Modification of Kraft Lignin with Dodecyl Glycidyl Ether

Acid-Catalyzed Solvolysis of Softwood in Caprylyl Glycol to Produce Lignin Derivatives

Glycol lignin (GL) is produced via the acid-catalyzed solvolysis of softwood meal using glycols such as polyethylene glycol. The physicochemical and thermal properties of GL are expected to be controllable by varying the glycol type. In this study, caprylyl glycol (CG), which is a biobased glycol derived from the caprylic acid component of coconut and palm oils, was used to investigate the effects on the acid-catalyzed solvolysis of softwood. The reactions were performed at 140, 150, and 160 °C for 30-120 min to obtain lignin derivatives (CG-lignin: CGL). The chemical and physical properties of CGLs were investigated. Two-dimensional heteronuclear single-quantum coherence nuclear magnetic resonance analysis suggested that CGL possesses an α-CG-β-O-4 structure as CG is grafted onto the lignin structure. CGLs prepared at higher reaction temperatures exhibited lower molecular weights. The thermomechanical analysis of CGL revealed a glass transition temperature of 89-96 °C and a viscous thermal flow temperature of 134-155 °C.

Methylation of softwood and hardwood kraft lignins with chloromethane

Methylation is a well-established means of enhancing the thermal stability, improving the compatibility in polymer blends, and lowering the glass-transition temperature of lignins. This process normally involves reagents that are costly, associated with poor atom economy and/or highly toxic. Herein, we report the methylation of softwood and hardwood kraft lignins using chloromethane in alkaline aqueous media. This reaction proceeds in high yields at 90-110 °C under moderate pressure (40 psi) while generating environmentally benign sodium chloride and water as by-products.