分光光度法研究水-乙醇体系析相萃取分离和富集PdBr2-4

用可见分光光度法研究了水-乙醇体系析相萃取分离和富集PdBr42-的行为及与一些金属离子分离的条件.结果表明,(NH4)2SO4能使乙醇的水溶液分成两相,在分相过程中,Pd(Ⅱ)与KBr生成的PdBr42-与质子化乙醇(C2H5OH2+)形成的缔合物[PdBr42-][C2H5OH2+]2能被乙醇相完全萃取.当乙醇、K...     

分光光度法研究水-乙醇体系析相萃取分离和富集PdBr_4~(2-)

用可见分光光度法研究了水-乙醇体系析相萃取分离和富集PdBr42-的行为及与一些金属离子分离的条件.结果表明,(NH4)2SO4能使乙醇的水溶液分成两相,在分相过程中,Pd(Ⅱ)与KBr生成的PdBr42-与质子化乙醇(C2H5OH2+)形成的缔合物[PdBr42-][C2H5OH2+]2能被乙醇相完全萃取.当乙醇、KBr和(NH4)2SO4分别为30%、6.0×10-3 mol/,L、0.3 g/mL,pH 3时,PdBr42-的萃取率达到98.6%以上,Fe(Ⅲ),Al(Ⅲ),Cr(Ⅲ),Ag(Ⅰ),Cu(Ⅱ),Ni(Ⅱ),Zn(Ⅱ),Co(Ⅱ),Mn(Ⅱ),V(Ⅴ),U(Ⅵ),Pb(Ⅱ),Ru(Ⅲ),Rh(Ⅲ)和Hg(Ⅱ)基本不被萃取,实现了Pd(Ⅱ)与上述金属离子的分离.     

硫酸铵存在下碘化钾-乙醇体系萃取分离镉

传统萃取分离法由于采用与水互不相溶的有机溶剂 ,对那些萃取反应速度慢、传质速率低、分配比小的体系需在振荡器上进行较长时间振荡或多次萃取才能达到定量萃取 .均相萃取、异相分离萃取体系由于可以克服异相萃取分离技术中一些缺点而受到重视[1,2 ].本文以乙醇为溶剂 ,均相萃取、异相分离镉 .试验表明 ,硫酸铵存在下 ,乙醇与水分相过程中 ,Ｃｄ(Ⅱ )与Ｉ- 形成的ＣｄＩ2 - 4 与质子化乙醇 (Ｃ2 Ｈ5ＯＨ 2 )形成电中性缔合物 (Ｃ2 Ｈ5ＯＨ 2 ) 2 ＣｄＩ2 - 4 被乙醇相完全萃取 .能使Ｃｄ(Ⅱ )从Ｆｅ(Ⅲ )、Ｃｏ(Ⅱ )、Ｎｉ(Ⅱ )、Ｍｎ(Ⅱ )…     

KBr-水-正丙醇体系中析相萃取分离富集Hg(Ⅱ)

研究了KBr-水-正丙醇析相萃取Hg(Ⅱ)的行为及与一些金属离子分离的条件.结果表明,( NH4)2SO4能使正丙醇的水溶液分成两相,在分相过程中,Hg(Ⅱ)与KBr生成的HgBr42 -与质子化正丙醇(C3H7OH2+)形成的缔合物[HgBr42-] [C3H7OH2+]2能被正丙醇相完全萃取.当溶液中KBr、( N...     

硫酸铵-碘化钾-乙醇体系萃取分离铋

1　引言利用高聚物水溶液在无机盐存在下可以分成两相的非有机溶剂萃取分离方法已引起人们的重视[1 ,2 ] 。本文研究发现 ,在硫酸铵存在下 ,乙醇与水分相过程中 ,Ｂｉ(Ⅲ )与Ｉ- 形成的ＢｉＩ3-6 络阴离子能被乙醇相定量萃取 ,控制一定的酸度 ,可以实现Ｂｉ(Ⅲ )与Ｆｅ(Ⅲ )、Ｃｏ(Ⅱ )、Ｍｎ(Ⅱ )、Ｃｕ(Ⅱ )、Ｎｉ(Ⅱ )、Ｍｏ(Ⅵ )之间的分离。该萃取体系与传统的有机溶剂萃取分离方法相比 ,具有平衡时间短 ,相分离速度快 ,无三相乳化 ,不使用有毒害有机溶剂 ,操作简单 ,快速均相萃取 异相分离等优点 ,既能萃取离子缔合物 ,又能萃取络阴…     

氯化钠-碘化钾-丙醇体系萃取分离汞

在无机盐存在下 ,乙醇水溶液可以分成液 -液两相 [1] .我们通过研究发现 ,在丙醇水溶液中加入无机盐 ,丙醇与水也能分成液 -液两相 .金属离子的缔合物可以在丙醇 -水两相中进行分配 ,其分离操作方式及萃取分离的特点类似于乙醇体系 ,即以丙醇作为萃取溶剂建立均相萃取、异相分离的萃取体系 .本文研究表明 ,在丙醇与水分相条件下 ,Hg( )与 I- 形成的 Hg I2 - 4能被丙醇相萃取 ,控制一定的酸度 ,能使 Hg( )从 Fe( )、Co( )、Ni( )、Mo( )、Mn( )、Zn( )的混合液中分离出来 .正丙醇和氯化钠均为 AR级 ,北京化工厂产品 ;碘化钾 ,A…     

用Tween 80-硫酸铵-1-(2-吡啶偶氮)-2-萘酚-磺酸体系萃取分离钯(Ⅱ)、钴(Ⅱ)、镍(Ⅱ)、锌(Ⅱ)、镉(Ⅱ)、锰(Ⅱ)和铝(Ⅲ)

研究了Tween 80水溶液在(NH4)2SO4存在下,水溶性螯合剂1-(2-吡啶偶氮)-2-萘酚-磺酸与金属离子螯合物在该体系中两相间的分配行为.结果表明,Pd(Ⅱ)、Co(Ⅱ)在pH 2.0～3.5缓冲溶液中可被Tween相完全萃取,而Zn(Ⅱ)、Cd(Ⅱ)、Mn(Ⅱ)、Al(Ⅲ)基本上不被萃取.在不同pH条件下实现了Pd(Ⅱ)、Co(Ⅱ)、Ni(Ⅱ)、Zn(Ⅱ)、Cd(Ⅱ)、Mn(Ⅱ)、Al(Ⅲ)混合离子的定量萃取分离.     

乙醇-盐-水-5-Br-PADAP体系萃取分离测定钯

研究了在硫酸铵存在下 ,5 Br PADAP乙醇体系中Pd(Ⅱ )、Rh(Ⅲ )、Pt(Ⅳ )的萃取行为及乙醇溶液的分相条件 ,讨论了影响萃取率的各种因素 ,试验表明 ,室温下 ,一定 pH范围内 ,该体系中的Pd(Ⅱ )几乎可完全被乙醇相萃取 ,而Rh(Ⅲ )、Pt(Ⅳ )不被萃取或萃取率很低 ,从而可实现Pd(Ⅱ )、Rh(Ⅲ )、Pt(Ⅳ )混合离子的定量分离 ,同时建立了Pd(Ⅱ )的测定方法。乙醇相中Pd(Ⅱ ) 5 Br PADAP配合物表观摩尔吸光系数为 1.18× 10 5L·mol- 1·cm- 1,钯量在 0～ 9.6 0 μg/10ml范围内符合比耳定律 ,检出限为 0 .0 90 μg/10ml。用该法分离混合样和测定两种活性碳钯催化剂中钯 ,结果满意     

聚乙二醇-硫酸铵-二甲酚橙体系萃取分离钯

研究了萃取剂二甲酚橙与Pd(Ⅱ)离子的螯合物在聚合物-硫酸铵-水体系中两相间的分配行为。在pH1．0～6．0条件下，Pd(Ⅱ)几乎被二甲酚橙完全萃取到PEG相中，而Fe(Ⅱ)、Co(Ⅱ)、Zn(Ⅱ)萃取率随pH变化显著，Mn(Ⅱ)、Cd(Ⅱ)基本不被萃取。在HClO4介质pH1．0～2．0条件下，实现了Pd(Ⅱ)与Fe(Ⅱ)、Co(Ⅱ)、Zn(Ⅱ)、Mn(Ⅱ)、Cd(Ⅱ)的定量萃取分离。     

硫酸铵-3，5-二溴水杨基荧光酮-乙醇体系萃取分离钼

在含有一定浓度硫酸铵的条件下,乙醇水溶液能形成盐水与乙醇液-液两相,研究了Mo(Ⅵ)与3,5二溴水杨基荧光酮(DBSAF)形成的配合物在乙醇盐水萃取体系液-液两相中的分配行为.试验表明,在PH 1～6范围内,硫酸铵浓度为350 g·L-1,试液中乙醇与水的体积比为3比7,1×10-4mol·L-1 DBSAF溶液加入量为2 mL及试液总体积为10 mL的条件下,Mo(Ⅵ)均保持很高的萃取率,用控制酸度的方法实现了Mo(Ⅵ)与常见过渡元素离子Co(Ⅱ)、Zn(Ⅱ)、Ni(Ⅱ)、Cu(Ⅱ)、Mn(Ⅱ)、Fe(Ⅲ)、W(Ⅵ)的定量分离,试验了钼(Ⅵ)与上述各共存离子的分离,钼(Ⅵ)的萃取率均大于97%,而其他共存离子的萃取率均小于5%.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Acid hydrolysis of carboxymethylcellulose of low degree of substitution

Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。     

Estimation of Kinetic Parameters of Thermal Oxidation of Ilmenite

The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe₂O₃. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mechanism of action of base-catalyzed oxygenation of phenol derivatives

Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

化学计量中不确定度评定研究进展

测量不确定度是表征合理地赋予被测量之值的分散性的参数。本文针对化学计量不确定度评定基础模型仅适用于线性模型、概率分布为正态分布或缩放位移t分布等局限,介绍了近年来不确定度评定的研究热点:蒙特卡罗方法(Monte Carlo Method,MCM),不确定度评定的来源、评定概念、评估方法及其发展过程,扩大了测量不确定度评定与表示的适用范围。     

微量钙的测定方法研究进展

介绍了1995-2006年期间测定微量和痕量钙的方法,如电感耦合等离子体-原子发射光谱法、原子吸收光谱法以及离子色谱法等的工作原理和特点,并说明了其测定微量钙的应用领域。并对微量钙的测定技术进行了展望(引用文献55篇)。     

Stages of thermal decomposition of sodium oxo-salts of sulphur

Thermal behaviour of sodium oxo-salts of sulphur: Na₂SO₄, Na₂S₂O₇, Na₂S₂O₆, Na₂SO₃, Na₂S₂O₅, Na₂S₂O₄, Na₂S₂O₃, Na₂S₃O₆ and of sulphides Na₂S and Na₂S₂ was studied on heating up to 1000°C. The experiments were performed with anhydrous compounds obtained from commercial products by recrystallisation and dehydration. The stage mechanisms of decomposition of anionic sub-lattices of the salts have been proposed basing on the Górski’s morphological classification of simple species. The thermal stability and the stage decomposition mechanisms were correlated with the structure and the potential chemical properties of the salt anions. The thermal decomposition processes were studied by means of thermal analysis, and the decomposition products were identified by means of X-ray phase analysis.