Photolytic and photocatalytic degradation of nitrofurantoin and its photohydrolytic products
[Display omitted] •Photocatalyzed decomposition of nitrofurantoin was compared to its photolysis.•The first stage involved photoisomerization and photohydrolysis in both cases.•The photoisomer underwent dark hydrolysis too, giving two primary intermediates.•Aerobic photocatalysis decomposed both nit...
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| Published in: | Journal of photochemistry and photobiology. A, Chemistry. Vol. 386; p. 112093 |
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| Main Authors: | , , , , , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
Elsevier B.V
01-01-2020
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| Subjects: | |
| Online Access: | Get full text |
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| Summary: | [Display omitted]
•Photocatalyzed decomposition of nitrofurantoin was compared to its photolysis.•The first stage involved photoisomerization and photohydrolysis in both cases.•The photoisomer underwent dark hydrolysis too, giving two primary intermediates.•Aerobic photocatalysis decomposed both nitrofuraldehyde and aminohydantoin.•Several intermediates were detected to reveal degradation pathways.
TiO2 based photocatalytic degradation of nitrofurantion (NFT), a widely used drug, and its primary decomposition products, nitrofuraldehyde (NFA) and aminohydantoin (AHD) was investigated and compared to their photolysis in aerobic systems. UV–vis spectrophotometry, pH, IC, and HPLC measurements were applied to follow the changes during the irradiations and subsequently, in the dark. After a fast anti→syn (or trans→cis) photoisomerization of NFT (giving i-NFT), a slower photohydrolysis of both isomers took place upon UV excitation, leading to the formation of NFA and AHD. i-NFT proved to be more reactive than NFT; it underwent hydrolysis in the dark, too. While photolysis could not totally convert NFT and i-NFT within 120 min, they disappeared within 90 min during the photocatalysis under the same irradiation conditions, along with the degradation of NFA and AHD, and the accumulation of a rather stable intermediate identified as 5-hydroxyfuran-2-carbaldehyde, formed from NFA. The direct photolysis of NFA also gave this characteristic intermediate along with its several derivatives formed via addition or condensation then redox transformations. They very slowly decomposed in photolysis, while totally disappeared during photocatalysis of NFA, producing polar aliphatic intermediates. Direct irradiation could not convert AHD, while photocatalysis led to its significant degradation in aerobic system. These results indicate that TiO2 based photocatalysis is suitable for the efficient decomposition of NFT and their photoderivatives. |
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| ISSN: | 1010-6030 1873-2666 |
| DOI: | 10.1016/j.jphotochem.2019.112093 |