Applications of Solid-State NMR in Oil Shale Research

Abstract

Solid-state 13 C NMR techniques provide a powerful means to obtain information about the carbon structure of fossil fuel materials. This chapter describes the solid-state NMR and its applications to the study of oil shales and emphasizes on the applications of 13 C NMR; however, some 1 H NMR studies are also included in this chapter. The chapter also presents examples from oil shale studies to illustrate these concepts. In most forms of spectroscopy, sensitivity and resolution are the primary concerns and is particularly true for the observation of 13 C NMR spectra in solids, such as oil shales. The chapter also discusses some major problems that must be overcome to acquire NMR spectra to obtain useful information about the carbon structure of the organic matter in oil shales, including the 1 H- 13 C dipole-dipole interaction and the chemical shift anisotropy. Solid-state NMR measurements are now made routinely in fossil fuel research, particularly in coal structure studies. For oil shales, solid-state NMR methods are particularly useful because the measurements can be made on raw shale, without the need to remove the mineral matter. However, because of the reduced emphasis in developing oil shale deposits commercially, the applications of NMR in oil shale research are now not as common as was in the past.