Similar to FTIR and H NMR C NMR spectrum
Similar to FTIR and 1H NMR, 13C NMR spectrum of liquid product also showed high aliphatic and aromatic carbon content. A typical 13C NMR spectrum of liquid product obtained at 280 °C and 60 min residence time using ethanol as reaction medium Hexa His tag shown in Supplementary Fig. S1. 13C NMR provided greater detail due to their large chemical shift regions and pointed to a high aliphatic content (0–55 ppm). Around 44% of the carbon atoms resonate in the region from 0 to 55 ppm. This region is further sub divided into two regions, region from 0 to 28 ppm which is composed of short aliphatics and region from 28 to 55 ppm comprising of the long and branched aliphatics. The carbon percentage was higher in region from 0 to 28 ppm (31%) than carbon percentage in region from 28 to 55 ppm (13%). The next region of the spectrum, 55–95 ppm indicates the presence of alcohol ethers and carbohydrate sugars. Carbon percentage was very less in this region (1%). The aromatics and the olefinic compounds resonate in downfield region (95–165 ppm). The carbon percentages in this region was very high (54%). 1H NMR also showed high proton percentage in the aromatic region. FTIR and NMR (1H and 13C) indicated that lignin fraction of rice straw was decomposed to low molecular weight monomeric phenols.