有机天然产物化学实验的教学改革与实践

Natural product chemistry experiments, which train the students to master the basic skills for extraction, separation and identification of the active components of natural products, and acquaint with the research methods of natural product chemistry, are an important part of organic chemistry laboratory. This paper analyzes the common problems related to the current natural products chemistry laboratories in domestic universities. In recent years, we carried out the reforms of the teaching contents, teaching conditions, and teaching methods. The teaching practices show that the students' learning interest and efficiency, the abilities to analyze and solve problems, and the scientific research abilities have been trained and strengthened. The teachers' experimental teaching level and teaching quality have been greatly improved.     

Transparent Coating with TiO2 Nanorods for High-performance Photocatalytic Self-cleaning and Environmental Remediation

High-performance self-cleaning coatings are highly desired by the industry and market. Herein, we synthesized two kinds of ultrafine TiO₂ nanocrystals, one is anatase dots with a diameter of 5 nm, and the other is rutile rods with 1.5 nm in width and 7 nm in length. The prepared TiO₂ nanocrystal is highly dispersed and stable in water over a month. The coating can be fabricated via a simple spraying method, displaying excellent optical properties and photocatalytic performance on self-cleaning and surrounding environment remediation. The transmittance of glass remains 80%-90% for visible and near-infrared light after 30 cycles of spray. RhB solution(50 mg/L) was applied to the coating surface and form a solid RhB layer was formed, which can be completely removed in 30 min's light irradiation. RhB aqueous solution(100 mL, 5 mg/L) was purified after 180 min by a 10 cm×10 cmglass, on which the coating was sprayed 30 times. The concentrations of formaldehyde and PM 2.5 in surrounding air displayed a significant decrease along 50 min's monitoring. This high-performance coating shows great potential for constructing functional coating on various substrates for industrial applications.     

碳酸酯把手改构Wang树脂及其性能

基于碳酸酯结构易于亲核脱除的原理, 使用氯甲酸氯甲酯改构Wang树脂, 并探究了改构树脂与首位氨基酸的缩合效率. 实验结果表明, 改构后的Wang树脂与20种Fmoc保护氨基酸均能达到70%以上的缩合效率; 且对于带有较大侧链基团的Fmoc保护氨基酸, 通过降低树脂取代度或延长反应时间可提高其连接率. 为了验证改构后的碳酸酯型树脂在裂解时侧链未受到影响, 设计合成了3种模型肽, 并用温和裂解剂3-吡啶甲醛肟铯盐进行裂解. 实验结果表明, 利用改构树脂能得到侧链全保护的肽片段, 可初步应用到长链困难肽的合成中.     

环氧树脂的飞行时间次级离子质谱

用飞行时间次级离子质谱结合银离化方法了集成电路封装用环氧模塑料的主要成分－－领甲酚环氧树脂。实验中测得ｎ＝０－４的树脂分子及相应的水解成分。碎片离子中除了芳香化合物通常具有的碎片外,还有反映树脂结构的碎片,通过对银离化了子的分析,推断中间不上的侧链是最可能断裂的     

核苷羧酸酯类化合物的酶法合成及其应用

核苷羧酸酯是一类在有机合成、核苷化学以及医药等领域具有重要应用价值的化合物. 近年来, 该类化合物的酶法合成以其绿色、高效、高选择性等优点而成为新的研究热点. 综述了近年来该领域的研究进展.     

固定化扩展青霉脂肪酶的制备及其在玉米油转酯反应中的应用

采用吸附法对来源于扩展青霉Penicillium expansum的脂肪酶进行了固定化.从20种不同来源的树脂中筛选出固定化效率高且价格低廉的D4020树脂作为载体,系统研究了固定化条件对固定化效率及固定化酶转酯活力的影响.结果表明,最适加酶量、缓冲液pH和吸附时间分别为0.7 g/g、9.4和4 h.冻干时添加0.5%的半乳糖有助于提高固定化酶的转酯活力.在上述优化条件下,固定化酶的转酯活力为404.0 U/g,而所用的游离酶不能催化该转酯反应.利用该固定化酶催化玉米油转酯反应生产生物柴油时,叔戊醇为适宜的反应介质,其最适添加量为0.5 ml/g;适宜的酶量、加水量和反应温度分别为60.6 U/g、油重的1.2%和35℃.按醇/油摩尔比为1的比例分别在反应0、2和6 h时加入甲醇,在优化反应条件下,反应24 h后甲酯产率达85.0%;固定化脂肪酶具有较好的操作稳定性,反应10批次时,相对酶活力为62.8%.     

铈镁铝混合氧化物催化剂的脱NOx性能

 用共沉淀法制得Mg-Al水滑石和二氧化铈的混合物,经750 ℃热活化,得到铈镁铝混合氧化物催化剂. 考察了催化剂的组成、反应温度、反应体系中氧含量、水蒸气及二氧化硫的存在对NO和CO反应活性的影响. 结果表明,铈镁铝混合氧化物催化剂具有较高的脱NOx活性,并具有优异的水热稳定性和一定的抗氧性及抗二氧化硫毒化的能力.     

无溶剂系统中固定化脂肪酶催化废油脂转酯生产生物柴油

 探讨了无溶剂系统中固定化脂肪酶Novozym 435催化餐饮业废油脂转酯生产生物柴油. 反应副产物甘油可吸附在固定化酶载体表面,采用丙酮洗涤除去甘油可提高酶的稳定性. 适宜的醇/油摩尔比、酶用量、反应温度和摇床转速分别为1, 6.6 U/g, 35～40 ℃和150 r/min,不宜加水到反应体系中. 采用分步加入甲醇的方式可减轻甲醇对酶的毒害作用. 分别在反应进行到6和14 h时用丙酮除去酶表面的甘油,然后按醇/油摩尔比为1的比例加入甲醇继续反应,反应30 h后产物中的脂肪酸甲酯含量为88.6%. 连续反应300 h后,酶活性基本没有下降.     

5-氟尿苷5’-棕榈酸酯的酶法合成

考察了10 ml丙酮-四氢呋喃(85/15,体积比)混合溶剂体系中,各关键因素对脂肪酶Lipozyme TL IM催化5-氟尿苷5’-棕榈酸酯合成反应的影响.结果表明,添加分子筛能有效除去溶剂中的水分,从而极人地提高了目标产物收率.在最优反应条件下,该体系被成功放大至200 ml (5-氟尿苷克级用量),产物收率高达9...