Simple and Precise Determination of Sulfuric Acid Ester in Unstabilized Cellulose Nitrate by Acetone-Hydrolysis– Lead Nitrate-Dithizone Titration Method
2000
Dawoud, A.-F. | Hamed, W.
Determination of sulfuric acid ester in all types of unstabilized cellulose nitrates is accomplished simply and precisely by adopting the acetone-hydrolysis method coupled with the determination of the sulfuric acid, resulting from hydrolysis, by the lead nitrate-dithizone titration method. The hydrolysis of sulfuric acid ester, RSO₄H, is effected to completion in pure acetone concentration (99–99.5%) at 45 °C for 3 h. The difference between the after-hydrolysis value and the zero-hydrolysis titer (in 90% acetone–water solutions) represents the amount of sulfuric acid liberated from the hydrolysis of sulfuric acid ester. The method is proved reliable for determining sulfuric acid ester in all types of unstabilized cellulose nitrates including those types containing low percentages of sulfuric acid ester such as the high-nitrogen content types.
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