THE ACTION OF X-RAYS ON DILUTE SOLUTIONS OF p-AMINOBENZOIC ACID
BS>The x-ray-induced hydroxylation of p-aminobenzoic acid (PABA) was studied in the presence and absence of oxygen, in neutral, and in 0.4 M sulfuric acid solution. The main product formed at pH 7.4 is 3-hydroxy-4-aminobenzoic acid (3-OH-PABA), There is no formation of p-aminosalicylic acid, but p- hydroxybenzoic acid and aniline are formed in trace amounts. In solutions flushed with pure 0 the yield of 3-OH-PABA was found to be 0.90 molecule/ 100 ev and the yield of total degradation 1.2 molecules/ 100 ev. In the absence of O these yields are reduced by a factor of 6. The data indicate that the degradation of PABA is due to OH radicals and that the O/sub 2/ radical is participating only in dismutations. The strong effect of O is ascribed to the trapping of electrons and H radicals, which in anoxia might be participating in back reactions, thus repairing the target molecules. In 0.4 M sulfuric acid the yield of total degradation was found to be 1.1 molecule and 0.9 molecule/ 100 ev in the presence and in the absence of 0 respectively, whereas the yield of 3-OH-PABA was less than 0.2. The mechanism of degradation is discussed. (auth)
- Research Organization:
- Norwegian Radium Hospital, Montebello, Norway
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-18-016110
- OSTI ID:
- 4076949
- Journal Information:
- Radiation Res., Journal Name: Radiation Res. Vol. Vol: 21
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
Similar Records
Observations on the mechanism of the protective action of sunscreens
Desulfatiglans anilini Initiates Degradation of Aniline With the Production of Phenylphosphoamidate and 4-Aminobenzoate as Intermediates Through Synthases and Carboxylases From Different Gene Clusters