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Interfacial Catalysis at Oil/Water Interfaces
Published in Alexander G. Vdlkdv, Interfacial Catalysis, 2002
The applications of PTC in polymerization are gradually increasing. Tagle and coworkers [17,18] synthesized poly(amide ester)s from diphenols with the amide group in the side chain, using PT catalysts such as benzyltriethylammonium chloride, with good results. The use of anhydrous potassium carbonate as the base is to promote the organic reaction under solid-liquid PTC. Albanese et al. [19] described some recent applications in this area, and the reactions of aza anions with 2-bromocarboxylic esters and expoxides afforded protected α-amino acids and β-amido alcohols. Sirovski [20] described some examples of PTC applications in organochlorine chemistry. Using a polymeric crown ether the results of m-phenoxytoluene chlorination are also reported. Carboxylic acids and picric acid act as inhibitors, while benzyl alcohol behaves as a strong promoter. In the absence of the promoter, the reaction is conducted either at the interface or in the third phase that is a border liquid film between the organic and aqueous phases.
Pyridine-bridged cobalt tetra-aminophthalocyanine to active peroxymonosulphate for efficient degrading carbamazepine
Published in Environmental Technology, 2023
Zhiguo Shang, Zhexin Zhu, Gangqiang Wang, Wangyang Lu, Bingyao Wu, Qijian Li
To further evaluate the chemical structure, the XPS of CoTAPc and CoTAPc-TINA have been performed, as given in Figure 2. According to Figure 2(a), within the N1s spectrum of CoTAPc, the peak at 398.79 eV belongs to aza-bridging and pyrrole nitrogen molecules, and the N1s space centred at 399.83 eV is attributed to the nitrogen of the amino substituent on the CoTAPc outside ring [30]. The narrow spectrum of CoTAPc-TINA (Figure 2b) shows the aza-bridging and pyrrole nitrogen atoms at 398.48 eV. For CoTAPc-TINA, compared with CoTAPc, the binding energies of aza-bridging and pyrrole nitrogen atoms were reduced, which may be ascribed to the electron-giving effect of the pyridine group. Peaks at 399.90 and 402.15 eV are attributed to pyridine ring and amide group nitrogen atoms, respectively [26,31].
Recent Progress on the Structure-Performance Relationship between Diglycolamide Extractants and f-Elements
Published in Solvent Extraction and Ion Exchange, 2022
Zhibin Liu, Huibo Li, Yaoyang Liu, Chuang Zhao, Caishan Jiao, Yu Zhou, Meng Zhang, Yang Gao
Bhattacharyya et al.[65–67] reported two multi-DGA ligands where the DGA arms are tethered to the nitrogen atoms of two aza-crown ether scaffolds, a 9-membered aza-crown ether containing three ‘N’ atoms (T9C3ODGA) and a 12-membered aza-crown ether containing four ‘N’ atoms (T12C4ODGA) as shown in Figure 10. The extraction performance of T9C3ODGA towards trivalent f-elements such as Am(III) and Eu(III) is significantly better than previously studied tripodal DGAs such as T-DGA and TREN-DGA. The phenomenon occurs because there exist less stereochemical constrains in the T9C3ODGA complexes as the three DGA arms rest on the macrocyclic ring, while the DGA moieties are bound to a single atom at the center for T-DGA or TREN-DGA. Eu(III) is preferentially extracted over Am(III), which is verified by more negative interaction energy of Eu(III) complex than that of Am(III) complex both in the gas and solution phases.[22] The extraction efficiency of T12C4ODGA for Am(III) and Eu(III) is even higher than T9C3ODGA. Similarly to T9C3ODGA, T12C4ODGA shows higher extraction for Eu(III) than Am(III). Interestingly, the separation factor SFEu/Am values are almost constant at varying aqueous phase nitric acid concentration of 0–6 M.[67]
Synthesis of six- and seven-membered and larger heterocylces using Au and Ag catalysts
Published in Inorganic and Nano-Metal Chemistry, 2018
An azepinoindole PPARγ agonist was constructed involving a reaction of indole and tethered alkyne to synthesize 7-membered N-heterocycle in the presence of gold catalyst. Good yield (68%) of 7-membered heterocycle was obtained from nosyl-tryptamine alkyne with (acetonitrile)[(2-biphenyl)di-tert-butylphosphine]gold(I) hexafluoroantimonate in dichloromethane.[17,18] The 2-nitrobenzenesulfonyl protecting group was cleaved under basic conditions using thiophenol after isolation of the azepinoindole.[19–21] The aromatic tail was tethered from the secondary amine of the indole (over 2 steps in 31% yield) by aza-Michael addition with 2-pyridine acrylamide. The indole-nitrogen under aza-Michael addition with methyl acrylate installed a masked carboxylic acid. The formed product was not separated from un-reacted substrate. The less polar butyl acrylate was utilized for the functionalization of indole-nitrogen to allow efficient separation. However, aza-Michael addition not afforded useful yield of amide as in the case of indoloazocine PPARγ agonist (Scheme 15). The carboxylic acid was not synthesized successfully as gold catalysts are expensive.