极谱络合催化波测定钯

在Na2 CO3 NaHCO3 (pH 8.6 )缓冲溶液中 ,钯 与 8 羟基喹啉 5 磺酸形成的络合物在有阴离子表面活性剂十二烷基硫酸钠存在时 ,于 - 0 .72V(vs.SCE)处有一个二阶导数极谱波 ,与没有十二烷基硫酸钠存在时相比 ,峰电流增敏约 30倍 ,钯 浓度在 7.5× 10 -9～ 2 .8× 10 -6mol/L范围内 ,i″p 与钯 的浓度呈线性关系 ,检出限为 2 .8× 10 -9mol/L ,方法用于催化剂和工业废水中钯的测定 ,结果满意     

铋(Ⅲ)-8-羟基喹哪啶体系极谱行为——表面活性剂增敏机理和分析应用——Ⅱ.铋(Ⅲ)-8-羟基喹哪啶络合物电极反应和十二烷基苯磺酸钠增敏机理

试验表明,铋(Ⅲ)-8-羟基喹哪啶(8-OXQ)络合物(pHll,-0.60V)的峰电流(p)具吸附特性,为准可逆电极反应过程,其电子转移数(n),传递系数(α)及饱和吸附量(Γ_ο)分别为3,0.45,6.5×10~(-12) mol/cm~2。加入十二烷基苯磺酸钠(SDBS)未形成三元络合物,因SDBS的超载强烈吸附,引起诱导吸附,电双层结构激烈变化,而使电流峰形巨变,电流峰高(i_p)增大10余倍。讨论并指出SDBS对Bi(Ⅲ)与8-羟基喹啉(8-OX)及衍生物络合吸附电流增敏或抑制,与试剂组分、结构、解离态及络合物存在状态、电荷数、符号有关。     

7-碘-8-羟基喹啉-5-磺酸与钒显色反应的研究及应用

在 0 .2 0mol·L- 1硫酸介质中 ,用过氧化氢作增敏剂 ,7 碘 8 羟基喹啉 5 磺酸 (Ferron)与钒 (Ⅴ )形成 1∶1的有色配合物 ,在 4 10nm处有最大吸收 ,其表观稳定常数为 4 .5× 10 3 ,摩尔吸光系数ε4 10 为 1.91× 10 3 L·mol- 1·cm- 1,钒浓度在 0 .10～ 2 0 .0 μg·ml- 1范围内符合比耳定律。该方法用于矿样中钒的测定 ,结果满意     

铅-二溴邻苯二胺双草酰胺酸酯络合吸附波研究及应用

在 0 .0 5mol/L氯乙酸 氯乙酸钠 (pH 3.0 )介质中 ,Pb2 + 与二溴邻苯二胺双草酰胺酸酯 (DBAC)生成络合物 ,并吸附于电极表面 ,于 - 0 .6 0V(vs.SCE)得到络合物吸附还原波。其二次微分极谱峰电流与Pb2 + 浓度在 2 .5× 10 -8～ 6 .0× 10 -6mol/L内呈良好的线性关系 ;检出限为 1.5× 10 -8mol/L。方法应用于陶瓷颜料、矿石、人发中微量铅的测定 ,结果满意。初步探讨了电化学反应机理     

配位吸附波同时测定PbA和InA

在 0 .0 5mol/L氯乙酸 氯乙酸钠 (pH 3.0 )介质中 ,Pb2 + 、In3 + 与二溴邻苯二胺双草酰胺酸酯 (DBAC)生成络合物 ,并吸附于电极表面 ,分别于 - 0 .5 0V、- 0 .6 3V(vs .SCE)得到络合物吸附还原波。其二阶导数峰电流与Pb2 + 、In3 + 浓度分别在 2 .5× 10 -8～ 6 .0× 10 -6mol/L、7.5× 10 -8～ 3.4× 10 -6mol/L内呈良好的线性关系 ;检出限分别为 1.5× 10 -8mol/LPb2 + 和 4 .5× 10 -8mol/LIn3 + 。应用于陶瓷颜料、矿石中微量Pb、In的测定 ,结果满意。     

镉(Ⅱ)-meso(4-磺基苯)卟啉络合物的极谱伏安行为

用紫外分光光度法和循环伏安法考察了镉与meso(4-磺基苯)卟啉在强碱性溶液中形成的络合物的特性.结果表明,加入Cd(Ⅱ)后该卟啉的索瑞特(Soret)吸收带发生发红移,循环伏安图上出现了新的还原峰,峰电位为-1.20V(vs.SCE),络合物的络合比为11,稳定常数β=1.19×107.本文还用多种电化学技术证明了络合物的还原峰电流具有吸附特征;用示波极谱法二阶导数波测试了峰电流与镉离子浓度的关系,结果表明镉离子在3×10-7～1×10-5mol/L的浓度范围内与络合物峰电流有良好的线性关系;并求得了电极反应的电子转移数为2.此外本文还对络合物的电极反应机理进行了探讨.     

甲氧基苯并噻唑偶氮-8-羟基喹啉-5-磺酸的合成及与钴的显色反应研究

合成了新显色试剂7-[6-甲氧基-(2-苯并噻唑偶氮)]-8-羟基喹啉-5-磺酸.该试剂在弱酸性(pH5.0)条件下,在有非离子表面活性剂存在时,与钴形成紫红色的络合物.其最大吸收波长λ_(max)=560nm,表观摩尔吸光系数为6.17×10~4L·mol~(-1)·cm~(-1).钴含量在0～8μg/10ml范围内服从比耳定律.应用拟定的方法测定了维生素B~(12)等试样中的钴,结果满意.     

5-(对羧基苯偶氮)-8-羟基喹啉与铋的显色反应研究及应用

研究了新显色剂 5 (对羧基苯偶氮 ) 8 羟基喹啉 (5 CPAHQ)与Bi(Ⅲ )的显色反应条件。在阳离子表面活性剂十六烷基三甲基溴化铵 (CTMAB)存在下 ,在 pH 4 .6～ 5 .8的缓冲介质中 ,显色剂与铋 (Ⅲ )形成稳定的橙红色络合物。络合物的ε4 98=9.8× 10 4 L·mol- 1·cm- 1。铋 (Ⅲ )含量在 0～ 14μg/ 2 5ml内符合比耳定律。考察了共存离子对测定的影响。应用该法直接测定了胃必治药片中铋的含量 ,结果满意。     

新试剂7-(2,4,6-三羟基苯偶氮)-8-羟基喹啉-5-磺酸光度法同时测定微量锆和铪

本文研究了新试剂7-(2,4,6-三羟基苯偶氮)-8-羟基喹啉-5-磺酸(THBAQS)与锆、铪的显色反应.酸性条件下锆、铪均可形成 M-THBAQS-CTMAB三元络合物,ε_(315nm)~(Zr)=3. 27×10~4,ε_(515nm)~(HI)=3.8×10~4,适量H_2O_2使锆络合物吸光度显著降低,据此实现了锆铪的同时测定.本法简便快速、适用范围为0～30μgZr/25 mL,0～25μg Hf/25 mL,且X_(Zr)+X_(Hf）<35μg/25 mL.     

钴(Ⅱ)-甲基百里香酚蓝络合剂-亚硝酸根络合吸附波的研究及应用

在pH 8.5、0.04 mol/L NH3*H2O-NH4Cl缓冲溶液中,钴-甲基百里香酚蓝络合剂(MTB)在NaNO2存在下,于-1.23 V(vs.SCE)产生一尖锐、灵敏的二次导数极谱波,峰电流与钴(Ⅱ)浓度在5.0×10-8～2.0×10-6 mol/L范围内呈线性关系;检出限为1.0×10-8 mol/L.研究了该波的性质及电极反应机理,证明该波为络合吸附波.峰电流由中心离子钴(Ⅱ)还原产生.络合物在汞电极上的饱和吸附量为5.18×10-9 mol/cm2,符合Frumkin等温式.测得吸附系数β=6.86×105,自由能ΔGθ=33.30 kJ/mol;电子转移数n=2.不可逆吸附的转移系数α=0.58,反应速率常数ks=2.26/s.方法用于VB12和模拟样中痕量钴的测定,结果满意.     

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.     

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.     

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.     

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.     

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^-。