Salicylic acid extraction

Evaluation of Distribution Parameters. The fraction of salicylic acid extracted (%E) was found to be proportional to the equilibrium fraction (a0) of the un-ionized neutral form present in the pH range 1.65-3.01, as shown in Table I. To analytically describe the partition... 

Table I. Relation of the Fraction of Salicylic Acid Extracted (%E) to the Equilibrium Fraction (a0) of die Un-ionized Neutral Form in the pH Range 1.65-3.01...

Salicylic acid extractions from inorganic electrolyte solutions of 0.1 ionic strength yielded about 10 more extraction efficiency than those from water solutions, probably attributable to a salting-out effect. 

Despite these potential side effects the use of the RDC technique has permitted the accumulation of important information on the kinetic properties of extraction systems. So, a significant and noteworthy example is provided by a kinetic study [19] of salicylic acid extraction by liquid hydrocarbons. In this latter work, it was... 

Methyl salicylate is produced synthetically for commercial purposes by the esterification of salicylic acid with methanol or by extraction by steam distillation of wintergreen leaves or sweet birch bark. The source, natural or synthetic, is declared on the label. The methyl salicylate NF must assay not less than 98.0% and not more than 100.5% and be processed by Good Manufacturing Practice described in USP (20). 

Coumarin, or extract of Tonka beans, which contain coumarin, may be detected as follows A small quantity of the essence is evaporated to dryness, the residue fused with caustic potash, saturated with hydrochloric acid and treated with a drop of ferric chloride solution. If coumarin be present, a violet colour due to the formation of salicylic acid, will be produced. 

Lemna obscura fronds contain high quantities of anthocyanln that are extractable by soaking the fronds In 0.1 M HC1. L. obscura growth in the culture dish bloassay was similar to that of L. minor and appeared to be more sensitive to low levels of allelochemlcals. Anthocyanln concentration was affected by low concentrations of salicylic acid (Table VIII). Final frond number and dry weight were consistently reduced by 100 pM and 500 pM concentrations of salicylic acid whereas anthocyanln formation was inhibited by 50 UM concentrations of salicylic acid and stimulated by 0.5 VM. 

Hok, B., Studies on the extraction of metal complexes. XV. The dissociation constants of salicylic acid, 3,5-dinitrobenzoic acid, and cinnamic acid and the distribution between chloroform-water and methyl isobutyl ketone (hexone)-water, Sv. Kem. Tidskr. 65, 182-194 (1953). 

In a static-culture-flask screening test, naphthalene (5 and 10 mg/L) was statically incubated in the dark at 25 °C with yeast extract and settled domestic wastewater inoculum. After 7 d, 100% biodegradation with rapid adaptation was observed (Tabak et al, 1981). In freshwater sediments, naphthalene biodegraded to c/5-1,2-dihydroxy-1,2-dihydronaphthalene, 1-naphthol, salicylic acid, and catechol. 

It seems unlikely that the allelopathic chemicals that may be extracted from plant material are actually those that reach the host plant, yet nearly all our information on allelopathic compounds is derived from extracts that have never been exposed to the soil. Some compounds, such as juglone, may remain unchanged in the soil under some circumstances ( ), but many compounds, such as ferulic or salicylic acid, are converted to other chemicals in the soil. 

Table III. Salicylic Acid Metabolite Production by a 50-65% Ammonium Sulfate Fraction Extracted from Oat Roots Exposed to...

Partial Purification of SA-GTase. Proteins extracted from oat roots Incubated for 20 h in salicylic acid were separated by salt precipitation and gel exclusion and anion exchange chromatography (Table IV). A 5 -fold purification of the SA-GTase was achieved with this... 

Figure 2. Reaction scheme for UDPG salioylio acid glucosyltrans-ferase extracted from oat roots incubated for 20 hr in solution containing salicylic acid.

Many medicines that we now use and often take for granted were based on the healing properties of plants and other natural sources known to traditional healers. Aspirin, or acetylsalicylic acid, is a chemically modified form of salicylic acid, a chemical extracted in the early 19 century from willow tree bark, which had been known for centuries to reduce fevers. Today, aspirin is chemically... 

Phenyl salicylate (salol) is manufactured by heating salicylic acid and phenol in the presence of phosphoms oxychloride for 4—5 hours at 110—115°C. The molten product is separated, mixed with water, dried, and distilled under vacuum. Another process involves the transesterification of a salicylate such as methyl, with phenol in the presence of an alkali or alkaline-earth phenate. Medicinally, phenyl salicylate was formerly used as an intestinal antiseptic. However, the main applications of phenyl salicylate have been related to the ability to absorb uv light over the wavelengths of 290—325 nm. As an effective uv-light absorber, phenyl salicylate was incorporated in alkyd paints, waxes, and polishes, but has been largely replaced in this application by less extractable, more effective compounds. The May 1996 price was 10.60/kg (18). 

In contrast, oral administration of a willow bark extract showed a low bioavailability of salicin (98). After ingestion of commercial sugar-coated tablets containing willow bark extract corresponding to a total amount of 54.9mg (0.192mmol) salicin, the serum of 12 volunteers showed a peak concentration of only 0.13 pg/mL salicylic acid this is only 5% of the serum... 

That s quite a claim for the little pill that was concocted in 1897 by Felix Hoffmann, a chemist working for the Bayer company in Germany. While Hoffmann did synthesize the first commercial sample of acetylsalicylic acid, as aspirin is known generically, he wasn t the first to produce the substance in the laboratory. That honor goes to Karl Friedrich Gerhardt, who, in 1853 at Montpellier University in France, concocted an impure version with an eye towards improving on the effects of salicylic acid, a commonly used painkiller. At the time salicylic acid was extracted from the leaves of the meadowsweet plant and used for the treatment of fevers and pain, particularly of the arthritic variety. But it had to be taken in... 

P. Vanloot, J. L. Boudenne, C. Brach-Papa, M. Sergent and B. Coulomb, An experimental design to optimise the flow extraction parameters for the selective removal of Fe(III) and Al(III) in aqueous samples using salicylic acid grafted on Amberlite XAD- and final determination by GF-AAS, J. Hazard. Mater., 147(1-2), 2007, 463-470. 

For many decades the pain relieving properties of willow bark extracts have been used in folk medicine (Fig. 1). Glycoside cleavage and oxidation is necessary for the biosynthesis of salicylic acid from the plant precursor p-D-glucopyranoside, the so-called saligenins. 

Solvent extraction offers unique advantages among separation techniques. A system based on extraction into a polymer [poly(vinyl chloride)] as solvent was examined here because of possible advantages in speedy simplicity, sample size, solvent handlingy etc.f especially when coupled with flow injection and an amperometric detector. Solutes examined included salicylic acid and 8-hydroxy quinoline. The apparatus typically consisted of 0.8-mm i.d. X 170-cm coiled tubing that could be connected directly to the injection loop of a flow-injection amperometric detector system containing a nickel oxide electrode. 

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