565-61-7Relevant academic research and scientific papers
Systematic Engineering of Single Substitution in Zirconium Metal-Organic Frameworks toward High-Performance Catalysis
Huang, Ning,Yuan, Shuai,Drake, Hannah,Yang, Xinyu,Pang, Jiandong,Qin, Junsheng,Li, Jialuo,Zhang, Yingmu,Wang, Qi,Jiang, Donglin,Zhou, Hong-Cai
supporting information, p. 18590 - 18597 (2017/12/15)
Zirconium-based metal-organic frameworks (Zr-MOFs) exhibit great structural tunability and outstanding chemical stability, rendering them promising candidates for a wide range of practical applications. In this work, we synthesized a series of isostructural PCN-224 analogues functionalized by ethyl, bromo, chloro, and fluoro groups on the porphyrin unit, which allowed us to explicitly study the effects of electron-donating and electron-withdrawing substituents on catalytic performance in MOFs. Owing to the different electronic properties of ethyl, bromo, chloro, and fluoro substitutes, the molecular-level control over the chemical environment surrounding a catalytic center could be readily achieved in our MOFs. To investigate the effects of these substitutes on catalytic activity and selectivity, the oxidation of 3-methylpentane to corresponding alcohols and ketones was utilized as a model reaction. Within these five analogues of PCN-224, an extremely high turnover number of 7680 and turnover frequency of 10 240 h-1 was achieved by simply altering the substitutes on porphyrin rings. Moreover, a remarkable 99% selectivity of the tertiary alcohol over the five other possible by-products are realized. We demonstrate that this strategy can be used to efficiently screen a suitable peripheral environment around catalytic cores in MOFs for catalysis.
Photooxygenation of alkanes by dioxygen with: P -benzoquinone derivatives with high quantum yields
Ohkubo, Kei,Hirose, Kensaku,Fukuzumi, Shunichi
, p. 731 - 734 (2016/07/06)
Alkanes were oxygenated by dioxygen with p-benzoquinone derivatives such as p-xyloquinone in alkanes which are used as solvents to yield the corresponding alkyl hydroperoxides, alcohols and ketones under visible light irradiation with high quantum yields (Φ = 1000, 1600%). The photooxygenation is started by hydrogen atom abstraction from alkanes by the triplet excited states of p-benzoquinone derivatives as revealed by laser-induced transient absorption spectral measurements.
Solvent-Free Photooxidation of Alkanes by Dioxygen with 2,3-Dichloro-5,6-dicyano-p-benzoquinone via Photoinduced Electron Transfer
Ohkubo, Kei,Hirose, Kensaku,Fukuzumi, Shunichi
supporting information, p. 2255 - 2259 (2016/08/30)
Photooxidation of alkanes by dioxygen occurred under visible light irradiation of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) which acts as a super photooxidant. Solvent-free hydroxylation of cyclohexane and alkanes is initiated by electron transfer from alkanes to the singlet and triplet excited states of DDQ to afford the corresponding radical cations and DDQ??, as revealed by femtosecond laser-induced transient absorption measurements. Alkane radical cations readily deprotonate to produce alkyl radicals, which react with dioxygen to afford alkylperoxyl radicals. Alkylperoxyl radicals abstract hydrogen atoms from alkanes to yield alkyl hydroperoxides, accompanied by regeneration of alkyl radicals to constitute the radical chain reactions, so called autoxidation. The radical chain is terminated in the bimolecular reactions of alkylperoxyl radicals to yield the corresponding alcohols and ketones. DDQ??, produced by the photoinduced electron transfer from alkanes to the excited state of DDQ, disproportionates with protons to yield DDQH2.
5-SEC-BUTYL-2-(2,4-DIMETHYL-CYCLOHEX-3-ENYL)-5-METHYL-[1,3]DIOXANE AND PROCESS FOR MAKING THE SAME
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Paragraph 0012; 0013, (2014/04/03)
The present invention is directed to 5-sec-butyl-2-(2,4-dimethyl-cyclohex-3-enyl)-5-methyl-[1,3]dioxane and a novel process for making the same.
5-sec-butyl-2-(2,4-dimethyl-cyclohex-3-enyl)-5-methyl-[1,3]dioxane and process for making the same
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Paragraph 0013, (2014/04/03)
The present invention is directed to 5-sec-butyl-2-(2,4-dimethyl-cyclohex-3-enyl)-5-methyl-[1,3]dioxane and a novel process for making the same.
Highly efficient redox isomerization of allylic alcohols and transfer hydrogenation of ketones and aldehydes catalyzed by ruthenium complexes
Liu, Pei Nian,Ju, Kun Dong,Lau, Chak Po
supporting information; experimental part, p. 275 - 280 (2011/04/16)
A dicationic dichloro-bipyridine-ruthenium complex shows very high catalytic activity in redox isomerization of allylic alcohols but a relatively low one in transfer hydrogenation of ketones; surprisingly, the analogous dimethyl-bipyridine-ruthenium complex shows reverse catalytic activities in the two reactions.
Efficient and selective Al-catalyzed alcohol oxidation via oppenauer chemistry
Graves, Christopher R.,Zeng, Bi-Shun,Nguyen, SonBinh T.
, p. 12596 - 12597 (2008/02/03)
A highly active and selective Al-based catalytic Oppenauer (O) oxidation is reported. Quantitative and selective oxidations of a variety of benzylic, propargylic, allylic, and aliphatic primary and secondary alcohols were achieved using nitrobenzaldehyde derivatives as the oxidant and simple aluminum compounds as precatalysts. Copyright
FeCl3-activated oxidation of alkanes by [Os(N)O 3]-
Yiu, Shek-Man,Wu, Zhi-Biao,Mak, Chi-Keung,Lau, Tai-Chu
, p. 14921 - 14929 (2007/10/03)
Although the ion [OsVIII(N)(O)3]- is a stable species and is not known to act as an oxidant for organic substrates, it is readily activated by FeCl3 in CH2Cl2/CH 3CO2H to oxidize alkanes efficiently at room temperature. The oxidation can be made catalytic by using 2,6-dichloropyridine N-oxide as the terminal oxidant. The active intermediates in stoichiometric and catalytic oxidation are proposed to be [(O)3OsVIII≡N-Fe III] and [Cl4(O)OsVIII≡N-Fe III], respectively.
H-atom abstraction from selected C-H bonds in 2,3-dimethylpentanal, 1,4-cyclohexadiene, and 1,3,5-cycloheptatriene
Tuazon, Ernesto C.,Aschmann, Sara M.,Nguyen, Marie V.,Atkinson, Roger
, p. 415 - 426 (2007/10/03)
The gas-phase reactions of OH radicals with 1,4-cyclohexadiene, 1,3,5-cycloheptatriene, and 2,3-dimethylpentanal have been investigated to determine the importance of H-atom abstraction at specific positions in these molecules. Benzene was observed as a product of the reaction of OH radicals with 1,4-cyclohexadiene in 12.5 ± 1.2% yield, in good agreement with a previous study and indicating that this is the fraction of the reaction proceeding by H-atom abstraction from the allylic C-H bonds. In contrast, no formation of tropone from 1,3,5-cycloheptatriene was observed, suggesting that in this case H-atom abstraction is not important. For the reaction of OH radicals with 2,3-dimethylpentanal, formation of 3-methyl-2-pentanone was observed in 5.4 ± 1.0% yield (after correction for reaction of 3-methyl-2-pentanone with OH radicals), and this product is predicted to be formed after initial H-atom abstraction from the 2-position CH group. Acetaldehyde and 2-butanone were also observed as products, with initial yields of ～90% and ～26%, respectively, and their formation appeared to involve, at least in part, an intermediary acyl peroxy radical. Using a relative rate method, the measured rate constants for the reactions of OH radicals with 2,3-dimethylpentanal, 3-methyl-2-pentanone, and tropone are (in units of 10-12 cm3 molecule-1 s-1) 2,3-dimethylpentanal, 42 ± 7; 3-methyl-2-pentanone, 6.87 ± 0.08; and tropone, 42 ± 6.
Unfunctionalized, α-epimerizable nonracemic ketones and aldehydes can be accessed by crystallization-induced dynamic resolution of imines
Kosmrlj, Janez,Weigel, Leland O.,Evans, David A.,Downey, C. Wade,Wu, Jimmy
, p. 3208 - 3209 (2007/10/03)
This paper describes an operationally simple deracemization process of aldehydes and ketones. This new crystallization-induced dynamic resolution (CIDR) protocol allows for nearly complete conversion of the racemic mixture into one enantiomer. Crystallization of imines derived from racemic ketones or aldehydes 1 and trans-(1R,2R)-1-amino-6-nitroindan-2-ol (2) afforded diastereomerically pure, crystalline imines 3. Biphasic hydrolysis of 3 then affords recovered 2 and enantiomerically enriched 1 in high yield and er (substrate, yield/ee: 2-methylcyclohexanone, 97%/92; 2-ethylhexanal, 94%/98; 2-methylcyclopentanone, 94%/98; 2-cyclohexylcyclohexanone, ND/98; 3-methyl-2-pentanone, ND/76). The scope, limitations, and industrial perspective of this process are discussed. This highly effective CIDR process is likely due to π-stacking of 2 and a hydrogen bonding of the imine with the free hydroxyl of 2 in the solid state. Copyright
