Formation Of Benzoic Acid Research Articles

Immobilized Vitamin B 12 within nanoreactors of MCM-41 as selective catalyst for oxidation of organic substrates

The immobilized Vitamin B 12 (Vit-B 12) within the nanoreactors of MCM-41 as molecular sieves was characterized by X-ray powder diffraction (XRD), FT-IR, chemical analysis and nitrogen adsorption–desorption. XRD and N 2 adsorption–desorption isotherms showed that the well ordered hexagonal structure of MCM-41 is presented and surface area, pore volumes and pore diameters decrease after immobilization of Vit-B 12 within nanoreactors of MCM-41. It was found that Vit-B 12/MCM-41 successfully catalyzes the oxygen transfer of tert-butylhydroperoxide (TBHP) to norbornene and trans-2-hexene-1-ol and formation of the corresponding epoxides with 90% reactivity and 100% selectivity. Moreover, cyclohexane, cyclohexene and cyclohexanol are converted to the corresponding alcohols and ketones. On the other hand, styrene undergoes oxidative degradation with the formation of benzaldehyde and benzoic acid.

Reactions of Aniline with Alkali Metal Diphenylketyls and Dianions Derived from Benzophenone and Michler′s Ketone.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Oxidative Cleavage of Carbon?Carbon Triple Bond ? A Review

Oxidation of phenylacetylene with molecular oxygen led to the formation of 10 oxygen containing products along with dimerisation, oligomerisation and polymerisation products. Benzaldehyde, benzoic acid and benzoic anhydride are the main oxidation products. The autoxidation of diphenylacetylene gives benzil as the main product and its yield increases upon use of ditertiary-butylperoxide as initiator. Examination of the crude oxidation mixtures of 1-phenylalk-1-ynes revealed the presence of corresponding α-dicarbonyl compounds in small quantities along with typical products like benzil, benzoic anhydride and phenyl benzoate. Similar oxidation of 1-phenylalkan-1,2-diones also yielded benzoic acid and the lower carboxylic acids as in the case of the corresponding 1-phenyl-1-alkynes and the oxidation is faster than the corresponding acetylenes. α-Dicarbonyl compounds undergo photochemical dissociation to free radicals in diffuse daylight but a thermal dissociation under the experimental conditions is not noted. Phenylglyoxal is regarded as one of the intermediates of phenylacetylene autoxidation. The formation of benzoic acid in all cases and considerable amounts of benzil from 1-phenyl-propane-1,2-dione and 1-phenyl-butane-1,2-dione in the thermal decomposition at 130° in presence of dibenzoyl peroxide, diacetyl peroxide or di-tert-butyl peroxide using chlorohenzene as solvent show that the reactions of the type Ph-CO-CO-R + X_ → Ph-CO_ + R-CO-X (with X_ = R'-O_ or R'-CO-O_) take place during the course of autoxidation of α-diketones. The products expected from the reaction of the short lived intermediate ketocarbenes with oxygen i.e. α-dicarbonyl compounds and lower carboxylic acids, especially benzoic acid were not detected in the thermal and photochemical decomposition of α-diazoacetophcnone, α-diazopropiophenone, α-diazobutyrophenone and a-diazodesoxyhenzoin. This shows that the oxidative scission of the C≡C bond proceeds via the corresponding α-dicarbonyl compounds as intermediates and not via the corresponding oxirenes or the valence isomeric ketocarbenes.

Vapour Phase Oxidation of Acetophenone to Benzoic Acid Over Binary Oxides of V and Mo

Test data for catalytic oxidation of acetophenone into benzoic acid performed at bench scale with V 2 O 5 –MoO 3 catalyst in a continuous downflow metal reactor are presented. The process parameters such as temperature and flow rate influence the product distribution. The P 2 O 5 , B 2 O 3 and Na 2 O when used as dopant on V 2 O 5 –MoO 3 catalyst showed marked influence on activity and selectivity. An acidic catalyst like V 2 O 5 -MoO 3 –P 2 O 5 favours formation of benzoic acid while a basic catalyst like V 2 O 5 –MoO 3 –Na 2 O favours formation of benzaldehyde. The addition of Na 2 O into V 2 O 5 –MoO 3 binary oxides formed new phases (NaVMoO 6 and Na 2 V 2 Mo 3 O 15 ), which increased Arrhenius activation energy from 18.24 to 31.35 kcal mol −1

Unraveling the Surface Reactions during Liquid-Phase Oxidation of Benzyl Alcohol on Pd/Al2O3: an in Situ ATR−IR Study

The palladium-catalyzed liquid-phase reaction of benzyl alcohol to benzaldehyde was investigated in the presence and absence of oxygen by attenuated total reflection infrared (ATR-IR) spectroscopy. The 5 wt % Pd/Al2O3 catalyst was fixed in a flow-through ATR-IR cell serving as a continuous-flow reactor. The reaction conditions (cyclohexane solvent, 323 K, 1 bar) were set in the range commonly applied in the heterogeneous catalytic aerobic oxidation of alcohols. The in situ ATR-IR study of the solid-liquid interface revealed a complex reaction network, including dehydrogenation of benzyl alcohol to benzaldehyde, decarbonylation of benzaldehyde, oxidation of hydrogen and CO on Pd, and formation of benzoic acid catalyzed by both Pd and Al2O3. Continuous formation of CO and its oxidative removal by air resulted in significant steady-state CO coverage of Pd during oxidation of benzyl alcohol. Unexpectedly, benzoic acid formed already in the early stage of the reaction and adsorbed strongly (irreversibly) on the basic sites of Al2O3 and thus remained undetectable in the effluent. This observation questions the reliability of product distributions conventionally determined from the liquid phase. The occurrence of the hydrogenolysis of the C-O bond of benzyl alcohol and formation of toluene indicates that Pd was present in a reduced state (Pd0) even in the presence of oxygen, in agreement with the dehydrogenation mechanism of alcohol oxidation.

Reactions of aniline with alkali metal diphenylketyls and dianions derived from benzophenone and Michler’s ketone

Potassium diphenylketyl and benzophenone dianion react with aniline to afford N-(diphenylmethylene) aniline. Under analogous conditions, the corresponding sodium and lithium derivatives undergo disproportionation with formation of triphenylmethanol, benzoic acid, and diphenylmethanol. The condensation of potassium and sodium bis(4-dimethylaminophenyl)ketyls and salts with Michler’s ketone dianion leads to formation of N-[bis(4-dimethylaminophenyl)methylene]aniline, while lithium bis(4-dimethylaminophenyl)-ketyl and Michler’s ketone dilithium salt are reduced to bis(4-dimethylaminophenyl)methanol.

Electrocatalytic Activity of a Polypyridyl Ruthenium‐Oxo Complex Covalently Attached to a Graphite Felt Electrode.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Electrocatalytic activity of a polypyridyl ruthenium-oxo complex covalently attached to a graphite felt electrode

The complex [RuIV(tpy)(bpy)(O)]2+ grafted to a graphite felt electrode shows electrocatalytic activity toward primary and secondary alcohols. Kinetic analyses highlights the contribution of the immobilized catalyst to the oxidation of benzenemethanol to the corresponding aldehyde, whereas the formation of benzoic acid from benzaldehyde is mostly due to a direct oxidation at the graphite electrode. In contrast to the catalyst in solution, the immobilized catalyst exhibits poor activity toward compounds containing C–H bonds adjacent to unsaturated bonds.

Biotransformations of cinnamic and ferulic acid with actinomycetes

Biotransformations of cinnamic and ferulic acid catalysed by actinomycetes have been studied. A primary screening was carried out using 535 actinomycetes isolated from soil and able to grow in the presence of cinnamic (500) or ferulic acid (35). A mininiaturized procedure of biotransformation in solid medium showed that, among the strains able to metabolise the substrates, the more frequent behaviours were the degradation of cinnamic acid (often via benzoic acid formation) or transformation in cinnamamide (22 strains), while ferulic acid was mostly degraded with transient accumulation of vanillic acid in few cases. A more restricted screening (57 representative strains) was carried out in submerged cultures: strain GE 107678, identified as Streptomyces halstedii, converted cinnamic acid in cinnamamide (95% molar conversion from 2 g/l of substrate) and ferulic acid in vanillic acid (80% molar conversion from 1 g/l of substrate) with transient formation of low amounts of vanillin (0.10–0.15 g/l).

Degradation of benzyldimethylalkylammonium chloride by Aeromonas hydrophila sp. K.

The aim of this work was to study the biodegradation of benzyldimethylalkylammonium chloride (BAC) by Aeromonas hydrophila sp. K, an organism isolated from polluted soil and capable of utilizing BAC as sole source of carbon and energy. High performance liquid chromatography and gas chromatography-mass spectrometry (GC-MS) analysis was used to study BAC degradation pathway. It was shown that during BAC biodegradation, formation of benzyldimethylamine, benzylmethylamine, benzylamine, benzaldehyde and benzoic acid occurred. Formation of benzyldimethylamine as the initial metabolite suggested that the cleavage of Calkyl-N bond occurred as the first step of BAC catabolism. Liberation of benzylmethylamine and benzylamine likely resulted from subsequent demethylation reactions, followed by deamination with formation of benzaldehyde. Benzaldehyde was rapidly converted into benzoic acid, which was further degraded. Aer. hydrophila sp. K is able to degrade BAC. A degradation pathway for BAC and related compounds is proposed. These findings are significant for understanding biodegradation pathways of benzyl-containing quaternary ammonium compounds.

Oxidative cleavage of carbon-carbon triple bond - a-review

Oxidation of phenylacetylene with molecular oxygen led to the formation of 10 oxygen containing products along with dimerisation, oligomerisation and polymerisation products. Benzaldehyde, benzoic acid and benzoic anhydride are the main oxidation products. The autoxidation of diphenylacetylene gives benzil as the main product and its yield increases upon use of ditertiary-butylperoxide as initiator. Examination of the crude oxidation mixtures of 1-phenylalk-1-ynes revealed the presence of corresponding α-dicarbonyl compounds in small quantities along with typical products like benzil, benzoic anhydride and phenyl benzoate. Similar oxidation of 1-phenylalkan-1,2-diones also yielded benzoic acid and the lower carboxylic acids as in the case of the corresponding 1-phenyl-1-alkynes and the oxidation is faster than the corresponding acetylenes. α-Dicarbonyl compounds undergo photochemical dissociation to free radicals in diffuse daylight but a thermal dissociation under the experimental conditions is not noted. Phenylglyoxal is regarded as one of the intermediates of phenylacetylene autoxidation. The formation of benzoic acid in all cases and considerable amounts of benzil from 1-phenyl-propane-1,2-dione and 1-phenyl-butane-1,2-dione in the thermal decomposition at 130° in presence of dibenzoyl peroxide, diacetyl peroxide or di-tert-butyl peroxide using chlorohenzene as solvent show that the reactions of the type Ph-CO-CO-R + X_ → Ph-CO_ + R-CO-X (with X_ = R'-O_ or R'-CO-O_) take place during the course of autoxidation of α-diketones. The products expected from the reaction of the short lived intermediate ketocarbenes with oxygen i.e. α-dicarbonyl compounds and lower carboxylic acids, especially benzoic acid were not detected in the thermal and photochemical decomposition of α-diazoacetophcnone, α-diazopropiophenone, α-diazobutyrophenone and a-diazodesoxyhenzoin. This shows that the oxidative scission of the C≡C bond proceeds via the corresponding α-dicarbonyl compounds as intermediates and not via the corresponding oxirenes or the valence isomeric ketocarbenes.

Selective catalytic oxidation of benzyl alcohol and alkylbenzenes in ionic liquids

Industrially performed catalytic oxidation reactions often suffer from drawbacks such as poor conversion and selectivity due to over-oxidation, corrosive reaction media, lack of solvent and catalyst recycling, and negative environmental impact due to evaporation of the solvents. In order to provide a methodology that addresses these problems, ionic liquids have been investigated as reaction media. For the example of the oxidation of benzyl alcohol to benzaldehyde (dehydrogenation), it was shown that the palladium metal catalysed oxidation can be brought about, leading to better TOFs than those observed in dimethyl sulfoxide, with the added advantage of facile catalyst and solvent recycling. It was found that the selectivity to benzaldehyde is strongly dependent on the level of chloride ion, which leads to the formation of dibenzyl ether. Secondly, the amount of water present in the ionic liquid determines the extent of benzoic acid formation. Interestingly, ionic liquids are able to deactivate the water formed in the oxidation of benzyl alcohol and thus prevent it from further reaction to benzoic acid. The oxidation of toluene and ethylbenzene showed that the introduction of oxygen into the molecule is feasible using the same methodology.

Reactivity of monocyclic aromatic compounds under hydrothermal conditions

Monocyclic aromatic compounds (MAC) represent a significant fraction of the total organic carbon in many geologic environments such as hydrothermal systems and petroleum reservoirs, yet the factors that control their abundance in these environments remain highly uncertain. In order to evaluate whether aqueous reactions involving MAC have a significant impact on their occurrence, laboratory experiments were conducted to observe the reactivity of several simple MAC under hydrothermal conditions that included the presence of mineral redox buffers. Aqueous solutions of individual MAC were heated at 300 to 330°C and 350 bar in flexible gold reaction vessels with titanium fittings. Toluene in aqueous solution was found to gradually decompose during heating to form primarily benzene plus CO 2, indicating the decomposition proceeded by an oxidative decarboxylation pathway. The rate of this reaction was enhanced by the presence of dissolved sulfur compounds and relatively oxidizing conditions, suggesting that intermediate oxidation state sulfur compounds (such as thiosulfate or polythionates) could play a role in promoting the reaction by facilitating the transfer of electrons among reactants. Benzoic acid decomposed rapidly to benzene plus CO 2, suggesting that formation of benzoic acid is the rate-limiting step in the overall conversion of toluene to benzene. Both benzene and phenol were found to be essentially unreactive. An assessment of the reaction products was performed to evaluate whether reactions among MAC attained metastable thermodynamic equilibrium. The results of this assessment, however, were equivocal, with some observations suggesting approach to thermodynamic equilibrium while other data indicate that criteria to demonstrate equilibrium were not met. The laboratory results demonstrate that aqueous reactions can play a role in controlling the abundance of aromatic compounds in geologic environments.

Oxidative hydroxylation of benzene and toluene by nitrous oxide over Fe-containing ZSM-5 zeolites

The gas-phase partial oxidation of benzene and toluene to phenol and to cresols over Fe-containing ZSM-5 zeolites prepared by various methods was studied using N2O as oxidant. Over FeZSM-5 synthesized by either isomorphous substitution or ion exchange the phenol selectivity reached nearly 100% at 573 K, however, only 25-30% cresol (mainly p-cresol) selectivity was observed in the oxidation of toluene because of the formation of benzaldehyde and benzoic acid in the fast oxidation of the methyl group.

Photocatalytic degradation of polycarboxylic benzoic acids in UV-irradiated aqueous suspensions of titania.: Identification of intermediates and reaction pathway of the photomineralization of trimellitic acid (1,2,4-benzene tricarboxylic acid)

Three polycarboxylic (hemimellitic (Hem), trimellitic (Tri) and pyromellitic (Pyro)) acids, representative of industrial pollutants and of compounds from biomass, were degraded by heterogeneous photocatalysis. The three molecule disappearance rates followed the order Pyro>Hem>Tri. They obeyed a Langmuir–Hinshelwood mechanism. The two competitive initial steps of attack of the molecules corresponded (i) to a hydroxylation reaction induced by photogenerated OH radicals and (ii) by a decarboxylation (photo-Kolbe) reaction resulting from the direct attack of one carboxylic group by a positive photo-hole. A very careful analysis of the degradation intermediates was performed using high performance liquid chromatography (HPLC) and gas chromatograph/mass spectrometer (GC/MS), especially in the case of Tri. The loss of several carboxyl groups leading to benzoic acid formation was observed before the aromatic ring opening. Several aliphatic acidic fragments were detected, such as malonic and succinic acids. Interestingly, a condensation product was detected, which indicated that some carboxylic radicals could attack a Tri molecule and form a Pyr molecule. However, all these acid intermediates could be photodecomposed — in agreement with previous results from the laboratory — into CO2 with a complete carbon mass balance. A detailed degradation pathway could be proposed.Such a reaction demonstrated that complex aromatic water pollutants, originating either from industry or from biomass, could be totally mineralized and that they could produce clean water.

Effects of ultrasound on the formation of α-benzoylbenzyl cyanide from benzyl cyanide and alkylphenyl ketone from α-alkylbenzyl cyanide by potassium superoxide in the presence of crown ether

Ultrasound accelerates the formation of α-benzoylbenzyl cyanide and benzoic acid in the reaction of benzyl cyanide with potassium superoxide in the presence of 18-crown-6. Similarly, 4-methylbenzyl cyanide, 4-methoxybenzyl cyanide and 4-chlorobenzyl cyanide gave the corresponding α-(4-methylbenzoyl)-4-methylbenzyl cyanide, α-(4-methoxybenzoyl)-4-methoxybenzyl cyanide and α-(4-chlorobenzoyl)-4-chlorobenzyl cyanide in 25–43% isolated yields under the same reaction conditions. Benzoic, p-toluic, 4-methoxybenzoic and 4-chlorobenzoic acids were also formed in these reactions. No reaction was observed when the mixture was simply stirred. Reflux instead of sonication gave lower yields of the products. However, α-alkylbenzyl cyanide produced a high yield of the phenylalkyl ketones when stirred. Interestingly, the corresponding benzoic acid was not formed in these reactions. Possible mechanisms for the formation of α-benzoylbenzyl cyanide from benzyl cyanide and phenylalkyl ketones from α-alkylbenzyl cyanide are also proposed.

Relationship between the formation of surface species and catalyst deactivation during the gas-phase photocatalytic oxidation of toluene

Various partial oxidation products were identified on the surface of TiO 2 and an 8% SiO 2–TiO 2 binary catalyst used for the photocatalytic oxidation of gas-phase toluene. Using in situ FTIR spectroscopy, benzaldehyde and benzoic acid were identified on the surface of the deactivated photocatalysts. Additional GC/MS analysis of methanol-extracted surface species confirmed the presence of benzaldehyde and benzoic acid and detected small concentrations of benzyl alcohol. Apparently, benzaldehyde is the main partial oxidation product that is further oxidized to benzoic acid. Benzoic acid is strongly adsorbed on the surface of the catalyst. There seems to be a correlation between the accumulation of benzoic acid on the surface and catalyst deactivation. The presence of gas-phase water in the reactive mixture seems to retard the formation of benzoic acid. The SiO 2–TiO 2 photocatalyst is more active and appears to deactivate slower than TiO 2. This binary oxide is photocatalytically active even in the absence of gas-phase oxygen. It also seems to have a higher toluene adsorption capacity than TiO 2. The acidity of the different oxides was examined using FTIR spectroscopy of adsorbed pyridine. The results indicate that no pure metal oxide displays Brønsted acidity but when SiO 2 is cofumed with TiO 2, Brønsted acidity of intermediate strength is generated. The generation of new surface sites may be responsible for the increased activity. The mechanism of this promotion effect is not clearly understood and further studies are required to elucidate it.

Benzoic acid accumulation in the Pinus thunbergii callus inoculated with the pine wood nematode, Bursaphelenchus xylophilus.

Phenylacetic acid (PA), a phytotoxic product of the bacteria accompanying the virulent nematode isolate OKD-3 was detected in the callus of Pinus thunbergii after inoculation with the nematode. The amount of PA detected was large enough to induced the formation and accumulation of benzoic acid (BA) and its conjugates in the callus. These results further support the hypotheses that PA is the pathogenic toxin and that the PA-producing bacterial strains accompanying the pathogenic nematode are the genuine pathogens of the pine wilt disease.

Mass Spectrometric Evidence for the Generation of Benzyne from Benzoyl Peroxide in Thermolysis

Benzoyl peroxide gave rise to benzoic acid (at m/z 122) in its electron impact mass spectrum, and its perdeuterated counterpart produced perdeuterobenzoic acid, C6D5CO2D, at m/z 128 under the same conditions, An intramolecular hydrogen abstraction is proposed for the formation of benzoic acid from the peroxide in thermolysis. As a result of this reaction, benzyne would be generated simultaneously. Anthracene was employed to trap any of the reactive intermediate benzyne. Collision-induced dissociation of the ion of m/z 254 from the mixture of benzoyl peroxide and anthracene indicated that triptycene was obtained by the trapping reaction, therefore confirming that benzyne is generated from benzoyl peroxide in thermolysis.

Oxidation of Toluene Over V2O5-Sb2O3/TiO2 Catalysts. Enhancement of Selectivity Towards Benzoic Acid

The effect of reaction parameters, additives and cooxidants on the selectivity of toluene oxidation to benzoic acid in the vapor phase has been studied. The presence of ethanol as cooxidant in the reaction stream does not improve the selectivity of toluene oxidation towards partial oxidation products via methyl group oxidation. However, the presence of carbon dioxide has a positive effect on the selectivity to benzoic acid formation. The catalysts were characterized by temperature programmed reduction.