Ultrasonic velocities and densities of alkyl substituted ammonium perchlorates-RNH3ClO4, where R is methyl (Me), ethyl (Et),n-propyl (Pr),n-butyl (Bu),n-hexyl (Hx) and n-octyl (Oc), have been measured in the concentration range 0.03–0.28 mol·kg−1 in binary mixtures of acetonitrile (AN) and N,N-dimethylacetamide (DMA) containing 0, 20, 40, 60, 80 and 100 mol% DMA at temperatures 298–328 K in 10 K intervals, using an Anton Paar density and sound velocity meter (DSA 5000 M). The experimental data of ultrasonic velocities and densities have been used for calculating isentropic compressibilities (KS\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$K_{{S}}$$\end{document}) and apparent molal isentropic compressibilities (KS,ϕ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$K_{{{S,}\phi }}$$\end{document}). Limiting apparent molal isentropic compressibilities (KS,ϕo\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$K_{{{S,}\phi }}^{{\text{o}}}$$\end{document}) for all the electrolytes have been evaluated from KS,ϕ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$K_{{{S,}\phi }}$$\end{document} against m1/2 plots and split into contributions of individual ion (KS,ϕ,±o\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$K_{{{S,}\phi , \pm }}^{{\text{o}}}$$\end{document}). The variation of KS,ϕ,±o\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$K_{{{S,}\phi , \pm }}^{{\text{o}}}$$\end{document} values with solvent composition shows preferential solvation of alkylammonium (RNH3+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{RNH}}_{3}^{ + }$$\end{document}) ions by DMA in the AN rich region and by AN in the DMA rich region. The extent of solvation of the alkylammonium ions, at all studied temperatures, was found to increase with decreasing alkyl chain length; that is OcNH3+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{OcNH}}_{3}^{ + }$$\end{document} < HxNH3+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{HxNH}}_{3}^{ + }$$\end{document} < BuNH3+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{BuNH}}_{3}^{ + }$$\end{document} < PrNH3+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{PrNH}}_{3}^{ + }$$\end{document} < EtNH3+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{EtNH}}_{3}^{ + }$$\end{document} < MeNH3+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{MeNH}}_{3}^{ + }$$\end{document}. KS,ϕ,±o\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$K_{{{S,}\phi , \pm }}^{{\text{o}}}$$\end{document} values for all RNH3+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{RNH}}_{3}^{ + }$$\end{document} ions increase with increasing temperature, indicating a decrease in the solvation of the ions with increasing temperature.

中文翻译：

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乙腈和 N,N-二甲基乙酰胺二元混合物中单烷基铵盐在不同温度和大气压下的超声速度和等熵压缩性研究

超声波速度和密度的实验数据已用于计算等熵压缩率 (KS\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$K_{{S}}$$\end{document}）和明显的摩尔等熵压缩率（KS,ϕ \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{ -69pt} \begin{document}$$K_{{{S,}\phi }}$$\end{document}）。限制表观摩尔等熵压缩率 (KS, ±o\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin }{-69pt} \begin{document}$$K_{{{S,}\phi , \pm }}^{{\text{o}}}$$\end{document}）。KS,ϕ,±o\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{ upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$K_{{{S,}\phi , \pm }}^{{\text{o}}}$$\end{document} 与溶剂组成的值显示烷基铵的优先溶剂化 (RNH3+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{RNH}}_ {3}^{ + }$$\end{document}) 离子在富含 AN 的区域中通过 DMA 和在富含 DMA 的区域中通过 AN。发现在所有研究温度下，烷基铵离子的溶剂化程度随着烷基链长度的减少而增加；PrNH3+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin} {-69pt} \begin{document}$${\text{PrNH}}_{3}^{ + }$$\end{document} < EtNH3+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage {wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{EtNH }}_{3}^{ + }$$\end{document} < MeNH3+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{ amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{MeNH}}_{3}^{ + }$$\end{document }. KS,φ,