PEROXYACID MANUFACTURE

摘要

In one class of processes for making poorly soluble organic peroxyacids the corresponding carboxylic acid is reacted with hydrogen peroxide in a reaction medium containing a high concentration of sulphuric acid. The presence of such constituents in the reaction mixture and the manner of the reactants and the way in which they are brought into contact, can result in the processes being hazardous. In the present invention, hazard problems are reduced or eliminated by first dissolving the carboxylic acid in concentrated sulphuric acid, secondly forming a Caro's acid solution containing a complementary amount of sulphuric acid and hydrogen peroxide within a predetermined range, and then introducing the carboxylic acid solution at a controlled rate in the Caro's acid solution, often over a period of from about 30 to 90 minutes, with agitation and temperature control. The compositions of the two reactant solutions are precalculated relative to each other such that the A value (weight ratio of sulphuric acid to the combined weight of it and water) either increases during addition of the carboxylic acid solution or if the latter is relatively less insoluble, stays the same or increases. The solutions are preferably formulated to provide an A value at the end of the reaction period selected in the range of around 0.7 to around 0.8, at a temperature of around 20 to 45 DEG C, the more soluble tending towards the lower end of each range and the less soluble towards the upper end of each range. The process is especially suitable for making poorly soluble aliphatic mono or diperoxycarboxylic acids such as peroxynonanoic acid or diperoxydodecanedioic acid, or for aromatic group substituted peroxyacids in which the peroxydation occurs in a primarily aliphatic environment, such as phthalimidoperoxyhexanoic acid.