Salicylic acid, esterification with

In this reaction, the hydroxyl group (—OH) on the benzene ring in salicylic acid reacts with acetic anhydride to form an ester functional group. Thus, the formation of acetylsalicylic acid is referred to as an esterification reaction. This reaction requires the presence of an acid catalyst, indicated by the above the equilibrium... 

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). 

The esterification of the phenolic hydroxyl group in salicylic acid with acetic acid results not only in an... 

The esters of salicylic acid account for an increasing fraction of the salicylic acid produced, about 15% in the 1990s. Typically, the esters are commercially produced by esterification of salicylic acid with the appropriate alcohol using a strong mineral acid such as sulfuric as a catalyst. To complete the esterification, the excess alcohol and water are distilled away and recovered. The cmde product is further purified, generally by distillation. For the manufacture of higher esters of salicylic acid, transesterification of methyl salicylate with the appropriate alcohol is the usual route of choice. However, another reaction method uses sodium salicylate and the corresponding alkyl halide to form the desired ester. 

Since salicylic acid has both an alcohol functional group and a carboxylic acid functional group, it can undergo two different esterification reactions depending on which functional group reacts. For example, when treated with ethanoic acid (acetic acid), salicylic acid behaves as an alcohol and the ester produced is acetylsalicylic acid (aspirin). On the other hand, when reacted with methanol, salicylic acid behaves as an acid and the ester methyl salicylate (oil of wintergreen) is produced. Methyl salicylate is also an analgesic and part of the formulation of many liniments for sore muscles. What are the structures of acetylsalicylic acid and methyl salicylate ... 

Recently [43] Gao et al. applied a zeolite-fiOlled polyvinyl alcohol (PVA) membrane in esterification and acetalization reactions. Zeolites NaA, KA and CaA as well as NaX were loaded into PVA up to 27 wt% and the composites tested in selective water removal during reaction. A pervaporation cell with a membrane area of 22.9 cm was coimected to a collection system kept at a vacuum of 0.1 mm Hg. A sulfonated resin was used as Bronsted acid catalyst in the esterification mixture (120 ml). Figure 28 shows the progress of the esterification of salicylic acid and methanol at 60°C. The reaction is accelerated considerably as a result of the water removal. 

S, Methyl Salicylate. 2-Hydroxybenzoic acid methyl ester wintergreen oil betula oil sweet birch oil teaberry oil. C H,03 mol wt 152.14. C 63.15%, H 5.30%. O 31.55% Present in leaves of Oaultherta procumbent L-> Ericaceae, in the bark of Betula lenta L., Betulaceae, hut mostly prepd by esterification of salicylic acid with methanol. The product of commerce is about 99% pure. 

It may be prepared by the esterification of acetyl salicylic acid and paracetamol with the elimination of a mole of water. 

Methyl 2-hydroxybenzoate (methyl salicylate) has the odor of oil of wintergreen.This ester is prepared by the Fischer esterification of 2-hydroxybenzoic acid (salicylic acid) with methanol. Draw a structural formula of methyl 2-hydroxybenzoate. 

Gao, Yue, and Li (1996) studied the same reaction using a zeolite A-PVA composite membrane (at temperatures ranging from 20 to 50 °C). In this work, together with the pervaporation-aided catalytic esterification of acetic acid with ethanol, the reaction between salicylic acid with methanol was also treated. Among other results, it showed that the continuous removal of water from the system displaced the equilibrium limit (79%), making possible a 95% conversion, when using PVA, PVA -I- KA, and PVA -I- CaA membranes for 20.0, 11.3, and 10.0 h, respectively. 

Bochner, M., S. Gerber, W. Vieth A. Rodger (1%5) Ion exchange resin-catalyzed esterification of salicylic acid with methanol. Industrial Engineering Chemistry Fundamentals, 4, 314-317,ISSN 01%-4313. 

Methyl salicylate will be prepared from salicylic acid, which is esterified at the carboxyl group with methanol. You should recall from your organic chemistry lecture course that esterification is an acid-catalyzed equilibrium reaction. The equilibrium does not lie far enough to the right to favor the formation of the ester in high yield. More product can be formed by increasing the concentrations of one of the reactants. In this experiment, a large excess of methanol will shift the equilibrium to favor a more complete formation of the ester. 

Write a mechanism for the acid-catalyzed esterification of salicylic acid with methanol. You may need to consult the chapter on carboxylic acids in your lecture textbook. 

Figure 14 4 Acetylation of salicylic acid to produce aspirin. The synthesis of aspirin is classified as an esterification reaction. Salicylic acid is treated with acetic anhydride, an acid derivative, causing a chemical reaction that turns salicylic acid s phenol group into an acetyl group, (R-OH R-OCOCH3). This process yields aspirin and acetic acid, which is considered a byproduct of this reaction. Small amounts of sulphuric acid (and occasionally phosphoric acid) are almost always used as a catalyst.

An additional method of ACEC synthesis was based on hydroxybenzoic acids as the starting materials [32]. The synthesis starts from esterification of the acid with 3-cyclohexenyl-1-methyl alcohol. The following hydroxybenzoic acids were used 2-hydroxybenzoic (salicylic), 2,4-di-hydroxybenzoic ( 3-resorcylic) and 3,4,5-trihydroxybenzoic (gallic) acid. The phenolic hydroxyls in the cy-clohexenylmethyl esters were transformed in glycidyl ethers in the usual way (reaction with excess ECH followed by dehydrochlorination). Eventually, epoxidation with PAA was carried out (Scheme 51). The epoxide groups content in the ACECs thus prepared was above 85% of the calculated value. 

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