By ligand, TEMPO, and base screening, we developed a mild and green one-pot imine synthesis from alcohols and amines via a low-loading palladium-catalyzed tandem aerobic alcohol oxidation-dehydrative condensation reaction that can be readily carried out in open air at room temperature.
Direct imine formation by oxidative coupling of alcohols and amines using supported manganese oxides under an air atmosphere
作者:Bo Chen、Jun Li、Wen Dai、Lianyue Wang、Shuang Gao
DOI:10.1039/c4gc00336e
日期:——
Manganese oxides loaded on various supports have been prepared and studied for the direct imine formation by oxidative coupling of alcohols and amines. Among the catalysts, hydroxyapatite supported manganese oxides (MnOx/HAP) show the best activity and selectivity for this reaction in the absence of an additional base using air as the environmentally benign terminal oxidant. NH3-/CO2-TPD results show
已经制备了负载在各种载体上的锰氧化物,并研究了通过醇和胺的氧化偶联直接形成亚胺的方法。在这些催化剂中,羟基磷灰石负载的锰氧化物(MnO x / HAP)在没有使用空气作为环境友好的终端氧化剂的附加碱的情况下,对于该反应表现出最佳的活性和选择性。NH 3- / CO 2 -TPD结果表明,MnO x的两性性质/ HAP对于该反应获得令人满意的收率至关重要。各种芳族醇和胺均以良好或优异的收率平稳地转化为相应的亚胺。该催化剂可重复使用,并且在所有9次重复使用测试中均可提供98%的产品收率。与新鲜催化剂相比,经过九次反应后,再活化的MnO x / HAP的XRD和SEM没有明显变化。
3%Pt/D-TiO2/Ti3C2 showed excellent activity and chemoselectivity to N-alkyl amines in the presence of base additive K3PO4 undervisible-lightirradiation; interestingly the chemoselectivity almost completely switched to N-benzylideneanilines in the presence of base additive KOH. In comparison, Pt nanoparticles on S and N co-doped TiO2 prepared from titanium carbide (3%Pt/D-TiO2@C) showed sharply decreased activity
可见光诱导的一锅、多步和化学选择性可调反应突出了经济、可持续和绿色的过程。在此,我们报道了分散在 S 和 N 共掺杂二氧化钛/碳化钛 (MXene) (3%Pt/D-TiO 2 /Ti 3 C 2 ) 异质结上的 Pt 纳米粒子作为芳香硝基化合物和醇之间串联反应的光催化剂生产N-烷基化产品。通过在Ti 3 C 2纳米片上原位生长TiO 2制备3%Pt/D-TiO 2 /Ti 3 C 2异质结,S和N共掺杂TiO 2用硫脲,然后是平均直径为 2.9 nm 的 Pt 纳米颗粒,很好地分散在 D-TiO 2 /Ti 3 C 2 上。3%Pt/D-TiO 2 /Ti 3 C 2在可见光照射下,在碱性添加剂K 3 PO 4存在下对N-烷基胺表现出优异的活性和化学选择性;有趣的是,在碱添加剂 KOH 存在下,化学选择性几乎完全转换为N-亚苄基苯胺。相比较而言,在S和的Pt纳米颗粒N共掺杂TiO 2从碳化钛(3%的Pt