Features of Phenolsulfonphthalein and Phenolphthalein Substituted at All Ortho-Positions of Phenols with Bromine.
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- TAMURA Zenzo
- School of Pharmaceutical Sciences, Showa University
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- TERADA Rimi
- School of Pharmaceutical Sciences, Showa University
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- OHNO Kennichi
- School of Pharmaceutical Sciences, Showa University
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- MAEDA Masako
- School of Pharmaceutical Sciences, Showa University
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Abstract
The influence of bromination at all the ortho-positions of phenols on the features of phenolsulfonphtalein and phenolphtalein was investigated. The absorption spectra of Bromphenol Blue (H2BPS) in phosphate buffers demonstrated the complete opening of the lactone ring to form yellow HBPS- at pH 1 where pK2=3.8. The reaction of hydroxide ion with blue BPS2- was found to produce colorless BPS(OH)3- required heating where pK3=9. On the contrary, the spectra of 3′,3″,5′,5″-tetrabromophenolphtalein (H2BPP) demonstrated that the lactone ring was very stable. More than 99.5% of BPP2- species consisted of a colorless lactone possessing two isolated phenol groups where pK1′=6.0 and pK2′=6.8; the reaction of hydroxide ion with BPP2- to produce BPP(OH)3- was slow where pK3=10.3. These results indicate the increased acidity of phenols and the greater tendency of the central carbon atom to act as an electron acceptor.
Journal
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- Analytical Sciences
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Analytical Sciences 15 (4), 339-342, 1999
The Japan Society for Analytical Chemistry
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Details 詳細情報について
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- CRID
- 1390001204254952448
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- NII Article ID
- 10002419357
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- NII Book ID
- AA10500785
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- COI
- 1:CAS:528:DyaK1MXisVSntL8%3D
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- ISSN
- 13482246
- 09106340
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- NDL BIB ID
- 4712328
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- Text Lang
- en
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- Data Source
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- JaLC
- NDL
- Crossref
- CiNii Articles
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- Abstract License Flag
- Disallowed