Na2CO3 Catalytic Decomposition of Wheat Straw in Supercritical Methanol

Catalytic methanolysis of wheat straw (WS) pretreated by Na2CO3 with different concentrations was performed at 270 and 300 degrees C, respectively. The samples without pretreatment and with pretreatment by 0.1 and 0.5 mol/L Na2CO3 were denoted as WS0, WS0.1 and WS0.5, respectively. The results show that the maximum and minimum yields of bio-oil were obtained from catalytic methanolysis of WS0.1 and WS0.5, respectively. In addition, the yield of bio-oil and the conversion at 300 degrees C were both higher than that at 270 degrees C. Compounds identified with gas chromatograph/mass spectrometer (GC/MS) in bio-oil were classified into alcohols, alkanes, esters, furans, cyclopentanones, phenols, aldehydes, benzenes, ketones, nitrogen-containing compounds and other compounds. FTIR analysis of bio-oil shows that most of soluble organic compounds are oxygen-containing species and phenols are the most abundant in bio-oil. The relative content (about 10%) of phenols in bio-oil of WS0.1 and WS0.5 were lower than that in WS0, while the relative content of furans and esters increases about 10%. These facts indicate that a certain dose of Na2CO3 was able to promote the methanolysis of cellulose and facilitate a further decomposition of lignin.