Importance of sequence of impregnation in the activity development of alkali-promoted mo catalysts for alcohol synthesis from CO$z.sbnd;H2

Abstract

The selective production of C/sub 2//sup +/ alcohols from CO and H/sub 2/ is of both commercial and academic interest in C/sub 1/ chemistry. The alcohol mixtures can be used as additives in gasoline to enhance the octane number. There are a number of reports on the catalysts for the synthesis of light alcohols. Synthesis of alcohols on molybdenum-based catalysts, however, was not reported until the authors discovery that mixed alcohols were efficiently produced from CO and H/sub 2/ on alkali-promoted molybdenum catalysts. Other interesting features of Mo catalysts were that they operated well in a CO-rich gas and are resistant to sulfur poisoning. In the initial study in this laboratory, catalysts were prepared by coimpregnation of SiO/sub 2/ with KCl and Mo salts. As the Mo loading was decreased, however, the authors encountered a difficulty in preparing the catalyst with good reproducibility. Hence they have employed different preparations for the Mo-K/SiO/sub 2/ catalysts. In this note they report that sequence of impregnation greatly affects the activity and selectivity. A sequence in which the K is added first, followed by impregnation with (NH/sub 4/)/sub 6/Mo/sub 7/O/sub 24/, gives rise to reproducible preparation of catalysts for alcohol production. 26 references.