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1.
短碳链醇/水混合溶剂中表面活性剂的表面性质   总被引:2,自引:0,他引:2  
李勇慧  黄建滨  王传忠  杨榕  李润锴 《化学学报》2001,59(12):2152-2157
对不同类型表面活性剂(阳离子型、阴离子型、非离子型、正负混合型)在短碳链醇/水混合溶剂中的表面物化性质进行了较为系统的研究,探讨了短碳链醇加入对体系Υcmc值和cmc值的影响。发现各类体系的Υcmc随短碳链醇加入的变化规律并非决定于表面活性剂类型而取决于该表面活性剂在水溶液中的饱和吸附量和Υcmc值的大小。  相似文献   

2.
赵剑曦 《物理化学学报》2010,26(10):2589-2596
电导率是研究水溶液中离子型表面活性剂胶束化行为的重要方法,本文总结了这个灵敏测定技术,分别着重讨论了两个重要特征参数(临界胶束浓度(cmc)和胶束的反离子解离度(α))的提取方法、电导率曲线某些特殊情况的分析以及预胶束化行为的研究,这对运用电导率技术研究当前不断增多的具有强分子间相互作用的表面活性剂(例如Geminis)体系具有参考价值.  相似文献   

3.
十四烷基芳基磺酸盐形成的分子有序组合体   总被引:1,自引:0,他引:1  
以表面张力法、碘光谱法、水增溶法和相态图法研究了自制的三种十四烷基芳基磺酸盐在不同条件下形成的分子有序组合体(胶束、反胶束和微乳液),并考察了分子结构、溶剂、无机盐和短链醇等对其的影响.结果表明:增加十四烷基芳基磺酸盐分子亲油基支化度,不利于其在水溶液或混合极性溶剂(乙二醇-水)中形成胶束而有利于其在非极性溶剂正庚烷中形成反胶束;溶剂极性的降低,促使表面活性剂溶液由胶束溶液→单体溶液→反胶束溶液转变;无机盐或短链醇的加入促进了水溶液中胶束的形成,且反离子价态数或醇烷基碳原子数越大,越有利于胶束形成;无机盐浓度的增加导致表面活性剂/正丁醇/正辛烷/NaCl/水形成的微乳液体系在一定温度下发生由WinsorI→WinsorIII→WinsorII型的转变.  相似文献   

4.
张莹  陈莉  肖进新  马季铭 《化学学报》2004,62(16):1491-1494
一般认为无机盐对等链长正负离子表面活性剂等摩尔混合体系的表面活性没有明显影响.通过测定等摩尔癸基三乙基溴化铵和癸烷磺酸钠混合体系在卤化钠(NaX,X=F-,Cl-,Br-,I-)溶液中的表面活性,发现高浓度的无机盐具有明显影响,使混合表面活性剂的临界胶束浓度(cmc)降低,水溶液的最低表面张力(γcmc)升高.无机盐的影响程度随NaX中X的离子半径增加而增大.可通过无机反离子对正负离子表面活性剂头基之间吸引作用的"屏蔽"及"盐析"作用对结果加以解释.  相似文献   

5.
DMABN在表面活性剂胶束水溶液中的荧光性质   总被引:1,自引:0,他引:1  
研究了对二甲氨基苯甲腈(DMABN)在各种胶束水溶液中的荧光光谱性质, 发现不同胶束栅栏层区域的不同性质影响了探针的分子内扭转电荷转移(TICT)特性. 对离子型胶束, 头基电场是主要影响因素, 促进了DMABN分子TICT态的形成, 反离子解离度琢越大, 胶束溶液中的Ia/Ib越强. 在非离子表面活性剂胶束中, 聚氧乙烯链环外壳包裹的大量水使其氢键影响明显, 而很短的聚氧乙烯链还可能带来端基氢的氢键作用. 从DMABN的光物理特性看, 欲将胶束作为分散载体利用其TICT态特性, 选择反离子解离度较大的阴离子胶束(例如SDS或SDSO)较好.  相似文献   

6.
董姝丽  李新  徐桂英 《化学学报》2006,64(20):2051-2056
利用动态光散射(Dynamic Light Scattering,DLS)、瞬态电双折射(Transient Electric Birefringence,TEB)和粘度测定方法研究了部分氟代阳离子表面活性剂氟代-2-羟基十一烷基二乙羟基甲基氯化铵(diethanolheptadecafluoro-2-undecanol methylammonium chloride,C8F17CH2CH(OH)CH2NCH3(C2H4OH)2Cl,DEFUMACl)水溶液的胶束化特性.结果表明DEFUMACl的临界胶束浓度cmc为3.8 mmol·L-1.稀溶液中随着DEFUMACl浓度的增加或者无机盐NaCl的加入,DEFUMACl胶束由球形向棒状转变,其转变浓度,即第二临界胶束浓度(cmcⅡ)为0.2 mol·L-1;电导测定的反离子(Cl-)结合度为0.72.利用球形和棒状胶束模型确定的DEFUMACl胶束聚集数分别为45和335.  相似文献   

7.
单一及复合表面活性剂对联苯菊酯微乳液的影响   总被引:2,自引:0,他引:2  
通过对单一及复合型表面活性剂水溶液临界胶束浓度(CMC)和表面张力(γcmc)的测定分析,研究了表面活性剂对以水为介质、环己酮为溶剂形成的联苯菊酯质量分数为2.5%微乳液相行为及稳定性的影响.结果表明,在几种单一非离子表面活性剂中,苯乙烯基苯酚聚氧乙烯聚氧丙烯醚嵌段型非离子表面活性剂EPE的γcmc最低,为28.18 mN/m;按m(EPE):m(SDBS)=2∶1形成的复合型表面活性剂水溶液的γcmc更低,为27.60 mN/m,有利于O/W型微乳液的形成,当其质量分数为10%时,配制联苯菊酯质量分数为2.5%微乳液的有效成分热贮分解率为2.35%.  相似文献   

8.
季铵盐二聚表面活性剂C12-s-C12·2Br(s=2、3、4、6)和非离子表面活性剂C12E10或C12E23在水溶液中生成混合胶团.其临界胶团总浓度cmcT值介于二元复配体系中各组分的临界胶团浓度cmc01和cmc02之间.当添加少量非离子型表面活性剂(在水溶液中的摩尔分数α2=0.1)时,混合胶团中C12E10或C12E23的摩尔分数均已超过0.35;随着溶液中非离子型表面活性剂含量的增大,混合胶团中逐渐以C12E10或C12E23成分为主.  相似文献   

9.
稳态荧光探针法测定三聚季铵盐表面活性剂的胶束聚集数   总被引:5,自引:0,他引:5  
以芘为荧光探针, 十六烷基氯化吡啶(CPC)为猝灭剂, 以芘的饱和水溶液为溶剂配制表面活性剂溶液, 根据芘的荧光强度之比I1/I3随表面活性剂水溶液浓度的变化, 测定了三聚季铵盐表面活性剂CTTTA的cmc值, 测定值与表面张力法测定的cmc值一致;当猝灭剂CPC的浓度取0.1~0.3 mmol·L-1范围时, 用稳态荧光探针法测定了CTTTA的胶束聚集数. 实验数据表明, 表面活性剂溶液浓度为6~10倍cmc时, 胶束聚集数N随表面活性剂浓度增大而线性增大, 并用外推法得到CTTTA的临界胶束聚集数.  相似文献   

10.
电导法测定临界胶束浓度及胶束电动力学模型的建立   总被引:2,自引:0,他引:2  
蔡亮 《大学化学》2003,18(1):54-56
采用电导法测定了 30℃十二烷基硫酸钠 (水溶阴离子型表面活性剂 )的临界胶束浓度 ,并由文献的cmc值估算了形成临界胶束的热效应ΔH与温度的关系。同时根据 30℃在cmc点以上的摩尔电导率λm 随浓度c变化的趋势 ,尝试建立了一个胶束电动力学的模型 ,认为在合适的浓度范围内 ,当离子吸附常数α与c成e指数关系α =eBc时 ,能很好符合λm 与c的关系  相似文献   

11.
利用手持技术改进测定乙醇分子结构实验   总被引:1,自引:0,他引:1  
利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。  相似文献   

12.
The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.  相似文献   

13.
14.
由于石化行业的生产需要,其材质的使用具有多样性和广泛性,经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识,根据光谱仪的测试能力及标样的采集,实现了一个或几个元素测量范围的扩展,并对其测量的影响因素进行了研究。  相似文献   

15.
The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.  相似文献   

16.
The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.  相似文献   

17.

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

  相似文献   

18.
实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。  相似文献   

19.
Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.  相似文献   

20.
非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。  相似文献   

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