28122-25-0Relevant academic research and scientific papers
Green, Mild, and Efficient Friedel–Crafts Benzylation of Scarcely Reactive Arenes and Heteroarenes under On-Water Conditions
La Manna, Pellegrino,Soriente, Annunziata,De Rosa, Margherita,Buonerba, Antonio,Talotta, Carmen,Gaeta, Carmine,Neri, Placido
, p. 1673 - 1683 (2019/03/26)
Metal-free Friedel–Crafts benzylation (FCB) of scarcely reactive arenes and heteroarenes was performed under on-water conditions by an environmentally sustainable procedure. The catalytic strategy exploits the hydrophobicity of the resorcinarene macrocycle 1 a. The proposed mechanism is based on the activation of benzyl chloride by H-bonding interactions with catalyst 1 a. In fact, under on-water conditions the hydrophobic amplification of the strength of the H-bonding interactions between the OH groups of the resorcinarene catalyst and the chlorine atom of benzyl chloride leads to polarization of the C?Cl bond, which consequently promotes electrophilic attack of the π nucleophile. Thus, many arenes and heteroarenes were efficiently benzylated under mild on-water conditions by using resorcinarene 1 a as catalyst. The FCB of benzene is industrially relevant for the synthesis of diphenylmethane, and hence the on-water procedure was extended to the gram-scale synthesis of diphenylmethane, starting from benzene and benzyl chloride in the presence of resorcinarene catalyst 1 a.
Mild Friedel–Crafts Reactions inside a Hexameric Resorcinarene Capsule: C?Cl Bond Activation through Hydrogen Bonding to Bridging Water Molecules
La Manna, Pellegrino,Talotta, Carmen,Floresta, Giuseppe,De Rosa, Margherita,Soriente, Annunziata,Rescifina, Antonio,Gaeta, Carmine,Neri, Placido
, p. 5423 - 5428 (2018/04/09)
A novel catalytic feature of a hexameric resorcinarene capsule is highlighted. The self-assembled cage was exploited to promote the Friedel–Crafts benzylation of several arenes and heteroarenes with benzyl chloride under mild conditions. Calculations showed that there are catalytically relevant hydrogen-bonding interactions between the bridging water molecules of the capsule and benzyl chloride, which is fundamental for the activation of the C?Cl bond. The capsule controls the reaction outcome. Inside the inner cavity of the capsule, N-methylpyrrole is preferentially benzylated in the unusual β-position while mesitylene reacts faster than 1,3-dimethoxybenzene despite the greater π-nucleophilicity of the latter compound.
MoO3 supported on ordered mesoporous zirconium oxophosphate: An efficient and reusability solid acid catalyst for alkylation and esterification
Miao, Zhichao,Li, Zhenbin,Zhao, Jinping,Si, Weijiang,Zhou, Jin,Zhuo, Shuping
, p. 10 - 21 (2017/12/06)
A series of molybdenum oxide supported on ordered mesoporous zirconium oxophosphate (MoO3/M-ZrPO) materials with different MoO3 loadings (0–20 wt%) and calcination temperatures (500–900 °C) have been designed, synthesized and employed as solid acid catalysts in alkylation and esterification. The XRD, TG-DSC, H2-TPR, N2-physisorption and TEM characterizations were taken to investigate the structural properties and states of introduced MoO3 species. The influence of MoO3 loadings and calcination temperatures in catalytic performance was detailedly investigated and optimal catalytic activity was reached at 10 wt% MoO3 loadings and treated at 700 °C. Moreover, MoO3/M-ZrPO catalysts exhibited outstanding catalytic performance in Friedel-Crafts alkylation of different aromatic compounds and esterification of levulinic acid with 1-butanol. Furthermore, it was noteworthy that the catalyst had superior reusability and no noticeable declines were observed in catalytic performance even after seven runs.
Benzylation of arenes with benzyl ethers promoted by the in situ prepared superacid BF3-H2O
Li, Yu,Xiong, Yan,Li, Xueming,Ling, Xuege,Huang, Ruofeng,Zhang, Xiaohui,Yang, Jianchun
, p. 2976 - 2981 (2014/06/10)
An efficient and environmentally friendly benzylation of arenes with benzyl ethers as benzyl donors using BF3-Et2O to generate in situ the superacid BF3-H2O as an efficient promotor has been described. A wide variety of functional groups have been investigated and found to be compatible to give the desired diarylmethanes in yields of up to 99%. The crucial role of the moisture content in this transformation has been demonstrated by detailed investigations. This journal is the Partner Organisations 2014.
Friedel-Crafts alkylations on nanoscopic inorganic fluorides
Candu,Wuttke,Kemnitz,Coman,Parvulescu
experimental part, p. 169 - 174 (2011/10/05)
The catalytic potential of nanoscopic MFx (M = Mg, Al; x = 2, 3) has been investigated using batch Friedel-Crafts alkylation of aromatic compounds, including benzene, ethylbenzene, trimethylhydroquinone (TMHQ), and menadiol (MDL), with isophytol and benzyl alcohol. The conversion of isophytol was 100% in the reactions with trimethylhydroquinone (TMHQ), menadiol (MDL) and benzene while the highest selectivity in alkylated compounds was achieved with TMHQ (>99%). The different reaction rates of the alkylation reactions are due to the different nucleophylicities of the substrates, and therefore, due to their ability to delocalize the positive charge in the Wheland intermediate by inductive and resonance effects. The conversions of benzyl alcohol varied between 10 and 84% as a function of the catalyst nature and reaction conditions while the highest selectivity to monobenzyl derived compounds (25%) was achieved with ethylbenzene. The formation of high amounts of dibenzyl ether was also observed, indicating the presence of high amounts of Br?nsted acid sites in this type of catalysts.
Mesoporous zirconium phosphate catalyzed reactions: Synthesis of industrially important chemicals in solvent-free conditions
Sinhamahapatra, Apurba,Sutradhar, Narottam,Roy, Biplab,Tarafdar, Abhijit,Bajaj, Hari C.,Panda, Asit Baran
scheme or table, p. 22 - 30 (2011/02/23)
Mesoporous zirconium phosphate (m-ZrP) having high specific surface area and narrow pore size distributions is synthesized in basic medium using zirconium carbonate as source of zirconium. The concentration of phosphate in precursor solutions, as well as the calcination temperature, is found to influence the textural properties and acidity of synthesized m-ZrP significantly. Microscopic analysis indicates the presence of worm like pores with spherical morphology. The porous structure has remarkable thermal stability (up to 800 °C). DRIFT and NH3-TPD analysis suggest the presence of reasonable amount of Lewis and Bro?nsted acid sites. High catalytic activity of synthesized m-ZrP is observed towards Friedel-Craft (F.C.) benzylation reaction. The effect of acid strength of catalyst, reaction time, temperature and amount of catalyst towards Friedel-Craft benzylation reaction are also studied. The m-ZrP is highly active towards other acid catalyzed reactions in solvent-free conditions. The catalytic activity of m-ZrP is much higher than that of conventional layered ZrP. The catalysts were separated easily from reaction mixture, regenerated after a simple activation step and reused at least six times without significant loss in catalytic activity.
High catalytic efficiency of nanostructured molybdenum trioxide in the benzylation of arenes and an investigation of the reaction mechanism
Wang, Feng,Ueda, Wataru
experimental part, p. 742 - 753 (2009/10/01)
The synthesis and characterization of nanostructured MoO3 with a thickness of about 30 nm and a width of about 450 nm are reported. The composition formula of the MP (precipitation method) precursor was estimated to be [(NH4)2O]0.169·MoO 3· (H2O)0.239. The calcination of the precursor in air afforded nanostructured pellets of the α-MoO3 phase. The nano-structured MoO3 catalyst exhibited high efficiency in catalyzing the benzylation of various arenes with substituted benzyl alcohols, which were strikingly different to common bulk MoO3. Most reactions offered >99% conversion and >99% selectivity to monoalkylated compounds. MoO3 is a typical acid catalyst. However, the benzylation reaction over nanostructured MoO3 does not belong to the acid-catalyzed type or defect site-catalyzed type, since the catalyst has no acidity and defect site on surface. Characterization with thermal, spectroscopic, and electronic techniques reveal that the catalyst contains fully oxygen-coordinated MoO 6 octahedrons on the surface but partially reduced species (Mo 5+) within the bulk phase. The terminal oxygen atoms of Mo=O bonds on the (010) basal plane resemble oxygen anion radicals and act as active sites for the adsorption and activation of benzyl alcohols by electrophilic attack. Such sites are indispensable for catalytic reactions since the blocking of these sites by electron acceptors, such as tetracyanoethylene (TCNE), can greatly decrease catalytic activity. This work represents a successful example of combining a heterogeneous catalysis study with nanomaterial synthesis.
Nanostructured molybdenum oxides and their catalytic performance in the alkylation of arenes
Wang, Feng,Ueda, Wataru
supporting information; scheme or table, p. 3196 - 3198 (2009/02/04)
We report for the first time that nanostructured MoO3 is an excellent catalyst for the alkylation of a wide range of arenes with substituted benzyl alcohols as alkylating agents. The Royal Society of Chemistry.
Efficient and selective alkylation of arenes and heteroarenes with benzyl and allyl ethers using a Ir/Sn bimetallic catalyst
Podder, Susmita,Roy, Sujit
, p. 9146 - 9152 (2008/02/09)
A high-valent heterobimetallic catalyst namely [Ir2(COD)2(SnCl3)2(Cl)2(μ-Cl)2] (5 mol %), or dual catalyst system of [Ir(COD)Cl]2 (1 mol %) and SnCl4 (4 mol %), promotes the benzylation or allylation of arenes and heteroarenes using ethers as the alkylating agents. An electrophilic mechanism is proposed from a Hammett correlation.
Rare earth(III) perfluorooctanesulfonates catalyzed Friedel-Crafts alkylation in fluorous biphase system
Yi, Wen-Bin,Cai, Chun
, p. 831 - 833 (2007/10/03)
The catalyst of rare earth(III) perfluorooctanesulfonates (RE(OSO 2C8F17)3, RE = Sc, Y, La-Lu) were prepared from either rare earth chlorides(III) or oxides and perfluorooctanesulfonic acid. The perflates thus obtained act as novel catalysts for Friedel-Crafts alkylation in fluorous biphasic system. Perfluorohexane (C6F14), perfluoromethylcyclohexane (C7F 14), perfluorotoluene (C7F8), perfluorooctane (C8F18), perfluorooctyl bromide (C8F 17Br) and perfluorodecalin (C10F18, cis- and trans-mixture) can be used as fluorous solvents for this reaction. By simple separation of the fluorous phase containing only catalyst, alkylation can be repeated many times.
