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Electrodes comprising polypyrrole and alkali lignin are synthesized from acetic acid electrolytes providing high charge-capacity materials based on abundant and renewable biopolymers.

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The effect of temperature on the molecular properties of a "liquid-lignin" phase recovered from Kraft black liquor via CO 2 acidification at elevated temperatures was investigated. For softwood black liquors, up to a 4-fold increase in the molecular weight (mol wt) of the recovered liquid-lignin phase was observed as the acidification temperature was increased from 100 to 150°C. Thus, experiments were carried out in which the CO 2 -acidification steps of preheating, acidification, and phase separation were decoupled from each other in order to elucidate the mechanisms for the observed changes in molecular weight. Results indicate that some lignin cleavage and a corresponding decrease in molecular weight occur during the black-liquor preheating step. However, a significant net increase in molecular weight occurs after the lignin has phase-separated from the black liquor in the form of a new, denser liquid phase, pointing to condensation reactions as the most likely cause. Minimal changes in lignin aromatic content were observed in the new liquid-lignin phase. Because elevated-temperature, CO 2 acidification can be carried out continuously via the SLRP process, adjusting residence times in the black liquor−liquid lignin phase separator would be an effective method for controlling the molecular weight of the recovered lignin for a given product application.

M. Thies).Abstract. The binary phase behavior of supercritical CO 2 with guaiacol, a model lignin monomer that is a liquid at near-ambient conditions,has been determined. A variable-volume, high-pressure view cell was used to observe both liquid-liquid cloud points as well as bubble points along the liquid-liquid-vapor (LLV) three-phase line for this system.CO 2 + guaiacol was found to exhibit Type III phase behavior according to the classification system of Scott and Van Konynenburg, indicating that even at high pressures the mutual solubility of the two components is relatively low. However, the system does exhibit a pressure minimum in the liquid-liquid critical curve at 15 °C and pressures just under 500 bar. The upper critical end point U for the CO 2 -rich liquid phase extends to temperatures and pressures 2.1 °C and 2.2 bar above the critical point of CO 2 .