol. % and MoO3 in a range of 30–60 mol. %, while the cerium(III) content has been maintained equal to 10 mol. %. Additional application of NaF or Na2MoO4 lowers the temperature from 1400 in comparison to Na4P2O7 flux to 1000°C and homogenization time from 12 to 1h., respectively. Thus, the optimal conditions for the high-temperature growth has been found to be Na/P = 1.67 and NaF content equal to 30–45% mol. in case of fluoride-containing systems, and Na/P> 4,00 with MoO3 content of 25–36% mol for a molybdate one. In case of both fluoride and molybdate addition the crystallization region of the target compound has been bordered by a wide area of CePO4 phase. Three crystallization regions has been estimated during crystallization process: CePO4, Na3Ce(PO4)2 and a wide field of their co-crystallization. With Na/P ratio in the binary melt there is a simultaneous change in the solids structure prepared. Thus, when CePO4 possesses highly condensed CeO8 polyhadra in the framework and crystallizes at lower Na/P ratio, Na3Ce(PO4)2 corresponds to isolated CeO8 moieties that are stabilized under higher Na/P values. Within the synthetic conditions investigated, the melts have shown to play a depolymerizing role for the phosphate chains found in the melt, leading to crystallization temperature lowering in initial melt. The approach proposed for the of Na3Ce(PO4)2 synthesis allows to expand the temperature range of its formation and to carry out its uniform doping with fluorescent activators to modify its characteristic spectrum for the needs of modern inorganic LEDs.
{"title":"THE ROLE OF COMBINED MOLTEN SALTS IN SODIUM-CERIUM (III) ORTHOPHOSPHATE CRYSTALLIZATION","authors":"К. Klymyshyna, К. Тerebilenko, N. Strutynska, M. Slobodyanik","doi":"10.17721/1728-2209.2020.1(57).2","DOIUrl":"https://doi.org/10.17721/1728-2209.2020.1(57).2","url":null,"abstract":"The efficient crystallization conditions for high temperature synthesis of sodium-cerium(III) orthophosphate from binary molten salts have been investigated in a light of influence of the inert reaction media addition. Taking into consideration NaF and Na2MoO4 as an addictives to a convention phosphate melt the crystallization regions of CePO4 and Na3Ce(PO4)2 have been identified by means of IR spectroscopy and powder X-Ray diffraction methods. The initial Na/P ratio in the melt has been shown to play the key role in pure Na3Ce(PO4)2 phase formation. The concentration of NaF has been chosen as 20–60 mol. % and MoO3 in a range of 30–60 mol. %, while the cerium(III) content has been maintained equal to 10 mol. %. Additional application of NaF or Na2MoO4 lowers the temperature from 1400 in comparison to Na4P2O7 flux to 1000°C and homogenization time from 12 to 1h., respectively. Thus, the optimal conditions for the high-temperature growth has been found to be Na/P = 1.67 and NaF content equal to 30–45% mol. in case of fluoride-containing systems, and Na/P> 4,00 with MoO3 content of 25–36% mol for a molybdate one. In case of both fluoride and molybdate addition the crystallization region of the target compound has been bordered by a wide area of CePO4 phase. Three crystallization regions has been estimated during crystallization process: CePO4, Na3Ce(PO4)2 and a wide field of their co-crystallization. With Na/P ratio in the binary melt there is a simultaneous change in the solids structure prepared. Thus, when CePO4 possesses highly condensed CeO8 polyhadra in the framework and crystallizes at lower Na/P ratio, Na3Ce(PO4)2 corresponds to isolated CeO8 moieties that are stabilized under higher Na/P values. Within the synthetic conditions investigated, the melts have shown to play a depolymerizing role for the phosphate chains found in the melt, leading to crystallization temperature lowering in initial melt. The approach proposed for the of Na3Ce(PO4)2 synthesis allows to expand the temperature range of its formation and to carry out its uniform doping with fluorescent activators to modify its characteristic spectrum for the needs of modern inorganic LEDs.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"126 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87887148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.17721/1728-2209.2020.1(57).8
T. Makarenko, R. Linnik, M. Malysheva, I. Mukha, N. Vityuk, O. Severinovskaya, A. Eremenko
Gold nanoparticles (Au NPs) are effective agents for early diagnostic and treatment of a variety of diseases, including cancer. However, initial components in the synthesis like surfactants, which are commonly used to stabilize nanoparticles, can produce toxic effects on living organisms. Thus, finding ways to reduce the toxicity of nanoscale preparations is an actual problem. In this regard the essential aminoacid tryptophan (Trp) is a promising reagent for the synthesis of Au NPs that can serve as a reducer of Au(ІІІ) ions and particle stabilizer. In this work, in order to increase the biocompatibility of the nanoscale system, the synthesis of gold nanoparticles was performed in the presence of Trp. The reaction between HAuCl4 and Trp proceeded in aqueous medium with neutral pH at different temperatures. Spectral characteristics of products formed in Au/Trp systems and were studied. In the absorption spectra the main band of Trp at 280 nm was shifted to 250 nm during the reaction; for all studied systems upon excitation of fluorescence with the wavelength of λex = 340 nm the maximum of the emission bands were observed at λem = 450 nm, while for initial tryptophan (λex = 280 nm) it was located at λex = 375nm. Mass spectra of Trp solution in positive mode contained the signal at 131 Da, that was characteristic for ionized indole moiety of amino acid. For supernatants of studied Au/Trp systems in positive mode signals of ionized fragments with masses of 118, 146 and 174 Da were observed. Based on the data it was revealed that amino acid oxidation proceeded through the formation of kynurenine or through the "kynurenine pathway", that corresponds to the metabolic conversion of amino acid in human organism and proves the biocompatibility of formed products.
{"title":"TRYPTOFAN TRANSFORMATION DURING THE REACTION WITH TETRACHLOROAURIC ACID","authors":"T. Makarenko, R. Linnik, M. Malysheva, I. Mukha, N. Vityuk, O. Severinovskaya, A. Eremenko","doi":"10.17721/1728-2209.2020.1(57).8","DOIUrl":"https://doi.org/10.17721/1728-2209.2020.1(57).8","url":null,"abstract":"Gold nanoparticles (Au NPs) are effective agents for early diagnostic and treatment of a variety of diseases, including cancer. However, initial components in the synthesis like surfactants, which are commonly used to stabilize nanoparticles, can produce toxic effects on living organisms. Thus, finding ways to reduce the toxicity of nanoscale preparations is an actual problem. In this regard the essential aminoacid tryptophan (Trp) is a promising reagent for the synthesis of Au NPs that can serve as a reducer of Au(ІІІ) ions and particle stabilizer. In this work, in order to increase the biocompatibility of the nanoscale system, the synthesis of gold nanoparticles was performed in the presence of Trp. The reaction between HAuCl4 and Trp proceeded in aqueous medium with neutral pH at different temperatures. Spectral characteristics of products formed in Au/Trp systems and were studied. In the absorption spectra the main band of Trp at 280 nm was shifted to 250 nm during the reaction; for all studied systems upon excitation of fluorescence with the wavelength of λex = 340 nm the maximum of the emission bands were observed at λem = 450 nm, while for initial tryptophan (λex = 280 nm) it was located at λex = 375nm. Mass spectra of Trp solution in positive mode contained the signal at 131 Da, that was characteristic for ionized indole moiety of amino acid. For supernatants of studied Au/Trp systems in positive mode signals of ionized fragments with masses of 118, 146 and 174 Da were observed. Based on the data it was revealed that amino acid oxidation proceeded through the formation of kynurenine or through the \"kynurenine pathway\", that corresponds to the metabolic conversion of amino acid in human organism and proves the biocompatibility of formed products.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75527713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.17721/1728-2209.2020.1(57).1
N. Strutynska, А. Spivak, R. Kuzmin, M. Slobodyanik
Complex oxide phosphates Na1.5Co1.5Fe1.5(PO4)3, Na1.75Co1.75Fe1.25(PO4)3, Na2Co2Fe(PO4)3 and Li0.25Na1.75Co2Fe(PO4)3, belonging to the alluaudite structural type (monoclinic system, space group C2/c) were synthesized by the melting method with further annealing of the homogenous glasses at a temperature 600°C. According to powder X-ray diffraction data the partial substitution of sodium cations by lithium cations in the initial phosphate matrix Na2Co2Fe(PO4)3 led to decreasing of lattice parameters for Li0.25Na1.75Co2Fe(PO4)3 (a = 11.7572(3) Å, b = 12.4528(4) Å, c = 6.4416(2) Å and β = 113.911(1)°). The FTIR-spectroscopy results confirmed the presence of PO4-tetrahedra in the composition of prepared phases. Modes in the regions of 400–600 cm-1 and 900–1000 cm–1 were assigned to symmetric and asymmetric stretching vibrations of phosphate tetrahedron in the alluaudite-type structure, respectively. The effect of partial substitution of sodium cations by lithium cations in the phosphate matrix Na2Co2Fe(PO4)3 as well as the decrease of sodium cations amounts in the alluauditerelated structure for the phases of Na1.5Co1.5Fe1.5(PO4)3 and Na1.75Co1.75Fe1.25(PO4)3 on the conductive properties of compounds were analyzed. It was found that increasing of sodium cations amount in the channels of the alluaudite-related structure leads to an increase of the specific conductivity from 0.011 Om-1m-1 for Na1.75Co1.75Fe1.25(PO4)3 to 0.15 Om–1m–1 for Na2Co2Fe(PO4)3 at a temperature of 550 °C. It was also found that partial substitution of sodium cations by lithium cations in the initial phosphate matrix Na2Co2Fe(PO4)3 no significant influence on conductivity of phase Li0.25Na1.75Co2Fe(PO4)3 (σ = 0.095 Оm–1m–1 at a temperature of 550 °C). In the case of phosphates Na1.75Co1.75Fe1.25(PO4)3 and Li0.25Na1.75Co2Fe(PO4)3 decreasing of conductive properties in the temperature ranges 190–250 °С and 550–590 °С, respectively are caused by contribution of different components in general conductivity. The synthesized phases can be used in the development of materials with conductive properties.
{"title":"SYNTHESIS, INVESTIGATION AND CONDUCTIVE PROPERTIES OF ALLUAUDITE-RELATED PHASES","authors":"N. Strutynska, А. Spivak, R. Kuzmin, M. Slobodyanik","doi":"10.17721/1728-2209.2020.1(57).1","DOIUrl":"https://doi.org/10.17721/1728-2209.2020.1(57).1","url":null,"abstract":"Complex oxide phosphates Na1.5Co1.5Fe1.5(PO4)3, Na1.75Co1.75Fe1.25(PO4)3, Na2Co2Fe(PO4)3 and Li0.25Na1.75Co2Fe(PO4)3, belonging to the alluaudite structural type (monoclinic system, space group C2/c) were synthesized by the melting method with further annealing of the homogenous glasses at a temperature 600°C. According to powder X-ray diffraction data the partial substitution of sodium cations by lithium cations in the initial phosphate matrix Na2Co2Fe(PO4)3 led to decreasing of lattice parameters for Li0.25Na1.75Co2Fe(PO4)3 (a = 11.7572(3) Å, b = 12.4528(4) Å, c = 6.4416(2) Å and β = 113.911(1)°). The FTIR-spectroscopy results confirmed the presence of PO4-tetrahedra in the composition of prepared phases. Modes in the regions of 400–600 cm-1 and 900–1000 cm–1 were assigned to symmetric and asymmetric stretching vibrations of phosphate tetrahedron in the alluaudite-type structure, respectively. The effect of partial substitution of sodium cations by lithium cations in the phosphate matrix Na2Co2Fe(PO4)3 as well as the decrease of sodium cations amounts in the alluauditerelated structure for the phases of Na1.5Co1.5Fe1.5(PO4)3 and Na1.75Co1.75Fe1.25(PO4)3 on the conductive properties of compounds were analyzed. It was found that increasing of sodium cations amount in the channels of the alluaudite-related structure leads to an increase of the specific conductivity from 0.011 Om-1m-1 for Na1.75Co1.75Fe1.25(PO4)3 to 0.15 Om–1m–1 for Na2Co2Fe(PO4)3 at a temperature of 550 °C. It was also found that partial substitution of sodium cations by lithium cations in the initial phosphate matrix Na2Co2Fe(PO4)3 no significant influence on conductivity of phase Li0.25Na1.75Co2Fe(PO4)3 (σ = 0.095 Оm–1m–1 at a temperature of 550 °C). In the case of phosphates Na1.75Co1.75Fe1.25(PO4)3 and Li0.25Na1.75Co2Fe(PO4)3 decreasing of conductive properties in the temperature ranges 190–250 °С and 550–590 °С, respectively are caused by contribution of different components in general conductivity. The synthesized phases can be used in the development of materials with conductive properties.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"75 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79273595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.17721/1728-2209.2020.1(57).13
V. Tkachuk, T. Lyubchuk, T. Tkachuk, O. Hordiyenko
2-(5-Oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)benzoic acid was synthesized using a new effective method – thermal heterocyclization of 3-(hydroxyimino)isoindolin-1-one, which occurs as a result of its interaction with 1,1'-carbonyldiimidazole (CDI) and subsequent base-promoted cycleopening of the obtained intermediate 3H,5H-[1,2,4]oxadiazolo[3,4-a]isoindole-3,5-dione. Direct cyclization of 3-(hydroxyimino)isoindolin-1-one by the reaction with diethyl carbonate in the presence of sodium ethylate in ethanol at room temperature and under heating was unsuccessful. The same result was observed when using triphosgene in the presence of triethylamine in dichloromethane. Treating 3-(hydroxyimino)isoindolin-1-one with methyl chloroformate gave 3-(((methoxycarbonyl)oxy)-imino)isoindolin-1-one which was thermally stable and was not cyclized into the desired acid by boiling in toluene and o-xylene for 24 hours. The reflux of the excess of CDI with 3-(hydroxyimino)isoindolin-1-one in anhydrous ethyl acetate and subsequent alkaline hydrolysis gave the desired 2-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)benzoic acid in a total yield of 90%. An attempt to stop the process at the stage of formation of the intermediate 3H,5H-[1,2,4]oxadiazolo[3,4-a]isoindole-3,5-dione by carrying out the reaction in the absence of a base failed. Its partial hydrolysis took place during the reaction, and especially at the stage of isolation, and as a result a mixture of 3H,5H-[1,2,4]oxadiazolo[3,4-a]isoindole-3,5-dione and 2-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)benzoic acid was formed in a ratio of about 2:3. The obtained substance after mixing with aqueousmethanolic NaOH solution and subsequent acidification with 1M HCl was quantitatively converted into the pure desired acid. The developed method allows the use of 3-(hydroxyimino)isoindolin-1-ones as convenient starting materials for the preparation of vic-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)aromatic acids and subsequently related compounds, in particular isomeric vic-carbamimidoyl(hetero)aromatic carboxylic acids, which cannot be obtained by other currently known methods. All the compounds obtained during the development of the method were studied by means of NMR spectroscopy.
{"title":"A DEVELOPMENT OF AN EFFECTIVE METHOD FOR THE SYNTHESIS OF 2-(5-OXO-4,5-DIHYDRO-1,2,4-OXADIAZOL-3-YL)BENZOIC ACID","authors":"V. Tkachuk, T. Lyubchuk, T. Tkachuk, O. Hordiyenko","doi":"10.17721/1728-2209.2020.1(57).13","DOIUrl":"https://doi.org/10.17721/1728-2209.2020.1(57).13","url":null,"abstract":"2-(5-Oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)benzoic acid was synthesized using a new effective method – thermal heterocyclization of 3-(hydroxyimino)isoindolin-1-one, which occurs as a result of its interaction with 1,1'-carbonyldiimidazole (CDI) and subsequent base-promoted cycleopening of the obtained intermediate 3H,5H-[1,2,4]oxadiazolo[3,4-a]isoindole-3,5-dione. Direct cyclization of 3-(hydroxyimino)isoindolin-1-one by the reaction with diethyl carbonate in the presence of sodium ethylate in ethanol at room temperature and under heating was unsuccessful. The same result was observed when using triphosgene in the presence of triethylamine in dichloromethane. Treating 3-(hydroxyimino)isoindolin-1-one with methyl chloroformate gave 3-(((methoxycarbonyl)oxy)-imino)isoindolin-1-one which was thermally stable and was not cyclized into the desired acid by boiling in toluene and o-xylene for 24 hours. The reflux of the excess of CDI with 3-(hydroxyimino)isoindolin-1-one in anhydrous ethyl acetate and subsequent alkaline hydrolysis gave the desired 2-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)benzoic acid in a total yield of 90%. An attempt to stop the process at the stage of formation of the intermediate 3H,5H-[1,2,4]oxadiazolo[3,4-a]isoindole-3,5-dione by carrying out the reaction in the absence of a base failed. Its partial hydrolysis took place during the reaction, and especially at the stage of isolation, and as a result a mixture of 3H,5H-[1,2,4]oxadiazolo[3,4-a]isoindole-3,5-dione and 2-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)benzoic acid was formed in a ratio of about 2:3. The obtained substance after mixing with aqueousmethanolic NaOH solution and subsequent acidification with 1M HCl was quantitatively converted into the pure desired acid. The developed method allows the use of 3-(hydroxyimino)isoindolin-1-ones as convenient starting materials for the preparation of vic-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)aromatic acids and subsequently related compounds, in particular isomeric vic-carbamimidoyl(hetero)aromatic carboxylic acids, which cannot be obtained by other currently known methods. All the compounds obtained during the development of the method were studied by means of NMR spectroscopy.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75365278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.17721/1728-2209.2020.1(57).7
V. Starova
One of the primary tasks in the development of amine hardeners for adhesive and epoxy resins is the control of amino group quantities in their composition. The main parameter that indicates the rate of the polymerization reaction and characterizes the quality of the hardener is the amine number. It is determined by the number of primary and secondary amino groups contained in the hardener molecule, because these functional groups are involved in reactions with epoxy resins. The most common methods of analysis of amine hardeners are mainly based on titration in organic solvents and require a procedure of derivatization of primary and secondary amino groups using formaldehyde and acetic anhydride. The search for a simple, cheap and environmentally friendly alternative to such titrimetric methods is still ongoing. In this paper on the example of industrial samples of polyamide PO-300, polyethylene polyamine (PEPA) and diethylenetriamine (DETA) shows the prospects of using the method of pH-metric titration in water-micellar medium of sodium dodecylsulfate (SDS) to determine the content of primary and secondary amino groups in the adhesive hardeners. According to the developed techniques, working solutions of PO-300, PEPA and DETA were prepared by dissolving their exact mass in 20 ml of 2.0 M SDS solution. The values of PO-300, PEPA and DETA samples were 0.1040 g, 0.0225 g and 0,0200 g, respectively. Titration of the obtained solutions was performed with 0.05 M HCl solution. The percentage of primary amino groups, calculated on the basis of the obtained differential titration curves, is equal to 5,56% for PO-300, 23,6% for PEPA and 31,6% for DETA. The content of secondary amino groups in PO-300, PEPA and DETA samples is 3,03%, 15,0% and 19,6%. Founded amine number for PO-300, PEPA and DETA is well correlated with data declared by the manufacturer and equals to 302, 1381 and 1890, respectively. Unfortunately, it was not possible to establish the presence and quantity of tertiary amino groups in the samples of adhesive hardeners by this technique. The effect of cationic surfactant cetylpyridinium chloride, nonionic Triton X-100 and anionic surfactant SDS on the value of the pH jump of diethylenetriamine (DETA) was also studied. It was found that anionic SDS has the greatest differentiating effect on the acid-base properties of amino groups DETA in comparison with other studied surfactants. At that, the primary amino groups are titrated in the first place.
在粘合剂和环氧树脂用胺类硬化剂的开发中，主要任务之一是控制其组成中氨基的数量。表明聚合反应速度和表征硬化剂质量的主要参数是胺数。它是由硬化剂分子中含有的初级和次级氨基的数量决定的，因为这些官能团与环氧树脂发生反应。胺类硬化剂最常用的分析方法主要是在有机溶剂中滴定，需要用甲醛和乙酸酐衍生出伯胺和仲胺基。寻找一种简单、廉价和环保的方法来替代这种滴定方法仍在进行中。本文以聚酰胺PO-300、聚乙烯多胺(PEPA)和二乙烯三胺(DETA)的工业样品为例，介绍了在十二烷基硫酸钠(SDS)水胶束介质中ph滴定法测定胶粘剂中叔胺和仲胺含量的前景。根据所开发的技术，将PO-300、PEPA和DETA的准确质量溶于20 ml 2.0 M SDS溶液中制备工作液。PO-300、PEPA和DETA样品的含量分别为0.1040 g、0.0225 g和0.0200 g。所得溶液用0.05 M盐酸溶液滴定。根据所得的差分滴定曲线计算，PO-300的一级氨基百分比为5.56%，PEPA为23.6%，DETA为31.6%。PO-300、PEPA和DETA样品中二级氨基的含量分别为3.03%、15.0%和19.6%。PO-300的建立胺数、PEPA和DETA与制造商申报的数据有很好的相关性，分别为302、1381和1890。不幸的是，它是不可能建立的存在和数量的叔氨基基在粘接剂的硬化剂样品通过这种技术。研究了阳离子表面活性剂十六烷基氯吡啶、非离子表面活性剂Triton X-100和阴离子表面活性剂SDS对二乙烯三胺(DETA) pH跳变值的影响。与其他表面活性剂相比，阴离子SDS对氨基乙酸的酸碱性质有最大的区分作用。这样，初级氨基首先被滴定。
{"title":"ANALYSIS OF AMINE HARDENERS FOR ADHESIVE USING pH-METRIC TITRATION IN MICELLAR MEDIA OF SODIUM DODECYLSULFATE","authors":"V. Starova","doi":"10.17721/1728-2209.2020.1(57).7","DOIUrl":"https://doi.org/10.17721/1728-2209.2020.1(57).7","url":null,"abstract":"One of the primary tasks in the development of amine hardeners for adhesive and epoxy resins is the control of amino group quantities in their composition. The main parameter that indicates the rate of the polymerization reaction and characterizes the quality of the hardener is the amine number. It is determined by the number of primary and secondary amino groups contained in the hardener molecule, because these functional groups are involved in reactions with epoxy resins. The most common methods of analysis of amine hardeners are mainly based on titration in organic solvents and require a procedure of derivatization of primary and secondary amino groups using formaldehyde and acetic anhydride. The search for a simple, cheap and environmentally friendly alternative to such titrimetric methods is still ongoing. In this paper on the example of industrial samples of polyamide PO-300, polyethylene polyamine (PEPA) and diethylenetriamine (DETA) shows the prospects of using the method of pH-metric titration in water-micellar medium of sodium dodecylsulfate (SDS) to determine the content of primary and secondary amino groups in the adhesive hardeners. According to the developed techniques, working solutions of PO-300, PEPA and DETA were prepared by dissolving their exact mass in 20 ml of 2.0 M SDS solution. The values of PO-300, PEPA and DETA samples were 0.1040 g, 0.0225 g and 0,0200 g, respectively. Titration of the obtained solutions was performed with 0.05 M HCl solution. The percentage of primary amino groups, calculated on the basis of the obtained differential titration curves, is equal to 5,56% for PO-300, 23,6% for PEPA and 31,6% for DETA. The content of secondary amino groups in PO-300, PEPA and DETA samples is 3,03%, 15,0% and 19,6%. Founded amine number for PO-300, PEPA and DETA is well correlated with data declared by the manufacturer and equals to 302, 1381 and 1890, respectively. Unfortunately, it was not possible to establish the presence and quantity of tertiary amino groups in the samples of adhesive hardeners by this technique. The effect of cationic surfactant cetylpyridinium chloride, nonionic Triton X-100 and anionic surfactant SDS on the value of the pH jump of diethylenetriamine (DETA) was also studied. It was found that anionic SDS has the greatest differentiating effect on the acid-base properties of amino groups DETA in comparison with other studied surfactants. At that, the primary amino groups are titrated in the first place.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"232 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72555490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.17721/1728-2209.2020.1(57).3
S. Nedilko, O. Dzyazko, T. Voitenko, M. Zelenko, I. Fesych, O. Ivanov
High-temperature superconducting compounds based on rare-earth elements with a perovskite-like structure play an important role in the creation of modern functional materials with special magnetic, superconducting and electrophysical properties. The potential of high-temperature superconducting compounds is widely used in microelectronics, medicine, transport, telecommunications technology, energy and more. Increased functionality, performance and reliability are the driving force for the production, research and application of this class of inorganic functional materials. Solid solutions of the type NdBa2–xNdxCu3O7–δ, are structural analogues of HTSC cuprate YBa2Cu3Oy (Y123). The study of the substitution of Ba2+ atoms for Nd3+ is important for obtaining new promising materials with various electrophysical and magnetic properties, as well as improving the characteristics of existing substances. Compounds of the composition NdBa2-xNdxCu3O7–δ, where x = 0–0.9 were synthesized sol-gel method. The parameters of the crystallattice and the transition temperature to the superconducting state for the synthesized compounds are calculated. The dependence of the parameters and the type of symmetry of the crystallattice of systems on the degree of substitution of x is investigated. It was found that the samples, sol-gel method are single-phase. The unsubstituted sample of NdBa2-xNdxCu3O7–δ, is single-phase, has an orthorhombic syngony of o-Nd123 and a space group Pmmm. Within creasing degree of substitution x in solid solutions of NdBa2–xNdxCu3O7–δ, where x = 0–0.9, there is a transition from the orthorhombic to tetragonal phase (space symmetry group P4/mmm).
{"title":"NEODYMIUM CUPRATE SOLID SOLUTION SUBSTITUTIONS OF SUBMICRON DISPERSION","authors":"S. Nedilko, O. Dzyazko, T. Voitenko, M. Zelenko, I. Fesych, O. Ivanov","doi":"10.17721/1728-2209.2020.1(57).3","DOIUrl":"https://doi.org/10.17721/1728-2209.2020.1(57).3","url":null,"abstract":"High-temperature superconducting compounds based on rare-earth elements with a perovskite-like structure play an important role in the creation of modern functional materials with special magnetic, superconducting and electrophysical properties. The potential of high-temperature superconducting compounds is widely used in microelectronics, medicine, transport, telecommunications technology, energy and more. Increased functionality, performance and reliability are the driving force for the production, research and application of this class of inorganic functional materials. Solid solutions of the type NdBa2–xNdxCu3O7–δ, are structural analogues of HTSC cuprate YBa2Cu3Oy (Y123). The study of the substitution of Ba2+ atoms for Nd3+ is important for obtaining new promising materials with various electrophysical and magnetic properties, as well as improving the characteristics of existing substances. Compounds of the composition NdBa2-xNdxCu3O7–δ, where x = 0–0.9 were synthesized sol-gel method. The parameters of the crystallattice and the transition temperature to the superconducting state for the synthesized compounds are calculated. The dependence of the parameters and the type of symmetry of the crystallattice of systems on the degree of substitution of x is investigated. It was found that the samples, sol-gel method are single-phase. The unsubstituted sample of NdBa2-xNdxCu3O7–δ, is single-phase, has an orthorhombic syngony of o-Nd123 and a space group Pmmm. Within creasing degree of substitution x in solid solutions of NdBa2–xNdxCu3O7–δ, where x = 0–0.9, there is a transition from the orthorhombic to tetragonal phase (space symmetry group P4/mmm).","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"56 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83877129","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 : 2019-01-01DOI: 10.17721/1728-2209.2019.1(56).7
M. Davidenko, I. Davidenko, V. Kravchenko, O. Mokrinska, V. Pavlov, S. Studzinsky, V. Tarasenko, L. Tonkopiyeva
The films of polymeric composites containing monomers of azobenzene dyes or azobenzene lateral groups chemically bonded to the main polymer chain demonstrate photoactive properties, and can be used in electrooptical light modulators and in recording media (RM) for polarization holography. Photoinduced optical anisotropy (PIA) appears under influence of linearly polarized light caused by the processes of trans-cis-izomerization of the azobenzene groups. This process is determining for application of the considered materials as RM for polarization holography. The films of polymeric polarization sensitive media based on a copolymer of styrene with nonyl methacrylate doped with azobenzene-type dyes with different electron-acceptor substituents are obtained in this work. In the films of copolymer the holograms of the plane wave front were registered for parallel and orthogonal orientations of polarization vectors of the object and reference light beams. Their photoelectrophysical, in particular photodielectric, and information properties are investigated. It was established, that when the mutual orientation of the recording beams changes from the orthogonal to parallel orientation the diffraction efficiency of the holograms increases in the case of using azo dye with the maximum number of auxochromic substituents in the molecule. The effect of the diffraction efficiency dependence on the chromophores structure is connected with the deepening of dye color. The photo-induced optical anisotropy in the films appears due to a change of the concentration ratio of trans- and cis-isomers of azobenzene dye fragments. This conclusion is confirmed by the photodielectric measurements data, namely, by the negative sign of the photodielectric effect, observed experimentally in the investigated thin film structures. It was shown, that investigated compositions can be used as information media for polarization holography.
{"title":"THE EFFECT OF THE SUBSTITUENT NATURE IN THE AZOBENZENE CHROMOPHORES ON DIFFRACTION EFFICIENCY OF POLARIZATION HOLOGRAMS","authors":"M. Davidenko, I. Davidenko, V. Kravchenko, O. Mokrinska, V. Pavlov, S. Studzinsky, V. Tarasenko, L. Tonkopiyeva","doi":"10.17721/1728-2209.2019.1(56).7","DOIUrl":"https://doi.org/10.17721/1728-2209.2019.1(56).7","url":null,"abstract":"The films of polymeric composites containing monomers of azobenzene dyes or azobenzene lateral groups chemically bonded to the main polymer chain demonstrate photoactive properties, and can be used in electrooptical light modulators and in recording media (RM) for polarization holography. Photoinduced optical anisotropy (PIA) appears under influence of linearly polarized light caused by the processes of trans-cis-izomerization of the azobenzene groups. This process is determining for application of the considered materials as RM for polarization holography. The films of polymeric polarization sensitive media based on a copolymer of styrene with nonyl methacrylate doped with azobenzene-type dyes with different electron-acceptor substituents are obtained in this work. In the films of copolymer the holograms of the plane wave front were registered for parallel and orthogonal orientations of polarization vectors of the object and reference light beams. Their photoelectrophysical, in particular photodielectric, and information properties are investigated. It was established, that when the mutual orientation of the recording beams changes from the orthogonal to parallel orientation the diffraction efficiency of the holograms increases in the case of using azo dye with the maximum number of auxochromic substituents in the molecule. The effect of the diffraction efficiency dependence on the chromophores structure is connected with the deepening of dye color. The photo-induced optical anisotropy in the films appears due to a change of the concentration ratio of trans- and cis-isomers of azobenzene dye fragments. This conclusion is confirmed by the photodielectric measurements data, namely, by the negative sign of the photodielectric effect, observed experimentally in the investigated thin film structures. It was shown, that investigated compositions can be used as information media for polarization holography.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88533972","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 : 2019-01-01DOI: 10.17721/1728-2209.2019.1(56).5
S. Shilin, Z. Voitenko, M. Nechai
This paper reports on the synthesis of new derivatives of ε-aminocaproic and γ-aminobutyric acid modified with a pyridin-2-yl substituent at the ω-position of the main chain. The hemostatic activity of both ε-aminocaproic acid itself and its various synthetic analogues is widely known. Likewise, numerous γ-aminobutyric acid derivatives are strong neurotransmitters extensively used in the treatment of the nervous system disorders. No less popular are biologically active substances containing a pyridine or piperidine fragment; among which there are antibiotics, antimalarial, anti-sclerotic and antiallergic drugs, as well as anti-depressants and analgesics. Therefore, the introduction of the pyridine fragment into the amino acid structures is interesting in terms of their potential biological activity investigation. So, a method for the synthesis of 5-amino-5-(pyridin-2-yl)pentanoic and 6-amino-6-(pyridin-2-yl)hexanoic acid has been developed by us. The proposed scheme is based on the available reagents using. The key stage is the Schmidt rearrangement of 2-(pyridin-2-yl)cyclopentanone and 2-(pyridin-2-yl)cyclohexanone, previously synthesized from pyridine N-oxide and cycloalkenyl morpholinide. For synthesized pyridine substituted cycloalkanones according to NMR spectroscopy, the presence of keto-enol tautomerism was established. As a result of Schmidt rearrangement, lactams (2-(pyridin-2-yl)piperidone and 2-(pyridin-2-yl)azepanone) are formed, and the last ones had been hydrolyzed in an acidic medium to open the lactam cycle. Thus, 5-amino-5-(pyridin-2-yl)pentanoic and 6-amino-6-(pyridin-2-yl)hexanoic acid were isolated as hydrochlorides and the hydrochlorides were converted to the zwitterion form using propylene oxide. The first stage of the developed scheme (preparation of pyridylalkanones) occurs in rather low yields, about 35 %. But, after the rearrangement, hydrolysis and the formation of zwitterion do not cause difficulties and are characterized by high yields. Consequently, the proposed synthetic sequence is preparatively advantageous.
{"title":"SYNTHETIC PYRIDINE SUBSTITUTED AMINO ACIDS AND THEIR DERIVATIVES","authors":"S. Shilin, Z. Voitenko, M. Nechai","doi":"10.17721/1728-2209.2019.1(56).5","DOIUrl":"https://doi.org/10.17721/1728-2209.2019.1(56).5","url":null,"abstract":"This paper reports on the synthesis of new derivatives of ε-aminocaproic and γ-aminobutyric acid modified with a pyridin-2-yl substituent at the ω-position of the main chain. The hemostatic activity of both ε-aminocaproic acid itself and its various synthetic analogues is widely known. Likewise, numerous γ-aminobutyric acid derivatives are strong neurotransmitters extensively used in the treatment of the nervous system disorders. No less popular are biologically active substances containing a pyridine or piperidine fragment; among which there are antibiotics, antimalarial, anti-sclerotic and antiallergic drugs, as well as anti-depressants and analgesics. Therefore, the introduction of the pyridine fragment into the amino acid structures is interesting in terms of their potential biological activity investigation. So, a method for the synthesis of 5-amino-5-(pyridin-2-yl)pentanoic and 6-amino-6-(pyridin-2-yl)hexanoic acid has been developed by us. The proposed scheme is based on the available reagents using. The key stage is the Schmidt rearrangement of 2-(pyridin-2-yl)cyclopentanone and 2-(pyridin-2-yl)cyclohexanone, previously synthesized from pyridine N-oxide and cycloalkenyl morpholinide. For synthesized pyridine substituted cycloalkanones according to NMR spectroscopy, the presence of keto-enol tautomerism was established. As a result of Schmidt rearrangement, lactams (2-(pyridin-2-yl)piperidone and 2-(pyridin-2-yl)azepanone) are formed, and the last ones had been hydrolyzed in an acidic medium to open the lactam cycle. Thus, 5-amino-5-(pyridin-2-yl)pentanoic and 6-amino-6-(pyridin-2-yl)hexanoic acid were isolated as hydrochlorides and the hydrochlorides were converted to the zwitterion form using propylene oxide. The first stage of the developed scheme (preparation of pyridylalkanones) occurs in rather low yields, about 35 %. But, after the rearrangement, hydrolysis and the formation of zwitterion do not cause difficulties and are characterized by high yields. Consequently, the proposed synthetic sequence is preparatively advantageous.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"11 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72617337","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 : 2019-01-01DOI: 10.17721/1728-2209.2019.1(56).11
O. Nikolaeva, L. Vretik, E. Yanovska, O. Kondratenko, G. Tun
The determination of the copolymers of 4-vinylpyridine with styrene copolymers real composition, formed under the conditions of precipitation copolymerization in CCl4, is described. For this, 4-vinylpyridine with styrene was copolymerized in different ratios. The composition of the obtained copolymers was determined according to 1H NMR spectroscopy. A comparison of the real copolymers composition with the theoretically calculated ones was performed as well. The copolymerization of styrene with 4-vinylpyridine was carried out in sealed ampoules in argon medium. Solutions of a concentration of 1.02 mol/l in CCl4 were prepared. The initiator azobisisobutyronitrile in the amount of 0.00106 mol/l was added. The copolymerization was carried out in a thermostat C1823 at T = 75 ± 0.5°C. The copolymerization time was 3 hours. The original ratio of monomers (4-vinylpyridine:styrene) = 6:1; 5:1; 4:1; 3:1; 2:1; 1:2; 1:3; 1:4; 1:5; 1:6. The composition of the obtained copolymers was determined according to 1H NMR spectroscopy. It was determined that copolymers of 4-vinylpyridine with styrene obtained by precipitation copolymerization in CCl4 were enriched by 4-vinylpyridine bonds. On the contrary, the calculation of the instant composition of the copolymers according to the literature shows that under the conditions of classical copolymerization in 4-vinylpyridine solution is less active than styrene. We calculated the theoretical relative constants of copolymerization of styrene with 4-vinylpyridine: r1 = 1.97; r2 = 0.93. Therefore, under the conditions of classical copolymerization in solution 4-vinylpyridine is less active than styrene (r2 < r1). It was also found out that for the original molar content of styrene if it is greater than 0,85, it is not possible to synthesize by means of precipitation polymerization into CCl4 the copolymers of 4-vinylpyridine:styrene.
{"title":"PRECIPITATION COPOLYMERIZATION OF 4-VINYLPYRIDINE AND STYRENE","authors":"O. Nikolaeva, L. Vretik, E. Yanovska, O. Kondratenko, G. Tun","doi":"10.17721/1728-2209.2019.1(56).11","DOIUrl":"https://doi.org/10.17721/1728-2209.2019.1(56).11","url":null,"abstract":"The determination of the copolymers of 4-vinylpyridine with styrene copolymers real composition, formed under the conditions of precipitation copolymerization in CCl4, is described. For this, 4-vinylpyridine with styrene was copolymerized in different ratios. The composition of the obtained copolymers was determined according to 1H NMR spectroscopy. A comparison of the real copolymers composition with the theoretically calculated ones was performed as well. The copolymerization of styrene with 4-vinylpyridine was carried out in sealed ampoules in argon medium. Solutions of a concentration of 1.02 mol/l in CCl4 were prepared. The initiator azobisisobutyronitrile in the amount of 0.00106 mol/l was added. The copolymerization was carried out in a thermostat C1823 at T = 75 ± 0.5°C. The copolymerization time was 3 hours. The original ratio of monomers (4-vinylpyridine:styrene) = 6:1; 5:1; 4:1; 3:1; 2:1; 1:2; 1:3; 1:4; 1:5; 1:6. The composition of the obtained copolymers was determined according to 1H NMR spectroscopy. It was determined that copolymers of 4-vinylpyridine with styrene obtained by precipitation copolymerization in CCl4 were enriched by 4-vinylpyridine bonds. On the contrary, the calculation of the instant composition of the copolymers according to the literature shows that under the conditions of classical copolymerization in 4-vinylpyridine solution is less active than styrene. We calculated the theoretical relative constants of copolymerization of styrene with 4-vinylpyridine: r1 = 1.97; r2 = 0.93. Therefore, under the conditions of classical copolymerization in solution 4-vinylpyridine is less active than styrene (r2 < r1). It was also found out that for the original molar content of styrene if it is greater than 0,85, it is not possible to synthesize by means of precipitation polymerization into CCl4 the copolymers of 4-vinylpyridine:styrene.","PeriodicalId":9359,"journal":{"name":"Bulletin of Taras Shevchenko National University of Kyiv. Chemistry","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89237394","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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