Viscosity and Excess Viscosity of Dilute Aqueous Solutions of Ethylenediamine,Trimethylenediamine and N,N -Dimethyltrimethylenediamine

Viscosities of the systems, water (W) + ethylenediamine (ED), W + trimethylenediamine (TMD) and W + N , N -dimethyltrimethylenediamine (DMTMD) were determined from 303.15 to 323.15 K and in the composition range, 0 h X 2 h 0.45, where X 2 is the mole fraction of solutes. On addition of the solutes to water the viscosities increase sharply, pass through maxima and then decline; the heights of maxima vary as, W + DMTMD > W + TMD > W + ED. The maxima occur at X 2 0.225, 0.300 and 0.325 for the systems, W + DMTMD, W + TMD and W + ED, respectively. The position of maximum of a particular system remains unchanged with temperature. The rapidly ascending part of viscosity curves is accounted for by the combined effect of hydrophobic hydration and hydrophilic effect, while the declining part of the curves is thought to be due to predominance of hydrophobic interaction.     

N,N-二甲基甲酰胺在不同浓度氯化钠水溶液中的稀释过程热力学

应用等温流动微量热法测定了298.15 K时N,N-二甲基甲酰胺(DMF)在纯水及不同浓度氯化钠水溶液中的稀释焓, 根据McMillan-Mayer理论计算得到各级同系焓相互作用系数. 结果表明, DMF在纯水及氯化钠水溶液中的焓对相互作用系数h2均为正值, 并且随着氯化钠浓度的增加, h2的值逐渐增大. 根据溶质-溶质相互作用和溶质-溶剂相互作用对结果进行了解释.     

对甲氧基苯甲醛与N,N-二甲基甲酰胺密度黏度的测定与关联

在常压,298.15K~353.15K条件下,采用U形振动管密度计测定了对甲氧基苯甲醛-N,N-二甲基甲酰胺二元物系的密度,采用乌氏黏度计测定其黏度;并由密度和黏度数据分别计算了该二元物系超额摩尔体积VE和混合黏度的变化Δη.在不同的温度和组成下超额摩尔体积和混合黏度的变化都是负值,同时对不同温度下的超额摩尔体积与组成的关系以及混合黏度的变化与组成的关系都按Redlich-Kister方程进行了拟合,计算值与实验值的最大标准偏差小于7%.     

Electrochemistry of Europium in Aqueous and Aqueous Formamide Solutions

Abstract

The electrochemical behavior of the system Eu(III)/Eu(II) in aqueous formamide solutions was studied by current reversal chronopotentiometry at a mercury pool electrode, in 1 M NaClO₄ The results indicate that double layer effects must be considered rather that ion solvation effects when explaining the influence of formamide on the Eu(III)/Eu(II) electrode reaction.     

1,3,3-三硝基氮杂环丁烷在乙酸乙酯和N,N-二甲基甲酰胺中的溶解行为

在常压、298.15 K条件下, 用RD496-2000微热量仪分别测量了1,3,3-三硝基氮杂环丁烷(TNAZ)在乙酸乙酯(EA)和N,N-二甲基甲酰胺(DMF)中的溶解焓. 得到了TNAZ在不同溶剂中的微分溶解热和积分溶解热. 建立了热量与溶质的量之间的关系式. 对TNAZ, 得到了在乙酸乙酯中描述溶解过程的动力学方程为dα/dt=10-7.26(1-α)0.88; 在N,N-二甲基甲酰胺中, 描述溶解过程的动力学方程为dα/dt=10-7.21(1-α)0.66.     

二氧化碳与二甲胺催化合成N,N-二甲基甲酰胺

二氧化碳(CO₂)是大气中主要温室气体之一,也是丰富、安全、可再生的碳一资源。将CO₂催化转化为高附加值化学品不仅能改善人类长期依赖化石资源的困境,还能有效减少CO₂排放,助力实现“碳达峰、碳中和”这一“双碳”目标。N,N-二甲基甲酰胺(DMF)是一种年产百万吨级的平台化合物,是优良的溶剂以及重要的化工中间体。因此,以CO₂作为羰源,通过高效催化体系的构建实现CO₂与二甲胺反应合成DMF具有重要意义。本文分别从还原剂、催化体系和反应机理等角度综述了这一领域近年来的研究进展。最后,对CO₂合成DMF催化过程中所面临的问题和未来的发展方向进行了探讨和展望。     

N,N-二甲基甲酰胺及其降解产物分析方法研究进展

随着N,N-二甲基甲酰胺(DMF)应用行业的不断拓宽及使用量的增加导致其被动暴露人群数量大且持续增加。近年来,DMF对人体健康的潜在危害引起了相关领域广大科技工作者的广泛关注。如何有效地分离分析DMF及其降解产物是研究其迁移、转化等环境行为及生物毒性的首要问题。对近年来DMF及其降解产物的色谱、质谱分析方法研究进展及其特点进行了综述,并且分析了其发展趋势。     

A Journey from June 2018 to October 2021 with N,N-Dimethylformamide and N,N-Dimethylacetamide as Reactants

A rich array of reactions occur using N,N-dimethylformamide (DMF) or N,N-dimethylacetamide (DMAc) as reactants, these two amides being able to deliver their own H, C, N, and O atoms for the synthesis of a variety of compounds. This account highlights the literature published since June 2018, completing previous reviews by the author.     

Viscosity of aqueous solutions of 2-propyne-1-ol, 2-methyl-3-butyne-2-ol and 3-butene-2-ol

Viscosities of aqueous solutions of 2-propyne-1-ol (propargyl alcohol), 2-methyl-3-butyne-2-ol and 3-butene-2-ol have been measured at temperatures 308.15, 313.15, 318.15, 323.15 and 328.15?K over the entire composition range. Viscosity of the aqueous solutions of 2-methyl-3-butyne-2-ol and 3-butene-2-ol increases up to a maximum value and then starts decreasing almost linearly as the mole fraction of alcohol increases. 2-Methyl-3-butyne-2-ol + water and 3-butene-2-ol + water systems exhibit maxima around 0.5 and 0.2 mole fraction, respectively. Conversely, 2-propyne-1-ol + water system shows a rapid initial increase in viscosity up to 0.3 mole fraction followed by a slow steady increase as the mole fraction of alcohol increases to its pure state. Plots of excess viscosities against mole fraction of organic solutes for all the systems exhibit a sharp increase in η ^E to reach a well defined maxima, after which the curves show a descending trend. The variations of viscosity and excess viscosity with the composition of the mixtures have been interpreted in terms of hydrophobic and hydrophilic interactions between the species forming the mixtures.     

双核钴卟啉/DMF体系的吸氧热力学研究

关于单核金属卟啉体系的吸氧热力学已有广泛的研究．七十年代末至八十年代初，报导了一类面对面双时批双核钴的双氧配合物，根据ESR谱，认为存在Co-O-Co的超氧桥式结构．关于Co：02＝1：1的双核钴双卟啉配合物的吸氧热力学，迄今未见报导．本工作用电子光谱法研究了一种由十个碳原子的脂肪二酰胺链连接两个四苯基卟啉的双核钴（Ⅱ）配合物在DMF溶液中与双氧的可逆结合作用，测定了吸氧热力学数据，用ESR谱法研究了钻离子与双氧的结合方式．1实验部分五·五样品和试剂双核钴（11）双环叶琳，CO。diTPP（diAMCs）的合成见文献间，其…     

Volumetric and Viscometric Properties of Aqueous Solutions of N-Methylformamide, 1,2-Diaminopropane and 2-Methylpropane-2-ol

Density and viscosity of aqueous solutions of N-methylformamide (NMF), 1,2-diaminopropane (DAP) and 2-methylpropane-2-ol (MPL) have been measured precisely over the entire composition range (i.e., 1 ≥ x ₂ ≥ 0) at five equidistant temperatures ranging from 298.15 to 318.15 K. Excess molar volume (V^E _m ) and excess viscosity (η ^E ) have been calculated from measured density and viscosity data, respectively. Excess molar volume and excess viscosity have been fitted by the least squares method to the four parameters Redlich-Kister equation. The results have been interpreted on the basis of (i) interstitial incorporation, (ii) breakdown of the structure of pure liquids, (iii) hydrophobic hydration, (iv) hydrophobic interaction and (v) association between dissimilar liquids.     

甲酰胺与肌醇在氯化钠水溶液中的焓相互作用

应用等温流动微量热法测定298.15 K时甲酰胺与肌醇分子在不同浓度氯化钠水溶液中的混合过程焓变及其稀释焓, 根据McMillan-Mayer理论关联得到各级异系焓相互作用系数(h_xy, h_xxy及h_xyy). 结果表明, 甲酰胺与肌醇分子在氯化钠水溶液中的异系焓对相互作用系数h_xy均为负值, 并且随着氯化钠浓度的增加, h_xy的绝对值逐渐减小.     

Viscosities of Aqueous Solutions of Dimethylsulfoxide, 1,4-Dioxane and Tetrahydrofuran

Abstract

Viscosities of the systems, water(W) + dimethylsulfoxide(DMSO), W + 1,4-dioxane (DXN) and W + tetrahydrofuran(THF), are measured at temperatures ranging from 303.15–323.15K. Viscosities and excess viscosities are plotted against the mole fraction of the organic solutes. On addition of solutes to water, viscosities first increase rapidly, pass through maxima and then decline continuously until the pure state of solutes is reached. Excess viscosities are found to be positive and large in magnitude and their curves are similar to those of the viscosity curves. The ascending part of the viscosity curves in the water-rich region is accounted for by both the hydrophobic effect of forming cage structures around solutes and the hydrophilic effect forming H-bonds between water and organic solutes. The descending part of the viscosity curves is explained by the continuous destruction of cages formed. The maxima are thought to be due to competing processes of formation and destruction of cage structures.     

Volumetric, Ultrasonic and Transport Properties of Binary Liquid Mixtures Containing Dimethyl Formamide at 303.15 K

Excess volumes （v^E）, ultrasonic velocities （u）, isentropic compressibility （△Ks） and viscosities （η） for the binary mixtures of dimethyl formamide （DMF） with 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,2,4-trichlorobenzene, o-chlorotoluene, m-chlorotoluene, p-chlorotoluene, o-nitrotoluene and m-nitrotoluene at 303.15 K were studied. Excess volume data exhibit an inversion in sign for the mixtures of dimethyl formamide with 1,2- and 1,3-dichlorobenzenes and the property is completely positive over the entire composition range for the mixtures of dimethyl formamide with 1,2,4-trichlorobenzene, o-nitrotoluene and m-nitrotoluene. On the other hand, the quantity is negative for the mixtures of dimethyl formamide with chlorotoluenes. Isentropic compressibility （Ks） has been computed for the same systems from precise sound velocity and density data. Further, deviation of isentropic com- pressibility （△Ks） from ideal behavior was also calculated. AKs values are negative over the entire volume fraction range in all the binary mixtures. The experimental sound velocity data were analysed in terms of Free Length Theory （FLT） and Collision Factor Theory （CFT）. The viscosity data were analysed on the basis of corresponding state approach. The measured data were discussed on the basis of intermolecular interactions between unlike molecules.     

Solvation of bivalent transition metalcations. II. Heats of transfer of metal perchlorates between water and several amides

Heats of solution of acetonitrile, solvated or hydrated perchlorates, Mn(ClO₄)₂·6AN, Co(ClO₄)₂·6AN, Ni(ClO₄)₂·6AN, Cu(ClO₄)₂·4AN, Cu(ClO₄)₂·6H₂O, Zn(ClO₄)₂·6AN, and Zn(ClO₄)₂·6H₂O have been determined in NMF, DMF, DMA, and water. Complete or almost complete exchange of AN and water molecules in amides is inferred from the visible spectra determinations. The heats of transfer of perchlorate anion from water to DMA and NMF have been obtained from separately determined heats of solution of NaBPh₄, AsPH₄Cl·H₂O, NaClO₄, NaCl, and SiPh₄ in the respective solvents. The heats of transfer of cations from water to amides have been determined from the above data and the heats of solvation of cations using literature data for the heats of hydration.     

Structure and stability of hydrogen fluoride complexes with N,N-dimethylformamide

The structure, stability, and paths of formation of 11 (HF)_m(DMF)_n heterocomplexes (m = 1–4, n = 1, 2) were studied in terms of the B3LYP/6-31++G(d, p) density functional calculation. The results of this calculation suggest that: a) addition of hydrogen fluoride molecules to the (HF)_mDMF cyclic fragment is the basic tendency in complex formation in the HF-DMF system; b) data about the structure and properties of stable molecular forms that prevail in N,N-dimethylformamide solutions of hydrogen fluoride can be obtained by quantum chemical calculations for (HF)_mDMF complexes (m = 5–10).     

丙氨酸在葡萄糖和蔗糖水溶液中的体积性质

利用精密数字密度计分别测定了丙氨酸在不同组成的葡萄糖和蔗糖水溶液中的密度,计算了丙氨酸的表观摩尔体积、极限偏摩尔体积和理论水化数,根据结构水合作用模型讨论了迁移偏摩尔体积的变化规律,并与乙二醇-水和丙三醇-水等多羟基体系作了比较.结果表明,丙氨酸分子在多羟基化合物-水体系中体积效应的大小与多羟基化合物所含OH基数目有关.     

丝氨酸在蔗糖水溶液中的稀释焓

利用LKB 2277生物活性检测仪分别测定了298.15 K时丝氨酸在不同组成的蔗糖水溶液中的稀释焓, 利用McMillan-Mayer理论,计算了丝氨酸在不同组成的蔗糖水溶液中的焓对相互作用系数,并与其在葡萄糖水溶液中的焓对相互作用系数h2进行了比较.结果表明,丝氨酸在蔗糖和葡萄糖水溶液中的焓对相互作用系数h2都是负值,并且随着糖浓度的增加,h2系数的绝对值逐渐减少.根据溶质-溶质相互作用和溶质-溶剂相互作用对结果进行了解释.     

Solvent‐Polymeric ISEs Tailored for Measurements in Solutions Containing Tetrabutylammonium,Cesium, and Calcium Ions

Ion‐selective electrodes are described, with membranes tailored for measurements of tetrabutylammonium ions in aqueous and formamide solutions, and for measurements of cesium and calcium ions in the presence of tetrabutylammonium. It is shown that reliable measurements of cesium ions are possible when a correction is introduced for interference from tetrabutylammonium, using Nikolsky selectivity coefficient. A novel membrane composition is described which ensures high selectivity to calcium ions over tetrabutylammonium.