Reaction Of Benzyl Alcohol Research Articles

DFT study on the reaction mechanisms behind the catalytic oxidation of benzyl alcohol into benzaldehyde by O2 over anatase TiO2 surfaces with hydroxyl groups: Role of visible-light irradiation

Theoretical study on the catalytic oxidation of benzyl alcohol by molecular oxygen (O2) on the TiO2 surface was performed by DFT calculations. The anatase TiO2 crystal faces in the absence and presence of surface hydroxyl groups were modeled with a slab of Ti16O32 and Ti16O32(OH)H, respectively. The interaction of benzyl alcohol with Ti16O32 and Ti16O32(OH)H was calculated. It was clearly demonstrated that the surface hydroxyl groups on the TiO2 surface play a significant role in the formation of the alkoxide ([Ti]OCH2−ph) species. The orbitals of the alkoxide species was found to be hybridized with the O2p orbital in the valence band (VB) of the TiO2. The origin of the visible-light response in the photocatalytic system can be attributed to the electronic transition from the donor levels created by the alkoxide species to the conduction band (CB). Furthermore, reaction coordinates in the overall catalytic reaction of benzyl alcohol into benzaldehyde on the TiO2 surface were demonstrated, and the role of the visible-light irradiation was also discussed.

A novel method for preparation of MNP@CS-tethered coenzyme for coupled oxidoreductase system

The immobilized cofactor NAD(H) is easily recovered from the reaction bulk, which is essential for repeated use of NAD(H) in the bioprocess catalyzed by NAD(H)-dependent oxidoreductase. Here, a magnetic nanoparticle platform was designed to immobilize both of the NADH and the NAD+. The design was based on chitosan-coated magnetic nanoparticles (MNP@CS) which was activated by the EDC/NHS with the aid of azelaic acid as spacer. Interestingly, the succinimide group at the end of spacer arm catalyzed direct coupling of a carboxyl-terminal to the 6-amino group of the adenine residue of NAD(H). Our results indicated that 150μmol NADH and 50μmol NAD+ was effectively attached to 1g MNP@CS at 25°C in 120min and the prepared MNP@CS–NAD(H) showed good activity according to the coupling reaction of benzyl alcohol and acetaldehyde catalyzed by alcohol dehydrogenase.

Mild and metal-free oxy- and amino-fluorination for the synthesis of fluorinated heterocycles.

A mild intramolecular fluoro-cyclisation reaction of benzylic alcohols and amines has been developed. This strategy uses commercially available Selectfluor to trigger electrophilic cyclisations to afford fluorinated heterocycles containing 1,3-disubstitution. The dual role of the reagent as a fluorine source and a base is shown to be crucial for reactivity.

Tandem Catalysis by Palladium Nanoclusters Encapsulated in Metal–Organic Frameworks

A bifunctional Zr-MOF catalyst containing palladium nanoclusters (NCs) has been developed. The formation of Pd NCs was confirmed by transmission electron microscopy (TEM) and extended X-ray absorption fine structure (EXAFS). Combining the oxidation activity of Pd NCs and the acetalization activity of the Lewis acid sites in UiO-66-NH2, this catalyst (Pd@UiO-66-NH2) exhibits excellent catalytic activity and selectivity in a one-pot tandem oxidation-acetalization reaction. This catalyst shows 99.9% selectivity to benzaldehyde ethylene acetal in the tandem reaction of benzyl alcohol and ethylene glycol at 99.9% conversion of benzyl alcohol. We also examined various substituted benzyl alcohols and found that alcohols with electron-donating groups showed better conversion and selectivity compared to those with electron-withdrawing groups. We further proved that there was no leaching of active catalytic species during the reaction and the catalyst can be recycled at least five times without significant deactivation.

Transition-metal-free oxidative amidation of benzyl alcohols with amines catalyzed by NaI: a new method for the synthesis of benzamides

A simple, inexpensive, and efficient method for the synthesis of benzamides via the reaction of benzyl alcohols and amine hydrochloride salts in the presence of NaI as a green catalyst is described. Various derivatives of benzamide were synthesized in moderate to good yields using this method.

Synthesis, characterization and crystal structure of a manganese(III) Schiff base complex and investigation of its catalytic activity in the oxidation of benzylic alcohols

A new Mn(III) Schiff base complex was prepared by the reaction of 6,6′-diethoxy-2,2′-[2,2-dimethylpropane-1,3-diylbis(nitrilomethylidyne)]diphenol with Mn(OAc)2·4H2O. The complex was characterized by physicochemical and spectroscopic methods. Also, its molecular structure was determined by single-crystal X-ray diffraction. The complex was used as a catalyst for the efficient oxidation of benzylic alcohols with tetrabutylammonium periodate. Various reaction parameters were optimized for the reaction of benzyl alcohol.

QM/MM Study for the Reaction Mechanisms of Benzyl Alcohol with Dimethyl Carbonate over a Faujasite Zeolite Catalyst

Benzyl methyl ether (BME) compounds are largely synthesized by the industry for use as a starting material for the synthesis of other organic compounds. In order to achieve the target of green chemistry, BME can be synthesized from benzyl alcohol and dimethyl carbonate (DMC) using a zeolite catalyst. DMC is a non toxic compound and a good methylating and carboxymethylating agent. The methylation and carboxymethylation reactions of benzyl alcohol over a 36T extended framework was investigated by ONIOM(HF/3-21g:UFF). Two pathways for the methylation reaction were found, where the first involving two transition states (TS) and the second only a single TS. Methylation via the two-TS pathway has a lower activation energy compared to the single-transition state pathway. Also, the methylation reaction is kinetically more favorable than the carboxymethylation reaction and this finding agrees well with the previous experimental results. The rate constant for the studied reactions were calculated by using the transition state theory and the rate determining step was determined.

Solvothermal synthesis, structure and electronic properties of a benzyl viologen mixed-haloplumbate

Solvothermal reactions of benzyl alcohol with 4,4'-bipyridine, PbCl₂, and I₂ in water and acetonitrile afforded a unique benzyl viologen mixed-haloplumbate containing chloride and iodide [(BV)₂(Pb₅I₈Cl₆)]<italic>_n</italic> (<bold>1</bold>) (BV²⁺ = benzyl viologen or <italic>N</italic>,<italic>N</italic>'-dibenzyl-4,4'-dipyridinium). The anionic part of <bold>1</bold> may be visualized as having a 1D [Pb₅I₈Cl₆]<italic>_n</italic>^{4<italic>n</italic>-} chain structure derived from sharing edges of PbI₃Cl₃, PbI₅Cl or PbI₆ octahedrons. The BV²⁺dications are <italic>in situ</italic> generated from the cleavage of the C-O bond of benzyl alcohol followed by benzyling 4,4'-bipyridine. The electrical conductivity of the single crystal of <bold>1</bold> was increased from 1.54×10^-⁶ to 2.11×10^-⁵ S m^-1 in the range of 293-443 K, which showed that <bold>1</bold> possesses the evident semiconducting behavior.

Undecatungstophosphate anchored to MCM-41: An ecofriendly and efficient bifunctional solid catalyst for non-solvent liquid-phase oxidation as well as esterification of benzyl alcohol

Undecatungstophosphate anchored to MCM-41 was synthesized and characterized by various physicochemical techniques. The bifunctional catalytic activity was evaluated for esterification as well oxidation reactions of benzyl alcohol. The influence of different parameters such as molar ratio, amount of catalyst, reaction time and reaction temperature on oxidation as well as esterification of benzyl alcohol was investigated for maximum conversion. Detailed kinetic studies reveal that the reactions follow first order kinetics and the low values of activation energy for esterification and oxidation indicates that the reaction rate is truly governed by the chemical step. The present bifunctional catalyst can be recycled without any significant difference in % conversion for both reactions. Further, oxidation and esterification of various alcohols were also carried out under optimized conditions to see the effect of chain length and type of alcohols.

Gold nanoparticle supported on ionic liquid-modified graphene oxide as an efficient and recyclable catalyst for one-pot oxidative A3-coupling reaction of benzyl alcohols

A novel gold nanoparticle supported on graphene oxide with ionic liquid framework was used as a highly active and recyclable catalyst for novel domino oxidative A3-coupling reaction.

Synthesis, characterization and applications of highly active and robust sulfated Fe–TiO2 catalyst (ICT-3) with superior redox and acidic properties

A novel multifunctional sulfated Fe–TiO2 catalyst with different Fe loading, leading to the introduction of both redox and superacidic properties (designated as ICaT-3), was developed. Chorosulfonic acid was used to create super acidity in the catalyst matrix. The catalyst was characterized by FT-IR, XRD, TG-DTA, surface area measurements, NH3-TPD, XPS, SEM and EDX analysis with reference to its superior redox and acidic properties. The catalyst was found to be very active and selective as compared to unsulfated catalyst for industrially important oxidation reaction of benzyl alcohol to benzaldehyde and its efficacy was tested in a variety of substrates such as 4-methoxy benzyl alcohol, 4-chlorobenzyl alcohol, styrene, p-bromostyrene, and methyl phenyl sulfide. This induced acidity increases the oxidation activity by twofold as compared to conventional TiO2 catalyst. Its superior acidic properties were also evaluated in the alkylation of toluene with benzyl alcohol. The catalyst was reused repeatedly to find it as stable and reusable.

Graphene Oxide as Support for the Immobilization of Phosphotungstic Acid: Application in the Selective Oxidation of Benzyl Alcohol

Graphene oxide functionalized with gama-aminopropyltriethoxysilane, is used as support for the immobilization of homogeneous heteropoly phosphotungstic acid. It is synthesized and characterized by SEM, XPS, XRD, 31P NMR and Raman. The effects of catalyst parameters and reaction conditions on the oxidation reaction of benzyl alcohol are systematically investigated. Under optimal conditions, the catalyst exhibit remarkably enhanced catalytic activity (conversion 76 % and selectivity 99 %). And the catalyst could be separated conveniently. Moreover, the loss of PW12O40 3− anion from the support under the reaction conditions is responsible for the deactivation of the catalyst. SEM images of a GO, b GO–N, c GO–N–PW (inset XPS spectrum of carbon), d GO–N–PW reused (inset XPS spectrum of carbon). The mechanism of deactivation was testified using the SEM images and the XPS spectrums in c (inset) and d (inset) .

PdNPs@P2VP-Fe3O4 Organic–Inorganic Hybrid Microgels as a Nanoreactor for Selective Aerobic Oxidation of Alcohols

The preparation of organic–inorganic hybrid microgels with functional Fe3O4 nanoparticles as the crosslinker and 2-vinyl pyridine (2VP) as the pH-sensitive monomer is reported. Magnetic Fe3O4 nanoparticles were first synthesized via a redox reaction and then modified with 3-(trimethoxysilyl)propylmethacrylate (TMSPMA) via the silanization. The bonding of multiple TMSPMA monomers on the surface of Fe3O4 nanoparticles renders them as crosslinker. Radical polymerization of 2VP was then carried out with the presence of TMSPMA-modified Fe3O4 nanoparticles, leading to the formation of P2VP-Fe3O4 hybrid microgels crosslinked with Fe3O4 nanoparticles. The synthesized hybrid microgels are able to trap metal ions such as Pd2+ via complex formation of P2VP with metal ions. The reduction of trapped palladium ions by sodium borohydride led to immobilized-palladium nanoparticles. The synthesized PdNPs@P2VP-Fe3O4 is employed as a new nanocatalyst toward oxidation reaction of alcohols. In addition, the catalytic activity of metal nanocomposite has been found that can be modulated by the volume transition of microgel structures by pH change for the oxidation reaction of benzyl alcohol. Transmission electron microscopy, thermogravimetric analysis, vibrating sample magnetometer, scanning electron microscopy, X-ray powder diffraction, Atomic absorption and Fourier transform Infrared were then used to characterize the resultant catalyst.

Immobilized 2,2,6,6-tetramethyl-piperidinyl-1-oxy catalyst on polymer microspheres and its catalytic oxidation of benzyl alcohol with molecular oxygen

Crosslinked polymer (glycidyl methacrylate) microspheres (CPGMA) were prepared with glycidyl methacrylate as monomer and ethylene dimethacrylate as crosslinker by suspension polymerization. The ring opening reaction between the epoxy groups on the CPGMA microspheres and 4-hydroxy-2,2,6,6-tetramethyl-piperidinyl-1-oxy (4-OH-TEMPO) was carried out to immobilize TEMPO on the polymer microspheres. TEMPO-immobilized microspheres (TEMPO/CPGMA) were obtained and were characterized by several methods. The effects of the main factors in the immobilization were examined so that the reaction conditions were optimized. On this basis, a co-catalyst system was constituted with TEMPO/CPGMA and CuCl and was used in the oxidation reaction of benzyl alcohol by molecular oxygen. The catalytic activity of the co-catalyst system and the effects of the main factors were examined. The experimental results showed that the ring opening reaction of the epoxy group allowed the immobilization of TEMPO to be smoothly realized on the CPGMA polymer microspheres, on which there were many epoxy groups. The ring opening reaction of the epoxy group is a nucleophilic substitution reaction with the SN2 reaction mechanism, and N,N′-dimethyl formamide with a strong polarity is an appropriate solvent and a suitable temperature is 85 °C. The co-catalyst system consisting of the heterogeneous catalyst TEMPO/CPGMA and CuCl efficiently catalyzed the oxidation reaction of benzyl alcohol by molecular oxygen. Under mild conditions, benzyl alcohol was transformed to benzaldehyde with 100% selectivity and a yield of 90%. The suitable molar ratio of the main catalyst TEMPO/CPGMA to the co-catalyst CuCl is 1:1.2 and the suitable amount of TEMPO/CPGMA is 0.90 g. The TEMPO/CPGMA catalyst has excellent recyclability.

ChemInform Abstract: One‐Pot Synthesis of Indene Derivatives by CF3SO3H‐Promoted Reactions of Benzylic Alcohols and 1,3‐Dicarbonyl Compounds.

AbstractThe coupling/cyclization sequence produces indene structures of type (III) as main or exclusive regioisomers.

One-pot synthesis of imines from benzyl alcohol and amines on Au/ZrO2 catalyst

Imines were synthesized from benzyl alcohol and amines by using catalysts of gold nanoparticles supported on ZrO2 (Au/ZrO2). The effects of reaction time, temperature, gold loadings and base were investigated. High yields were achieved under moderate conditions (60 °C) in the presence of KOCH3. For instance, the yield of N-benzylidenebenzylamine produced from benzyl alcohol and benzylamine on 3 wt% Au/ZrO2 is 87 %. The synthesis of imine involves two reaction steps: selective oxidation of benzyl alcohol to benzaldehyde and the coupling reaction of amines with benzaldehyde. In the first step, the base promotes the selective oxidation. The reactions of benzyl alcohol with three different amines, aniline, n-butylamine and benzylamine, were conducted to produce corresponding imines. The results show that the amine with stronger nucleophilicity has better ability to react with benzaldehyde in the second step, resulting in higher yield of the corresponding imine. We proposed a tentative mechanism for the synthesis process.

One-pot synthesis of indene derivatives by CF3SO3H-promoted reactions of benzylic alcohols and 1,3-dicarbonyl compounds

An efficient and convenient one-pot synthesis of indene derivatives was achieved in moderate to high yields by the CF3SO3H promoted coupling/cyclization reaction of benzylic alcohols and 1,3-dicarbonyls for the first time. For the reactions of methoxy- or methyl-substituted diarylmethanols with 1,3-dicarbonyls, 2equiv of CF3SO3H was needed to reach the best results; but for the reactions of methoxy-substituted arylethanols with 1,3-dicarbonyls, 0.6equiv of CF3SO3H at lower temperatures was capable of promoting the reaction finished.

ChemInform Abstract: Zn(OTf)2‐Catalyzed Direct Cyanation of Benzylic Alcohols — A Novel Synthesis of α‐Aryl Nitriles.

AbstractOptimized conditions are developed for the reaction of benzylic alcohols with trimethylsilyl cyanide.

New facile way to isomorphously substituted Cr-β zeolite and its catalytic performance

A new facile way was reported to incorporate high amount of chromium ions into the framework of BEA by a directly static hydrothermal route through the co-hydrolysis of TEOS with metal ions in acidic media. Various synthesis parameters including the co-hydrolysis route, Cr2O3/SiO2, alkalinity, and crystallization time were investigated to obtain the suitable conditions. The synthesized samples were characterized by IR, ICP, UV–vis and SEM. The results showed that the metal ions were incorporated into the crystal lattice of BEA. The catalytic performance was assessed in the oxidation of benzyl alcohol reaction, and the framework Cr demonstrated superior activity than impregnated Cr2O3 particles. Meanwhile, the recycling test of Cr-substituted β zeolite was studied for the first time, and the good catalytic stability gave a further proof of incorporation of Cr into zeolite framework.

Synthesis, characterization and catalytic properties of novel palladium(II) complexes containing aromatic sulfonamides: effective catalysts for the oxidation of benzyl alcohol

In this article, N‐(2‐aminophenyl)arylsulfonamides (1–5) were successfully synthesized by the reaction of o‐phenylenediamine and various benzenesulfonyl chlorides. The Schiff base derivatives (1a–f; 4e) of those compounds were obtained using different aldehydes. Then, a series of neutral‐four coordinate Pd(II) complexes (6–10) were prepared from the reaction of Pd(OAc)2 and 1–5. On the other hand, when we tried to synthesize Pd(II) complexes containing Schiff base/sulfonamide ligands, two different situations were observed. Generally, when an electron‐donating group was attached to the imine fragment (1a–d) except for 1f, the Schiff base hydrolyzed and 6 was isolated. When an electron‐withdrawing group was attached to the imine fragment (1e, 4e), neutral four‐coordinate Pd(II) complexes (11–13) bearing Schiff base/sulfonamide ligands were isolated. The synthesized compounds were characterized by FT‐IR, elemental analysis and NMR spectroscopy. The complexes were used as a catalyst in the oxidation reaction of benzyl alcohol to benzaldehyde in the presence of H5IO6 in acetonitrile. All complexes showed satisfactory catalytic activity. The highest catalytic activity was obtained with 9. Copyright © 2012 John Wiley &amp; Sons, Ltd.