流动注射—分光光度法测定植物中钼

本文将流动注射分析(FIA)引入Mo-SCN~--RhB三元缔合体系测定痕量Mo。不需萃取,反应迅速,重现性好。0～1.6μg/ml Mo符合比耳定律,检测限0.02μg/ml。用预混线圈R_1可克服Fe~(3+)等元素与SCN~-络合的干扰。测定了植物中Mo,结果满意。     

二氯荧光素-氯化十六烷基吡啶荧光猝灭法测定微量碘

本文研究了用二氯荧光素(DCF)-氯化十六烷基毗啶(CPC)体系荧光猝灭法测定微量碘。在pH为2.8～3.1的H_2SO_4介质中,检出限为0.30μg/25ml,线性范围为0.30～2.00μg/25ml。本法灵敏度高,选择性好,适用于微量碘的测定。     

3,5-二溴-PADAP分光光度法测定微量SCN-离子的研究

酸性介质中,显色剂3,5-二溴-PADAP与IO_3~-离子和SCN~-离子形成深蓝色的三元离子缔合物,其表观摩尔吸光系数为2.7×10~4L(mol·cm),提出了测定微量SCN~-离子的新方法,并用于唾液及尿液中SCN~-含量的测定。     

钌(Ⅲ)-过硫酸钾-氨基黑10B体系催化分光光度法测定微量钌的研究

本文首次发现钌(Ⅲ)对K_2S_2O_8氧化氨基黑10B褪色反应有显著催化作用并以此反应为指示反应建立了测定微量钌的催化分光光度法。该方法的检测限为0.02μg/ml,在0.030～0.30μg/ml范围内呈线性关系。该方法已用于贵金属精矿及氯化渣中微量钌的测定,结果令人满意。     

硫氰酸根-吡啰红G荧光光度法测定水及尿样中微量钼

本文利用吡啰红G作为荧光试剂,在强酸性条件下,用丙酮作增溶剂,硫脲作还原剂,Cu~(2+)作催化剂,使Mo(Ⅵ)还原为Mo(Ⅴ)并与SCN~-和试剂形成离于缔合物.该缔合物的荧光强度在测定条件下与钼的浓度成正比,λ_(?)=528/552nm;此法灵敏度高,选择性好,线性范围为0.0～1.4μg/25ml.直接用于自来水和尿样中钼的测定,回收率在97%～105%之间,结果满意.     

利血平的光化学荧光特性及其应用

在10％HAc介质中,利血平经紫外光照射时,其光化学反应产物具有强烈荧光(λ_(ax)=385 nm,λ_(ax)=490 nm)。利血平浓度在0.01～0.30μg/ml范围内,荧光强度与浓度呈良好的线性关系,由此建立了利血平的光化学荧光测定法。方法的检出限为1.3 ng/ml,相对标准偏差为1.6％。本法简便快速且灵敏度高,可用于片剂及注射液中利血平含量的测定。     

以聚氯乙烯-双硫腙-铜络合物为载体的长寿命硫氰酸根离子选择电极

报道了以PVG-双硫腙（DTZ）-Cu（Ⅱ）,PVC-DTZ-Cu（Ⅰ）为载体制备了性能良好的SCN-离子电极,其选择性次序为SCN~-》ClO_4~->Sal~-》NO_3~-~Cl~->PO_4~(2-)。16℃时,膜组成为PVC－DTZ-Cu（Ⅰ）：PVC：邻硝基苯基辛醚（o-NPOE）＝12∶22∶66的SCN~-离子电极,在0．02mol/LHCl体系中,在1×10~(-2)~5×10~(－6)mol/LSCN~-浓度范围呈能斯特响应,斜率为58±2mV/dec,检测限为2×10~(-6)mol/L;膜组成为PVC-DTZ-Cu（Ⅱ）∶PVC∶o-NPOE∶四苯硼酸钾（KTPB）为8∶22∶55∶15的电极,在0．01mol/LHAc-NaAc缓冲体系中,在10~(-2)~2×10~(-6)mol/LSCN~-浓度范围呈线性响应,斜率为54∶1mV/dec,检测限为8×10~(－7)mol/L.研究了阴离子与载体作用的机理,表明SCN~-与载体中铜原子直接作用。电极应用于废水中SCN~-的测定,结果令人满意。     

铜电极上CN-、SCN-电化学行为的现场红外反射吸收光谱研究

本文用循环伏安法和现场红外光谱方法研究了铜电极上CN~-和SCN~-的电化学行为。对于0.5mol~(-1)L~(-1)NaCN+0.5 mol L~(-1)NaF/Cu体系, 电极电势在-1.60至0.30 V(相对SCE)范围内, 2030—2230 cm~(-1)范围内可得到三个吸收峰, 位置分别为2076, 2094和2170 cm~(-1)。2076和2170 cm~(-1)峰分别对应于溶液中CN~-和表面沉积难溶化合物CuCN。2094 cm~(-1)峰是吸附态CN~-和溶液中配合物Cu(CN)_3~2二物种的红外吸收叠加。对于0.5 molL~(-1)NaSCN+0.5 molL~(-1)NaF/Cu体系, 在上述电势范围内可得到2060, 2177和2170 cm~(-1)三个红外吸收峰, 分别对应于溶液中的SCN~-, 吸附态的SCN~-和表面难溶化合物CuNCS。     

高灵敏分光光度法测定食品中痕量硒—硫氰酸盐—罗丹明B—Tween20体系

本文研究了Se(Ⅳ)-SCN-RhB-吐温20高灵敏显色反应体系。Se(Ⅳ)与SCN~-和RhB~+形成三元离子缔合物,并吸附了染料琉氰酸盐,表观摩尔吸光系数2.0×10~6L·mol~(-1).cm~(-1),是碱性染料类分光光度法中最灵敏的。Se含量在0～2μg/25ml范围内遵从比尔定律。利用巯基棉分离干扰离子,选择性高。测定了食品中总硒,结果满意。     

水、尿及血清中氰化物及硫氰酸盐共存时的分别测定方法(吹气—吡唑啉酮异菸酸法)

当水、尿及血清中同时存在有氰化物及硫氰酸盐时,采用一般的方法是难以将二者分别测定的。Baar及Feldstein等曾介绍过微扩散法,可以分别测定CN~-及SCN~-,但需用特制玻璃仪器,且操作不便。我们根据氰化物在酸性溶液中极易逸出的特点,拟定了用氮气或空气将酸性溶液中的CN~-吹出,用稀NaOH溶液吸收的方法使CN~-和SCN~-分开而测定的方法。实践证明,本法简便,效果良好。近年来测定氰化物大都采用吡唑啉酮     

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.     

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。     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

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.     

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^-。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

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.