Derivatives of polynitroaliphatic alcohols

Polynitroaliphatic alcohols containing nitro groups on the carbon fi to the hydroxy functionality are less basic than their alkyl counterparts. This decreased basicity of the hydroxy group makes reactions such as esterification, acetal formation and alkylation much slower than usual, and in some cases, these reactions may not proceed without catalysts. To add to the problem, normal base catalysts cannot be used in conjunction with 2,2-dinitroalkanols and l,l,l-trinitro-2-alkanols because of their facile dissociation in alkaline solution. 

The weak nucleophilic nature of polynitroaliphatic alcohols means that reactions often need to be catalyzed by Brpnsted acids or Lewis acids. The following methods are commonly used for the esterification of polynitroaliphatic alcohols (1) heating a solution of the alcohol and acid in the presence of sulfuric acid with Dean-Stark removal of water ° (2) using the acid chloride or anhydride in the presence of aluminium chloride (3) reacting the acid and alcohol 

A huge number of ester and carbonate derivatives of polynitroaliphatic alcohol have been synthesized driven by the search for new explosives and energetic plasticizers and oxidizers for propellant and explosive formulations. Most of these are derived from 2-fluoro-2,2-dinitroethanol and 2,2,2-trinitroethanol ° and have excellent oxygen balances. Some examples are illustrated above (168-174) but more comprehensive lists can be found in numerous reviews. Direct esterification of polynitroaliphatic alcohols with nitric acid, mixed acid, or acetic anhydride-nitric acid has been used as a route to mixed polynitroaliphatic-nitrate ester explosives.  

Formals and acetals prepared from the reaction of polynitroaliphatic alcohols with formaldehyde and acetaldehyde have found use as explosive plastisizers for nitrocellulose and in plastic bonded explosives (PBXs). Formals of polynitroaliphatic alcohols are commonly prepared via reaction with trioxane or paraformaldehyde in the presence of sulfuric acid as a condensing agent. Bis(2,2-dinitropropyl)formal (175) is prepared from the reaction of trioxane with 2,2-dinitropropanol (25). The reaction of 2,2,2-trinitroethanol (159) and 2,2-dinitro-l,3-propanediol (19) with formaldehyde in the presence of sulfu- 

Sulfuric acid cannot be used for the synthesis of acetals and so bis(2,2-dinitropropyl)acetal (179) is prepared from the reaction of paraldehyde with 2,2-dinitropropanol (25) in the presence of boron trifluoride.333 323 50 50 eutectic mixture of bis(2,2-dinitropropyl)formal (175) and bis(2,2-dinitropropyl)acetal (179) has found use as an energetic liquid plastisizer for nitrocellulose. 

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