Optical resolution via catalytic generation of chiral auxiliary

A new catalytic method for separating enantiomers of racemic compounds is proposed. Catalytic asymmetric addition of racemic trans-2-substituted cyclohexanols to imines provided diastereomeric mixtures of aminals, and the subsequent separation of the enantiomers by silica-gel column chromatography and the hydrolysis of the aminals produced the alcohols in an optically active form.     

Thermodynamic properties of gaseous cerium phosphate studied by Knudsen effusion mass spectrometry

Gaseous CePO₂ has been identified by Knudsen effusion mass spectrometry during vaporization of CeO₂ and magnesium diphosphate from tungsten double, two‐temperature effusion cell. Structure and molecular parameters of gaseous cerium phosphate under study were determined using quantum chemical calculations. On the basis of equilibrium constants measured for gas‐phase reaction, standard formation enthalpy of CePO₂ was determined to be ?508 ± 41 kJ ? mol^?1 at the temperature 298 K.     

Biological applications of amide and amino acid containing synthetic macrocycles

ABSTRACT

Amino acid derived macrocycles with elaborate well-defined stereochemistry are a unique class of compounds that have been isolated from natural sources. Macrocycles like cyclosporine, octreotide, and valinomycin have been used in multiple applications, like drugs or ion sensors. Chemists have long been fascinated by the unique molecular recognition capabilities of these macrocycles and tried to design synthetic analogs with similar functions. This article is focused on reviewing current research on amide and amino acid containing macrocycles that have been developed in research laboratories for biological recognition, specifically for anion sensing, ion transport, carbohydrate sensing, and peptide sensing.     

光固化阻燃单体、树脂合成及其阻燃机理研究

本文综述了过去十余年间中国科技大学施文芳教授研究组在光固化阻燃技术领域的工作成果，主要包括活性单体、稀释剂、光固化树脂配方等体系，品类有磷酸酯类单体、含磷丙烯酸酯、超支化丙烯酸酯树脂、膦酸酯类单体和树脂、丙烯酸化环状磷腈、甲基丙烯酸化三聚氰胺、含磷环氧单体等十余种。同时介绍了这些配方体系的合成、性能和应用方法，以及对其热降解、阻燃性能评价和阻燃机理的研究。     

Co3+-Rich Na1.95CoP2O7 Phosphates as Efficient Bifunctional Catalysts for Oxygen Evolution and Reduction Reactions in Alkaline Solution

Implementing sustainable energy conversion and storage technologies is highly reliant on crucial oxygen electrocatalysis, such as the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). However, the pursuit of low cost, energetic efficient and robust bifunctional catalysts for OER and ORR remains a great challenge. Herein, the novel Na-ion-deficient Na_2−xCoP₂O₇ catalysts are proposed to efficiently electrocatalyze OER and ORR in alkaline solution. The engineering of Na-ion deficiency can tune the electronic structure of Co, and thus tailor the intrinsically electrocatalytic performance. Among the sodium cobalt phosphate catalysts, the Na_1.95CoP₂O₇ (NCPO5) catalyst exhibits the lowest ΔE (E_J10,OER−E_J−1,ORR) of only 0.86 V, which favorably outperforms most of the reported non-noble metal catalysts. Moreover, the Na-ion deficiency can stabilize the phase structure and morphology of NCPO5 during the OER and ORR processes. This study highlights the Na-ion deficient Na_2−xCoP₂O₇ as a promising class of low-cost, highly active and robust bifunctional catalysts for OER and ORR.     

Influence of pyridine oximate and quaternized pyridinium oximate ions on the hydrolysis of phosphate esters in cationic microemulsions

Kinetic studies have been performed to understand the hydrolytic potencies of oximate (2- and 4-pyridinealdoxime) and its functionalized oximate (4-(hydroxyiminomethyl)-1-alkylpyridinium bromide) ions (alkyl?=?C₁₀H₂₁ (4-C₁₀PyOx^-); alkyl?=?C₁₂H₂₅ (4-C₁₂PyOx^-)) in the cleavage of phosphate esters, diethyl p-nitrophenylphosphate (Paraoxon) and p-nitrophenyl diphenyl phosphate (PNPDPP) in a cationic (O/W) microemulsion system (ME) over a pH range 7.5 to 11.0 at 300?K. The k_obs values for the reaction of paraoxon with oximate and its functionalized oximate were determined in different microemulsion composition and the kinetic rate data shows that k_obs values increases with increasing water content. The specificity of different chain length of alcohols (n-butanol, n-pentanol, n-hexanol and n-octanol) was also investigated in hydrolytic reactions of paraoxon for different microemulsion composition.     

The influence of temperature on the phase behavior of ionic liquid aqueous two-phase systems

In this article, the equilibrium behavior of solutions of 1-ethyl-3-methylimidazolium dimethyl phosphate ([Emim]DMP) and ethyl acetate or acetone in aqueous two-phase system (ATPS) was discussed to understand the liquid–liquid equilibrium (LLE) behavior of these organic solvents. Thus, we determined phase diagrams and LLE data at 303.15, 308.15, 313.15, and 323.15 K for the investigated biphasic systems. Four empirical equations were used to study the tie lines. The results showed that for the [Emim]DMP?+?acetone?+?water biphasic systems within the investigated temperature range, temperature influences the phase behavior, but for the [Emim]DMP?+?ethyl acetate?+?water biphasic systems within the investigated temperature range, there are no notable changes on the phase behavior with rising temperature. The results may have important applications for the separation of antibiotics and for the recovery of ionic liquids (ILs).     

用于 NH3 选择催化还原 NO 反应的新型 Ce-P-O 催化剂

 报道了一种新型的可用于氨选择催化还原氮氧化物的 Ce-P-O 催化剂. 在空速为 20 000 h?1, 较宽的温度范围内经 500 oC 焙烧的 Ce-P-O 催化剂上表现出了较高的 NO 转化率 (可达到 90% 以上). 与 V-W-Ti 催化剂相比, 该催化剂具有一定的耐水蒸气和 SO2 能力以及较好的抗碱中毒性能.     

静电纺丝法制备聚乳酸/纳米磷酸钙复合纳米纤维及其表征

首先合成了纳米磷酸钙(NCP),用扫描电镜(SEM)和X射线衍射(XRD)进行了表征.再利用静电纺丝法制备了PLA/NCP复合纳米纤维,对纤维进行了TEM,SEM,XRD以及单轴拉力测试的表征.TEM和XRD测试表明,NCP已成功掺杂到聚乳酸纤维中,获得的纤维为复合纤维.SEM测试表明,NCP在溶液中浓度较小时,复合纳米纤维的形貌变化不大;NCP浓度超过PLA质量的7%后,纤维表面出现粒状物;随着浓度继续增大,粒状物逐渐增多,最后很难成纤.拉伸实验结果表明,复合纤维拉伸强度先随着NCP浓度的增加而增大,但NCP浓度超过7%后拉伸强度随着浓度的增加反而减小.     

盐酸法制备低氟含量饲料级磷酸氢钙的工艺研究

在不添加任何除氟剂的条件下,用盐酸浸取磷矿,通过调整工艺参数和采用特殊的试验条件,制备了低氟含量饲料级磷酸氢钙;着重探讨了盐酸浓度、反应时间、静置时间、温度、鼓气速率等因素对磷酸氢钙中氟含量的影响.结果表明,在盐酸溶解过程中减少氟的溶出,有利于在反应中同步降低氟含量;得到的磷酸经简单的过滤、中和,可用于制备氟含量低达0.1%(低于国家标准0.18%)的饲料级磷酸氢钙.