藤黄酸重排反应产物研究

藤黄酸能显著抑制多种人类肿瘤细胞的增殖,在酸性环境中易发生重排反应,其重排产物对肿瘤细胞也具有很强的抑制作用.通过波谱技术确定了两个藤黄酸的重排反应产物的结构并归属了其波谱数据.细胞毒活性测试显示,两个重排产物对A549,HCT116和MDA-MB-231显示很强的抑制作用.     

介孔分子筛MCM-48的氮化与表面胺化及其碱催化反应性能

以介孔分子筛MCM-48为前驱体,通过表面胺化和高温NH3氮化方法制备出两种碱性分子筛.采用X射线衍射(XRD)、N2-吸附脱附、透射电镜(TEM)、红外光谱(FT-IR)、热重分析(TG)和哈密特指示剂法对上述分子筛的结构及表面酸碱性进行了详细表征,并通过苯甲醛与丙二腈的Knoevenagel缩合反应对其碱催化活性及稳定性进行了考察和对比.结果表明,表面胺化和高温氮化的方法均可制备出碱性介孔分子筛,且均在Knoevenagel碱性探针反应中表现出较好的碱催化活性,但与后者相比,前者制备的碱性分子筛具有更强的表面碱性和更好的反应稳定性.     

Study on preparation and properties of polyether polytriazole elastomers

To explore the application of click chemistry in the field of elastomer materials, propargyl-terminated ethylene oxide-tetrahydrofuran copolymer(PTP(E-co-T)) was prepared from hydroxyl-terminated ethylene oxide-tetrahydrofuran copolymer(P(E-co-T)) by end-etherisation modification. FTIR and 13C-NMR results indicate that P(E-co-T)-terminated hydroxyl was etherified thoroughly, yielding the target product PTP(E-co-T), and the content of terminated alkynyl of PTP(E-co-T) was evaluated to be 0.428 mmol·g-1. Using a polyazide compound as a cross-linker, polytriazole elastomers with various functional molar ratio(R) values were prepared from PTP(E-co-T) by virtue of the Cu AAC reaction. Mechanical property tests indicate that with the increase in R, the modulus E and stress σb of the polytriazole elastomers first increase and subsequently decrease, whereas the strain first decreases and later increases. The mechanical properties of the polytriazole elastomers show a parabolic dependence on the R value. Near the stoichiometric ratio, E and σb show maxima and the strain εb shows a minimum. Swelling tests demonstrate that the apparent molecular weight of polytriazole elastomer strands also first decreases and subsequently increases. At the stoichiometric ratio, the network structure possesses strands with a minimum apparent molecular weight and a maximum apparent density. Dynamic mechanical analysis reveals that the polytriazole elastomers presented damping peaks at approximately-64 °C, corresponding to the glass transition of copolyether strands, and the elastomer exhibited the lowest dissipation factor tanδ at the stoichiometric ratio. Thermal analysis suggests that the weight-loss process of the polytriazole elastomer is characteristic of one-step decomposition, and the elastomer begins to decompose from polyether strands, not triazole groups.     

Methane dehydroaromatization with periodic CH4-H2 switch:A promising process for aromatics and hydrogen

Long-term stability test of Mo/HZSM-5-N catalysts(HZSM-5-N stands for nano-sized HZSM-5) in methane dehydroaromatization(MDA)reaction has been performed with periodic CH4-H2 switch at 1033-1073 K for more than 1000 h.During this test,methane conversion ranges from 13% to 16%,and mean yield to aromatics(i.e.benzene and naphthalene) exceeds 10%.N2-physisorption,XRD,NMR and TPO measurements were performed for the used Mo/HZSM-5 catalysts and coke deposition,and the results revealed that the periodic hydrogenation can effectively suppress coke deposition by removing the inert aromatic-type coke,thus ensuring Mo/HZSM-5 partly maintained its activity even in the presence of large amount of coke deposition.The effect of zeolite particle size on the catalytic activity was also explored,and the results showed that the nano-sized zeolite with low diffusion resistance performed better.It is recognized that the size effect was enhanced by reaction time,and it became more remarkable in a long-term MDA reaction even at a low space velocity.     

气基磁化焙烧回收包头稀土尾矿中铁的研究

试验采用磁化焙烧-磁选的方法来回收包头稀土尾矿中的Fe。考察了还原球团的粒径、焙烧温度、还原气体的成分、还原气气体流量、焙烧时间对于磁化焙烧回收Fe的影响。在焙烧温度为580℃,CO与CO2的浓度比为40∶60,还原气体气流量为1.2 L·min-1,焙烧时间为60 min的条件下对球团进行磁化焙烧,并将焙烧后的球团进行磨矿,使得-200目的物料占物料总重量的95%。将磨矿后的物料置于磁场强度为233 k A·m-1的磁选管中进行磁选,可以得到品位为60%左右的铁精矿,其铁回收率达到70%左右。     

自然光照下PEG/PAA凝胶在Fe~(3+)/CA溶液中的凝胶-溶胶转化行为

将PEG/PAA凝胶浸入铁/柠檬酸(Fe3+/CA)溶液中,自然光照一定时间可实现凝胶-溶胶的相互转化,而且转化行为受溶液的组成及其p H影响。只有当溶液中[Fe3+]0∶[CA]0≤1∶2,且溶液的p H在1~6之间,该转化才会发生,通过改变溶液中[Fe3+]0∶[CA]0的值或溶液的p H可以有效地控制其转化速率。此外,结果还表明,当凝胶转化为溶胶后,向其中加入高价金属阳离子,例如Fe3+、Al3+、Ce4+、Cu2+等,溶胶又会再次转化为凝胶。由于这种新颖的特性,该凝胶有望应用于药物释放、细胞培养等领域。