Synthesis Of Benzaldehyde Research Articles

Surfactants govern the fabrication of sulfur-enriched heterojunction catalysts for highly selective photocatalytic conversion of toluene

Photocatalytic selective oxidation of toluene represents a milder and more environmentally friendly strategy for the synthesis of benzaldehyde. In order to enhance catalytic performance, efficient carrier separation and transport are crucial in the photocatalytic process. This study focused on the preparation of ZnS@ZnIn2S4 with sulfur vacancies and heterostructures, combining the advantages properties of ZnS and ZnIn2S4 in photocatalysis. The effects of ZnS and surfactants on the catalytic properties of the composites were studied in depth. Characterization tests revealed that surfactant-modified ZnS@ZnIn2S4 exhibited a higher concentration of sulfur defects, which facilitated electron trapping and promoted photogenerated carrier separation and utilization. Additionally, the present study also demonstrated that the incorporation of ZnS and surfactants could reduce the crystal size of ZnIn2S4, thereby facilitating the exposure of additional active sites. The synergistic effect of the aforementioned advantages enabled toluene to undergo oxidation at a conversion rate of 39% in the presence of oxygen, resulting in the production of benzaldehyde with an exceptional selectivity of 92%. This finding offers valuable insights for future endeavors in designing photocatalytic C-H bond oxidation catalysts.

Performance Evaluation of Benzyl Alcohol Oxidation with tert-Butyl Hydroperoxide to Benzaldehyde Using the Response Surface Methodology, Artificial Neural Network, and Adaptive Neuro-Fuzzy Inference System Model.

The adaptive neuro-fuzzy inference system (ANFIS), central composite experimental design (CCD)-response surface methodology (RSM), and artificial neural network (ANN) are used to model the oxidation of benzyl alcohol using the tert-butyl hydroperoxide (TBHP) oxidant to selectively yield benzaldehyde over a mesoporous ceria-zirconia catalyst. Characterization reveals that the produced catalyst has hysteresis loops, a sponge-like structure, and structurally induced reactivity. Three independent variables were taken into consideration while analyzing the ANN, RSM, and ANFIS models: the amount of catalyst (A), reaction temperature (B), and reaction time (C). With the application of optimum conditions, along with a constant (45 mmol) TBHP oxidant amount, (30 mmol) benzyl alcohol amount, and rigorous refluxing of 450 rpm, a maximum optimal benzaldehyde yield of 98.4% was obtained. To examine the acceptability of the models, further sensitivity studies including statistical error functions, analysis of variance (ANOVA) results, and the lack-of-fit test, among others, were employed. The obtained results show that the ANFIS model is the most suited to predicting benzaldehyde yield, followed by RSM. Green chemistry matrix calculations for the reaction reveal lower values of the E-factor (1.57), mass intensity (MI, 2.57), and mass productivity (MP, 38%), which are highly desirable for green and sustainable reactions. Therefore, utilizing a ceria-zirconia catalyst synthesized via the inverse micelle method for the oxidation of benzyl alcohol provides a green and sustainable methodology for the synthesis of benzaldehyde under mild conditions.

Facile hydrothermal synthesis of VO2 nanosheets as robust catalysts for liquid-phase selective oxidation of benzyl alcohol under atmospheric O2

The liquid-phase selective oxidation of benzyl alcohol is a sustainable route for the synthesis of benzaldehyde. Wherein, the exploration of heterogeneous and cheap metal oxide catalysts instead of noble metal...

Catalytic Hydrogenation Property of Methyl Benzoate to Benzyl Aldehyde over Manganese-Based Catalysts with Appropriate Oxygen Vacancies

The synthesis of benzaldehyde, a compound widely utilized in food, medicine, and cosmetics, was achieved through a one-step catalytic hydrogenation using the cost-effective raw material, methyl benzoate. This process aligns with the principles of atom economy and green production. Despite the development of numerous high-performance catalysts by scholars, the challenge remains in achieving lower reaction temperatures, ideally below 400 °C. In this study, a series of MnOx/γ-Al2O3 catalysts were meticulously prepared using the precipitation-impregnation method. These catalysts featured supports calcined at various temperatures and distinct manganese active components. Characterization techniques such as X-ray diffraction (XRD), N2 physical adsorption, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), H2 temperature programmed reduction (H2-TPR), and NH3 temperature-programmed desorption (NH3-TPD) were employed to analyze the structure and surface properties of the catalysts. Notably, the optimized reaction temperature was found to be 360 °C. The catalyst exhibited the most favorable performance when the calcination temperature of the support was 500 °C and the Mn/Al molar ratio reached 0.18. Under these conditions, the catalyst demonstrated the most suitable oxygen vacancy concentration, yielding impressive results: a conversion rate of 87.90% and a benzaldehyde selectivity of 86.1%. These achievements were attained at 360 °C, atmospheric pressure, a hydrogen to methyl benzoate molar ratio of 40:1, and a Gas Hourly Space Velocity (GHSV) of 800 h−1. This research underscores the potential for optimizing catalysts to enhance the efficiency and sustainability of benzaldehyde synthesis.

Solvent‐Free Selective Oxidation of Benzyl Alcohol at Atmospheric Pressure Catalyzed by Pd Nanoparticles Supported on g‐C3N4 Materials with Tunable Nitrogen Distributions

AbstractSolvent‐free atmospheric selective oxidation of benzyl alcohol (BZA) by molecular oxygen is a promising and green process for the synthesis of benzaldehyde (BZL). Supported Pd nanoparticles have been widely reported in the catalytic selective oxidation of BZA where the activity depends on the chemical valence and dispersion of the Pd nanoparticles. Herein, a series of thermally exfoliated g‐C3N4 (eg‐C3N4) have been synthesized under various gas conditions (air/N2) and then applied as catalyst supports to load Pd nanoparticles. The physicochemical properties of the prepared Pd/eg‐C3N4 materials have been characterized by N2 adsorption–desorption, XRD, FT‐IR, UV‐vis, XPS, and TEM. Pd nanoparticles dispersed well on the supports, and the distributions of Pd and nitrogen species of the catalysts were related to the gas conditions of the supports. In the selective oxidation of BZA, 2.5Pd/eg‐C3N4‐AN catalyst afforded conversion of BZA and the selectivity to BZL of 88 % and 92 %, respectively. The metallic Pd0 species are considered the catalytic sites of Pd/eg‐C3N4 in the catalytic reaction and meanwhile, the basic Nb species of eg‐C3N4 were beneficial to the overall activity of the catalyst.

Selective liquid-phase oxidation of toluene over heterogeneous Mn@ZIF-8 derived catalyst with molecular oxygen in the solvent-free conditions

In this work, liquid-phase catalytic oxidation of toluene was carried out under solvent-free conditions, and highly selective synthesis of benzaldehyde (BAL) and benzyl alcohol (BOL) and benzoic acid (BAC) in the presence of Mn@ZIF-8 calcined material as catalyst with oxygen molecules. As a heterogeneous catalyst, the zeolitic imidazolate framework Mn@ZIF-8 derived material exhibited reasonable substrate-product selectivity (70.3% of selectivity to BAL and BOL, 95.1 % of selectivity to BAL, BOL and BAC) and conversion (6.5%) under optimum reaction conditions. The catalysts were characterized by BET-specific surface area determination, XRD, XPS, FT-IR, TG-DTG and SEM-EDS-Mapping. The results demonstrated that the catalytic capacity of the catalysts was enhanced by the good dispersion of amorphous Mn species in ZIF-8 derivatives and high specific surface area. The possible reaction pathway for the catalytic oxidation of toluene was also suggested. Maybe this method employing Mn@ZIF-8 as efficient catalyst affords a new and environmentally friendly route for the synthesis of BOL and BAL from the selective oxidation of toluene.

Active species identification in Zn and Mn-based materials for application in alcohol oxidation reactions

Surface and bulk properties and catalytic performance during benzaldehyde synthesis of inexpensive Zn modified-MnCO3 catalysts (xZnMn), prepared by impregnation method and covering a wide range of Zn loadings (1.0 wt% Zn < x < 22.6 wt% Zn) were deeply investigated for the first time. XRD, TPN2 (temperature-programmed decompositions in N2) and XPS characterization showed that different crystalline phases containing Mn and/or Zn species are present in xZnMn. In these phases Mn oxidation state changes from 2+ toward higher values (3+ and 4+ ) as Zn content increases entailing the transformation of MnCO3 to ZnMn2O4 spinel and MnOx oxides.During benzyl alcohol oxidation at mild reaction conditions using oxygen, the highest benzaldehyde yield (∼70 %) was obtained on 15.4ZnMn sample after 6 h of reaction. The superior catalytic performance of the 15.4ZnMn catalyst was attributed to a synergistic interaction of both metals.

Efficient oxidation of benzyl alcohol into benzaldehyde catalyzed by graphene oxide and reduced graphene oxide supported bimetallic Au-Sn catalysts.

A series of bimetallic and monometallic catalysts comprising Au and Sn nanoparticles loaded on graphene oxide (GO) and reduced graphene oxide (rGO) were prepared using three distinct techniques: two-step immobilization, co-immobilization, and immobilization. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), and Inductively-coupled plasma optical emission spectroscopy (ICP-OES) were used to characterize the chemical and physical properties of prepared Au-Sn bimetallic and Au or Sn monometallic nanocatalysts. The catalytic performance of the prepared nanocatalysts was evaluated in the selective oxidation of benzyl alcohol (BzOH) to benzaldehyde (BzH) using O2 as an oxidizing agent under moderate conditions. To obtain the optimal BzH yield, the experimental conditions and parameters, including the effects of the reaction time, temperature, pressure, and solvent type on BzOH oxidation, were optimized. Under optimal reaction conditions, bimetallic Au-Sn nanoparticles supported on GO (AuSn/GO-TS, 49.3%) produced a greater yield of BzH than the AuSn/rGO-TS catalysts (35.5%). The Au-Sn bimetallic catalysts were more active than the monometallic catalysts. AuSn/GO-TS and AuSn/rGO-TS prepared by the two-step immobilization method were more active than AuSn/GO-CoIM and AuSn/rGO-CoIM prepared by co-immobilization. In addition, the AuSn/GO-TS and AuSn/rGO-TS catalysts were easily separated from the mixture by centrifugation and reused at least four times without reducing the yield of BzH. These properties make Au-Sn bimetallic nanoparticles supported on GO and rGO particularly attractive for the environmentally friendly synthesis of benzaldehyde.

Dual-functional photocatalyst of CoSx/Cd0.7Zn0.3S without noble metals for efficient selective benzaldehyde synthesis coupled with H2 production

Dual-functional photocatalyst of CoSx/Cd0.7Zn0.3S without noble metals for efficient selective benzaldehyde synthesis coupled with H2 production.

A simple salt mediated electrooxidative method for the synthesis of benzaldehydes from benzyl alcohols

A mild and efficient approach for the electrochemical conversion of benzyl alcohols to benzaldehydes is reported in homogeneous medium using Carbon/Stainless Steel electrodes and NaCl as mediator with H2SO4 as supporting electrolyte. To achieve excellent product conversion, optimization of the reaction condition with various parameters was carried out in a beaker type cell. In 2 F of current density and ambient temperature, benzyl alcohols electrochemically oxidized to benzaldehydes in 90% yield. The present work demonstrates a green and sustainable route for benzaldehydes preparation and the superiority of electrochemical method for organic synthesis.

Continuous synthesis of benzaldehyde by ozonolysis of styrene in a micro-packed bed reactor

Continuous synthesis of benzaldehyde by ozonolysis of styrene in a micro-packed bed reactor

A peroxisomal heterodimeric enzyme is involved in benzaldehyde synthesis in plants

Benzaldehyde, the simplest aromatic aldehyde, is one of the most wide-spread volatiles that serves as a pollinator attractant, flavor, and antifungal compound. However, the enzyme responsible for its formation in plants remains unknown. Using a combination of in vivo stable isotope labeling, classical biochemical, proteomics and genetic approaches, we show that in petunia benzaldehyde is synthesized via the β-oxidative pathway in peroxisomes by a heterodimeric enzyme consisting of α and β subunits, which belong to the NAD(P)-binding Rossmann-fold superfamily. Both subunits are alone catalytically inactive but, when mixed in equal amounts, form an active enzyme, which exhibits strict substrate specificity towards benzoyl-CoA and uses NADPH as a cofactor. Alpha subunits can form functional heterodimers with phylogenetically distant β subunits, but not all β subunits partner with α subunits, at least in Arabidopsis. Analysis of spatial, developmental and rhythmic expression of genes encoding α and β subunits revealed that expression of the gene for the α subunit likely plays a key role in regulating benzaldehyde biosynthesis.

Green synthesis of benzaldehydes by the selective oxidation o benzyl alcohols using hexacyanoferrate (III) and bromate under phase transfer catalysis

The selective oxidation of benzyl alcohols and substituted benzyl alcohols was carried out in greener solvents like ethyl acetate and toluene by hexacyanoferrate (III) and bromate ions under phase transfer catalysis. Various phase transfer catalysts like tetrabutylphosphonium bromide, tetrabutylammonium bromide, tetrabutylammonium hydrogen sulphate, cetyltrimethylammonium bromide and tricaprylmethylmmonium chloride were used. A pinch of sodium tungstate dihydrate is added as a co-catalyst when bromate is used an oxidant and hexacyanoferrate (III) is used in presence of mineral acids. The products obtained were precipitated as their 2,4- dinitrophenylhydrazone, purified, weighed and the yield was found to be &gt; 90 %. The products were recrystallized in ethanol and analyzed by melting point and by various spectral techniques. It was proved that corresponding benzaldehydes were formed and there was no further oxidation to corresponding acids. All the catalysts were found effective in bringing out the reaction but based on yield and ease of reaction, the order of reactivity is tricaprylmethylammonium chloride &gt; tetrabutylphosphonium bromide &gt; tetrabutylammonium bromide &gt; tetrabutylammonium hydrogen sulphate &gt; cetyltrimethylammonium bromide. The selective oxidation of benzyl alcohols is very difficult to proceed in organic solvents without the aid of a phase transfer catalyst. Yield of products is found to be slightly more in ethyl acetate than that in toluene due to difference in polarity.

Selective aerobic oxidation of benzyl alcohol on inexpensive and reusable ZnO/MnCO3 catalyst

The selective synthesis of benzaldehyde (B) by oxidation of benzyl alcohol (BA) was studied at 373 K using ZnO-MnCO3 catalysts, O2 as oxidant and mild reaction conditions. An inexpensive commercial MnCO3 sample was impregnated with aqueous solutions containing different concentration of Zn2+ cations to obtain a series of ZnO-MnCO3 catalysts with 1.0–22.6 wt% Zn. Catalysts were characterized by N2 physisorption, atomic absorption spectrometry, X-ray diffraction and X-ray photoelectron spectroscopy techniques. Benzaldehyde was selectively formed during liquid phase oxidation of benzyl alcohol but the catalytic performance of the ZnO-MnCO3 materials depended on Zn loading. The maximum initial reaction rate value was measured on the most promising catalyst (15.4 wt% Zn) and a maximum of 88% benzaldehyde yield was achieved on this catalyst after 6 h of reaction using toluene as solvent. The catalytic activity of the ZnO-MnCO3 materials could be assigned to a synergistic contribution of Zn and Mn species. While the main role of ZnO would be related to its capacity to chemisorb the alcohol, the role of highly oxidized Mn surface species (mainly Mn4+) generated during catalyst preparation, is to participate in de redox mechanism involved in benzyl alcohol oxidation toward benzaldehyde. The effect of chemical nature of polar and apolar aprotic solvents was investigated during the aerobic oxidation over 15.4ZnMn. Apolar solvents, in which the oxygen solubility is higher than in the benzyl alcohol, are more suitable for the reaction. An optimum in solvent basicity requirements (hydrogen-bond-acceptance) in order to optimize the catalyst activity was found. The regeneration and reuse of the most promising catalyst were also investigated. A mild thermal treatment at 493 K in flowing air was enough to fully recover the activity of the 15.4ZnO-MnCO3 catalyst.

Selective photocatalytic synthesis of benzaldehyde in microcapillaries with immobilized carbon nitride

Photocatalysis on microfluidic reactors can be an environmental-friendly strategy to conventional chemical synthesis methods to find selective and efficient processes to produce high value-added molecules.In this work, we report for the first time a fluoropolymer microcapillary system with an immobilizedmetal-free thermal modified carbon nitride (GCN-T)catalyst. This strategy enabled a user-friendly, plug-and-plug selective chemistry using an external UV light (λ = 392 nm) and aqueous solutions. To intensify the Benzaldehyde (BAL) production, we explored the microfluidic photocatalytic conversion of Benzyl alcohol (BA). We obtained 0.20 mM of BAL using immobilized GCN-T after 2.4 min of residence time. The results were benchmarked against the same reactor using suspended catalysts and against a conventional batch reactor. Immobilized GCN performed similarly to suspended GCN in the microfluidic reactor (0.18 mM of BAL). We increase BAL yield by 9-fold after 2.4 min using suspended GCN in a microfluidic reactor comparing to a batch reactor. The stability of immobilized photocatalyst was confirmed in reuse studies where 0.20 and 0.17 mM of BAL were produced after one and four utilization runs, respectively. We anticipate this can be related to the presence of a high concentration of particles closer to the microreactor’s inner wall, allowing the effective activation of GCN particles with UV irradiation. The immobilization of the catalyst avoided its blockage in the microfluidic channels and enabled the reuse without any further separation. To the best of our knowledge, this is the first report using the microcapillary film reactor and immobilized carbon nitride for the selective photocatalytic synthesis of BAL.

Sustainable M-MOF-74 (M = Cu, Co, Zn) prepared in methanol as heterogeneous catalysts in the synthesis of benzaldehyde from styrene oxidation

Metal-Organic Framework (MOF) materials are promising heterogeneous catalysts in different areas including Fine Chemistry, mainly if they possess open metal sites and if they are nanocrystalline. In this work, a new sustainable methodology to obtain nanocrystalline M-MOF-74 materials at room temperature, without any energy input and in methanol as the unique solvent, is described. Amongst the seven divalent metal tested, pure MOF-74 phase was achieved in the case of Co, Cu and Zn (and maybe Ni), but not in the case of Mg, Mn and Cd. The formation of these MOFs is taken place as soon as the metal source (metal acetate) and the organic linker 2,5-dihydroxyterehpthalic acid are put together. The so-prepared Co- and Cu-MOF-74 (but not Zn-MOF-74) resulted to be nanocrystalline and having high external surface area and intercrystalline mesoporosity. They were tested as heterogeneous catalysts in the synthesis of benzaldehyde from styrene using tert-butylhydroperoxide as an oxidant. Different experimental parameters like reactants ratio, amount of catalysts or reaction temperature were optimized. Cu-MOF-74 gave the highest benzaldehyde yield and interestingly it maintained intact its structure after reaction, unlike the same catalyst used in some other catalytic processes under similar relatively mild conditions.

Engineering of oxygen vacancy as defect sites in silicates for removal of diverse organic pollutants and enhanced aromatic alcohol oxidation

Efficient charge separation of the generated excitonic pair upon light irradiation is a crucial step in determining the efficiency of photocatalytic activity. Oxygen vacancy sites are known to overcome poor charge segregation. Herein, a hydrothermal approach was utilized to synthesize oxygen vacancy rich Bi2SiO5 nanoparticles (BSO NPs) with superior charge separation. Halide anion incorporation resulted in generation of oxygen vacancy sites along with a preferential growth of monoclinic over tetragonal phase. This phase transformation is advantageous as the monoclinic phase shows enhanced photocatalytic activity compared to the tetragonal. The synergetic effect of halide ions and oxygen vacancy sites on the surface led to increased photocatalytic activity arising from (1) enhanced light absorption towards visible spectrum from ultraviolet, (2) reduced bandgap, (3) surge in charge migration, and (4) increased surface area of the BSO NPs. Oxygen vacancy rich halide incorporated Bi2SiO5 NPs showed up to 12 times improved photocatalytic rate over pristine towards toxic dye pollutants. Photocatalytic tetracycline degradation mechanism was also studied displaying up to 83% degradation within 180 min of solar light irradiation. In addition, the developed photocatalyst is efficient towards synthesis of benzaldehyde from benzyl alcohol with high yield up to 40% within 4 h.

Tuneable oxidation of styrene to benzaldehyde and benzoic acid over Co/ZSM-5

Tuneable synthesis of benzaldehyde and benzoic acid from solvent-free oxidation of styrene with O2 oxidant over Co/ZSM-5 prepared at 500 and 450 °C. These two catalysts exhibited high catalytic activity with selectivity, which is 96% for benzaldehyde and 95% for benzoic acid.

A highly efficient synthesis of benzaldehyde by ozonolysis of styrene in a rotating packed bed

In this study, the highly efficient procedure for the synthesis of benzaldehyde by ozonolysis of styrene in a rotating packed bed (RPB) reactor has been developed. Ozonolysis in RPB reactor (RPB-ozone) yielded significantly more benzaldehyde compared to the stirred tank reactor (STR) (97 vs. 65 %) in 15 min. Response surface methodology (RSM) was applied to optimize the simultaneous influence of experimental parameters on the yield of benzaldehyde. The relative influence of parameters on the yield of benzaldehyde decreased in the following order: O3 concentration > high gravity factor = the amount of H2O. The significant variable-variable interactions were observed between O3 concentration and high gravity factor, as well as O3 concentration and the amount of H2O. The optimized reaction conditions using RSM were: 127.27 mg/L of O3 in the gas phase, high gravity factor of 38.9 and 24.88 mL of H2O added, which yielded 97.6 % of benzaldehyde. This was very close to the theoretical value (98.2 %), indicating that RSM analysis was able to predict the yield of benzaldehyde obtained by the ozonization of styrene and provide the optimum experimental conditions. Along with this, the reaction mechanism for the ozonolysis of styrene to benzaldehyde was proposed.

The Mandelate Pathway, an Alternative to the Phenylalanine Ammonia Lyase Pathway for the Synthesis of Benzenoids in Ascomycete Yeasts.

Benzenoid-derived metabolites act as precursors for a wide variety of products involved in essential metabolic roles in eukaryotic cells. They are synthesized in plants and some fungi through the phenylalanine ammonia lyase (PAL) and tyrosine ammonia lyase (TAL) pathways. Ascomycete yeasts and animals both lack the capacity for PAL/TAL pathways, and metabolic reactions leading to benzenoid synthesis in these organisms have remained incompletely known for decades. Here, we show genomic, transcriptomic, and metabolomic evidence that yeasts use a mandelate pathway to synthesize benzenoids, with some similarities to pathways used by bacteria. We conducted feeding experiments using a synthetic fermentation medium that contained either 13C-phenylalanine or 13C-tyrosine, and, using methylbenzoylphosphonate (MBP) to inhibit benzoylformate decarboxylase, we were able to accumulate intracellular intermediates in the yeast Hanseniaspora vineae To further confirm this pathway, we tested in separate fermentation experiments three mutants with deletions in the key genes putatively proposed to form benzenoids (Saccharomyces cerevisiaearo10Δ, dld1Δ, and dld2Δ strains). Our results elucidate the mechanism of benzenoid synthesis in yeast through phenylpyruvate linked with the mandelate pathway to produce benzyl alcohol and 4-hydroxybenzaldehyde from the aromatic amino acids phenylalanine and tyrosine, as well as sugars. These results provide an explanation for the origin of the benzoquinone ring, 4-hydroxybenzoate, and suggest that Aro10p has benzoylformate and 4-hydroxybenzoylformate decarboxylase functions in yeast.IMPORTANCE We present here evidence of the existence of the mandelate pathway in yeast for the synthesis of benzenoids. The link between phenylpyruvate- and 4-hydroxyphenlypyruvate-derived compounds with the corresponding synthesis of benzaldehydes through benzoylformate decarboxylation is demonstrated. Hanseniaspora vineae was used in these studies because of its capacity to produce benzenoid derivatives at a level 2 orders of magnitude higher than that produced by Saccharomyces Contrary to what was hypothesized, neither β-oxidation derivatives nor 4-coumaric acid is an intermediate in the synthesis of yeast benzenoids. Our results might offer an answer to the long-standing question of the origin of 4-hydroxybenzoate for the synthesis of Q10 in humans.