Organic compounds -- part of the class 532-570 series – Organic compounds – Percarboxylic acids or salts thereof
Patent
1994-05-13
1996-02-06
Dees, Jose G.
Organic compounds -- part of the class 532-570 series
Organic compounds
Percarboxylic acids or salts thereof
562 2, C07C179133
Patent
active
054897068
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/GB92/02087 filed Nov. 11, 1992.
The present invention relates to stabilised peracid solutions and their production.
Soluble peracids have a number of attractive properties, including oxidative and broad spectrum biocidal properties. As a consequence, they have been employed or proposed for use as oxidising agents in chemical synthesis reactions, as bleaching agents in the bleaching or cleansing of laundry and other substrates and as disinfectants or sterilisers for especially liquid media or solid surfaces.
One peracid which is widely available and suitable for the above-mentioned uses is peracetic acid which is usually produced in an aqueous solution by reaction between acetic acid and hydrogen peroxide, optionally in the presence of a catalyst such as a strong acid, including sulphuric, phosphoric and/or phosphonic acids. In a number of commercially available peracetic acid-containing compositions, the peracetic acid is present in equilibrium with the two reactants from which it is produced and water. Although such compositions may be used immediately after their production, they are often stored for considerable periods during their distribution and/or by the end user. During storage there is a tendency for some decomposition of the peroxygen species to occur, thereby progressively impairing the effectiveness of the composition for its desired purpose or requiring the use of an increased amount to attain a desired concentration of active ingredient. Plainly, therefore, it is desirable to find ways of improving the stability of peracid compositions, by which is meant ways of ameliorating or inhibiting the rate at which the measured concentration of peroxygen compounds and particularly peracetic acid falls during storage. One method of apparently improving the peracid stability in peracid compositions is described by Henkel in British Patent Specification no 1 580 561, which comprises employing a higher concentration of hydrogen peroxide relative to the peracetic acid than an equilibrium concentration. Essentially the same concept is disclosed in European Patent 0 024 125 to L'Air Liquide, but augmented by simultaneously diluting the acid catalyst below a minimal level so as to retard the rate of re-equilibration of the composition. By using excess hydrogen peroxide inventors seek to balance peracetic acid generation arising from slow re-equilibration against its rate of decomposition. Disadvantageously, the use of a considerable excess of one of the reagents inevitably increases the cost of the final product.
An alternative method of improving the storage stability of peracetic acid solutions has been proposed in European Patent 0 147 207 to Albright & Wilson, namely the incorporation of certain C6-C18 alkyl substituted benzene sulphonate wetting agents. In the course of the present investigations, it has been found that certain other wetting agents can be even more effective than alkyl benzene sulphonates at stabilising peracetic acid solutions.
According to one aspect of the present invention, there is provided a process for improving the storage stability of peracetic acid in a solution containing a wetting agent characterised by introducing therein an effective concentration of an aliphatic alcohol ethoxylate wetting agent which has an EO number of greater than 4.
According to a second aspect of the invention, there are provided peracetic acid solutions having improved storage stability by introduction therein of an effective concentration of an aliphatic alcohol ethoxylate wetting agent which has an EO number of greater than 4.
Advantageously, it has been found that the introduction of the specified wetting agent improves the retention of the important constituent, namely the peracetic acid in solution relative to like compositions containing no wetting agent or an alkyl benzene sulphonate, though it may not improve the retention overall of peroxygen species in the solution during storage. In general, peracetic acid solutions are stored at ambient temperature, which
REFERENCES:
patent: 4743447 (1988-05-01), Le Rouzic et al.
Barts Samuel
Dees Jos,e G.
Solvay Interox Limited
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