Hydrogenation of Amino Acid Mixtures to Amino Alcohols

Amino alcohols are important building blocks for a variety of pharmaceutical, insecticidal, and other specialty compounds. Hydrogenation of amino acids to amino alcohols is a route that allows for the incorporation of biorenewable-derived chemicals into traditional petroleum-based industrial processes. This study examines the effect of multiple substrates on aqueous-phase hydrogenation rates of the amino acids serine, alanine, and valine. Hydrogenation reactions were carried out in a high-pressure reactor at 7.0 MPa hydrogen pressure and 130 °C over carbon supported ruthenium catalyst. Samples taken at regular intervals and analyzed by high-performance liquid chromatography allowed calculation of conversion rates and product yields. In general, competition between the amino acid substrates results in reduced reaction rates relative to that for hydrogenation of a single amino acid substrate. Kinetics of mixed amino acid hydrogenation was modeled using a Langmuir−Hinshelwood-type mechanism with surface reaction as the rate-limiting step.