Formation of cyclopentanone from dimethyl hexanedioate over CeO2

Cycloketonization of dimethyl hexanedioate into cyclopentanone was investigated over pure CeO2 at a temperature between 350 and 475 °C. The conversion of the diester increased with raising the reaction temperature. The selectivity to cyclopentanone, however, decreased whenever the conversion increased. The major by-product other than methanol was 2-methylcyclopentanone. It was found that methylation of cyclopentanone with methanol into 2-methylcyclopentanone proceeded over CeO2. The decrease in the selectivity to cyclopentanone at high conversion was mainly caused by a consecutive reaction of cyclopentanone into 2-methylcyclopentanone due to alkylation with methanol.