Exchange reaction of formate with gas-phase acetic acid on Ni(110)

The exchange reaction of formate with gas-phase acetic acid on Ni(110) was studied by time resolved infrared reflection absorption spectroscopy. It wa s found that the preadsorbed for mate was replaced ill the acetate by the i ntroduction of acetic acid on formate-full covered Ni(110), originated from the post-exposed acetic acid. Acetate was also replaced in formate by the introduction of formic acid on acetate-full covered Ni(110). These exchange reactions took place from 240 to 300 K, where decomposition of neither for mate nor acetate was observed. Thus, it was confirmed that the preadsorbed formate or acetate was desorbed as formic or acetic acid accompanied by the transfer of hydrogen atoms from post-introduced acetic or formic acid. The activation energy of the exchange reaction of formate with post-introduced acetic acid was estimated to be 17 +/- 2 kJ mol(-1). The small activation energy of the exchange reaction is discussed on the basis of adsorption ass isted desorption. (C) 1999 Elsevier Science B.V. All rights reserved.