The methylation of benzyl-type alcohols with dimethyl carbonate in the presence of Y- and X-faujasites: selective synthesis of methyl ethers

Selva, Maurizio; Militello, Enrico; Fabris, Massimo

doi:10.1039/b707774b

Cited by 41 publications

(28 citation statements)

References 52 publications

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“…Some researchers report that more sodium or aluminium sites in zeolites are advantageous to adsorb benzyl alcohol. [16,22] Nevertheless, we have not observed a quantitative relation between the content of sodium or aluminium in zeolites (see Table 2) and the catalytic activities of Au/zeolite catalysts. In addition, the surrounding environments of the supports also affect the dielectric constant and the oscillation frequency of excited electrons in Au-NPs due to the varying abilities of the support surfaces to accommodate the electron density of Au-NPs.…”

Section: Effect Of Properties Of Au-nps and Zeolite Supports On Catalmentioning

confidence: 70%

Zeolite‐Supported Gold Nanoparticles for Selective Photooxidation of Aromatic Alcohols under Visible‐Light Irradiation

Zhang¹,

Ke²,

Zhu³

2012

Chemistry A European J

110

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With new photocatalysts of gold nanoparticles supported on zeolite supports (Au/zeolite), oxidation of benzyl alcohol and its derivatives into the corresponding aldehydes can proceed well with a high selectivity (99 %) under visible-light irradiation at ambient temperature. Au/zeolite photocatalysts were characterised by UV/Vis, X-ray photoelectron spectroscopy (XPS), TEM, XRD, energy-dispersive spectroscopy (EDS), Brauner-Emmet-Teller (BET) analyses, IR and Raman techniques. The surface plasmon resonance (SPR) effect of gold nanoparticles, the adsorption capability of zeolite supports and the molecular polarities of aromatic alcohols were demonstrated to have an essential correlation with the photocatalytic performances. In addition, the effects of light intensity, wavelength range and the role of molecular oxygen were investigated in detail. The kinetic study indicated that the visible-light irradiation required much less apparent activation energy for photooxidation compared with thermal reaction. Based on the characterisation data and the photocatalytic performances, we proposed a possible photooxidation mechanism.

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Section: Effect Of Properties Of Au-nps and Zeolite Supports On Catalmentioning

confidence: 70%

Zeolite‐Supported Gold Nanoparticles for Selective Photooxidation of Aromatic Alcohols under Visible‐Light Irradiation

Zhang¹,

Ke²,

Zhu³

2012

Chemistry A European J

110

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“…[20] Unlike aromatic or benzyl substrates, [14,21,22] solketal has ac ycloaliphatic structure, which could be more weakly coordinated to the FAUs urface and, thereby,a lter the reaction outcome. [20] Unlike aromatic or benzyl substrates, [14,21,22] solketal has ac ycloaliphatic structure, which could be more weakly coordinated to the FAUs urface and, thereby,a lter the reaction outcome.…”

Section: Cf Tests Over Different Catalystsmentioning

confidence: 99%

“…This behaviour neatly contrasted with our previously reported resultsf or the reactiono fb enzyl-type alcohols with DMC, through which the corresponding O-methyl ethers were achieved quantitatively and selectively in the presence of NaX and NaY catalysts. [20] Unlike aromatic or benzyl substrates, [14,21,22] solketal has ac ycloaliphatic structure, which could be more weakly coordinated to the FAUs urface and, thereby,a lter the reaction outcome. On the basis of the hard and soft acids and bases (HSAB)p rinciple, other authors have also proposed that hard nucleophiless uch as aliphatic alcohols prefert he hard electrophilics ite of DMC (i.e.,t he carboxyl carbon atom) rather than the softer methylg roup.…”

Section: Cf Tests Over Different Catalystsmentioning

confidence: 99%

Continuous‐Flow O‐Alkylation of Biobased Derivatives with Dialkyl Carbonates in the Presence of Magnesium–Aluminium Hydrotalcites as Catalyst Precursors

et al. 2017

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The base-catalysed reactions of OH-bearing biobased derivatives (BBDs) including glycerol formal, solketal, glycerol carbonate, furfuryl alcohol and tetrahydrofurfuryl alcohol with non-toxic dialkyl carbonates (dimethyl and diethyl carbonate) were explored under continuous-flow (CF) conditions in the presence of three Na-exchanged Y- and X-faujasites (FAUs) and four Mg-Al hydrotalcites (HTs). Compared to previous etherification protocols mediated by dialkyl carbonates, the reported procedure offers substantial improvements not only in terms of (chemo)selectivity but also for the recyclability of the catalysts, workup, ease of product purification and, importantly, process intensification. Characterisation studies proved that both HT30 and KW2000 hydrotalcites acted as catalyst precursors: during the thermal activation pre-treatments, the typical lamellar structure of the hydrotalcite was broken down gradually into a MgO-like phase (periclase) or rather a magnesia-alumina solid solution, which was the genuine catalytic phase.

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“…20 This observation prompted us to examine the role of the co-product water (Scheme 6) to promote hydrolytic processes of carbonate-like derivatives 4a and 6a, and of GlyC itself, in the presence of faujasites as catalysts.…”

Section: Investigation Of the Reaction Mechanismmentioning

confidence: 99%

The reaction of glycerol carbonate with primary aromatic amines in the presence of Y- and X-faujasites: the synthesis of N-(2,3-dihydroxy)propyl anilines and the reaction mechanism

Selva

Fabris

2009

Green Chem.

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At 140• C, in the presence of alkali metal exchanged faujasites, preferably NaY, as catalysts, glycerine carbonate (GlyC) is an efficient and green alkylating agent of primary aromatic amines (p-XC 6 H 4 NH 2 , X = H, OMe, OH, Cl): the reaction takes place with a high conversion (~90%) and a good selectivity (80-90%) for the formation of N- (2,3-dihydroxy)propyl anilines (p-XC 6 H 4 NHCH 2 CH(OH)CH 2 OH). The alkylation process does not proceed through an exclusive nucleophilic substitution of anilines at the C5 position of GlyC. Evidence proves that a dehydrative condensation of anilines with GlyC produces intermediate species, and both transesterification and hydrolysis reactions are involved to obtain the final N-alkyl derivatives. A mechanism is proposed accordingly. Experiments show that faujasites are recyclable catalysts on condition that they are exposed to a mild thermal activation (70 • C, 18 mbar) prior to their re-use.Otherwise, if zeolites are calcined (400 • C, air), both the catalyst activity and the reaction selectivity drop. Isolated yields (60-65%) of N- (2,3-dihydroxy)propyl anilines are somewhat limited by the difficult separation of the unreacted GlyC and of the by-product glycerine. Nonetheless, the overall efficiency of the method is comparable to that of alternative routes based on highly toxic reagents (glycidol and aryl halides).

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The methylation of benzyl-type alcohols with dimethyl carbonate in the presence of Y- and X-faujasites: selective synthesis of methyl ethers

Cited by 41 publications

References 52 publications

Zeolite‐Supported Gold Nanoparticles for Selective Photooxidation of Aromatic Alcohols under Visible‐Light Irradiation

Zeolite‐Supported Gold Nanoparticles for Selective Photooxidation of Aromatic Alcohols under Visible‐Light Irradiation

Continuous‐Flow O‐Alkylation of Biobased Derivatives with Dialkyl Carbonates in the Presence of Magnesium–Aluminium Hydrotalcites as Catalyst Precursors

The reaction of glycerol carbonate with primary aromatic amines in the presence of Y- and X-faujasites: the synthesis of N-(2,3-dihydroxy)propyl anilines and the reaction mechanism

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