Mellitic acid

See also Mellitic acid.) [PHTHALIC ACID AND OTHERBENZENEPOLYCARBOXYLIC ACIDS] (Vol 18)... 

Neither benzenepentacarboxylic acid nor mellitic acid are manufactured commercially, but synthetic mellitic acid can be purchased as a laboratory chemical (99). Both can be synthesized by oxidizing the corresponding methylbenzenes or other substituted benzenes, and both are present in trace amounts after oxidation of coal or coal-like substances. 

The composition varies with the heat treatment and the end point according to x-ray diffraction studies it is a form of carbon that reconverts to weU-ordered graphite on heating to 1800°C. Before the use of x-rays, chemists used the Brodie reaction to differentiate between graphitic carbons and turbostratic carbons. Turbostratic carbons yield a brown solution of humic acids, whereas further oxidation of graphite oxide produces mellitic acid (benzenehexacarboxyhc acid) [517-60-2] ... 

Honig-harnruhr, f. diabetes mellitus. -klee, m. sweet clover, melilot. -saft, m. nectar, -silure, /. Pharm.) oxymel mellitic acid, -acheibe, /. honeycomb, -aeim, m. liquid honey. -stein, m. honeystone, mellite. -steinsilure, /. mellitic acid, honigsliss, a. honey-sweet. 

Copper(II) oxide and cobalt(II) hydroxide form cements with solutions of many multifunctional organic acids propanetricarboxylic acid, tartaric acid, malic acid, pyruvic acid, mellitic acid, gallic acid, tannic acid and phytic acid (Allen et al., 1984 Prosser et al., 1986). These have been used mainly in cement devices for the sustained release of copper and cobalt (Manston et al., 1985 Mansion Gleed, 1985). Little is known about... 

Oxidation of the durene derivative to benzenehexacarboxylic acid (mellitic acid) in an autoclave is normally effected in stages, initially by heating at 80-104°C with the vent open to allow escape of the evolved gases. Subsequent heating to a higher temperature with the vent closed completes the reaction. On one occasion omission of the first vented heating phase led to explosive rupture of the autoclave at 80° C. 

Mellitic acid can be decarboxylated to yield pyromellitic acid, either by the action of heat alone 4 or in the presence of sulfuric acid.5... 

The oxidation of wood charcoal by means of sulfuric acid leads to mellitic acid and its decarboxylation products 6 nitric add may also be employed.7 Pyromellitic acid has also been obtained by the electrolytic oxidation of graphite in an alkaline medium.8... 

The most common plasticisers for PVC are phthalate esters prepared from aliphatic C8 alcohols. For high temperature applications higher molecular weight esters are used, e.g., from mellitic acid, which are resistant to volatilisation and are used for PVC interiors in cars (to prevent fogging of windscreens). 

Malonic acid diamide, m4 Malonylurea, bl Margaryl alcohol, hi a Mellitic acid, b20 MEM chloride, m74 Menadione, m321 1,8-Mentanediamine, d51 / -Mentha-1,8-diene, L17, L18 / -Mentha-6,8-dien-2-one, c20 Mercaptobenzene, tl 56... 

If the oxidation of graphite by nitric acid is conducted in the presence of catalysts, such as vanadic acid or silver nitrate, mellitic acid, Cl2012H.6, is obtd-... 

In more recent times Juettner [18] has worked extensively on the oxidation of various types of coal, including charcoal. He examined the action of various oxidizing agents such as potassium permanganate in an alkaline medium and nitric acid. On such oxidation of the charcoal obtained by carbonization of cellulose at 1000°C mellitic acid in a yield of 25 % by weight resulted. 

Under similar conditions fluorene gives mellitic acid in a yield of about 45%, while hexaethylbenzene yields almost exclusively carbon dioxide, without mellitic acid. The experiments outlined above point to the existence of condensed aromatic rings in charcoal. This structure of charcoal has been definitely proved by infra-red... 

More compounds have been identified in the neutral oxygen methyl ester fraction, shown in Figure 9, than in either the alkaline or acidic oxygen reactions. In addition to the products found in the alkaline oxygen reaction, the methyl ether ester of p-hydroxybenzoic acid and the methyl ester of mellitic acid are present. The acidic oxygen methyl ester fraction, also shown in Figure 9, qualitatively resembles the alkaline oxygen reaction. All the acids found in this latter reaction, except benzoic, are found in this fraction. The methyl ether ester of dehydrodivanillic acid or the methyl... 

In the methyl ester fraction of the spent acid from the nitric acid reaction (Figure 10), the methyl ether esters of p-hydroxybenzoic, vanillic, and syringic acids and the methyl esters of benzoic acid and the di- and tricarboxybenzenes have been found. These compounds are also present in the chromatogram of the basic extract, as are the methyl esters of the tetracarboxybenzenes and mellitic acid. In addition, dehydrodivanillic acid or pentacarboxybenzene or both are present in both chromatograms... 

Figure 6.3 Reproducibility of SDS-protein separations utilizing a replaceable polymeric gel. The peaks correspond to mellitic acid (1), a-lactalbumin (2), carbonic anhydrase (3), ovalalbumin (4), bovine serum albumin (5), phosphorylase b (6), /3-galactosidase (7), and myosin (8). (From Ref. 53.)...

Burdon542 has surveyed the current hypotheses for the structure of humic substances and has concluded that the various products from chemical degradations and NMR data are all consistent with their being mixtures of plant and microbial materials and their microbial degradation products. The examination of soil carbohydrates, proteins, lipids, and aromatics supported this view the presence of colour, fluorescence, ESR signals, mellitic acid, and other features do not contradict it. Regarding the Maillard reaction, some free monosaccharides and the necessary amino species are present in soil, so it may proceed, but only to a small extent it is not a major process. However, in marine environments, the relative abundance of carbohydrates and proteins makes them more probable precursors of humic substances than lignin or polyphenols. 

Various organic plasticizers having boiling points over 300 °C are available, such as di(2-ethylhexyl) phthalate (4a), di(2-ethylhexyl) adipate (8), oligomers formed from dicarboxylic acids and diols with molecular weights ranging up to 3500, esters of tri-mellitic acid, epoxidised fatty acids or organic phosphates, such as tris(2-ethylhexyl) phosphate (9) or (2-ethylhexyl) diphenyl phosphate (10). Most phosphates also function as flame retardants and some, such as 10, are smoke suppressants as well (Meier, 1990). 

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