Production of Pure Aqueous 13 C‐Hyperpolarized Acetate by Heterogeneous Parahydrogen‐Induced Polarization

A supported metal catalyst was designed, characterized, and tested for aqueous phase heterogeneous hydrogenation of vinyl acetate with parahydrogen to produce 13 C‐hyperpolarized ethyl acetate for potential biomedical applications. The Rh/TiO 2 catalyst with a metal loading of 23.2 wt % produced strongly hyperpolarized 13 C‐enriched ethyl acetate‐1‐ 13 C detected at 9.4 T. An approximately 14‐fold 13 C signal enhancement was detected using circa 50 % parahydrogen gas without taking into account relaxation losses before and after polarization transfer by magnetic field cycling from nascent parahydrogen‐derived protons to 13 C nuclei. This first observation of 13 C PHIP‐hyperpolarized products over a supported metal catalyst in an aqueous medium opens up new possibilities for production of catalyst‐free aqueous solutions of nontoxic hyperpolarized contrast agents for a wide range of biomolecules amenable to the parahydrogen induced polarization by side arm hydrogenation (PHIP‐SAH) approach.