Investigation of "Rearrangement Step" in classical Beckmann rearrangement mechanism over solid acid by means of O-18 isotopic


Autoria(s): Zhang Z; Xing JP; Li J; Yang XG
Data(s)

2007

Resumo

The reaction mechanism of the Beckmann rearrangement over B2O3/gamma-Al2O3 and TS-1 in the gas phase has been investigated by isotope labeling approach. The isotopic labeled products were measured by mass spectrometry method. By exchanging oxygen with H, 180 in the rearrangement step, it was found that the exchange reaction between cyclohexanone oxime and (H2O)-O-18 over B2O3/-gamma-Al2O3 and TS-1 could only be carried out in some extent. It suggested that the dissociation of nitrilium, over solid acids be not completely free as the classical mechanism. A concept of the dissociation degree (alpha) that is defined as the ratio of the dissociated intermediate nitrilium to the total intermediate nitrilium has been proposed. By fitting the experimental values with the calculation equation of isotopic labeled products, it is obtained that a values for B2O3/-gamma-Al2O3 and TS-1 are 0.199 and 0.806 at the reaction conditions, respectively.

Identificador

http://ir.ciac.jl.cn/handle/322003/14017

http://www.irgrid.ac.cn/handle/1471x/149779

Idioma(s)

英语

Fonte

Zhang Z;Xing JP;Li J;Yang XG.Investigation of "Rearrangement Step" in classical Beckmann rearrangement mechanism over solid acid by means of O-18 isotopic,JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL,2007 ,275(1-2):36-46

Palavras-Chave #CYCLOHEXANONE OXIME #CATALYTIC-PROPERTIES #ACTIVE-SITES #ZEOLITES
Tipo

期刊论文