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81.
The microwave-assisted dry media technology was utilized for the synthesis of some novel derivatives in the Hantzsch—Biginelli reaction. In this eco-friendly approach, the usage of organic solvents and hazardous reagents resulting in corrossion of materials was minimized, giving high yields of products within a short reaction time. 相似文献
82.
The micro construction of poly(epsilon-caprolactone) (PCL) and poly(L-lactic acid) (PLLA) blend films fabricated by solution casting under microwave irradiation was investigated by selective enzymatic degradation and scanning electron microscopy (SEM). The results were totally different from the blends obtained by conventional methods. The blend was more homogeneous and the PCL continuous phase more compact as no spherulites and tiny zone separation were observed from the film surface and no PCL network was observed inside the film, and the degradation of a PCL plank by Pseudomonas lipase was significantly retarded. The distributed PLLA micro spheres were enlarged and amorphous. The thermal behavior of the blend by microwave heating revealed that PCL and PLLA underwent a melting process, which induced the variations of the PCL phase and PLLA spheres. The weight loss caused by degradation of the PCL/PLLA blend obtained by conventional methods (B50c) is greater than that of the blend obtained by microwave methods (B50m), which reflects the change in morphology from a loose PCL network (B50c) to a dense PCL plank (B50m). 相似文献
83.
为了研究从简单易得的原料在无催化剂的条件下一锅法合成N-甲基十氢吖啶-1,8-二酮化合物,我们以各类醛(脂肪醛、芳香醛、二醛)、达咪酮或1,3-环己二酮和甲胺为原料,以乙二醇或水为溶剂,经微波辐射,一步反应得到了一系列N-甲基十氢吖啶-1,8-二酮化合物。反应时间从传统热反应的4-5小时缩短至2-10分钟,产率较高(56-95%),并且不需要使用催化剂。该反应后处理方便,只需要简单洗涤,环境友好,为合成此类化合物提供了一种简便、有效的合成方法。该方法不仅适用于一元脂肪醛、芳香醛,还适用于芳香二醛,因此可以合成含有一个或两个十氢吖啶结构单元的杂环化合物。 相似文献
84.
自组装合成纳米复合TiO2-ZnO介孔材料及其光催化性能 总被引:8,自引:0,他引:8
以TiCl4, ZnSO4•7H2O为原料, 尿素为沉淀剂, 利用可溶性淀粉大分子链的空间位阻效应和高分子网络的阻隔作用, 以纳米级碳黑为模板, 采用微波加热、均相沉淀法合成出了一系列纳米TiO2-ZnO复合介孔材料. XRD分析证明反应前驱体为非晶态, 500 ℃以上转变为锐钛矿结构的TiO2和ZnTiO3, 当Ti∶Zn=1(摩尔比)时, 产物全部为ZnTiO3 (TiO2•ZnO). TEM形貌观察结合N2吸附表明, 基本粒子为球形, 粒径15~20 nm. 最可几孔径8~10 nm. EDS分析证明产品中Ti∶Zn的分析测定值与实际的投料值基本一致, 并且掺杂均匀性好. 光吸收及光催化实验发现Zn含量为50%时, 光催化效果最好, 在日光照射90 min后, 此TiO2-ZnO复合材料对藏蓝染料溶液降解率可达到100%, 其光催化反应符合一级动力学方程. 相似文献
85.
微波辐射下三组分“一锅法”合成5-芳基-1,5,6,7,8,9-六氢化-2H-吡唑[5,4-b]并喹啉-6-酮 总被引:1,自引:0,他引:1
在微波辐射下以芳醛、1,3-环己二酮或达米酮和氨基吡唑为原料, 用乙二醇作能量转移剂, 三组分“一锅法”快速合成了一系列吡唑[5,4-b]并喹啉类化合物. 该方法速度快(30~90 s), 产率高(88%~98%), 环境友好. 产物结构通过红外光谱、核磁共振谱和元素分析证实, 化合物4e的单晶经X射线衍射分析, 进一步确证了产物结构. 相似文献
86.
87.
A.?H.?Naik N.?V.?Thakkar S.?R.?DharwadkarEmail author K.?D.?Singh Mudher V.?Venugopal 《Journal of Thermal Analysis and Calorimetry》2004,78(3):707-713
Sodium zirconium phosphate [NaZr2P3O12], a potential ceramic matrix for fixation of high level nuclear waste, was synthesized by heating the mixture of sodium carbonate [Na2CO3], zirconyl nitrate hydrate [ZrO(NO3)2·5H2O] and ammonium dihydrogen phosphate [NH4H2PO4] in air, in a resistance heated furnace and a microwave heating system respectively in the temperature range 450 to 650°C. The mixture heated for 1 h in a resistance furnace at 450°C yielded a poorly crystalline NaZr2P3O12 [NZP]. Increasing the temperature to 650°C produced a highly crystalline product. The same mixture heated in a microwave oven at 450°C for 1 h however, yielded the most crystalline NZP.In an alternate method, the mixture of sodium dihydrogen phosphate (NaH2PO4), zirconium dioxide (ZrO2) and diammonium hydrogen phosphate [(NH4)2HPO4] heated in resistance furnace at 650°C for the same period did not react in air. It also did not yield the pure product at 450°C when heated in microwave assembly for 1 h.The authors thank the Board of Research in Nuclear Sciences (BRNS) of the Department of Atomic Energy (DAE) for the financial support for this work under the project No. 2000/37/19/BRNS/1959 dtd09-02-02. 相似文献
88.
90.
Joan Fraga-DubreuilJean Pierre Bazureau 《Tetrahedron》2003,59(32):6121-6130
The first report of the use of task-specific ionic liquid as synthetic equivalent of ionic liquid-phase matrice for the preparation of a small library of 4-thiazolidinones is reported in this paper. The starting (ethyleneglycol)ionic liquid-phase is functionalized in good yields with 4-(formylphenoxy)butyric acid by using usual esterification reaction conditions (DCC/DMAP as catalyst). The synthesis of the ionic liquid-phase bound 4-thiazolidinones was performed by a one-pot three-component condensation under microwave dielectric heating. The final cleavage under microwave/catalysis strategy provides the expected 4-thiazolidinones in high purity after flash-chromatography purification. According to the ionic liquid-phase organic synthesis (IoLiPOS) methodology, it was found that optimized reaction conditions were performed by standard analytical methods (NMR, TLC). The 1H, 13C NMR spectrum of some representative 4-thiazolidinones and ionic liquid-phase bound benzaldehyde are also reported. 相似文献