Concentration Of Carboxylic Acid Groups Research Articles

Oxidative weathering of Illinois No.6 coal

The exposure of freshly-mined Illinois No.6 bituminous coal (Monterey Mine No.1) to atmospheric oxygen at ambient conditions resulted in a slow oxidation reaction which appeared to be complete within two months to produce an oxidized coal product with ≈26% more organically bound oxygen than the fresh coal. An oxygen functional group analysis was performed to determine the carboxylic acid, hydroxyl and ether group content of the coal before, during and after the reaction. Infrared analysis showed no carbonyl production; however, ether functionality was being produced. O-methylation reactions which employed isotopically labelled methyl groups (both C-13 and deuterium) were used to identify and quantify O-H and CO 2H sites in the weathering coal samples. It was found that these acidic groups were not the products of oxidative weathering. Essentially all of the chemically incorporated oxygen eventually formed ether linkages. In a related study on this coal, hydroperoxide was detected as a transient intermediate in the early stages of the oxidation. A mechanism is proposed which involves the simultaneous formation under mild temperatures of a hydroperoxide and a carbon radical that undergoes a radical displacement producing the ether product directly. Solvent swelling studies revealed that these ethers act as cross-linking agents in the coal structure. The more highly cross-linked coal structure that resulted from weathering was responsible for the destruction of the plastic properties of this bituminous coal.

Infrared study of the pyrolysis products of sporopollenin and lignite

The effect of pyrolysis at increasing temperature on sporopollenin, lignite and sporopollenin oxidized at 200°C has been investigated using measured infrared band absorption coefficients. Oxidation of sporopollenin in air at 200°C is marked by a decrease in the content of saturated hydrocarbon chains and a strong increase in the concentration of carboxylic acid groups. Pyrolysis of a thick bed of sporopollenin at increasing temperatures leads to the removal of a large proportion of oxygenated functions, before the removal of hydrocarbons. For lignite and oxidized sporopollenin, the loss of both types of functional groups extends over a broader temperature range. Reorganization of the carbonaceous residue at high temperature is hindered if a sufficiently low content of oxygenated functions, carbonyl and carboxyl as well as hydroxyl and ether groups, is not reached before the elimination of hydrocarbons.

CHEMICAL AND INFRARED SPECTROSCOPIC STUDIES OF FULVIC ACID FRACTIONS FROM A PODZOL

SummaryInfrared spectroscopy and chemical degradation indicated several fulvic acid fractions from an iron‐humus podzol capable of complexing and translocating metals. Acidic polysaccharides, some of them resembling pectic acid, were isolated in appreciable quantities. These are able to bind metals through carboxyl groups, but peptide components present in the polysaccharide fraction may provide alternative metal complexing centres. The high yield of acid‐extractable organic matter from the illuvial humus, together with its high content of carboxylic acid groups, make it likely that this fraction plays a major role in the translocation of metals. Phenolic compounds allegedly associated with this process were present in the fulvic acid solution in low amounts, and only in the extracts from the organic horizons.

The Reactions of Cellulose with Amic Acids and Anhydride/Aminonia

Formulas have been developed for the calculation of free, total, and crosslink degree of substitution in Cellulose Ester Derivatives. Free and total carboxylic acid group content from established analytical methods is required.

Influence of Soil Exchangeable Cation Ratios on the Aggregating Effects of Natural and Synthetic Soil Conditioners

The aggregating effects of various natural and synthetic soil conditioners in normal soils and in soils varying widely in exchangeable cation percentages have been investigated. In the normal soils VAMA (a copolymer of vinyl acetate and the partial methyl ester of maleic acid), two dextrans from soil bacteria, IBMA (a copolymer of isobutylene and the half ammonium-half amide salt of maleic acid), fructosan from Bacillus subtilis, and mesquite gum exerted the greatest initial aggregating effect; carboxymethylcellulose and pectin exerted an intermediate effect; and ammonium alginate and arabogalactan (larchwood gum) exerted little or no binding action. Ammonium lignin sulfonate had a small initial effect which increased with time; it thus indicated dependence upon microbial activity. The various soil exchangeable cation ratios greatly affected the aggregating action of some of the soil conditioners but had little influence on others. The binding action of VAMA was slightly reduced by 60% Na only, while that of IBMA (tested in Yolo loam soil only) was reduced by 10 to 60% Na and 30 to 60% K. The aggregating effect of polysaccharide type conditioners appeared to be directly related to the concentration of carboxylic acid groups in these materials. As the concentration of uronic acid groups increased, the binding action of the materials increased with increasing exchangeable H and decreased with increasing exchangeable Na or K. Possible explanations for this behavior are discussed. The effectiveness of VAMA did not decrease with time up to 200 days. In the high Na, K, and Mg soils the effectiveness of IBMA decreased with time. The binding action of all the other materials used gradually decreased, but they were more stable in the acid soils than in the neutral to alkaline soils.