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Title: Para-Hydrogen-Enhanced Gas-Phase Magnetic Resonance Imaging

Herein, we demonstrate magnetic resonance imaging (MRI) inthe gas phase using para-hydrogen (p-H2)-induced polarization. A reactantmixture of H2 enriched in the paraspin state and propylene gas is flowedthrough a reactor cell containing a heterogenized catalyst, Wilkinson'scatalyst immobilized on modified silica gel. The hydrogenation product,propane gas, is transferred to the NMR magnet and is spin-polarized as aresult of the ALTADENA (adiabatic longitudinal transport and dissociationengenders net alignment) effect. A polarization enhancement factor of 300relative to thermally polarized gas was observed in 1D1H NMR spectra.Enhancement was also evident in the magnetic resonance images. This isthe first demonstration of imaging a hyperpolarized gaseous productformed in a hydrogenation reaction catalyzed by a supported catalyst.This result may lead to several important applications, includingflow-through porous materials, gas-phase reaction kinetics and adsorptionstudies, and MRI in low fields, all using catalyst-free polarizedfluids.
Authors:
; ; ; ; ; ;
Publication Date:
OSTI Identifier:
923362
Report Number(s):
LBNL-63262
R&D Project: 508601; BnR: KC0203010; TRN: US200804%%1087
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Angewandte Chemie International Edition; Journal Volume: 46; Journal Issue: 22; Related Information: Journal Publication Date: 23 Apr 2007
Research Org:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Org:
USDOE Director. Office of Science. Office of Basic EnergySciences; US Department of Homeland Securities ContractDE-AC05-06OR23100; Russian Science Support foundation
Country of Publication:
United States
Language:
English
Subject:
36; ADSORPTION; ALIGNMENT; CATALYSTS; DISSOCIATION; HYDROGENATION; MAGNETIC RESONANCE; MAGNETS; MIXTURES; NMR SPECTRA; POLARIZATION; POROUS MATERIALS; PROPANE; PROPYLENE; REACTION KINETICS; REACTOR CELLS; SILICA GEL; altadena heterogeneous catalysis magnetic resonance imaging NMRpara-hydrogen induced polarization