Issue 5/2018 - Progress on the green synthesis route of paraxylene

Recently, Li Changzhi, associate researcher of the Dalian Institute of Chemistry, Chinese Academy of Sciences, and others have made new progress in the synthesis route of green paraxylene (PX), and designed a synthesis route
using tungsten carbide to catalyze the intramolecular hydrogen transfer tandem reaction using lignocellulosic resources biological fermentation product (bio-based isoprene) and glycerol dehydration product (acrolein) as raw materials.
The reaction achieves a total PX yield of up to 90%, the results of which were published in
the German Journal of Applied Chemistry.

Catalyzed by Lewis acid ionic liquid, the researchers constructed a six-membered ring intermediate with para-substituents through the Diels-Alder reaction
.
Subsequently, the intermediate is formed by
continuous gas-phase dehydrogenation-hydrodeoxygenation reaction under the action of tungsten carbide catalyst.
The research team used tungsten carbide as a catalyst to achieve a highly coupled reaction
of dehydroaromatization and hydrodeoxygenation through intramolecular hydrogen transfer.
The surface shear reaction mechanism of tungsten carbide in this process is completely different from the traditional noble metal catalytic process, and the carbon atoms can be retained 100% in the product, which is convenient for the separation
of PX products.
The research results provide a new idea
for exploring the preparation of aromatic chemicals from biomass resources.