Esters of starch

Nitrostarch (NS) is a nitrate ester (more properly a mixt of several nitrate esters) of starch, which is a plant-product polysaccharide of the general formula (CgHujOj) The general molecular formula for NS is [C6H7(OH)x-(0NO2)y]n where x + y - 3, The following empirical relation, similar to that used for NC... 

The problem of how to stabilize nitrostarch has been solved by different means, but the majority of stabilization processes remain obscure as patent secrets. None the less, from certain observation some general conclusions can be made. It was early observed by Bechamp [13] that nitrostarch obtained by nitration in nitric acid alone is more stable than one obtained by means of nitric acid mixed with sulphuric acid. This has been confirmed experimentally by Hackel and T. Urbanski [18], and seems likely to be explained by the formation of starch sulphates or mixed nitric and sulphuric esters of starch. 

On the other hand various polymeric derivatives of 4-aminosalicylic acid show no activity. They are not active either in the form of the poly(N-acryloyl-4-amino-salicylic acid) (83) or in the form of the acetylsalicylic ester of starch (84). Due to their mechanism of action, that is the interference in the bacterial metabolism, 4-amino salicylic acid and sulfamide derivatives can be active only in the free form. 

Composition Nitric ester of starch. It is not a definite, single compound, but rather a mixture of various esters of different degrees of nitration, measured by the percentage of nitrogen. Like nitrocellulose, nitrostarch is a nitrate and not a nitro compound and the correct chemical name is starch nitrate. However, the term nitrostarch has been generally adopted. 

SAFETY PROFILE A very dangerous fire and explosion hazard when exposed to heat, flame, shock, or oxidizers. It is a powerful high explosive. Nitrostarch is not a definite compound, but a mixture of various nitric acid esters of starch with different degrees of nitration. When heated to decomposition it emits toxic fumes of NOx. See also NITRO COMPOUNDS. 

V. Preparation and Properties of Other Organic Esters of Starch. 300... 

VI. Preparation and ProF>erties of Inorganic Esters of Starch. 303... 

Starch acetates have been extensively investigated both as to manner of preparation and as to properties. This is in contrast to the other organic esters of starch of which only a few have been prepared, and, of these, only a few characterized. Among the inorganic esters, the starch nitrates have received the most attention and have risen to industrial importance because of their use in explosives. Partly because of this use and the secrecy attending their manufacture, a full disclosure of the preparation and properties of starch nitrates has not been published. 

Higher aliphatic esters of starch are generally prepared by treating starch with the acid chloride in the presence of alkali or a tertiary organic base " such as pyridine, " quinoline, picoline," or dimethylani-... 

Nitric acid esters of starch are the oldest known starch derivatives and are the only starch esters commercially produced on a large scale. Like cellulose nitrates, the starch nitrates are excellent explosives. They are used extensively in blasting compositions, for quarrying and for certain types of mining. Tapioca starch was used mainly for commercial nitrations in the United States until the advent of World War II and the disruption of supplies made it necessary to nitrate com starch. This transition has been accomplished with little difficulty, although the exact process used is a trade secret. 

Chlorinated and/or oxidized starches crosslinked with glyoxal were used to produce a high-strength size for paper.573 Coating adhesives were also prepared by crosslinking glycidyl esters.1385 In addition, esters of starch with inorganic acids (such as starch phosphates) were crosslinked with various aliphatic and aromatic aldehydes in the presence of urea, melamine and similar compounds.1322... 

Pyroxylin Starch nitrate UN0146 UN1337. A nitric ester of starch, probably the octonitrate used for blasting explosives, either alone, or by mixing 10% of it with a mixture of sodium nitrate and carbonaceous material. See pyroxylin [9004-70-0]. 

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