Benzaldehydes formation

The kinetics of the toluene oxidation over Bi2Mo06 and a commercial Bi—Mo—P—O ammoxidation catalyst were investigated by Van der Wiele and Van den Berg [348]. A flow reactor was used at 450—550°C, 1—3 atm and varying feed rate, toluene and oxygen partial pressures. Benzaldehyde formation and combustion reactions are the main process the parallel-consecutive scheme which applies is... 

Figure 7.12. Potential energy surfaces for the o-cleavage reaction a) of acetaldehyde and b) of benzaldehyde. Formation of a bent acyl radical corresponds approximately to a reaction path along the front face OCC 130°) of the diagrams, whereas formation of the linear acyl radical proceeds on a path leading from the left front corner to the right rear corner (by permission from Reinsch and Klessinger, 1990).

Figure 3. Activity of Selected Catalysts Figure 4. Benzaldehyde Formation for...

Rhodium Catalysts. - The hydroformylation of propene with a Rh/triphenyl-phosphine catalyst is now an established industrial process which will consume over a million tonnes per annum of propene when all licensed plants are operational. Most of the product n-butyraldehyde is converted to 2-ethylhexanol for plasticiser applications. The process is also applicable to the hydroformylation of C2, C4, and C5 alkenes. The process is remarkable for the long lifetime of the Rh catalyst but by-products are formed which deactivate the catalyst and have to be removed. The formation of triphenyl-phosphine oxide, benzaldehyde, and propyldiphenylphosphine under hydroformylation conditions has been investigated where benzaldehyde is produced by or /zo-metallation of triphenylphosphine followed by CO insertion and P-C bond cleavage and propyldiphenylphosphine was assumed to result from reaction of propene with the co-ordinated diphenylphosphine group remaining after benzaldehyde formation. The same authors have also studied the kinetics of the formation of heavy by-products which are dependent on... 

Traditionally fermented dairy products have been used as beverages, meal components, and ingredients for many new products [60], The formation of flavor in fermented dairy products is a result of reactions of milk components lactose, fat, and casein. Particularly, the enzymatic degradation of proteins leads to the formation of key-flavor components that contribute to the sensory perception of the products [55], Methyl ketones are responsible for the fruity, musty, and blue cheese flavors of cheese and other dairy products. Aromatic amino acids, branched-chain amino acids, and methionine are the most relevant substrates for cheese flavor development [55]. Volatile sulfur compounds derived from methionine, such as methanethiol, dimethylsulflde, and dimethyltrisul-fide, are regarded as essential components in many cheese varieties [61], Conversion of tryptophan or phenylalanine can also lead to benzaldehyde formation. This compound, which is found in various hard- and soft-type cheeses, contributes positively to the overall flavor [57,62]. The conversion of caseins is undoubtedly the most important biochemical pathway for flavor formation in several cheese types [62,63]. A good balance between proteolysis and peptidolysis prevents the formation of bitterness in cheese [64,65],... 

Lomascolo, A., Lesage-Meessen, L., Labat, M., Navarro, D., Delattre, M., and Asther, M. (1999) Enhanced benzaldehyde formation by a monokaryotic strain of Pycnoporus cinnabarinus using a selective solid adsorbent in the culture medium. Carr J. Microbiol, 45,... 

Acidic ILs promote the benzaldehyde formation by direct carbonylation of benzene [106]. Up to 91% yield with 96% benzaldehyde selectivity was obtained with BMI-Br/AlCl3 IL. Under similar reaction conditions, using AICI3 alone as Lewis acid catalyst, benzaldehyde is formed in much lower yields (Table 6.4). 

Zeolites modified with transition metals were used as catalysts under microwave irradiation [183]. Two main dielectric mechanisms of microwave heating were determined in zeolites rotational polarization phenomenon and interfacial polarization. The selective catalytic oxidation of styrene with resulted in benzaldehyde formation. 

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