Industrial & Engineering Chemistry Research, Vol.39, No.8, 3112-3115, 2000
A rapid method for determining the extractives content of wood pulp
Accelerated solvent extraction (ASE) with acetone is used to extract thermomechanical wood pulp (TMP). The quantity of extracts obtained through ASE is compared with that acquired using acetone in the standard Soxhlet procedure of the Canadian Pulp and Paper Association (CPPA test method G20). The content, by weight, of acetone-soluble extractives in the TMP is 2.00 +/- 0.05% as determined using ASE and 1.81 +/- 0.02% as determined by Soxhlet extraction. The relative standard deviation of the ASE determination (2.6%) is slightly larger than that of the Soxhlet determination (1.1%) because of the smaller sample size used in ASE. Analysis of the extracts indicates that ASE and Soxhlet extraction acquire similar amounts of the fatty acids, resin acids, and sterols present in the TMP. In addition, ASE extracted a greater amount of lignin from the TMP than did the Soxhlet procedure. In terms of the overall efficiency, ASE was 30 times faster and used 75% less solvent than Soxhlet extraction.