Brönsted and Lewis Acidity of Solid Nickel Sulfate
1971; Oxford University Press; Volume: 44; Issue: 4 Linguagem: Inglês
10.1246/bcsj.44.893
ISSN1348-0634
AutoresHideshi Hattori, Shun-itsu Miyashita, Kozo Tanabe,
Tópico(s)Mine drainage and remediation techniques
ResumoAbstract The distribution of Brönsted and Lewis acidities of nickel sulfates heat-treated at various temperatures in air or in a vacuum has been determined by observing the infrared spectra of pyridine adsorbed on the sulfates in the range 1300–1600 cm−1. It has been found that the Brönsted acidity increases with the rise of temperature of heat treatment in air, attains a maximum value at 250°C and then decreases, while the maximum of the Lewis acidity appears at a higher temperature (about 400°C), the sum of both acidities giving the total acidity measured by n-butylamine titration method. An experiment in a vacuum showed that Lewis acid is converted into Brönsted acid by the addition of water. The structural nature and the catalytic activity of the Brönsted and Lewis acid sites on nickel sulfate are discussed.
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