Process for preparing 1,4-butandiol monitrate

A process for the preparation of 4-nitrooxybutan-1-ol comprising:

• step a) reacting an excess of 1,4-butanediol with an acid of formula R—C(O)OH wherein R is a linear or branched (C3-C5)-alkyl chain in the presence of a acidic catalyst and in an aliphatic unpolar solvent, followed by selective separation of 1,4-butandiol monoester of formula (I)
• RC(O)O—(CH2)4—OH (I)
• wherein R is as above defined, from reaction mixture;
• step b) nitration of RC(O)O—(CH2)4—OH wherein R is as above defined, with a mixture of cone. H2SO4 and conc. HNO3, or a mixture of nitric acid and acetic acid or acetic anhydride, followed by isolation of the 4-nitrooxybutan-1-ol monoester of formula (II),
• RC(O)O—(CH2)4—ONO2 (II)
• wherein R is as above defined;
• step c) selective hydrolysis of the alkyl acid moiety of the compound (II) by an inorganic base, in a one layer system, followed by purification of the 4-nitrooxybutan-1-ol of formula (III)
• HO—(CH2)4—ONO2 (III);
• said process is characterized in that the nitration step is performed using the 1,4-butandiol monoester of formula (I) containing an amount of 1,4-butandiol below 1%.