Abstract: Methods are disclosed for the purification of crude compositions comprising 2,5-furandicarboxylic acid, dimethyl ester (FDME) or other diester derivatives (e.g., dialkyl ester derivatives) of 2,5-furandicarboxylic acid (FDCA), by crystallization. In this regard, certain solvents, and classes of solvents, have been discovered to promote the selective crystallization of FDME over impurities often generated in its production by FDCA esterification and other upstream processing steps. Importantly, certain impurities that are selectively removed include those that would otherwise be detrimental to the color and/or color stability of the purified composition. Other improvements in crystallization reside in the use of techniques such as liquid-liquid extraction and pre-treatment of the crystallization solution by contact with a solid medium.

Abstract: Methods are disclosed for the purification of crude compositions comprising 2,5-furandicarboxylic acid, dimethyl ester (FDME) or other diester derivatives (e.g., dialkyl ester derivatives) of 2,5-furandicarboxylic acid (FDCA), by crystallization. In this regard, certain solvents, and classes of solvents, have been discovered to promote the selective crystallization of FDME over impurities often generated in its production by FDCA esterification and other upstream processing steps. Importantly, certain impurities that are selectively removed include those that would otherwise be detrimental to the color and/or color stability of the purified composition. Other improvements in crystallization reside in the use of techniques such as liquid-liquid extraction and pre-treatment of the crystallization solution by contact with a solid medium.

Abstract: A method for reducing contaminants in the production of a bio-derived glycol product of polyol hydrogenolysis is described. The method involves subjecting an aqueous, polyol product mixture (from the hydrogenolysis conversion of biologically-derived carbohydrate feedstock) to ion-exclusion chromatography to separate and reduce impurities from an eluant fraction containing a desired product, and distilling the eluant fraction to yield the desired product (e.g., propylene glycol or ethylene glycol). The reaction product mixture can be introduced into a continuous ion-exclusion chromatography system to reduce the impurities and produce in a high-throughput manner a finished otherwise commercially acceptable glycol product.

Abstract: A method for reducing contaminants in the production of a bio-derived glycol product of polyol hydro-genolysis is described. The method involves subjecting an aqueous, polyol product mixture (from the hydrogenolysis conversion of biologically-derived carbohydrate feedstock) to ion-exclusion chromatography to separate and reduce impurities from an eluant fraction containing a desired product, and distilling the eluant fraction to yield the desired product (e.g., propylene glycol or ethylene glycol). The reaction product mixture can be introduced into a continuous ion-exclusion chromatography system to reduce the impurities and produce in a high-throughput manner a finished otherwise commercially acceptable glycol product.

Abstract: Processes are described for producing furfural from a mixture of pentoses and hexoses, by dehydrating and cyclizing pentoses to provide furfural using a water-soluble acid at elevated temperatures in the presence of a low-boiling, water-immiscible organic solvent, such as toluene, which is effective for extracting the furfural into an organic phase portion. In certain embodiments, a fermentation step occurs prior to the dehydration step to convert hexoses in the mixed pentoses and hexoses to ethanol while conserving pentoses therein for making furfural.