基于金属介导和离子液体的新型绿原酸印迹整体柱的制备及评价

选用1-乙烯基-3-乙基咪唑四氟硼酸盐([VElm]BF4,一种离子液体)作为功能单体,以Co2+为介导离子,结合1-丁基-3-甲基咪唑四氟硼酸盐([BMIM]BF4)/二甲基亚砜(DMSO)二元致孔体系制备了绿原酸印迹整体柱。经过对制备参数的考察,确定最佳比例为绿原酸:Co2+:[VElm]BF4:EDMA(乙二醇二甲基丙烯酸酯)(摩尔比)=1:1:5:20,[BMIM]BF4:DMSO=3:1(V/V),最大印迹因子达2.10。通过优化色谱条件,最终在乙腈:20 mmol/L乙酸钠缓冲液(pH 4.2)=70:30(V/V)时实现了绿原酸及其类似物的完全分离。由此可见,以离子液体为功能单体及致孔剂,在金属介导策略下制备的分子印迹聚合物可实现绿原酸的特异性识别及分离。     

Catalytic properties of mesoporous materials supported heteropoly acids for Baeyer-Villiger oxidation of cyclic ketones

Three mesoporous molecular sieves loaded silicotungstic acids, named HSiW/SBA-15, HSiW/MCM-41, HSiW/MCM-48, were prepared and characterised by XRD, FT-IR, TEM and SEM. The catalytic performance of the prepared materials for the Baeyer-Villiger oxidation of cyclic ketones was carried out in the presence of 30%H₂O₂ under mild conditions. These loading materials were proved to be efficient and reusable catalysts, they all exhibited excellent catalytic performance for the Baeyer-Villiger oxidation of cyclic ketones with 30% H₂O₂ as oxidant. Many cyclic ketones were efficiently converted to the corresponding lactones with up to 90% conversions and high selectivities under the optimum reaction conditions.

Cyclic ketones were efficiently oxidised by mesoporous materials sopported silicotungstic acid to the corresponding lactones with 30%H₂O₂ as oxidant. All of the catalysts showed promising recyclability in the reactions.     

核壳结构Ziegler-Natta复合催化剂的制备及其乙烯聚合

采用溶胶-凝胶法,将聚(苯乙烯-co-丙烯酸)(PSA)膜材料和氯化镁的复合物包覆在以硅胶为载体的TiCl3催化剂上,负载TiCl4后制得Ziegler-Natta复合催化剂.采用红外光谱、激光粒度仪和扫描电镜对催化剂进行了表征,结果表明该复合催化剂呈核壳结构.同时,考察了复合催化剂中膜的厚度和反应中的氢气含量对催化剂的聚合活性和聚乙烯性能的影响,实验发现,膜厚约为3μm的核壳结构复合催化剂活性良好,其具有带诱导期的平稳型动力学曲线;膜厚1.5μm的复合催化剂的活性接近于实验所用的以硅胶为载体的TiCl3催化剂,且其具有相似的衰减型动力学曲线.研究同时表明,不同的膜厚能够调节复合催化剂的氢调性能及所得聚乙烯的分子量分布.     

纤维素/明胶复合膜的超分子结构与性能

通过一种绿色的方法在NaOH/尿素水体系中制备出纤维素和明胶组成的复合膜(C/G),并且证明这两种大分子间存在强的氢键作用,导致明胶耐水性明显改善.同时,用戊二醛作为交联剂对复合膜化学交联,进一步提高其抗水性.通过红外光谱(FTIR)、紫外光谱(UV-Vis)、13C固体核磁共振谱、扫描电镜(SEM),力学和溶胀测试对...     

灵芝子实体水溶性多糖的分离和分子量测定

用磷酸盐缓冲液、热水、碱和热碱水分别从灵芝子实体分离出五种水溶性杂多糖ＧＬ１、ＧＬ２、ＧＬ３、ＧＬ４和ＧＬ５．紫外光谱、红外光谱、气相色谱及硫酸咔唑分析结果表明，它们主要由葡聚糖、木糖、甘露糖、半乳糖组成，ＧＬ３、ＧＬ４和ＧＬ５含葡萄糖醛酸．由粘度、光散射和膜渗透压法测定了特性粘度［η］、重均分子量Ｍｗ及数均分子量Ｍｎ，ＧＬ２、ＧＬ３和ＧＬ５多糖的Ｍｗ值分别为１２４×１０４、１２８×１０４和５８×１０４．实验结果表明这些杂多糖含水溶性Ｄ 葡聚糖，并且初步推断，用磷酸盐缓冲液提取出的杂多糖ＧＬ２中包含刚性链β Ｄ 葡聚糖     

镶炭泡塑对阴离子表面活性剂吸附性能的研究

提出了用镶炭泡塑处理含阴离子表面活性剂的废水，并通过实验证实，经活化的泡塑对ＬＡＳ有明显的富集作用，且发现将活化过的活性炭填镶进去，可形成具有复合功能的处理剂，对含ＬＡＳ废水的处理效果更佳。     

Decorating Single-Atomic Mn Sites with FeMn Clusters to Boost Oxygen Reduction Reaction

The regulation of electron distribution of single-atomic metal sites by atomic clusters is an effective strategy to boost their intrinsic activity of oxygen reduction reaction (ORR). Herein we report the construction of single-atomic Mn sites decorated with atomic clusters by an innovative combination of post-adsorption and secondary pyrolysis. The X-ray absorption spectroscopy confirms the formation of Mn sites via Mn-N₄ coordination bonding to FeMn atomic clusters (FeMn_ac/Mn-N₄C), which has been demonstrated theoretically to be conducive to the adsorption of molecular O₂ and the break of O−O bond during the ORR process. Benefiting from the structural features above, the FeMn_ac/Mn-N₄C catalyst exhibits excellent ORR activity with half-wave potential of 0.79 V in 0.5 M H₂SO₄ and 0.90 V in 0.1 M KOH as well as preeminent Zn-air battery performance. Such synthetic strategy may open up a route to construct highly active catalysts with tunable atomic structures for diverse applications.     

S-Shaped composition dependence of excess thermodynamic quantities for cyclohexane mixtures with globular alkanes

Expansion coefficients , isothermal compressibilities, thermal pressure coefficients and heat capacities have been measured at 25°C for the cyclohexane+trans-decalin system. An S-shaped composition dependence, positivelnegative for highllow cyclohexane compositions is found for C _p ^E dV ^E /dT and the thermal expansion contribution to C _p ^E namely VT. The thermal motion contribution to C _p ^E , namely C _v is close to zero. The positive excursion of these mixing quantities at high cyclohexane content is anomalous. Correspondingly, the mixing quantity-VT deviates strongly in this region from the predicted equality with H ^E . The literature and this work show that all these excess quantities behave similarly for cyclohexane mixed with cyclooctane, methylcyclohexane and some highly branched alkanes. The unusual composition dependence of the thermodynamic quantities is consistent with order occurring when any large alkane molecule of globular shape is added to cyclohexane. This is speculatively associated with an interference by the globular alkane with the relatively free rotation of cyclohexane molecules.     

A thermodynamic study of the aggregation process of oxacillin sodium salt in aqueous solution

The aggregation characteristics of oxacillin in aqueous solutions have been examined by means of conductivity measurements over the temperature range 288.15-313.15 K and by static light scattering measurements at 298.15 K. Two critical concentrations were detected in conductivity and light scattering over the concentration range 0-0.35 mol kg^-1. Light scattering measurements indicate the formation of dimers at the first critical concentration (0.024 mol kg^-1) and the subsequent formation of aggregates with an aggregation number of 8 at the second critical concentration (0.104 molkg^-1). The thermodynamic parameters of aggregation were derived from the critical concentration data using a mass-action model that has been modified for application to systems of low aggregation number. Values for the enthalpy of aggregate formation calculated by this method showed that the aggregation became increasingly exothermic with increasing temperature. The values of the two critical concentrations show that this penicillin, oxacillin, is more hydrophobic than other molecules of similar structure.