Decarboxylation Of Benzoic Acid Research Articles

Unraveling the effects of the coordination number of Mn over α-MnO2 catalysts for toluene oxidation

Herein, nanorod-like α-MnO2 catalysts with 5-, 4-, and 3-coordinated Mn exposed on the surface (α-MnO2-Mn5c, α-MnO2-Mn4c, and α-MnO2-Mn3c) were employed for toluene combustion. The toluene combustion performance followed an order of α-MnO2-Mn4c > α-MnO2-Mn3c > α-MnO2-Mn5c. The effects of the coordination number of Mn over α-MnO2 catalysts for toluene oxidation were unraveled. The excellent activity of α-MnO2-Mn4c was due to stronger interactions between Mn4c with reactants and a larger amount of charge transfer from the Mn4c to the adsorbed O2, as evidenced by computational results. The results of operando diffuse reflectance infrared Fourier transform spectroscopy and gas chromatography-mass spectrometry revealed that toluene oxidation over α-MnO2 catalysts proceeded by coordination number-dependent rate-determining step. For α-MnO2-Mn4c, the rate-determining step was the cleavage of benzene species, while decarboxylation of benzoic acid was more sluggish for α-MnO2-Mn5c. These findings strongly pave a way for understanding the coordination number-induced improvement of catalytic performance of nanorod-like α-MnO2 catalysts for toluene oxidation and a deeper understanding of the mechanism of toluene degradation.

ChemInform Abstract: A Convenient Synthesis of N‐Aryl Benzamides by Rhodium‐Catalyzed ortho‐Amidation and Decarboxylation of Benzoic Acids.

The rhodium-catalyzed amidation of substituted benzoic acids with isocyanates by directed CH functionalization followed by decarboxylation to afford the corresponding N-aryl benzamides is demonstrated, in which the carboxylate serves as a unique, removable directing group. Notably, less common meta-substituted N-aryl benzamides are generated readily from more accessible para- or ortho-substituted groups by employing this strategy.

A convenient synthesis of N-aryl benzamides by rhodium-catalyzed ortho-amidation and decarboxylation of benzoic acids.

The rhodium-catalyzed amidation of substituted benzoic acids with isocyanates by directed CH functionalization followed by decarboxylation to afford the corresponding N-aryl benzamides is demonstrated, in which the carboxylate serves as a unique, removable directing group. Notably, less common meta-substituted N-aryl benzamides are generated readily from more accessible para- or ortho-substituted groups by employing this strategy.

Rhodacarboranes as catalysts for oxidative coupling of benzoic acid with diphenylacetylene

Rhodacarboranes [(9-SMe2-7,8-Me2-C2B9H8)RhCl2]2, [(1-ButNH-1,7,9-C3B8H10)-RhI2]2, [(9-SMe2-7,8-C2B9H10)Rh(C6H6)]2+, and [(7,8-R2-C2B9H9)Rh(C6H6)]+ (R = H, Me) catalyze, in the presence of Cu(OAc)2, the oxidative coupling of benzoic acid with diphenylacetylene giving 1,2,3,4-tetraphenylnaphthalene in 25–60% yields. The reactions catalyzed by RhCl3 and [CpRhI2]2 afford the product in 40 and 90% yields, respectively. The decarboxylation of benzoic acid was analyzed by DFT calculations.

ChemInform Abstract: Synthesis of Stilbene and Distyrylbenzene Derivatives Through Rhodium‐Catalyzed ortho‐Olefination and Decarboxylation of Benzoic Acids.

AbstractThe reaction proceeds highly regioselectively and the meta‐substituted stilbene derivatives are formed exclusively.

Synthesis of Stilbene and Distyrylbenzene Derivatives through Rhodium-Catalyzed Ortho-Olefination and Decarboxylation of Benzoic Acids

Ortho-substituted benzoic acids efficiently undergo precisely ordered ortho-olefination/decarboxylation upon treatment with styrenes in the presence of a rhodium catalyst and silver salt oxidant to afford the corresponding meta-substituted stilbene derivatives. The selective syntheses of 1,3- and 1,4-distyrylbenzenes have also been realized through the reactions of simple benzoic acid and phthalic acid, respectively, with styrene under similar conditions.

DISPUTE OVER BENZENE IN DRINKS

A DISPUTE HAS ERUPTED BEtween FDA and the Environmental Working Group (EWG) over whether some bottled and canned beverages contain unhealthy levels of benzene, a carcinogen. Only one issue is clear: Some drinks contain ascorbic acid (vitamin C) and the preservative sodium benzoate. In the presence of ascorbic acid under certain conditions, benzene is formed through the decarboxylation of benzoic acid ( J. Agric. FoodChem. 1993 ,41, 693). FDA first became aware of the problem in 1990 and asked manufacturers to reformulate their beverages. Between 1995 and 2001, FDA tested 24 samples of diet soda for benzene. Nineteen (79%) contained benzene at levels above the U.S. tap water standard of 5 ppb. The agency posted its analyses on a very difficult-to-access part of its website. In February of this year, EWG discovered these data and wrote to FDA expressing its concern. These results confirm our suspicions that there are highly elevated benzene levels in ...

Benzene production from decarboxylation of benzoic acid in the presence of ascorbic acid and a transition-metal catalyst

The study shows that hydroxyl radical, generated by the metal-catalysed reduction of O 2 and H 2 O 2 by ascorbic acid, can attack benzoic acid to produce benzene under condition prevalent in many foods and beverages

Reactions of di-n-butylphthalate in water at near-critical temperature and pressure

Water has a significant influence on the thermal decomposition pattern of di- n-butylphthalate (DBP) in the temperature range from 305 ° up to 390 °C and bomb water densities of up to 0.31 g cm −3. It favours hydrolytic decomposition, which results in o-phthalic acid, butanol and butene as main primary products. Subsequent reactions convert o-phthalic acid into benzoic acid and some benzene. In the absence of water the thermolysis of DBP results only in butene and a mixture of benzoic acid and benzene as the main products. Decarboxylation of benzoic acid into benzene and the formation of char appears to be strongly retarded in supercritical water. Polycondensation of phenyl species, which contributes significantly to the amount of polycondensates formed by thermolysis of DBP, is completely suppressed in supercritical water; on the contrary, polycondensation of C 4 species remains active also in supercritical water, albeit with a slower rate than in thermolysis. Butene and butanol not only consist of the 1-isomer, of which DBP is made up, but also of the 2-isomer. The latter configuration increases with the bomb water density.

A new method for the detection of hydroxyl radical production by phagocytic cells

Benzoic acid, a specific scavenger of hydroxyl radical (OH .) is known to be oxidized as the result of a reaction with OH .. We have determined that the decarboxylation of benzoic acid can be used to detect OH . generated in cell-free systems and human granulocytes. Benzoic acid is oxidized by the xanthine-xanthine oxidase enzyme system. This system is known to generate O 2 −, H 2O 2 and OH .. This oxidation is inhibited by superoxide dismutase, catalase and mannitol. Therefore, the oxidation of benzoic acid occurs by a mechanism similar to that reported for the oxidation of methional to ethylene and involves OH .. Resting granulocytes do not oxidize benzoic acid. However, marked oxidation of this substrate occurs during the phagocytosis of opsonized zymosan particles, indicating the production of OH . by these cells. The reaction can be inhibited by superoxide dismutase, catalase, azide and mannitol. Therefore, the production of OH . in the cell may be similar to that observed in the cell-free system. The granulocytes of a patient with known chronic granulomatous disease did not oxidize benzoic acid, indicating a defect in the generation of OH . by these cells.

Decarboxylation of Benzoic Acid by Hypoxylon pruinatum

Decarboxylation of Benzoic Acid by Hypoxylon pruinatum