D-glucose solution

After the autoclaving (100°) of D-glucose solutions, both 5-(hydroxy-methyl)-2-furoic acid and 2,5-furandicarboxylic acid were detected. No attempt was made to remove oxygen from the starting solutions. Although the D-glucose solution was not initially acidic, subsequent experience indicated that the final pH was probably 4. Air exposure (mild oxidation) of the mixtures increased the two furancarboxylic acids at the expense of 11. 

As the conductivity of the equilibrium mixture in 0.5 M boric acid amounts to about 65 units, the quantities of D-galactofuranoses are smaller than for D-glucose solutions, but on the other hand the mutarota-tion proceeds somewhat more rapidly. It may also be observed that in pure water both isomers also show a gradual increase in conductivity, which however is much less than in 0.5 M boric acid. 

Spectra of various aqueous solutions, including 1.8 M D-glucose solution were measured171 with a Fourier-transform, infrared spectrometer. The data obtained for dilute solutions were found useful for the usual qualitative purposes, and also amenable to quantitative analysis, but the spectra of such concentrated solutions as 1.8 M D-glucose show distortions of the background at >3000 cm-1, and negative, water deformation bands. These distortions were attributed to structural changes of water in the presence of the solutes. 

Effect of Individual Amino Acids and pH on the Color Developed in a 0.025 M d-Glucose Solution Heated for 20 Minutes at 114° in an Autoclave163... 

Fig. 7.—The Effect of Different Amino Acids on the Loss of Amino Nitrogen of a 50% D-Glucose Solution Containing the Amino Acid, at pH 5.25 and Reflux Temperature for 10 Hours. (The effect of different amino acid concentrations on the loss of amino nitrogen is also shown.17 )...

Effect of Various Amino Acids on the Color Developed in a Dilute d-Glucose Solution atm pH 8... 

The rate of the isomerization reaction, catalyzed by a given quantity of D-glucose isomerase in the fixed form, suspended in a given volume of D-glucose solution in cases studied, is about the same as when the same quantity of D-glucose isomerase in the soluble form is dissolved in that volume of the solution of D-glucose. 

The course of the isomerization reaction observed in a suspension of the fixed isomerase in D-glucose solution is translatable to the degree of isomerization attainable as a function of the rate of flow of the substrate through a bed of the fixed isomerase. In adapting the rate expressions 4 and 6 to a reactor in which substrate flows continuously through a bed of fixed enzyme, the factor t expresses the ratio of the volume of substrate in contact with enzyme in the reactor to the volumetric rate of flow. 

When maximum concentration of enzyme is attained in the fermenter, the broth may be filtered, the solid washed thoroughly with water, and the enzyme-containing cell-mass used directly in isomerization reactions. Takasaki and Kamibayashi described a heat-treatment system that was applied to a Streptomyces fermentation-broth before filtration, and that fixed the isomerase within the cell structures by inactivating lytic enzymes that would otherwise cause the isomerase enzyme to be leached out of the cell when added to substrate in the isomerization reactors.44 The cell-fixed isomerase can be used in stirred-tank or fixed-bed reactors through which the D-glucose solution to be isomerized may be passed continuously while the enzyme that is fixed within the cell material is retained in the reactor. 

Depolarized Raman spectra below 250 cm" in liquid water (H2O, D2O and H2 0), aqueous electrolyte solutions (LiCl, NaCl, KCl, RbCl, MgCl2 and CaCl2), D-glucose solution and ascOTbic acid isomerism solutions (L-xylo and D-arabo) were investigated. The Raman spectra... 

Fig.5 Concentration dependence of the characteristic frequencies of D-glucose solutions.

Durham DG, Hung CT, Taylor RB. Identification of some acids produced during autoclaving of D-glucose solutions using HPLC. Int J Pharm 1982 12 31 0. 

In solutions under vacuum, absorption maximum at 265 nm is shown after treatment with ionizing radiations, but no explanation was apparent until the work of Phillips and coworkers, who proved that 1,3-dihydroxy-2-propanone must be responsible for this absorption. Indeed, irradiated D-glucose solutions display this same absorption, and the formation of... 

Learning Goal 0 Draw the structure for D-glucose. Solution Glucose is an aldohexose. ... 

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