54889-48-4Relevant articles and documents
Oxidative esterification of aliphatic aldehydes and alcohols with ethanol over gold nanoparticle catalysts in batch and continuous flow reactors
Taketoshi,Ishida,Murayama, Toru,Honma, Tetsuo,Haruta, Masatake
, (2019/08/26)
Selective esterification of aliphatic aldehydes and alcohols with ethanol in the absence of a base is a more difficult reaction than that with methanol. Gold nanoparticles on ZnO were found to catalyze the oxidative esterification of octanal to ethyl octanoate with high selectivity. In addition, it was found that Au/ZnO was the most effective catalyst for yielding the desired ethyl ester without a base by direct esterification of 1-octanol with ethanol. As far as we know, this is the first report on oxidative esterification to give aliphatic ethyl esters from less reactive aliphatic alcohols and aldehydes without a base. The optimal size of gold NPs ranged from 2 to 6 nm and the presence of Au(0) was indispensable for this reaction. Au/ZnO exhibited the highest catalytic activity in both batch and flow reactors. The conversion was maintained for more than 20 h with 95% selectivity to the desired ethyl ester in the flow system.
Facile synthesis of Cu3(BTC)2/cellulose acetate mixed matrix membranes and their catalytic applications in continuous flow process
Hou, Junying,Luan, Yi,Huang, Xiubing,Gao, Hongyi,Yang, Mu,Lu, Yunfeng
, p. 9123 - 9129 (2017/08/29)
Metal-organic framework (MOF)-based mixed matrix membranes (MMMs) were fabricated by a combination of Cu3(BTC)2 MOF and polymer cellulose acetate. The cellulose acetate in the MMMs served as the matrix and the Cu3(BTC)2 MOF as the filler. The as-synthesized MMMs were utilized as a heterogeneous catalyst for aldehyde acetalization. The characterization techniques indicated that the Cu3(BTC)2 crystals were uniformly dispersed in the MMMs. The BET surface area of the Cu3(BTC)2-based MMM was measured to be 459 m2 g-1 at 60 wt% Cu3(BTC)2 loading. Furthermore, the MMMs served as an excellent catalyst under our continuous flow catalytic reaction conditions. The optimal catalytic result of benzaldehyde yield reached 94% with 60 wt% Cu3(BTC)2 loading of the MMMs at room temperature and the benzaldehyde diethyl acetal reached 0.59 mmol min-1 gCu-BTC-1.
Hexameric resorcinarene capsule is a bronsted acid: Investigation and application to synthesis and catalysis
Zhang, Qi,Tiefenbacher, Konrad
supporting information, p. 16213 - 16219 (2013/11/19)
Molecular capsules have attracted interest as simple enzyme mimetics and several examples of catalytic transformations in water-soluble metal-ligand based systems have been reported. This is not the case for hydrogen-bond based molecular capsules, which in contrast can be employed in organic solvents. We describe herein our investigations of such a system: The resorcin[4]arene hexamer is one of the largest hydrogen bond-based self-assembled capsules and has been studied intensively due to its ready availability. We present evidence that the capsule acts as a reasonably strong Bronsted acid (pK a approximately 5.5-6). This finding explains the capsule's high affinity toward tertiary amines that are protonated and therefore encounter cation-π interactions inside the cavity. We were able to translate this finding into a first synthetic application: A highly substrate-selective Wittig reaction. We also report that this property renders the capsule an efficient enzyme-like catalyst for substrate selective diethyl acetal hydrolysis.
