Quimica Nova最新文献_第2页

APPLICATIONS OF NMR AND THEORETICAL CALCULATIONS TO STUDY THE O-H∙∙∙N INTRAMOLECULAR HYDROGEN BOND EFFECT ON THE CONFORMATIONAL EQUILIBRIUM OF CIS-3-N-ETHYLAMINOCYCLOHEXANOL AND CIS-3-N,N-DIETHYLAMINOCYCLOHEXANOL 应用核磁共振和理论计算研究o-h∙∙n分子内氢键对顺-3- n -乙基氨基环己醇和顺-3- n, n -二乙基氨基环己醇构象平衡的影响

IF 0.8 4区化学

Quimica Nova Pub Date : 2023-10-09 DOI: 10.21577/0100-4042.20230051

Paulo R. de Oliveira, R. Rittner, Palimécio Guerrero Jr., P. Batista, G. Costa

{"title":"APPLICATIONS OF NMR AND THEORETICAL CALCULATIONS TO STUDY THE O-H∙∙∙N INTRAMOLECULAR HYDROGEN BOND EFFECT ON THE CONFORMATIONAL EQUILIBRIUM OF CIS-3-N-ETHYLAMINOCYCLOHEXANOL AND CIS-3-N,N-DIETHYLAMINOCYCLOHEXANOL","authors":"Paulo R. de Oliveira, R. Rittner, Palimécio Guerrero Jr., P. Batista, G. Costa","doi":"10.21577/0100-4042.20230051","DOIUrl":"https://doi.org/10.21577/0100-4042.20230051","url":null,"abstract":"Textbooks show that in cis-1,3-disubstituted cyclohexane molecule, the conformer with the substituents in the diaxial positions is higher in energy and hence, it presents a low population in the conformational equilibrium. The diaxial conformer is destabilized by the repulsion between the substituent groups and the axial hydrogen atoms on the same side of the ring. This interaction is known as the 1,3-diaxial interaction. In this study, the solvent effect on the conformational equilibria of cis-3-N-ethylaminocyclohexanol (cis-3-EACOL) and cis-3-N,N-diethylaminocyclohexanol (cis-3-DEACOL) has been assessed through the spin-spin coupling constant (3JHH). The results show that the diaxial conformation of cis-3-EACOL decreases from 92% in CCl4 (∆Gee-aa = 1.48 kcal mol-1 ) to 10% in DMSO-d6 (∆Gee-aa = −1.31 kcal mol-1). For cis-3-DEACOL the diaxial conformer decreased from 36% in CCl4 (∆Gee-aa = −0.33 kcal mol-1) to 7% in Pyridine-d5 (∆Gee-aa = −1.55 kcal mol-1). The stabilization of the diaxial conformer in nonpolar solvents takes place due to the O-H···N intramolecular hydrogen bond, which overcomes the 1,3-diaxial steric interactions.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68272059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

DETERMINATION OF RESIDUAL METHANOL AND ETHANOL IN BIODIESEL BY 1H-NMR 氢核磁共振法测定生物柴油中甲醇和乙醇残留量

IF 0.8 4区化学

Quimica Nova Pub Date : 2023-10-09 DOI: 10.21577/0100-4042.20230046

Samuel Santos, Cassiane Dutra, Luiz Fontoura

引用次数: 0

PREDICTION OF ANTI-DIABETIC ALOGLIPTIN STABILITY BY ISOTHERMAL STUDIES 用等温研究预测抗糖尿病阿格列汀的稳定性

IF 0.8 4区化学

Quimica Nova Pub Date : 2023-10-09 DOI: 10.21577/0100-4042.20230050

C. Bertol, Gabriel Felimberti, Karini da Rosa, E. Rizzon, R. Pereira, L. Kreutz, Pedro Froelich

{"title":"PREDICTION OF ANTI-DIABETIC ALOGLIPTIN STABILITY BY ISOTHERMAL STUDIES","authors":"C. Bertol, Gabriel Felimberti, Karini da Rosa, E. Rizzon, R. Pereira, L. Kreutz, Pedro Froelich","doi":"10.21577/0100-4042.20230050","DOIUrl":"https://doi.org/10.21577/0100-4042.20230050","url":null,"abstract":"Alogliptin (ALG) benzoate is an oral hypoglycemic drug that works as a DPP-4 inhibitor to prevent incretin degradation. Forced stability studies use high temperatures to decompose drugs and estimate their behavior at low temperatures. We aimed to evaluate the thermal stability of ALG using two techniques: isothermal thermogravimetry (TGA) and degradation in an oven followed by liquid chromatography (LC-PDA) analysis. ALG was subjected to 150, 155, 160, 165, and 170 °C up to 10% of mass loss in isothermal TGA. In the oven, the drug was submitted to 130, 140, 150, 155, 160, and 170 °C. Kinetic parameters were calculated with the Arrhenius model. ALG followed zero-order kinetics, in which the degradation rate did not depend on reagent concentration. Activation energy ranged from 31.0 to 35.9 kcal mol-1. The degraded drug was less toxic in a cytotoxicity assay in CRIB cells than the undegraded drug. The TGA method is faster and more practical than the oven followed by LC-PDA, and the data present a correlation. Here we described the kinetic parameters of ALG degradation, improving the knowledge about the drug and assisting in developing new formulations from the drug.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

DIFFUSION STUDY OF NaCl AND KCl AT THE SOLUTION/OLIVE INTERFACE: MATHEMATICAL MODELING USING THE FINITE ELEMENT METHOD AND SELF-ORGANIZING FEATURE MAP (SOFM)-TYPE NEURAL NETWORKS NaCl和KCl在溶液/橄榄界面的扩散研究:使用有限元方法和自组织特征映射(SOFM)型神经网络的数学建模

IF 0.8 4区化学

Quimica Nova Pub Date : 2023-10-09 DOI: 10.21577/0100-4042.20230053

D. Borsato, M. Clemente, Heloisa Silva, Nathan Silva, Júlia Campos, Eduardo Sousa, H. Silva, Karina B. Angilelli, A. Mantovani, Rafael Mantovani

引用次数: 0

FUNCTIONAL AND TECHNOLOGICAL PROPERTIES OF COFFEE MUCILAGE (Coffea arabica) AND ITS APPLICATION IN EDIBLE FILMS 咖啡胶浆(阿拉比卡咖啡)的功能、工艺特性及其在食用薄膜中的应用

IF 0.8 4区化学

Quimica Nova Pub Date : 2023-10-09 DOI: 10.21577/0100-4042.20230052

Daiane Machado, R. D. de Oliveira

{"title":"FUNCTIONAL AND TECHNOLOGICAL PROPERTIES OF COFFEE MUCILAGE (Coffea arabica) AND ITS APPLICATION IN EDIBLE FILMS","authors":"Daiane Machado, R. D. de Oliveira","doi":"10.21577/0100-4042.20230052","DOIUrl":"https://doi.org/10.21577/0100-4042.20230052","url":null,"abstract":"Brazil is the largest coffee producer in the world, and together with the millions of tons produced, millions of tons of residues are also generated. The generated residues are a source of environmental contamination depending on the chosen processing route. One of the main applications of food industry waste is in the production of raw materials to produce edible films and coatings. Coffee mucilage is a pectin-rich liquid residue from the coffee sector that can be used in the production of value-added products. Given this, the objective of this work was to characterize and evaluate the potential of functional and technological properties of coffee mucilage and your applicability in the production of edible films. The filmogenic mixture was obtained by casting from 10% (w/v) lyophilized coffee mucilage and solvent (water). The films produced from the coffee mucilage presented good homogeneity, continuity (absence of ruptures or fragile regions), flexibility, ease of detachment of the support and handling, without the need to add adjuvant to its formation. In addition, they presented uniformity in thickness, high light barrier and medium water vapor barrier. Thus, it can be concluded that mucilage is a potential product to be used in the cosmetic, pharmaceutical and food industries.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68272608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

GUIA DETALHADO PARA MONTAGEM PRÓPRIA DE IMPRESSORAS 3D 自己组装3D打印机的详细指南

IF 0.8 4区化学

Quimica Nova Pub Date : 2023-10-09 DOI: 10.21577/0100-4042.20230057

M. Pereira, R. Quero, Dosil Pereira De Jesus, Juliano Bonacin

引用次数: 0

UMA ANÁLISE DO PROCESSO DE ELABORAÇÃO DE PERGUNTAS PRODUZIDAS POR LICENCIANDOS EM QUÍMICA A PARTIR DA LITERATURA DE DIVULGAÇÃO CIENTÍFICA 对化学本科生提出的问题的阐述过程进行了分析，并从科学文献中进行了分析

IF 0.8 4区化学

Quimica Nova Pub Date : 2023-10-09 DOI: 10.21577/0100-4042.20230047

Pedro Paulo Da Silva, Flávio Schifino, C. Sirtori, C. Passos, N. Simon

{"title":"UMA ANÁLISE DO PROCESSO DE ELABORAÇÃO DE PERGUNTAS PRODUZIDAS POR LICENCIANDOS EM QUÍMICA A PARTIR DA LITERATURA DE DIVULGAÇÃO CIENTÍFICA","authors":"Pedro Paulo Da Silva, Flávio Schifino, C. Sirtori, C. Passos, N. Simon","doi":"10.21577/0100-4042.20230047","DOIUrl":"https://doi.org/10.21577/0100-4042.20230047","url":null,"abstract":"AN ANALYSIS OF THE PROCESS OF DEVELOPING QUESTIONS PRODUCED BY CHEMISTRY STUDENTS IN A TEACHING PROGRAM BASED ON SCIENTIFIC COMMUNICATION LITERATURE. The objective of the present investigation was to evaluate the use of scientific dissemination literature (SDL) in the process of formulating questions developed by chemistry students in a Teaching Program in Chemistry. To this end, the book entitled The Disappearing Spoon was analyzed in terms of categories referring to format and content, while the 18 questions produced by these students about the chapters read were analyzed in terms of presupposition and request. The investigation was carried out with 16 undergraduates who were taking a theoretical course on “Introduction to Chemistry”, as part of the Teaching Program in Chemistry. According to the analysis carried out, some particularities of format, such as the scarcity of visual resources, the autonomous structure of the chapters and the language, may have influenced the elaborated presentations. It is interesting to note that almost half of the questions produced were of an investigative nature, demonstrating the potential of SDL to stimulate high cognitive skills. In addition, the questions with investigative requests were mostly opinion questions, which may have been motivated by characteristics of the text read, such as the content with a controversial approach used by the author, when reporting on some aspects of scientific activity.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A BIOQUÍMICA POR TRÁS DA COVID-19: DESENVOLVIMENTO E APLICAÇÃO DE WEBQUEST DIRECIONADA AO ENSINO REMOTO EMERGENCIAL COVID-19背后的生物化学:针对紧急远程学习的WEBQUEST开发和应用

IF 0.8 4区化学

Quimica Nova Pub Date : 2023-10-09 DOI: 10.21577/0100-4042.20230044

N. Silva, Carolina Sotério, Fernanda Canduri, S. Queiroz

引用次数: 0

ATR-FTIR AND UV-VIS AS TECHNIQUES FOR METHANOL ANALYSIS IN BIODIESEL-WASHING WASTEWATER after - ftir和uv-vis技术在生物柴油洗涤废水中甲醇分析中的应用

IF 0.8 4区化学

Quimica Nova Pub Date : 2023-08-28 DOI: 10.21577/0100-4042.20230041

{"title":"ATR-FTIR AND UV-VIS AS TECHNIQUES FOR METHANOL ANALYSIS IN BIODIESEL-WASHING WASTEWATER","authors":"","doi":"10.21577/0100-4042.20230041","DOIUrl":"https://doi.org/10.21577/0100-4042.20230041","url":null,"abstract":"Methanol present in wastewater from the biodiesel industry can become an atmospheric pollutant and an environmental liability of effluents. This article proposes the development and performance evaluation of two spectroscopic methods, ATR-FTIR and UV-Vis, to identify and quantify methanol in aqueous media. The results of both ways exhibited remarkable linear detection, with a coefficient of determination (r2) > 0.99, wide working range, and relative standard deviation (RSD) < 12%. In the ATR-FTIR method, the detection and quantification limits were 0.064 and 0.128% m V-1, respectively. The UV-Vis method presented lower limits (0.005 and 0.008% m V-1, respectively). Finally, the methods were successfully applied to quickly and sensitively quantify the methanol present in wastewater from biodiesel-washing in a wide concentration range of 0.008-0.641% m V-1. Therefore, we evidenced the feasibility of spectroscopic methods in quality control for identifying and quantifying methanol in aqueous solution, with potential for application in biodiesel production industries and research laboratories. Mainly by ATR-FTIR, in the region of 1300-900 cm-1, as it proved to be more environmentally friendly, faster, and cheaper than the GC-FID method.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

BOAS PRÁTICAS SUSTENTÁVEIS DE GESTÃO DE RESÍDUOS QUÍMICOS EM INSTITUIÇÕES PÚBLICAS DE ENSINO SUPERIOR 公立高等教育机构化学废物管理的可持续良好做法

IF 0.8 4区化学

Quimica Nova Pub Date : 2023-08-28 DOI: 10.21577/0100-4042.20230034

Marcus Arantes, W. Günther

引用次数: 0