34468-07-0Relevant articles and documents
Microcalorimetric investigation of mordenite and Y zeolites for 1-methylnaphthalene isomerisation
Ferino,Monaci,Rombi,Solinas
, p. 2647 - 2652 (1998)
Adsorption microcalorimetry of pyridine has been used to determine the concentration and the distribution of strengths of the acid sites of Y zeolites and mordenite samples. 1-Methylnaphthalene was reacted over these samples at 623 K under atmospheric pressure in a continuous-flow fixed-bed reactor. For Y zeolites the relative extents of 1-methylnaphthalene isomerisation and disproportionation have been found to depend on the density of the acid sites. Coke growth favours isomerisation over disproportionation as time-on-stream increases. However, both disproportionation and coking are highly disfavoured in the channel system of mordenites, in spite of the relatively high density of the acid sites. The accumulation of strongly adsorbed feed and/or product molecules is responsible for the severe decay in activity of non-dealuminated mordenite.
Molybdenum-mediated cyclocarbonylation of 1-ethynyl-2-allenylbenzenes to 1H-cyclopenta[a]inden-2-ones
Datta, Swarup,Liu, Rai-Shung
, p. 7985 - 7988 (2005)
Although 1-ethynyl-2-allenylbenzenes readily undergo Myers-Saito or Schmittel cyclization under mild conditions, cyclocarbonylation of these moieties to 1H-cyclopenta[a]inden-2-ones proceeds smoothly using suitable molybdenum carbonyl reagents, with Mo(CO)3(CH3CN) 3 being the most efficient. The yields of desired bicyclic ketones were up to 87-93%.
Methylation of naphthalene on MTW-type zeolites. Influence of template origin and substitution of Al by Ga
Wu, Wei,Wu, Weiguo,Kikhtyanin,Li, Lingfei,Toktarev,Ayupov,Khabibulin,Echevsky,Huang, Juan
, p. 279 - 288 (2010)
Two templates, methyltriethylammonium bromide (MTEA) and tetraethylammonium bromide (TEA) were used to synthesize aluminosilicate ZSM-12 zeolites. Additionally, zeolites isomorphously substituted (partially or totally) by gallium were prepared with MTEA.
Acid-Catalyzed Photoisomerization of 2-Alkylindenes to 2-Alkylideneindanes
Morrison, Harry,Giacherio, David
, p. 1058 - 1063 (1982)
Photolysis of 2-alkylindenes in aprotic media containing hydrochloric acid leads to the formation of 2-alkylideneindanes with concomitant quenching of the previously reported phototransposition reaction.Quantum efficiencies range from 0.02 to 0.1 and, as with the tranposition reaction, are highest for those indenes having short singlet lifetimes.Though there is evidence that the reaction is derived from the singlet excited state, acid has no effect on fluorescence and therefore intervenes by protonating an intermediate formed from S1.This intermediate (proposed as the bicyclopentene "I") is common to both the transposition and the olefin migration (cf.Scheme III).
Short Access to Belt Compounds with Spatially Close C=C Bonds and Their Transannular Reactions
Camps, Pelayo,G?mez, Tània,Otermin, Ane,Font-Bardia, Mercè,Estarellas, Carolina,Luque, Francisco Javier
, p. 14036 - 14046 (2015)
Two domino Diels-Alder adducts were obtained from 3,7-bis(cyclopenta-2,4-dien-1-ylidene)-cis-bicyclo[3.3.0]octane and dimethyl acetylenedicarboxylate or N-methylmaleimide under microwave irradiation. From the first adduct, a C20H24 diene with C2v symmetry was obtained by Zn/AcOH reduction, hydrolysis, oxidative decarboxylation, and selective hydrogenation. Photochemical [2+2] cycloaddition of this diene gave a thermally unstable cyclobutane derivative, which reverts to the diene. However, both the diene and the cyclobutane derivatives could be identified by X-ray diffraction analysis upon irradiation of the diene crystal. New six-membered rings are formed upon the transannular addition of bromine or iodine to the diene. The N-type selectivity of the addition was examined by theoretical calculations, which revealed the distinct susceptibility of the doubly bonded carbon atoms to the bromine attack. Short access: A polycyclic C20H24 hydrocarbon with two spatially close C=C bonds that experience photochemical conversion to a thermally unstable cyclobutane derivative and N-type transannular addition of bromine or iodine has been obtained from a domino Diels-Alder adduct of the shown difulvene. The mechanism of the N-type bromination is examined by DFT computations.
Negative correlations between cultivable and active-yet-uncultivable pyrene degraders explain the postponed bioaugmentation
Jiang, Bo,Chen, Yating,Xing, Yi,Lian, Luning,Shen, Yaoxin,Zhang, Baogang,Zhang, Han,Sun, Guangdong,Li, Junyi,Wang, Xinzi,Zhang, Dayi
, (2021/09/24)
Bioaugmentation is an effective approach to remediate soils contaminated by polycyclic aromatic hydrocarbons (PAHs), but suffers from unsatisfactory performance in engineering practices, which is hypothetically explained by the complicated interactions between indigenous microbes and introduced degraders. This study isolated a cultivable pyrene degrader (Sphingomonas sp. YT1005) and an active pyrene degrading consortium (Gp16, Streptomyces, Pseudonocardia, Panacagrimonas, Methylotenera and Nitrospira) by magnetic-nanoparticle mediated isolation (MMI) from soils. Pyrene biodegradation was postponed in bioaugmentation with Sphingomonas sp. YT1005, whilst increased by 30.17% by the active pyrene degrading consortium. Pyrene dioxygenase encoding genes (nidA, nidA3 and PAH-RHDα-GP) were enriched in MMI isolates and positively correlated with pyrene degradation efficiency. Pyrene degradation by Sphingomonas sp. YT1005 only followed the phthalate pathway, whereas both phthalate and salicylate pathways were observed in the active pyrene degrading consortium. The results indicated that the uncultivable pyrene degraders were suitable for bioaugmentation, rather than cultivable Sphingomonas sp. YT1005. The negative correlations between Sphingomonas sp. YT1005 and the active-yet-uncultivable pyrene degraders were the underlying mechanisms of bioaugmentation postpone in engineering practices.
Ceramic boron carbonitrides for unlocking organic halides with visible light
Yuan, Tao,Zheng, Meifang,Antonietti, Markus,Wang, Xinchen
, p. 6323 - 6332 (2021/05/19)
Photochemistry provides a sustainable pathway for organic transformations by inducing radical intermediates from substrates through electron transfer process. However, progress is limited by heterogeneous photocatalysts that are required to be efficient, stable, and inexpensive for long-term operation with easy recyclability and product separation. Here, we report that boron carbonitride (BCN) ceramics are such a system and can reduce organic halides, including (het)aryl and alkyl halides, with visible light irradiation. Cross-coupling of halides to afford new C-H, C-C, and C-S bonds can proceed at ambient reaction conditions. Hydrogen, (het)aryl, and sulfonyl groups were introduced into the arenes and heteroarenes at the designed positions by means of mesolytic C-X (carbon-halogen) bond cleavage in the absence of any metal-based catalysts or ligands. BCN can be used not only for half reactions, like reduction reactions with a sacrificial agent, but also redox reactions through oxidative and reductive interfacial electron transfer. The BCN photocatalyst shows tolerance to different substituents and conserved activity after five recycles. The apparent metal-free system opens new opportunities for a wide range of organic catalysts using light energy and sustainable materials, which are metal-free, inexpensive and stable. This journal is
Iodine-catalyzed alcohol disproportionation method
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Paragraph 0036-0037, (2021/06/13)
The invention relates to the technical field of catalysis, in particular to an iodine-catalyzed alcohol disproportionation method which comprises the following steps: sequentially adding alcohol, iodine and a solvent into a high-temperature and high-pressure reaction kettle, introducing a certain amount of nitrogen, conducting reacting for a certain time, collecting an organic phase after the reaction is ended, and conducting fractionating to obtain corresponding alkane and aldehyde/ketone. Alcohol disproportionation is efficient and atom-economical conversion without any additional oxidizing agent and reducing agent, and hydrocarbon and aldehyde/ketone molecules which are easy to separate can be formed at the same time. Meanwhile, the method has wide functional group tolerance, various substrate samples including aryl alcohol derivatives, heterocyclic alcohol derivatives, allyl alcohol derivatives and dihydric alcohol are tested, and the result shows that most of the substrate samples show good or extremely good yield.
Chemoselective Deoxygenation of 2° Benzylic Alcohols through a Sequence of Formylation and B(C6F5)3-Catalyzed Reduction
Oestreich, Martin,Richter, Sven C.
supporting information, p. 2103 - 2106 (2021/07/22)
A sequence of formylation and B(C6F5)3-catalyzed reduction of the resulting formate with Et3SiH enables the chemoselective deoxygenation of secondary benzylic alcohols. Primary benzylic and tertiary non-benzylic alcohols are not reduced by this protocol. The formyl group fulfills a double role as activator and self-sacrificing protecting group. The deoxygenation of these formates is fast and can be carried out in the presence of other potentially reducible groups. Neighboring-group participation was found in the deoxygenation of certain diol motifs.
Arylketones as Aryl Donors in Palladium-Catalyzed Suzuki-Miyaura Couplings
Wang, Zhen-Yu,Ma, Biao,Xu, Hui,Wang, Xing,Zhang, Xu,Dai, Hui-Xiong
supporting information, p. 8291 - 8295 (2021/11/13)
Herein, we report the arylation, alkylation, and alkenylation of aryl ketones via a palladium-catalyzed Suzuki-Miyaura cross-coupling reaction. The use of the pyridine-oxazoline ligand is the key to the cleavage of the unstrained C-C bond. The late-stage arylation of aryl ketones derived from drugs and natural products demonstrated the synthetic utility of this protocol.
