A Study of the Sulphate Ester of Unstabilized Cellulose Acetate

Keirstead, Karl F.; Myers, John

doi:10.1139/v54-074

Cited by 9 publications

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“…T h e preparation of the cellulose acetate sulphate and the determination of sulphate content have been described previously (3). A known weight of damp cellulose acetate sulphate (approximately 1.5 gm.…”

Section: Methodsmentioning

confidence: 99%

Hydrolysis of Cellulose Acetate Sulphate in Acetone

Keirstead¹,

Myers²

1954

Can. J. Chem.

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When cellulose acetate sulphate is dissolved in acetone the hydrolysis of the sulphate ester is rapid compared with that of the acetate ester. In 70% acetone the relative rates are reversed. Hydrolysis of the sulphate ester in acetone is greatly affected by the temperature. At 25°C. or greater the hydrolysis is conlplete after 24 hr. A potentiometric titration method has been developed for the estimation of sulphuric acid in the presence of smaller amounts of acetic acid. INTRODUCTIONT h e nitration of cellulose by a mixture of nitric and sulphuric acids results in a nitrocellulose containing about one per cent of sulphate. T h e sulphate content depends on the composition of the mixed acids and on other factors. In spite of considerable experimentation, there is some doubt about the form of the sulphate which is variously described a s mechanicalljr held ( 2 ) , inorganic (7), fixed sulphuric acid (4), or an acid ester and a neutral ester (5). T h e majority of workers have assumed the existence of some type of chemical bonding without providing direct evidence. Sheppard (8) estimated the sulphate content of unstabilized nitrocellulose by dissolving the ester in acetone and reprecipitating it with water. The acid liberated was titrated directly in the presence of the precipitate. T h e results obtained were said t o correspond t o the acidity extracted with dilute sodium bicarbonate solution. The present work was suggested by an argument advanced by ChCdin and Tribot (2) t o the effect t h a t the removal of sulphuric acid b y solution in acetone and reprecipitation in water supports the idea t h a t the acid is mechanically held. T h e inference appears t o be based on the assumption t h a t sulphate cleavage in acetone is not the likely reaction of a cellulose mixed ester containing sulphate groups. There is however considerable evidence t o show t h a t the rate of solvolysis of the sulphate ester of a cellulose mixed ester depends on several factors of which the liquid medium appears to be the most important. The solvolysis of both the sulphate ester and the acetate ester in acetic acid is well known (6). Cleavage of the acetate ester in water is more rapid than decomposition of the sulphate ester (3). 'Manuscript

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Section: Methodsmentioning

confidence: 99%

Hydrolysis of Cellulose Acetate Sulphate in Acetone

Keirstead¹,

Myers²

1954

Can. J. Chem.

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“…Tn a trial t o trace the contamination of the nitrates of the whole starch and dextrins, prepared with mixed acids (procetlurc '.c"), with sulphuric acid impurities5) the total sulphate content has now been determined (16). In this conncetion, it should be noted t,hat though different rnet,hods have been reported in thc literature for the det'erminat'ion of sulphuric acid and/or sulphuric esters in cellulose nkrate (11 : 17; 18: 19, pp.…”

Section: Resultsmentioning

confidence: 99%

Further Studies on Stabilization of Polymeric Carbohydrate Nitrates. The Stability of Dextrin Nitrates

1967

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“…The sulphate acid ester content of cellulose acetate sulphate was estimated by ion exchange methods (5) and more recently by titration in acetone/water solution before and after hydrolysis (2). I n a previous paper (3), methods were described for the determination of the sulphate ester content of unstabilized cellulose nitrates.…”

Section: Introductionmentioning

confidence: 99%

Determination of Sulphate Acid Ester in Unstabilized Cellulose Nitrate by the Hydrolysis Method

Gagnon¹,

Keirstead²,

Newbold³

1958

Can. J. Chem.

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The method of deter~uining sulphate acid ester in unstabilized cellulose nitrates by hydrolysis in acetone/water solution was evaluated. The precision of duplicate determinations for cotton and wood cellulose nitrates containing about 100% sulphate ester was -0.1 to +5.9% and +0.4 to +9.2%, respectively. With cellulose nitrates containing 69-43% and 69-47% sulphate ester, i t was +1.8 to +13.4% and +0.4 t o +21.0%. The sulphate acid ester content of both unstabilized cotton and wood cellulose nitrates increased with decreasing nitrogen content.

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A Study of the Sulphate Ester of Unstabilized Cellulose Acetate

Cited by 9 publications

References 0 publications

Hydrolysis of Cellulose Acetate Sulphate in Acetone

Hydrolysis of Cellulose Acetate Sulphate in Acetone

Further Studies on Stabilization of Polymeric Carbohydrate Nitrates. The Stability of Dextrin Nitrates

Determination of Sulphate Acid Ester in Unstabilized Cellulose Nitrate by the Hydrolysis Method

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