A Practical, Water-Soluble, Ionic Scavenger for the Solution-Phase Syntheses of Amides
作者:Ming Lei、Xiao-Le Tao、Yan-Guang Wang
DOI:10.1002/hlca.200690056
日期:2006.3
A new ionic, water-soluble scavenger for acyl chlorides, 1-(2-aminoethyl)pyridinium bromide (1), has been investigated. Compound 1 was used for the rapid and simple purification of a series of benzamides and sulfonamides (Table) obtained by solution-phase synthesis from the corresponding amines (Scheme). The inexpensive scavenger, which can be prepared on large scale, was shown to readily ‘eliminate’
Zn-salen complexes with multiple hydrogen bonding donor and protic ammonium bromide: Bifunctional catalysts for CO2 fixation with epoxides at atmospheric pressure
作者:Xian-Dong Lang、Yi-Chen Yu、Liang-Nian He
DOI:10.1016/j.molcata.2016.04.018
日期:2016.8
sites on epoxideactivation (Lewis acidic zinc, phenolic hydroxyl group and protonated tertiary ammonium able to activateepoxide and bromide anion acting as a nucleophile), the easily-synthesized Zn-salen complexes showed outstanding performance at mild reaction conditions (CO2 0.1 MPa, 100 °C) using only 0.3 mol% catalyst amount. Besides, this protocol is applicable to a variety of epoxides including
The design of stable acid–basebifunctional heterogeneous catalysts has become crucial for efficient catalytic conversion of renewable biomass to high value-added chemicals. Heteropolyacids (HPAs) are of great interest due to their unique tunable structures and suitable acidity. In this study, a series of acid–basebifunctionalionic hybrid catalysts [MimAM]nH3−nPW12O40 (n = 1–3) were synthesized by
稳定的酸碱双功能多相催化剂的设计对于将可再生生物质高效催化转化为高附加值化学品至关重要。杂多酸(HPA)由于其独特的可调结构和适当的酸度而备受关注。在这项研究中,使用氨基官能化的咪唑鎓离子液体和H,通过离子交换法合成了一系列酸碱双官能离子杂化催化剂[MimAM] n H 3− n PW 12 O 40(n = 1–3)。3 PW 12 O 40作为前体。离子液体的引入导致[MimAM] n的Lewis-Brønsted酸度发生变化H 3- n PW 12 O 40。双酸性质的协同作用赋予[MimAM] H 2 PW 12 O 40更高的THF / H 2 O-NaCl葡萄糖脱水能力,HMF收率达53.9%。为了理解有效的多相催化作用,提出了一种独特的顺序氢转移机理。其中,由于OH和O之间存在有效的氢键,葡萄糖脱水中不存在果糖和左旋葡糖酮的原因可能是稳定的中间体1,2-烯二醇和脱水糖的形成。
Schiff Base Structured Acid-Base Cooperative Dual Sites in an Ionic Solid Catalyst Lead to Efficient Heterogeneous Knoevenagel Condensations
cyanoacetate, it exhibits a conversion of 95.8 % and a selectivity of 100 %; the conversion is even much higher than that (78.2 %) with ethanol as a solvent. The solid catalyst has a convenient recoverability with only a slight decrease in conversion following subsequent recyclings. Furthermore, the new catalyst is highly applicable to many substrates of aromatic aldehydes with activated methylene compounds
The dispersion of carbon nanotubes in water with the aid of very small amounts of ionic liquid
作者:Xiaosi Zhou、Tianbin Wu、Kunlun Ding、Baoji Hu、Minqiang Hou、Buxing Han
DOI:10.1039/b900849g
日期:——
Multiwalled carbon nanotubes can be dispersed stably in water with the aid of a verysmallamount of 1-aminoethyl-3-methylimidazolium bromide ([C(2)NH(2)mim][Br]) or 1-(2-aminoethyl) pyridinium bromide ([C(2)NH(2)py][Br]).