The solubility and softening behavior of lignin from acid-catalyzed ethanol/water pulping was determined in various ethanol/water solvent mixtures and a process relevant temperature range. The operation conditions for an optimized lignin separation process have been derived from the determined lignin phase behavior. The continuous lignin separation and solvent recovery process (LigniSep) has been developed in lab scale and up-scaled to a dedicated pilot plant at Fraunhofer CBP (Leuna, Germany). Agglomeration of softened lignin particles and lignin “stickiness” were adjusted by temperature (38-44 °C at 80-120 mbar) and ethanol content of the lignin dispersion (6-9 wt.%), which was monitored by inline infrared spectroscopy. Ethanol recovery by evaporation and lignin particle formation were facilitated simultaneously. The agglomeration behavior of different lignins was monitored via inline particle size analysis. Optimal process conditions resulted in good filterability of the lignin dispersion with average filter cake resistances of 10^11 to 10^13 m^-2 and lignin yields near 100 wt.% of water-insoluble lignin.

Crystallization-based separation of curcumin from ternary mixtures of curcuminoids having compositions comparable to commercial extracts was studied experimentally. Based on solubility and supersolubility data of both, pure curcumin and curcumin in presence of the two major impurities demethoxycurcumin (DMC) and bis(demethoxy)curcumin (BDMC), seeded cooling crystallization procedures were derived using acetone, acetonitrile and 50/50 (wt/wt) mixtures of acetone/2-propanol and acetone/acetonitrile as solvents. Starting from initial curcumin contents of 67–75% in the curcuminoid mixtures single step crystallization processes provided crystalline curcumin free of BDMC at residual DMC contents of 0.6–9.9%. Curcumin at highest purity of 99.4% was obtained from a 50/50 (wt/wt) acetone/2-propanol solution in a single crystallization step. It is demonstrated that the total product yield can be significantly enhanced via addition of water, 2-propanol and acetonitrile as anti-solvents at the end of a cooling crystallization process.