Trinitro derivatives of naphthalene

There are three isomers of trinitronaphthalene known, which can be obtained by direct nitration of a-nitronaphthalene, viz. the a- (1,3,5-), p- (1,3,8-), and y-(1,4,8-) or 1,4,5-isomers. The 5- isomer (1,2,5-) does not exist, according to Dimroth and Ruck [18a]. It is probably a mixture of the isomers. 

They are very fine crystalline, light brownish-grey products, sparingly soluble in organic solvents. 

The crude product of the nitration of naphthalene or a- nitro- or commercial dinitro-naphthalene is a mixture of the four isomers. It melts at 115-160°C, the melting point depending on the nitration conditions. 

Separation of the isomers can be achieved by taking advantage of their different solubility in alcohol. Thus, the 1,3,5-isomer dissolves in alcohol only with great difficulty. The 1,4,8-isomer does not dissolve in 70% alcohol, while the 1,3,8-isomer dissolves in the hot solution and may be precipitated from the solution either by cooling or by dilution (Pascal and Gamier [33]). 

The conversion of dinitro- into trinitro-naphthalene may be achieved by using nitrating mixtures of varying compositions  

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Trinitro derivatives of naphthalene Chemical properties Structure of a- and -y-isomers a-Triniironaphihalcnc y-Trinitronaphihalcnc Tetranitro derivatives of naphthalene Structure of teiraniironaphthalcnes Thcrmochcmical properties of nitro naphihalencs Side reactions of the nitration of naphthalene Manufacture of nitro derivatives of naphthalene Nitration of naphthalene to mononitronapchalcnc German method Separation... 

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