Accession Number : AD0613240

Title :   ACID-BASE CATALYSIS IN CONCENTRATED ACID SOLUTION. DEUTERIUM ISOTOPE EFFECTS IN THE DECARBONYLATION OF AROMATIC ALDEHYDES,

Corporate Author : WASHINGTON UNIV SEATTLE

Personal Author(s) : Shubert,W. M. ; Burkett,Howard

Report Date : 16 MAY 1955

Pagination or Media Count : 5

Abstract : Isotope effects have been determined for (1) the decarbonylation of mesitaldehyde vs. deuteromesitaldehyde (MesCDO) in 60 to 100% sulfuric acid, and (2) the decarbonylation of mesitaldehyde in 60 to 100% sulfuric vs. deuterosulfuric acid. The observed isotope effects are not explained by a termolecular mechanism. With certain reasonable assumptions, a bimolecular mechanism of successive proton transfer steps, equations 2 and 3, is consistent with the isotope effects. All previous observations are explainable on the basis of the bimolecular mechanism, including (1) the shapes of the plots of k(obsd) vs. % sulfuric acid for 2,4,6-trimethyl-, triethyl- and triisopropylbenzaldehyde, and (2) the fact that for the mesitaldehyde decarbonylation, the change in k(obsd) with sulfuric acid percentage is in apparent agreement with the unimolecular mechanism, 4, over part of the acid range. (Author)

Descriptors :   (*ALDEHYDES, SULFURIC ACID), (*SULFURIC ACID, ALDEHYDES), DEUTERIUM COMPOUNDS, CATALYSIS, AROMATIC COMPOUNDS, REACTION KINETICS

Distribution Statement : APPROVED FOR PUBLIC RELEASE