Benzenehexacarboxylate

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. 

Sterically crowded acids, benzene-1.2,3,4-tetracarboxylicacid (l),133 benzenepentacarbox-ylic acid (2),136 and benzenehexacarboxylic acid (3),l3h l37 react with sulfur tetrafluoride in such a way that the internal carboxylic acid groups cyclize to form the l,1.3.3-tctrafluoro-1.3-dihydroisobenzofuran system while the external groups are converted into trifluoromethyl groups. 

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 well-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 (benzenehexacarboxylic acid) [517-60-2], C12H6012. 

Photoisomerization of (Z)-l-methylcyclo-octene 59aZ sensitized by chiral benzene(poly)carboxylates suffers significantly from steric effects. The photosensitization of 59aZ with bulky sensitizers leads to photostationary E/Z ratios and product ee s much lower than those obtained for less-hindered (Z)-cyclo-octene 38Z [158]. Enantiodifferentiating photoisomeri-zations of (Z,Z)-l,3-cyclo-octadiene and (Z,Z)-l,5-cyclo-octadiene (71Z and 78Z) have also been studied by using chiral benzene(poly)carboxylates at various temperatures [159]. Photosensitization of 71Z with hexa-(—)-menthyl benzenehexacarboxylate affords the (E,Z)-product 71E in 18% ee in pentane at —40 °C. In the photoisomerization of 78Z in pentane sensitized by (—)-menthyl benzoate, the (—j- Zj-isomer 78E is only slightly favored giving a 2% ee [126]. 

Some more complicated carbon oxides are known with carbon backbones familiar in organic chemistry. An example is benzenehexacarboxylic acid (mellitic acid) trianhydride, C12O9 = C6[(C0)20]3 (1), a white snblimable solid obtained by dehydration of the corresponding acid with acetyl chloride in a sealed tube at 160 °C. 

C18H14 p-terphenyl 92-94-4 211.85 1.1527 1 30686 C18H18012 benzenehexacarboxylic acid, hexamethyl ester 6237-59-8 2 S Tie ... 

Ageneraiized, weighted, noniinear ieast squares procedure is deveioped, based on pH titration data, for the refinement of octanoi-water partition coefficients (iog P) and ionization constants (pKa) of multiprotic substances. Ion-pair partition reactions, self-association reactions forming oligomers, and formations of mixed-substance complexes can be treated with this procedure. The procedure allows for CO2 corrections in instances where the base titrant may have CO2 as an impurity. Optionally, the substance purity and the titrant strength may be treated as adjustable parameters. The partial differentiation in the Gauss-Newton refinement procedure is based on newly derived analytical expressions. The new procedure was experimentally demonstrated with benzoic acid, 1-benzylimidazole, (+)-propranolol, and mellitic acid (benzenehexacarboxylic acid, AH6). 

SENSITIZERS AP = acetophenone BP = benzophenone A = acetone B = methyl 3,5-bis(trifluoromethyl)benzoate C = (-)-tetrabomyl 1,2,4,5-benzene tetracarboxylate D = (-)-hexakis(l-methylheptyl) benzenehexacarboxylate MB = methyl benzoate P = phenan-threne CNN = 1-cyanonaphthalene DCA = 9,10-dicyanoanthracene DCB = 1,4-dicyano-benzene DCN = 1,4-dicyanonaphthalene CuOTf = copper trifluoromethanesulfonate benzene complex TPT = tetraphenylpyrylium tetrafluoroborat. 

The oxides of carbon include the very stable and abundant CO and CO2, the unstable but isolable C3O2, and more complicated carbon oxides derived from organic backbones by removal of all hydrogen, for example, C12O9, from the complete dehydration of mellitic acid (benzenehexacarboxylic acid). Oxocarbon anions, C 0 , with apparent aromatic properties are also known. The properties of these carbon-oxygen compounds are summarized below. 

Benzenehexacarboxylic acid Mellitic acid Ci2HeOi2 617-60-2 342.169 nd (al) 287 dec vs H2O s EtOH, suit... 

The effect of different counterions on the viscosity stability of HMHEC-surfactant at pH 7 was also studied at 10% and 20% surfactant concentrations (Tables I and II). The most stable solutions were formed in the presence of fumaric and mellitic (benzenehexacarboxylic) acid. By contrast, citric and maleic acid occasioned relatively higher viscosity loss. These results indicate that the viscosity stability of a polymer-surfactant solution is dependent on the counterion configuration. It appears that flexible and difunctional anions, such as citrate, and cis-difunctional anions such as ma-leate ions can potentially bridge two surfactant head groups on a single... 

Benzenedi sul f on i chi ori de 1,2-Benzenedi t hi ol 1.3-Benzenedi t hi ol Benzeneet hanami ne Benzeneet hanami nd)ydrochl ori de Benzeneet hanol Benzenehexacarboxyl i oci d Benzenemet hanami ndiydrochl ori de Benzenemet hanesulf onyhlori de... 

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