115-22-0Relevant articles and documents
Synthesis and characterization of ZrO2 as acid-basic catalysts: Reactivity of 2-methyl-3-butyn-2-ol
Aramendia, M. Angeles,Borau, Victoriano,Jimenez, Cesar,Marinas, Jose M.,Marinas, Alberto,Porras, Andres,Urbano, Francisco J.
, p. 240 - 250 (1999)
Two ZrO2-based catalysts have been synthesized by thermal treatment of a gel prepared from ZrOCl2 · 8H2O. The effect of different preparation parameters on the final properties of the solids was studied. Textural characterization was carried out from nitrogen adsorption/desorption isotherms. XRD and FT-Raman spectroscopy have been used to elucidate the physical state of the catalysts. Their acid-base properties were studied following temperature programmed desorption-mass spectrometry and diffuse reflectance infrared Fourier transform techniques, by using pyridine, 2,6-dimethylpyridine and carbon dioxide as probe molecules. Both solids were tested for the 2-methyl-3-butyn-2-ol reaction by using two different procedures: (a) in a microcatalytic pulse reactor and (b) through isotherm and temperature programmed surface reactions in a flow reactor. In addition, temperature programmed oxidation and temperature programmed desorption experiments revealed that catalyst deactivation was caused by carbon deposition on the catalytic surface. Amphoteric selectivity for both solids, leading to 3-hydroxy-3-methyl-2-butanone and 3-methyl-3-buten-2-one, depends on the reaction temperature; thus, it is 92% at 225°C for a catalyst calcined at 400°C (ZrO2-400VAC).
Hydrolysis of methylacetoin ethyl phosphate. competing pathways for carbonyl hydrate participation in a model for biotin carboxylation
Taylor, Scott D.,Kluger, Ronald
, p. 867 - 871 (1993)
Methylacetoin ethyl phosphate (1) is a phosphodiester with a carbonyl group β to phosphorus. The phosphate ester of a carbonyl hydrate, expected to be generated from an intramolecular reaction of 1 in base, is a model for an enzymic reaction intermediate which would form from the reaction of the tetrahedral addition production of biotin and bicarbonate with ATP. The hydrolysis of 1 is 104-105 times more rapid than that of dimethyl phosphate, extrapolated to common conditions (1 M NaOH, 55°C). Kinetic, product, and isotope labeling studies show that the hydrate of the carbonyl group of 1 serves as an intramolecular nucleophile toward phosphorus, forming the expected phosphate ester of the carbonyl hydrate through cyclic phosphorane intermediates. These adducts decompose by routes which parallel the proposed enzymic mechanism. In addition, solvent isotope incorporation reveals a route not found in reactions of carbonyl-substituted phosphotriesters: the conjugate base of the carbonyl hydrate acts an intramolecular nucleophile at the adjacent carbon atom, forming an unstable hydroxyoxirane (which becomes methylacetoin) and ethyl phosphate. An analogous reaction of ribonucleic acids (and RNAzymes) would have the 2′ hydroxyl group react at the 3′ carbon to form an oxyoxirane, cleaving the 3′ internucleotide bond.
Nonlinear optical chromophores based on Dewar's rules: Enhancement of electro-optic activity by introducing heteroatoms into the donor or bridge
Xu, Huajun,Yang, Dan,Liu, Fenggang,Fu, Mingkai,Bo, Shuhui,Liu, Xinhou,Cao, Yuan
, p. 29679 - 29688 (2015)
In this work, we investigated the enhancement of the electro-optic response by introducing electron-rich heteroatoms as additional donors into the donor or bridge of a conventional second-order nonlinear optical chromophore. A series of chromophores C2-C4 based on the same tricyanofuran acceptor (TCF) but with different heteroatoms in the alkylamino phenyl donor (C2 or C3) or thiophene bridge (C4) have been synthesized and systematically investigated. Density functional theory calculations suggested that chromophores C2-C4 had a smaller energy gap and larger first-order hyperpolarizability (β) than traditional chromophore C1 due to the additional heteroatoms. Single crystal structure analyses and optimized configurations indicate that the rationally introduced heteroatom group would bring larger β and weaker intermolecular interactions which were beneficial for translating molecular β into macro-electro-optic activity in electric field poled films. The electro-optic coefficient of poled films containing 25 wt% of these new chromophores doped in amorphous poly-carbonate afforded values of 83 and 91 pm V-1 at 1310 nm for chromophores C3 and C4, respectively, which are two times higher than that of the traditional chromophore C1 (39 pm V-1). High r33 values indicated that introducing heteroatoms to the donor and bridge of a conventional molecular structure can efficiently improve the electron-donating ability, which improves the β. The long-chain on the donor or bridge part, acting as the isolation group, may reduce inter-molecular electrostatic interactions, thus enhancing the macroscopic EO activity. These results, together with good solubility and compatibility with the polymer, show the new chromophore's potential application in electro-optic devices.
α-Oxidation of ketones using n-cation radicals
Schulz, Manfred,Kluge, Ralph,Sivilai, Li,Kamm, Birgit
, p. 2371 - 2380 (1990)
Six-membered ring ketones and acyclic ketones were oxidized by stable triarylamminium radical cations in moist acetonitrile at room temperature in the presence of a base to α-hydroxy ketones in good yield. Five-membered ring ketones gave the corresponding αβ-unsaturated compounds.
Boller,Whitfield
, p. 2773,2775 (1964)
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Chiu,S.K. et al.
, p. 61 - 65 (1978)
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A CO2-mediated base catalysis approach for the hydration of triple bonds in ionic liquids
Han, Buxing,Ke, Zhengang,Li, Ruipeng,Liu, Zhimin,Tang, Minhao,Wang, Yuepeng,Zeng, Wei,Zhang, Fengtao,Zhao, Yanfei
supporting information, p. 9870 - 9875 (2021/12/27)
Herein, we report a CO2-mediated base catalysis approach for the activation of triple bonds in ionic liquids (ILs) with anions that can chemically capture CO2 (e.g., azolate, phenolate, and acetate), which can achieve hydration of triple bonds to carbonyl chemicals. It is discovered that the anion-complexed CO2 could abstract one proton from proton resources (e.g., IL cation) and transfer it to the CN or CC bonds via a six-membered ring transition state, thus realizing their hydration. In particular, tetrabutylphosphonium 2-hydroxypyridine shows high efficiency for hydration of nitriles and CC bond-containing compounds under a CO2 atmosphere, affording a series of carbonyl compounds in excellent yields. This catalytic protocol is simple, green, and highly efficient and opens a new way to access carbonyl compounds via triple bond hydration under mild and metal-free conditions.
Thermodynamic favorable CO2 conversion via vicinal diols and propargylic alcohols: A metal-free catalytic method
Han, Li-Hua,Li, Jing-Yuan,Song, Qing-Wen,Zhang, Kan,Zhang, Qian-Xia,Sun, Xiao-Fang,Liu, Ping
supporting information, p. 341 - 344 (2019/07/04)
Organocatalysis represents a promising field in chemical fixation of CO2. Herein, a facile metal-free strategy was reported for the one-pot preparation of cyclic carbonates and α-hydroxy ketones from vicinal diols, propargylic alcohols and CO2. Wide scope of vicinal diols and propargylic alcohols was demonstrated to be efficient under the DBU-catalyzed conditions. A plausible mechanism was proposed, which included detailed main and side reactions under the metal-free conditions.