Carbonyl Groups in Lignin. IV. Infrared Absorption Studies and Examination of the Volumetric Borohydride Method.
- 1 January 1961
- journal article
- research article
- Published by Danish Chemical Society in Acta Chemica Scandinavica
- Vol. 15 (2) , 384-392
- https://doi.org/10.3891/acta.chem.scand.15-0384
Abstract
Infrared absorption studies showed that a mixture of sodium borohydride-reduced Bjorkman lignin with isopropylconiferyl aldehyde (0.033 mole per OCH3 of the mixture), arylpropanone-1 model substances (0.07 mole/OCH3), and arylpropanone-2 models (0.11 mole/OCH3), i.e., a total of 0.21 carbonyl groups per OCH3, gives an absorption pattern in the region of the carbonyl stretching vibration very similar to that given by untreated Bjorkman lignin. Reduction of the latter lignin with sodium borohydride causes the hydroxyl content to increase by 0.20 hydroxyl groups per OCH3. An attempt has been made to explain the discrepancy between the carbonyl values obtained as above as well as by the oximation method (about 0.20 CO/OCH3) and those found by Gierer and Soderberg with a volumetric borohydride method (about 0.40 CO/OCH3). Reexamination of the latter method showed that values which are reasonably close to 0.20 are obtained if air is excluded from the apparatus.This publication has 2 references indexed in Scilit:
- Carbonyl Groups in Lignin. II. Catalytic Hydrogenation of Model Compounds Containing Aryl Carbinol, Aryl Carbinol Ether, Ethylene, and Carbonyl Groups.Acta Chemica Scandinavica, 1961
- Carbonyl Groups in Lignin. III. Mild Catalytic Hydrogenation of Björkman Lignin.Acta Chemica Scandinavica, 1961