| 摘要 |
Nitroform is separated from reaction mixtures containing concentrated nitric acid by adding to the mixture an amount of water sufficient to reduce and subsequently maintain the content of nitric acid present therein below 68 per cent, and then submitting the diluted mixture to distillation whereby nitroform, together with water, is obtained as distillate. In a preferred embodiment, some of the nitric acid is distilled off from the initial mixture before water is added. If the distillation is carried out under partial vacuum, the concentration of NHO3 must be maintained below about 66.5 per cent. In an example, a reaction mixture, obtained by nitration of acetylene, contained nitroform (10.5 per cent), nitric acid (75 per cent) and water (12.5 per cent). About half of the nitric acid was distilled off through a column under a pressure of 200 mm., giving a residue containing 18 per cent nitroform, 56 per cent nitric acid and 23 per cent water. The contents of the still were diluted with water to make the composition 14.5 per cent nitroform, 46.5 per cent nitric acid and 39 per cent water, and the diluted mixture was distilled using the column at a pressure of 150 mm. to give an aqueous distillate, containing 47 per nitroform, which separated in two phases. The lower layer was 90 per cent nitroform.
|
