首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 703 毫秒
1.
水/TX-100/正己醇/正辛烷反相微乳液的物化性质   总被引:4,自引:0,他引:4  
运用微量热计(Microcalorimeter),傅立叶变换红外(FT-IR),对水/TX-100/正己醇/正辛烷反相微乳液体系的形成过程及水的微结构进行了研究.微量热结果表明该反相微乳液的形成过程为一放热过程,且为两步反应.第一步为TX-100单体中的聚氧乙烯醚键与水分子形成氢键的过程,然后是“包裹”在反相胶束中的聚氧乙烯醚键与H2O分子形成氢键的过程,这两步反应之间存在时间差,焓变在该反相微乳液的形成过程中起着主要作用.含水量不同时,体系分别形成结合水、束缚水和自由水,并用FT-IR对此加以证实,FT-IR测试结果表明结合水、束缚水和自由水羟基吸收峰分别位于3400±20cm-1、3550±20cm-1、3220±20cm-1,在反相微乳液中脂肪醚位于比芳基醚大的极性区域,因而先于芳基醚与水作用形成氢键.  相似文献   

2.
微乳液结构的研究   总被引:6,自引:1,他引:6  
测定了十二烷基磺酸钠/正丁醇/20%苯乙烯/水体系的相平衡,用冷冻刻蚀、ESR、FT-IR研究了上述体系微乳液的结构,研究表明,苯乙烯含量恒定时,随着体系中水含量增加,电导确定的双连续结构的微乳液经历着从油包水到以连续再到水包油变化,FT-IR测定表明,W/O微乳兴较O/W微乳液的OH伸缩振动和弯曲振动频率有显著减小,说明W/O微乳兴中氢键缔合要比O/W强得多。ESR测定表明O/W微乳液的旋转相关  相似文献   

3.
微乳液体系中过硫酸钾氧化碘离子的动力学研究   总被引:2,自引:0,他引:2  
安学勤  王涛  沈伟国 《化学学报》2002,60(6):980-984
分别在不同盐浓度的自由水和不同液滴尺寸的微乳液中测量了过硫酸钾氧化碘 离子的化学反应速率常数,获得微乳液不核中水的活度,探讨了水的活度及体系中 离子强度与反应速率的关系,发现当表面活性剂与水的摩尔比R≤20时,水的活度 随微反应器尺寸减小而快速下降。  相似文献   

4.
本文研究了醇类(正丁醇、正戊醇、正辛醇和正癸醇)、油类(正十八烷、正十六烷、正十四烷、正十烷、正癸烷和正辛烷)、正十八烷含量以及NaCl浓度对Tween80/醇/油/水体系相图的影响。结果表明,NaCl浓度对Tween80/正辛醇/正十八烷/水体系相图的影响不明显;醇类随着炭原子数目的增加,O/W微乳液区面积增大,W/O微乳液区面积减小,微乳液区总面积增大;不同的油类形成的微乳液区面积由大到小的顺序是:正十六烷≈正十四烷>正十二烷>正癸烷>正十八烷>正辛烷;随着正十八烷含量的增加,微乳区面积减小。用2277热活性检测系统测定了石油菌B-2分别在非微乳液和助表面活性剂分别是正戊醇、正辛醇,油是正十八烷所形成的微乳液中生长的功率-时间曲线。结果表明微乳液培养基更适用于B-2利用高碳烷烃进行生长;正辛醇作助表面活性剂形成的微乳液培养基比正戊醇作助表面活性剂形成的微乳液培养更为有利;O/W型微乳液比W/O型微乳液对B-2的生长更为有利。  相似文献   

5.
微乳液体系中过硫酸钾氧化碘离子的动力学研究   总被引:1,自引:0,他引:1  
分别在不同盐浓度的自由水和不同液滴尺寸的微乳液中测量了过硫酸钾氧化碘 离子的化学反应速率常数,获得微乳液不核中水的活度,探讨了水的活度及体系中 离子强度与反应速率的关系,发现当表面活性剂与水的摩尔比R≤20时,水的活度 随微反应器尺寸减小而快速下降。  相似文献   

6.
水/TX-100/正己醇/正辛烷反相微乳液中水的微环境研究   总被引:1,自引:0,他引:1  
运用傅立叶变换红外光谱(FT-IR)对水/TritonX-100/正己醇/正辛烷反相微乳液体系中水的微结构进行了研究,结果表明,随着体系加水量的增加,水分子中O-H伸缩振动的红外光谱强度在3360cm-1附近增加,而醚上的C-O-C反对称伸缩振动峰则向低频移动,差谱处理后为负峰,对3035-3700cm-1范围内水分子的羟基伸缩振动峰进行曲线拟合后得到三个子峰,分别位于3550±20cm-1,3400±20cm-1,3220±20cm-1,对应着束缚水、结合水、自由水的微环境,并用染料探针对水的微环境加以研究。正己醇的羟基伸缩振动峰无变化说明正己醇在该反相微乳液中与水作用很弱,主要位于反相微乳液的栅状层中。并用电子显微镜对反相微乳液进行了观察。  相似文献   

7.
O/W微乳液对Zn(Ⅱ)—PAR的增敏作用   总被引:2,自引:1,他引:2  
研究了十六烷基三甲基溴化铵9CTMAB)/正戊醇/正庾烷/水组成的阳离子型O/W微乳液对以4-(2-吡啶偶氮)间苯二醇(PAR)为显色剂,光度法测定锌的增敏作用。结果,方法简便、快速,与相应的胶束体系为介质比较,提高了测定灵敏度,结果可靠。通过对显色剂在水-微乳液和在水-胶束相中分配系数的测定,初步了微乳液的增敏作用机理。  相似文献   

8.
二烷基磷(膦)酸钠盐萃取体系的相行为   总被引:4,自引:0,他引:4  
用二烷基磷(膦)酸钠盐NaA作为阴离子表面活性剂,测定了NaA-醇-油-水体系W/O型微乳液中水的增溶量,用类三元相 图单相微乳区,测定了NaDTMPP-HDTMPP-煤油-水(含Na2SO4)体系相的变化,并讨论了溶剂、醇、温度、含盐量等对相行为的影响。  相似文献   

9.
SDS/BA/H2O体系的扩散系数与结构特性   总被引:3,自引:1,他引:3  
在无探针条件下,用电化学方法测定了SDS/BA/H2O三组分体系的扩散系数和扩散活化能。结果表明,L1区域由O/W结构微乳液与油、水双连续结构微乳液两个小区域组成,并不是单一的O/W区域。在O/W区域内,微乳液以液滴状态存在,具有较好的扩莠性能和较小的扩散活化能;在BI区域,水与BA同作为连续相与被增溶相存在,缔合体系呈网络结构,扩散性能较低,扩莠活化能较大。  相似文献   

10.
CPDB/正丁醇/正辛烷/水体系溶致液晶的^2HNMR和DSC法研究   总被引:10,自引:1,他引:10  
测定了溴化十六烷基吡啶/正丁醇/正辛烷/水体系的相平衡,在液晶区域选取样品点,用^2HNMR和差示扫描量热法,并与液晶纹理相对照研究了该区域的相结构变化,结果表明,在一定温度下,随着含水量的增加,体系从单一的W/O型微乳液→微乳液和层状液晶共存→层状液晶与六角状液晶共存→层状、六角状与六角状向立方状过渡晶型的三相共存→立方状→O/W型微乳液过度,在组成固定情况下,研究了该体系液晶相结构随温度升高所  相似文献   

11.
用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.  相似文献   

12.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

13.
A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.  相似文献   

14.
A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.  相似文献   

15.
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.  相似文献   

16.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion.  相似文献   

17.
The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.  相似文献   

18.
Siqi Li  Xingpeng Chen  Jiaxi Xu 《Tetrahedron》2018,74(14):1613-1620
Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular SN2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.  相似文献   

19.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

20.
N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号