Jakob Burger

Recovery of furfural and acetic acid from wood hydrolysates in biotechnological downstream processing

Abstract Wood hydrolysates contain sugars that can be used as feedstock in fermentation processes. For that purpose, the hydrolysate must be concentrated and inhibitors that harm fermentation must be removed. Herein, the integration of these tasks with the recovery of inhibitors is studied. The wood hydrolysate is represented as a mixture of water, xylose, acetic acid, and furfural. Acetic acid and furfural are two frequently occurring inhibitors and valuable chemicals, and thus, their recovery is studied. Furfural is recovered from the vapors by heteroazeotropic distillation. It is shown that this can be achieved without additional energy. The recovery of acetic acid by distillation is also possible, but not attractive. The new process is simulated by using a thermodynamic model based on experimental data.

Solid-Liquid Equilibrium in the System 2-Keto-L-Gulonic Acid + L-Ascorbic Acid + Water

Abstract The solid‐liquid equilibrium (SLE) in the ternary system 2‐keto‐L‐gulonic acid (HKGA) + L‐ascorbic acid (vitaminu2009C) + water was investigated experimentally at temperatures between 276u2009K and 308u2009K at ambient pressure, i.e., under conditions that are of particular interest for industrial applications. Phase diagrams with one eutonic point were obtained for all temperatures. The dissociation constant and the solubility constant of vitamin C were determined as a function of temperature. Based on an extended version of the Debye‐Hückel theory, a physicochemical model was developed that describes the SLE in the ternary system. The agreement between experimental data and results from the model is excellent.