Patent GB-613853-A (GB)
Title: Improvements in and relating to the production of organic nitro compounds
IPC: C07C205/03
Filed: 1946-01-14
Abstract: Dinitro compounds, nitro alcohols and other oxy-nitrogen compounds are obtained by reacting an aliphatic, alicyclic or aliphaticalicyclic mono-olefine with nitrogen trioxide in the absence of oxygen and treating the product with water or an aliphatic mono-alcohol containing less than six carbon atoms, e.g. methanol or ethanol, to convert nitro-nitrites produced to nitro-alcohols.  The nitration is preferably conducted below 0 DEG  C. Most suitable olefines are the aliphatic hydrocarbons containing up to 8 carbon atoms and cyclohexene.  It is preferred to employ an inert solvent which in the case of the C3 to C6 aliphatic mono-olefines is an oxygen containing organic solvent selected from saturated aliphatic, saturated alicyclic or saturated aliphatic-alicyclic compounds containing carbon, hydrogen and oxygen only and having no oxygen containing groups other than ether or ester groups and no 3- or 4-membered rings, but excluding esters of formic acid; saturated heterocyclic or saturated aliphatic-heterocyclic compounds containing carbon, hydrogen and oxygen only and having only carbon and oxygen in the ring and no other groups except hydrogen, hydrocarbon, ether or ester groups, but excluding such compounds containing 3- or 4-membered rings.  Specified solvents of this type are alkyl monoethers, e.g. methylated ether, di-isopropyl, di-isoamyl-, di-n-propyl- and di-n-amyl-ethers; diethers, e.g. methylal; dioxan, tetrahydrofuran; esters of saturated aliphatic monocarboxylic acids, e.g. ethyl (propyl or amyl) acetate.  These solvents as well as other inert solvents, e.g. carbon tetrachloride, chloroform and benzene are also suitable for use with the other olefines.  The nitrogen trioxide may be in liquid or gaseous form and superatmospheric pressure may be employed. The dinitro compound may be separated before or after treatment of the nitration product with water or alcohol, e.g. by freezing out from an organic solvent such as methanol, ethanol, acetone, ether.  The nitro-nitroso compounds produced may be recovered by allowing the reaction mixture to stand when they separate in the dimeric form.  When an alcohol, e.g. methanol, is used for the hydrolysis, the solvent is distilled off after nitration and the product dropped into the alcohol, the dinitro compound (if a p  solid) is frozen out, the alcohol distilled off and the nitro alcohol recovered by treating the residue with an excess of water, extracting with a solvent, e.g. ethyl acetate, and then distilling, whilst the small amount of nitro-nitrate produced is recovered by fractional distillation of the non-aqueous layer under reduced pressure.  In examples: (1) nitrogen trioxide is added to isobutene in dry methylated ether at -5 DEG  C. the solvent is removed and the residue stirred with water, bis-(nitroso-nitro isobutane) and nitrotertiary butanol are recovered and the insoluble oil which remains is treated with alkali to convert the 1,2-dinitroisobutane into a -nitro-isobutene; (2) propylene is passed into nitrogen trioxide in dry methylated ether at -5 DEG  C. The solvent and excess oxides of nitrogen are removed and the residue stirred with water. Bis-(nitroso-nitro propane) and 1-nitro-propanol-2 are recovered and the insoluble oil which remains is distilled to yield 4-nitro-3-methyl-furazan oxide, 1,2-dinitropropane and a little nitropropylene.  Specifications 583,468 and 604,360 are referred to.