Non-Carcinogenic Solvents as Alternative to Benzene for Wood Extractives Determination | ||||
| Alexandria Science Exchange Journal | ||||
| Article 5, Volume 30, JULY- SEPTEMBER - Serial Number 3, September 2009, Page 397-405 PDF (233.77 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/asejaiqjsae.2009.3251 | ||||
 View on SCiNiTO | ||||
| Authors | ||||
| Ramadan A. Nasser; Hamad A. Al-Mefarrej | ||||
| Plant Production Department, College of Food and Agricultural Sciences,King Saud University, P.O. Box 2460 Riyadh 11451, Saudi Arabia | ||||
| Abstract | ||||
| Wood extractives are very important to identify the suitability of wood to different purposes and for wood industries. A solvent mixture of benzene and ethanol is widely recognized as a standard method for removing most wood extractives, in order to determine the chemical composition of wood. Benzene is a carcinogenic substance and exposure to it is one of the most common chemical health risks. Accordingly, benzene as a solvent should be substituted by less hazardous ones. In the current study, six hardwood species were used. Extraction of wood particles was carried out by Soxhlet apparatus in two phases. One of them is a single-phase solvent (benzene, acetone, ether and ethanol), and the other is a combined-phase solvent. In the latter, the specimens were extracted in three steps with benzene-ethanol, ethanol and distilled water according to ASTM method, whereas other specimens were extracted following ASTM method with replacing benzene by either acetone or ether. As a reference basis, the results of combined-phase were compared to NREL method (extracting the specimens with ethanol for 24 hours). The objective of this study was to find a less hazardous solvent replacement to benzene. Results indicate that as comparing to ASTM method, the two alternative methods removed the same amounts of wood extractives for the six wood species studied. Our results indicated that extraction of the six wood species with either acetone-ethanol or ether-ethanol gave closely results that were comparable to benzene-ethanol. Therefore, they can be considered as replacement solvents to benzene-ethanol in ASTM method. Extractives content for all the six wood species achieved by the standard method of NREL were significantly lower than that extracted by either ASTM method or each of the two alternative methods. The method of specimen extraction had a significant effect on lignin and hemicellulose content. The specimens extracted by NREL method had the highest hemicellulose content and the lowest extractive and lignin contents of other methods. | ||||
| Keywords | ||||
| Extractives content; benzene-ethanol; carcinogenic substance; chemical composition of wood; cellulose; lignin; hemicellulose; NREL; ASTM | ||||
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