Phenylacetic acid

Toxicity

Acute oral toxicity (LD50): 2250 mg/kg [Mouse].

Chemical properties

white crystals with a honey-like odour

Chemical properties

Phenylacetic Acid occurs in Japanese peppermint oil, in neroli oil, and in traces in rose oils. It is a volatile aroma constituent of many foods (e.g., honey). It forms colorless crystals (mp 78°C) that have a honey odor.
The common route to phenylacetic acid is conversion of benzyl chloride into benzyl cyanide by reaction with sodium cyanide, followed by hydrolysis. Because of its intense odor, phenylacetic acid is added to perfumes in small quantities for rounding off blossom odors. Addition to fruit aromas imparts a sweet honey note.

Chemical properties

Phenylacetic acid has a sweet, animal, honey-like odor in dilute solution. The odor is persistent and disagreeable in concentrated solution. It has a sweet, honey-like flavor at high levels. At low levels, it is a sweetener.

Occurrence

Reported found among the constituents of a few essential oils: tobacco, Rosa centifolia, Bulgarian rose, orange flowers absolute, neroli and Mentha arvensis of Japanese origin; also reported present among the volatile constituents of cocoa. Also reported found in guava, papaya, raspberry, strawberry, cooked potato, tomato, peppermint oil, pepper, rye bread, cheddar cheese, Swiss cheese, Gruyere cheese, boiled mutton, beer, cognac, cider, sherry, grape wines, white wine, sake, cocoa, tea, honey soy protein, passion fruit, starfruit, mango, mushroom, malt, wort, roasted chicory root, naranjilla fruit, choke berry, sea buckthorn and Chinese quince.

The Uses of Phenylacetic acid

Phenylacetic Acid is a flavoring agent that is crystalline (white, glis- tening), with unpleasant, persisting odor resembling geranium leaf and rose when diluted. it is soluble in most fixed oils and glycerin, slightly soluble in water, and insoluble in mineral oil. it is obtained by chemical synthesis. it is also termed a-toluic acid.

The Uses of Phenylacetic acid

Phenylacetic Acid is used in the synthesis of Diclofenac (D436450) and its metabolite 4'-Hydroxydiclofenac (H825225), which is the principal human metabolite of Diclofenac.

The Uses of Phenylacetic acid

Phenylacetic acid?has strong fixative agent and can be directly used in low-or-middle-level soap, cosmetics essences. It is usually to confect the substitute for civetta with indole quinoline type and used in acacia, sweet-scented osmanthus, rose, hosta and other floral essences.

Indications

For use as adjunctive therapy for the treatment of acute hyperammonemia and associated encephalopathy in patients with deficiencies in enzymes of the urea cycle.

Background

Phenylacetic acid is an organic compound containing a phenyl functional group and a carboxylic acid functional group. It is a white solid with a disagreeable odor. Because it is used in the illicit production of phenylacetone (used in the manufacture of substituted amphetamines), it is subject to controls in countries including the United States and China.

Definition

ChEBI: A monocarboxylic acid that is toluene in which one of the hydrogens of the methyl group has been replaced by a carboxy group.

Preparation

By the treatment of benzyl cyanide with dilute sulfuric acid and other processes.

Aroma threshold values

Detection: 1 ppm

Taste threshold values

Taste characteristics at 30 ppm: sweet, floral, chocolate, honey and tobacco.

Synthesis Reference(s)

The Journal of Organic Chemistry, 20, p. 440, 1955 DOI: 10.1021/jo01122a005
Tetrahedron Letters, 26, p. 2027, 1985 DOI: 10.1016/S0040-4039(00)94770-1

Flammability and Explosibility

Non flammable

Safety Profile

Moderately toxic by ingestion, subcutaneous, and intraperitoneal routes. An experimental teratogen. Combustible liquid. Used in production of drugs of abuse. When heated to decomposition it emits acrid smoke and irritating fumes

Metabolism

Phenylacetate esterases found in the human liver cytosol. Human plasma esterase also hydrolyze phenylacetate. Phenylacetate hydrolysis involved arylesterase in plasma, both arylesterase and carboxylesterase in liver microsomes and carboxylesterase in liver cytosol. Plasma hydrolysis is less important and overall esterase activity is lower in humans than in the rat.

Metabolism

Phenylacetic acid is conjugated in man and the chimpanzee, but probably in no other species, with glutamine. In most other animals, except the hen, it behaves like benzoic acid, forming glycine and glucuronic acid conjugates. In the hen, it conjugates with ornithine, forming phenacetornithuric acid. Phenacetylglutamine and its addition compound with urea were isolated from human urine alter the administration of phenylacetic acid (Williams, 1959).

Purification Methods

Crystallise the acid from pet ether (b 40-60o), isopropyl alcohol, 50% aqueous EtOH or hot water (m 77.8-78.2o). Dry it in vacuo. It can be distilled under a vacuum. [Beilstein 9 II 294, 9 III 2169.]