微波相转移催化合成DL—苯丙氨酸

在微波作用下,仅用1min便完成了苯甲醛亚胺的固—液相转移催化苄基化反应,然后经酸水解得到d1—苯丙氨酸,全程总产率为62.5×10(-2)。     

2E－不饱和酰胺的立体选择合成法

以二（苯腈）－二氯化钯为催化剂，在固液相转移条件下，通过芳卤与Ｎ，Ｎ－二乙基丙烯酰胺发生偶联反应，生成了Ｅ式α，β－不饱和酰胺。碘代芳烃的偶联产率较高，从而建立了简便的２Ｅ－不饱和酰胺立体选择合成法。     

光学活性配合物的合成、拆分和性能研究——Ⅲ.fac-、mer-〔Co(β-ala)3〕的手性固定相拆分和其对映体的异构化外消旋反应机理

本文用QAE-Sephadex-Sb_2(d-tart)_2~(2-)为手性交换固定相,50％乙醇水溶液为淋洗剂,在柱尺寸为80cm×2.2cm,淋洗速度为5.0ml/20min下完全拆分了1.0g fac-[Co(β-ala)_3];用同一手性固定相和淋洗剂在淋洗速度为1.2ml/20min下mer-[Co(β-ala)_3]的拆分量可增至0.78g。 fac-、mer-[Co(β-ala)_3]的四种对映体在1.56×10~(-2)M HClO_4介质和中性水溶液中的异构化外消旋反应的产物用Na~+型SP-Sephadex C-25柱分离后,用分光光度法和旋光仪测定了它们的浓度和旋光度。实验结果表明,这些对映体的异构化外消旋反应比较可能是按Werner首先提出的断键-分子内重排的机理进行。机理研究正在深入进行。     

Highly Effective Phenol Hydroxylation over Ti-ZSM-5 Catalyst Prepared Using B-ZSM-5 as Precursor 以B-ZSM-5为母体合成Ti-ZSM-5高效苯酚羟基化催化剂

 以改进方法合成的B-ZSM-5为母体,采用气固相同晶取代法合成了较小晶粒的Ti-ZSM-5分子筛. 考察了样品的物化性能和催化苯酚羟基化性能. 结果表明: 所合成的小晶粒Ti-ZSM-5具有较高的结晶度,尺寸为100~200 nm,且不含锐钛矿型TiO2,对苯酚羟基化反应的催化性能优异.     

LiCoO2中锂离子固相扩散系数随循环次数的变化

The solid diffusion coefficient of lithium-ion in LiCoO₂ cathode material has been investigated by the capacity intermittent titration technique (CITT) at different voltages and at different charge/discharge cycles. By SEM, XRD and FTIR techniques, the structure of LiCoO₂ was studied before and after charge-discharge cycles, and the relationship between solid diffusion coefficient and crystal structure was further discussed. CITT results show that the value of Li⁺ solid diffusion coefficient of LiCoO₂ is about 10^-12 cm²·s^-1. During the whole charge-discharge cycles, the Li⁺ solid diffusion coefficient decreased within the voltage of 4.0～4.3 V, which is attributed to the change of the structure of LiCoO₂.