内标法测定卡波姆中乙酸乙酯和环己烷的残留量

建立了卡波姆中环己烷和乙酸乙酯残留量的内标GC测定方法.色谱柱:DB-WAX,30 m×0.32 mm×0.25μm;柱温:50℃维持3 min,然后以5℃/min的速度升至120℃,维持15 min.进样口温度:250℃;FID检测器,温度:250℃;进样量:1μL.空白溶液色谱图中,丁酮、环己烷、乙酸乙酯峰处无干扰.环己烷与相邻峰的分离度约为6;乙酸乙酯与相邻峰的分离度约为2.5.环己烷和乙酸乙酯进样量在0.2～1.2 ng范围内线性关系良好(r=0.999 2和0.999 8).环己烷平均回收率为101.4%,RSD=1.3%(n=6),乙酸乙酯平均回收率为100.6%,RSD=1.1%(n=6).该方法操作简便,灵敏度高,分离度好,结果准确,重复性也比较好,适合卡波姆中乙酸乙酯和环己烷的含量测定.     

甲基环己烷在9∽15.5 eV能量区的真空紫外光电离研究

利用具有同步辐射源的反射式飞行时间质谱仪，研究甲基环己烷的真空紫外光电离和光解离. 观测到母体离子C₇H₁₄⁺和碎片离子C₇H₁₃⁺，C₆H₁₁⁺，C₆H₁₀⁺，C₅H₁₀⁺，C₅H₉⁺，C₄H₈⁺，C₄H₇⁺和C₃H₅⁺的光电离效率曲线. 测定甲基环己烷的电离能为9.80±0.03 eV，通过光电离效率曲线确定其碎片离子的出现势. 在B3LYP/6-31G(d)水平上对过渡态、中间体和产物离子的优化结构进行表征，并使用G3B3方法计算其能量. 提出主要碎片离子的形成通道. 分子内氢迁移和碳开环是甲基环己烷裂解途径中最重要的过程.     

乳酸促进的仲钼酸铵催化氧化环己烷过程

环己烷的催化氧化是重要的工业反应之一,为了寻找更高效廉价的催化剂,研究了仲钼酸铵(APM)对环己烷氧化的催化活性,并着重探讨了酸助剂的种类及添加量对APM催化活性的影响。 与硝酸相比,乳酸对环己醇转化为环己酮的过程促进作用更强,且使反应物的有效利用率更高,并由此将APM对目标产物的总TON(turn over number)值由124提高到161。     

合成黑索今中副产物3, 5-二硝基-1-氧-3, 5-二氮杂环己烷的晶体结构及热分解动力学

A new cyclic byproduct was formed during hexahydro-1, 3, 5-trinitro-1, 3, 5-triazine (RDX) preparation by direct nitration. Silicone column chromatography with acetone and dichloromethane in various ratios as the eluent was used to separate 3, 5-dinitro-1-oxygen-3, 5-diazacyclohexane from the product mixture. A single crystal of 3, 5-dinitro-1-oxygen-3, 5-diazacyclohexane was grown from acetone, and characterized using elemental analysis, Fourier-transform infrared (FTIR) spectroscopy, ¹H nuclear magnetic resonance (NMR) spectroscopy, and mass spectrometry (MS). Its structure was determined using an X-ray single-crystal diffractometer. The results indicate that the crystal molecular weight is 178.12. It belongs to the monoclinic system with the space group P121/n1, a = 0.58128(13) nm, b = 1.72389(14) nm, c = 0.71072(6) nm, β = 112.056°, V = 0.66006(16) nm³, Z = 4, D_C= 1.792 g·cm^-3, μ = 0.17 mm^-1, and F(000) = 368.0; the final deviation factor R is 0.0397. Differential scanning calorimetrythermogravimetry (DSC-TG) was used to investigate the thermal behavior of the title compound. Sharp peaks were observed at 383.15 K (melting) and 519.05 K (decomposition). The kinetic parameters were obtained using the Kissinger and Flynn-Wall-Ozawa methods and the TG data at different heating rates. The Coats-Redfern method was used to study the thermal decomposition mechanism of 3, 5-dinitro-1-oxygen-3, 5-diazacyclohexane. The results show that the title compound is a low-melting-point compound with good stability; its apparent activation energy and pre-exponential factor, calculated using the Kissinger equation, are 212.32 kJ·mol^-1 and 6.20×10²⁰ s^-1, respectively. The apparent activation energy, calculated using the Flynn-Wall-Ozawa equation, is 210.39 kJ·mol^-1. G(α) = (1-α)^-1-1 (n = 2) obtained using Coats-Redfern method is regarded as the most appropriate thermal decomposition kinetic equation.     

气相色谱法分离正己烷和环己烷的实验设计与教学探索

The experiment of separating low toxic n-hexane and cyclohexane by traditional gas chromatography was improved with orthogonal experimental design. The effect of sample quantity, vaporization chamber temperature, detector temperature, column temperature, line velocity and separability of the split ratio were examined. Through the experiment, students could understand the use and maintenance of gas chromatography instruments. At the same time, they could understand separability and column efficiency of chromatography.     

Study on the Interaction between a Kind of Thieno[2,3-d] Pyrimidin-4(3H)-one and Bovine Serum Albumin by Fluorescence Spectrometric Method

用荧光光谱法研究了在生理条件下,3-对氯苯基-2-(4-叔丁基苯氧基)-3'-氧环己烷并噻吩并[2,3-d]嘧啶-4(3H)-酮(PTP)与牛血清白蛋白(BSA)的相互作用.实验表明,PTP主要以静态猝灭方式使BSA荧光强度显著降低.计算了不同温度下二者的结合常数和结合位点数,并根据热力学参数确定了PTP与BSA之间的作用力主要为氢键或范德华力.根据F(o)rster非辐射能量转移机理,测定了PTP与BSA相互结合时的作用距离,并用同步荧光技术讨论了其衍生物对BSA构象的影响.     

助剂形态对Pt/γ-A12O3催化剂抗积炭性能的影响

采用CO和H2脉冲吸附、程序升温还原、NH3程序升温脱附及X射线衍射等手段对各金属氧化物改性的Pt/Al2O3催化剂进行了表征,研究了助剂形态对Pt/Al2O3催化剂在非临氢条件下催化环己烷脱氢反应性能的影响.结果表明,催化剂稳定性从高到低依次为Zr-Pt/Al2O3＞ Ca-Pt/Al2O3＞ Ce-Pt/Al2O3...     

快速扫描量热法研究聚对苯二甲酸-1,4-环己烷二甲醇酯的结晶和熔融行为

采用快速扫描量热法(FSC)结合传统的差示扫描量热仪(DSC)考察了聚对苯二甲酸-1,4-环己烷二甲醇酯(PCT)聚酯在接近玻璃化转变(T_g)和熔融温度(T_m)范围(100~270 ℃)的结晶和熔融行为。 较大过冷度时PCT聚酯结晶较快,FSC有效地抑制降温过程结晶的发生,而较低过冷度下传统DSC可以避免样品降解对实验结果的影响,二者的结合能很好地对PCT聚酯结晶动力学进行测量,实验结果表明在175 ℃时结晶速率最快。 并且利用Flash DSC对等温结晶温度下形成的片晶熔点进行加热速率的相关测量,在熔融动力学建模的基础上进行校准,以确定零加热速率下片晶的熔点。 Hoffman-Weeks方程中T_m与结晶温度(T_c)的线性关系与T_c=T_m的交点给出了PCT晶体的平衡熔融温度$T_m^o$为315 ℃。     

几种环状分子的拉曼光谱研究

通过实际检测获得了环己烷、四氢呋喃、1,4-二氧己环（二恶烷）几种环状分子的拉曼光谱。并应用密度泛函理论对几种环状分子的拉曼振动峰进行了详细的分析。研究结果表明：几种环状分子最强拉曼振动峰均由环呼吸运动引起,但它们的波数值差异较大,可以作为鉴定此类分子的判断依据。应用拉曼光谱检测技术可以对此类有毒物质进行快速的鉴定与分析。     

一种快速调整双液系溶液的方法

物理化学实验中的双液系相图绘制实验需要测定一系列浓度的环己烷-乙醇溶液,实验结束后,被测溶液的浓度均发生较大变化。提出一个简便调整这些溶液的方法,并对该方法进行了验证。结果表明该方法可快速方便地将实验后的溶液浓度调整为实验前起始状态,以便于溶液的循环使用,既可避免环境污染,也减少了试剂的浪费。