salicylic acid

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salicylic acid

or

2-hydroxybenzoic acid,

C6H4(OH)CO2H, a colorless, crystalline organic carboxylic acid that melts at 159°C;; it is soluble in ethanol and ether but is only slightly soluble in water. It is prepared commercially by heating sodium phenolate (the sodium salt of phenol) with carbon dioxide under pressure to form sodium salicylate, which is treated with sulfuric acid to liberate salicylic acid. Salicylic acid and its derivatives are toxic when consumed in large amounts. Sodium salicylate is used to a small extent as a food preservative and as an antiseptic in mouthwashes and toothpastes. The major use of salicylic acid is in the preparation of its ester derivatives; since it contains both a hydroxyl (−OH) and a carboxyl (−CO2H) group, it can react with either an acid or an alcohol. The hydroxyl group reacts with acetic acid to form the acetate ester, acetylsalicylic acid (see aspirinaspirin,
acetyl derivative of salicylic acid (see salicylate) that is used to lower fever, relieve pain, reduce inflammation, and thin the blood. Common conditions treated with aspirin include headache, muscle and joint pain, and the inflammation caused by rheumatic fever and
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). Several useful esters are formed by reaction of the carboxyl group with alcohols. The methyl ester, methyl salicylate (also called oil of wintergreen since it produces the fragrance of wintergreen), is formed with methanol; it is used in food flavorings and in liniments. The phenyl ester, phenyl salicylate, or salol, is formed with phenol; it is used in medicine as an antiseptic and antipyretic. This ester hydrolyzes, not in the acidic stomach, but in the alkaline intestines, releasing free salicylic acid. The menthyl ester, menthyl salicylate, which is used in suntan lotions, is formed with menthol.

Salicylic Acid

 

(o-hydroxybenzoic acid), the simplest aromatic hydroxycarboxylic acid. A colorless crystalline compound that is poorly soluble in water but readily soluble in organic solvents. Melting point, 159°C; boiling point, 211°C (at 2.66 kilonewtons per sq m).

Salicylic acid is widespread in nature, especially in the form of the glycoside of its methyl ester, methyl salicylate. It is usually produced industrially by carboxylation of phenol (the Kolbe-Schmitt reaction). Salicylic acid has weak antiseptic and irritant properties and, at high concentrations, keratolytic properties. It is used topically in salve, paste, powder, and solution form for treating skin ailments. It is an ingredient of Las-sar’s paste, galmanin powder, and corn lotion and plaster. The sodium salt of salicylic acid (sodium salicylate), the amide (sali-cylamide), and acetylsalicylic acid (aspirin) are used as antipyretic, antirheumatic, anti-inflammatory, and analgesic agents. The phenyl ester of salicylic acid is used as an antiseptic, and p-aminosalicylic acid (PAS) is used as an antituberculosis drug.

Because of its antiseptic action, salicylic acid is used in the preservation of foods. Its esters are used in the manufacture of azo dyes and odoriferous substances, and the acid itself is used for the colorimetric identification of iron and copper and for the separation of thorium from other elements.

salicylic acid

[¦sal·ə¦sil·ik ′as·əd]
(organic chemistry)
C6H4(OH)COOH White crystals with sweetish taste; soluble in alcohol, acetone, ether, benzene, and turpentine, slightly soluble in water; discolored by light; melts at 158°C; used as a chemical intermediate and in medicine, dyes, perfumes, and preservatives.

salicylic acid

a white crystalline slightly water-soluble substance with a sweet taste and bitter aftertaste, used in the manufacture of aspirin, dyes, and perfumes, and as a fungicide. Formula: C6H4(OH)(COOH)
References in periodicals archive ?
The studied treatments at the two regions were: (1) vitamin C (0 and 400 ppm as a foliar spray); and (2) salicylic acid (0 and 400 ppm as a foliar spray) were applied after 60, 90 and 120 days from sowing.
From the data in Table (1), it is obvious that, spraying coriander plants growing at North Sinai (saline soil) with ascorbic acid, salicylic acid or ascorbic acid + salicylic acid had a stimulator effect on survival percentage.
Plant height, number of branches, number of umbels increased with application of the mixture of ascorbic acid and salicylic acid followed by ascorbic acid and salicylic acid then control in both regions.
85] mentioned that ascorbic acid or salicylic acid treatments reduced the severity of salt stress as they showed best results on seedling growth, fresh and dry matter production of pumpkin under non-saline and saline environments.
Salicylic acid can be performing as growth regulator [64] and has been known as an important molecular signal in the plant reaction for the response to environmental stresses [95] that have desirable effects on plant growth and development [68].
Table (3) show that seed essential oils percentages from plants sprayed with ascorbic acid were higher than those of plants treated with ascorbic acid + salicylic acid and salicylic acid, whereas control plants have lower values.
Improvement of essential oil percentage and yield per plant in response to salicylic acid application has been reported in basil and marjoram [45].
Spray of salicylic acid after the exposure to salinity stresses increases survival plants and decreases the severity of the stress injury in rosemary seedlings [79].
Data presented in Tables (1-3) show that all interaction treatments between foliar spray with ascorbic acid, salicylic acid and ascorbic acid + salicylic and tow locations caused an increase in plant height, number of branches, number of umbels, weight of seeds and straw (g/plant or kg/feddan) as well as seed and straw essential oil (% or L/feddan) in both regions compared to untreated plants of each region alone, except coriander straw (kg/feddan) under North Sinai alone, with each of ascorbic acid and salicylic acid decreased weight of straw (kg/feddan) to be the smallest by using that of ascorbic acid.
Salicylic acid is a plant growth regulator known as an endogenous signaling molecule, which is involved in various physiological processes in plants, such as growth regulation, photosynthesis, stomatal conductance, nutrient uptake, plant water relations and mechanisms of plant resistance and tolerance to biotic and abiotic stresses [83, 55].
The results presented in Table (6) show that spraying coriander plants by vitamin C + salicylic acid gave the highest percent of linalool whereas, control plants gave the lowest percent in coriander seeds.
However spraying plants by salicylic acid gave the highest percentage of linalool.