Salicylic acid, solvent extraction using

Copper is widely distributed in Nature as metal, in sulfides, arsenides, chlorides, carbonates, and so on. It is extracted from ores, usually by wet processes, for example, by leaching with dilute sulfuric acid, or by solvent extraction using salicylal-doximes and similar ligands. Copper is refined by electrolysis. 

The handling and disposal problems associated with the use of liquid solvent extractors have resulted in increased attention to the separation and preconcentration of organic compounds in water by collection in synthetic polymers followed by elution with an organic solvent (2). For example, selective collection and concentration of organic bases on methylacrylic ester resin from dilute water samples have been reported (3). Such collection techniques are especially well-suited to flow-injection measurement techniques. In this study, ionizable organic analytes such as salicylic acid and 8-hydroxyquinoline (oxine) were extracted into a polymer and then back extracted by an aqueous solution. Amperometric measurement using a flow-injection technique was employed to monitor the process. 

By using experimentally obtained data for 1 mM salicylic acid, a plot of reciprocal analytical signal versus reciprocal a, yielded a linear relationship for the pH range 1.65-3.01. This result supported the solvent extraction model. The corresponding estimate of capacity ratio and distribution coefficient using this treatment was 8.5. 

Fogel et. ah (53) also developed a reversed phase HPLC method for the simultaneous assay of aspirin and salicylic acid in film-coated aspirin tablets. As little as 0.1% salicylic acid (relative to aspirin) can be quantitatively determined. Using a 5-microns octadecylsilane column with water-acetonitrile-phosphoric acid (76-24 0.5) as the mobile phase enabled the chromatographic separation to be completed in 4 minutes. Due to the slow rate of decomposition of aspirin to salicylic acid in the extraction solvent, acetonitrile-methanol-phosphoric acid (92 8 0.5), the analysis of many samples was routinely performed by means of automated HPLC equipment. 

Formation constants of 3d metal ions with A-m-tolyl-p-substituted benzohydroxamic acids and of rare earths with thenoylhydroxamic acid have been determined. Formation constants of proton and metal complexes of iV-phenyl-2-thenoyl- and A-p-tolyl-2-thenoyl-hydroxamic acids have also been determined. In addition, study has been made of the mixed ligand complexes involving nicotine- and isonicotino-hydroxamic acids. A method of extraction and spectrophotometric determination of vanadium with chlorophenylmethylbenzohydroxamic acid has also been published. It may be mentioned that hydroxamic acids (in particular, the A-phenylbenzohydroxamic acid) have been widely used as analytical reagents for metal ions. Solvent extraction of titanium by benzo- or salicyl-hydroxamic acid in the presence of trioctylamine in the form of coloured complexes has been reported. A-w-Tolyl-p-methoxybenzohydroxamic acid has been used for extraction and spectrophotometric determination of Mo and W from hydrochloric acid media containing thiocyanate. 

Solvent extraction has been described by Mnthnraman and Palanivelu (2005) for anionic dyes. In their study, tetrabutyl ammonium bromide (TBAB) in methylene chloride was used for selective extraction of dye from aqueous solution. The solvent could be regenerated after removal of the dyes, with minor loss in effectiveness. Various compounds were explored to strip the dyes from the organic phase. Salicylic acid in sodium carbonate solution proved to be most snccessfnl. In this case, dye recovery in aqueous solution up to 98% could be achieved. Mineral salts present did not affect the extraction process. 

Gregory and Feldstein (94) developed an ion-paired, reversed-phase HPLC method for individual Be vitamers extracted with sulphosalicylic acid from different foods. Using a ternary solvent program, elution of nutritionally active Be vitamers from the analytical column was complete within 30 min. PLP was determined as its hydroxysulfonate derivative, following postcolumn introduction of a buffered solution of sodium bisulfite. This method was found suitable for vitamin Be analysis in foods of both plant and animal origin. Recoveries for PLP and PL from pork loin were <90% it was suggested that these vitamers were not completely released from muscle proteins, even in the presence of 5% sulfo-salicylic acid. 

A further development in the description of the disease was reported by Robinson et al. (1979), who reported a patient, a female child of unrelated French-Canadian parents, who presented with metabolic acidosis, acetonuria and coma after a fever at 30 months of age. Her clinical condition deteriorated and she died with features of salicylism, including a serum salicylate of 20 mg dl A second child (female) born several years later to the same family subsequently presented at 1 year with fever, metabolic acidosis, vomiting and persistent tachypnoea. She had ketonuria, and an apparent serum salicylate of 11.2 mg dl despite having received no salicylates during the previous 6 days. GC-MS of urinary organic acids extracted using solvents revealed the presence of increased concentrations of lactate (510 mg per g of creatinine), 3-hydroxy-butyrate (2310 mg per g of creatinine), acetoacetate (2080 mg per g of creatinine), 2-methyl-3-hydroxybutyrate (480 mg per g of creatinine), 2-methylacetoacetate (572 mg per g of creatinine), 3-hydroxyisovalerate (470 mg per g of creatinine) and tiglylglycine (152 mg per g of creatinine). The apparent salicylate in serum was found to be due to acetoacetate. 

Titanium has been extracted from hydrochloric acid medium by HTTA (mixed with TBP) [7]. Titanium has been extracted from salicylate medium by using Aliquat 336 in xylene [8]. Solutions of HDEHP and other alkylphosphoric acids in benzene or other solvents have also been used for separation of Ti [9]. 

A similar hexone-thiocyanate process has been operated in the U.S.A., firstly by the Northwest Electrodevelopment Laboratories at Albany since 1952 and the Carborundum Metals Corporation plant near Akron, New York, since 1953. They use packed and unpacked columns and the difficulties associated with polymerization of thiocyanic acid were alleviated by using a solvent consisting of 80 per cent hexone and 20 per cent butyl acetate instead of solely hexone. > The zirconium product is precipitated as the acid sulphate, phthalate or salicylate, and a certain additional degree of purification is obtained at this stage. A typical analysis of pure zirconium oxide after hexone-thiocyanate extraction and salicylate precipitation is as follows ... 

---