超细Ni-Cu-Co-La的制备及其催化乙腈加氢性能

以水合肼和硼氢化钾为共还原剂制备了四元合金催化剂Ni-Cu-Co-La,并将其应用于乙腈催化加氢反应.采用X射线衍射、X射线光电子能谱、透射电镜和H2程序升温脱附对催化剂进行了表征,考察了催化剂组分对乙腈选择性加氢制乙胺催化性能的影响.结果表明,Cu,Co和La的加入均不同程度地提高了催化剂的活性和选择性,在反应压力1.8 MPa,反应温度120℃,反应时间1 h的条件下,乙腈转化率和乙胺选择性分别为100%和98.24%,优于使用Raney Ni、非晶态Ni-B和Co-B合金催化剂时的结果.     

Effect of temperature on dynamic rheological behavior of discontinuous cubic liquid crystal

The dynamic rheological properties of discontinuous cubic liquid crystal, formed by nonionic surfactant C(12-14)E(12), were investigated in the discrete and continuous patterns of raising temperature. In the discrete pattern, the discontinuous cubic phase appears in two types of viscoelastic behaviors under the melting points of cubic phase: elastic gel and viscoelastic liquid. When the discontinuous cubic phase begins to melt, it has the weak polymer-like viscoelasticity. Temperature and shear frequency have completely different effects on the ratio of viscous and elastic components of samples in these three states. At low temperature, the samples dominate in elasticity and temperature and shear frequency has hardly any effect on viscoelasticity. At moderate temperature, its ratio of viscous and elastic components increases with increasing temperature and decreasing shear frequency. At the vicinity of the melting point of cubic liquid crystal, the cubic liquid crystal appears to have almost equaled viscous and elastic component; shear has obvious effect on the ratio of viscoelasticity at low frequency. The results from the continuous pattern of raising temperature are consistent with those from the discrete pattern.     

Cu-Ni-Zn三元脂肪醇胺化催化剂的研究

 长链烷基二甲基叔胺是一类重要的有机中间体,目前其主要的制备工艺是由脂肪醇和二甲胺在脱氢－加氢类催化剂的作用下进行胺化反应．改进脂肪醇胺化催化剂的主要目标是提高其选择性．对以Cu和Ni为活性组分,以碳酸钙为载体的催化剂体系中加入Zn助催化剂组分对催化剂选择性的影响进行了研究．结果发现,在相同Cu／Ni比的条件下,Zn在Cu－Ni催化剂体系中的一个主要作用是能够阻碍氧化态镍的还原,而催化剂的选择性与催化剂中镍的还原程度密切相关．     

Study on one-step catalytic amination of oleyl alcohol to unsaturated tertiary amine

The synthesis of unsaturated tertiary amine by the amination of oleyl alcohol and dimethylamine under atmospheric pressure over Cu–Ni catalysts supported on CaCO₃ was studied. The yield of tertiary amine and the retention rate of the unsaturated bond can reach 95.4 and 93.3 %, respectively. The yields of tertiary amine over different Cu/Ni ratios catalysts were close to each other, which meant that Cu/Ni ratios had no obvious influence on the production of tertiary amine, while the retention rate of the unsaturated bond over the catalyst containing only Cu was higher than the catalysts containing Cu–Ni. The major effect of the Cu element was dehydrogenation, and the ability of the hydrogenation was weak. The ability of the Ni element to break the carbon–carbon bonds and hydrogenation was strong. Therefore, the performance of the Cu catalyst was better than the conventional Cu–Ni-based catalyst for the retention of the unsaturated bond in long-chain R of the tertiary amine.     

纳米V2O5／ZnO光催化剂对壬基酚聚氧乙烯醚降解的催化活性

采用氨浸法制备了不同V2O5含量的纳米V2O5/ZnO光催化剂,并用X射线衍射、比表面积测定、透射电镜、X射线光电子能谱和漫反射紫外-可见光谱测定了催化剂的晶型、比表面积、形貌尺寸、表面组成和光谱特征.以壬基酚聚氧乙烯醚(NPE-10)为模型污染物,分别在紫外光和可见光照射下考察了光催化剂的催化活性.结果表明,随着V2O5含量的增加,V2O5/ZnO的粒径逐渐减小,比表面积逐渐增大.与纳米ZnO样品相比,V2O5/ZnO中V2p的结合能减小,而Zn2p和O1s的结合能增大,V2O5/ZnO表面的羟基氧和吸附氧含量增加.n(V)/n(Zn)=2·5%的V2O5/ZnO光催化剂样品的催化活性最高(在紫外光和可见光照射3h后,NPE-10降解率分别约为79%和62%).     

Contact electrification property controlled by amino modification of cellulose fibers

Cellulose - As a green material, cellulose is widely used in friction triboelectric nanogenerators (TENGs). However, the weak polarity of the cellulose fibers surface leads to its weak contact...     

Synthesis of glycerol carbonate from glycerol and dimethyl carbonate catalyzed by K2CO3/MgO

A series of M/MgO (M?=?CaO, KNO₃, KOH, K₂CO₃) catalysts were prepared by a dry impregnation method and used for synthesis of glycerol carbonate from glycerol and dimethyl carbonate. It was found that K₂CO₃/MgO was the most efficient catalyst, with a glycerol carbonate yield of approximately 99% under the conditions: DMC/glycerol molar ratio 2.5:1, catalyst/raw material weight ratio 1%, reaction time 2?h, and reaction temperature 80?°C. FTIR, BET, TEM, and XRD were used for characterization of the catalyst and showed that the active sites seemed to be K₂O formed on the K₂CO₃/MgO catalyst. Finally, a recycling experiment showed that the catalyst was relatively stable and could be reused up to four times, at least, by regeneration.     

Adsorption and aggregation properties of novel star-shaped gluconamide-type cationic surfactants in aqueous solution

The adsorption and aggregation behavior of novel star-shaped gluconamide-type cationic surfactants N-dodecyl-N,N-bis[(3-D-gluconylamido)propyl]-N-alkylammonium bromide (C_nDBGB, where n represents hydrocarbon chain lengths of 10, 12, and 14) has been studied on the basis of static/dynamic surface tension, conductivity, dynamic light scattering (DLS), and transmission electron microscopy (TEM) data. The static surface tension of the C_nDBGB aqueous solution measured at the critical micelle concentration (CMC) is observed to be significantly lower than that of the corresponding monomeric surfactants. The dynamic surface tension results indicate that adsorption process of above CMC is a mixed diffusion–kinetic adsorption mechanism. From the results of temperature dependent conductivity measurements, we could obtain the degree of counterion binding (β) and the thermodynamic parameters such as standard free energy (ΔG _mic ⁰ ), enthalpy (ΔH _mic ⁰ ), and entropy (ΔS _mic ⁰ ) of aggregation. With a combination of the DLS and TEM data, a size transformation of the micelles is suggested to occur with an increase in the concentration.     

基于出行距离评价城市公园绿地的可达性——以乐清市为例

公园绿地的可达性是衡量其空间布局合理性的重要指标,以出行距离来度量公园绿地的可达性是一种较为便捷和有效的方法.以乐清市城区为例,根据公园绿地的规模,设置相应的服务半径,借助ArcGIS网络分析工具,基于出行距离来评价公园绿地的可达性.与缓冲区分析和按统一服务半径(500m)进行分析对比,本方法更接近实际.     

亚精胺对溶菌酶构象及催化性能的影响

聚乙烯亚胺是典型的聚阳离子基因载体材料,但是具有一定的细胞毒性,以小分子多胺为基础制备易降解的高分子材料是降低聚乙烯亚胺类基因载体材料的细胞毒性和提高基因转染效率的重要方法。为深入了解聚乙烯亚胺类基因载体材料与生物大分子的相互作用,本文综合应用吸收光谱、共振瑞利散射、圆二色谱和荧光光谱研究典型小分子多胺化合物亚精胺与溶菌酶的相互作用及其对酶的构象、催化活性和催化动力学的影响和机理。亚精胺是两亲性分子,其氨基基团易于质子化而具有较强的静电结合和氢键形成能力,亚甲基基团则具有一定的疏水性。亚精胺较小的分子尺寸和两亲性使其可以穿透进入溶菌酶的疏水核心,与溶菌酶肽链的非特异性结合导致溶菌酶二级结构由α-螺旋向β-折叠和β-转角转变,并导致溶菌酶表面疏水性略微增强。亚精胺与溶菌酶的结合降低了溶菌酶对底物溶壁微球菌的亲和力和最大反应速率,低浓度的亚精胺对溶菌酶的活性具有显著的抑制作用。