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1.
吴芯芯  赵平三 《分析化学》1996,24(2):230-233
本报道新的以三-十二烷基胺(TDDA)为载体和以对氯苯硼四-十二铵(ETH2191)为载体的pH微电极膜,与原有的TDDA膜相比较,新的TDDA膜和ETH2191膜制备更加容易,膜内阻从原有的2×10^11Ω(1μm)下降到3.5×10^10Ω(1μm),其中ETH2191膜的动力学响应pH范围为12~4.5,与原有的TDDA膜(pH范围为12~5.5)比较,拓宽了1个pH,而且ETH2191膜  相似文献   

2.
林民  赵琦 《催化学报》1999,20(1):29-34
利用^29Si和^1HNMR方法研究了TS-1分子筛合成过程中正硅酸乙酯(TEOS)的水解行为,^1HNMR结果表明,TEOS在四丙基氢氧化铵(TPAOH)溶液中的水解速度快于在四乙基氢氧化铵(TEAOH)中的水解速度,TEOS水解后的^29SiNMR谱显示,TEOS在TPAOH中水解产生的合硅酸根物种的分布与TEAOH中的类似,都存在着单体、二聚、三聚及环聚等硅酸根物种的平衡,但TEOS-TEA  相似文献   

3.
用~(31)P核磁共振波谱定性定量分析了烷基磷酸酯盐(I)和烷基聚氧乙烯醚磷酸酯盐(Ⅱ)中各含磷组分及其含量。研究了溶液pH值、氯化钠含量、样品浓度等对各组分~(31)P化学位移的影响。探讨了影响定量准确度的因素;找出了最佳分析条件。  相似文献   

4.
丙烯酰胺和表面活性大单体共聚物的合成及其性能研究   总被引:8,自引:0,他引:8  
许国强  黄雪红 《合成化学》1999,7(2):182-186
首先合成表面活性大分子单体丙烯酸聚氧乙烯(23)-十二烷基酯(AA-POELE),再通过与丙烯酰胺共聚合的方法得到在水溶性聚合物聚丙烯酰胺分子结构中引入疏水基团的共聚物改性PAM。因AA-OPELE单体具有表面活性,所以共聚合时无需添加乳化剂。当改性PAM中疏水基团含量为1.10mol%时,其水溶液表现出独特的流变性和增稠性,着重讨论了改性PAM作为乳胶增稠剂的性能。  相似文献   

5.
磷酸酯类阴离子表面活性剂的^31P—NMR波谱分析   总被引:2,自引:0,他引:2  
用^31P核磁共振波谱定性定量分析了烷基磷酸酯盐(1)和烷基聚氧乙烯醚磷酸酯盐(2)中各含磷组分及其含量。研究了溶液PH值、氯化钠含量、样品深度等对各组分^31P化学位移的影响。探讨了影响定量准确度的因素;找出了最佳分析条件。  相似文献   

6.
研究了1-苯基3-甲基-4-(呋喃甲酰基)-5-吡唑酮(HA)萃取镱及其分别与丁基辛基亚砜(BOSO)、戊基已基亚砜(PHSO)、乙基十二烷基亚砜(EDSO)、二苯亚砜(DPSO)和TBP协同萃取镱的行为。协萃配合物的组成为YbA_3·B,HA的萃取平衡常数为—5.64±0.04,中性萃取剂的协萃能力比单独萃取时高3~4个数量级,协萃效果明显。  相似文献   

7.
通过 Fourier变换红外光谱(FT-IR),扩展X射线吸收精细结构(EXAFS),等离 子发射(ICP)和同位素示踪等方法对氯化甲基三烷基铵(N263)-磷酸三丁酯(TBP)-正十二 烷和N263-异辛醇-正十二烷从KAu(CN)_2水溶液中萃取金的机理进行了深入的研究.应 用高分辨红外光谱证实负载有机相中CN伸缩振动吸收随萃金体系中助萃剂的不同而不 同,并将负载有机相中Au(CN)_2~-与助萃剂的相互作用归因于氢键机制,认为萃金体系中 的萃合物模型为基于氢键的超分子体系  相似文献   

8.
利用多核Nd-Al双金属配合物可单独引发双烯烃聚合的特点,考察了烷基铝种类对丁二烯加聚过程的影响,并与一般混合稀土催化体系进行了比较.烷基铝对活性体催化活性的影响与其用量有关,低n(Al)/n(Nd)值时,活性次序为:AlMe3,AlEt3,HAlBui2>Al(C8H17)3>AlBui3;高n(Al)/n(Nd)值时,活性次序相反:AlMe3,AlEt3,HAlBui2<Al(C8H17)3<AlBui3.烷基铝链转移作用强弱次序为:HAlBui2≥AlEt3>AlBui3>AlMe3>Al(C8H17)3.根据聚丁二烯微观结构与其分子量的关系,可将烷基铝对聚丁二烯顺式含量的影响分为3类:(1)AlEt3和Al(C8H17)3;(2)HAl-Bui2和AlBui3;(3)AlMe3.所得结果有助于对稀土催化定向聚合过程的深入了解.  相似文献   

9.
采用十二烷基二甲基苄基氯化铵(1227)乳化剂,对丙烯酸丁酯(BA)-苯乙烯(St)进行乳液共聚,研究了影响聚合速度的各种因素,得出了聚合速率方程和表观活化能.  相似文献   

10.
聚N-烷基丙烯酰胺类凝胶及其温敏特性   总被引:11,自引:3,他引:11  
 研制成功5种聚N-烷基丙烯酰胺类温敏凝胶:聚N-异丙基丙烯酰胺(PNIPA),聚N-异丙基丙烯酰胺+甲基丙烯酰胺(PNIPA/MAA),聚N,N-二乙基丙烯酰胺(PNDEA),聚N-正丙基丙烯酰胺(PNNPA),聚N,N-二乙基丙烯酰胺+N-叔丁基丙烯酰胺(PNDEA/NTBA),并系统研究了这些凝胶的温敏相交特性.以聚N-异丙基丙烯酰胺(PNIPA)凝胶相交特性为基础的凝胶萃取过程对牛血清白蛋白和兰葡聚糖溶液的浓缩实验表明,凝胶萃取对于浓缩和制备贵重生化制品是很有效的.  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.
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   

13.
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   

14.
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   

15.
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   

16.
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   

17.
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.  相似文献   

18.
In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.  相似文献   

19.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.  相似文献   

20.
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