Properties And Application Of Poplar Organic Volatiles During Thermal Treatment

In order to volatile organic compounds(VOCs) emitted from wood in heat-treated process and further using process, and the chemical constitution of condensate from heat-treated process and its further utilization, poplar wood samples were heat treated at different temperatures(160℃,180℃,200℃ and 220℃), the chemical constitution of VOCs emitted from different treated processes and those residual in treated wood has investigated by GC-MS, chemical constitution of heat-treated wood samples was calculated by wet chemistry methods, chemical constitution of condensate from different treating processes was also analyzed. All condensates were irrigated the seeds after purification. And results are showed as below:After heat-treatment, the surface color of treated wood samples was darken, and the color was darker as the treating temperature increasing, when treated at temperatures exceeding 200℃, the surface texture was more obvious.The near infrared spectrum showed that:hemicellulose degraded firstly during heat treatment, and was degraded massively, furfural was formatted during the degradation of hemicellulose, and amorphous regions of cellulose were also degraded during heat treatment, as a result, large numbers of extractives were produced. Crystalline regions of cellulose and lignin barely degraded during heat treatment, they just degraded when treated at high temperatures. Results of wet chemistry methods were accordant with near infrared spectrum.The results of GC-MS analysis upon untreated and heat-treated wood samples show that:large amount of carboxylic acids were existed in untreated wood samples, and then disappeared during the following heat-treatments. As the degradation of hemicellulose during heat-treatment, the content of aldehydes, especially furfural, increased rapidly, and reached the max value when treated at the temperature of 180℃, and then decreased. Aromatic compounds and esters are also produced during heat-treatments, and were the main VOCs emitted from wood samples treated at high temperatures.Numerous of compounds were produced during heat-treatments of poplar wood, changes in species of volatile organic compounds between wood samples treated at different temperatures were not obvious, alkane, aldehydes, terpene were existed in all wood samples, but the changes were obvious between different treating processes, alkane was produced in early stages of heat-treatment, and terpene was produced in heat preservation process.Condensates from different treatment all contained large numbers of chemical compositions, condensates from wood samples those treated at high temperatures contained lots of nitrogenous compounds, it can promote the sprouting of seeds, dilute condensates from wood samples treated at high temperatures has the most obvious efficiency.