Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Patent
1994-02-17
1995-05-16
Reamer, James H.
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C07C 4545
Patent
active
054162394
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a process for the production of fatty ketones by pyrolysis of fatty acid magnesium salts.
2. Statement of Related Art
Long-chain symmetric and asymmetric ketones based on fatty acids, so-called "fatty ketones" are used either directly or after sulfonation or quaternization as additives for fabric softeners, hair shampoos, corrosion inhibitors or flotation aids (Chem. Ing.-Tech. 62, 416 and 512 (1990).
The production of fatty ketones by pyrolysis of fatty acid salts in the presence of catalytic quantities of calcium, iron or manganese salts has been known since 1855 and is covered by extensive literature (Houben-Weyl, Methoden der Organischen Chemie, Thieme-Verlag, Stuttgart, Vol. 7/2a, pages 622 et seq.).
Recently, magnesium oxide has been successfully used as the catalyst. Thus, a laboratory process for the production of stearone, in which 1 mole of stearic acid and 0.5 mole of magnesium oxide are reacted at 340.degree. C., is described, for example, in Org. Synth., Vol. 33, pages 854 et seq. For working up, the crude product has first to be washed with sulfuric acid, water and sodium hydrogen carbonate solution, the pure stearone only being obtained after two crystallizations. In addition, it is recommended that foam formed during the reaction be either mechanically destroyed or controlled by antifoam agents. In overall terms, a process such as this is unsuitable for industrial application on account of the high outlay on equipment for working up.
A process for the production of fatty ketones by pyrolysis of magnesium salts of fatty acids is also known from J. Soc. Chem. Ind. 66, 402 (1947). To solve the foam problems, it is proposed in this reference initially to introduce the fatty acid in far less than the equivalent quantity relative to the magnesium oxide, to heat the reaction mixture and then continuously to introduce the remaining fatty acid. Although foam problems can be minimized in this way, they cannot be eliminated altogether so that part of the fatty acid is still discharged and is thus lost in the absence of additional measures. Another disadvantage of the process is that the magnesium salt has to be separated by filtration, sedimentation or treatment with mineral acids after the reaction and, accordingly, cannot be quantitatively removed from the products.
Accordingly, the problem addressed by the present invention was to provide a new process for the production of fatty ketones which would not have any of the disadvantages described above.
DESCRIPTION OF THE INVENTION
The present invention relates to a process for the production of fatty ketones by pyrolysis of fatty acid magnesium salts, characterized in that fatty acids corresponding to formula (I): atoms and 0, 1, 2 or 3 double bonds, are heated to temperatures of 320.degree. to 360.degree. C. in the presence of magnesium oxide and the fatty ketones formed are distilled off from the reaction mixture under reduced pressure.
Although the production of fatty ketones by pyrolysis of fatty acid magnesium salts has been known for some time, it has only now surprisingly been found that the foaming and associated problems can be suppressed in the production process if the fatty ketones are distilled off from the reaction mixture under reduced pressure at the reaction temperature. In this way, losses of starting material are avoided and products with only a minimal magnesium content in relation to the prior art are obtained. By virtue of the fact that the fatty ketones have only a short residence time in the hot reaction zone as a result of distillation, so that they are not seriously exposed to high temperatures, light-colored products are surprisingly obtained, the chromophoric groups remaining in the bottom product of the distillation process. The present invention also includes the observation that the bottom product accumulating during the reaction can be directly reacted with fatty acid again so that the process can be carried out semi-continuously. Furthe
REFERENCES:
patent: 3391191 (1968-07-01), Velde
patent: 5001273 (1991-03-01), Kleine-Homann
Org. Synth., vol. 33, S.854 ff.
J. Soc.Chem. Ind. 66, 402 (1947).
Chem. Ing.-Tech. 62, 416 u. 512 (1990).
Houben-Weyl, Methoden der Organischen Chemie, Thieme-Verlag, Stuttgart, Bd. 7/2a, S.622 ff.
Baumann Horst
Breucker Christoph
Eierdanz Horst
Gutsche Bernhard
Jeromin Lutz
Henkel Kommanditgesellschaft auf Aktien
Jaeschke Wayne C.
Millson Jr. Henry E.
Reamer James H.
Szoke Ernest G.
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