METHOD FOR PRODUCING LAUROLACTAM, DEVICE FOR SYNTHESIZING SAME, LAUROLACTAM COMPOSITION PRODUCED THEREBY, AND METHOD FOR PRODUCING POLYLAUROLACTAM USING SAME

Abstract

Provided are a method of preparing laurolactam including: a) synthesizing laurolactam by Bechmann rearrangement of cyclododecanone oxime under a catalyst system, b) mixing the laurolactam synthesized in a) with a good solvent and removing the catalyst system, and c) mixing the laurolactam from which the catalyst system has been removed in b) with a poor solvent and performing recrystallization, a synthesis device thereof, a laurolactam composition prepared therefrom, and a method of preparing polylaurolactam using the laurolactam composition.

Claims

1. A method of preparing laurolactam, the method comprising: a) synthesizing laurolactam by Bechmann rearrangement of cyclododecanone oxime under a catalyst system, b) mixing the laurolactam synthesized in a) with a good solvent and removing the catalyst system, and c) mixing the laurolactam from which the catalyst system has been removed in b) with a poor solvent and performing recrystallization.

2. The method of preparing laurolactam of claim 1, wherein the Bechmann rearrangement in a) is synthesis of laurolactam from cyanuric chloride by the catalyst system including cyanuric chloride (TCT) and zinc chloride (ZnCl.sub.2), in the presence of a solvent including isopropylcyclohexane (IPCH).

3. The method of preparing laurolactam of claim 2, wherein a) further includes removing the solvent by distilling the synthesized laurolactam.

4. The method of preparing laurolactam of claim 1, wherein in b), the catalyst system is removed using a difference in solubility of the catalyst system and the laurolactam in the good solvent.

5. The method of preparing laurolactam of claim 1, wherein the good solvent is a C1 to C4 hydrocarbon organic solvent containing one or two or more functional groups selected from the group consisting of a hydroxyl group, an amine group, and a thiol group.

6. The method of preparing laurolactam of claim 1, wherein in c), the laurolactam is recrystallized using a difference in solubility of laurolactam in the good solvent and the poor solvent.

7. The method of preparing laurolactam of claim 1, wherein the good solvent and the poor solvent are miscible.

8. The method of preparing laurolactam of claim 1, wherein the poor solvent is distilled water or deionized water.

9. The method of preparing laurolactam of claim 1, wherein the good solvent and the poor solvent are injected at a weight ratio of 1:1.5 to 1:3.

10. The method of preparing laurolactam of claim 1, further comprising: evaporating the recrystallized laurolactam to remove heavies in a liquid phase and/or a solid phase and separating laurolactam in a gas phase.

11. A laurolactam synthesis device comprising: a first reactor for synthesizing laurolactam by Bechmann rearrangement of cyclododecanone oxime under a catalyst system, an evaporator for removing a solvent from the laurolactam synthesized in the first reactor, a second reactor for mixing the laurolactam from which the solvent has been removed in the evaporator with a good solvent and removing the catalyst system, and a third reactor for mixing the laurolactam from which the catalyst system has been removed in the second reactor with a poor solvent and performing recrystallization.

12. The laurolactam synthesis device of claim 11, further comprising: a filter for removing the catalyst system precipitated in the second reactor.

13. The laurolactam synthesis device of claim 11, further comprising: a film evaporator for separating heavies from the recrystallized laurolactam.

14. A laurolactam composition synthesized by the method of claim 1.

15. The laurolactam composition of claim 14, wherein the laurolactam composition includes a catalyst system used in Bechmann rearrangement at 5 wt % or less with respect to a total weight of the laurolactam composition.

16. A method of preparing polylaurolactam comprising: anionically polymerizing the laurolactam composition of claim 14 in the presence of an anionic initiator to prepare polylaurolactam.

17. The method of preparing polylaurolactam of claim 16, wherein the anionic initiator includes one or two or more selected from the group consisting of NaH, n-BuLi, KH, and LiH.

18. The method of preparing polylaurolactam of claim 16, wherein the anionic polymerization is performed at 200 to 350° C. for 10 to 60 minutes.

19. The method of preparing polylaurolactam of claim 16, wherein the polymerized polylaurolactam has a weight average molecular weight of more than 6,000.

Description

EXAMPLES

Preparation Example 1

[0066] 3 g of cyclododecanone oxime, 12 g of isopropylcyclohexane, 0.045 g of cyanuric chloride, and 0.03 g of zinc chloride were added to a 100 ml round flask. Then, the temperature was adjusted to 95° C. using a heating mantle, and the reaction was performed by stirring at 200 rpm or more. A reaction completion time was 5 minutes, the conversion rate of cyclododecanone oxime was 99% or more, and the selectivity of laurolactam was 99% or more.

Example 1

[0067] 100 g of the product of Preparation Example 1 was injected into an evaporator, and was distilled at 150° C. to remove IPCH from the top of the evaporator. 700 g of ethanol was injected into a produced brown solid (laurolactam before purification) and dissolved in a flask. Floating solid (catalyst) was removed using a 0.22 μm filter, and 1,600 g of water was injected into laurolactam (LL) dissolved in ethanol to recrystallize a LL solid. A solid was separated from the recrystallized LL using a filter, a film evaporator was used to remove heavies from the bottom, LL was removed from the top, and a residual catalyst content and a LL yield were measured and are shown in the following Table 1.

[0068] Subsequently, 50 g of LL and a catalyst were added to a 100 ml round flask at a weight ratio of LL:NaH:ethylene bis stearamide (EBS):tetraethyl orthosilicate (TEOS):CO.sub.2=100:0.6:0.36:0.15:0.15, using the prepared LL, anionic polymerization reaction was performed at 240° C. for 30 minutes to prepare PA 12 (polyamide 12), and the polymerization degree of PA 12 is shown in the following Table 1.

Example 2

[0069] The process was performed in the same manner as in Example 1, except that 300 g of ethanol was injected, thereby separating LL, and a residual catalyst content and a LL yield were measured and are shown in the following Table 1, respectively.

[0070] Subsequently, an anionic polymerization reaction was performed in the same manner as in Example 1 to prepare PA 12, and the polymerization degree of PA 12 is shown in the following Table 1.

Example 3

[0071] The process was performed in the same manner as in Example 1, except that 700 g of water was injected into laurolactam (LL) dissolved in ethanol, thereby separating LL, and a residual catalyst content and a LL yield were measured and are shown in the following Table 1, respectively.

[0072] Subsequently, an anionic polymerization reaction was performed in the same manner as in Example 1 to prepare PA 12, and the polymerization degree of PA 12 is shown in the following Table 1.

Comparative Example 1

[0073] 100 g of the product of Preparation Example 1 was injected into an evaporator, and was distilled at 150° C. to remove IPCH from the top of the evaporator. A film evaporator was used to remove heavies from the produced brown solid in the bottom, LL was removed from the top, and a residual catalyst content and a LL yield were measured and are shown in the following Table 1, respectively.

[0074] Subsequently, an anionic polymerization reaction was performed in the same manner as in Example 1 to prepare PA 12, and the polymerization degree of PA 12 is shown in the following Table 1.

Comparative Example 2

[0075] The process was performed in the same manner as in Example 1, except that water was not injected into laurolactam (LL) dissolved in ethanol, thereby separating LL, and a residual catalyst content and a LL yield were measured and are shown in the following Table 1, respectively.

[0076] Subsequently, an anionic polymerization reaction was performed in the same manner as in Example 1 to prepare PA 12, and the polymerization degree of PA 12 is shown in the following Table 1.

[0077] Method of Measuring Content of Residual Catalyst System

[0078] Since laurolactam is a solid at room temperature, it is not distinguished from a solid catalyst used in the synthesis, but when it is dissolved at 150° C., the catalyst remains as a black solid, and thus, it may be confirmed whether the solid catalyst remains. The weight of the catalyst remaining in the laurolactam prepared in Preparation Example 1 was measured after separating the catalyst as a solid at a high temperature, or using a solvent which may dissolve laurolactam.

[0079] Method of Measuring Yield of Laurolactam

[0080] 100 g of the product of Preparation Example 1 was measured GC to calculate the content of laurolactam (L.sub.1), and the content of laurolactam (L.sub.2) obtained in the top of the film evaporator of Example 1 was measured to calculate the yield of laurolactam (L.sub.2/L.sub.1*100, %).

[0081] Method of Measuring Molecular Weight (Polymerization Degree) of PA 12

[0082] In the polymerization reactor in which the anionic polymerization reaction was completed, an agitator torque value was calculated, and the value was inversely calculated to calculate the weight average molecular weight of PA 12.

TABLE-US-00001 TABLE 1 Polymerization Laurolactam before Residual degree of PA 12 purification:ethanol Ethanol:water LL yield catalyst content (weight average (weight ratio) (weight ratio) (%) (wt %) molecular weight) Example 1 1:7 1:2.3 80% Trace 10,000 (undetected) Example 2 1:3 1:5.3 50% 500 (ppm)  6,000 Example 3 1:7 1:1   60% Trace 10,000 (undetected) Comparative — — 90%  1 (wt %) Not polymerized Example 1 Comparative 1:7 — 20% Trace 10,000 Example 2 (undetected)

[0083] Referring to Table 1, in Examples 1 to 3, the residual catalyst was substantially removed, and as a result of performing the anionic polymerization reaction using the purified laurolactam, PA 12 was able to be prepared. However, it was confirmed that Example 1 in which LL was purified at a preferred weight ratio of the good solvent and the poor solvent had a more improved yield of LL than Example 3. Meanwhile, in Example 2, ethanol was added in a small amount as compared with the amount of laurolactam before purification, and since laurolactam which is not dissolved in ethanol was removed with the remaining solid catalyst, the LL yield was decreased, and since a material in which laurolactam and a small amount (500 ppm) of the catalyst were agglomerated passed the filter and remained, PA 12 having a low molecular weight (6,000) was prepared. In Comparative Example 1, LL was purified simply by an evaporator without adding the good solvent and the poor solvent of the present invention, and since the activity of the anionic initiator (NaH) of the anionic polymerization reaction was decreased by the catalyst remaining at a high content in the purified LL composition, PA 12 was not able to be polymerized. In addition, in Comparative Example 2, ethanol was added in an excess of water, and a part of LL was not precipitated as a solid and was present in a state of being dissolved in ethanol, and entrainment with ethanol in the evaporator occurred, so that the LL yield was significantly decreased, and thus, it was confirmed that application to a commercial process was difficult.

[0084] Hereinabove, although the present invention has been described by specified matters and specific exemplary embodiments, they have been provided only for assisting in the entire understanding of the present invention. Therefore, the present invention is not by the specific matters limited to the exemplary embodiments. Various modifications and changes may be made by those skilled in the art to which the present invention pertains from this description. Therefore, the spirit of the present invention should not be limited to the above-described exemplary embodiments, and the following claims as well as all modified equally or equivalently to the claims are intended to fall within the scope and spirit of the invention.