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1.
聚乙二醇对振荡反应的影响   总被引:11,自引:1,他引:11  
前文[1]曾指出,生物体系的化学振荡反应实际上是产生于水溶胶之中(包括高分子溶液及表面活性剂溶液).作为反应介质,水溶胶对生物体系的周期现象有着不可忽略的重要作用.因此,要模拟生物体系的化学振荡就不能不考虑溶胶对振荡反应的影响.前文[2,3]报道了表面活性剂TritonX-100(简称TX-100),TritonX-305等对振荡反应的影响.为了解聚乙二醇类表面活性剂中EO链的作用及高分子溶液对振荡反应的特征影响,我们选用高分子聚乙二醇(PEG)作为添加剂,考虑由于它的加入而引起振荡反应的变化.为了减少PEG中自由羟基的还原…  相似文献   

2.
表面活性剂不仅对均相的非线性化学反应动力学研究有重要作用”-‘],而且表面活性剂穿越油水界面扩散时形成的自发液膜振荡过程亦可作为一个简单模型,用以说明多相反应与扩散偶合所产生的复杂周期现象,特别是说明生物系统生理现象中的振荡与混饨.这些早在贺占博的博士论文l’]就已提出,但至今此方面的研究仍进展甚微,而其意义却非常重大,迫切需要进一步研究.关于液膜振荡的本质,目前有两种说法.一种是界面流体力学的Marangoni效应,另一种为化学本质的胶束一单分子膜一反胶束的表面活性剂聚集状态的周期变化l’‘.我们的实验…  相似文献   

3.
皂类液膜振荡器   总被引:2,自引:0,他引:2  
实验发现了一类新型液膜振荡器,在油水两相之间进行成皂反应的过程中,界面附近出现了长时间规则的大幅度pH振荡,将W/O两相体系换成W1/O/W2三相体系,振幅从0.50 pH明显提高到2.88 pH.其中水相组成为CTAB溶液及NaOH溶液,油相组成为油酸的煤油溶液.同时,此类液膜振荡体系中亦存在明显的电势振荡和电导率振荡.为深入了解机理,进行了浓度影响测定,电极位置和种类的变化以及辅助实验等,提出了普遍化的机理,并进行了实验振荡曲线的拟合对比.这个机理指出,在膜反应批量进行的条件下,当反应速率与扩散成比例时,便会产生规则的周期现象.在一价皂液膜振荡器的基础上,通过替换或添加各种金属盐,形成了各类高价皂液膜振荡器,测定了反应过程中pH、电势及电导率的变化.经过同类化学振荡器的比较研究,结合金属离子与酸根之间的络合作用,得出了其中的一些规律.  相似文献   

4.
乙酰乙酸乙酯-BR化学振荡反应的研究   总被引:2,自引:0,他引:2  
本文首次报道了乙酰乙酸乙酯-IO-3-H2O2-Mn2+-H2SO4体系的化学振荡反应。研究了各种因素对振荡反应的影响,测定了最佳反应条件及振荡反应的浓度范围。研究了温度变化对振荡反应的影响,并计算了振荡反应的表观活化能,对振荡反应产物进行了分析,并测定了体系主要反应的计量关系,采用UV法对金属离子的作用和催化机理作了研究,探索了BR反应中I2的产生机理及消耗机理,对体系中有关反应物的作用作了说明。在FKN机理的基础上,对BR反应的自催化反应步骤和控制机理进行了初步的探索,并对有关实验现象作了说明。  相似文献   

5.
磁化后掺水乳化重油分散度的实验研究   总被引:2,自引:2,他引:0  
乳化重油的分散相(水)微粒大小对重油掺水乳化燃烧技术的应用效果有很大影响,本人在过去实验的基础上,用光学反射显微镜法对磁场作用下掺水乳化重油中分散相(水)的分散度进行了测定,研究了乳化重油的分散度与磁场强度、温度以及流速之间的关系,实验结果表明:磁化后有利于乳化重油的微细化,且效果比较显著;温度的升高有利于分散相(水)的微细化,兼顾能耗和燃油的发泡、沸腾现象,以及磁化后温度的升高对分散度的影响减少,有一个合理的温度范围;磁化后分散度与流速的关系呈峰值关系,本实验中流速较佳值为8m/s;磁场强度的增大也有利于微细化,磁场强度太高或太低均不会取得太好的处理效果,在1000GS-1400GS范围内为宜。  相似文献   

6.
《有机化学》2008,28(7)
两亲性离子或中性分子受疏溶剂作用驱动在水相中聚集形成胶束、膜及囊泡等结构是非常普遍的自组装现象,也是生命现象产生的基础.但非两亲性分子在极性溶剂中形成囊泡结构,文献报道极少.中国科学院上海有机化学研究所黎占亭等以近年来发展的酰肼折叠体为刚性骨架,在其外侧引入带有长脂肪链的酰胺侧链.  相似文献   

7.
本文首次报道了乙酰乙酸乙酯-IO3^--H2O2-Mn^2+-H2SO4体系的化学振荡反应。研究了各种因素对振荡反应的影响,测定了最佳反应条件及振荡反应的浓度范围。研究了温度变化对振荡反应的影响,并计算了振荡反应的表观活化能,对振荡反应产物进行了分析,并测定了体系主要反应的计量关系,采用UV法对金属离子的作用和催化机理作了研究,探讨了BR反应中I2的产生机理及消耗机理,对体系中有关反应物的作用作了  相似文献   

8.
DSB显著提高羧酸盐驱油体系抗钙镁离子能力的研究   总被引:2,自引:0,他引:2  
测定了工业品级的天然混合长链烷基羧酸盐(SDC)以及与3-(N,N-二甲基十二烷基胺)-2-羟基-丙磺酸(DSB)复配驱油体系的界面张力(ITFmin), 分别得出其抗钙镁离子的能力为400和5000 mg/L. 选择试剂级十二烷基羧酸钠与DSB复配, 测定了不同配比溶液的表面张力值和临界胶束浓度cmc, 结合长链烷基脂肪酸与钙离子的溶度积Ksp, 分析了对不溶性长链烷基羧酸盐形成的影响. 根据现场驱油体系配方, 计算了两者在溶液中的摩尔配比为4:1时的十二烷基羧酸盐在胶束中的摩尔分数xm1为0.51, 相互作用参数βm值为-3.11, 反映了两者有较强的相互作用. 采用量子化学方法, 对由1个十二烷基羧酸分子、1个DSB分子及1个二价钙离子组成的模型复合物进行了能量计算和电荷分布计算, 得出在长链烷基羧酸盐和DSB两者混合胶束的界面层中存在负电荷空穴, 提出二价金属离子被络合的模型, 合理地解释了实验事实.  相似文献   

9.
微环境对长链香豆素酯光化学和光物理过程的影响   总被引:3,自引:1,他引:2  
疏水作用在胶束、膜的形成以及生命过程中起着重要的作用.疏水作用可促使长链分子相互簇集,造成局部浓度效应和分子的有序排列[1~3],疏水作用对光化学和光物理过程的影响是一种微环境效应.本文合成了十六酸和十八酸-4-甲基-7-羟基香豆素酯,研究了它们在有...  相似文献   

10.
几种电子给体(四硫代富瓦烯,TTF)、电子受体(长链四氰基对二次甲基苯醌;C18 TCNQ)及它们相应的 1:1摩尔比复合物的气-液界面分子行为表明:不带长链的 TTC1- TTF、BEDT-TTF的成膜性在其与C18TCNQ形成复合物之后均得到显著改善。C16TTF、C18 TCNQ及两者不同结构LB膜组装体的紫外可见光谱研究发现:C18TCNQ在其单独的Y-型 膜中摩尔吸光系数是7.5×103,而在交替组装体中其摩尔吸光系数是1.3×103,给受体之间 的相互作用导致跃迁偶极矩减小,从而引起吸光系数减小4倍多。  相似文献   

11.
Zhan‐Bo He  Gang Qi 《中国化学》2001,19(7):710-713
A new type of oscillating reaction was found from the systematic design of the chemical oscillator in water in oil (W/O) emulsions. It is an acidity hydrolysis reaction of long chain triglyceride in W/O emulsion at 25.0 ± 0.1°C in a bath stirring reactor. During the process of reaction, there were periodic and semi‐periodic changes lasting more than 10 hours both in electrolytic conductivity and electric potential. Microscope also revealed that the emulsion structure changed regularly and quickly. Because of the large difference in the solubility of the hydrolyzed products, it could be thought, that the different redistribution in the two phases of water and oil induces the regular changes. Marangoni effect of interface membrane made oscillation to form. The oscillating reaction can be used to explain the periodic change in the living system produced from coupling between reaction and diffusion.  相似文献   

12.
用乳状液膜体系对钼进行富集。该体系包括载体 ( 5,8-二乙基 - 7-羟基十二烷 - 6-单肟 ,简称LIX63)、表面活性剂 (N1 1 3C)、溶剂(煤油 )以及内相 ( 0 .1 5mol/LNaOH溶液 )。研究了乳状液膜的稳定性、温度、钼的浓度、外相的HNO3溶液浓度及乳水比等因素对分离富集钼的影响。实验表明 ,在适宜的条件下 ,钼的迁移率可达 99.5%~1 0 0 .2 %。该法已应用于富集、测定纯钨和钢铁中的痕量钼 ,结果相当满意  相似文献   

13.
Water-in-diesel (W/D) emulsion fuels were prepared through an ultrasonic processor by using high energy emulsification method. Accordingly, the physical and chemical properties were analyzed. A decrease in viscosity was found in the emulsion fuel in contrast to the neat diesel which signifies the enhanced fluidity of the fuel. The emulsion fuel was then used to carry combustion tests in an internal combustion engine. A decrease in exhaust temperature was observed when a high surfactant to water ratio was used, which lead to minimal heat loss. As water is emulsified with diesel, effectiveness of combustion is improved rather than neat diesel fuel. It was also explored that the addition of water-in-diesel is influential in terms of reduction in exhaust gas emission such as carbon dioxide, carbon monoxide, ammonia from the internal combustion engine. Therefore, this type of emulsion fuel would be a useful contribution in the fuel economy, but also in making it environmentally friendly since diesel fuel is now considered one of the leading fuels causing ecological contamination.  相似文献   

14.
乳液引起的Daniell电池中的电化学振荡   总被引:1,自引:0,他引:1  
由油酸的煤油溶液与NaOH和CTAB两水溶液混合制成O/W型乳液.实验发现,此乳液的加入可使丹尼尔电池产生电池反应与电极反应的明显振荡现象.自发过程结束后,通以2 V, 50 Hz或100 Hz交流电4 h,则此电池反应可形成可逆振荡.由表面活性剂对电极表面的吸附和乳液结构变化解释了振荡机理.乳液混合能参与了此电化学反应.  相似文献   

15.
A new stable green emulsion liquid membrane (GELM) was formulated by selecting the environmentally benign vegetable oils. The rice bran oil (RBO) based GELM has shown better stability in comparison to that obtained from other oils. GELM was prepared using 10?mL RBO, 0.25 [M] NaOH concentration, 2 (v/v, %) surfactant concentration, 0.4 (v/v) phase ratio, 2000?rpm emulsification speed, and 20?min emulsification time. Under these optimum conditions, GELM has been found to be stable for 120?±?2?min (no significant phase change) and has shown complete phase separation after 4 hours. Therefore, RBO as a green solvent has high potential to be applied in several ELM process applications.  相似文献   

16.
The stability of water-in-crude oil emulsions is frequently attributed to a rigid asphaltene film at the water/oil interface. The rheological properties of these films and their relationship to emulsion stability are ill defined. In this study, the interfacial tension, elastic modulus, and viscous modulus were measured using a drop shape analyzer for model oils consisting of asphaltenes dissolved in toluene for concentrations varying from 0.002 to 20 kg/m(3). The effects of oscillation frequency, asphaltene concentration, and interface aging time were examined. The films exhibited viscoelastic behavior. The total modulus increased as the interface aged at all asphaltene concentrations. An attempt was made to model the rheology for the full range of asphaltene concentration. The instantaneous elasticity was modeled with a surface equation of state (SEOS), and the elastic and viscous moduli, with the Lucassen-van den Tempel (LVDT) model. It was found that only the early-time data could be modeled using the SEOS-LVDT approach; that is, the instantaneous, elastic, and viscous moduli of interfaces aged for at most 10 minutes. At longer interface aging times, the SEOS-LVDT approach was invalid, likely because of irreversible adsorption of asphaltenes on the interface and the formation of a network structure.  相似文献   

17.
A rhythmic, sustained, stable potential oscillation was reproducibly observed for a lipid membrane supported by a micropore of a thin membrane tip micropipet. Amplitude and period of the oscillation voltage were controlled by changing the pore diameter. The smaller the hole diameter, the smaller the amplitude and the period became. We call this relationship “size effect.” We observed with an optical microscope dynamic behavior of lipids across the oil/water interface, which are formed at a micropore of 2 μm in diameter during self-excited potential oscillation. Periodical movement of a dome-shaped body on the interface is observed, and its expansion and shrinkage are quite synchronous with the potential oscillation. We also applied this self-excited potential oscillation device as a chemical sensor, and reported the effect of chemical substance added into the water phase as a model for the biological chemoreceptive membrane. The experimental results of microscopic observation show that the sensing system using the micropore can distinguish different chemical substances as well as their concentrations, suggesting its application as a chemical sensor.  相似文献   

18.
提出用TTA-TBPO为协同流动载体的乳状液膜分离它集抗(Ⅲ)的方法。其最佳液膜体系的组成为4%Span80.5%TTA、3%TBPO、4%液体石蜡、84%煤油和内相水溶液(4mol/L),最优实验条件,提取钪(Ⅲ)的外相试液为pH=1.3~2.3,Roi(油内比)为1:1,Rew(乳水比)为20:100。本法用于分离富集稀土元素中的微量钪(Ⅲ),其回收率可达99.1%以上,相对标准偏差为3.5%以下,结果十分满意。  相似文献   

19.
皂化P204/煤油微乳体系分离L-苯丙氨酸的研究   总被引:5,自引:0,他引:5  
研究了P204-煤油-NaOH组成的微乳液膜配方及其稳定性。通过该液膜体系对L-苯丙氨酸水溶液进行提取实验,考察了P204的浓度、乳水比、外水相pH值、膜相重复使用次数、分离时间等对提取效率的影响。实验结果表明,微乳液膜不仅稳定性好,无明显溶胀和泄漏,分离速度快,而且分离效果好,可自动破乳,油相可重复多次使用,对L-苯丙氨酸的一次性提取率达88.25%。  相似文献   

20.
液膜分离富集金与测定微量金   总被引:2,自引:0,他引:2  
提出采用乳状液膜体系分离、富集金。该体系包括协同流动载体(TBP和PMBP),表面活性剂(SPAN80),膜的增强剂(液体石蜡),膜溶剂(煤油)和内相(1%质量分数的NaOH水溶液)。实验结果表明,金的迁移率达90.5%以上。此条件下,许多共存金属高于如∑RE3+、Ag2+、Pd2+、Pt4+、Rh3+、Cu2+、Fe3+、Al3+、Pb2+、Zn2+、Mo6+、W6+、Mn2+、Sn4+、Te4+、Se4+、Ca2+和Mg2+等不被迁移,只有金能与这些金属离子得到满意的分离。该法已应用于测定提金溶液和氰化物没出贵金属溶液中的微量金,相对标准偏差为1.3%-3.9%。  相似文献   

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