Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2001-02-15
2002-05-14
Siegel, Alan (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
Reexamination Certificate
active
06388140
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of producing a cyclododecanone compound. More particularly, the present invention relates to a method of producing a cyclododecanone compound by an isomerization of the corresponding epoxycyclododecane compound in the presence of a catalyst comprising lithium bromide and/or lithium iodide in an inert gas atmosphere. Cyclododecanone compounds are useful as materials for producing laurolactum, dodecanedioic acids, dodecane diols and perfumes.
2. Description of the Related Art
A plurality of reports on methods of producing cyclododecanone compounds by isomerization of epoxycyclododecane compounds in the presence of a catalyst comprising an alkali metal halide have been published.
For example, German Patent (DE) No. 3,601,380 discloses a method in which cyclodeca-3,7-diene-1-one is produced in a yield of 98.7% by an isomerization reaction of 1,2-epoxycyclododeca-5,9-diene in the presence of sodium iodide catalyst in a reaction medium consisting of polyethyleneglycol. Also, German Patent (DE) No. 3,744,094 discloses a method in which cyclododecanone is produced in a yield of 94% by an isomerization reaction of an epoxycyclododecane in the presence of a lithium chloride catalyst in a reaction medium consisting of N-methylpyrrolidone and/or N,N′-dimethylethyleneurea.
The prior methods mentioned above are disadvantageous in that since a polar solvent such as polyethyleneglycol or N,N′-dimethylethyleneurea is employed, the recovery and decomposition of the solvent may cause the cost of the reaction to increase, and the reaction apparatus is required to have a high pressure resistant. Further, a dilution effect and a salvation effect of the polar solvent on the reaction system cause the reaction rate to decrease and the scale of the reaction apparatus to be large.
Soviet Union (SU) Patent No. 407,874 discloses an isomerization reaction of an epoxycyclododecane compound in the presence of anhydrous LiBr without using a solvent. In examples disclosed in the SU patent, it is reported that when the isomerization was carried out at a reaction temperature of 120 to 130° C. for 18 hours or at a temperature of 200° C. for 3 hours, the target cyclododecanone was obtained in a yield of about 100% in the former or 83.3% in the latter. In the former case, the reaction time was too long and thus the reaction conditions may not be practical. Also, in the latter case, a by-product having a high boiling temperature was produced and a discoloration of the reaction liquid was found. When the catalyst is recycled and repeatedly used, the high boiling temperature product accumulated in the reaction system causes the reaction to be affected and a specific procedure for removing the high boiling temperature product to be necessary.
It is assumed that the reaction rate can be increased by increasing the concentration of the catalyst in the reaction system. In the reaction system disclosed in the above-mentioned SU patent, the concentration of the LiBr dissolved in the reaction system was saturated, and thus a further increase in the LiBr concentration was impossible. When the reaction temperature is increased to increase the reaction rate, undesirable side reactions occur, the yield of the target product decreases, high boiling temperature substances are produced and the reaction system is discolored.
Further, Zh. Org. Khim (1990), 26(7), 1497-1500 reports that when an isomerization of epoxycyclododecane was carried out at a temperature of 150° C. for 10 hours in the presence of a catalyst comprising lithium bromide without using a solvent, a target cyclodedecanone was produced in a yield of 96.6%, and when the same isomerization as above was carried out except that the catalyst comprised lithium iodide, and the reaction temperature and time were 150° C. and 5 hours, the target cyclodedecanone was obtained in a yield of 91.2%. However, the report is quite silent as to the reaction atmospheric gas. In the method of the report, to increase the conversion of the starting compound to the target compound to about 100%, a long reaction time is necessary, and the long reaction time causes high boiling temperature substances to be produced.
In the case where a cyclododecanone compound is industrially produced by an isomerization of an epoxycyclododecanone compound, since the boiling temperature of the starting epoxycyclododecane compound is approximately equal to that of the target cyclodedecanone compound, usually the separation of the starting compound from the target product by distillation is extremely difficult. Thus, in order to produce the cyclododecanone compound in a high degree of purity, it is necessary to control the conversion of the epoxycyclododecane compound to approximately 100%. For this, it is absolutely necessary to increase the isomeization reaction rate. To increase the reaction rate, an increase in the reaction temperature may be tried and/or an increase in the content of the catalyst in the reaction system may be attempted.
However, as mentioned above, the increase in the reaction temperature causes undesirable side reactions to occur, high boiling temperature substances to be produced, the yield of the target cyclododecanone compound to decrease.
On other hand, to increase the conversion of the starting epoxycyclododecane compound, it may be considered to further increase the concentration of the catalyst in the reaction system. However, the increase in the catalyst concentration is not practical in consideration of the solubility of the catalyst in the reaction system and the increase in production cost of the target product due to the increase in the amount of the catalyst.
As mentioned above, the conventional methods of producing the cyclododecanone compounds by the isomerization of epoxycyclododecane compounds are unsatisfactory due to a low reaction rate, a low conversion of the starting compound, a low selectivity of the target compound, production of undesirable high boiling temperature substance, and a low efficiency.
Therefore, a new method enabling the industrial production of the target cyclododecanone compound at a high reaction rate, with a high conversion of the starting compound, with a high selectivity to the target compound and with a high efficiency, while the side reaction for the production of undesired high boiling temperature substances is controlled, is strongly demanded.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method of producing a cyclododecanone compound by isomerization of an epoxycyclododecane compound at a high reaction rate at a high conversion at a high selectivity, with a high industrial efficiency, while substantially preventing the production of high boiling temperature substances.
The inventors of the present invention made an extensive study of means for attaining the above-mentioned object, and found that when the isomerization of an epoxycyclododecane compound is carried out in the presence of lithium bromide and/or lithium iodide in an inert gas atmosphere, the target cyclododecanone compound can be produced at an enhanced reaction rate, and all the above-mentioned problems of the prior acts can be solved. The present invention has been completed on the basis of the above-mentioned finding.
The method of the present invention for producing a cyclododecanone compound comprises isomerizing an epoxycyclododecane compound in the presence of a catalyst comprising at least one member selected from the group consisting of lithium bromide and lithium iodide, without using a solvent or in a non-polar solvent, in an inert gas atmosphere.
In the method of the present invention for producing a cyclododecanone compound, the epoxycyclododecane compound is preferably selected from the group consisting of saturated and unsaturated monoepoxy-cycloaliphatic compounds having a cyclic structure formed from 12 carbon atoms and an epoxy structure formed from one oxygen atom and two carbon atoms of the 12 carbon atoms being adjacent t
Doi Takashi
Kashiwagi Kohichi
Matsuura Tsunao
Niida Sadao
Nishio Masayuki
Morgan & Lewis & Bockius, LLP
Siegel Alan
Ube Industries Ltd.
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