1502-22-3Relevant articles and documents
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Otsuji et al.
, p. 2124,2128 (1968)
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Reactivity of 1,3-dimethylimidazolium-2-carboxylate with dimethylcarbonate at high temperature: Unexpected 2-ethyl-functionalisation of the imidazolium moiety and employment of the NHC-CO2/dimethylcarbonate system in a base promoted reaction
Annese, Cosimo,D'Accolti, Lucia,Fusco, Caterina,Tommasi, Immacolata
, p. 94 - 97 (2014)
The reaction of 1,3-dimethylimidazolium-2-carboxylate and dimethylcarbonate (DMC) at high temperature yielded the new compounds 2-ethyl-1,3- dimethylimidazolium methyl carbonate salt and 2-ethyl-1,3-dimethylimidazolium-4- carboxylate zwitterion which were obtained as a mixture in approximately 4:1 molar ratio. The compounds were also isolated in pure form through alternative synthetic procedures and characterized by ESI-HRMS, 1H, 13C NMR and FTIR spectroscopy. The 1,3-dimethylimidazolium-2- carboxylate/dimethylcarbonate system was employed in the synthesis of 1,7-heptanedioic acid dimethyl ester from cyclohexanone and DMC. The target compound was obtained in 49% yield and 66% selectivity.
Intramolecular Cycloadditions of Ketenes and Keteniminium Salts to Olefins
Marko, Istvan,Ronsmans, Bruno,Hesbain-Frisque, Anne-Marie,Dumas, Stephane,Ghosez, Leon,et al.
, p. 2192 - 2194 (1985)
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Catalytic synthesis of 2-(1-cyclohexenyl)cyclohexanone by mixed heteropoly acids catalyst (PW12 + PMo12/SBA-15)
Wang, Ying-Ying,Wu, Bo,Liu, Chun-Li,Li, Fu-Xiang,Lv, Zhi-Ping,Xue, Jian-Wei
, p. 7343 - 7347 (2014)
Mixed heteropoly acids (phosphotungstic acid and phosphomolybdic acid) supported on SBA-15 (PW12 + PMo12/SBA-15) by impregnation method was used as catalysts of self-condensation reaction of cyclohexanone to synthesize the 2-(1-cyclohexenyl)cyclohexanone. The experimental results indicated that the mixed heteropoly acids supported on SBA-15 had effective catalytic performance, which catalytic synthesis of 2-(1-cyclohexenyl)cyclohexanone. The effects of various parameters on the conversion ratio such as the amount of catalyst, loading amount, reaction time and reaction temperature were investigated. The optimum reaction conditions were as follows: The loading of the PW12 + PMo12/SBA-15 was 29%, the percentage of catalyst in reactants was 3%, the reaction time was 2.5 h and the reaction temperature was 150°C. The conversion rate could reach 86.5%.
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.
Synthesis and catalytic properties of ZSM-5 zeolite with hierarchical pores prepared in the presence of n-hexyltrimethylammonium bromide
Bai, Peng,Wu, Pingping,Xing, Wei,Liu, Daolan,Zhao, Lianming,Wang, Youhe,Xu, Benjing,Yan, Zifeng,Zhao, Xiu Song
, p. 18586 - 18597 (2015/09/15)
ZSM-5 samples with hierarchical pores (macropores, mesopores and micropores) were synthesized in the presence of n-hexyltrimethylammonium bromide (HTAB) and tetrapropylammonium hydroxide (TPAOH). The effect of synthesis conditions including the Si/Al ratio, crystallization temperature and time, and the amount of HTAB added to the synthesis system on the final products was examined. The catalytic properties of the hierarchical zeolite were investigated in reactions of Claisen-Schmidt condensation of benzaldehyde and acetophenone, self-condensation of cyclohexanone and methanol conversion. The hierarchical zeolite exhibits superior catalytic performance in Claisen-Schmidt condensation of benzaldehyde and acetophenone and self-condensation of cyclohexanone and has a remarkably high selectivity for dimethyl ether in the methanol conversion reaction at relatively low temperatures, which was attributed to the fast mass transport in the three-dimensional hierarchical pore network. A cooperative assembly mechanism accounting for the formation of the hierarchical zeolite was proposed based on experimental results.
