Characterization of liquefied products from model woody components in the presence of mineral acid catalysts

Abstract

Cellulose and lignin are the main structural polymers in the plant cell wall. Cellulose is the structural component of the primary cell wall of green plants, many forms of algae and the oomycetes. About 40-50% of woody matter is cellulose. Lignin is a highly cross-linked polymer created by the polymerization of substituted phenolic compounds, known as monolignols, such as coniferyl, pcoumaryl, and synapyl alcohol. Liquefaction process is one of the promising techniques for effective utilization of woody biomass for the lignocelluloses can be converted to liquid reactive materials as the bio-based materials. Cellulose would have an advantage of providing liquefied product with small range of variance. The phenolated woody components have high acidity in the presence of mineral acid catalysts and possess the constituents which can react with formaldehyde. In addition, lignin, one of the major woody components including the hydroxyl-benzyl structure, has the potential to react with formaldehyde. However, as its complexity in structure, the liquefaction mechanism and the liquefied products with phenol should be found out to solve some problems such as the reaction efficiency and low molecular weight products, and it will be useful to preparation of bio-based materials thought the liquefaction processes. In our study, two model woody components have been used under the different liquefaction conditions with phenol. In our experiments, the model cellulose component is specially used in the experiment to test the characteristics of the products under different ratios. As the results, we found that the final liquefied products from model component substance of lignin only 17.2% (wt) and the growth rate is very low with the molecular weight (Mw) up to 2119 under the reaction temperature of 150°C and 3 hours in the liquefaction experiments. However, the model cellulose component was confirmed to contribute more. On the contrary, the Mw of raw woody powder material can be reach to 1851. In a series of the mixing experiments, we found that the variation of Mw in the different experimental conditions determined by a gel permeation chromatography. From the results of liquefaction residue, we calculated the activation energy, and compared the value of those in different conditions. The solubility of the phenolated woody powder had been evaluated in eight organic solvents to evaluate the hydrogen bonding strengths of these solvents. It is very helpful for sustainable chemistry if polymeric materials can be effectively produced from the biomass liquefaction processes.