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Modeling of transport properties of binary mixtures including ionic liquids based on their experimental estimation 基于实验估计的含离子液体二元混合物输运性质建模
IF 0.8 Pub Date : 2022-01-01 DOI: 10.2478/acs-2022-0014
P. Steltenpohl, Anna Holečková, E. Graczová
Abstract Transport properties of selected imidazolium ionic liquids (1-ethyl-3-methylimidazolium acetate, [emim][ac], and 1-butyl-3-methylimidazolium trifluoromethanesulfonate, [bmim][triflate]) as well as of binary mixtures of these ILs with water and ethanol were estimated experimentally. Density data were obtained within the temperature range of 293.15—333.15 K and used for the excess molar volume calculations. For the binary mixtures comprising selected ionic liquids and water/ethanol, partial molar volumes of mixture components were computed and the excess molar volume variation with the mixture composition was correlated using the Redlich-Kister equation. Dependence of viscosity on the binary mixture composition and temperature was described using the Jouyban-Acree model. These data form a base for the assessment of OPEX connected with transportation of mixtures containing these ionic liquids.
摘要实验估计了所选咪唑鎓离子液体(1-乙基-3-甲基咪唑鎓乙酸酯,[emim][ac]和1-丁基-3-甲基咪唑三氟甲磺酸酯,[bmim][trifluate])以及这些离子液体与水和乙醇的二元混合物的输运性质。密度数据是在293.15--333.15K的温度范围内获得的,用于过量摩尔体积的计算。对于包含所选离子液体和水/乙醇的二元混合物,计算混合物组分的偏摩尔体积,并使用Redlich-Kister方程将过量摩尔体积随混合物组成的变化关联起来。使用Jouyban-Acree模型描述了粘度对二元混合物组成和温度的依赖性。这些数据为评估与含有这些离子液体的混合物的运输相关的运营成本奠定了基础。
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引用次数: 1
The role of deep eutectic solvents in the production of cellulose nanomaterials from biomass 深度共晶溶剂在生物质制备纤维素纳米材料中的作用
IF 0.8 Pub Date : 2022-01-01 DOI: 10.2478/acs-2022-0008
V. Jančíková, M. Jablonský
Abstract In recent years, the demand for environment-friendly products has been on an increasing trend among researchers and industry for sustainable development. Deep eutectic solvents are green solvents which, due to their properties (biodegradability, recyclability, low cost, availability, easy preparation, low toxicity, chemical and thermal stability), can be used in various fields such as polymer chemistry, which includes nanocellulose isolation and polysaccharides processing. Several studies have illustrated the effectiveness of using deep eutectic solvents instead of the conventional reaction system to produce and disperse nanomaterials. This work summarizes the use of deep eutectic solvents in the isolation of cellulosic nanomaterials from different types of biomass. Deep eutectic solvents demonstrate high effectiveness in swelling lignocellulosic biomass and producing cellulose nanomaterials. Overall, deep eutectics solvents represent an innovative and effective pretreatment process for the fractionation of raw cellulose-containing fibres to promote subsequent isolation of nanomaterials made from cellulose.
近年来,研究人员和可持续发展行业对环境友好型产品的需求日益增长。深共晶溶剂是一种绿色溶剂,由于其具有生物降解性、可回收性、低成本、易获得性、制备简单、低毒、化学和热稳定性等特性,可用于高分子化学的各个领域,包括纳米纤维素的分离和多糖的加工。一些研究表明,使用深度共晶溶剂代替传统的反应体系来生产和分散纳米材料是有效的。本文综述了深度共晶溶剂在从不同类型生物质中分离纤维素纳米材料中的应用。深共晶溶剂在溶胀木质纤维素生物质和生产纤维素纳米材料方面表现出很高的效率。总的来说,深度共晶溶剂代表了一种创新和有效的预处理工艺,用于分离含纤维素的原料纤维,以促进纤维素制成的纳米材料的后续分离。
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引用次数: 5
Analytical methods for pesticide residues determination in propolis and propolis-based products 蜂胶和蜂胶基产品中农药残留测定的分析方法
IF 0.8 Pub Date : 2022-01-01 DOI: 10.2478/acs-2022-0012
I. Blažková, J. Hrouzek, Agneša Szarka, Tamara Pócsová, S. Hrouzková
Abstract As a result of massive bee deaths in recent years, beekeeping is raising concerns about the presence of pesticides in propolis which is considered as a safe product. The paper is focused on the analysis of bee propolis and propolis-based products using various chromatographic techniques using mass spectrometry detection predominantly. An important part of the work is an overview concerning methods of sample preparation, extraction, and purification of extracts, followed by separation and detection techniques. Positive findings of contaminants and their concentrations in propolis samples and propolis products were evaluated. Sorption based techniques such as matrix solid phase dispersion and solvent-based extraction techniques are frequently applied for propolis analysis in connection with chromatographic techniques. Liquid-based extractions, such as the QuEChERS extraction technique (Quick, Easy, Cheap, Effective, Rugged, Safe), combine extraction by solvent with several ways of extract cleaning using combinations of salts and sorbents, primary secondary amine, MgSO4, NaCl, graphitized carbon, EMR-lipid, florisil, or octadecylsilane-modified silica gel. Other extraction techniques were reviewed. The most significant problem to be considered in pesticides detection is the topic of matrix effects, which have to be solved for each sample analysis with special care.
近年来,由于蜜蜂大量死亡,养蜂人对蜂胶中农药的存在感到担忧,蜂胶被认为是一种安全的产品。本文主要介绍了蜂胶和蜂胶基产品的各种色谱分析技术,以质谱检测为主。该工作的一个重要部分是概述了样品制备,提取和提取纯化的方法,其次是分离和检测技术。对蜂胶样品和蜂胶制品中的污染物及其浓度进行了评估。以吸附为基础的技术,如基质固相分散和溶剂萃取技术,经常与色谱技术相结合,用于蜂胶分析。液体萃取,如QuEChERS萃取技术(快速、简单、廉价、有效、坚固、安全),结合溶剂萃取和几种萃取清洗方法,使用盐和吸附剂、仲胺、MgSO4、NaCl、石墨化碳、emr -脂质、florisil或十八烷基硅烷改性硅胶的组合。对其他提取技术进行了综述。在农药检测中需要考虑的最重要的问题是矩阵效应,这是每个样品分析都必须特别注意解决的问题。
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引用次数: 3
Thermodynamic characterization of acid cryolite systems 酸性冰晶石体系的热力学表征
IF 0.8 Pub Date : 2022-01-01 DOI: 10.2478/acs-2022-0011
Michaela Benköová, E. Mališová, J. Híveš
Abstract Measuring of the electromotive force in molten system is used to characterize thermodynamic properties of the system at equilibrium. Values of the electromotive force are very important for the determination of activity and standard electrode potential. Investigation of the electromotive force of Al + TiB2 and Al-Al cell was the main aim of this work leading to the characterization of acid cryolite systems. The measurements were realized using a molten aluminum electrode and the electromotive force of an electrochemical cell was investigated in electrolytes at various molar ratios (NaF/AlF3) at equilibrium. Thermodynamic properties were measured in acid cryolite melts at three different temperatures: 800 °C, 900 °C, and 1000 °C, for all experiments.
摘要通过测量熔融体系中的电动势来表征系统在平衡状态下的热力学性质。电动势的值对于活性和标准电极电势的测定非常重要。本工作的主要目的是研究Al+TiB2和Al-Al电池的电动势,从而对酸性冰晶石系统进行表征。使用熔融铝电极实现测量,并在平衡时在不同摩尔比(NaF/AlF3)的电解质中研究电化学电池的电动势。在酸性冰晶石熔体中,在800°C、900°C和1000°C三种不同温度下测量了所有实验的热力学性质。
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引用次数: 0
Binary mixtures containing imidazolium ionic liquids: properties measurement 含有咪唑类离子液体的二元混合物:性质测量
IF 0.8 Pub Date : 2022-01-01 DOI: 10.2478/acs-2022-0003
P. Steltenpohl, E. Graczová
Abstract Densities and transport properties (dynamic viscosity) of pure imidazolium ionic liquids 1-butyl-3-methylimidazolium acetate and 1-butyl-3-methylimidazolium dicyanamide and their binary mixtures with water and ethanol were measured within the temperature range of 293.15—333.15 K. Obtained experimental data were used to calculate excess molar volume and viscosity deviation. For the chosen binary mixtures, variations of excess molar volume, partial molar volumes of mixture components and of the viscosity deviation with the binary mixture composition were correlated using the Redlich-Kister equation. In addition, variation of viscosity with the binary mixture composition and temperature was fitted using the Jouyban-Acree model.
摘要在293.15--333.15K的温度范围内,测量了纯咪唑离子液体1-丁基-3-甲基咪唑鎓乙酸酯和1-丁基-3-乙基咪唑鎓双氰胺及其与水和乙醇的二元混合物的密度和传输特性(动态粘度)。所得实验数据用于计算过量摩尔体积和粘度偏差。对于所选择的二元混合物,使用Redlich-Kister方程将过量摩尔体积、混合物组分的偏摩尔体积以及粘度偏差与二元混合物组成的变化关联起来。此外,使用Jouyban-Acree模型拟合了粘度随二元混合物组成和温度的变化。
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引用次数: 2
Thermochemistry of antioxidant action of isoflavones and their deprotonated forms in aqueous solution: hydrogen or electron transfer? 异黄酮的抗氧化作用及其在水溶液中的去质子化形式的热化学:氢或电子转移?
IF 0.8 Pub Date : 2022-01-01 DOI: 10.2478/acs-2022-0004
Monika Biela, A. Kleinová, E. Klein
Abstract Isoflavones possessing several weak acidic hydroxyl groups can undergo successive deprotonations in aqueous solutions. Therefore, their antioxidant properties cannot be ascribed only to the neutral forms but also to corresponding phenoxide anions. It was already confirmed that isoflavones prefer the formation of dianions in aqueous solution. For eight isoflavones and their preferred (poly)deprotonated forms, thermochemistry of hydrogen atom transfer and electron abstraction was studied in terms of corresponding reaction enthalpies, i.e., O—H bond dissociation enthalpies and ionization potentials. Our results clearly indicate that the increase in negative charge causes significant drop in ionization potential and bond dissociation enthalpy. On the other hand, proton affinities show the opposite trend. Thus, it is unfeasible to find a generally valid trend for dianions — corresponding reaction enthalpies strongly depend on the structure of isoflavone, especially on the number/positions of OH groups.
具有几个弱酸性羟基的异黄酮在水溶液中可发生连续的去质子化。因此,它们的抗氧化性能不能仅仅归因于中性形式,也归因于相应的苯氧阴离子。已经证实异黄酮在水溶液中倾向于形成阴离子。对8种异黄酮及其优选的(聚)去质子形式,根据相应的反应焓,即O-H键解离焓和电离势,研究了氢原子转移和电子抽离的热化学性质。我们的结果清楚地表明,负电荷的增加导致电离势和键解离焓的显著下降。另一方面,质子的亲合力则呈现相反的趋势。因此,寻找一个普遍有效的趋势是不可能的,相应的反应焓强烈地依赖于异黄酮的结构,特别是OH基团的数目/位置。
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引用次数: 0
Nanotextiles — materials suitable for respiratory tract protection but a source of nano- and microplastic particles in the environment 纳米纺织品——适用于呼吸道保护的材料,但也是环境中纳米和微塑料颗粒的来源
IF 0.8 Pub Date : 2022-01-01 DOI: 10.2478/acs-2022-0006
Petra Roupcová, H. Kubátová, Katerina Batrlova, K. Klouda
Abstract The paper deals with the formation of nanomaterials (nanoparticles and nanofibers) in the manufacture and use of respiratory protective equipment. It focuses mainly on processes leading to the release of nanoplastics into the workplace and the environment. Based on selected properties of materials used for the manufacture of protective equipment, their stability in the environment is revealed. The paper demonstrates the impact on the environment considering semichronic phytotoxicity of nanoplastics.
摘要本文论述了纳米材料(纳米粒子和纳米纤维)在呼吸防护设备的制造和使用中的形成。它主要关注导致纳米塑料释放到工作场所和环境中的过程。根据防护装备材料的选择性能,揭示了它们在环境中的稳定性。本文从纳米塑料的半时性植物毒性角度论证了其对环境的影响。
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引用次数: 2
Pre-treatment of lignocellulosic materials by enzymatic mixture to enhance biogas production 用酶混合物预处理木质纤维素材料以提高沼气产量
IF 0.8 Pub Date : 2022-01-01 DOI: 10.2478/acs-2022-0005
Barbora Jankovičová, M. Hutňan, Marianna Czӧlderová, J. Barbušová
Abstract The aim of this study was to evaluate the effect of an enzymatic mixture on the increase of biogas production from lignocellulosic materials as rapeseed straw, maize waste, and wheat straw. For efficient application of the enzymatic mixture, conditions of its use were optimized regarding 50 °C, pH 7 and an enzyme dose of 0.25 % w/v. Biogas potential test confirmed positive effect of the enzymatic mixture on anaerobic digestion of already thermally and alkali pre-treated lignocellulosic materials, as significantly higher biogas production was observed after the enzymatic mixture addition for all monitored substrates. Addition of the enzymatic mixture to the most used substrate at biogas plants — maize silage, had also positive effect on biogas production during the biogas potential test. This fact was not proven during long-term operations of the reactors as the values of total cumulative biogas productions for the whole monitored period from reactors for anaerobic digestion of maize silage with and without addition of enzymatic mixture did not differ significantly.
摘要本研究的目的是评价一种酶混合物对增加油菜籽秸秆、玉米秸秆和小麦秸秆等木质纤维素材料的沼气产量的影响。为了有效地应用酶混合物,优化了其使用条件,温度为50°C, pH为7,酶剂量为0.25% w/v。沼气电位测试证实了酶混合物对已经经过热处理和碱预处理的木质纤维素材料厌氧消化的积极影响,因为在所有监测的底物中添加酶混合物后,观察到明显更高的沼气产量。在沼气池电位试验中,在沼气池中使用最多的基质——玉米青贮中添加酶混合料对沼气池的产气量也有积极的影响。这一事实在反应器的长期运行中没有得到证实,因为在整个监测期间,添加酶混合物和不添加酶混合物的玉米青贮厌氧消化反应器的总累积沼气产量没有显著差异。
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引用次数: 0
On the energetics of radical adduct formation of OH• with phenol analogs and aniline 苯酚类似物和苯胺形成OH•自由基加合物的热力学研究
IF 0.8 Pub Date : 2022-01-01 DOI: 10.2478/acs-2022-0002
Dagmar Štellerová, Vladimír Lukes
Abstract Theoretical studies on aniline, phenol, benzenethiol, benzeneselenol, and their corresponding adducts with hydroxyl radical in possible positions on a hydrocarbon ring are presented. Bond dissociation enthalpies, related to radical scavenging of primary antioxidants, were calculated using the M06–2X/6–311+G** method. Calculated data were compared with available experimental data. Preferable homolytic bond dissociation of the presented molecules with OH• through functional groups X—OH followed by the m–OH ones has been confirmed. The highest antioxidant activity among the investigated positions is predicted for benzeneselenol. Also, the formation of non-covalent van der Waals structures has been shown as important in radical scavenging.
摘要本文对苯胺、苯酚、苯乙醇和苯乙醇和相应的羟基加合物在烃环上的可能位置进行了理论研究。用M06-2X / 6-311 +G**方法计算了与自由基清除有关的键解离焓。计算数据与现有实验数据进行了比较。所提分子通过X-OH官能团和m-OH官能团较好地与OH•均解键。预测苯二烯醇的抗氧化活性最高。此外,非共价范德华结构的形成已被证明在自由基清除中很重要。
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引用次数: 0
DFT studies of camptothecins cytotoxicity III: camptothecin, irinotecan and SN-38 喜树碱细胞毒性的DFT研究III:喜树碱、伊立替康和SN-38
IF 0.8 Pub Date : 2022-01-01 DOI: 10.2139/ssrn.4083390
M. Štekláč, M. Breza
Abstract Geometries of camptothecin, irinotecan, SN-38, and of their hypothetical Cu(II) complexes were optimized at the B3LYP/6-311G* level of theory. Their electron structure, evaluated in terms of Mulliken population analysis and Quantum Theory of Atoms-in-Molecule, was subsequently related to in vitro cytotoxicity. Electron density transfer from the relevant active sites to Cu decreases in the sequence irinotecan > SN-38 > camptothecin. The absolute values of their metal-ligand interaction energies exhibit the same trend. Discrepancy with the least relative in vitro cytotoxicity of irinotecan can be explained by differences in its pharmacokinetics.
摘要对喜树碱、伊立替康、SN-38及其假设的Cu(II)配合物的几何结构在B3LYP/6-311G*水平上进行了理论优化。它们的电子结构,根据Mulliken种群分析和分子原子量子理论进行评估,随后与体外细胞毒性有关。从相关活性位点到Cu的电子密度转移在irinotecan > SN-38 >喜树碱序列中减少。它们的金属-配体相互作用能的绝对值也表现出相同的趋势。与伊立替康相对最小体外细胞毒性的差异可以通过其药代动力学的差异来解释。
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引用次数: 1
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Acta Chimica Slovaca
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