Carbohydrates oxygen-containing groups

The sugar alcohols or carbohydrate alcohols may be classified as a group of compounds obtained as reduction products of ketoses or aldoses or homologous compounds. Further, they may be considered as compounds of carbon, hydrogen and oxygen, containing typically one hydroxyl group for each carbon atom present in the molecule. Such a... 

Spectra of fulvic acids must be interpreted carefully purification of this fraction leads to losses that can reach 50%. Comparison of spectra of different humic fractions of the same sample, such as a sediment from the Oman Sea (Fig. 6) illustrates several differences. Oxygenated functional groups are more important in fulvic and humic acids than in stable residues. Particularly important are the absorption bands at 3400 cm (OH from alcohols, acids, etc.), 1710 cm (C==0 from quinones, ketones, carboxylic acids), 1250 cm (C—O from alcohols, esters, ethers) and 1050 cm (C—O from carbohydrates). Absorption at 1050 cm is nearly absent in stable residues. Aliphatic content increases from fulvic acids to humic acids and stable residues (bands between 2870 and 2960 cm ) and the shape of the aliphatic bands (2900-2950 1450 1375) indicates that fulvic acids contain mainly CH groups. 

The furanones and pyranones are oxygen-containing heterocyclic compounds associated with both caramelized and Maillard flavors [57]. The odor characters most common to this group of compounds would be caramel-like, sweet, fruity, butterscotch, nutty, or burnt. They predominate both in proportion and absolute amount in condensates of carbohydrates that are subjected to browning reactions [47]. 

The basic carbohydrate molecule possesses an aldehyde or ketone group and a hydroxyl group on every carbon atom except the one involved in the carbonyl group. As a result, carbohydrates are defined as aldehyde or ketone derivatives of polyhydroxy alcohols and their reaction products. A look at the formula for glucose shows that it contains hydrogen and oxygen atoms in the ratio in which they are found in water. The name carbohydrate... 

Phenazines — These are dibenzopyrazine derivatives with fnnctional groups (hydroxy-, carboxy-) at C, and Cg and an oxygen or methyl gronp at Nj and N,o. There are also more complex structures, substituted phenazines, terpenoidal, and carbohydrate-containing phenazines and phenazines derived from saphenic acid. ... 

The hydrothermal carbons obtained in the end from soluble, non-structural carbohydrates are micrometer sized, spherically shaped particle dispersions, containing a sp2 hybridized backbone (also responsible for the brown to black color) decorated with a dense layer of polar oxygenated functionalities still remaining from the original carbohydrate. The presence of these surface groups offers the possibility of further functionalization and makes the materials more hydrophilic and well-dispersible in water. The size of the final particles depends mainly on the carbonization time and precursor concentration inside the autoclave, as well as additives and stabilizers potentially added to the primary reaction recipe. An SEM image of a model reaction illustrating this dispersion state is shown in Fig. 7.1. 

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