Conversion of sugars to ethylene glycol with nickel tungsten carbide in a fed-batch reactor: high productivity and reaction network elucidation

Green Chem., 2013, Advance Article
DOI: 10.1039/C3GC41431K, Paper

Roselinde Ooms, Michiel Dusselier, Jan A. Geboers, Beau Op de Beeck, Rick Verhaeven,
Elena Gobechiya, Johan A. Martens, Andreas Redl, Bert F. Sels
Fed-batch reactor technology was used for the highly productive conversion of
concentrated sugar solutions into ethylene glycol using bifunctional nickel tungsten
carbide catalysts.

Conversion of sugars to ethylene glycol with nickel tungsten carbide

 in a fed-batch reactor: high productivity and reaction 

network elucidation

 

 http://pubs.rsc.org/en/Content/ArticleLanding/2013/GC/C3GC41431K?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

 

 

 Bifunctional nickel tungsten carbide catalysis was used for the conversion of aqueous sugar

 solutions into short-chain polyols such as ethylene glycol. It is shown that very concentrated sugar 

solutions, viz. up to 0.2 kg L⁻¹, can be converted without loss of ethylene glycol selectivity 

by gradually feeding the sugar solution. Detailed investigation of the reaction network

 shows that, under the applied reaction conditions, glucose is converted via a retro-aldol

 reaction into glycol aldehyde, which is further transformed into ethylene glycol by hydrogenation. 

The main byproducts are sorbitol, erythritol, glycerol and 1,2-propanediol. 

They are formed through a series of unwanted side reactions including 

hydrogenation, isomerisation, hydrogenolysis and dehydration. 

Hydrogenolysis of sorbitol is only a minor source of ethylene glycol. To assess the 

relevance of the fed-batch system in biomass conversions, both the influence of the

 catalyst composition and the reactor setup parameters like temperature, pressure 

and glucose addition rate were optimized, culminating in ethylene glycol yields up to 66% and

 separately, volume productivities of nearly 300 g_EG L⁻¹ h⁻¹.