Hydrogenation of D-glucose

The catalytic hydrogenation of D-glucose to D-sorbitol is carried out at elevated temperature and pressure with hydrogen ia the preseace of nickel catalysts, in both batch and continuous operations, with >97% yield (56,57). The cathodic reduction of D-glucose to L-sorbitol has been practiced (58). D-Mannitol is a by-product (59). 

Hydrogenation reactions, particularly for the manufacture of fine chemicals, prevail in the research of three-phase processes. Examples are hydrogenation of citral (selectivity > 80% [86-88]) and 2-butyne-l,4-diol (conversion > 80% and selectivity > 97% [89]). Eor Pt/ACE the yield to n-sorbitol in hydrogenation of D-glucose exceeded 99.5% [90]. Water denitrification via hydrogenation of nitrites and nitrates was extensively studied using fiber-based catalysts [91-95]. An attempt to use fiber-structured catalysts for wet air oxidation of organics (4-nitrophenol as a model compound) in water was successful. TOC removal up to 90% was achieved [96]. 

B.W. Hoffer, E. Crezee, P.R.M. Mooijman, A.D. van Langeveld, F. Kapteijn and J.A. Mouhjn, Carbon supported Ru catalysts as promising alternative for Raney-type Ni in the selective hydrogenation of D-glucose, Catalysis Today 79-80 (2003) 35. 

The first recorded reduction of D-glucose to sorbitol was in 1890 by Meunier who used sodium amalgam. Ipatieff reported the first catalytic hydrogenation of D-glucose to sorbitol. Since then there have been... 

The semi-synthetic production of vitamin C is rapidly moving to a full biotech process. Vitamin C (ascorbic acid) is an important segment in the worldwide vitamin market with a market share of approximately 20 percent. Its worldwide sales amounted to around USD 0.5 bilHon in 1999. The traditional route to vitamin C is a multistep process involving chemical and fermentative steps. It starts with the catalytic hydrogenation of D-glucose to D-sorbitol, followed by the fermentative oxidation of D-sorbitol to L-sorbose, which is then converted... 

Some details are given by Merck in Ref. 112. The electrochemical oxidation is performed in alkaline solution using nickel or nickel oxide electrodes [113]. Hydrogen evolved at the cathode can be used for the hydrogenation of D-glucose to D-sorbitol, the first step in the vitamin C synthesis by the Reichstein route. Obviously, Merck doesn t use electrodes with high specific areas but prefers to stop the electrolysis at a conversion rate of 90%. The oxidation is completed with sodium hypochlorite solution. 

By the hydrogenation of D-glucose, a hexafunctional polyol, sorbitol is obtained, one of the most important starters to initiate the polymerisation of propylene oxide (PO) to hexafunctional rigid polyether polyols. 

An efficient single-step catalytic process was recently developed for the conversion of glucan-type polysaccharides, especially starch, to sorbitol [15]. This process is characterized by the simultaneous hydrolysis of the polysaccharide and hydrogenation of the liberated monosaccharide. The catalyst used is Ru-loaded H-USY zeolite (3 % wlw Ru) in which the zeolitic material fulfils the role of metal carrier (Ru) and solid-acid catalyst. The zeolite provides the Brpnsted acidity required for the hydrolysis reaction either because of its outer surface or by introducing some homogeneous acidity, and the Ru catalyzes the hydrogenation of D-glucose to sorbitol (Scheme 2). 

Selective Hydrogenation of D-Glucose Over Monolithic Ruthenium Catalysts... 

In this study, the influence of dispersion and distribution of the active phase (rnthenium) and the accessibility and performance of the carbon-based monolithic strnctures have been evaluated in the hydrogenation of D-glucose. Special attention has been paid to the stabihty of the catalysts in successive hydrogenation rnns. Especially, fixed-bed catalysts (e.g., monoliths) require a maintained activity for long periods of time for successful application in industry. The performance of the monolithic reactor has been compared with slurry-phase operation. 

Two new methods for the reduction of aldonolactones to aldoses have been developed for use in small-scale syntheses either the lactone itself was reduced with diborane in THF, or an 0-tetrahydropyranyl derivative was reduced with a 1 1 mixture of lithium aluminium hydride and aluminium chloride in ether. The yield of aldose depends on a number of factors and may be low due to the ease of reduction of the aldose to the alditol. The catalytic hydrogenation of D-glucose in the temperature range 100—170 °C and at pressures of 20—80 atmospheres has been examined the effects of pH and promoters (e.g. magnesium, barium chloride, calcium sulphate) were also examined. The rate of hydrogenation was enhanced at pH 8, and calcium sulphate was the most effective promoter at pH 6.8. 

Kolaric, S. Sunjic, V. (1996) Comparative-study of homogeneous hydrogenation of D-glucose and D-mannose catalyzed by water-soluble Ru(tri(m-sulfophenyl)phosphine) complex, J. Mol Catal A-Chem, 110,189-93. 

Compared to the classical two-step fermentation process, the new two-step fermentation process-based one-step process could further ehminate the cost of hydrogenation of D-glucose to D-sorbitol. Based on the two-step fermentation process, Anderson et al. expressed a 2,5-DKG reductase from Corynebacterium ATCC 31090 in E. herbicola ATCC 21988. The recombinant E. herbicola strain could accumulate 1 g 1 of 2-KLG from saturated D-glucose solution [31]. Using protoplast fusion of an E. herbicola and a Corynebacterium strain, the resulting strain could produce 2.07 gl of 2-KLG [40]. According to the limited literature in the public domain, the new two-step fermentation process-based one-step process seems to be less efficient than the classical two-step-based process. 

Crezee E, Hoffer BW, Berger RJ, Makkee M, Kapteijn F, Moulijn JA. Three-phase hydrogenation of D-glucose over a carbon supported ruthenium catalyst—mass transfer and kinetics. Appl Catal A 2003 251 1-17. 

Hiraoka S, YamazaM T, Kitazume T. Stereoselective hydrogenation of D-glucose-derived endo-olefins with a CF3 group. Experimental and theoretical explanations. LLetero-cycles 1998 47 129-132. 

---