Process for the synthesis of lauryllactam (L12) by gas phase catalytic rearrangement of cyclododecanone oxime
View Patent ↗The present invention relates to a process for the preparation of lauryllactam in which a Beckmann rearrangement of cyclododecanone oxime is carried out. Said process is carried out in the gas phase at a temperature of between 180 and 450° C. in the presence of a microporous material having a three-dimensional inorganic main structure composed of tetrahedra connected via a common edge, called zeolite.
1. A process for the preparation of lauryllactam comprising carrying out a Beckmann rearrangement of cyclododecanone oxime in the gas phase at a temperature of between 180 and 450° C. in the presence of a microporous zeolite material having a three-dimensional inorganic main structure composed of tetrahedra connected via a common edge, wherein said zeolite is a zeolite exhibiting a pore distribution within the region of the wide pores having an opening delimited by rings comprising 12 tetrahedra.
2. The process according to claim 1 , wherein:
a) the cyclododecanone oxime is either dissolved in a solvent chosen from alcohols, hydrocarbons, and mixtures of alcohols and hydrocarbons, or is in the molten state, to form a cyclododecanone stream;
b) the cyclodecanone stream from step a) is vaporized and brought into contact with the zeolite, optionally using a carrier gas;
c) the lauryllactam is separated from the solvent, from the optional carrier gas and from any cyclododecanone oxime which has not been converted.
3. The process according to claim 1 , wherein the temperature of the rearrangement is between 225 and 400° C.
4. The process according to claim 3 , wherein the temperature is between 225 and 375° C.
5. The process according to claim 1 , wherein the rearrangement is carried out at a pressure of between 50 and 700 mbar absolute.
6. The process according to claim 1 , wherein the zeolite is a USY zeolite.
7. The process according to claim 1 , in which the zeolite is selected from the group of zeolites consisting of a zeolite which has aluminium and/or boron as framework heteroatom, a zeolite which initially has aluminium and/or boron as framework heteroatom and which has been subjected to a dealumination/deboration treatment, a β zeolite, a β zeolite which has aluminium and/or boron as framework heteroatom, and a β zeolite which initially has aluminium and/or boron as framework heteroatom and which has been subjected to a dealumination/deboration treatment.
8. The process according to claim 7 , wherein the zeolite is a zeolite which initially has aluminium and/or boron as framework heteroatom and which has been subjected to a dealumination/deboration treatment.
9. The process according to claim 8 , wherein the zeolite is a β zeolite which initially has aluminium and/or boron as framework heteroatom and which has been subjected to a dealumination/deboration treatment.
10. The process according to claim 9 , in which the β zeolite which initially has aluminium as framework heteroatom is subjected to a dealumination resulting in an Si/Al atomic ratio of greater than 50.
11. The process according to claim 10 , in which the β zeolite which initially has the aluminium atom as framework heteroatom is subjected to a dealumination resulting in an Si/Al atomic ratio of greater than 80.
12. The process according to claim 11 , in which the β zeolite which initially has the aluminium atom as framework heteroatom is subjected to a dealumination resulting in an Si/Al atomic ratio of greater than 150.
13. The process according to claim 9 , in which the β zeolite which initially has the boron atom as framework heteroatom is subjected to a deboration resulting in an Si/B atomic ratio of greater than 20.
14. The process according to claim 13 , in which the β zeolite which initially has the boron atom as framework heteroatom is subjected to a deboration resulting in an Si/B atomic ratio of greater than 40.
15. The process according to claim 8 , in which the β zeolite which initially has the aluminium atom and the boron atom as framework heteroatom is subjected to a dealumination/deboration resulting in an Si/Al ratio of greater than 50 and an Si/B ratio of greater than 20.
16. The process according to claim 15 , in which the β zeolite which initially has the aluminium atom and the boron atom as framework heteroatom is subjected to a dealumination/deboration resulting in an Si/Al ratio of greater than 150 and an Si/B ratio of greater than 30.
17. The process according to claim 2 , wherein the cyclododecanone oxime is introduced in the molten state.
18. The process according to claim 2 , wherein the cyclododecanone oxime is dissolved in a solvent chosen from alcohols and hydrocarbons and wherein the alcohol is chosen from methanol, ethanol or isopropanol.
19. The process according to claim 2 , wherein the solvent is chosen from isopropanol/cyclohexane and ethanol/cyclohexane mixtures.
20. The process according to claim 1 , wherein the zeolite is regenerated.
21. The process according to claim 20 , wherein the zeolite is regenerated as soon as a fall in the yield of between 10 and 20% is observed.