Glucose liquid-phase

An example for a non-structure-sensitive reaction is provided by Davis et al. [102], who investigated the liquid-phase hydrogenation of glucose over carbon and silica based ruthenium catalysts with particle sizes between 1.1 and 2.4 run. Depending on catalyst loading which was between 0.56 wt.% and 5 wt.%, dispersion decreased from 91% to 43%. At the same time, TOFs varied only insignificantly in a range between 0.21 1/s and 0.32 1/s. 

The Sarex process employs the full allotment of Sorbex beds in addition to the four basic Sorbex zones. When a Sarex unit processes corn syrup that has an approximate composition (on a dry basis) of 42% fructose, 53% glucose and 5% other saccharides, it produces a fructose enriched corn syrup with >95% purity at >90% recovery [34, 35]. The Sarex process employs sufficient operating temperature to overcome diffusion limitations with a corresponding operating pressure to maintain liquid-phase operation. 

An early example of an MIP-QCM sensor was a glucose monitoring system by Malitesta et al. (1999). A glucose imprinted poly(o-phenylenediamine) polymer was electrosynthesized on the sensor surface. This QCM sensor showed selectivity for glucose over other compounds such as ascorbic acid, paracetamol, cysteine, and fructose at physiologically relevant millimolar concentrations. A unique QCM sensor for detection of yeast was reported by Dickert and coworkers (Dickert et al. 2001 Dickert and Hayden 2002). Yeast cells were imprinted in a sol-gel matrix on the surface of the transducer. The MIP-coated sensor was able to measure yeast cell concentrations in situ and in complex media. A QCM sensor coated with a thin permeable MIP film was developed for the determination of L-menthol in the liquid phase (Percival et al. 2001). The MIP-QCM sensor displayed good selectivity and good sensitivity with a detection limit of 200 ppb (Fig. 15.7). The sensor also displayed excellent enantioselectivity and was able to easily differentiate the l- and D-enantiomers of menthol. 

Karkkainen and Vihko,144 in their work cited earlier, also studied the O-trimethylsilyl derivatives of acetamidodeoxyhexoses. Of the two liquid phases that they used, they found QF-1 more suitable for the separation of anomers, but SE-30 was better for separating 2-amino-2-deoxy-D-glucose derivatives from those of2-amino-2-deoxy-D-galactose. 

Gold NPs deposited on carbons are active and selective for mild oxidations in liquid phase although they exhibit almost no catalytic activity in the gas phase. Examples are aerobic oxidation of mono-alcohols, diols, glycerol, glucose, alkenes and alkanes. 

The plerocercoids of this species, which ranged from 2 to 200 mg in the body cavity of the stickleback Gasterosteus aculeatus, have been grown to the infective stage in a relatively simple medium (467). In a liquid phase of 25% (v/v) horse serum, 0.5% (w/v) yeast extract, 0.65% (w/v) glucose in Hanks saline (pH 7.1) and a gas phase of 5% C02 in air, dry weight increases of up to 500% were recorded in 8 days. These worms matured to adults when cultured in vitro at 40 °C. 

Partitioning of carbohydrates in the vapor-liquid-liquid regions of the acetone+water+car-bon dioxide system and the 2-propanol+water+carbon dioxide system has been investigated experimentally between 313 and 343 K and between 4 and 13 MPa. Both series yielded the same qualitative results. Partitioning of the carbohydrates between the two liquid phases of the vapor-liquid-liquid equilibria (VLLE) shows the dependencies of the carbohydrate K-factors on pressure and temperature. The Soave-Redlich-Kwong equation of state is suitable to reproduce carbohydrate partitioning in the glucose+acetone+water+carbon dioxide system. 

Phase compositions of VLLE in the systems glucose + acetone + water + carbon dioxide and carbohydrates + 2-propanol + water + carbon dioxide have been determined experimentally. Like for VLE of related systems from literature, the carbohydrate solubility in a phase rises when the phase becomes more similar to the water-rich lower liquid phase. At the same time separation of different carbohydrates becomes more difficult because selectivity decreases. Theoretically based models can help to find an optimum of capacity and selectivity and to minimize the number of necessary experiments. A simple model based on the Soave-Redlich-Kwong EOS which can reproduce glucose partitioning between the two liquid phases in VLLE in the glucose + acetone + water + carbon dioxide system is presented. 2-Propanol is shown to be a better modifier for these systems than acetone, but denaturation of carbohydrates in the carbohydrate + 2-propanol + water + carbon dioxide system limits industrial applications. 

Recently, some researchers have suggested that ether or ester linkages are hydrolyzed in supercritical water even without any catalyst. Sakaki ct al. have investigated non-catalytic decomposition of cellulose in subcritical water, and cellulose was found to be decomposed to water solubles, which were decomposed further after their yield reached nearly 80%, On entering the second decomposition process, the water solubles were converted into gaseous products and methanol-soluble products, and solid products like char were formed from the liquid phase. The hydrolysate of cellulose obtained in this process was subjected to a fermentation test, and the formed glucose was successfully converted into ethanol. 

Most of these liquid phase catalytic oxidations have been used for the selective oxidation of carbohydrates. In the oxidation of a sugar such as glucose, four basic types of selective oxidation are possible. ... 

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