Propane oxidation over Pd/LaFe0.8Co0.2O3 catalyst

Pd/LaFe_0.8Co_0.2O₃ was found to be more active than the Pd/Al₂O₃ catalyst in propane oxidation. Activity and the oxidation state of palladium were strongly affected by the redox ratio (S) of reactants. Higher propane conversion could be obtained under rich conditions at higher temperatures, contributing to steam reforming. The presence of excess steam would bring about inhibition and oscillation.     

Pyranoxanthones from Calophyllum Inophyllum

Phytochemical investigation of the stem bark of Calophyllum inophyllum resulted in the isolation of a new dipyrenoxanthone, calophinone ( 1 ), together with four related xanthones ( 2–5 ). Identification of the isolated compounds was achieved through intensive studies of their spectral data, especially 2D NMR.     

电场作用下苏氨酸的电流特性研究

制备了以液态苏氨酸为沟道材料的四端有机场效应晶体管,观测了其随着栅极电压的不同呈现出源漏两极之间不同的电学特异现象;还观测了苏氨酸在外电场作用下,阻抗随着源漏之间电压频率变化的关系,提出一个极性液体模型解释了其导电机理。     

表面包覆改性对纳米CeO2分散性的影响

了改善纳米CeO2在Zn-Al类共晶合金中的分散性,采用超声液相包覆法对纳米CeO2进行表面活性剂表面包覆改性,并用AES测定了包覆层的厚度,用TEM研究了CeO2的团聚状况,用TGA分析了有机物包覆层的炭化温度范围,最后用FE-SEM观察了CeO2在复合材料中的分散情况。结果表明,包覆在纳米CeO2表面的厚度约为20 nm的表面活性剂层提高了微粒的分散性,而且该包覆层在495℃时已经炭化。热力学计算的结果也表明,炭化层能与氧化膜反应,该反应提高了CeO2与基体间的润湿性,并使其均匀分布在基体合金中。     

AM1法研究乙烯与环己－1，3－二烯热加成反应

用ＡＭ１方法（采用非限制的Ｈａｒｔｒｅｅ－ＦｏｃｋＵＨＦ计算）研究乙烯与环己－１，３－二烯的热Ｄｉｅｌｓ－Ａｌｄｅｒ反应。结果表明反应是放热的且存在两条竞争的路径；协同反应的活化能以及双自由反应速度控制步骤的活化能分别为１１２．６６７ｋＪ／ｍｏｌ和７８．４０６ｋＪ／ｍｏｌ。     

粘质沙雷氏菌脂肪酶的固定化及催化拆分反式3-(4’-甲氧苯基)缩水甘油酸甲酯

 对粘质沙雷氏菌脂肪酶进行了固定化研究,确定硅藻土和环氧树脂Eupergit C是较好的固定化载体. 固定化后酶的热稳定性、 pH稳定性及储存稳定性均明显提高. 以Eupergit C共价固定的脂肪酶,其操作稳定性比硅藻土吸附酶好,重复使用10批次后,剩余酶活力还有50%左右,戊二醛交联对Eupergit C固定化酶稳定性的提高没有明显效果,而硅藻土吸附酶经戊二醛交联后稳定性有所提高,经5批次反应后剩余酶活力还有50%. 使用交联后的硅藻土固定化酶(1 g, 200 U), 在两相搅拌反应器(工作体积200 ml, 甲苯∶水体积比=1)中对地尔硫卓手性前体(±)-反式3-(4’-甲氧苯基)缩水甘油酸甲酯((±)-MPGM)(有机相浓度为0.5 mol/L)进行了催化拆分,经5批次反应后,共得纯(2R,3S)-(-)-MPGM 18.6 g, 产品光学纯度(对映体过量)>99%, 总收率为37.2%.     

有机硅耐磨透明涂层的固化分析

ＦＴＩＲ、ＴＧ、ＴＢＡ等对有机硅耐磨涂料（有机硅溶胶）的热固化过程研究表明有机硅胶体中缔合羟基间的脱水缩合速率很高；羟基脱水程度与固化温度有关，温度越高，达平衡时羟基的浓度越低，在１０５～１３０℃间羟基的浓度变化最大，加入适当的固化剂，对羟基的脱水交联有促进作用，在较高的固化温度下，反应体系中出现了环氧环异构化产生的酮羰基的吸收峰     

测接触角法确定偶联剂的最佳用量

偶联剂是一类能在无机填料和聚合物基材之间形成“分子桥”、改善两者之间相容性或提高两者之间相互作用能力的化合物。将经偶联剂改性的无机填料填充到聚合物中可以制得成本低、性能好的复合材料。由于偶联剂用量多少将对复合材料的性能产生较大影响,因此建立一种准确、简便地确定偶联剂最佳用量的方法有着十分重要的理论和实际应用意义。     

新马兜铃内酯的晶体结构

从绵毛马兜铃的根茎中分离出一种新的倍半萜内酯, 它的分子式由高分辨质谱数据确定为C~1~5H~2~0O~2, 它的结构用单晶X射线衍射法测定, 晶体属三斜晶系, 空间群为P1, a=0.6275(3)nm, b=0.8057(4)nm, c=1.3622(6)nm; α=88.78(4)°,β=91.44(4)°, γ=105.20(4)°; Z=2.3107。     

Modified modeling of the effect of pH and viscosity on the mass transfer in hydrophobic hollow fiber membrane contactors

This paper studied the effect of pH and the viscosity of feed solution on the mass transfer in two different specifications of hydrophobic hollow fiber membrane contactors. Experimental results showed that the pH of the feed had a significant effect on the rate of mass transfer, the flux and the removal efficiency of easily ionized volatile compounds (VCs), such as ammonia. In unbuffered feed solutions, both the resistance of membrane and the resistance of feed side were affected by the pH of feed and both of them had contributions to the overall mass transfer. A model, , was proposed to predict the effect of pH and gave good agreement with the experimental data for the two contactors. The relationship between viscosities and the mass transfer coefficient could be described by . Based on our experiments, the change of the viscosities in the concentration range of ammonia from 50 to 10,000 mg l⁻¹ caused about 3–4% variation of the mass transfer coefficients. Moreover, it may be more suitable to use the equilibrium concentrations of volatile species instead of the total concentrations of VCs to estimate mass transfer coefficients, removal efficiency and flux. Experimental results also revealed that the choice of the pH of feed might be one of the most crucial factors for removing easily ionized VCs, such as ammonia, from water and wastewater.