4-Aminobenzoic acid

  • Para-aminobenzoic acid
  • 4-aminobenzoic
  • P- carboxyaniline

D02BA01

White to pale yellow, almost odorless solid

Fixed

1.38 g · cm -3 ( 20 ° C)

188.5 ° C

37.06 MPa ( 25 ° C)

2.38

Poorly in water ( 6.11 g · l-1 at 30 ° C)

  • 2850 mg · kg -1 ( LD50, mouse, oral)
  • 1000 mg · kg -1 ( LD50, dog, oral)

Template: Infobox chemical / molecular formula search available

P-aminobenzoic acid (PABA ) is an organic carboxylic acid, a block of folic acid and is often associated with the B vitamins, however, is not a vitamin. For many bacteria growth is an important substance which is required for the production of folic acid. This process can be disturbed by the similarly constructed sulfonamides. These compounds used as drugs act as an antimetabolite, prevent the production of folic acid for restricting the proliferation of bacteria. Except for the p-aminobenzoic acid (4- aminobenzoic acid ), there are two further forms of positional isomers, namely, the anthranilic acid (2- aminobenzoic acid ) and 3 -aminobenzoic acid.

Properties

P-aminobenzoic acid form of colorless crystals, which are soluble in hot water, ethanol, ether, glacial acetic acid. It is easily oxidized, such as with iron ( III) salts; in the air or on exposure to light easily enters yellowish- red discoloration. Bacteria require p -aminobenzoic acid as essential growth substance for the synthesis of folic acid. Baker's yeast contains about 5-10 ppm of p -aminobenzoic acid. The biosynthesis takes place from chorismic and glutamate.

Use

As a starting material for the synthesis of azo dyes, folic acid, local anesthetics, and as UV absorber (UV -B filters ) are used in sunscreens ( use concentration 3-5 %). Also p-aminobenzoic acid is sold under the name PABA as a dietary supplement.

Toxicology

P- aminobenzoic acid shows low acute toxicity; no indications were found on carcinogenicity. Sensitization tests on guinea pigs revealed no evidence of a sensitizing effect. p-aminobenzoic acid is not absorbed through the skin. After ingestion occur as the main metabolite p- aminohippuric acid (PAH ) and p- Acetylaminohippursäure (4- Acetamidohippursäure, PAAHA ) on.

CAS registry number PubChem Anatomical Therapeutic Chemical Classification System Vapor pressure Sulfonamide (medicine)
14005
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