Hydrogenation glucose

Gallezot, P., Nicolaus, N., Fleche, G., Fuertes, P., and Perrard, A. (1998) Glucose hydrogenation on ruthenium catalysts in a trickle-bed reactor. J. 

P. Gallezot, P.J. Cerino, B. Blanc, G. Fleche and P. Fuertes, Glucose Hydrogenation on Promoted Raney-Nickel Catalysts, Journal of Catalysis 146 (1994) 93. 

P. Gallezot, N. Nicolaus, G. Fleche, P. Fuertes and A. Perrard, Glucose Hydrogenation on Ruthenium Catalysts in a Trickle-Bed Reactor, Journal of Catalysis 180 (1998) 51. 

N. Dechamp, A. Gamez, A. Perrard and P. Gallezot, Kinetics of glucose hydrogenation in a trickle-bed reactor. Catalysis Today 24 (1995) 29. 

Glucose hydrogenation to sorbitol was carried out on 40 wt% aqueous solution at 100°C, under 80 bar H2-pressure, in the presence of Ru/ACC catalysts prepared by cationic exchange and anionic impregnation. The hydrogenation of 10 wt% aqueous glucosone solution was conducted at 80°C under 80 bar H2-pressure on 2.5 wt%Pd/ACC catalyst in the presence of small amounts of NaHC03 added to increase the pH of reaction medium. Reaction kinetics was followed by HPLC and GC analysis of the reaction medium at different time intervals. 

Furthermore, similar glucose hydrogen breath tests in the elderly with and without omeprazole [76] and normal 14C-r/-xylose breath test in healthy old people with acquired gastric hypochlorhydria (pH >6) [32] counterindi-cate that H2 blockers induce colonization with strict anaerobes of intestinal types (colonic flora) in the upper gut. 

Hutchinson S, Fogan R The effect of long-term omeprazole on the glucose-hydrogen breath test in elderly patients. Age Ageing 1997 26 87-89. 

Glucose oxidase 1.1.3.4 Glucose Hydrogen peroxide Oxidation of a chromogen... 

Tukas, V. Glucose Hydrogenation in a Trickle-Bed Reactor. Collect. Czech Chem. Commun. 1997, 62, 1423 - 1428. 

Unlike most studies performed on one single reactor type, Turek et al [43] compared 4 reactors STR, TBR, spinning basket reactor, piston recycling reactor, with different nickel on silica particle sizes (glucose hydrogenation). See also [44]. 

ACTIVITY AND STABILITY OF PROMOTED RANEY-NICKEL CATALYSTS IN GLUCOSE HYDROGENATION... 

It is well known, even from old literature data (ref. 1) that the presence of metal promotors like molybdenum and chromium in Raney-nickel catalysts increases their activity in hydrogenation reactions. Recently Court et al (ref. 2) reported that Mo, Or and Fe-promoted Raney-nickel catalysts are more active for glucose hydrogenation than unpromoted catalysts. However the effects of metal promotors on the catalytic activity after repeated recycling of the catalyst have not been studied so far. Indeed, catalysts used in industrial operation are recycled many times, stability is then an essential criterion for their selection. From a more fundamental standpoint, the various causes of Raney-nickel deactivation have not been established. This work was intended to address two essential questions pertinent to the stability of Raney-nickel in glucose hydrogenation namely what are the respective activity losses experienced by unpromoted or by molybdenum, chromium and iron-promoted catalysts after recycling and what are the causes for their deactivation ... 

We first became interested in this area from studying volatiles produced in model Maillard systems. Shibamoto and Russell ( 1, 2) studied model systems such as glucose/hydrogen sulfide/ammonia and reported volatile profiles which contained many of the... 

Additional tests with ammonium compounds were performed to address the effect of ammonium ion (see Fig. 8). It is clear that the catalyst inhibition was not based only on the presence of ammonium ion. Ammonium carbonate showed the largest inhibition of the glucose hydrogenation reaction, while chloride and hydroxide had lesser effects. Ammonium nitrate caused no apparent inhibition on glucose conversion. A similar lack of effect was shown with potassium nitrate. In the case of ammonium nitrate, the glucose conversion mechanism was affected, so that the sorbitol yield was reduced by about 20%, but numerous byproducts and overreaction products (lower molecular weight polyols) were evident. 

Castoldi, M., Camara, T., Monteiro, R.S., Constantino, A.M., Camacho, L., Carneiro, M. and Aranda, G. 2007. Experimental and Theoretical Studies on Glucose Hydrogenation to Produce Sorbitol. React. Kinet. Catal. L, 91, 341-352. 

TABLE 48-6 Reported Sensitivity and Specificity of Lactulose and Glucose Hydrogen Breath Tests for the Diagnosis of Bacterial Overgrowth... 

Watts D, Brydon G, Crichton S, Ghosh S, Glucose hydrogen breath test in the investigation of diarrhoea. Gut 2000 46(suppl I1) A23. 

Pizzariello, A., Stredansky. M.. and Miertus, S. (2002) A glucose/hydrogen peroxide biofuel cell that uses oxidase and peroxidase as catalysts by composite bulk-modified bioelectrodes based on a solid binding matrix. Bioelectrochemistry, 56 (1-2), 99-105. 

The rate of glucose hydrogenation was determined in the trickle phase with a 120-ml tubular reactor using 20 ml of either 4-mm activated tablets or hollow spheres. This hydrogenation was performed at 50 bar hydrogen pressure, 140°C, and at LHSV of 3.0 h with a 40% aqueous glucose solution. Glucose conversion and selectivities were determined by HPLC. 

Figure 6 compares the glucose hydrogenation activity of the activated Metalyst tablets to those of the various activated Metalyst hollow spheres. In this... 

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