Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1990-10-15
1992-06-02
Springer, David B.
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
562433, 562445, 562554, 562570, C07D20920, C07C22942
Patent
active
051188155
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE ART
The present invention relates to a method for purification of amino acid, particularly to a method for crystallization of amino acid, more particularly to a method for improving crystal shape by crystallization operation of amino acid.
BACKGROUND ART
As conventional methods for crystallization of amino acid, there have been proposed a method for crystallization which comprises concentrating an aqueous solution of amino acid under reduced pressure, a method which comprises neutralization for crystallization, a method which comprises crystallization with a solvent while adding a lower alcohol or a ketone to the aqueous solution in large quantities, and so on (cf. Japanese Patent Application Laid-Open Nos. 59-39857, 59-45898, etc.).
Among these methods, in the method for crystallization which comprises concentration under reduced pressure, fine amino acid crystals precipitated tend to take bubbles in the crystals and cause bumping so that care must be required for the concentrating operation. Furthermore, according to the method which comprises neutralization for crystallization, crystals tend to float on the upper layer of the solution and the crystals do not grow as expected and in most cases, therefore, it might take time for solid-liquid separation. On the other hand, the method which comprises crystallization of amino acid by adding a lower alcohol or a ketone requires separate equipments for recovering the organic solvent, which not only leads to complicated process but is also economically disadvantageous, because it is impossible to completely recover the solvent.
Accordingly, it is significant in the art to provide a method for crystallization of amino acid having a high purity, in a simple manner using simple apparatuses.
DISCLOSURE OF THE INVENTION
The present invention relates to a method for crystallization of amino acid characterized by allowing a surfactant and/or an alcohol in an amino acid solution, upon crystallization of the amino acid.
MODE FOR PRACTICING THE INVENTION
The amino acid which is crystallized in the present invention is not particularly limited but preferred examples include phenylalanine, tryptophan, serine, isoleucine, valine, threonine and leucine. It is not particularly limited as how to prepare these amino acids but the amino acids may be any one prepared by fermentation, chemical synthesis, enzymatic method and other processes. In general, the present invention is applied to crystallization of L-amino acid but may also be applicable to D- or DL-amino acid and to amino acid derivatives.
The surfactant and alcohol which can be used in the present invention are as follows.
As anionic surfactants, there are effectively used fatty acid salt type, sulfate salt type, alkylallylsulfonate type and phosphate salt type. Specific examples include sodium oleate, sodium lauryl sulfate, sodium dodecylbenzenesulfonate, lecithin, etc.
As cationic surfactants, there are effectively used quaternary ammonium salt type, aliphatic amine type and pyridinium type. Specific examples include SANISOL (manufactured by Kao Atlas Co., Ltd.), laurylamine, lauryl hydrogensulfate pyridinium, etc.
As nonionic surfactants, there are effectively used polyoxyethylene ether type, sorbitan alkyl ester type, esters of polyvalent alcohols and fatty acids and fatty acid ethanolamide type. Specific examples include Brij (manufactured by Atlas Co., Ltd.), Tween (manufactured by Atlas Co., Ltd.), glycerol monostearate, etc.
As alcohols, polyvalent alcohols are effective. Specific examples include ethylene glycol, propylene glycol, etc.
Upon practice of the present invention, the additive described above is dissolved in an acid or alkali solution of amino acid and then adding an alkali or acid to the solution to effect crystallization by neutralization. Alternatively, after the additive described above is dissolved in an amino acid aqueous solution, the aqueous solution is concentrated to crystalize amino acid. In this case, however, since some of the additive is foaming, it is recommended
REFERENCES:
patent: 4675339 (1987-06-01), Inoue et al.
Saeki Masura
Shiroshita Yoshinari
Toyomasu Ryuta
Ajinomoto Co. Inc.
Springer David B.
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