甲酰胺在乙二醇-水混合溶剂中的稀释焓

酰胺是肽的基本结构单元, 而且在蛋白质的二级结构中与酰胺联系的氢键对蛋白质的稳定起着十分重要的作用. 作为蛋白质模型化合物热力学性质研究的一部分, 报道了甲酰胺在乙二醇水溶液中的稀释焓.      

苯并三氮唑及其羧酸酯衍生物对铜缓蚀机理的分子动力学模拟研究

用分子动力学(MD)方法, 模拟计算了5种铜缓蚀剂[苯并三氮唑(BTA)、苯并三氮唑-5-羧酸甲酯(MBTC)、苯并三氮唑-5-羧酸丁酯(BBTC)、苯并三氮唑-5-羧酸己酯(HBTC)、苯并三氮唑-5-羧酸辛酯(OBTC)]与Cu₂O晶体的相互作用. 结果发现, 中性条件下缓蚀剂分子与Cu₂O晶体的结合能均大于酸性条件下的数值, 但两种条件下结合能的大小排序均为OBTC＞HBTC＞BBTC＞MBTC＞BTA. 对体系各种相互作用以及对关联函数g(r)的分析表明, 体系结合能主要由库仑作用提供, Cu₂O晶体中的Cu原子与缓蚀剂分子中的N原子之间形成了配位键. 在与Cu₂O(001)晶面结合过程中, BTA及其衍生物分子发生了扭曲变形, 但形变能远小于体系的非键相互作用能.     

（H2O）^＋n（n=1,2）的几何结构优化和振动光谱分析

采用Ｈａｒｔｒｅｅ－Ｆｏｃｋ和ＭＰ２方法在多种水平下优化了（Ｈ２Ｏ）＾＋ｎ（ｎ ＝１，２）的几何结构，并进行了振动光谱分析。结果表明：对（Ｈ２Ｏ）＾＋采用ＭＰ２／６－３１１＋＋Ｇ（ｄ，ｐ）可得出最满意的结论。     

壳聚糖浓溶液流变性质研究──分子量的依赖性

series of chitosan samlpes with 91% deacetylation but different molecular weight were obtained by varying the time of chitosan solution in acetic acid aqueous solution at 70℃.The viscosities and flow behavior of the concentrated solutions of chitosan were investigated in 10% (vol%) formic acid aqueous solution after the solutions were prepared for two days by using RPX-705 Rheopexy Analyzer.For each chitosan sample,at the concentration of 3.5 g/100ml,the log (ηr/η0)versus lgγη0,M curves superimpose each other within the same rheogramme. Then the relationship between log nr and lgM was studied under different shear rates.For the highest M sample, the experimental data deviate from the straight lines greatly. This was because the chitosan chain degradated in acid solution during dissolving. The molecular weights were measured in acid solution after two days of dissolving, they were right on their own straight lines. However,no obvious degradation was observed after two days in the same solution for the other lower M chitosan sam-ples. In addition, the plot of nr against M was not a straight line,probaly due to particular interaction of chitosan.     

探究Cu/ZnO相互作用对CO2加氢制甲醇反应性能的影响

Using renewable green hydrogen and carbon dioxide (CO₂) to produce methanol is one of the fundamental ways to reduce CO₂ emissions in the future, and research and development related to catalysts for efficient and stable methanol synthesis is one of the key factors in determining the entire synthesis process. Metal nanoparticles stabilized on a support are frequently employed to catalyze the methanol synthesis reaction. Metal-support interactions (MSIs) in these supported catalysts can play a significant role in catalysis. Tuning the MSI is an effective strategy to modulate the activity, selectivity, and stability of heterogeneous catalysts. Numerous studies have been conducted on this topic; however, a systematic understanding of the role of various strengths of MSI is lacking. Herein, three Cu/ZnO-SiO₂ catalysts with different strengths of MSI, namely, normal precipitation Cu/ZnO-SiO₂ (Nor-CZS), co-precipitation Cu/ZnO-SiO₂ (Co-CZS), and reverse precipitation Cu/ZnO-SiO₂ (Re-CZS), were successfully prepared to determine the role of such interactions in the hydrogenation of CO₂ to methanol. The results of temperature-programmed reduction (H₂-TPR) and X-ray photoelectron spectroscopy (XPS) characterization illustrated that the MSI of the catalysts was considerably affected by the precipitation sequence. Fourier transform infrared reflection spectroscopy (FT-IR) results indicated that the Cu species existed as CuO in all cases and that copper phyllosilicate was absent (except for strong Cu-SiO₂ interaction). Transmission electron microscopy (TEM), X-ray diffraction (XRD), and N₂O chemical titration results revealed that strong interactions between the Cu and Zn species would promote the dispersion of Cu species, thereby leading to a higher CO₂ conversion rate and improved catalytic stability. As expected, the Re-CZS catalyst exhibited the highest activity with 12.4% CO₂ conversion, followed by the Co-CZS catalyst (12.1%), and the Nor-CZS catalyst (9.8%). After the same reaction time, the normalized CO₂ conversion of the three catalysts decreased in the following order: Re-CZS (75%) > Co-CZS (70%) > Nor-CZS (65%). Notably, the methanol selectivity of the Re-CZS catalyst was found to level off after a prolonged period, in contrast to that of Co-CZS and Nor-CZS. Investigation of the structural evolution of the catalyst with time on stream revealed that the high methanol selectivity of the catalyst was caused by the reconstruction of the catalyst, which was induced by the strong MSI between the Cu and Zn species, and the migration of ZnO onto Cu species, which caused an enlargement of the Cu/ZnO interface. This work offers an alternative strategy for the rational and optimized design of efficient catalysts.     

超支化双亲水性嵌段共聚物对CaCO3结晶影响的研究

采用合成的聚乙二醇-超支化聚酯(PEG-hb-DMPA)的线性-超支化杂化二嵌段共聚物, 探讨了羧端基树状功能化的杂化嵌段共聚物对CaCO₃结晶的影响，并用FTIR、XRD、SEM等对产物进行了表征。结果表明，羧端基的双亲水性嵌段共聚物对CaCO₃结晶形貌乃至晶型均具有显著调控作用，比较高的浓度(1.67 g·L^-1, >10 min)或较低浓度作用较长时间(0.33 g·L^-1, 24 h)均得到了呈较均匀球粒形态的球霰石CaCO₃结晶。     

一步法合成N-1,3-二羟基丙烷-2-基烷基乙酰胺

以5-氨基烷基-2,2-二甲基-1,3-二噁烷为起始原料, 乙酸酐为酰化剂, 一步法选择性地合成氨基二醇类氨基乙酰化产物N-1,3-二羟基丙烷-2-基烷基乙酰胺. 该方法操作简便, 收率高. 所合成的4个新化合物的结构均经FTIR, ¹H NMR, ¹³C NMR及HRMS确证. N-3-(1,3-二羟基丙烷-2-基)丙基乙酰胺(1a)作为关键的中间体, 可以用于HIV-1 Tat/ PCAF BRD抑制剂4的合成.     

纳米级碳导电剂的种类对licoo2电化学性能的影响

碳纳米管;锂离子电池;正极;倍率容量;导电剂     

5-氟尿嘧啶-1-乙酸合铜(Ⅱ)的合成及其与DNA的作用

The 5-fluorouracil-1-acetic acid (5FuAA) and its Cu(Ⅱ) complex (5FuAACu) were synthesized and the date for the crystal complex was obtained. The interaction of 5-fluorouracil-1-acetic acid (5FuAA) and its Cu(Ⅱ) complex (5FuAACu) with DNA was also investigated by using spectral, viscometric, electrochemical and agarose gel electrophoresis methods. The results of interaction with DNA suggest that both 5FuAA and 5FuAACu can bind to DNA in a static electricity attraction mode. But the attraction of 5FuAACu is greater than that of 5FuAA.     

HNCS与C_2H(X~2Π)反应微观动力学的理论研究

用量子化学密度泛函理论的UB3LYP/6-311 G鄢鄢方法和高级电子相关的UQCISD(T)/6-311 G鄢鄢方法研究了异硫氰酸(HNCS)与乙炔基自由基(C2H(X2Π))反应的微观机理.采用双水平直接动力学方法IVTST-M,获取反应的势能面信息,应用正则变分过渡态理论并考虑小曲率隧道效应,计算了在250～2500K温度范围内反应的速率常数.研究结果表明,HNCS与C2H(X2Π)反应为多通道、多步骤的复杂反应,共存在三个可能的反应通道,主反应通道为通过分子间H原子迁移,生成主要产物NCS C2H2.反应速率常数随温度升高而增大,表现为正温度效应.速率常数计算中变分效果很小.在低温区隧道效应对反应速率的贡献较大,反应为放热反应.