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1.
在CCSD(T)/6-311G(d,p)//B3LYP/6-311G(d,p)+ZPE水平上对反应·CHCHCH3+NO进行了计算, 并建立了其单重态的反应势能面. 在该反应中, 分别找到生成P1(CH3CHO+HCN), P2(CH3CHO+HNC), P3(CH3CN+HCHO), P4(CH3CCH+HNO)的4条产物通道, 其中·CHCHCH3和NO中的氮原子直接连接形成m1(trans-CH3CHCHNO), m1经过顺反异构形成m2(cis-CH3CHCHNO), m2再经过CCNO四元环合, 然后发生环解离, 最后生成产物P1(CH3CHO+HCN)是最可行的产物通道, 其余三条通道为次要产物通道. 该体系中生成P1的反应路径与同类体系·C2H3+NO的主要反应路径相类似, 两者的差别是前者为动力学可行的反应, 而后者为动力学不可行反应, 这使得·CHCHCH3+NO反应比·C2H3+NO反应更具有实际意义.  相似文献   

2.
以隐性亮绿 (RBG)为氢供体底物 ,研究了辣根过氧化物酶 -H2 O2 -RBG显色反应体系的酶催化特性。在 p H 5.0~ 6.0的条件下反应形成的酶催化产物亮绿 (BG)于 63 0 .6nm处有最大吸收 ,该显色反应测定 H2 O2 的表观摩尔吸光系数为 5.64×1 0 4 L·mol- 1·cm- 1,线性范围为 3 .55× 1 0 - 8~ 6.0× 1 0 - 6 mol/ L,检出限为 3 .55×1 0 - 8mol/ L。方法用于雨水中痕量 H2 O2 的测定 ,结果满意  相似文献   

3.
单重态二溴卡宾和甲醛环加成反应的量化研究   总被引:4,自引:0,他引:4  
采用量子化学密度泛函理论,研究了单重态二溴卡宾和甲醛环加成反应的机理.在B3LYP/6-31G*基组水平上,优化得到了反应途径上反应物、过渡态、中间体和产物的几何构型;计算并考察了四种可能反应途径势能面上各驻点的构型参数、振动频率和能量;通过振动分析对过渡态和中间体构型进行了确认.计算结果表明,二溴卡宾和甲醛反应有四条反应通道,其中c反应通道(即0°-0°型)控制步骤的活化能仅为13.7 kJ·mol-1,反应容易进行.  相似文献   

4.
利用瞬态吸收光谱技术进行了有氧、无氧条件下苯与亚硝酸水溶液复相体系的交叉反应机理研究 ,初步考察了这些瞬态物种的生长与衰减等行为 ;并对其光解产物进行了GC/MS分析 .研究表明 ,HNO2 在 3 5 5nm紫外光的照射下可产生·OH和NO+ ,·OH自由基和苯反应生成C6H6 OHadduct ,反应速率常数为 8 9× 10 9L·mol-1·s-1,在有氧条件下C6H6 OHadduct进一步氧化为C6H6 OHO2 ,反应速率常数 3 3× 10 8L·mol-1·s-1;NO+ 自由基和苯作用形成C6H6 NO+ πcomplex ,然后进一步分解  相似文献   

5.
氨基酸与乙酰丙酮和甲醛反应得到的产物能发出荧光,据此建立了同步荧光光谱法测定滁菊中氨基酸总量的方法。以苯丙氨酸作为测定滁菊中氨基酸总量的目标物。优化的试验条件如下:1苯丙氨酸、谷氨酸的波长差为55nm;2甘氨酸和混合氨基酸的波长差为60nm;3反应体系的pH为6.0;4反应温度为100℃;5反应时间为60min;6 4%甲醛溶液用量为1.5mL;7 2%乙酰丙酮溶液用量为1.25mL。苯丙氨酸的质量浓度在5.00~50.0mg·L-1范围内与其荧光强度呈线性关系,方法的检出限(3s/k)在0.30~0.87mg·L-1之间。对苯丙氨酸样品连续测定10次,测定值的相对标准偏差为1.2%。用标准加入法做方法的回收试验,计算得回收率在64.7%~103%之间。  相似文献   

6.
甲醛-乳酸-丙酮-Mn2+-BrO-3-H2SO4振荡反应动力学分析研究   总被引:2,自引:0,他引:2  
甲醛对乳酸 丙酮 Mn2+ BrO-3 H2SO4化学振荡反应的诱导期tin有显著的影响,甲醛浓度的对数ln[HCHO]与诱导期倒数的对数ln(1/tin)有良好的线性关系,线性范围为5.0×10-8~1.0×10-3mol·L-1。在此浓度范围内,该体系是一重现性好,灵敏度高,操作简单的甲醛动力学分析测试体系。获得的诱导期、周期的表观活化参数Ein、Ep分别为64.7kJ·mol-1、65.0kJ·mol-1。  相似文献   

7.
对氯柱硼镁石(2MgO·2B_2O_3·MgCl_2·14H_2O)在30℃时水中溶解和相转化过程的研究结果表明,该复盐在水中呈现不同步溶解.首先溶脱掉MgCl_2·6H_2O,生成中间产物MgO·B_2O_3·4H_2O.随后发生转化,最终结晶产物是多水硼镁石.在给出溶解转化结晶动力学方程的基础上提出溶解转化结晶反应机制.  相似文献   

8.
氨基酸-乙酰丙酮分光光度法测定水样中甲醛   总被引:1,自引:0,他引:1  
试验了用氨基酸代替氨水或乙酸铵作为胺源的条件下,乙酰丙酮与甲醛反应生成有色化合物的适宜条件并提出了氨基酸-乙酰丙酮分光光度法测定水中甲醛的方法。优化的试验条件如下:①0.12mol·L-1甘氨酸衍生剂用量为2mL;②反应温度为50℃;③反应时间为15min;④反应体系的pH为4.7。甲醛的质量浓度在0.2~1.0mg·L-1范围内与吸光度呈线性关系,检出限为5μg·L-1。加标回收率均不小于98.0%,测定值的相对标准偏差(n=6)均不大于4%。方法应用于地表水样中甲醛的测定,测定值与国标法测定结果相符。  相似文献   

9.
在氨水-NH4Cl介质(pH 9.0)和沸水浴加热下,铜离子对氨苄青霉素的降解反应具有催化作用,其降解产物可产生荧光。据此建立了测定氨苄青霉素的方法。氨苄青霉素的浓度在1.5×10-7~3.0×10-6mol·L-1范围内与荧光强度呈线性关系,检出限为4.0×10-8mol·L-1。可用于氨苄青霉素胶囊的分析及尿液中氨苄青霉素的测定,平均回收率为95.3%~101.4%。研究表明,反应的活化能为34.88 kJ·mol-1,100℃速率常数为4.68 h-1。  相似文献   

10.
分光光度法测定人尿液中的酪氨酸   总被引:8,自引:0,他引:8  
研究了硝酸介质酪氨酸与α-显色剂的显色反应体系。显色产物在 52 0nm处有最大吸收 ,表观摩尔吸光系数为 6.1 9× 1 0 3L· mol- 1· cm- 1。酪氨酸含量在 0 .0 2~ 0 .1 6μmol/m L 范围内符合比尔定律 ,该法可用于人尿中酪氨酸的测定。  相似文献   

11.
HEPT类化合物的QSAR研究   总被引:3,自引:0,他引:3  
章文军  许禄 《应用化学》2001,18(9):717-0
为定量结构/活性相关性研究提取了量子化学参数,拓扑指数Am,分子连接性指数^mxt及疏水性常数,同时应用正交变换和最佳变量子集算法(Leaps-and-Bonds)进行了变量压缩和选择,进而实施了多元回归分析,并由此结果进行了HEPT类化合物(1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)-thymine derivatives)的结构/活性关系的理论解释,进行了人工神经网络法对于该类化合物的活性预测,其结构明显好于多元回归法。  相似文献   

12.
Similarity of the extrusion curves of non-wetting liquid in a nanoporous medium with different initial fill volume fractions is observed experimentally. The similarity can be explained by the scaling of the interface energy and the self-similarity of the infinite percolation cluster of fluid-filled pores. Understanding the physical processes leading to the observed phenomena is a foundation for the development of high-performance devices for damping and energy storage on the basis of such heterogeneous systems.  相似文献   

13.
The content of the fine and ultrafine particles in the raw material results in difficulty of the separation, the loss of the valuable components and ecological contamination. Secondary using of the fine particles is impossible without their granulation. This problem has been solved by the agglomeration-in-liquid method.An agglomeration-in-liquid method is a process to produce agglomerates in a liquid phase from solid particles suspended in the liquid. The surface of solid particles and the binding liquid must be of identical polarity, but the continuous phase must be of the opposite polarity. The water solutions of the surfactant are the binding liquids or the organic liquids.  相似文献   

14.
The synthesis and liquid crystalline behaviour of the first and second generations of a dendrimeric structure based on poly(propyleneimine)(DAB-dendr(NH2)x) are reported. 4-(4-n-Alkoxybenzoyloxy)salicylaldehydes are used as mesogenic moieties attached at the peripheral amino groups of the dendrimers giving rise to dendromesogens with four and eight mesogenic branches. From these dendromesogens, considered as organic ligands, were prepared six metal-containing dendrimers which incorporate two or four copper atoms in their structures. All the dendrimeric ligands and three of the metal-containing dendrimers exhibit liquid crystalline properties which were studied by optical microscopy, DSC, X-ray diffraction and EPR spectroscopy.  相似文献   

15.
用电势阶跃法和旋转圆盘电极法(RDE)以及SEM和XRD测试手段,初步研究了光亮剂双氰化体系中银电沉积行为的影响,研究表明,光亮剂的加入并未导致银电沉各成核机理的改变,但显著增强了镀液的微观平整效应,并且所得镀层的表现光滑程度明显改善,XRD测试亦同时表光亮剂的加入并未改变镀层的择优取向。  相似文献   

16.
The dependence of the critical supersaturation on the degree of the initial undersaturation has been analyzed in detail.This dependence is explained by means of the Richarch-Powell equation, taking into account the dependence of the -ratio upon the partial pressures of the inert gas and the liquid under investigation.  相似文献   

17.
An approximated hardness kernel, which includes the second derivative with respect to the density of the kinetic energy, the electron-electron coulomb repulsion, and the exchange density functionals, has been tested for the calculation of the global hardness. The results obtained for a series of 40 cations and neutral systems and 16 anions represent in most cases an improvement of the results obtained using the HOMO-LUMO gap approach and indicate the viability of this approach to evaluate global hardness. In addition, the relevance of the Fukui function approximation and the role of the three components of the hardness kernel in the evaluation of the global hardness have been analyzed.  相似文献   

18.
Abstract

Thermodynamic and transport properties of pure liquid metals show interesting correlations near the melting temperature. This is well known for the case of the surface tension σ and the shear viscosity η In this paper we investigate the possible extension of these correlations to binary alloys, taking the FeB alloy as a case study. Based on literature data we analyze the variation of σ and η as a function of temperature and concentration in a deep eutectic region of the phase diagram of this alloy, as well as the possible correlations between those two quantities. Substantial differences with respect to the behavior in pure metals are found.  相似文献   

19.
A straightforward modification of the resolution of the identity (RI) approximation to the Coulomb interaction is described. In the limit of basis sets that are dominated by high angular momentum functions the observed speedups in realistic test systems reach a factor of 2 compared to the standard RI algorithm, and a factor of up to 300 compared to the standard algorithm to form the Coulomb matrix. More moderate savings on the order of 0-20% are obtained for the more commonly used smaller basis sets. A series of test calculations is reported to illustrate the efficiency of the algorithm.  相似文献   

20.
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