Process for preparing 3-cyano-3,5,5-trimethylcyclohexanone
View Patent ↗The present invention refers to the preparation of 3-cyano-3,5,5-trimethylcyclohexanone (isophorone nitrile, abbreviation IPN) using a calcium alkoxide, particularly calcium ethoxide, as catalyst.
1. A method for preparing isophorone nitrile, the method comprising:
reacting isophorone and hydrocyanic acid to form isophorone nitrile in a heterogeneous phase in the presence of a calcium alkoxide catalyst at a reaction temperature of from 80 to 130° C. for a reaction time of from 5 to 180 minutes,
wherein a BET surface area of the calcium alkoxide is at least 5 m 2 /g.
2. The method of claim 1 , wherein the calcium alkoxide has an apparent density of at least 250 g/l.
3. The method of claim 1 , wherein the calcium alkoxide catalyst is calcium ethoxide.
4. The method of claim 3 , wherein
the calcium ethoxide has a BET surface area, measured with a pulverulent sample, of at least 5 m 2 /g, and an apparent density of at least 250 g/l.
5. The method of claim 3 , wherein the calcium ethoxide has at least one endothermic peak in the range of 70-130° C. and DSC heat flows of from 0.35 to 0.55 mW/mg in DSC.
6. The method of claim 3 , wherein the calcium ethoxide has an average particle size represented by a d50 value of from 10 to 200 μm.
7. The method of claim 3 , wherein the calcium ethoxide has a BET surface area of greater than 8 m 2 /g, and an apparent density in the range of 290 g/l to 550 g/l.
8. The method of claim 3 , wherein the calcium ethoxide has a BET surface area of greater than 12 m 2 /g, and an apparent density in the range of 290 g/1 to 550 g/l.
9. The method of claim 1 , wherein the catalyst is present as powder, pellets, granulate, or extrudate.
10. The method of claim 1 , wherein said reacting occurs in the presence or absence of at least one inert solvent.
11. The method of claim 1 , wherein isophorone is present in a molar excess, based on hydrocyanic acid, and no external solvent is added.
12. The method of claim 1 , wherein a molar ratio of isophorone/hydrocyanic acid is >1:1.
13. The method of claim 1 , wherein a molar ratio of isophorone/hydrocyanic acid is from 19:1 to 1.2:1.
14. The method of claim 1 , wherein a portion of isophorone is charged and, after heating to a reaction temperature, a mixture of isophorone and hydrocyanic acid is added in a molar ratio of isophorone/hydrocyanic acid >1:1 in the presence of the catalyst.
15. The method of claim 1 , wherein said reacting occurs at the reaction temperature of from 80 to 100° C.
16. The method of claim 1 , wherein said reacting occurs at from 0.01 to 10 bar.
17. The method of claim 1 , wherein the reaction time is from 5 minutes to 90 minutes.
18. The method of claim 1 , wherein said reacting is carried out biphasically.
19. The method of claim 1 , wherein said reacting is carried out in a fixed-bed reactor operated in a continuous mode.
20. The method of claim 1 , wherein said reacting is carried out biphasically with a fixed-bed reactor operated in a continuous mode with a presaturator.
21. The method of claim 1 , wherein said reacting is carried out by a slurry method.