Structure and reaction pathways of methyl lactate on Pd(1 1 1)

The adsorption and reaction of methyl lactate (CH 3CH(OH)COOCH 3) is studied in ultrahigh vacuum on a Pd(1 1 1) surface using temperature-programmed desorption (TPD) and reflection–absorption infrared spectroscopy (RAIRS). Methyl lactate reacts at relatively low temperatures (∼220 K) by O–H bond scission. This intermediate can either react with hydrogen to reform methyl lactate at ∼280–300 K or undergo β-hydride elimination to form flat-lying methyl pyruvate. This decomposes to form acetyl and methoxy carbonyl species as found previously following methyl pyruvate adsorption on Pd(1 1 1). These species predominantly react to form carbon monoxide, methane and hydrogen.