Thermodynamic Study on Phase Transition in Adsorbed Film of Fluoroalkanol at the Hexane/Water Interface. 2. Pressure Effect on the Adsorption of 1,1,2,2-Tetrahydrohenicosafluorododecanol
{"title":"Thermodynamic Study on Phase Transition in Adsorbed Film of Fluoroalkanol at the Hexane/Water Interface. 2. Pressure Effect on the Adsorption of 1,1,2,2-Tetrahydrohenicosafluorododecanol","authors":"Takanori Takiue, Atsuro Yanata, Norihiro Ikeda, Yoshiteru Hayami, Kinsi Motomura, Makoto Aratono","doi":"10.1021/jp9623554","DOIUrl":null,"url":null,"abstract":"<p >The adsorption behavior of 1,1,2,2-tetrahydrohenicosafluorododecanol, CF<sub>3</sub>(CF<sub>2</sub>)<sub>9</sub>(CH<sub>2</sub>)<sub>2</sub>OH (FC<sub>12</sub>OH), at the hexane/water interface was investigated in both the absence and presence of the deposit by measuring the interfacial tension γ of its hexane solution against water as a function of pressure <i>p</i> and molality <i>m</i><sub>1</sub> at 298.15 K. It was concluded that a breakpoint on the γ vs <i>p</i> and γ vs <i>m</i><sub>1</sub> curves in a very low concentration region shows a first-order phase transition from the gaseous to the condensed state in the adsorbed film. It was found that the volume change of adsorption per mole of FC<sub>12</sub>OH is larger than that of 1,1,2,2-tetrahydroheptadecafluorodecanol, CF<sub>3</sub>(CF<sub>2</sub>)<sub>7</sub>(CH<sub>2</sub>)<sub>2</sub>OH (FC<sub>10</sub>OH). Then it was suggested that the increase in the partial molar volume of alcohol with increasing fluorocarbon chain length is larger in the solution than in the interface because of the weak mutual interaction of the fluorocarbon chain with hexane molecules. Furthermore, another breakpoint due to the solubility of FC<sub>12</sub>OH in hexane was observed on the γ vs <i>p</i> and γ vs <i>m</i><sub>1</sub> curves in a high concentration and pressure region. A small value of partial molar volume change accompanied by the adsorption from the solid substantiates our view that the condensed state of the adsorbed film resembles the solid state. </p>","PeriodicalId":58,"journal":{"name":"The Journal of Physical Chemistry ","volume":null,"pages":null},"PeriodicalIF":2.7810,"publicationDate":"1996-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1021/jp9623554","citationCount":"22","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"The Journal of Physical Chemistry ","FirstCategoryId":"1","ListUrlMain":"https://pubs.acs.org/doi/10.1021/jp9623554","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 22
Abstract
The adsorption behavior of 1,1,2,2-tetrahydrohenicosafluorododecanol, CF3(CF2)9(CH2)2OH (FC12OH), at the hexane/water interface was investigated in both the absence and presence of the deposit by measuring the interfacial tension γ of its hexane solution against water as a function of pressure p and molality m1 at 298.15 K. It was concluded that a breakpoint on the γ vs p and γ vs m1 curves in a very low concentration region shows a first-order phase transition from the gaseous to the condensed state in the adsorbed film. It was found that the volume change of adsorption per mole of FC12OH is larger than that of 1,1,2,2-tetrahydroheptadecafluorodecanol, CF3(CF2)7(CH2)2OH (FC10OH). Then it was suggested that the increase in the partial molar volume of alcohol with increasing fluorocarbon chain length is larger in the solution than in the interface because of the weak mutual interaction of the fluorocarbon chain with hexane molecules. Furthermore, another breakpoint due to the solubility of FC12OH in hexane was observed on the γ vs p and γ vs m1 curves in a high concentration and pressure region. A small value of partial molar volume change accompanied by the adsorption from the solid substantiates our view that the condensed state of the adsorbed film resembles the solid state.
在298.15 K下,通过测量其己烷溶液对水的界面张力γ随压力p和质量摩尔浓度m1的函数,研究了1,1,2,2-四氢苯基氟十二醇CF3(CF2)9(CH2)2OH (FC12OH)在己烷/水界面上的吸附行为。结果表明,在极低浓度区域的γ vs p和γ vs m1曲线上的断点显示了吸附膜从气态到凝聚态的一级相变。结果表明,每摩尔FC12OH的吸附体积变化大于1,1,2,2-四氢十六氟癸醇CF3(CF2)7(CH2)2OH (FC10OH)的吸附体积变化。结果表明,由于氟碳链与己烷分子的相互作用较弱,溶液中醇的偏摩尔体积随氟碳链长度的增加而大于界面中醇的偏摩尔体积。此外,在高浓度和高压区,在γ vs p和γ vs m1曲线上观察到由于FC12OH在己烷中的溶解度而产生的另一个断点。随着固体的吸附,部分摩尔体积变化的小值证实了我们的观点,即吸附膜的凝聚态类似于固体状态。