共查询到20条相似文献,搜索用时 15 毫秒
1.
The scope of the serendipitous reductive monoalkylation of ethyl (4-methoxy-3-nitrophenyl) acetate taking place during reduction of the nitro functionality to the corresponding primary amine when treated with hydrogen (1 atm) over Pd/C (10%) in ethanol is investigated. Upon prolonged reaction time the reaction conducted in ethanol and methanol yields significant amount of the corresponding secondary amines, while when performed in n-butanol and i-propanol it only resulted in the formation of a small amount of the corresponding secondary amines. Further development of the reductive monoalkylation reaction provided conditions that facilitate conversion of a range of different nitro aryls in one-pot to the corresponding secondary benzyl amino aryls in mostly good to excellent yields. This is accomplished by using hydrogen (1 atm) over Pd/C (10%) as reducing agent and benzaldehyde as the benzyl source combined with a stepwise reaction sequence. This chemistry was further extended to the formation of substituted benzyl amino aryls. The yields of the latter products varied dramatically depending on the substitution patterns associated with the benzaldehyde. However, by altering the reaction conditions it was possible to improve the yields of the benzylated products. 相似文献
2.
A range of different nitrophenol derivatives were converted in one‐pot to the corresponding secondary alkyl aminophenols in good to excellent yields by using ketones as alkyl source and hydrogen over 10 wt% Pd/C as reducing agent. In all examples, except for one, the secondary amine was the sole alkylation product isolated. When aldehydes were used as alkyl source, the corresponding tertiary amine as a sole alkylation product was isolated. 相似文献
3.
A new highly efficient one-pot derivatization of medicinally important 9-aminoacridines (9-AA) at the amine position is described. Simple reductive amination and SNAr reaction using easily accessible starting materials give a fast entry to novel 9-AA derivatives for biological screening. 相似文献
4.
Pedro J. Llabres-Campaner Patricia Woodbridge-Ortega Rafael Ballesteros-Garrido Rafael Ballesteros Belén Abarca 《Tetrahedron letters》2017,58(52):4880-4882
A borrowing hydrogen reaction with different diols was employed for the preparation of complex beta- gamma- or epsilon-amino alcohols from p-toluidine and tetrahydroquinoline with the aim of better understanding the applicability of the Pd/C ZnO heterogeneous catalyst. 相似文献
5.
Jadwiga Skupiska Monika Karpiska Leszek Wachowski Magdalena Hofman 《Reaction Kinetics and Catalysis Letters》2004,82(2):311-316
A simple catalytic system containing metallic palladium, iron and iodine has been shown to be very active in the carbonylation
of nitrobenzene to carbamate. The influence of the components of the catalytic system studied on its selectivity and activity
has been established. It has been found that the catalytic activity of palladium supported on carbon (using both lignite coal
and bituminous coal) was not lower than the activity of metallic palladium.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
6.
采用TiO2上高度分散的金纳米粒子做催化剂,从脂肪族硝基化合物、醛和氢气可高选择性合成硝酮。与碳负载Pt催化剂相比,该催化体系上硝酮的选择性从50%增加到90%。其催化性能可有活性位结构、载体特性和反应条件精确调节。 相似文献
7.
8.
在H2O-alcohol体系中通过Pd/C催化的还原偶联反应由杂环芳卤高收率的得到了二芳基化合物. 该方法操作简单, 环境友好, Pd/C可重复使用, 无需相转移催化剂也能得到较高收率. 讨论了醇、碱的种类和用量以及不同底物对反应收率的影响. 相似文献
9.
部分中毒Pd/C催化剂上环戊二烯的加氢反应 总被引:3,自引:0,他引:3
用固定床反应器考察了Pd/C催化剂硫化前后环戊二烯的加氢性能,Pd/C催化剂经硫化后,生成环戊烯的得率由75%上升到97%。确定了最佳硫化条件。应用微型脉冲反应器和程序升温表面反应(TPSR)研究了硫化特性,发现硫在Pd/C催化剂在存在着两种吸附状态,吸附在对应于TPSR中低温峰位上的硫不影响加氢反应活性,吸附在对应于高温峰位上的硫引起催化剂催化活性下降。 相似文献
10.
XinHuaXU‘ HongYiZHOU DaHuiWANG 《中国化学快报》2003,14(7):700-703
Chlorobenzene was dechlorinated by Pd/Fe bimetallic system in water through catalytic reduction. The dechlorination rate increases with increase of bulk loading of Pd due to the increase of both the surface loading of the Pd and the total surface area. For conditions with 0.005% Pd/Fe, 45% dechlorination efficiency was achieved within 5 h. The dechlorinated reaction is believed to take place on the bimetal surface in a pseudo-first-order reaction, with the rate constant being 0.0043 min^-1. 相似文献
11.
12.
13.
14.
15.
We report an alternative hydrogenation of aromatic aminoketones by heterogeneous catalyst of palladium on carbon (Pd/C) in which nitro, in particular carbonyl groups in the ketones, could be selectively transformed to corresponding amino ketone, secondary alcohol, or methylene compound. 相似文献
16.
钯/炭催化剂在不同气氛中热处理的考察 总被引:1,自引:0,他引:1
贵金属钯/炭催化剂(Pd/C)在石油化工和精细化工中有着广泛的用途,受到人们的普遍重视。作者成功地研制出一种性能优良的Pd/C,已用于药物和香料生产过程中的加氢反应。制备Pd/C的过程表明,影响其加氢活性的因素比较复杂,热处理就是其中重要的一环。本文总结了含水55%的Pd/C催化剂在不同气氛中进行热处理后对苯乙烯加氢活性的影响。另外,通过热差法(DTA)和光电子能谱(XPS)考察了Pd/C在加热过程 相似文献
17.
George N. KarageorgeJohn E. Macor 《Tetrahedron letters》2011,52(40):5117-5119
Formation of N-alkylated α-methyltryptamine derivatives (2) was accomplished by simple reductive amination of amine (1) with ketones using catalytic hydrogenation conditions (3 atm H2 and 10% Pd on carbon). This method was also applied to other primary and secondary amines using ketones and aldehydes. 相似文献
18.
Wen Qiang Du Ze Ming Rong Yan Liang Yong Wang Xin Yi Lu Yi Fan Wang Lian Hai Lu 《中国化学快报》2012,23(7):773-776
Selective hydrogenation of α, β-unsaturated aldehydes with modified Pd/C catalyst was developed.The reduction of C=O bond could be efficiently inhibited by the addition of carbonates,and high selectivity to the corresponding saturated aldehydes was achieved under mild conditions.This protocol provides an alternative for efficient preparation of saturated aldehydes. 相似文献
19.
20.
CO2电化学还原反应可以将CO2转化为燃料并同时实现再生能源的有效存储. 目前纳米结构的多相催化剂已经广泛应用于此反应,其中碳负载钯纳米粒子(Pd/C)表现出优异的CO2电化学还原性能. 本工作研究了钯载量对于Pd/C催化剂结构以及其催化CO2还原生成CO反应活性和选择性的影响. 不同载量的Pd/C催化剂通过液相还原方法制备,钯纳米粒子均匀地分散在碳载体上,载量并没有明显改变对纳米粒子的粒径. 在优选的电解质(0.1 mol·L-1 KHCO3)中,CO法拉第效率与载量呈现火山型曲线关系,-0.89 V时载量为20wt%的Pd/C催化剂达到最高的CO法拉第效率(91.2%). 生成CO的几何电流密度随着钯载量的增加而增加,但CO转换频率具有相反的趋势,载量为2.5wt%的Pd/C催化剂具有最高的转换频率. 这种载量对CO2电化学还原反应活性和选择性的影响主要由活性位的数量、反应动力学、中间物种的稳定性以及反应物、中间物种和产物的传质过程等共同决定. 相似文献