- Substituent effect on the tautomerization of 1-arylazonaphthalen-2-ols by mass spectrometric analysis
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An electron-ionization (EI) mass spectra of a series of 1-arylazonaphthalen-2-ols was obtained for studying the substituent effect on the fragmentation. The correlation between the ratio, molecular ion and fragment ion, and Hammett's constants is applied to examine the effect of the substituent on the fragmentation. The negative correction between the ratio, Imolecular ion/(I171amu + I143amu + I115amu), and Hammett's constants indicates an electron-withdrawing group destabilized the molecular ion. An unusual long-range hydrogen transfer demonstrates an important role in the fragmentation process Mass spectra of a series of 1-arylazonaphthalen-2-ols were obtained for studying the substituent effect on the fragmentation. The correlation between the ratio of molecular ion and fragment ion, and Hammett's constants is applied to examine the effect of substituent on the fragmentation. The negative correction indicates an electron-with-drawing group destabilized the molecular ion. An unusual long-range hydrogen transfer demonstrates an important role in the fragmentation process.
- Lin, Shaw-Tao,Lin, Lee-Hui,Lin, Yi-Cang,Ding, Mei-Fan
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p. 257 - 262
(2015/03/31)
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- An environmentally friendly approach to the green synthesis of azo dyes in the presence of magnetic solid acid catalysts
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A solvent-free, efficient and green approach for the synthesis of azo dyes has been developed by the diazo coupling reactions of aromatic amines with β-naphthol in the presence of sulfonic acid functionalized magnetic Fe3O4 nanoparticles (Fe3O4@SiO2-SO3H) by a grinding method at room temperature. This green methodology aims to overcome the limitations and drawbacks of the previously reported methods such as low temperature, use of acids, alkalis and toxic solvents, instability of diazonium salts at room temperature, modest yields, and long reaction times. Moreover, the attractive advantages of the process include mild conditions with excellent conversions, simple product isolation process, inexpensive procedure and recyclability of the magnetic catalyst. This journal is
- Safari, Javad,Zarnegar, Zohre
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p. 17738 - 17745
(2015/06/15)
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- Cardanol-based bis(azo) dyes as a gasoline 91 colorant
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Novel bis(azo) dyes were successfully prepared from the coupling of either natural cardanol or its hydrogenated derivative with a series of diazotized aromatic amines and diamines. These new dyes were fully characterized by NMR, infrared and UV-visible spectroscopy and mass spectrometry. The dyes are highly soluble in a variety of common organic solvents and gasoline as a consequence of the cardanol unit. The physical properties of gasoline according to American Society for Testing and Materials standard were unaffected by the presence of the bis(azo) dye derived from 1-(4aminophenylazo)-2-naphthol at a concentration of 6 ppm and the dye showed excellent stability over a 3 month period. AOCS 2011.
- Paebumrung, Pimpaporn,Petsom, Amorn,Thamyongkit, Patchanita
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experimental part
p. 321 - 328
(2012/10/07)
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