Methylenediamines synthesis

Butadiene is by far the most important monomer for synthetic rubber production. It can be polymerized to polybutadiene or copolymerized with styrene to styrene-butadiene rubber (SBR). Butadiene is an important intermediate for the synthesis of many chemicals such as hexa-methylenediamine and adipic acid. Both are monomers for producing nylon. Chloroprene is another butadiene derivative for the synthesis of neoprene rubber. 

Chapman studied the nitrolysis of symmetrical methylenediamines. The nitrolysis of N, N, N, M-tetramethylmethylenediamine with nitric acid-acetic anhydride-ammonium nitrate mixtures gives both dimethylnitramine and RDX the latter probably arises from the nitroT ysis of hexamine formed from the reaction of ammonium nitrate and formaldehyde released from the hydrolysis of the methylenediamine. The same reaction with some morpholine-based methylenediamines (105) allows the synthesis of l,3,5-trinitro-l,3,5-triazacycloalkanes (106). 

In addition to the Ross-Schiessler process, utiliang P-CH2O and AN, the synthesis of RDX/ HMX mixts has also been reported starting with other small molecules (Ref 7), namely, methyl-amine nitrate methylenediamine dinitrate and nitramine (NH2NO2) in combination with CH2O. In these reactions, the intermediate formation of Hexamine or a cyclic analog, is not necessarily established... 

Of the numerous methods reported by Bdhme et al. for the synthesis of preformed iminium salts, the most general and convenient involves cleavage of methylenediamines (23) by acyl halides (24) or alkyl chlorocarbonates (25), providing preformed iminium salts (26) in quantitative yield and in near analytical purity (equation 4). The by-product of these reactions, a dialkylamide (27) or a dialkylurethane (28), is easily removed since it remains in solution during precipitation of the iminium salt. The ionic nature of iminium salts produced by this method is well established, although an equilibrium between the... 

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