Lignin. XII.¹ The High Resolution Nuclear Magnetic Resonance Spectroscopy of Protons in Compounds Related to Lignin

Abstract

If one of these is to be associated with mechanism 16 it seems necessary to assume that IV is an intermediate in the interconversion of species I and II and that IV converts to I somewhat more rapidly than II; IV could readily convert to either of the two possible intermediates pictured above by conventional processes.

Isolation and Structure of a Dilignol Rhamnoside From the Leaves of Thuja plicata Trees

“…The chemical shift data and nature of the n.m.r. spectrum of2 is in agreement with similar data recorded for 1 -(3,4-dimethoxypheny1)-2-(2'-methoxyphen0xy)-propane-1,3 diol acetate reported by Ludwig et al (8), and by Hemmer and Liaaen-Jensen for methyl-a-L-rhamnopyranoside triacetate (4).…”

Probing the macromolecular structure of wood and pulps with proton spin-lattice relaxation time measurements in the solid state

“…Progressive reductions of the softening temperatures and the elastic shear moduli were apparent when the total ionic content was increased, while, only marginal increases in the energy dissipation factors (tan 6) were observed. Furthermore, the work of Ludwig et al (1964) documents the presence of extensive interchain hydrogen bonds within lignin. In actual fact, all hydroxyl groups in lignin were found to be hydrogen bonded (Ludwig et al 1964).…”

“…Furthermore, the work of Ludwig et al (1964) documents the presence of extensive interchain hydrogen bonds within lignin. In actual fact, all hydroxyl groups in lignin were found to be hydrogen bonded (Ludwig et al 1964). Since it was suggested by Mark and Atlas (1977) that "the extent of hydrogen bonding in polymers is major factor which determines its softening temperature and elastic modulus", Atack and Heitner (1979) attributed their findings to the elimination of hydrogen bonds from within lignin on progressive sulphonation of wood.…”

Structures of New Dimeric Phenylpropanoids fromMyristica fragransHoutt.

“…327 (1) 222 (4) 221 (9) 207 (2) 196 (3) 195 (18) 194 (100) 193 (9) 192 (3) 179 (7) 167 (9) 165 (12) 163 (9) 390 (2) 372 (I) 329 (l) 224 (5) 223 (8) 209 (1) 208 (I) 197 (10) 196 (100) 195 (8) 194 (5) 181 (2) 180 (I) 168 (I) 167 (45) 165 (10) - (8) 178 (10) 177 (11) 167 (7) 165 (27) 163 (8) 418 (2) 400 (1) 225 (4) 224 (20) 222 (3) 221 (9) 196 (5) 195 (33) 194 (100) 193 (8) 192 (4) 179 (5) 169 (5) 168 (3) 167 (4) 165 (2) 163 (4) 402 (9) 221 (2) 209 (100) 208 (18) 194 …”