本文選題：二氧化碳-甲醇混合物 + 偶極-偶極作用機(jī)理��； 參考：《物理化學(xué)學(xué)報(bào)》2016年11期

【摘要】：用核磁共振氫譜測(cè)量了不同溫度(293.15和308.15 K)及壓力高達(dá)25 MPa下二氧化碳-甲醇混合氣相(超臨界)及液相區(qū)(亞臨界)中甲醇(羥基及甲基)的縱向弛豫時(shí)間T1,exp。本工作的目的是考察近臨界區(qū)二氧化碳-甲醇混合物的壓力、溫度及組成對(duì)甲醇弛豫速率的影響,揭示混合物不同相區(qū)(氣相及液相區(qū))中自旋-晶格弛豫(SLR)過(guò)程的機(jī)理。此外,還對(duì)比研究了等溫條件下超臨界和亞臨界混合氣相及液相區(qū)中甲醇的SLR速率1/T1,exp隨混合物密度的變化規(guī)律。研究發(fā)現(xiàn),在本工作所涉及的溫度及壓力區(qū)間,對(duì)于純甲醇或液相區(qū)其SLR過(guò)程是以偶極-偶極(DD)作用機(jī)理為主導(dǎo),而在氣相區(qū)SLR過(guò)程則是以自旋-轉(zhuǎn)動(dòng)(SR)作用機(jī)理占優(yōu)勢(shì),也即,超臨界和亞臨界二氧化碳-甲醇混合物的SLR過(guò)程在不同相區(qū)有不同的作用機(jī)理控制。由于甲醇的SLR弛豫速率1/T1,exp是由甲醇分子間及分子內(nèi)的DD作用和SR作用三部分共同決定的,所以研究超臨界和亞臨界二氧化碳-甲醇混合物的SLR弛豫速率隨壓力、濃度及溫度的變化規(guī)律有助于提供更多該混合物不同相態(tài)區(qū)分子間相互作用的動(dòng)態(tài)學(xué)信息。
[Abstract]:The longitudinal relaxation time T _ (1) expan of methanol (hydroxyl and methyl) in the liquid phase and in the liquid phase (supercritical) was measured by nuclear magnetic resonance (NMR) at different temperatures (293.15 and 308.15 K) and pressure up to 25 MPa. The purpose of this work is to investigate the effects of pressure, temperature and composition on the relaxation rate of methanol in the near critical region, and to reveal the mechanism of spin lattice relaxation (SLR) process in different phase regions (gas and liquid phase) of the mixture. In addition, the SLR rate of methanol in the supercritical and subcritical gas mixtures and in the liquid phase region under isothermal conditions is compared and studied with respect to the density of the mixture. It is found that in the range of temperature and pressure involved in this work, the SLR process is dominated by dipole-dipole interaction mechanism in the pure methanol or liquid phase region, while in the gas-phase region the SLR process is dominated by the spin-rotation mechanism. In other words, the SLR process of supercritical and subcritical CO2 / methanol mixtures is controlled by different mechanisms in different phase regions. Since the SLR relaxation rate of methanol is determined by the interaction of DD and SR between molecules and molecules of methanol, the SLR relaxation rate of supercritical and subcritical CO _ 2-methanol mixtures is studied with pressure. The variation of concentration and temperature is helpful to provide more dynamic information on the interaction between molecules in different phase regions of the mixture.
【作者單位】： 鄭州大學(xué)化學(xué)與分子工程學(xué)院;
【基金】：supported by the National Natural Science Foundation of China(21543009,21073167,J1210060) Innovative Research Grant for Undergraduate Students of National/Zhengzhou University,China(201410459047,201510459046,2016xjxm259)~~
【分類號(hào)】：O623.411;O642.5

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