Partial Oxidation Of Ethane Over
PARTIAL OXIDATION OF ETHANE OVER
A SUPPORTED Co CATALYSTS
N. Golub, V. Gomonay, P. Gomonay, K. Szekeresh
Uzhhorod State University
The phosphates p- and d- elements are selective catalysts of numerous processes, including in response of oxidative transformation of ethane. Aluminosilicagels can strengthen a catalytic action of such elements [1,2]. The purpose of the given work was learning catalytic properties supported on aluminosilicagel of cobalt phosphate.
The supported cobalt catalysts were prepared by adding a solution of cobalt nitrate to the aluminosilicagel support. To obtain the desired cobalt loading the concentration of the cobalt nitrate was varied accordingly. By operation of a phosphoric acid the cobalt nitrate was transferred in phosphate. The liquid phase was completely evaporated, then all of these catalysts were dried and calcined at 773 K.
It was found that the product distribution was very sensitive to experimental parameters such as the method of preparation, the type of aluminosilicagel, and the Co content.
From experiments in which the concentration of Co was varied (fig.1), it is apparent that the product distribution was strongly dependent on the Co loading. Аluminosilicagel (support without the components of a cobalt) routes
oxidation of ethane to the side of formation of formaldehyde and acids (formic and acetic). At the component even of small amounts of cobalt phosphate among products there is an alcohol ethylic. In accordance with augmentation of concentration of a cobalt phosphate in aluminosilicagel the selectivity on ethanol increases, and the selectivity on acids diminishes. At a contents about 5 % the selectivity on ethanol is maximum (70 %), and then is slowly reduced in accordance with augmentation of concentration of a cobalt. At a small contents Co (up to 5 %) the high selectivity and activity on formaldehyde is watched.
At the temperature of 773 K and residence time of reactor 1,5 s the exit of formaldehyde on ethane makes 12 %.
In accordance with augmentation of a contents of a cobalt the augmentation of a catalytic activity is watched. Is installed, that the components of a cobalt influence and light-end products of oxidation: with augmentation of a contents Co diminishes selectivity on CO and СО2. Thus cobalt inhibits formation CO and СО2 and magnifies selectivity of products of partial oxidation.
By method of a non-stationary catalysis is installed, that the alcohol will be formed not from ethane, but from ethylene. Thus, the ethylene is an intermediate product. The acetic acid will be derivated mainly from ethane.
References
1. Gomonay V., Gomonay P., Szekeresh K. Ukrain. Chem. magazine., (1998) 64, № 5, 34 (In Russian).
2. Golub N., Gomonay V., Gomonay P. and Szekeresh K (1999) Adsorption Science & Technology, 17, № 5, p. 403.
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