Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2001-10-19
2003-02-11
Richter, Johann (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C568S350000, C568S356000
Reexamination Certificate
active
06518461
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of producing a cyclododecanone compound which is useful as a material for producing laurolactam, dodecanedioic acid and dodecane diol. More particularly, the present invention relates to a process for producing a cyclododecanone compound, for example, cyclododecanone, cyclododecenone, cyclododecadienone or cyclododecatrienone by catalytically isomerizing a corresponding epoxycyclododecanone compound, for example, epoxycyclododecane, epoxycyclododecene, epoxycyclododecadiene or epoxycyclododecatriene, with a high conversion of the epoxycyclododecane compound with a high selectivity to the cyclododecanone compound, within a relatively short time.
2. Description of the Related Art
Methods for producing a cyclododecanone by isomerizing a corresponding epoxycyclododecane compound in the presence of a catalyst consisting of a lithium halide are known from a plurality of reports.
For example, German Patent No. 3,744,094 discloses an isomerization of an epoxycyclododecane in the presence of a catalyst consisting of lithium chloride in a reaction medium consisting of N-methylpyrrolidone or N,N′-dimethylethyleneurea to produce cyclododecanone with a yield of 94%.
Also, German Patent No. 3,601,380 discloses that, by isomerization of 1,2-epoxy-5,9-cyclododecadiene in the presence of a catalyst consisting of sodium iodide in a reaction medium consisting of a polyethylene glycol (NaI: 3 wt %, 195° C., 9 hours), cyclododeca-3,7-diene-1-one is produced with a yield of 98.7%.
In each of the above-mentioned methods, however, as a polar solvent is employed as a reaction medium, means for recovering the solvent or for decomposing the solvent must be added to the production system for the target compound and this causes the production cost of the target compound to increase.
Further, the reaction rate of the isomerization reaction is decreased by a dilution effect or a solvation effect of the solvent, and thus the reaction time necessary to effect the isomerization reaction at a conversion close to 100% becomes long. Also, as the reaction is carried out in a batch type reaction system, the above-mentioned methods are unsuitable for industrially producing the target compound in a large quantity with a high efficiency.
Further, SU Patent 407,874 discloses an isomerization reaction of an epoxycyclododecane, in the presence of a catalyst consisting of anhydrous LiBr, in no solvent. In examples of the SU patent, it is reported that, when the reaction was carried out in an amount of LiBr of 4% by weight at a reaction temperature of 120 to 130° C. for a reaction time of 18 hours or in an amount of LiBr of 3.3% by weight at a reaction temperature of 200° C. for a reaction time of 3 hours, the target cyclododecanone was obtained at a yield of 100% or 83.3%.
In the former example, the reaction time is too long, and thus the reaction is not practical, and in the later example, the selectivity to the target compound is low and a by-product having a high boiling temperature was produced.
The high boiling temperature by-product is disadvantageous in that when the catalyst is recovered from the reaction mixture after the reaction is completed and recycled to the reaction procedure, the high boiling temperature by-product is accumulated in the reaction system to affect the reaction, and thus an additional procedure for removing the high boiling temperature by-product from the reaction mixture becomes necessary.
In this connection, it may be considered that for the purpose of increasing the reaction rate, the concentration of the catalyst in the reaction system should be increased. However, in the method of the former example, since the solubility of LiBr in the reaction system is saturated, the concentration of the catalyst cannot be increased. In the method of the later example, the reaction temperature is established at a high level to increase the reaction rate. This high temperature causes a side reaction to occur, the yield of the target compound to be decreased, and the high boiling temperature by-product to be produced.
Further, Zh. Org. Khim (1990), 26(7), 1497-1500, discloses that, when an isomerization reaction of an epoxycyclododecane was carried out in the presence of 2.3 molar % of a catalyst consisting of LiBr (lithium bromide) at a reaction temperature of 150° C. for a reaction time of 10 hours, the target cyclododecanone was obtained at a yield of 96.6%, and when the reaction of the epoxycyclododecane was effected in the presence of 1.5 molar % of LiI (lithium iodide) at 150° C. for 5 hours, the target cyclododecanone was obtained at a yield of 91.2%. In the case of this report, however, it is assumed that, to make the conversion of the epoxycyclododecane close to 100%, a very long reaction time is necessary. Also, the reaction of the report was effected in a batch-type reaction system, and thus no continuous method for the reaction is disclosed in the report.
In the case where a cyclododecanone compound is produced by isomerizing an epoxycyclododecane compound, since the boiling temperature of the epoxycyclododecane compound is approximately equal to that of the cyclododecanone compound, there are many cases in which the separation of the two compounds from each other by distillation is very difficult from an industrial point of view. Also, since the two compounds are similar, in physical and chemical properties, to each other, the separation on refining of the two compounds by crystallization or extraction is difficult. Therefore, to produce the cyclododecanone compound with a high degree of purity, it is necessary that the conversion of the epoxycyclododecane compound is controlled to approximately 100%. For this purpose, it is possible to increase the reaction temperature or the content of the catalyst.
However, as mentioned above, an increase in the reaction temperature causes frequent occurrence of side reactions and thus the production of the high boiling temperature compounds is promoted and the yield of the target cyclododecanone compound is reduced.
On other hand, as a measure to enhance the conversion of the epoxycyclododecane compound, it is possible to increase the content of the catalyst in the reaction system. However, the increase in the catalyst content may cause a difficulty in the dissolution of the catalyst in the reaction system and may make the cost of the reaction increase. Thus, this measure is not practical.
All of the reaction procedures of the above-mentioned prior arts are carried out in batch type reactor systems and thus are disadvantageous in that the process operations are complicated, the safety of the operations is unsatisfactory and the operation cost is high. In fact, the isomerization reaction is an exothermic reaction. Therefore, when the cyclododecanone compound is industrially produced in a large quantity by the batch type reactor system, a large amount of heat is generated. In practice, it is important to remove the heat with a high efficiency. For example, when a large amount of an epoxycyclododecane compound is catalytically isomerized at a temperature of 200° C. in a batch type reactor, since the removal of the generated reaction heat is difficult, the reaction temperature may be rapidly increased to such an extent that bumping of the liquid reaction mixture occurs.
As mentioned above, in the conventional technology, it has not yet been possible to isomerize the epoxycyclododecane compound in a short reaction time at a conversion of the compound of approximately 100% with a selectivity to the target compound of approximately 100%. Further, since the known isomerization method is carried out in a batch type reactor, the target cyclododecanone compound cannot be continuously and safely provided. Namely, a continuous process for producing the cyclododecanone compound in an industrial scale has not yet been established.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a process for continuously producing a cyclododecanone compound i
Doi Takashi
Matsuura Tsunao
Niida Sadao
Nishio Masayuki
Sugise Ryoji
Richter Johann
UBE Industries Ltd.
Witherspoon Sikarl A.
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