Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1998-11-24
1999-11-30
Shah, Mukund J.
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
544 36, 544 38, C07D27920, C07B 4504
Patent
active
059945389
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to novel spherical agglomerates of 10-phenothiazinylpropanoic acid. The invention also relates to a process for obtaining those agglomerates.
10-phenothiazinylpropanoic acid is an organic product used as an intermediate in synthesis.
It is represented by the following formula ##STR1##
A method for preparing that product is described by Nathan L., Smith J. in Org. Chem 15, 1125 (1950).
The product obtained is in the form of a precipitate which is difficult to separate by filtering, which necessitates re-crystallisation from an organic solvent, generally an alcohol.
Further, in many applications, the products used must be in a form in which they must satisfy a number of requirements: which generate dust; temporary hopper type storage units or during use in a subsequent transformation process, or during long term storage in the usual packaging.
In order to satisfy the above requirements, the present invention provides a novel presentation of 10-phenothiazinylpropanoic acid and a process for obtaining it which can overcome the filtering problem.
More precisely, the present invention provides spherical agglomerates of 10-phenothiazinylpropanoic acid.
In the description of the present invention, the term "10-phenothiazinylpropanoic acid" includes 3-(10-phenothiazinyl)propanoic acid and similar products, i.e., products in which the benzene rings of the phenothiazinyl radical carry substituents provided that they do not modify the surface properties. Examples which can be cited are low alkyls (C.sub.1 -C.sub.4), halogen atoms or a CF.sub.3 radical.
The term "spherical" agglomerates means solid particles with a high degree of sphericity.
The process for preparing the spherical agglomerates of 10-phenothiazinylpropanoic acid is characterized by stirring a suspension of 10-phenothiazinylpropanoic acid in water in the presence of a liquid binder which is not miscible with water selected from esters of aliphatic or cycloaliphatic acids, aliphatic or cycloaliphatic alcohols, and aliphatic or cycloaliphatic ketones.
The agglomerates obtained in accordance with the invention have physicochemical properties which are peculiar to them. The essentially spherical particles have a diameter which can vary within a wide range. Size determination is carried out using image analysis.
Generally the particle size, expressed as the medial diameter (d.sub.50), is from 50 .mu.m to 3000 .mu.m, preferably from 200 .mu.m to 1200 .mu.m and more preferably between 500 .mu.m and 1000 .mu.m. The medial diameter is defined as that at which 50% by weight of the particles have a diameter larger or smaller than the medial diameter.
FIG. 1 shows a photograph of the agglomerates of the invention taken using a microscope (magnification=16) which shows the spherical shape of the particles obtained.
A further characteristic of the agglomerates of the invention is that the fines ratio (particles of less than 100 .mu.m) is low, preferably less than 0.5%, more preferably less than 0.1%.
In accordance with the process of the invention, spherical agglomerates of 10-phenothiazinylpropanoic acid are prepared by stirring a suspension of 10-phenothiazinylpropanoic acid in water in the presence of a liquid binder which is not miscible with water as defined above.
When selecting the liquid binder, an organic solvent is used in which the 10-phenothiazinylpropanoic acid is very slightly soluble, i.e., with a solubility of less than 5%, preferably less than 1%.
The liquid binder, selected from esters of aliphatic or cycloaliphatic acids, aliphatic or cycloaliphatic alcohols, and aliphatic or cycloaliphatic ketones, generally satisfies this requirement when its carbon condensation is at least 5. There is no upper limit to the number of carbon atoms provided that the binder remains liquid during granulation.
Thus in a variation of the process of the invention, a liquid which may be solid at ambient temperature (usually between 15.degree. C. and 25.degree. C.) but fusible under the granulation temperature conditions, is used. In this case
REFERENCES:
patent: 3160630 (1964-12-01), Vierling
patent: 3555156 (1971-01-01), Kviesitis et al.
Journal of Heterocyclic Chemistry, vol. 9, No. 2, Apr. 1972, pp. 325-330, XP002017108, Sister M.C. Malmstrom et al, "The crystal and molecular structure of phenothiazine-10-propionic acid".
Journal of Organic Chemistry, vol. 15, No. 5, Sep. 1950, Easton US, pp. 1125-1130, XP002017100 N.L. Smith: "Synthesis of phenothiazine derivatives for use as antioxidants".
Carencotte Frederic
Marchal Philippe
Savet Jean-Claude
Rhodia Chimie
Shah Mukund J.
Sripada Pavanaram K
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