Brønsted acidity of rutile developed during alcohol dehydration as shown by simultaneous alkene isomerization: microwave spectroscopic analyses
Abstract
Microwave spectroscopic analyses of deuteriopropenes produced from CD2CH–CH3, and of deuterioisobutenes from CD2
C(CH3)2, indicate conclusively that on rutile in the presence of water and/or alcohol carbonium ion intermediates are involved in alkene isomerization; in contrast, comparison of rates of reaction of CD2
CH–CH3 and CD2
C(CH3)2 implies that π-allylic species with partial carbonium ion character are the intermediates in isomerization in the absence of water or alcohol.