臭氧化合成聚乙二醇醛基衍生物

以甲氧基聚乙二醇为原料, 通过烯烃化得到甲氧基聚乙二醇烯烃,最后经臭氧化反应得到甲氧基聚乙二醇醛基衍生物。 通过核磁共振波谱仪(NMR)和基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)对产物的结构和性能进行了表征。 结果表明,该方法合成的产物纯度高,无副产物,甲氧基聚乙二醇乙醛和聚乙二醇丙醛的产率分别高达98%和99%,取代度分别为90.87%~99.91%和98%~100%。     

Defluorinative C(sp3)−P Bond Construction for the Synthesis of Phosphorylation gem‐Difluoroalkenes under Catalyst‐ and Oxidant‐Free Conditions

Defluorinative C(sp³)?P bond formation of α‐trifluoromethyl alkenes with phosphine oxides or phosphonates have been achieved under catalyst‐ and oxidant‐free conditions, giving phosphorylation gem‐difluoroalkenes as products. α‐Trifluoromethyl alkenes bearing various of aryl substituents such as halogen, cyano, ester and heterocyclic groups are available in this transformation. The results of control experiments demonstrated that the mechanism of dehydrogenative/defluorinative cross‐coupling reactions was not a radical route, but might be an S_N2′ process involving phosphine oxide anion.     

千瓦级半导体抽运的固体热容板条激光器

报道了千瓦级激光二极管面阵抽运固体热容激光器的理论与实验研究,分别采用Nd∶YAG单板条和双板条串接的热容激光器,利用热容激光器的理论计算模型计算了在一定的工作时间内激光输出特性,并进行了实验验证。实验中采用的晶体尺寸均为59mm×40mm×4.5mm,对单板条进行抽运时平均功率大约为5.6kW,双板条串接时为11.2kW,重复频率为1kHz,占空比为20%。实验中观察了1s的工作时间内脉冲能量输出的波动情况,单板条时单脉冲能量输出最大为1.3J,在1 s后单脉冲能量输出下降到开始的70%左右,而双板条串接时单脉冲能量输出最大为2.06J,在1s后单脉冲能量输出下降到开始的50%左右,对单块晶体采用通水冷却的准热容热管理模式能有效地降低其热效应。     

Synthesis and near infrared electrochromic properties of metallodithiolene complexes

Four metallodithiolene complexes[4,8-bis(octyloxy)-1,3,5,7-tetrathia]?di[1,1′-bis(diphenylphosphino)ferrocene?palladium(II)](3),[4,8-bis(octyloxy)-1,3,5,7-tetrathia]di[1,3-bis(diphenylphosphino)propane?nickel(II)](4),[4,8-bis(octyloxy)-1,3,5,7-tetra-thia]?[1,1′-bis(diphenylphosphino)ferrocene?palladium(II)]?[1,3-bis(diphenylphosphino)propane·nickel(II)](5)and di[4,8-bis(octyloxy)-1,3,5,7-tetrathia]?[1,1′-bis(diphenylphosphino)ferrocene?palladium(II)]?nickel(II)(6)were synthesized and the near-infrared(NIR)electrochromic properties were studied.The spectroelectrochemical spectra and the electrochromic parameters such as optical contrast,switching time,optical density change,electrochromic efficiency and optical attenuation of complexes 3–6 were investigated in detail.The symmetric binuclear complex 4 showed relatively high electrochromic efficiency of63.0 and 75.4 cm~2/C both in the two oxidation states.The complexes exhibited excellent electroactive/electrochromic stability characterized by chronoamperometry(4000 cyclic switches).     

中国制氢技术的发展现状

氢能是一种高效清洁的二次能源,在实现“碳中和”目标中起重要作用。随着制氢规模不断扩大、制氢成本不断降低,氢能将有望与电能共同成为二次能源主体,通过氢电互补推动我国能源结构转型、降低碳排放、保障我国能源安全。目前,我国已成为世界第一大产氢国,主要有三类工业制氢路线:化石燃料重整制氢、工业副产氢和清洁能源电解水制氢。依托清洁能源发展起来的其他制氢新技术,如太阳能光解水制氢、生物质制氢、核能制氢等也受到广泛研究和关注。此外,制氢系统组成复杂,建模和优化难度高,人工智能在制氢系统的预测、评估和优化方面表现出独特的优势,受到国际学者的关注。本文结合最新研究进展,对上述制氢路线的发展情况进行了综述,并通过技术成熟度、经济性和环保性比较,结合国情对我国未来氢气供应结构做出展望。同时,本文综述了人工智能在制氢系统中的最新应用进展,以期为我国制氢工艺发展提供新思路。     

Hyperelasticity, viscoelasticity, and nonlocal elasticity govern dynamic fracture in rubber

Dynamic cracks in rubber can spontaneously oscillate under certain biaxial strain conditions [R. D. Deegan et al., Phys. Rev. Lett. 88, 014304 (2002)]. We have found that this unusual phenomenon can be understood from the unique mechanical properties of rubber: hyperelasticity, viscoelasticity, and nonlocal elasticity. While all these are important, the decisive role of nonlocality needs to be particularly emphasized. Through numerical simulations with a lattice model, we have quantitatively reproduced the experimental results.     

聚合物保护基团在有机合成中的应用

本文论述了聚合物保护基团在对称双功能基单保护合成不对称化合物,作为助剂合成手性化合物和作为载体合成昆虫性信息素和不对称卟啉,酞菁类化合物方面的应用。     

聚苯乙烯磺酰氯与三氯化铁复合物的合成及其对乙酸和正丁醇酯化反应的催化作用

聚苯乙烯磺酰氯树脂１与三氯化铁或三氯化铁的六水合物在二氯乙烷的回流温度下分别制得了复合树脂２和复合树脂３。这两种树脂在二氯乙烷中分别用无水ＨＣＬ处理分别得到复合树脂４和复合树脂５。用对硝基氯苯作指示剂测得复合树脂２的Ｈａｍｍｅｔｔ酸度常数为－１２．７０。这些树脂在６０℃下催化乙酸和丁醇（摩尔比为１：１３）的酯化反应中虽然树脂３没有明显的催化活性，但其余三种复合树脂的催化活性是其母体聚苯乙烯磺酰氯树脂的３～４倍，是强酸树脂催化剂Ｄ７２的４～６倍。     

CATALYSIS OF POLYSTYRENE N-HYDROXYL SULFONAMIDE FOR ESTERIFICATION OF BUTANOL WITH ACETIC ANHYDRIDE

Polystyrene N-hydroxyl sulfonamide resin l was prepared and used to catalyze the esterification of n-butanol and acetic anhydride. The mechanism of catalytic esterification proved by IR spectra of the resins was found that O-H and N-H of the N-lrydroxyl sulfonamide resin reacted with the acetic anhydride respectively to form the active intermediate polystyrene N.O-diaceyl sulfonamate which was cleaved by n-butanol to produce butyl acetate. The catalytic esterification by resin I was in good agreement with the kinetic model of “bi-bi-ping-pong“ mechanism.     

胶束电动毛细管色谱法分离酮康唑手性异构体

1引言胶束电动毛细管色谱法（MECC）综合了反相高效液相色谱的分配机理和毛细管区带电泳的电渗及电泳机理,实现了对电中性物的分离。由于环糊精（CD）外表面具有亲水性,当其与胶束共存时,不能进入胶束,所以溶液存在三相即：胶束相、水相和CD相。异构体通过与CD形成不同稳定常数的主-客体络合物而达到手性识别,由于十二烷基硫酸钠（SDS）的高疏水性,该方法对分离电中性和疏水性化合物具有突出的优越性。酮康华（ketoconazole）属口服咪唑类抗真菌合成药物,到目前为止,人们对其它手性药物拆分进行了较多的研究,但对酮康唑的研…