Synthesis of ketenes from carboxylic acids on functionalized silica monoliths at short contact times

We have synthesized ketene and dimethylketene by dehydration of acetic acid and isobutyric acid, respectively, over functionalized silica monoliths at contact times of 10 to 100 ms. Molar yields of ketene and dimethylketene o f 79 and 87% per pass, respectively, are routinely achieved. These results indicate that the control of contact time is a valid strategy for maximizin g yield in catalytic ketene synthesis. (C) 2000 Elsevier Science B.V. All r ights reserved.