B. Brasil, Ingrid C. Chipoline, Vanessa Nascimento
: Chagas disease, considered by the World Health Organization as a neglected tropical disease, is responsible for the deaths of more than 10,000 people annually. The main drugs used to overcome the disease, Benzonidazole and Nifurtimox, besides being old, have limitations regarding the adverse effects related to the treatment time and, consequently, their toxicity. Therefore, the need for a new drug to be used against this disease becomes evident. The classes of organoselenium and aromatic heterocycles 1,2,3-triazoles are promising for the issue of the profile of both classes for further evaluation against Trypanossoma cruzi, since the known chemistry and antiparasitic activity of both have already been described. In this work, the molecular hybridization technique was used in order to combine the individual bioactive protozoan that causes Chagas disease. The methodology used was based on works described in the literature. Initially, benzene azides were synthesized from commercial anilines, while ethynyl(phenyl)selane came from different aromatic diselenides. With these intermediates, a 1,3-dipolar cycle-addition was performed to obtain the new target molecules 1-phenyl-4-(phenylselanyl)-1H-1,2,3-triazoles, with moderate to good yields ranging from 52 to 75%. The characterization of the final molecules is in process and, when finished, they will be sent for evaluation of biological activity. It is possible to conclude that the method used is simple and easy to access, an important factor for potential drugs against neglected diseases. After the assessment of bioactivity, it will be possible to identify the efficiency of these substances, as well as, if necessary, the optimization of their structure.
{"title":"Synthesis of New Selenides-1,2,3-triazoles With Potential Activity Against Trypanossoma cruzi","authors":"B. Brasil, Ingrid C. Chipoline, Vanessa Nascimento","doi":"10.3390/eccs2020-07757","DOIUrl":"https://doi.org/10.3390/eccs2020-07757","url":null,"abstract":": Chagas disease, considered by the World Health Organization as a neglected tropical disease, is responsible for the deaths of more than 10,000 people annually. The main drugs used to overcome the disease, Benzonidazole and Nifurtimox, besides being old, have limitations regarding the adverse effects related to the treatment time and, consequently, their toxicity. Therefore, the need for a new drug to be used against this disease becomes evident. The classes of organoselenium and aromatic heterocycles 1,2,3-triazoles are promising for the issue of the profile of both classes for further evaluation against Trypanossoma cruzi, since the known chemistry and antiparasitic activity of both have already been described. In this work, the molecular hybridization technique was used in order to combine the individual bioactive protozoan that causes Chagas disease. The methodology used was based on works described in the literature. Initially, benzene azides were synthesized from commercial anilines, while ethynyl(phenyl)selane came from different aromatic diselenides. With these intermediates, a 1,3-dipolar cycle-addition was performed to obtain the new target molecules 1-phenyl-4-(phenylselanyl)-1H-1,2,3-triazoles, with moderate to good yields ranging from 52 to 75%. The characterization of the final molecules is in process and, when finished, they will be sent for evaluation of biological activity. It is possible to conclude that the method used is simple and easy to access, an important factor for potential drugs against neglected diseases. After the assessment of bioactivity, it will be possible to identify the efficiency of these substances, as well as, if necessary, the optimization of their structure.","PeriodicalId":151361,"journal":{"name":"Proceedings of 1st International Electronic Conference on Catalysis Sciences","volume":"228 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116559147","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}
V. Koroleva, S. Olshannikova, M. Holyavka, A. Pashkov, V. Artyukhov
: Immobilized enzymes are the most sought-after preparations in the global market. They are used in medicine, veterinary medicine, the food industry, winemaking and brewing. The simplest method for immobilizing biocatalysts on insoluble carriers is the simple adsorption method. Its advantage is that it preserves the natural conformation of the enzyme, which slightly reduces its catalytic ability compared to the native form. In our study, we carried out the selection of optimal conditions for adsorption immobilization of acid-soluble chitosan (Mr = 350 kDa) enzymes of plant origin (ficin, papain and bromelain) on a matrix. Ficin (EC 3.4.22.3), papain (EC 3.4.22.2) and bromelain (EC 3.4.22.4) (Sigma) were chosen as the objects of study, azocasein (Sigma) was used as a substrate for hydrolysis and an acid-soluble high-molecular-weight chitosan (350 kDa) was used as an immobilization matrix, synthesized by Bioprogress CJSC. Suitable buffer systems for immobilization were identified by the optimal ratio of protein content and total and specific activity. Ficin is immobilized on a chitosan matrix using glycine buffer with a pH of 8.6. Glycine buffer with a pH of 8.6–10.5 is an optimal medium for sorption of papain on chitosan. Bromelain is immobilized on a chitosan matrix under Tris-glycine buffer with pH 8.5 conditions.
{"title":"Selection of the Optimal Medium for Adsorption of Plant Protease","authors":"V. Koroleva, S. Olshannikova, M. Holyavka, A. Pashkov, V. Artyukhov","doi":"10.3390/eccs2020-07525","DOIUrl":"https://doi.org/10.3390/eccs2020-07525","url":null,"abstract":": Immobilized enzymes are the most sought-after preparations in the global market. They are used in medicine, veterinary medicine, the food industry, winemaking and brewing. The simplest method for immobilizing biocatalysts on insoluble carriers is the simple adsorption method. Its advantage is that it preserves the natural conformation of the enzyme, which slightly reduces its catalytic ability compared to the native form. In our study, we carried out the selection of optimal conditions for adsorption immobilization of acid-soluble chitosan (Mr = 350 kDa) enzymes of plant origin (ficin, papain and bromelain) on a matrix. Ficin (EC 3.4.22.3), papain (EC 3.4.22.2) and bromelain (EC 3.4.22.4) (Sigma) were chosen as the objects of study, azocasein (Sigma) was used as a substrate for hydrolysis and an acid-soluble high-molecular-weight chitosan (350 kDa) was used as an immobilization matrix, synthesized by Bioprogress CJSC. Suitable buffer systems for immobilization were identified by the optimal ratio of protein content and total and specific activity. Ficin is immobilized on a chitosan matrix using glycine buffer with a pH of 8.6. Glycine buffer with a pH of 8.6–10.5 is an optimal medium for sorption of papain on chitosan. Bromelain is immobilized on a chitosan matrix under Tris-glycine buffer with pH 8.5 conditions.","PeriodicalId":151361,"journal":{"name":"Proceedings of 1st International Electronic Conference on Catalysis Sciences","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124820130","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 green and sustainable approach for the production of 3-aminobenzoic acid (3-ABA) from 3-nitrobenzaldehyde promoted by NORIT GAC 12-40 as a carbonaceous bio-based material was successfully achieved in subcritical water. The process involves two successive reactions: reduction of the nitro group and oxidation of the formyl group. At 300 °C under 90 bar for 6 h, the yield of 3-ABA is 59%.
{"title":"One-Pot Green Catalytic Preparation of 3-Aminobenzoic Acid in the Presence of Carbonaceous Bio-Based Materials in Subcritical Water","authors":"Sarra Tadrent, C. Len","doi":"10.3390/eccs2020-07541","DOIUrl":"https://doi.org/10.3390/eccs2020-07541","url":null,"abstract":": A green and sustainable approach for the production of 3-aminobenzoic acid (3-ABA) from 3-nitrobenzaldehyde promoted by NORIT GAC 12-40 as a carbonaceous bio-based material was successfully achieved in subcritical water. The process involves two successive reactions: reduction of the nitro group and oxidation of the formyl group. At 300 °C under 90 bar for 6 h, the yield of 3-ABA is 59%.","PeriodicalId":151361,"journal":{"name":"Proceedings of 1st International Electronic Conference on Catalysis Sciences","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132121466","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. Tabanelli, Paola Blair Vásquez, E. Paone, R. Pietropaolo, N. Dimitratos, F. Cavani, F. Mauriello
: Levulinic acid (LA) and its esters (alkyl levulinates) are polyfunctional molecules that can be obtained from lignocellulosic biomass. Herein, the catalytic conversion of methyl and ethyl levulinates into γ -valerolactone (GVL) via catalytic transfer hydrogenation (CTH) by using methanol, ethanol, and 2-propanol as the H-donor/solvent, was investigated under both batch and gas-flow conditions. In particular, high-surface-area, tetragonal zirconia has proven to be a suitable catalyst for this reaction. Isopropanol was found to be the best H-donor under batch conditions, with ethyl levulinate providing the highest yield in GVL. However, long reaction times and high autogenic pressures are needed in order to work in the liquid-phase at high temperature with light alcohols. The reactions occurring under continuous gas-flow conditions, at atmospheric pressure and a relatively low contact time (1 s), were found to be much more efficient, also showing excellent GVL yields when EtOH was used as the reducing agent (GVL yield of around 70% under optimized conditions). The reaction has also been tested using a true bio-ethanol, derived from agricultural waste. These results represent the very first examples of the CTH of alkyl levulinates under continuous gas-flow conditions reported in the literature.
{"title":"Improved Catalytic Transfer Hydrogenation of Levulinate Esters with Alcohols over ZrO2 Catalyst","authors":"T. Tabanelli, Paola Blair Vásquez, E. Paone, R. Pietropaolo, N. Dimitratos, F. Cavani, F. Mauriello","doi":"10.3390/eccs2020-07585","DOIUrl":"https://doi.org/10.3390/eccs2020-07585","url":null,"abstract":": Levulinic acid (LA) and its esters (alkyl levulinates) are polyfunctional molecules that can be obtained from lignocellulosic biomass. Herein, the catalytic conversion of methyl and ethyl levulinates into γ -valerolactone (GVL) via catalytic transfer hydrogenation (CTH) by using methanol, ethanol, and 2-propanol as the H-donor/solvent, was investigated under both batch and gas-flow conditions. In particular, high-surface-area, tetragonal zirconia has proven to be a suitable catalyst for this reaction. Isopropanol was found to be the best H-donor under batch conditions, with ethyl levulinate providing the highest yield in GVL. However, long reaction times and high autogenic pressures are needed in order to work in the liquid-phase at high temperature with light alcohols. The reactions occurring under continuous gas-flow conditions, at atmospheric pressure and a relatively low contact time (1 s), were found to be much more efficient, also showing excellent GVL yields when EtOH was used as the reducing agent (GVL yield of around 70% under optimized conditions). The reaction has also been tested using a true bio-ethanol, derived from agricultural waste. These results represent the very first examples of the CTH of alkyl levulinates under continuous gas-flow conditions reported in the literature.","PeriodicalId":151361,"journal":{"name":"Proceedings of 1st International Electronic Conference on Catalysis Sciences","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129982037","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}
Luana Bettanin, Filipe Penteado, Luiz H. Dapper, E. Lenardão
: We developed a promising synthetic methodology for the regioselective photocatalyzed 3-selenocyanation of indoles, employing potassium selenocyanate (KSeCN) and a blue LED light. The 3-selanylindoles have been emerging as a potentially bioactive class of compounds and already have demonstrated anti-inflammatory, antinociceptive and anticancer properties. There are in the literature several methodologies for their preparation; for example, applying intermolecular cyclization with Se-based electrophilic species. Therefore, it is of interest to seek innovative and effective methodologies to selectively access this class of molecules. Furthermore, the photocatalytically formed NCSe· radical can react directly with the N -heterocycle unsaturated substrates, affording the desired compound more effectively than other electrophilic selenium species. In addition, the 3-selenocyanato-1 H -indole derivatives can be employed as precursor to obtaining diselenides, through a reduction–oxidation reaction sequence. The new method employs indole as unsaturated N -heterocycle substrate, and 1.3 equiv. of potassium selenocyanate as a selenium source, in the presence of 5.0 mol% of eosin Y, an organic photocatalyst, and 1.0 mL of acetonitrile. The system was stirred and irradiated with a blue LED light for 5 h, and the crude was purified using column chromatography. Thus, as a result, we developed an efficient and smoothly methodology to prepare 3-selenocyanato-1 H -indole derivatives, in good yields. KSeCN ( 2 ), 5 mol% of organic photocatalyst, and solvent (1.0 mL). The mixture reaction was stirring for 5 h at the room temperature under visible light irradiation. The consumption of starting materials was monitored by TLC; b isolated yields obtained by chromatographic column.
我们开发了一种很有前途的区域选择性光催化吲哚3-硒氰化合成方法，采用硒氰酸钾(KSeCN)和蓝色LED灯。3-selanylindoles已经成为一种潜在的生物活性化合物，并且已经被证明具有抗炎、抗伤和抗癌的特性。在文献中有几种方法来准备它们;例如，应用分子间环化与基于se的亲电物质。因此，寻求创新和有效的方法来选择性地获取这类分子是人们感兴趣的。此外，光催化形成的NCSe·自由基可以直接与N -杂环不饱和底物反应，比其他亲电性硒更有效地提供所需的化合物。此外，3-硒氰酸酯-1 H -吲哚衍生物可以通过还原-氧化反应序列作为前体得到二硒化物。该方法以吲哚为不饱和N -杂环底物，1.3等量的硒氰酸钾为硒源，在5.0 mol%的伊红Y、有机光催化剂和1.0 mL乙腈的存在下进行。搅拌后用蓝色LED灯照射5h，用柱层析纯化。因此，我们开发了一种高效、平稳的方法来制备3-硒氰酸酯-1 H -吲哚衍生物，收率高。KSeCN (2)， 5 mol%有机光催化剂，溶剂(1.0 mL)。在可见光照射下，室温搅拌反应5h。采用薄层色谱法监测原料消耗;B分离收率通过色谱柱得到。
{"title":"Selenocyanation of Indoles Promoted by Visible-Light","authors":"Luana Bettanin, Filipe Penteado, Luiz H. Dapper, E. Lenardão","doi":"10.3390/eccs2020-07562","DOIUrl":"https://doi.org/10.3390/eccs2020-07562","url":null,"abstract":": We developed a promising synthetic methodology for the regioselective photocatalyzed 3-selenocyanation of indoles, employing potassium selenocyanate (KSeCN) and a blue LED light. The 3-selanylindoles have been emerging as a potentially bioactive class of compounds and already have demonstrated anti-inflammatory, antinociceptive and anticancer properties. There are in the literature several methodologies for their preparation; for example, applying intermolecular cyclization with Se-based electrophilic species. Therefore, it is of interest to seek innovative and effective methodologies to selectively access this class of molecules. Furthermore, the photocatalytically formed NCSe· radical can react directly with the N -heterocycle unsaturated substrates, affording the desired compound more effectively than other electrophilic selenium species. In addition, the 3-selenocyanato-1 H -indole derivatives can be employed as precursor to obtaining diselenides, through a reduction–oxidation reaction sequence. The new method employs indole as unsaturated N -heterocycle substrate, and 1.3 equiv. of potassium selenocyanate as a selenium source, in the presence of 5.0 mol% of eosin Y, an organic photocatalyst, and 1.0 mL of acetonitrile. The system was stirred and irradiated with a blue LED light for 5 h, and the crude was purified using column chromatography. Thus, as a result, we developed an efficient and smoothly methodology to prepare 3-selenocyanato-1 H -indole derivatives, in good yields. KSeCN ( 2 ), 5 mol% of organic photocatalyst, and solvent (1.0 mL). The mixture reaction was stirring for 5 h at the room temperature under visible light irradiation. The consumption of starting materials was monitored by TLC; b isolated yields obtained by chromatographic column.","PeriodicalId":151361,"journal":{"name":"Proceedings of 1st International Electronic Conference on Catalysis Sciences","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133384159","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. Priyadarsini, B. Singh, P. Phadnis, K. C. Barick, P. Hassan
: One of the important features influencing the biological applications of organoselenium compounds is their redox state, which in turn is affected by their interactions with nearby heteroatoms. To modulate the biological action of selenium in such compounds, researchers have designed new structural motifs and also developed new formulations using inorganic nanoparticles. Metal nanoparticles such as gold nanoparticles (GNPs) and magnetic nanoparticles (MNPs) like iron oxide (Fe 3 O 4 ) have been extensively studied for conjugation with many heteroatoms (sulphur, nitrogen and oxygen) containing ligands. Selenium, being more polarisable than sulphur, can induce significant surface passivation, thereby providing easy modulations with physico-chemical properties. Considering this, we investigated the physico-chemical properties of a few selenium compounds conjugated to GNPs and MNPs. The GNP conjugates were characterised by spectroscopic and microscopic tools, such as optical absorption, Raman spectroscopy, dynamic light scattering (DLS), the zeta potential and transmission electron microscopy (TEM). The results confirmed that the selenium atom was covalently conjugated to GNPs and this conjugation not only increased their electron transfer ability, but also their antioxidant ability. In another study, asymmetric phenyl selenides were conjugated with MNPs and characterised byX-ray diffraction (XRD), TEM, DLS and zeta potential. The radical scavenging ability of the selenium compounds improved upon conjugation with the MNPs. Therefore, the above studies confirmed that the redox activities of selenium compounds can be modulated upon conjugation with inorganic nanoparticles, such as GNPs and MNPs, which in turn provides new avenues for delivering organoselenium compounds.
{"title":"Nanoparticle Conjugates of Selenium Compounds: Preparation, Characterisation and Electron Transfer Reactions","authors":"K. Priyadarsini, B. Singh, P. Phadnis, K. C. Barick, P. Hassan","doi":"10.3390/eccs2020-07545","DOIUrl":"https://doi.org/10.3390/eccs2020-07545","url":null,"abstract":": One of the important features influencing the biological applications of organoselenium compounds is their redox state, which in turn is affected by their interactions with nearby heteroatoms. To modulate the biological action of selenium in such compounds, researchers have designed new structural motifs and also developed new formulations using inorganic nanoparticles. Metal nanoparticles such as gold nanoparticles (GNPs) and magnetic nanoparticles (MNPs) like iron oxide (Fe 3 O 4 ) have been extensively studied for conjugation with many heteroatoms (sulphur, nitrogen and oxygen) containing ligands. Selenium, being more polarisable than sulphur, can induce significant surface passivation, thereby providing easy modulations with physico-chemical properties. Considering this, we investigated the physico-chemical properties of a few selenium compounds conjugated to GNPs and MNPs. The GNP conjugates were characterised by spectroscopic and microscopic tools, such as optical absorption, Raman spectroscopy, dynamic light scattering (DLS), the zeta potential and transmission electron microscopy (TEM). The results confirmed that the selenium atom was covalently conjugated to GNPs and this conjugation not only increased their electron transfer ability, but also their antioxidant ability. In another study, asymmetric phenyl selenides were conjugated with MNPs and characterised byX-ray diffraction (XRD), TEM, DLS and zeta potential. The radical scavenging ability of the selenium compounds improved upon conjugation with the MNPs. Therefore, the above studies confirmed that the redox activities of selenium compounds can be modulated upon conjugation with inorganic nanoparticles, such as GNPs and MNPs, which in turn provides new avenues for delivering organoselenium compounds.","PeriodicalId":151361,"journal":{"name":"Proceedings of 1st International Electronic Conference on Catalysis Sciences","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115197314","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. Rinaudo, A. M. Beltrán, M. Fernández, L. Cadús, M. R. Morales
: Palladium nanoparticles were supported on unusual mixtures of anatase, TiO 2 (II) and rutile titania phases by wet impregnation, obtaining catalysts with metal contents of ca. 0.25 wt % labeled Pd/Ti5, Pd/Ti45, and Pd/Ti120. Crystalline structures were confirmed by X-ray diffraction. Pd particle sizes in the range of 4–20 nm were observed by scanning-transmission electron Microscopy. External surface areas (S BET ) in the range 10–17 m 2 g − 1 were higher enough to achieve a good distribution of palladium over titanium oxide outer surface, as evidenced by energy-dispersive X-ray spectroscopy elemental profiles. Pd 0 /Pd δ + atomic ratio measured by X-ray photoelectron spectroscopy showed a decrease from Pd/Ti5 to Pd/Ti120, in line with the decrease in anatase phase present in the catalysts. This behavior suggested that palladium tended to form more TiPd x O structures in Pd/Ti5 whilst PdO x structures were more likely to be present on supports with greater amounts of TiO 2 (II) and rutile, due to the distinct metal–support interactions. An increase in reducibility and oxygen mobility from Pd/Ti5 to Pd/Ti120 was observed by temperature programmed measurements and associated to the different high-energy ball milled supports. Catalysts with improved properties reported herein could exhibit an excellent performance in oxidation reactions, e.g., glycerol selective oxidation. inducing low-temperature reducibility and an increase in the mobility of reactive oxygen species, as evidenced by TPM analyses, factors well-known to benefit oxidation reactions. Present catalysts are being tested in liquid-phase glycerol selective oxidation in order to study the influence of metal– support interactions on the catalytic performance.
{"title":"Synthesis and Characterization of Pd over Novel TiO2 Mixtures: Insights on Metal-Support Interactions","authors":"M. Rinaudo, A. M. Beltrán, M. Fernández, L. Cadús, M. R. Morales","doi":"10.3390/eccs2020-07529","DOIUrl":"https://doi.org/10.3390/eccs2020-07529","url":null,"abstract":": Palladium nanoparticles were supported on unusual mixtures of anatase, TiO 2 (II) and rutile titania phases by wet impregnation, obtaining catalysts with metal contents of ca. 0.25 wt % labeled Pd/Ti5, Pd/Ti45, and Pd/Ti120. Crystalline structures were confirmed by X-ray diffraction. Pd particle sizes in the range of 4–20 nm were observed by scanning-transmission electron Microscopy. External surface areas (S BET ) in the range 10–17 m 2 g − 1 were higher enough to achieve a good distribution of palladium over titanium oxide outer surface, as evidenced by energy-dispersive X-ray spectroscopy elemental profiles. Pd 0 /Pd δ + atomic ratio measured by X-ray photoelectron spectroscopy showed a decrease from Pd/Ti5 to Pd/Ti120, in line with the decrease in anatase phase present in the catalysts. This behavior suggested that palladium tended to form more TiPd x O structures in Pd/Ti5 whilst PdO x structures were more likely to be present on supports with greater amounts of TiO 2 (II) and rutile, due to the distinct metal–support interactions. An increase in reducibility and oxygen mobility from Pd/Ti5 to Pd/Ti120 was observed by temperature programmed measurements and associated to the different high-energy ball milled supports. Catalysts with improved properties reported herein could exhibit an excellent performance in oxidation reactions, e.g., glycerol selective oxidation. inducing low-temperature reducibility and an increase in the mobility of reactive oxygen species, as evidenced by TPM analyses, factors well-known to benefit oxidation reactions. Present catalysts are being tested in liquid-phase glycerol selective oxidation in order to study the influence of metal– support interactions on the catalytic performance.","PeriodicalId":151361,"journal":{"name":"Proceedings of 1st International Electronic Conference on Catalysis Sciences","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122608782","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}
: UV irradiation is an essential factor in natural and artificial climate in modern environmental conditions, which has a constant effect on living systems. Collagenase, bromelain, ficin, papain (Sigma-Aldrich: St. Louis, MO, USA) and trypsin (MP biomedicals: Santa Ana, CA, USA) were the objects of this study. The substrate for hydrolysis was BSA (Sigma-Aldrich: St. Louis, MO, USA), the carriers for immobilization were chitosans (<100, 200 and 350 kDa) and chitosan succinate (Bioprogress: Shchyolkovo, Russia). The protease immobilization was carried out by the adsorption. The determination of the protein amount in samples and their catalytic activity was carried out by the modified Lowry method. UV irradiation of proteases was performed using doses 151–6040 J/m 2 . By the degree of photosensitivity, hydrolases can be arranged in the next row: collagenase → bromelain → ficin → papain → trypsin. Adsorption on a chitosan and succinate of chitosan leads to an increase in the stability to ultraviolet light of heterogeneous (immobilized) biocatalysts compared to free enzymes. Photoprotective effect of the chitosan may be due to the following reasons: enzyme interact with the chitosan to form photo resistant complexes; с hitosan screens active free-radicals, preventing the photooxidation of a certain number of amino acids, including the active centers of the studied enzymes under the influence of UV irradiation.
:在现代环境条件下，紫外线辐射是自然和人工气候的重要因素，对生命系统具有持续的影响。胶原酶、菠萝蛋白酶、无花果蛋白酶、木瓜蛋白酶(Sigma-Aldrich: St. Louis, MO, USA)和胰蛋白酶(MP biomedicals: Santa Ana, CA, USA)是本研究的对象。水解底物为BSA (Sigma-Aldrich: St. Louis, MO, USA)，固定化载体为壳聚糖(< 100,200和350 kDa)和壳聚糖丁二酸盐(Bioprogress: Shchyolkovo, Russia)。采用吸附法固定化蛋白酶。采用改进的Lowry法测定样品中的蛋白质量及其催化活性。对蛋白酶进行剂量为151 ~ 6040 J/ m2的紫外线照射。水解酶按光敏程度依次排列为:胶原酶→菠萝蛋白酶→无花果蛋白酶→木瓜蛋白酶→胰蛋白酶。与游离酶相比，壳聚糖和壳聚糖琥珀酸盐对多相(固定化)生物催化剂的紫外稳定性有所提高。壳聚糖的光保护作用可能是由于以下原因:酶与壳聚糖相互作用形成抗光复合物;木聚糖屏蔽活性自由基，防止某些氨基酸的光氧化，包括在所研究的酶的活性中心在紫外线照射的影响下。
{"title":"UV-Sensitivity of Free and Immobilized on Chitosan Matrix Proteases","authors":"S. Pankova, M. Holyavka, V. Artyukhov","doi":"10.3390/eccs2020-07610","DOIUrl":"https://doi.org/10.3390/eccs2020-07610","url":null,"abstract":": UV irradiation is an essential factor in natural and artificial climate in modern environmental conditions, which has a constant effect on living systems. Collagenase, bromelain, ficin, papain (Sigma-Aldrich: St. Louis, MO, USA) and trypsin (MP biomedicals: Santa Ana, CA, USA) were the objects of this study. The substrate for hydrolysis was BSA (Sigma-Aldrich: St. Louis, MO, USA), the carriers for immobilization were chitosans (<100, 200 and 350 kDa) and chitosan succinate (Bioprogress: Shchyolkovo, Russia). The protease immobilization was carried out by the adsorption. The determination of the protein amount in samples and their catalytic activity was carried out by the modified Lowry method. UV irradiation of proteases was performed using doses 151–6040 J/m 2 . By the degree of photosensitivity, hydrolases can be arranged in the next row: collagenase → bromelain → ficin → papain → trypsin. Adsorption on a chitosan and succinate of chitosan leads to an increase in the stability to ultraviolet light of heterogeneous (immobilized) biocatalysts compared to free enzymes. Photoprotective effect of the chitosan may be due to the following reasons: enzyme interact with the chitosan to form photo resistant complexes; с hitosan screens active free-radicals, preventing the photooxidation of a certain number of amino acids, including the active centers of the studied enzymes under the influence of UV irradiation.","PeriodicalId":151361,"journal":{"name":"Proceedings of 1st International Electronic Conference on Catalysis Sciences","volume":"30 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122797305","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}
Erick Fabian Mosquera Quiñonez, J. E. Morales, M. Mina
: Ecuador is one of the countries in the Latin American region with a high textile production. However, chemical treatment strategies in the Ambato, Tungurahua and Quito areas are inefficient and not systematically applied, and the volumes of dyes and pigment-type contaminants generate serious environmental problems. The treatments of indigo textile wastewater and related indigo derivatives are very complex. Taking these into consideration, a simple photochemical protocol in heterogeneous conditions was developed, for degrading “blue-indigo” (Ambato textile group) in solution, using TiO 2 (Degussa P25, with a purity of ≈ 99% and BET surface area 50 ± 15 m 2 /g) and solar light at lab scale. The photocatalytic oxidation of “blue-indigo” in aqueous solution was assessed by solar irradiation, in the presence of TiO 2 particles. The effect of indigo concentrations, pH and TiO 2 loading for maximum degree of degradation were evaluated. The mineralization of “blue-indigo” was reported by measuring COD-i and COD-f of the solution that was irradiated with sunlight under optimized conditions. The results enable the re-designing of strategies for controlling contamination in textile wastewaters in eco-sustainable conditions for Ecuador.
{"title":"Photochemical Treatment of Blue-Indigo using TiO2-Sunligth System in Heterogeneous Conditions.†","authors":"Erick Fabian Mosquera Quiñonez, J. E. Morales, M. Mina","doi":"10.3390/eccs2020-07526","DOIUrl":"https://doi.org/10.3390/eccs2020-07526","url":null,"abstract":": Ecuador is one of the countries in the Latin American region with a high textile production. However, chemical treatment strategies in the Ambato, Tungurahua and Quito areas are inefficient and not systematically applied, and the volumes of dyes and pigment-type contaminants generate serious environmental problems. The treatments of indigo textile wastewater and related indigo derivatives are very complex. Taking these into consideration, a simple photochemical protocol in heterogeneous conditions was developed, for degrading “blue-indigo” (Ambato textile group) in solution, using TiO 2 (Degussa P25, with a purity of ≈ 99% and BET surface area 50 ± 15 m 2 /g) and solar light at lab scale. The photocatalytic oxidation of “blue-indigo” in aqueous solution was assessed by solar irradiation, in the presence of TiO 2 particles. The effect of indigo concentrations, pH and TiO 2 loading for maximum degree of degradation were evaluated. The mineralization of “blue-indigo” was reported by measuring COD-i and COD-f of the solution that was irradiated with sunlight under optimized conditions. The results enable the re-designing of strategies for controlling contamination in textile wastewaters in eco-sustainable conditions for Ecuador.","PeriodicalId":151361,"journal":{"name":"Proceedings of 1st International Electronic Conference on Catalysis Sciences","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122906544","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}
: Methylmercury (MeHg + ) is an important environmental contaminant and its toxicity is associated with its interaction with selenium (e.g., selenol groups of selenoproteins or HSe − , which is the pivotal metabolite for Se incorporation into selenoproteins). We hypothesized that (PhSe) 2 mediated MeHg + detoxification could be indirectly altered by its open or closed conformation. The two conformations of (PhSe) 2 were located on the potential energy surface (PES) computed at ZORA-OPBE-D3(BJ)/ZORA-def2-TZVP level of theory. HPLC analysis indicated that (PhSe) 2 did not react with MeHg + , but its reduced intermediate formed a stable complex with MeHg + . The nudged elastic band (NEB) method revealed conformational changes from closed to open state with an H − (2 electrons) transfer from NaBH 4 , forming a reactant complex-like transition state (TS). The UV-Vis spectrophotometer used in combination with the time-dependent density functional theory (TD-DFT) indicated that the signal of (PhSe) 2 at 239 nm was possibly the open conformer’s signal with oscillator strength 0.1 and a π → π * electron transfer character. The experimental band gap energy of (PhSe) 2 at 5.20 eV matched to the excitation energy of the open conformation. The local softness (S − ) on the selenium atoms almost doubles, as state changes from closed to open. The theoretical results have indicated that the open conformation of (PhSe) 2 is likely the one that reacts with NaBH 4 to form the PhSeH, which can react with MeHg + .
{"title":"Integrating Diphenyl Diselenide and Its MeHg+ Detoxificant Mechanism on a Conceptual DFT Framework","authors":"F. B. Omage, C. Oliveira, L. Orian, J. Rocha","doi":"10.3390/eccs2020-07577","DOIUrl":"https://doi.org/10.3390/eccs2020-07577","url":null,"abstract":": Methylmercury (MeHg + ) is an important environmental contaminant and its toxicity is associated with its interaction with selenium (e.g., selenol groups of selenoproteins or HSe − , which is the pivotal metabolite for Se incorporation into selenoproteins). We hypothesized that (PhSe) 2 mediated MeHg + detoxification could be indirectly altered by its open or closed conformation. The two conformations of (PhSe) 2 were located on the potential energy surface (PES) computed at ZORA-OPBE-D3(BJ)/ZORA-def2-TZVP level of theory. HPLC analysis indicated that (PhSe) 2 did not react with MeHg + , but its reduced intermediate formed a stable complex with MeHg + . The nudged elastic band (NEB) method revealed conformational changes from closed to open state with an H − (2 electrons) transfer from NaBH 4 , forming a reactant complex-like transition state (TS). The UV-Vis spectrophotometer used in combination with the time-dependent density functional theory (TD-DFT) indicated that the signal of (PhSe) 2 at 239 nm was possibly the open conformer’s signal with oscillator strength 0.1 and a π → π * electron transfer character. The experimental band gap energy of (PhSe) 2 at 5.20 eV matched to the excitation energy of the open conformation. The local softness (S − ) on the selenium atoms almost doubles, as state changes from closed to open. The theoretical results have indicated that the open conformation of (PhSe) 2 is likely the one that reacts with NaBH 4 to form the PhSeH, which can react with MeHg + .","PeriodicalId":151361,"journal":{"name":"Proceedings of 1st International Electronic Conference on Catalysis Sciences","volume":"172 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115991374","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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