Kinetics and mechanisms of alcohol dehydration pathways on alumina materials

The steady state rates of ethene and diethyl ether formation in parallel ethanol dehydration reactions at 573 and 623 K are mechanistically and kinetically described by the same rate expression on different alumina materials (-, -, and -Al 2 O 3 ), implying that alumina materials have similar surface sites under reaction environments. In situ chemical titration using pyridine as a titrant elucidates similar site densities (0.12 sites nm 2 and 0.07 sites nm 2 for ethene formation and 0.14 sites nm 2 and 0.09 sites nm 2 for diethyl ether formation on - and -Al 2 O 3 , respectively) on - and -Al 2 O 3 indicating that similar surface features exist on both - and -Al 2 O 3 . Pyridine-ethanol co-feed experiments show that pyridine inhibited the formation of ethene to a greater extent than diethyl ether suggesting that the two parallel dehydration reactions are not catalyzed by a common active site. Ethanol dehydration on ,,-alumina mechanistically and kinetically described by the same rate expression implicating similar active sites on all alumina materials.