Characteristics of Nitrate Esters

The following Add ft Pjsfs are of limited distribution 1) G.A. Yanyecic, Decomposition Characteristics of Nitrate Ester Monopropellants , Rept No TM-705. 9161-03, Contract NOW-65-0123, Penn State Univ, Univ Park (1968) 2) R.K. Lund, Encapsulated Liquid... 

Since it was first synthesized in 1847 [2], nitroglycerin as a main component in liquid explosives, has been tremendously investigated and widely used in mining and other industrial blasting, as well as in military, such as propellant powers. Later, a series of liquid explosives of nitrate ester, such as dinitrate esters, with better explosive property and safety were developed [3-5]. In recent years, the United States has launched studies of high power and low characteristic signal propellants to continuously expand the application range of liquid nitrate esters [6]. 

Besides the UV spectroscopy of nitrate esters [20], researchers [21] have studied infrared absorption characteristics of a series of nitrate esters from methyl nitrate to n-butyl nitrate. Raman spectroscopy of nitrate esters and nitro compounds of aliphatic or aromatic nitrate has been investigated [22]. 

Some work [5] has been performed on the photochemical reaction between sulfur dioxide and hydrocarbons, both paraffins and olefins. In all cases, mists were found, and these mists settled out in the reaction vessels as oils with the characteristics of sulfuric acids. Because of the small amounts of materials formed, great problems arise in elucidating particular steps. When NO and 02 are added to this system, the situation is most complex. Bulfalini [3] sums up the status in this way The aerosol formed from mixtures of the lower hydrocarbons with NO and S02 is predominantly sulfuric acid, whereas the higher olefin hydrocarbons appear to produce carbonaceous aerosols also, possibly organic acids, sulfonic or sulfuric acids, nitrate-esters, etc. ... 

Interest has focused on derivatives of mannitol hexanitrate (14) as potential explosives because although this nitrate ester is a powerful explosive it has some property characteristics of a primary explosive. Treatment of mannitol hexanitrate (14) with pyridine or ammonium carbonate " in aqueous acetone leads to a very selective denitration with the formation of mannitol-1,2,3,5,6-pentanitrate (77). Marans and co-workers synthesized the acetate (78), the propionate (79), and the phenylacetate (80) derivatives of mannitol-1,2,3,5,6-pentanitrate and all have significantly lower melting points than mannitol hexanitrate. The incorporation of such groups can also help to increase the solubility of an explosive in the melt of another explosive. 

Typical crystalline materials used as oxidizers are perchlorates, nitrates, nitro compounds, nitramines, and metal azides. The polymeric materials used as fuel components are divided into nitrate esters, inert polymers, and azide polymers. Optimized combinations of these oxidizer and fuel components yield the desired ballistic characteristics of propellants or explosives. 

In later years much important work was carried out in the St. Andrews laboratories on anhydro-sugars and their derivatives (G. J. Robertson) and on the nitrate esters of methylated sugars (J. W. H. Oldham). Irvine never diminished his keen interest in this work but it was inevitable that less time could be devoted to chemical research after he had assumed the onerous duties of Principal and Vice-Chancellor in 1921. It was characteristic of him, however, that only a few days before his death he was busy propounding long-term schemes of research on possible developments of sugar derivatives for use in chemotherapy. 

With these compounds the presence of the halogen will have been detected in the tests for elements. Most acid halides undergo ready hydrolysis with water to give an acidic solution and the halide ion produced may be detected and confirmed with silver nitrate solution. The characteristic carbonyl adsorption at about 1800 cm -1 in the infrared spectrum will be apparent. Acid chlorides may be converted into esters as a confirmatory test to 1 ml of absolute ethanol in a dry test tube add 1 ml of the acid chloride dropwise (use a dropper pipette keep the mixture cool and note whether any hydrogen chloride gas is evolved). Pour into 2 ml of saturated salt solution and observe the formation of an upper layer of ester note the odour of the ester. Acid chlorides are normally characterised by direct conversion into carboxylic acid derivatives (e.g. substituted amides) or into the carboxylic acid if the latter is a solid (see Section 9.6.16, p. 1265). 

The propellants derived from nitrate ester-based binders possessed the undesirable characteristics associated with nitrate ester groups such as thermal instability, hydrolytic instability, and impact instability (especially for highly nitrated compositions). For this reason a study was undertaken to prepare polymeric binders in which oxygen is carried in the form of the more thermally and hydrolytically stable nitro group. Aerojet General Corp., working with both the Purdue and the Ohio Research Foundations, carried out the bulk of these studies. The following are typical of the condensation monomers synthesized by Aerojet ... 

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