Organic compounds -- part of the class 532-570 series – Organic compounds – Unsubstituted hydrocarbyl chain between the ring and the -c-...
Reexamination Certificate
2003-01-16
2003-11-18
Kifle, Bruck (Department: 1624)
Organic compounds -- part of the class 532-570 series
Organic compounds
Unsubstituted hydrocarbyl chain between the ring and the -c-...
Reexamination Certificate
active
06649757
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a process for producing laurolactam from cyclododecanone. More particularly, the present invention relates to a process for producing laurolactam having a high degree of purity from cyclododecanone used as a starting material.
Laurolactam is useful as a material for producing synthetic resins such as polyamide resins.
(2) Description of the Related Art
As a conventional method of producing laurolactam, a method in which cyclodododecanone, having been prepared by oxidizing cyclododecane with molecular oxygen-containing gas and dehydrogenating the resultant cyclydodecanol, is reacted, as a starting material, with a hydroxylamine mineral acid salt to prepare cyclododecanoneoxime and the resultant cyclododecanoneoxime is subjected to the Beckmann rearrangement reaction to produce the target laurolactam, is known. As another method of producing cyclododecanone, a method in which epoxycyclododecadiene is reduced with hydrogen and the resultant epoxycyclododecane is isomerized with an alkali metal salt, etc., to prepare the target cyclododecanone, is known.
In the method of producing cyclododecanone using, as a starting material, epoxycyclododecadiene, in the case where the reduction of epoxycyclododecadiene with hydrogen is incompletely carried out, the resultant epoxycyclododecane contains an impurity consisting of epoxycyclododecene and the epoxycyclododecene is converted to cyclododecenone by the isomerization reaction. The cyclododecenone is an impurity which is difficult to remove, as an impurity, from the target cyclododecanone by distillation. Also, in the case where cyclododecanol is dehydrogenated, cyclododecenone may be produced as a by-product, when the reaction conditions are inappropriate.
Further it is known that, in the reaction for isomerizing epoxycyclododecane in the presence of an alkali metal salt, undesired compounds having one or more double bonds between carbon atoms, such as cyclododecadiene, cyclododecene and cyclododecenol are produced as by-products.
Further, it is known that, in the method in which cyclododecanone, having been prepared by oxidizing cyclododecane with a molecular oxygen-containing gas and dehydrogenating the resultant cyclododecanol, is employed as a starting material for the production of laurolactam, the cyclododecanone produced by the oxidation of cyclododecane is further oxidized to produce 1,2-diketone compound and &agr;-hydroxyketone compound, and the &agr;-hydroxyketone compound is further converted to 1,2-diketone compound (cyclododecane-1,2-dione) during the dehydrogenation reaction procedure for cyclododecanol.
Where cyclododecanone is produced from a starting material consisting of epoxycyclododecadiene, the 1,2-diketone compound is not directly produced. However, when cyclododecanone is handled at a temperature of 100° C. or more in the presence of a molecular oxygen-containing gas, the 1,2-diketone compound is produced. In this case, the 1,2-diketone compound is an impurity which is difficult to separate from cyclododecanone by distillation.
Furthermore, it is known that in a method for preparing a mixture of cyclododecanol with cyclododecanone, by oxidizing cyclododecane with a molecular oxygen-containing gas, epoxycyclododecane is produced as a by-product, and in the distillation refining procedure for isolating refined cyclododecanone from the mixture, the distilled cyclododecanone fraction contains the above-mentioned epoxycyclododecane as an impurity.
Still further, it is known that in the case where epoxycyclododecadiene is used as a starting material for the production of cyclododecanone, and subjected to an isomerization reaction thereof, a small amount of cycloundecylcarboxyaldehyde is produced as a by-product. The cycloundecylcarboxyaldehyde is an impurity which is difficult to separate from cyclododecanone by distillation.
Also, in the method of preparing a mixture of cyclododecanol with cyclododecanone by oxidizing cyclododecane with a molecular oxygen-containing gas, undecylaldehyde is produced as a by-product and is contained in refined cyclododecanone fraction obtained by distillation of the mixture.
When the aldehyde compound-containing cyclododecanone is subjected to the cyclododecanoneoxime-preparing procedure and then to the Beckmann rearrangement reaction, the aldehyde compound is converted to a corresponding amide compound and the amide compound is kept contained in the target laurolactam. The contained amide compound causes the quality of the resultant laurolactam to be decreased.
Furthermore, it is known from the disclosure of Japanese Examined Patent Publication No. 43-12153 and No. 48-10475 that, in the production of laurolactam by converting cyclododecanone to an oxime thereof and subjecting the resultant cyclododecanoneoxime to the Beckmann rearrangement reaction, if the temperature of the Beckmann rearrangement reaction is too high, the cyclododecanoneoxime is decomposed due to the poor thermal stability thereof, and the resultant laurolactam is unsatisfactory due to the low quality thereof. However, the prior art does not teach or suggest any possible influence of oxygen atom-containing organic compounds having 12 carbon atoms and cycloaliphatic unsaturated hydrocarbon compounds having 12 carbon atoms, for example, carbonyl group-containing C
12
-noncyclo-aliphatic and cycloaliphatic hydrocarbon compounds, epoxy group-containing C
12
-noncyclo-aliphatic and cycloaliphatic hydrocarbon compounds, aldehyde group-containing C
12
-noncyclo-aliphatic and cycloaliphatic hydrocarbon compounds, hydroxyl group-containing C
12
-noncyclo-aliphatic and cycloaliphatic hydrocarbon compounds contained in the starting cyclododecanone material, on the quality of the target laurolactam.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a process for producing laurolactam having high quality, from cyclododecanone, with a high efficiency.
The above-mentioned object can be attained by the process of the present invention for producing laurolactam from cyclododecanone, which comprises reacting cyclododecanone with a hydroxylamine salt of a mineral acid to prepare cyclododecanoneoxime, and converting the resultant cyclododecanoneoxime to laurolactam through the Beckmann rearrangement reaction, wherein a content of each of oxygen atom-containing organic compounds having 12 carbon atoms and cycloaliphatic unsaturated hydrocarbon compounds having 12 carbon atoms, each contained, as an impurity, in cyclododecanone used as a starting material, is controlled to 1,000 ppm or less.
In the process of the present invention for producing laurolactam, the total content of the oxygen atom-containing organic compounds having 12 carbon atoms and the cycloaliphatic unsaturated hydrocarbon compounds having 12 carbon atoms and respectively contained, as impurities, in the starting cyclododecanone material, is preferably controlled to 2,000 ppm or less.
In the process of the present invention for producing laurolactam, the oxygen atom-containing organic compounds having 12 carbon atoms and contained, as impurities, in the starting cyclododecanone material may include noncyclo-hydrocarbon compounds or cycloaliphatic hydrocarbon compounds respectively having at least one carbonyl group per molecule thereof.
In the process of the present invention, for producing laurolactam, the oxygen atom-containing organic compounds having 12 carbon atoms and contained, as impurities, in the starting cyclododecanone material may include noncyclo-hydrocarbon compounds or cycloaliphatic hydrocarbon compounds respectively having at least one epoxy group per molecule thereof.
In the process of the present invention for producing laurolactam, the oxygen atom-containing organic compounds having 12 carbon atoms and contained, as impurities, in the starting cyclododecanone material may include noncyclo-hydrocarbon compounds or cycloaliphatic hydrocarbon compounds respectively having at least one aldehyde group per molecule thereof.
In the process of the
Kawai Joji
Kuroda Nobuyuki
Shimomura Hideo
Kifle Bruck
Piper Rudnick LLP
Ube Industries Ltd.
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