24344-21-6Relevant academic research and scientific papers
The influence of the preparation method on the physico-chemical properties and catalytic activities of ce-modified ldh structures used as catalysts in condensation reactions
Birjega, Ruxandra,Breze?tean, Ioana,Dumitru, Marius,Marcu, Ioan-Cezar,Matei, Andreea,Osiac, Mariana,Pavel, Octavian Dumitru,Stamate, Alexandra-Elisabeta,Z?voianu, Rodica
, (2021/10/25)
Mechanical activation and mechanochemical reactions are the subjects of mechanochem-istry, a special branch of chemistry studied intensively since the 19th century. Herein, we comparably describe two synthesis methods used to obtain the following layered double hydroxide doped with cerium, Mg3 Al0.75 Ce0.25 (OH)8 (CO3)0.5·2H2 O: the mechanochemical route and the co-precipitation method, respectively. The influence of the preparation method on the physico-chemical properties as determined by multiple techniques such as XRD, SEM, EDS, XPS, DRIFT, RAMAN, DR-UV-VIS, ba-sicity, acidity, real/bulk densities, and BET measurements was also analyzed. The obtained samples, abbreviated HTCe-PP (prepared by co-precipitation) and HTCe-MC (prepared by mechanochemical method), and their corresponding mixed oxides, Ce-PP (resulting from HTCe-PP) and Ce-MC (result-ing from HTCe-MC), were used as base catalysts in the self-condensation reaction of cyclohexanone and two Claisen–Schmidt condensations, which involve the reaction between an aromatic aldehyde and a ketone, at different molar ratios to synthesize compounds with significant biologic activity from the flavonoid family, namely chalcone (1,3-diphenyl-2-propen-1-one) and flavone (2-phenyl-4H-1benzoxiran-4-one). The mechanochemical route was shown to have indisputable advantages over the co-precipitation method for both the catalytic activity of the solids and the costs.
Highly selective self-condensation of cyclic ketones using MOF-encapsulating phosphotungstic acid for renewable high-density fuel
Deng, Qiang,Nie, Genkuo,Pan, Lun,Zou, Ji-Jun,Zhang, Xiangwen,Wang, Li
supporting information, p. 4473 - 4481 (2015/08/11)
Transferring biomass-derived cyclic ketones such as cyclopentanone and cyclohexanone to a mono-condensed product through aldol self-condensation has great potential for the synthesis of a renewable high-density fuel. However, the selectivity is low for numerous catalysts due to the rapid formation of di-condensed by products. Herein, MIL-101-encapsulating phosphotungstic acid is synthesized to catalyze the self-condensation with selectivity of more than 95%. PTA clusters are uniformly dispersed in MOF cages and decrease the empty space (pore size), which provides both acidic sites and shape-selective capability. The optimal PTA amount decreases corresponding to the increase of reactant size. The shape-selectivity is also realized by changing the pore size of MOF such as from MIL-101 to MIL-100. Moreover, the catalyst is resistant to PTA leaching and performs stably after 5 runs. After hydrodeoxygenation of the mono-condensed product, high-density biofuels with densities of 0.867 g ml-1 and 0.887 g ml-1 were obtained from cyclopentanone and cyclohexanone, respectively. This study not only provides a promising route for the production of high-density biofuel but also suggests the advantage of MOF-based catalysts for shape-selective catalysis involving large molecular size.
METHOD FOR THE PRODUCTION OF 4,4'-[1-TRIFLUOROMETHYL)ALKYLIDENE]-BIS-(2,6-DIPHENYLPHENOLS)
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Page/Page column 9, (2010/12/29)
The present invention relates to a process for preparing 4,4′-[1-(trifluoromethyl)alkylidene]bis(2,6-diphenylphenols), in particular for preparing 4,4′-[1-(trifluoromethyl)ethylidene]bis(2,6-diphenylphenol), which comprises the self-condensation of cyclohexanone in the presence of a basic catalyst to form tricyclic condensation products, dehydrogenation of the resulting tricyclic condensation products in the presence of a supported transition metal catalyst in the condensed phase to form 2,6-diphenylphenol and reaction of the 2,6-diphenylphenol with a trifluoromethyl ketone. The invention further provides an improved process for preparing 2,6-diphenylphenol by aldol self-condensation of cyclohexanone.
Deoxygenation and Desulfurization of Organic Compounds via Transition Metal Atom Cocondensation
Togashi, Shigeo,Fulcher, John G.,Cho, Bong Rae,Hasegawa, Minoru,Gladysz, J.A.
, p. 3044 - 3053 (2007/10/02)
Reactions resulting from the cocondensation of transition metal atoms with a variety of oxygen- and sulfur-containing organic compounds are surveyed.Alkenes are the major or exclusive volatile products when epoxides are reacted with Ti, V, Cr, Co, and Ni atoms. 2,6-Dimethylpyridine-N-oxide and dimethyl sulfoxide undergo deoxygenation upon cocondensation with chromium, but diisopropyl ether and decyl methyl ether do not.Dibenzyl ether yields bis(η6-dibenzyl ether)chromium(0) with Cr atoms, but dibenzyl sulfide undergoes desulfurization.Cyclohexanone and cycloheptanone afford low yields of reductive coupling and aldol products when cocondensed with Cr, Co, and Ni atoms.Nitro- and nitrosoarenes are deoxygenated to coupled azo and azoxy products with Cr atoms.Carbazole (3) is obtained from 2-nitrosobiphenyl, implicating nitrene or nitrenoid intermediates.Whereas isocyanides are not formed from isocyanates and metal atoms, they are produced when isothiocyanates are cocondensed with Cr and V atoms.
