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1.
铝镁混合金属氢氧化物溶胶阴离子交换性能研究   总被引:10,自引:0,他引:10  
本文研究了电解质对铝镁混合金属氢氧化物(Al-MgMMH)溶胶粒子中Cl-和OH-的阴离子交换性能。在所研究的电解质NaNO3,HCOONa,CH3COONa,Na2CO3,Na2SO4和Na3PO4中,发现高价阴离子的交换能力大于低价阴离子的交换能力,无机阴离子的交换能力大于有机阴离子的交换能力。所研究Al-MgMMH溶胶粒子的阴离子交换容量为2.82mmol/g,比粘土粒子的阳离子交换容量大得多。  相似文献   

2.
以精制棉为原料,经过漂白→碱化→老化→黄原酸酯化制得粘胶液,按一定比例加以CaCO3粉末,混合均匀后分散在氯苯中90℃下加热固化3h,在HCl-NaCl-CaCl2混合溶液中除去CaCO3后,制得大孔球形纤维素。研究制球的各种影响因素。  相似文献   

3.
以精制棉为原料,经过漂白→碱化→老化→黄原酸酯化制得粘胶液,按一定比例加入CaCO3粉末,混合均匀后分散在氯苯中90℃下加热固化3h,在HCl-NaCl-CaCl2混合溶液中除去CaCO3后,制得大孔球形纤维素。研究了制球的各种影响因素。  相似文献   

4.
以NaOH,Na2CO3混合或以NH4OH,(NH4)2CO3混合液为沉淀制备了Mg/Al=3-6.7的Mg-Al为滑石。将水滑石在500-600℃下焙烧制得了具有与Mgo相同的晶体结构的Mg(Al)L复合氧化物,它们的比表面积大于或接近γ-Al2O3,而且具有良好的热稳定性。  相似文献   

5.
PdCl2在碱式纤维素基磁性聚偕胺肟树脂上的吸附行为与H2PdCl4不同,主要表现在高的超当量吸附。动力学研究表明,H2PdCl4在碱中和过程中逐步转变为Na2PdCl4、PdCl2、和[Pd(OH)2Cl2]2,它们被树脂吸附时首先形成AO-Pd2和AO2-Pd3络合物,随后被还原为单质钯,汇聚成微粒吸着在树脂表面。  相似文献   

6.
本文以正三辛基氧膦为萃取剂,以熔融石蜡为稀释剂,研究了HClO4-NaClO4介质中La^3+、Nd^3+、Sm^3+、Dy^3+Yb^3+的固--液萃取行为及萃取反应热力学性能。斜率比法给出萃合物组成为Ln(TOPO)2(OH)(ClO4)2。测定了萃取反应势力学参数、平衡常数及半萃取pH值。  相似文献   

7.
硼氢化钠还原法制备四羰基钴钠及羰基化反应   总被引:4,自引:1,他引:4  
李光兴  蔡晓江 《合成化学》1995,3(3):263-266
在常温压下,用NaBH4作还原剂,由CO与CoCl2反应制备Na[Co(CO)4],其最佳的原料配比为NaBH4:CoCl2=2.5:1,反应温度为0-5℃,反应时间为2h。产物经IR光谱鉴定,在1893cm^-1处有一强吸收峰,此峰为[Co(CO)4]^-络合物离子中M-CO的特征吸收峰。  相似文献   

8.
于琴萍  吕殿祯 《化学学报》1994,52(4):346-351
本在恒定特丁醇质量分数x=0.10的条件下,应用电动势测定了无液接界电池(A)和电池(B)的电动势:Pt,H2(1.013×10^5Pa)|HC(m),tert.-C4H9OH(x),H2O(1-x)|AgCl-Ag (A) Pt,H2(1.013×10^5Pa)|HCl(mA),NaCl(mB),tert.-C4HoOH,H2O(1-x)|AgCl-Ag (B)根据电池(A)电动势确定了  相似文献   

9.
溴化钠在正丙醇-水混合溶剂中溶解热和溶剂化热   总被引:2,自引:0,他引:2  
用高精度等温外壳式量热计测量了298.15K下NaBr在不同组成正丙醇水混合溶剂中溶解热。根据测量结果及以前作者对NdCl3,BaCl2,NaCl,NaI,NaF/m-C3H7OH-H2O体系溶解热的研究结果,计算了298.15K下,正丙醇水混合溶剂中,上述盐的标准溶解热和NaF,NaCl,NaBr的NaI的溶剂化热,讨论了电解质溶解热和溶剂化热与离子特性、混合溶剂的组成和结构的关系。  相似文献   

10.
5-芳基-2-呋喃甲酸及其衍生物具有调节植物生长等作用[4].我们通过大量的实验,选用PTC法,利用5-芳基-2-呋喃甲酰氯与芳胺和芳氧基乙酰肼反应,合成了新化合物Ⅱ和Ⅳ:RCOClO(Ⅰ)ArNH2/PEG-400→RCONHAr(Ⅱ)ONaOH/...  相似文献   

11.
Abstract— The photoreduction of thiazine dyes by ethylene diamine tetraacetic acid (EDTA) was investigated by Rash photolysis. This reaction was found to occur according to a three-step mechanism. the first being the formation of the dye triplet state followed, in weakly acid solutions, by protonation. During the second step, the triplet state of the dye disappears through two competing processes: spontaneous deactivation and reaction with EDTA, which leads to the semireduced dye. The third step leads to the leucodye. It is shown that the overall quantum yield of photoreduction is governed by the second step and can be calculated from the ratio of the rate constants of the two elementary processes involved in this step. This ratio was measured over a wide pH range.  相似文献   

12.
研究了在 0.10 mol·L-1的盐酸介质中,亚硝酸根催化溴酸钾氧化伯胺基结构碱性染料吖啶黄褪色反应的适宜条件与影响因素,建立了催化动力学褪色光度法测定痕量亚硝酸盐的新方法。亚硝酸根浓度在0.25~20.00μg/25 mL范围内符合比耳定律,其λmax=455nm,Sandell灵敏度为36.20 ng·cm-2,RSD为1.15%~5.97%,回收率为 97.5%~105.0%。方法用于环境样品、生物材料、食品等实际样品中亚硝酸根的测定,试剂简单,方法快速,选择性好,结果满意。  相似文献   

13.
硫酸根的分光光度法测定   总被引:6,自引:0,他引:6  
本文就硫酸根的间接及直接光度测定的基本原理,试剂,方法和应用等作了较为系统的评述。列出重要文献67篇。  相似文献   

14.
SITES OF PHOTOSENSITIZATION BY DERIVATIVES OF HEMATOPORPHYRIN   总被引:2,自引:1,他引:2  
Leukemia L1210 cells were incubated in vitro with the tumor-localizing product HPD (hem-atoporphyrin derivative) for 0.5. 4 and 18 h. Effects of subsequent irradiation on viability, membrane transport and integrity, DNA synthesis and intracellular ATP concentration were assessed. Intracellular porphyrin pools were analyzed by HPLC. A 30 min incubation led to concentration of a readily-exchangeable pool of monomeric HPD components at plasma membrane loci; irradiation resulted in photodamage to membrane transport and a loss in capacity for dye exclusion. In contrast, increasing the incubation time led to a corresponding increase in the size of a non-exchangeable intracellular pool of other HPD components. Subsequent irradiation led to depletion of intracellular ATP and loss of capacity for biosynthesis of DNA, but little plasma membrane damage.  相似文献   

15.
离子交换法提取L-苯丙氨酸的研究   总被引:3,自引:0,他引:3  
本文介绍一种用离子交换树脂提取L-苯丙氨酸的方法,针对本研究体系得出的最佳工艺条件为:用001×7阳离子交换树脂吸附L-苯丙氨酸,以浓度为0.5%氨水进行洗脱,收集的流份经D354阴离子交换树脂脱色,浓缩结晶后得L苯丙氨酸成品,总提取收率为80%。  相似文献   

16.
膨润土吸附氨基酸研究   总被引:9,自引:0,他引:9  
本文用钠、钙两种类型膨润上对四种不同性质氨基酸进行了静态吸附试验,并对膨润土吸附氨基酸有关因素进行了研究。试验证明:钙膨润土吸附氨基酸能力较强,酸处理膨润土吸附性最好,等电;点时吸附量最大。在浓度为500mg·L-1pH=7溶液中,酸处理膨润土吸附赖氨酸可达200mmol·100g-1。  相似文献   

17.
阻抑氧化藏红T动力学光度法测定痕量铱   总被引:5,自引:0,他引:5  
基于在稀硫酸介质中,痕量铱对溴酸钾氧化藏红T褪色反应的阻抑作用,建立了一个测定痕量铱的动力学光度法。非催化体系与催化体系在530nm波长处的吸光度差值与铱的浓度在0.08~0.18μg/25ml范围内呈良好的线性关系,检出限为7.03×10-11g·ml-1。对0.15μg/25ml铱(Ⅳ)测定11次的相对标准偏差为0.36%。方法用于冶金产品及岩矿中铱测定的相对标准偏差为1.02%~1.88%,加标回收率为98.6%~102.4%。  相似文献   

18.
Abstract —The photoreduction of thionine by water has been studied, using a technique applied in earlier work on photoreduction of methylene blue. It is found for thionine as for methylene blue, that a long-lived excited intermediate is formed, and that two such intermediates react to produce a single reduced molecule, thus providing adequate energy for the reaction. The mechanism proposed for methylene blue photoreduction is shown to be applicable to thionine photoreduction as well, indicating the unimportance of the amine methyl groups. Although in previous work it was suggested that H2O was the reducing agent, none of them, however, could determine the H2O2 formed. The formation of H2O2 is confirmed in this work, and the kinetics of its formation are shown to be in accordance with the mechanism.  相似文献   

19.
DETERMINANTS OF PHOTOSENSITIZATION BY PURPURINS   总被引:1,自引:0,他引:1  
The human colon adenocarcinoma cell line, WiDr, was exposed to Photofrin II, hematoporphyrin derivative (HPD), hematoporphyrin (HP) or tetrasodium-meso-tetra(4-sulfonatophyenyl)porphine (TPPS4) followed by irradiation with light. Clonogenicity was determined and the resultant survival curves compared and shown to be qualitatively similar in shape. However, for equal amounts of drug in the medium, there were large differences in photosensitizing efficiency with Photofrin II approximately 5, 25 and 50 fold more effective than HPD, HP and TTPS4, respectively. For the same power used, all drugs were less efficient photosensitizers under red light (600-1100 nm) than under white light (300-110 nm). For all drugs this could be explained in terms of changes in light absorption over the two wavelength ranges. Differences in clonogenic cell survival could not be explained in terms of differences in singlet oxygen production (from published values). A reduction in drug uptake into the cells was sufficient to explain the differences between Photofrin II, HPD and HP, while TPPS4 was 5-fold less effective compared to other drugs than would be expected from drug uptake measurements. Two methods for measuring drug uptake were compared and shown to give different results for Photofrin II. Measurements of drug fluorescence in 0.1 N NaOH yielded 5-fold lower values than when measurements were in 1 N HCl following heat treatment to monomerise aggregated drug. Clearly the reliability of the method used in determining drug uptake must be carefully ascertained.  相似文献   

20.
Abstract

An unexpected nmr spectrum of β-phenyl ethyl thiocyanate in CDCl3 solution has led to its analysis in a series of solvents of increasing polarity. Changes in polarity produce increments of δAB, transforming the signal from a singlet for 4 methylenic protons to a clear A2B2 pattern. Signals appear to split following increasing values of dielectric constants and dipole moments. Rotational isomerism is assumed to be the reason for it since the reaction field parameter depends directly on the dipole moments of rotamers, thus changes in their population affect the reaction field and ultimately the chemical shifts.  相似文献   

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