Showing papers on "Benzaldehyde published in 2014"
TL;DR: In this paper, a coupled system of selective oxidation of aromatic alcohols to aromatic aldehydes and reduction of nitrobenzene into aniline was realized using CdS/g-C 3 N 4 composite as a photocatalyst under visible light illumination.
Abstract: A coupled system of selective oxidation of aromatic alcohols to aromatic aldehydes and reduction of nitrobenzene into aniline was realized using CdS/g-C 3 N 4 composite as a photocatalyst under visible light illumination. The CdS/g-C 3 N 4 composite photocatalyst was prepared by hydrothermal method. The photocatalyst was characterized by x-ray powder diffraction (XRD), UV–vis diffuse reflection spectroscopy (DRS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer–Emmett–Teller (BET) specific surface area. Compared with single g-C 3 N 4 and CdS, the CdS/g-C 3 N 4 photocatalyst exhibits enhanced photocatalytic activity and excellent photostability under visible light illumination. It demonstrates that the selective oxidation of aromatic alcohol into aromatic aldehyde is achieved by direct holes oxidation, and the reduction of nitrobenzene into aniline is reached by direct electrons reduction. The optimum percentage of CdS is 10 wt.%. Under illumination for 4 h, the conversion of benzyl alcohol and the yield of benzaldehyde are about 48.0% and 44.6%, and the conversion of nitrobenzene and the yield of aniline are about 49.2% and 26.0%, respectively. The synergic effect of g-C 3 N 4 and CdS, which can effectively separate and transfer photoexcited carriers, was proposed to be responsible for the enhancement of the photocatalytic activity. This study has a guiding significance for the design of a coupled system which realizes selective oxidation and reduction of organics.
237 citations
TL;DR: In this article, an Escherichia coli K-12 MG1655 strain with reduced aromatic aldehyde reduction (RARE) was constructed and applied to the synthesis of vanillin from vanillate and succeeded in preventing formation of vanillyl alcohol.
Abstract: Aromatic aldehydes are useful in numerous applications, especially as flavors, fragrances, and pharmaceutical precursors. However, microbial synthesis of aldehydes is hindered by rapid, endogenous, and redundant conversion of aldehydes to their corresponding alcohols. We report the construction of an Escherichia coli K-12 MG1655 strain with reduced aromatic aldehyde reduction (RARE) that serves as a platform for aromatic aldehyde biosynthesis. Six genes with reported activity on the model substrate benzaldehyde were rationally targeted for deletion: three genes that encode aldo-keto reductases and three genes that encode alcohol dehydrogenases. Upon expression of a recombinant carboxylic acid reductase in the RARE strain and addition of benzoate during growth, benzaldehyde remained in the culture after 24 h, with less than 12% conversion of benzaldehyde to benzyl alcohol. Although individual overexpression results demonstrated that all six genes could contribute to benzaldehyde reduction in vivo, additional experiments featuring subset deletion strains revealed that two of the gene deletions were dispensable under the conditions tested. The engineered strain was next investigated for the production of vanillin from vanillate and succeeded in preventing formation of the byproduct vanillyl alcohol. A pathway for the biosynthesis of vanillin directly from glucose was introduced and resulted in a 55-fold improvement in vanillin titer when using the RARE strain versus the wild-type strain. Finally, synthesis of the chiral pharmaceutical intermediate L-phenylacetylcarbinol (L-PAC) was demonstrated from benzaldehyde and glucose upon expression of a recombinant mutant pyruvate decarboxylase in the RARE strain. Beyond allowing accumulation of aromatic aldehydes as end products in E. coli, the RARE strain expands the classes of chemicals that can be produced microbially via aldehyde intermediates.
219 citations
TL;DR: In this paper, the mechanism of toluene oxidation at room temperature over Mn/HZSM-5, Ag/HzSM-6, and Mn-Ag/HazSM-7 catalysts was investigated by in situ DRIFTS.
183 citations
TL;DR: In this article, a bifunctional Zr-MOF catalyst containing palladium nanoclusters (NCs) has been developed, which exhibits excellent catalytic activity and selectivity in a one-pot tandem oxidation-acetalization reaction.
Abstract: 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 deactiva...
177 citations
TL;DR: Electron paramagnetic resonance spin trapping experiments demonstrate that benzyl alcohol intercepts, by hydrogen atom transfer, the benzoylperoxy radicals that play a key role in benzaldehyde autoxidation.
Abstract: Benzaldehyde readily undergoes autoxidation to form benzoic acid on exposure to air at room temperature. Yet it can be formed in high yield from, for example, benzyl alcohol by oxidation using a variety of procedures and catalysts. Here we report the evidence to resolve this apparent paradox. It is confirmed that benzyl alcohol (and a number of other alcohols), even at low concentrations in benzaldehyde, inhibits the autoxidation. Furthermore we report on the structural features required for inhibition. Electron paramagnetic resonance spin trapping experiments demonstrate that benzyl alcohol intercepts, by hydrogen atom transfer, the benzoylperoxy radicals that play a key role in benzaldehyde autoxidation. A similar inhibition effect has also been observed for the aliphatic octanal/1-octanol system.
170 citations
TL;DR: In this paper, a family of isoreticular metal-organic frameworks (MOFs) based on the UiO-66 structure were synthesized from the two linker ligands containing electron-donating NH 2 -groups (2-amino-benzenedicarboxylic acid (H 2 N-H 2 BDC)) and electron-withdrawing NO 2 -group (2nitro-bensenedic-arboxylated acid (O 2 n-H2 BDC)).
Abstract: A family of isoreticular metal-organic frameworks (MOFs), based on the UiO-66 structure, were synthesized from the two linker ligands containing electron-donating NH 2 -groups (2-amino-benzenedicarboxylic acid (H 2 N-H 2 BDC)) and electron-withdrawing NO 2 -groups (2-nitro-benzenedicarboxylic acid (O 2 N-H 2 BDC)). The catalytic performance of these materials was investigated with a combination of physicochemical and catalytic approaches in acetalization of benzaldehyde with methanol. The investigation of basicity and Lewis acidity was done by IR spectroscopy using CDCl 3 and 5-nonanone as probe molecules, respectively. The combination of physicochemical and catalytic investigations demonstrates that acid–base and catalytic properties of these materials depend on amount and type of functional groups presented in the linker units. Insertion of electron-donating NH 2 -groups into linker ligand leads to increase in the strength of basic sites in contrast to electron-withdrawing NO 2 -groups. The strength of Lewis acid sites decreases in order of UiO-66-NO 2 > UiO-66 > UiO-66-NH 2 , that leads to the decrease in their catalytic activity in acetalization of benzaldehyde with methanol in the same order.
99 citations
TL;DR: A series of stable carbenes, featuring a broad range of electronic properties, were reacted with simple organic substrates and found that NHCs are known to promote the benzoin condensation, and it is found that the CAAC, pyr-NHC, and ADAC react with benzaldehyde to give the ketone tautomer of the Breslow intermediate.
Abstract: A series of stable carbenes, featuring a broad range of electronic properties, were reacted with simple organic substrates. The N,N-dimesityl imidazolylidene (NHC) does not react with isocyanides, whereas anti-Bredt di(amino)carbene (pyr-NHC), cyclic (alkyl)(amino)carbene (CAAC), acyclic di(amino)carbene (ADAC), and acyclic (alkyl)(amino)carbene (AAAC) give rise to the corresponding ketenimines. NHCs are known to promote the benzoin condensation, and we found that the CAAC, pyr-NHC, and ADAC react with benzaldehyde to give the ketone tautomer of the Breslow intermediate, whereas the AAAC first gives the corresponding epoxide and ultimately the Breslow intermediate, which can be isolated. Addition of excess benzaldehyde to the latter does not lead to benzoin but to a stable 1,3-dioxolane. Depending on the electronic properties of carbenes, different products are also obtained with methyl acrylate as a substrate. The critical role of the carbene electrophilicity on the outcome of reactions is discussed.
90 citations
TL;DR: The catalysts were extremely active, selective, and stable for oxidative esterification of benzyl alcohol to methyl benzoate, benzene hydrogenation to cyclohexane, and oxidation of benzinyl alcohol to benzaldehyde because they combined the advantages of the nanocatalysts of small size and hierarchical porosity of the supports.
Abstract: Stable porous ionic liquid-water gel induced by inorganic salts was created for the first time. The porous gel was used to develop a one-step method to synthesize supported metal nanocatalysts. Au/SiO2, Ru/SiO2, Pd/Cu(2-pymo)2 metal–organic framework (Cu-MOF), and Au/polyacrylamide (PAM) were synthesized, in which the supports had hierarchical meso- and macropores, the size of the metal nanocatalysts could be very small (<1 nm), and the size distribution was very narrow even when the metal loading amount was as high as 8 wt %. The catalysts were extremely active, selective, and stable for oxidative esterification of benzyl alcohol to methyl benzoate, benzene hydrogenation to cyclohexane, and oxidation of benzyl alcohol to benzaldehyde because they combined the advantages of the nanocatalysts of small size and hierarchical porosity of the supports. In addition, this method is very simple.
87 citations
TL;DR: Morpholinone- and piperidinone-derived triazolium salts are shown to catalyze highly chemoselective cross-benzoin reactions between aliphatic and aromatic aldehydes.
Abstract: Morpholinone- and piperidinone-derived triazolium salts are shown to catalyze highly chemoselective cross-benzoin reactions between aliphatic and aromatic aldehydes. The reaction scope includes ortho-, meta-, and para-substituted benzaldehyde derivatives with a range of electron-donating and -withdrawing groups as well as branched and unbranched aliphatic aldehydes. Catalytic loadings as low as 5 mol % give excellent yields in these reactions (up to 99%).
84 citations
TL;DR: In this article, a new Pd-substituted octahedral molecular sieve (Pd/K-OMS-2) was prepared for the direct amination of alcohols with primary amines operating under the borrowing hydrogen mechanism.
83 citations
TL;DR: In this article, experiments were conducted on the liquid-phase oxidation of benzyl alcohol over Pd nanoparticles, with the aim of determining the operative chemical reaction, and it was determined that there are two primary reaction paths: an alkoxy pathway leading to toluene, benzaldehyde, and benzyl ether, and a carbonyloxyl pathway (neutral carboxylate) leading to benzoic acid, benzene, and benyl benzoate.
Abstract: Experiments were conducted on the liquid-phase oxidation of benzyl alcohol over Pd nanoparticles, with the aim of determining the operative chemical reaction. Experiments were conducted in a batch reactor with para-xylene as the solvent and continuous gas purging of the headspace. The following experimental parameters were varied: the initial benzyl alcohol concentration, the oxygen partial pressure in the headspace, and the reactor temperature. From trends in the concentration profiles and integrated production of each product, it was determined that there are two primary reaction paths: A) an alkoxy pathway leading to toluene, benzaldehyde, and benzyl ether, and B) a carbonyloxyl pathway (“neutral carboxylate”) leading to benzoic acid, benzene, and benzyl benzoate. From the mechanism elucidated, it is clear that the coverages of atomic hydrogen, atomic oxygen, and surface hydroxyls must be accounted for to achieve a complete description of the quantitative kinetics.
TL;DR: In this paper, a modification of graphitic carbon nitride photocatalyst with acid was accomplished with a facile method through reflux in different acidic substances, which improved surface area, reduced structural size, enlarged band gap, enhanced surface chemical state, and facilitated photoinduced charge separation, contributing to the enhanced photocatalytic activity.
TL;DR: In this paper, a facile and eco-friendly way based on the simultaneous bioreduction of HAuCl4 and Na2PdCl4 with ascorbic acid and Cacumen Platycladi leaf extract at room temperature was presented.
Abstract: ∼40 nm flower-shaped Au–Pd bimetallic nanoparticles were prepared in a facile and eco-friendly way based on the simultaneous bioreduction of HAuCl4 and Na2PdCl4 with ascorbic acid and Cacumen Platycladi leaf extract at room temperature. Characterization techniques, such as transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction, were employed to confirm that the as-synthesized nanoparticles were alloys. The obtained flower-shaped Au–Pd alloy nanoparticles exhibited an excellent surface enhanced Raman spectroscopic activity with rhodamine 6G and efficient catalytic ability for the oxidation of benzyl alcohol to benzaldehyde.
TL;DR: Light-driven dehydrogenation of benzyl alcohol to benzaldehyde and hydrogen has been shown to occur in a dye-sensitized photoelectrosynthesis cell (DSPEC) and the nanoITO/TiO2 core/shell structure causes a decrease of up to 2 orders of magnitude in back electron-transfer rate compared to TiO2.
Abstract: Light-driven dehydrogenation of benzyl alcohol (BnOH) to benzaldehyde and hydrogen has been shown to occur in a dye-sensitized photoelectrosynthesis cell (DSPEC). In the DSPEC, the photoanode consists of mesoporous films of TiO2 nanoparticles or of core/shell nanoparticles with tin-doped In2O3 nanoparticle (nanoITO) cores and thin layers of TiO2 deposited by atomic layer deposition (nanoITO/TiO2). Metal oxide surfaces were coderivatized with both a ruthenium polypyridyl chromophore in excess and an oxidation catalyst. Chromophore excitation and electron injection were followed by cross-surface electron-transfer activation of the catalyst to −RuIV═O2+, which then oxidizes benzyl alcohol to benzaldehyde. The injected electrons are transferred to a Pt electrode for H2 production. The nanoITO/TiO2 core/shell structure causes a decrease of up to 2 orders of magnitude in back electron-transfer rate compared to TiO2. At the optimized shell thickness, sustained absorbed photon to current efficiency of 3.7% was ac...
TL;DR: In this article, the authors used SBA-15 catalysts with different Ag contents for the gas-phase selective oxidation of benzyl alcohol to benzaldehyde with O2 as the oxidant.
TL;DR: Differently modified TiO2 nanotubes were used to achieve a drastic change in the selectivity of a photocatalytic reaction, and certain undesired reaction pathways can be completely shut down.
Abstract: Differently modified TiO2 nanotubes were used to achieve a drastic change in the selectivity of a photocatalytic reaction. For the photocatalytic oxidation of toluene, depending on the electronic properties of TiO2 (anatase, rutile, Ru-doped), a strong change in the main reaction product (namely benzoic acid versus benzaldehyde) can be achieved, and certain undesired reaction pathways can be completely shut down.
TL;DR: In this article, the selectivity of aerobic oxidation of benzyl alcohol with gold nanoparticles dispersed on Al2O3 support is solvent-controlled using different solvents, and the reaction was directed toward a variety of products: benzaldehyde, benzoic acid or benzic esters were selectively produced from benzyl ethanol depending on the conditions.
Abstract: As shown herein, selectivity of aerobic oxidation of benzyl alcohol with gold nanoparticles dispersed on Al2O3 support is solvent-controlled. Using different solvents, the reaction was directed toward a variety of products: benzaldehyde, benzoic acid or benzoic esters were selectively produced from benzyl alcohol depending on the conditions. In toluene, benzaldehyde was produced with high selectivity, while quantitative conversion to benzoic acid was achieved in alkaline water. In methanol, methyl benzoate was produced with very high yield. Moreover, activity of the catalyst was dramatically improved without loss of selectivity in biphasic media; with a toluene/alkaline water system the highest TOF for benzoic acid synthesis was close to 5200 h−1, selectivity being 98%.
TL;DR: In this paper, a series of isostructural 3D metal-organic frameworks of 2,5-dihydroxyterephthalate with different metal ions, CPO-27-M (or MOF-74-M, M = Co, Mg, Mn, Ni and Zn), have been studied as catalysts for cyanosilylation of aldehydes with trimethylsilylcyanide and oxidation of styrene with tert-butylhydroperoxide.
Abstract: A series of isostructural 3D metal–organic frameworks of 2,5-dihydroxyterephthalate with different metal ions, CPO-27-M (or MOF-74-M, M = Co, Mg, Mn, Ni and Zn), have been studied as catalysts for cyanosilylation of aldehydes with trimethylsilylcyanide and oxidation of styrene with tert-butylhydroperoxide, and two mixed-metal Co-Mn MOFs also studied for cyanosilylation. All these MOFs are active in promoting cyanosilylation, but for styrene oxidation, only the Co and Mn MOFs are active while the others behave as initiators rather than catalysts. For both reactions, CPO-27-Mn exhibits the highest activity, and the catalytic processes are heterogeneous. Radical mechanisms were proposed for the styrene oxidation over CPO-27-Mn, which yields styrene oxide, benzaldehyde and a minor amount of phenylacetaldehyde. The cyanosilylation over CPO-27-Mn shows size selectivity towards aldehyde substrates, and the catalyst can be recycled without losing its structural integrity and catalytic activity. It is also recyclable for styrene oxidation, though the structure changes after the catalytic reaction.
TL;DR: In this article, a facile one-pot synthetic strategy was developed to prepare Ag/WO3 nanostructure materials with different morphologies using a cationic surfactant, cetyltrimethylammonium bromide.
Abstract: We have developed a facile one-pot synthetic strategy to prepare Ag/WO3 nanostructure materials with different morphologies using a cationic surfactant, cetyltrimethylammonium bromide. These materials were employed as catalysts in the direct synthesis of toluene to benzaldehyde using H2O2. The morphology of the Ag/WO3 materials can be varied by changing the synthesis parameters. The size and shape of the Ag/WO3 nanostructure catalyst has direct influence on the toluene conversion and benzaldehyde selectivity. The effect of different reaction parameters like reaction temperature, H2O2 to toluene molar ratio, reaction time, and so forth have been studied in detail. The Ag/WO3 catalyst with ∼7 nm silver nanoparticles on the WO3 nanorod with a diameter ∼60 nm showed the best catalytic activity of 42% toluene conversion with 93% benzaldehyde selectivity. The catalyst did not show any leaching up to four reuses, showing the true heterogeneity of the catalyst.
TL;DR: Belt-shaped molybdenum carbides in α- and β-phases were synthesized by reducing and carburizing a nano-sized α-MoO3 precursor with hydrocarbon-hydrogen mixtures at appropriate temperatures; the β-Mo2C nanobelts with a higher fraction of coordinatively unsaturated Mo sites were more active in dehydrogenation of benzyl alcohol to benzaldehyde
TL;DR: In this article, a gram-scale synthesis of 3-[(E)-2-(7-chloroquinolin-2-yl)vinyl]benzaldehyde, a key intermediate of leukotriene receptor antagonist (Montelukast), was demonstrated.
Abstract: Bioactive azaarene-substituted lactic acids, β-hydroxy esters, 3-hydroxy-2H-indol-2-ones, and 2-alkenylazaarenes were prepared in moderate-to-excellent yields via C(sp3)–H functionalization of methyl azaarenes with carbonyl compounds in the presence of iron(II) acetate as an inexpensive, nontoxic, efficient catalyst. The application of this atom-, step-economic, and environmentally friendly method was demonstrated by a gram-scale synthesis of 3-[(E)-2-(7-chloroquinolin-2-yl)vinyl]benzaldehyde, a key intermediate of leukotriene receptor antagonist (Montelukast).
TL;DR: In this paper, a deposition-precipitation (DP) method was used to extract supported gold nanoparticles (NPs) from the commercial MgO through the DP method and characterized by XRD, XPS, HRTEM, FTIR spectroscopy and N 2 adsorption techniques.
Abstract: Magnesium oxide and magnesium hydroxide materials containing supported gold nanoparticles (NPs), Au/Mg(OH) 2 and Au/MgO, were prepared from the commercial MgO through the deposition–precipitation (DP) method and characterized by XRD, XPS, HRTEM, FTIR spectroscopy and N 2 adsorption techniques. It was found that the starting MgO support was fully transformed into the Mg(OH) 2 phase during the DP procedure. A nearly complete dehydration of the magnesium hydroxide and formation of Au/MgO was achieved through the reductive treatment at 500 °C, whereas the treatment at 350 °C still resulted in the Au/Mg(OH) 2 material. The FTIR analysis showed a much higher ability of the Au/MgO surface to adsorb both benzyl alcohol and benzaldehyde (ca. 10 and 3 times, respectively), as compared to Au/Mg(OH) 2 . Probably for this reason, the Au/MgO catalyst exhibited ca. 50% higher catalytic activity in the aerobic oxidation/oxidative methoxylation of benzyl alcohol in the methanol solutions with respect to the amount of surface gold atoms as compared to the Au/Mg(OH) 2 catalyst, in spite of a larger size of the Au NPs. In addition, the thermal treatment of the catalyst at 500 °C to dehydrate the support allowed to suppress the undesired side reaction between benzyl alcohol and primarily formed benzaldehyde to give benzyl benzoate.
TL;DR: Hollow iron oxide nanoshells are active, selective and recyclable catalysts for the oxidation of styrene into benzaldehyde using difficult-to-activate molecular oxygen as the sole oxidant.
TL;DR: In this paper, a TEMPO-containing catalytic system was used to achieve a 99% conversion and 94% selectivity for benzaldehyde in the absence of base/acid, and the effects of quaternary ammonium salts and anionic surfactants were investigated.
TL;DR: In this paper, the authors present two strategies that can be used to switch off the formation of the non desired toluene in a solvent-free benzyl alcohol to benzaldehyde using supported gold palladium nanoparticles as catalysts.
TL;DR: In this article, the electrocatalytic activity of PPy-TEMPO for benzyl alcohol in NaClO 4 -CH 3 CN solution is investigated by cyclic voltammetry and in situ FTIR.
TL;DR: The M-TiO2 catalysts showed catalytic activities for the oxidation of benzyl alcohol and toluene to generate chlorine-free benzaldehyde in excellent selectivities (>99%) and the product distribution of styrene oxidation experienced a reverse trend.
Abstract: A series of metal ion doped TiO2 nanoparticles (M–TiO2, M = Cr3+, Mn2+, Fe3+, V5+, Zn2+, Ni2+, Ag+, Cu2+ and Co2+) were prepared by a facile co-precipitation approach and characterized by means of ICP-AES, N2 adsorption–desorption isotherms, XRD, TEM and HRTEM. Their catalytic performance was investigated via the oxidation of organic compounds. The variation of metal ion species and doping contents allowed tuning the catalytic properties of the M–TiO2. Among them, the catalyst Cu-10 displayed excellent activity (97.5%) in the oxidation of styrene and the selectivity of benzaldehyde was as high as 99.4%. Surprisingly, the product distribution of styrene oxidation experienced a reverse trend over the Co–TiO2 catalysts with different doping amounts of cobalt ions: Co-10 was in favor of forming benzaldehyde (80.2% selectivity), in contrast with Co-15, which produced styrene oxide as the dominant product (84.7% selectivity). The M–TiO2 catalysts also showed catalytic activities for the oxidation of benzyl alcohol and toluene to generate chlorine-free benzaldehyde in excellent selectivities (>99%).
TL;DR: Ruthenium encapsulated in an aluminium oxyhydroxide-support was investigated for the transfer hydrogenation of aldehydes and ketones with potassium formate as a sustainable green hydrogen donor as discussed by the authors.
Abstract: Ruthenium encapsulated in an aluminium oxyhydroxide-support was investigated for the transfer hydrogenation of aldehydes and ketones with potassium formate as a sustainable green hydrogen donor. The entrapped ruthenium were narrowly distributed with mean diameters of 1.5–1.8 nm. XPS studies show that the ruthenium was present as Ru 0 and Ru 3+ . The catalysts showed high activity even at low metal loadings of 0.5–2 wt.%. The maximum TOF for benzaldehyde hydrogenation was over 1 wt.% Ru. The reduction of aromatic and aliphatic aldehydes was facile and occurred with 100% yield. In comparison, ketones were less readily reduced although moderate to excellent yields could be obtained after a longer reaction time. No leaching of ruthenium was observed in contrast to a catalyst prepared by wet impregnation. Washing of the used catalyst with water and ethanol effectively removed the deposited bicarbonate co-product and the recycled catalyst maintained its activity up to five runs.
TL;DR: In this paper, the presence of a basic potassium salt (K2CO3 or KF) suppresses this inhibition, but promotes the formation of benzyl benzoate from the alcohol and aldehyde.
Abstract: Benzyl alcohol oxidation was carried out in toluene as solvent, in the presence of the potentially inhibiting oxidation products benzaldehyde and benzoic acid. Benzoic acid, or a product of benzoic acid, is identified to be the inhibiting species. The presence of a basic potassium salt (K2CO3 or KF) suppresses this inhibition, but promotes the formation of benzyl benzoate from the alcohol and aldehyde. When a small amount of water is added together with the potassium salt, an even greater beneficial effect is observed, due to a synergistic effect with the base. A kinetic model, based on the three main reactions and four major reaction components, is presented to describe the concentration-time profiles and inhibition. The inhibition, as well as the effect of the base, was captured in the kinetic model, by combining strong benzoic acid adsorption and competitive adsorption with benzyl alcohol. The effect of the potassium salt is accounted for in terms of neutralization of benzoic acid.
TL;DR: In this paper, the gas phase hydrogenation of benzoic acid was studied over Au supported on CeO 2 and Ce 0.62 Zr 0.38 O 2 (CZ), where the presence of Zr increased oxygen mobility, resulting in a greater degree of Ce 4+ reduction (to Ce 3+ ) in Au/CZ.