12种嘌呤类化合物的滤纸基质室温燐光法研究

较为详细地研究了１２种嘌呤类化合物以滤纸为基质的室温燐光（ＲＴＰ）光谱特性与分子结构的关系，以及重原子效应和酸度效应对ＲＴＰ的影响。     

Thermal and Kinetic Studies on the Stability of Some Ureido-Sulfonamide Derivatives

The kinetic and thermal behaviour of the following compounds: R-HN-CO-NH-(CH₂)_n-C₆H₄-SO₂NH₂ where R=3,4-dichlorophenyl, phenyl, cyclohexyl; n=0, 1, 2 were studied by TG and DTA techniques. The compounds decompose in many steps; the last one corresponding to the burning of H₂N–S–C₆H₄–C₆H₄–S–NH₂ occurs with comparable reaction rates. This revised version was published online in August 2006 with corrections to the Cover Date.     

Synthesis and Thermal Study of Magnesium Complexes with 8-hydroxyquinolinate Derivatives

Magnesium ion was reacted with 5,7-dibromo-, 5,7-dichloro-, 7-iodo-and 5-chloro-7-iodo-8-hydroxyquinoline, in acetone/ammonium hydroxide medium under constant stirring to obtain (I) Mg[(C₉H₄ONBr₂)₂]·2H₂O; (II) Mg[(C₉H₄ONCl₂)₂]·3H₂O; (III) Mg[(C₉H₅ONI)₂]·2H₂O and (IV)Mg[(C₉H₄ONICl)₂]·2.5H₂O complexes. The compounds were characterized by elemental analysis, IR spectra, ICP, TG-DTA and DSC. Through thermal decomposition residues were obtained and characterized, by X-ray diffractometry, as a mixture of hexagonal MgBr₂ and cubic MgO to the (I) compound at 850°C; cubic MgO to the (II), (III) and (IV) compounds at750, 800 and 700°C, respectively. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermal properties of zinc butyrate complex compounds

The new zinc(II) complexes of general formula Zn(CH₃CH₂CH₂COO)₂· nL (whereL = caffeine, nicotinamide, theobromine;n=1 or 2) were prepared and identified.Thermal properties of these compounds were investigated by thermal analysis (TG/DTG, DTA, DSC/DDSC).Gaseous products of thermal decomposition were detected by IR spectroscopy and Mass spectroscopy. Final products of thermal decomposition were determined by X-ray powder diffraction patterns.This work was supported by the Slovak Ministry of Education Grant No. 1/3230/96. This financial support is gratefully acknowledged.     

鬼臼毒素及其衍生物热分解反应的动力学研究

The thermal behavior and thermal decomposition kinetic parameters of podophyllotoxin （1） and 4 derivatives, picropodophyllin （2）, deoxypodophyllotoxin （3）, fl-apopicropodophyllin （4）, podophyllotoxone （5） in a temperature-programmed mode have been investigated by means of DSC and TG-DTG. The kinetic model functions in differential and integral forms of the thermal decomposition reactions mentioned above for first stage were established. The kinetic parameters of the apparent activation energy Ea and per-exponential factor A were obtained from analy- sis of the TG-DTG curves by integral and differential methods. The most probable kinetic model function of the decomposition reaction in differential form was （1- a）^2 for compounds 1-3,2/3·a^-1/2 for compound 4 and 1/2（1-a）·[-In（1-a）]^-1 for compound 5. The values of Ea indicated that the reactivity of compounds 1-5was increased in the order： 5〈4〈2〈1〈3. The values of the entropy of activation △S^≠, enthalpy of activation △H^≠ and free energy of activation △G^≠ of the reactions were estimated. The values of △G^≠ indicated that the thermal stability of compounds 1-3 with the samef（a） was increased in the order： 2〈3〈1.     

可可碱、咖啡因、茶碱的滤纸基质室温燐光测定

以快速定量滤纸为基质 ,用KI NaAc为重原子微扰剂 ,建立了测定痕量可可碱、咖啡因、茶碱的滤纸基质室温磷光 (PS RTP)分析法。该法取样量少 ,线性范围宽 ,可可碱、咖啡因、茶碱的线性范围分别为 14 4～5 76 ;5 .4 4～ 6 99;7.2 1～ 36 0ng/斑点 ;检出限分别为 1 14、0 78、1 80ng/斑点。该方法用于巧克力中可可碱、茶叶中咖啡因、氨茶碱药片中茶碱的测定 ,操作简便快速 ,选择性好。标准回收率在 92 8%～ 10 6 %之间 ;相对标准偏差RSD <5 %     

Thermal Decomposition of Fullerene Derivatives A Synthesis Method of New Fullerene Based Molecules

The thermal decomposition of methano-fullerene derivatives such as ethoxycarbonyl methano[60] fullerene and various isomers of bis-(ethoxycarbonyl methano)[60] fullerene leads to new fullerene derivatives, which have been preliminary characterized. The analysis of separated species was performed by UV-VIS, IR, H- and C-NMR, STM, FAB, LDI and MALDI-TOF MS spectroscopy. One of the isolated phases is a C₁₂₂ molecule with a dumbbell-like structure. This revised version was published online in July 2006 with corrections to the Cover Date.     

生物碱样品中有效成分的CZE法分离与测定

建立了一种简单的同时分离测定生物碱样品中咖啡因、可可碱和茶碱3种有效成分的区带毛细管电泳法。采用未涂层石英毛细管(75μm i.d.×60 cm,有效长度50 cm),以20 mmol.L-1硼砂-4 mmol.L-1β-CD(pH 9.0)为运行缓冲液,压力(0.5 psi)进样5 s,运行电压16 kV,检测波长273 nm,温度25℃。在优化的实验条件下,3种生物碱的电泳谱图峰面积与其质量浓度在0.036～0.288 g.L-1呈良好线性关系(r≥0.998 4);方法的精密度、重复性和稳定性良好,其峰面积的RSD均不大于3.2%,其检出限均不大于2.7mg.L-1;加标回收率为97%～104%。该方法简单、快速、试剂消耗少,可用于生物碱样品中咖啡因、可可碱和茶碱的分离与测定。     

Thermal Decomposition of Axinite

The thermal decomposition of axinite was studied by means of thermal, FTIR and X-ray methods. Dehydroxylation takes place in a rather narrow temperature range, the maximum of the corresponding peak being at ca. 900°C. The decomposition products are anorthite, rankinite and probably also small amounts of other, partly amorphous phases. This revised version was published online in July 2006 with corrections to the Cover Date.     

Kinetics of Thermal Decomposition of Dolomite

The thermal decomposition reactions of calcitic dolomite were investigated. Simultaneous TG/DTG/DTA were applied under non-isothermal conditions. From the recorded curves, the activation energies, pre-exponential factors and thermodynamic parameters of activation were calculated for the two thermal decomposition steps. This revised version was published online in August 2006 with corrections to the Cover Date.     

Thermal Decomposition of Some Chemical Compounds Used As Food Preservatives and Kinetic Parameters of This Process

Thermal decomposition processes of selected chemicals used as food preservatives such as sodium formate, sodium propionate, sodium nitrates(V and III) and sodium sulphate(IV) were examined by the derivatographic method. Based on the curves obtained, the number of decomposition stages and characteristic temperatures of these compounds have been found. Mass decrements calculated from TG curves ranged from 28.9% for sodium formate to 77.8% for sodium nitrate(V), while sodium sulphate showed a mass increment of 5.6%. Kinetic parameters such as activation energy (E _a ), frequency factor (A ) and reaction order (n ) were calculated from TG, DTG and T curves. Sodium formate shows the highest values of E _a and A which amount to 171.7 kJ mol^–1 and 5.8⋅10¹⁴ s^–1 , respectively, while the lowest ones, E _a =28.2 kJ mol^–1 and A =3.65⋅10² s^–1 belong to sodium nitrate(V). This revised version was published online in August 2006 with corrections to the Cover Date.     

高效液相色谱法对牦牛血浆与尿中嘌呤衍生物及肌酐含量的测定

建立了牦牛血浆及尿中的嘌呤衍生物及肌酐含量测定的HPLC/UVD方法.在室温条件下,以乙酸铵为流动相,分别以Lichrospher RP-C18 Merck(4.6×250 mm,5 μm i.d.)和5C18-AR-Ⅲ Waters(4.6×250 mm)为色谱柱,检测波长220 nm,流速1 mL/min,对尿囊素、尿酸、肌酐、黄嘌呤和次黄嘌呤进行了检测.方法检出限(LOD)为0.2 ~0.4 μmol/L,血样和尿样的加标回收率分别为81% ~103%、83% ~104%.     

丙硫异烟胺的热稳定性及其热分解动力学

通过热重法研究了抗结核药物丙硫异烟胺的热稳定性, 计算了该药物的动力学参数并建立了热分解动力学方程. 用Kissinger和Ozawa-Flynn-Wall两种方法计算该药物热分解过程的活化能Ea=54.65 kJ·mol-1. 用Malek法推断该药物的动力学机理函数及指前因子A, 其结果分别为f(α)=α0.391(1-α)0.145, lnA=13.12. 此外, 用差热法测定该物质的熔点、摩尔熔化焓和摩尔熔化熵, 分别是414.09 K、23.21 kJ·mol-1和56.06 J·mol-1·K-1.     

Mechanism of Thermal Decomposition of Barium Benzoate

Barium benzoate was synthesized in a hydrothermal reaction. The complex was characterized by elemental analysis, IR spectroscopy and X-ray powder diffraction. It was monoclinic and had a layered structure. The mechanism of thermal decomposition of the barium benzoate was studied by using TG, DTA, IR and gas chromatography-mass spectrometry. In a nitrogen atmosphere, the barium benzoate decomposed to form BaCO₃ and organic compounds: mainly benzophenone, triphenylmethane, etc.This revised version was published online in November 2005 with corrections to the Cover Date.     

Influence of the Heating Rate in the Thermal Decomposition of HMX

This work refers to a study of the thermal decomposition of octahydro-1,3,5,7-tetranitro-1,3,5,7 tetrazocine (HMX) by differential scanning calorimetry (DSC) in non-isothermal conditions, with heating rates from1 to 25°C min⁻¹. The influence of the heating rate, the particle and the sample size were verified. The activation energy was calculated using the peak temperature shift method, proposed by Ozawa and a significant variation in the results was observed according to the range of the used heating rates. As the heating rate was increased, different conversions and self-heating effects were observed at the respective DSC peaks, indicating that the use of this method was inadequate and it may lead to incorrect results, which, in turn, could explain the wide range of activation energy values published in literature. At lower heating rates HMX decomposition occurs on the solid state and at higher ones decomposition occurs after melting practically at the same temperature, which does not depend on the heating rate. This revised version was published online in July 2006 with corrections to the Cover Date.     

柚皮苷的热稳定性及其热分析动力学研究

用TG-DTG/DTA方法研究了柚皮苷的热降解过程及热分析动力学. 热重分析结果表明该物质的失重过程分两步进行. 第一步为结晶水脱出, 其温度范围为343～545 K, 第二步为其分子骨架大规模降解, 其温度范围在545～857 K. 差热分析结果表明, 该物质的熔化温度为439.2 K. 使用Friedman和Ozawa-Flynn-Wall两种方法分别计算出该物质降解过程的活化能. 采用多步线性回归方法, 并参考常用的15种热解机理函数, 确定了柚皮苷热解过程最佳动力学模型为Fn-F2-F1.     

Thermal study of zinc(II) salicylate complex compounds with bioactive ligands

Five new complex compounds of general formula Zn(Hsal)_2·L₂·nH₂O (where Hsal=OHC₆H₄COO^-, L=thiourea (tu), nicotinamide (nam), caffeine (caf), theobromine (tbr), n=2-4), were prepared and characterized by chemical analysis, IR spectroscopy and studied by methods of thermal analysis (TG/DTG, DTA). It was found that the thermal decomposition of hydrated compounds starts with the release of water molecules. During the thermal decomposition of anhydrous compounds the release of organic ligands take place followed by the decomposition of salicylate anion. Zinc oxide was found as the final product of the thermal decomposition heated up to 800°C. RTG powder diffraction method, IR spectra and chemical analysis were used for the determination of products of the thermal decomposition. This revised version was published online in August 2006 with corrections to the Cover Date.     

丹酚酸B的热稳定性及其热分解动力学研究

用TG-DTG 方法研究了丹参的有效成分丹酚酸B 的热降解过程. 热重分析结果表明该物质的失重过程分两步进行. 笫一步为脱去吸附水, 其温度范围为305～373 K, 第二步为丹酚酸B 分子骨架大规模降解, 其温度范围在413～864 K. 用Friedman 和Ozawa-Flynn-Wall 两种方法分别计算出该药物降解过程中的三个阶段的活化能, 采用多步线性回归方法, 并参考常用的15 种热解机理函数, 确定了丹酚酸B 热降解过程最佳动力学模型为Fn-F2-F1.     

4-氨基吡啶催化6-烷氧基取代嘌呤衍生物的合成

以6-氯嘌呤为底物,4-氨基吡啶为催化剂,甲醇为溶剂合成了6-烷氧基取代嘌呤化合物。 当反应条件为n(6-氯嘌呤)∶n(4-氨基吡啶)∶n(三乙胺)=10∶1∶4,回流反应5~7 h时,6-烷氧基嘌呤化合物的收率大于85%。 研究表明,体系中6-氯嘌呤、4-氨基吡啶和三乙胺的相对量对反应有很大影响,用4-氨基吡啶-三乙胺混合催化剂体系催化效果更好。     

Kinetic Modeling of the Decomposition of Carbon Tetrachloride in Thermal Plasma

Decomposition of carbon tetrachloride in a RF thermal plasma reactor was investigated in argon atmosphere. The net conversion of CCl₄ and the main products of its decomposition were determined from the mass spectrometric analysis of outlet gases. Flow and temperature profiles in the reactor were calculated and concentration profiles of the species along the axis of the reactor were estimated using a newly developed chemical kinetic mechanism, containing 12 species and 34 reaction steps. The simulations indicated that all carbon tetrachloride decomposed within a few microseconds. However, CCl₄ was partly recombined from its decomposition products. The calculations predicted 70\% net conversion of CCl₄, which was close to the experimentally determined value of 60\%. A thermodynamic equilibrium model also simulated the decomposition. Results of the kinetic and thermodynamic simulations agreed well above 2000 K. However, below 2000 K the thermodynamic equilibrium model gave wrong predictions. Therefore, application of detailed kinetic mechanisms is recommended for modeling CCl₄ decomposition under thermal plasma conditions.