硅钼黄和硅钼蓝测定三元复合驱采出水中硅的比较

三元复合驱采出水中硅含量的测定分别采用硅钼黄分光光度法和硅钼蓝分光光度法,并对两种测试方法进行了比较。实验结果表明,当样品的硅离子浓度较低时,采用硅钼蓝法的精密度要高于硅钼黄法。当硅离子浓度较高时,硅钼黄法精密度高于硅钼蓝法。因此,建议在测试三元复合驱采出水硅含量时,可根据样品的硅含量选取适当的分析方法。     

硅钼杂多酸光度法测定药物中青霉胺

建立了准确、简便、快速的硅钼杂多酸光度法测定青霉胺的新方法,详细探讨了硅钼杂多酸光度法测定青霉胺的各种影响因素。结果表明,在最佳条件下,SiO_3~(2-)与Mo_7O_6-24反应生成的硅钼杂多酸[H4Si(Mo_3O_(10))_4]被青霉胺分子中的巯基(—SH)还原为硅钼蓝[H4Si(Mo_3O_(10))_2-(Mo_3O_9)_2],在最大吸收波长730nm处通过测定硅钼蓝的吸光度,可间接测定青霉胺的含量。该方法用于青霉胺片中青霉胺的含量测定,其结果与药典法一致。     

铜冶炼系统物料测定硅的几种方法概述

在铜冶炼系统当中,铜精矿,辅料石英石及铜炉渣都是含硅的复杂化合物,准确测定硅的含量对铜冶炼生产至关重要。简要阐述了硅酸脱水重量法、氟硅酸钾容量法及硅钼杂多酸光度法测定硅的方法原理及相关注意事项。在实际分析工作当中,应根据物料含硅量不同,选择合适的方法,就能得到准确的结果。     

无机阻燃剂发展现状

无机阻燃剂包括氢氧化铝、氢氧化镁、无机磷、硼酸盐、氧化锑、钼化合物、锡化合物、无机硅等。文章介绍了阻燃剂和无机阻燃剂的分类和阻燃机理,并着重介绍了氢氧化铝、氢氧化镁、无机磷、硼酸盐、氧化锑等几种无机阻燃剂的性能、阻燃机理、应用及发展现状,分析了存在的问题,并对今后阻燃剂的发展方向和研究方向提出了建议。     

硅钼蓝光度法快速测定SAPO-34分子筛中硅含量

建立一种以分光光度法测定SAPO-34分子筛中硅含量的分析方法。以硅和钼酸铵在盐酸介质中形成硅钼黄杂多酸,再以抗坏血酸将硅钼黄还原成硅钼蓝后,对硅含量进行测定。结果表明,体系中硅钼蓝的最大吸收波长为806 nm,绘制的标准曲线在0.100 0~6.000 mg/L内服从朗伯-比尔定律,所得相关系数为R2=0.999 5。该分析方法用于SAPO-34分子筛中硅含量的测定,精密度及稳定性良好,操作简单、快速。     

含硅化合物肥料

本文对几种含硅化合物肥料作了简要介绍。含硅化合物肥料施用于稻谷，一般可增产１０％左右。我国应大力发展含硅化合物肥料。     

α-硅钼黄吸光光度法测定陶瓷粉笔中高含量硅

基于α型硅钼黄比β型硅钼黄更稳定，且灵敏度更低，有利于高含量硅的比色测定的特点，建立了α-硅钼黄吸光光度法测定陶瓷粉笔中高含量硅的分析方法。试验结果表明：α型硅钼黄比β型硅钼黄吸光光度法稳定性和准确性都有较大提高，可用于陶瓷粉笔中高含量硅的日常快速测定。     

非离子表面活性剂存在下结晶紫-硅钼杂多酸退色机理的研究

研究了非离子表面活性剂对结晶紫-硅钼杂多酸显色反应的影响。研究结果表明,非离子表面活性剂醚氧原子的质子化作用导致生成(钅羊)离子,与硅钼杂多酸缔合,形成一种离子缔合物。所以,非离子表面活性剂存在下,结晶紫-硅钼杂多酸的退色现象,可归结于竞争反应。退色速度随氢离子浓度的增加而加快。     

硅钼蓝分光光度法测定磷矿石中的二氧化硅

对硅钼蓝分光光度法测定磷矿石中的二氧化硅进行了研究。研究了硅钼黄的显色条件及干扰因素,在本方法试验控制Ｈ２ＳＯ４浓度范围内硅与钼酸钠生成硅钼黄,经ＦｅＳＯ４还原成硅钼蓝,ＳｉＯ２含量在０～６００μｇ／１００ｍｌ范围内服从比耳定律。操作简便,重现性好,结果准确,测定磷矿石中的二氧化硅含量,结果满意。     

还原硅钼酸盐分光光度法测定偏钒酸铵中硅的含量

介绍了还原硅钼酸盐分光光度法测定偏钒酸铵中的硅含量 ,讨论了吸收波长、还原剂、酸度及掩蔽剂加入量等因素对测定结果的影响。结果表明 ,还原硅钼酸盐分光光度法测定偏钒酸铵中的硅含量 ,数据准确     

非诱变性间苯二胺衍生物的合成工艺研究

由 2 ,4-二硝基氯苯出发 ,经亲核取代、加氢还原两步合成了三种非诱变性间苯二胺衍生物 :2 ,4-二氨基苯丙醚 ,2 ,4-二氨基苯丁醚和 2 ,4-二氨基苯基 -β-羟乙基醚。在合适的反应条件下 ,合成这三种化合物的总产率分别为 91 .0 % ,90 .8%和 74.1 %。所合成的三种二胺化合物可替代间苯二胺用于染料的生产     

三种理气类中药挥发性成分的GC-MS分析

研究了三种(厚朴、檀香、木香)理气类中药挥发油的化学成分。用水蒸气蒸馏提取三种药材的挥发油,用GC-MS分离检测其化学成分,并结合气相色谱程序升温指数辅助定性确定出挥发油中的化学组分。鉴定出木香挥发油中29个成分(占挥发油总量的92.00%);厚朴挥发油中26个成分(占挥发油总量的91.88%);檀香挥发油中10个成分(占挥发油总量的94.51%),三中药物挥发油的主要成分大不相同。计算了各种化合物的保留指数,使用保留指数辅助定性鉴定出的化合物所占挥发油百分含量明显多于文献中所报道的数据。     

Empirical and theoretical investigations on the corrosion inhibition characteristics of mild steel by three new Schiff base derivatives

Synthesis, adsorption and corrosion inhibiting effect of three new Schiff base compounds on mild steel in 1.0?M HCl were explored using weight loss, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization techniques. The empirical results showed that three Schiff base compounds inhibited the corrosion reaction in aggressive acid medium. Impedance results indicate that the three organic compounds were adsorbed on the mild steel/solution interface, while polarization data show that the three compounds performed typically as a mixed-type inhibitor. A theoretical study of the adsorption performance of some of the components of Schiff base inhibitors was carried out in the basis of the density functional theory (DFT) and Monte Carlo simulations.     

喷气燃料中活性硫化物来源与腐蚀性研究

对生产和运输过程中喷气燃料活性硫化物产生的原因进行了分析,针对三种主要活性硫化物对喷气燃料银片腐蚀的影响进行了总结和归纳,分析了三种活性硫化物之间的相互影响关系,有利于下一步有针对性地开展活性硫化物的快速检测技术研究。     

2-芳氧基-1,8-邻苯二甲酰基萘的合成及光致变色性

合成了3种2-芳氧基-1,8-邻苯二甲酰基萘类光致变色化合物,通过核磁共振谱、红外光谱、质谱和元素分析确定了结构.对产物进行了荧光光谱测定,3种光致变色化合物的荧光强度和Stoke位移都较大.用紫外-可见分光光度计对其在丙酮溶液中的光致变色行为进行了测定,3种光致变色化合物在300—600 nm范围内都具有一定的光致变色性能和较大的吸光系数.     

The synthesis and characterization of N-(diphenylthiophosphinyl)-P-phenyl-thiophosphonamidic acid phenyl ester and related compounds chiral at phosphorus

The synthesis and spectroscopic characterization of three novel phosphorus(V) compounds, chiral at phosphorus, are reported. All three compounds were characterized by X-ray crystallography, and for one compound a ¹H–³¹P HETCOR experiment was performed.     

4,6-二甲氧基嘧啶衍生物的合成及生物活性测定

以4,6-二甲氧基-2-甲基磺酰基嘧啶为起始原料,采用中间体衍生化方法,合成了三类嘧啶类化合物.应用氢核磁共振、红外和元素分析验证了所合成化合物的结构.生物活性测试结果显示大部分化合物具有杀菌活性,其中化合物8在25 mg/L质量浓度下对水稻稻瘟病的抑制率达100%,化合物10c在400 mg/L质量浓度下对黄瓜霜霉病具有100%的防效.部分化合物具有一定的除草活性.     

Investigation of three types of catalysts for the hydration of ethylene oxide (EO) to monoethylene glycol (MEG)

Amine compounds, bi-functional compounds (EDTA, ethylene diamine tetra acetic acid type), and Salen compounds were investigated for catalytic hydration of ethylene oxide (EO) to monoethylene glycol (MEG). Many of the catalysts studied are selective for the formation of MEG compared with thermal hydration without any catalyst present. The results of the catalytic hydration with three types of catalysts were rationalized using acid and base catalyzed reaction mechanisms.     

The effects of certain ecdysteroids and inhibitory amines and amides on the metabolism of 22,25-dideoxyecdysone in cockroach organ cultures

An organ culture assay system using cockroach leg regenerates and fat body has been developed in which compounds that either inhibit molting hormone metabolism or act as molting hormone antagonists can be tested. Representatives of three classes of compounds were tested in the system: ecdysteroids, azasteroids, and nonsteroidal amines and amides. Inhibitory compounds were found in all three of the classes. Certain of these inhibitors represent a new class of insect hormonal compounds with a novel mode of action—the disruption of molting hormone metabolism.     

HPLC separation and wavelength area ratios of more than 50 phenolic acids and flavonoids

Relative retention times and wavelength area ratios for over 50 standard compounds were calculated using reverse-phase HPLC. The standard compounds analyzed included benzoic acids, cinnamic acids, benzene carboxylic acids, acetic acids, coumarins, benzaldehydes and a variety of flavonoid compounds including flavanones, flavones, isoflavones, and their glycosides. Each standard compound was chromatographed by three different gradient elutions. Compounds were detected by UV absorption at 254 nm and 280 nm. Relative retention times with respect to two different internal references and the 254nm: 280nm wavelength area ratio was determined for each standard. Soybean root and seed extracts were analyzed for the presence of the standard compounds using the chromatographic conditions described.