共查询到20条相似文献,搜索用时 93 毫秒
1.
Fe-MIL-101催化Paal-Knorr反应合成吡咯衍生物 总被引:1,自引:0,他引:1
以Fe-MIL-101为非均相催化剂,通过多种伯胺与2,5-二甲氧基四氢呋喃进行Paal-Knorr反应,高效合成相应的吡咯衍生物.在Fe-MIL-101结构中,裸露的Fe(Ⅲ)配位点作为催化活性中心参与吡咯衍生物的催化合成反应.同时Fe-MIL-101的高比表面积和大的孔尺寸确保了底物分子与催化活性中心的充分接触以及产物的自由脱离,从而促进了催化反应的快速进行.Fe-MIL-101在催化反应过程中具有很好的稳定性,多次循环使用后仍能表现出良好的催化性能.此外,该催化剂在伯胺(包括脂肪胺、芳香胺)与2,5-己二酮的Paal-Knorr缩合反应中也具有优异的催化性能. 相似文献
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
A. Kurganov 《Chromatographia》1996,42(1-2):17-24
Summary A computer spreadsheet application has been developed for the optimization of step-gradient elution conditions as applied in coupled-column RPLC for online clean-up and separation in the analysis of pesticide residues. The procedure is based on the experimentally determined retention behaviour of the analytes as a function of mobile phase composition. Retention and peak volumes of the analytes eluting under isocratic and one- and/or two-step gradient conditions can be calculated. For a given set of analytes, the spreadsheet systematically calculates the resolution of the least efficiently separated pair of peaks in the space defined by the eluotropic strengths of the mobile phases and the time at which the step-gradient takes place.The performance of the proposed procedure was tested and evaluated for the analysis of nine polar pesticides for which in a previous study adequate conditions had been found by computer-aided chromatogram simulation. the optimum conditions predicted by the procedure were in good agreement with those established experimentally and by simulation. The simultaneous production of data on retention, peak volume and resolution for a group of analytes under selected one- and/or two step-gradient elution conditions makes the calculation procedure highly productive and flexible in searching for and/or adjusting appropriate separation conditions. 相似文献
12.
A simple and efficient procedure for the synthesis of symmetrical bis-Schiff bases has been described that employs a condensation reaction of symmetrical primary bis-amine of 5,5′-methylenebis(2-aminothiazole) with a series of aromatic aldehyde derivatives under solvent-free conditions at elevated temperature. The advantages of these reactions are simplicity of the reaction procedure, short reaction times, simple workup, catalyst-free conditions, and pure products in good to excellent yields. Details of the reaction conditions are discussed. 相似文献
13.
《Green Chemistry Letters and Reviews》2013,6(4):263-267
Abstract An efficient and green procedure has been developed for the preparation of carbamatoalkyl naphthols by the one-pot condensation of aryl aldehydes, β-naphthol, and methyl carbamate in the presence of silica-supported Preyssler nano particles as a heterogeneous catalyst under solvent-free conditions. The present methodology offers several advantages such as excellent yields, simple procedure, easy work-up, and eco-friendly reaction conditions. The catalyst is easily prepared, stable, reusable, and efficient under the reaction conditions. 相似文献
14.
A variety of alcohols and phenols are efficiently acetylated with acetic anhydride in the presence of a catalytic amount of V(HSO4)3 in solution and under solvent free conditions.Mild reaction conditions,high yields of the products,easy procedure and selective acetylation of alcohols and phenols in the presence of amines and thiols are the main advantages of this procedure. 相似文献
15.
The photometric titration of the metal indicator complex MI with a ligand L is discussed. A tangent procedure is adopted for the determination of the end-point. From this procedure, in combination with an assumed maximum titration error, titration conditions have been derived. A procedure is introduced which, in conjunction with the derived titration conditions, permits the selection of a suitable titration medium by means of a diagram in which log K, log alpha and log chi are plotted vs. pH. The procedure is applied to determination of lead and zinc in the presence of citric acid, the medium used for their paper-electrophoretic separation. The use of citric acid introduces some limitations; it is shown that the method developed is generally applicable. 相似文献
16.
I. P. Sizeneva Yu. V. Ryabchevskikh A. A. Spiridonov 《Journal of Analytical Chemistry》2000,55(7):663-665
A procedure for the determination of sodium salts of methyl sulfamic acid as tertiary amines by acidimétrie titration in glacial
acetic acid was developed. The total error of the procedure did not exceed 1%. The procedure is simple and can be carried
out under ordinary laboratory conditions. 相似文献
17.
山楂叶中熊果酸提取工艺研究 总被引:8,自引:0,他引:8
以熊果酸的提取率为指标,采用单因素与正交实验相结合的方法对提取工艺进行了优化,得到最佳提取参数为:乙醇体积分数95%、提取温度85℃、提取时间110min、液固比5:1、提取次数3次。在该条件下,熊果酸提取率为93.47%。该工艺简单合理,为工业生产提供了理论参考。 相似文献
18.
Habib Firouzabadi Nasser Iranpoor Sara Sobhani Soheila Ghassamipour 《Journal of organometallic chemistry》2004,689(20):3197-3202
A broad, adaptable, high yielding and convenient procedure for the easy conversion of various α-hydroxyphosphonates to α-trimethylsilyloxyphosphonates under mild conditions with HMDS in the presence of a catalytic amount of magnesium triflate as a highly stable and a non-hygroscopic recyclable catalyst in neat conditions is described. In order to show the general applicability of this method, we have also applied this procedure successfully for the silylation of ordinary alcohols and phenols. 相似文献
19.
Yumei Zhang Tingli Yan Wei Cheng Jianming Zuo Weijie Zhao 《Tetrahedron letters》2009,50(24):2925-6515
A rapid and efficient procedure for allylation and benzylation of aldimines mediated by zinc powder under solvent-free conditions is described. The procedure is operationally simple, higher regioselective, and gives good to excellent yields. 相似文献
20.
Mukai C Kobayashi M Kubota S Takahashi Y Kitagaki S 《The Journal of organic chemistry》2004,69(6):2128-2136
A new procedure for constructing monocyclic five- and six-membered azacycles by the endo-mode ring-closing reaction of allenylazido derivatives under neutral conditions has been developed. The azabicyclo[m.n.0] compounds were prepared by applying this newly developed procedure. The seven-membered azacycle was prepared when the allene possessing an unsubstituted carboxyl amido functionality was submitted to the basic conditions. In addition, indole and quinoline skeletons were synthesized using this procedure. 相似文献