Rearrangement of glucose to mannose catalysed by polymer-supported Mo catalysts in the liquid phase

The rearrangement of glucose to mannose was accomplished by ion exchanger resin supported molybdate catalysts in the liquid phase. Sodium molybdate and “molybdic acid” were used as catalyst precursor compounds. The fresh catalysts differ in their content of oligomer Mo species, as could be shown by UV–vis spectroscopy. The catalytic experiments were carried out in batch as well as in continuous mode. The highly selective rearrangement yielded up to 28.4% mannose in the batch and 27.2% in the continous reactor. A “molybdic acid”-based catalyst was tested during a long-term run over 800 h, however deactivation was observed to a certain extent as indicated by decreasing activity. The main cause for deactivation was Mo leaching. A method for the reactivation of used catalysts was elaborated. The initial activity could be received by reloading with fresh molybdate precursor and by reoxidation of reduced Mo species with 1% H2O2.

The rearrangement of glucose to mannose was accomplished by ion exchanger-supported molybdate catalysts. The experiments were carried out in the batch as well as in the continuous mode. A “molybdic acid”-based catalyst was active during an 800 h run. Figure optionsDownload as PowerPoint slide