A method to evaluate hydrogen donation ability of hydrogen-storage solvent in hydrogenation process by radical-precursor compounds

Abstract

Hydrogen storage using organic solvent has attracted worldwide attention. Such solvents, generally named hydrogen storage solvent (HS), are expected to release H2 but can also be used directly in hydrogenation reactions. Hydrogen donation capacity (QHS-H) and initial hydrogen donation temperature (Ti) of HSs are important parameters in hydrogenation reaction. This work develops a simple method to determine these two parameters using radical-precursors (RP) containing weak covalent bonds. The test is carried out in an ambient-pressure glass microreactor system. The idea is estimating QHS-H by the amount of hydrogen obtained by RPs (QRP+H) and determining Ti by the first-order kinetics of RP hydrogenation reaction. Reliability of the method is verified by evaluating QHS-H of the structure–known HSs, 9,10-dihydrophenanthrene (DHP), 9,10-dihydroanthracene (DHA) and tetralin (THN) with benzyl phenyl ether (BPE) and bibenzyl (BBZ) as the RPs. Results show that QRP+H is close to QHS-H, and the p-value of F-test is higher than 0.05 at a confidence level of 95%. The Ti can be determined by the first-order kinetics of BPE hydrogenation.