Organic compounds -- part of the class 532-570 series – Organic compounds – Percarboxylic acids or salts thereof
Patent
1991-11-20
1993-06-15
Killos, Paul J.
Organic compounds -- part of the class 532-570 series
Organic compounds
Percarboxylic acids or salts thereof
562 2, C07C40700, C07C40900
Patent
active
052200523
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a process for the manufacture of organic peroxyacids, and more particularly to organic peroxyacids having poor solubility in aqueous media.
The detergents industry constantly seeks to improve the cleansing performance of its compositions, and in a effort to do so under low temperature washing conditions has investigated the incorporation of quite small amounts of peroxyacids. Most of the peroxyacids contemplated have been organic peroxycarboxylic acid compounds containing at least 7 carbon atoms and many of them have exhibited poor solubility in aqueous media, a feature usually shared with the corresponding carboxylic acid from which they are or could be derived.
There have been many different processes proposed for the manufacture of organic peroxyacids, including the poorly soluble ones. A number have used sulphuric acid as a main constituent of the reaction mixture. Parker et al in JACS 77:4037-41 and/or JACS 79:1929-32 suggested the drop-wise addition of concentrated hydrogen peroxide to a sulphuric acid solution of a long chain aliphatic mono or di-carboxylic acid. Hutchins, in U.S. Pat. No. 4,119,660, discloses in column 1 that there are a number of problems with the Parker process, such as rate of peracid formation and/or small particle size of peracid product and accordingly, he suggests an alternative procedure in which the hydrogen peroxide and sulphuric acid reagents are premixed, and the solid carboxylic acid is subsequently introduced therein. Hutchins asserts that the acidity of his reaction mixture is of crucial importance, being at least 69% sulphuric acid in order to attain an unexpected decrease in reaction time, compared even with an acidity of 66.5%. Virtually the same procedure had been proposed nearly 20 years earlier by Krimm in U.S. Pat. No. 2,813,896, the difference being that the exemplified amounts of sulphuric acid were numerically lower than the range identified by Hutchins. Camden in U.S. Pat. No. 4,233,235 discloses a continuous process for making similar long chain aliphatic peroxyacids and asserts in column 4 that batch processes, presumably for the same products, exhibit more safety problems and produce smaller crystals. In his process, he employs balanced continuous addition of reagents to and continuous withdrawal of product a constant residence time of his reagents in the reaction mixture. Bettle in U.S. Pat. No. 4,314,949 discloses that in a preferred method of making aliphatic percarboxylic acids, particulate carboxylic acid is added to a peroxide/sulphuric acid mixture. Hutchins in a second patent, U.S. Pat. No. 4,244,884, discloses a variation to the Camden continuous process, in which he recycles mother liquor separated from the product. It will be observed that in column 3, he asserts that the carboxylic acid added to the reaction mixture typically precipitates in situ, so that most of it is in the solid form. He also indicates that the inherent reaction between carboxylic acids and hydrogen peroxide can present safety problems, since it can become uncontrollable if it is not carefully controlled.
Peroxyacids are often needed in smaller quantities than justify the capital outlay inherent in a continuously operated process. Consequently, it would be desirable to devise a batch process variation that can be readily carried out so as to avoid the formation of hazardous compositions during the entire process. In the course of investigations which have lead to the instant invention, the inventors have found that there are a number of different factors which must be balanced in order to retain a viable and safe process.
A wide range of compositions containing relatively high concentrations of hydrogen peroxide and organic material, such as carboxylic acids are conventionally viewed as hazardous on account of their tendency to decompose spontaneously. Thus, too much hydrogen peroxide in solution causes safety problems. Since the solubility of the carboxylic acid is usually rather low, it means that peroxide concentration must be kept low
REFERENCES:
patent: 2813896 (1957-11-01), Krim
patent: 4119660 (1978-10-01), Hutchins
patent: 4233235 (1980-11-01), Camden et al.
patent: 4244884 (1981-01-01), Hutchins et al.
patent: 4314949 (1982-02-01), Bettle, III et al.
J. Amer. Chem. Soc., 1955, vol. 77, pp. 4037-4041, Parker, et al., "Peroxides. II. Preparation, Characterization and Polarographic Behavior of Long-Chain Aliphatic Peracids".
J. Amer. Chem. Soc., 1957, vol. 79, pp. 1929-1931, Parker, et al., "Peroxides. IV. Aliphatic Diperacids".
Carr Graham
James Alun P.
Troughton Nicholas A.
Willson Andrew J.
Interox Chemicals Limited
Killos Paul J.
Nazario Porfirio
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