High‐resolution carbon‐13 nuclear magnetic resonance study of natural resins

Abstract

Developing a methodology of analysis for the identification of the components presented in natural resins without a previous isolation or treatment, we first chose to use liquid nuclear magnetic resonance(NMR) to assign the main components. However, solid-state NMR techniques give much more information about the chemical components presents in the resins than solution NMR, so we changed the methodology. The first approach must be the application of solid-state NMR techniques and continuation of the identification process by analysis of the data obtained.

Solid State NMR

“…In the solid state, the signals are broader than in solution and especially for polymers due to their high molecular weight and mere ordination, among other factors, the signals become even wider. The second point concerns the type of response to be obtained in the solid state the number of information to be obtained is greater than in solution [11][12][13][14]. However, when the material is insoluble or has soluble difficulties, the study of the structure-property relation is of great interest because the search for responses with respect to homogeneity, phase dispersion, and interaction between the components is of great importance.…”

“…Improving the resolution of the signals in the NMR spectra obtained in the solid state requires techniques to eliminate factors that cause this signal enlargement [10][11][12][13][14]. Thus, techniques were developed using methods that mathematically eliminate these effects.…”

“…Showing the highest signal located at 30.2 ppm referred to CH 2 (the methylene group) long chains and a small signal detected at 14.3 ppm attributed to the methyl group of the acetate part. Two small signals were detected at about 21 and 25 ppm, which were assigned as CH 2 from the ethylene branching [11,12].…”

“…The T 1 H relaxation time é measured in the frequency of magnetic field generated by the external magnetic field. This relaxation must do with the return of the excited nuclei to its ground state after removal of the excitation frequency, and therefore, it allows to evaluate the molecular mobility of a material, global compatibility and homogeneity, as well as processes and plasticization [1][2][3][10][11][12][13][14][15]. In this process, the excess energy is emitted to the lattice in the form of dipole interaction since there is a lowering of the enthalpy of the nuclear spin system.…”

NMR Assignment of Carbonyl and Olefinic Regions of Amescla Resin

“…Thus, the elucidation of their structure is very difficult. Many techniques have been developed to study the molecular structure of ambers (a fossilized form of terpenoid resins) [4][5][6][7][8], however, the molecular structure of the compounds of modern resins remains obscure, in spite of some efforts [9]. Some natural resins such as the amescla resins (a resin exuded from Trattinnickia burseraefolia) have no characterization study in the scientific literature.…”