Aromatic Hydroxycarboxylic Acids Research Articles

Mass spectral characterisation of a polar, esterified fraction of an organic extract of an oil sands process water.

Characterising complex mixtures of organic compounds in polar fractions of heavy petroleum is challenging, but is important for pollution studies and for exploration and production geochemistry. Oil sands process-affected water (OSPW) stored in large tailings ponds by Canadian oil sands industries contains such mixtures. A polar OSPW fraction was obtained by silver ion solid-phase extraction with methanol elution. This was examined by numerous methods, including electrospray ionisation (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) and ultra-high-pressure liquid chromatography (uHPLC)/Orbitrap MS, in multiple ionisation and MS/MS modes. Compounds were also synthesised for comparison. The major ESI ionisable compounds detected (+ion mode) were C15-28 SO3 species with 3-7 double bond equivalents (DBE) and C27-28 SO5 species with 5 DBE. ESI-MS/MS collision-induced losses were due to water, methanol, water plus methanol and water plus methyl formate, typical of methyl esters of hydroxy acids. Once the fraction was re-saponified, species originally detected by positive ion MS, could be detected only by negative ion MS, consistent with their assignment as sulphur-containing hydroxy carboxylic acids. The free acid of a keto dibenzothiophene alkanoic acid was added to an unesterified acid extract of OSPW in known concentrations as a putative internal standard, but attempted quantification in this way proved unreliable. The results suggest the more polar acidic organic SO3 constituents of OSPW include C15-28 S-containing, alicyclic and aromatic hydroxy carboxylic acids. SO5 species are possibly sulphone analogues of these. The origin of such compounds is probably via further biotransformation (hydroxylation) of the related S-containing carboxylic acids identified previously in a less polar OSPW fraction. The environmental risks, corrosivity and oil flow assurance effects should be easier to assess, given that partial structures are now known, although further identification is still needed.

Spectroscopic studies of oxo-centered, carboxylate-bridged, trinuclear mixed-valence iron (ІІІ, ІІІ, ІІ) complexes with aromatic hydroxycarboxylic acids

New type of oxo-centered, carboxylate-bridged, trinuclear, mixed-valence iron complexes of the general formula [Fe3O(OOCR)3(OOCR*)3L3] (where R=C13H27 or C15H31 and R*=C6H4(OH), (R′); C6H5CH(OH), (R″) or (C6H5)2C(OH), (R‴) and L=Methanol) were synthesized by the reaction of [Fe3O(OOCCH3)6(H2O)3] with straight chain carboxylic acids and aromatic hydroxycarboxylic acids. These were characterized by elemental analyses, spectral (electronic, infrared, Mössbauer, FAB mass and powder XRD) studies, conductance and magnetic susceptibility measurements. Infrared spectra suggested bidentate and bridging mode of coordination of both the carboxylate and hydroxycarboxylate anions along with Fe3O vibrations in the complexes. Mössbauer parameters indicated the presence of high-spin Fe(ІІ) (S=2) and high-spin Fe(ІІІ) (S=5/2) centers in the complexes, confirming the valence-localized type of species. An intervalence-transfer band observed at 13,690–13,850cm−1 range in the room-temperature electronic spectra of the complexes also suggested the complexes containing iron in mixed-valence state. Trinuclear nature of the complexes was confirmed by their FAB mass spectra. Magnetic moment values displayed octahedral geometry around each iron in the complexes and a net anti-ferromagnetic exchange coupling via μ-oxo atom related to mixed-valence pairs. A plausible structure for these complexes has been established on the basis of spectra and magnetic moment data.

Bupivacaine salts of diflunisal and other aromatic hydroxycarboxylic acids: Aqueous solubility and release characteristics from solutions and suspensions using a rotating dialysis cell model

In the search for poorly soluble bupivacaine salts potentially enabling prolonged postoperative pain relief after local joint administration in the form of suspensions the solubility of bupivacaine salts of diflunisal and other aromatic hydroxycarboxylic acids were investigated together with the release characteristics of selected 1:1 salts from solutions and suspensions using a rotating dialysis cell model. The poorest soluble bupivacaine salts were obtained from the aromatic ortho-hydroxycarboxylic acids diflunisal, 5-iodosalicylic acid, and salicylic acid (aqueous solubilities: 0.6–1.9 mM at 37 °C). Diffusant appearance rates in the acceptor phase upon instillation of solutions of various salts in the donor cell applied to first-order kinetics. Calculated permeability coefficients for bupivacaine and the counterions diflunisal, 5-iodosalicylic acid, and mandelic acid were found to be correlated with the molecular size of the diffusants. Release experiments at physiological pH involving suspensions of the bupivacaine–diflunisal salt revealed that at each sampling point the diflunisal concentration exceeded that of bupivacaine in the acceptor phase. However, after an initial lag period, a steady state situation was attained resulting in equal and constant fluxes of the two diffusants controlled by the permeability coefficients in combination with the solubility product of the salt. Due to the fact that the saturation solubility of the bupivacaine–salicylic acid salt in water exceeded that of bupivacaine at pH 7.4, suspensions of the latter salt were unable to provide simultaneous release of the cationic and anionic species at pH 7.4. The release profiles were characterised by a rapid release of salicylate accompanied by a much slower appearance of bupivacaine in the acceptor phase caused by precipitation of bupivacaine base from the solution upon dissolution of the salt in the donor cell.

New water-soluble cutting fluid additives derived from aromatic hydroxycarboxylic acids

A variety of alkoxyaromatic carboxylic acids and acyloxyaromatic carboxylic acids were prepared from various hydroxyaromatic carboxylic acids, and screened for anti-rust properties, lubrication properties and antimicrobial activity in spent coolants of water-soluble cutting fluids. The triethanolamine salt of alkoxydiphenyl carboxylic acids showed good anti-rust activity and lubrication properties. The triethanolamine salts ofp-alkoxyphenyl propionic acid showed good antimicrobial activity together with good anti-rust properties and lubrication properties.

Studies on Derivatives of Aromatic Hydroxycarboxylic Acids as Antioxidant. II.

The effect of aromatic hydroxycarboxylic acids as antioxidant and the influence of the metallic ion (Fe (II)) on the dissolved oxygen in O/W type emulsion was investigated by a polarographic Beckman Oxygen Analyzer, Model 777.Soybean oils with different POV (peroxide value) and water were emulsified into O/W type emulsion using Tween-40 as the emulsifier, and the variation of dissolved oxygen was measured in the presence of the Fe (II) ion.In order to evaluate the effect of aromatic hydroxycarboxylic acids, an acid solution was added to the emulsion, then, the metallic solution was added to the same emulsion, and the variation in the dissolved oxygen was measured.The results of these measurements revealed that the oxygen absorption increased in the presence of Fe (II) and, that the deteriorating effect was suppressed by the addition of these acids.When comparing the stabilizing effect of 2-hydroxybenzoic 2, 4-and 2, 6-dihydroxybenzoic acids with those of 2, 5-, 3, 4-, 3, 5-dihydroxybenzoic and gallic acids, the former are seen to function as the chelating agent, the latter are clearly seen to function as the radical inhibitor.

Studies on Derivatives of Aromatic Hydroxycarboxylic Acids as Antioxidant. I.

1-Palmitoyl-3- (3', 4', 5'-trimethoxybenaoyl) glycerol (IV), 1-palmitoyl-3-galloyl glycerol (VII) and 1-galloyl glycerol (X) were prepared according to the method shown in Scheme-1, 2 and 3. The structures were confirmed by means of IR, NMR and chemical analysis. The antioxidation effect of these compounds for the soybean oil has been evaluated by the A.O.M. and the Shaal Oven Tests. The effect of 1-galloyl glycerol was found to be much larger than that of propyl gallate.

Antimicrobial activity of metal chelates of salts of 8-quinolinols with aromatic hydroxycarboxylic acids.

Thirty-seven metal chelate complexes of salts of 8-quinolinols with aromatic hydroxycarboxylic acids were screened by the disc-plate method against strains of five bacteria and five fungi. The copper (II) chelates of 8-quinolinolium salicylate and 8-quinolinolium-3'-hydroxy-2'-naphthoate showed outstanding antifungal and good antibacterial properties and appear to be potentially more economical than copper (II) 8-quinolinolate.

Antimicrobial Activity of Metal Chelates of Salts of 8-Quinolinols with Aromatic Hydroxycarboxylic Acids

Thirty-seven metal chelate complexes of salts of 8-quinolinols with aromatic hydroxycarboxylic acids were screened by the disc-plate method against strains of five bacteria and five fungi. The copper (II) chelates of 8-quinolinolium salicylate and 8-quinolinolium-3'-hydroxy-2'-naphthoate showed outstanding antifungal and good antibacterial properties and appear to be potentially more economical than copper (II) 8-quinolinolate.

Interaction between Pyrazinamide and Sodium p-Aminosalicylate or Sodium Hydroxybenzoates in Aqueous Solution

Alkali salts of some aromatic hydroxycarboxylic acids are effective in increasing the solubility of pyrazinamide in water and the use of sodium p-aminosalicylate (PAS-Na) results in the formation of a yellow solution of pyrazinamide-PAS-Na complex. It has been found from examination of absorption spectrum in the visible range that the coloration is due to the formation of a 1 : 1 molecular compound of pyrazinamide and PAS-Na in aqueous solution. It was also found that sodium o-, m-, and p-hydroxybenzoates also form 1 : 1 molecular compound with pyrazinamide. There is a linear relationship between increased solubility of pyrazinamide per mole of aromatic hydroxycarboxylic acid added and equilibrium constant of the molecular compound thereby formed. The equilibrium constants obtained in the present series of work were larger than the values calculated from the solubility increase and some considerations were made on the reason for this difference.