Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1999-11-29
2000-12-05
Owens, Amelia
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C07D31300
Patent
active
061569100
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an .epsilon.-caprolactone which has excellent thermal-discoloration resistance properties and to a method of producing thereof. The present invention also relates to a polycaprolactone having low discolorability and which is obtained by using the .epsilon.-caprolactone, and to a method of producing thereof.
TECHNICAL BACKGROUND
A method consisting of oxidising cyclohexanone is typically known as a method of producing .epsilon.-caprolactone.
The method of oxidising the cyclohexanone is a method of cooxidation using aldehyde(s) or a method using organic peroxides as oxidising agent.
Peracetic acid, perpropionic acid, perisobutyric acid or the like are used as the organic peracids.
Acetaldehyde, benzaidehyde, alkyl-substituted benzaldehydes or the like are used as aldehydes for the co-oxidation.
The synthesised carboxylic acids may, for example, in case of aliphatic carboxylic acids be directly used as products for industrial use; in case of aromatic carboxylic acids, they can be transformed through a further oxidation into adipic acids or the like.
.epsilon.-caprolactone is polymerised and then used as a moulding material, for polyester polyols, for biodegradable plastics or the like. However, during polymer production, there is an influence on the polymerisation reaction, and there are risks of obtaining discoloured resins. This is due to the great influence of the impurities contained in the .epsilon.-caprolactone on the reaction rate and on the colour hue of the polymer. Particularly, the content of the small amount of impurities contained in the .epsilon.-caprolactone, the acid value thereof, the water content thereof or the like should be optionally reduced, since they have an influence on the polymerisation reaction-rate, on the value obtained at the thermal discoloration stability test (APHA) of the .epsilon.-caprolactone itself and on the colour hue (APHA) of the resins obtained after polymerisation.
Consequently, the purpose of the present invention is to provide an .epsilon.-caprolactone which presents few discoloration risks during monomer formation/storage and during polymer formation as well as use thereof and to provide a method of producing such an .epsilon.-caprolactone. The purpose of the invention is also to provide polycaprolactone(s) having low discolorability by using the .epsilon.-caprolactone and to provide a method of producing these polycaprolactones.
DISCLOSURE OF THE INVENTION
As a result of investigations concerning compounds being factors of the above-mentioned discoloration, the inventor of the present invention has discovered how to obtain .epsilon.-caprolactone having improved storage-discoloration resistance and thermal-discoloration resistance via increasing the purity of .epsilon.-caprolactone up to 99.8% by weight and reducing the amount of specific impurities until a determined level and via treating the discoloration agents by distillation after addition of a specific element of the 4A group or a compound containing this element. Further, it has been discovered that polycaprolactone(s) having improved color hue can be produced by using the above-mentioned .epsilon.-caprolactone.
In other words, the first aspect of the invention provides caprolactone having a purity of at least 99.8% by weight and having a total concentration of not more than 200 ppm based on area ratio of components having a relative retention time of not more than 0.6 (low-boiling components), the relative retention time of .epsilon.-caprolactone being set to 1.00 in a gas-chromatographic analysis under determined conditions.
The second aspect of the invention provides .epsilon.-caprolactone having a purity of at least 99.8% by weight and having a total concentration of not more than 200 ppm based on area ratio of components having a relative retention time of not more than 0.6 (low-boiling components) and total concentration from 100 to 1,000 ppm based on area ratio of components having a relative retention time of more than 0.6 and less than 1.0
REFERENCES:
patent: 4313879 (1982-02-01), Klenk et al.
Daicel Chemical Industries Ltd.
Owens Amelia
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