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 CD₂C(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 CD₂CH–CH₃ and CD₂C(CH₃)₂ implies that π-allylic species with partial carbonium ion character are the intermediates in isomerization in the absence of water or alcohol.