Design and construction of a reactor for in situ infrared studies of catalytic reactions

Abstract

Transmission infrared spectroscopy is a very useful technique for characterizing the structure of adsorbed species present on a catalyst under reaction conditions. Reactors for conducting such in situ studies have been described by a number of authors. The details for a very simple reactor which can be used to study catalytic reactions at moderate temperatures (<573 K) and elevated pressures are described. The reactor has a very low dead volume and a short optical path length, and is built in such a fashion that infrared windows and catalyst samples can be replaced quite easily. The reactor described here has been used to study the hydrogenation of CO at temperatures up to 573 K and pressures as high as 2.4 MPa. No problems have been encountered with either extended operation or cycling of the temperature between 373 and 573 K. The upper limit on the operating temperature is 590 K and is set by the Kalrez O-rings. The upper limit on pressure is not as clearly established.