Hydrogenation of catmint oil
View Patent ↗Disclosed are methods for treating catmint oil. The treated catmint oil can be used for the production of hydrogenated catmint oil, which is enriched in the insect repellent, dihydronepetalactone.
1. A process for preparing hydrogenated catmint oil, comprising:
(a) contacting a beginning amount of crude catmint oil with Na 2 B 4 O 7 .10H 2 O;
(b) distilling the beginning amount of crude catmint oil to produce (i) a distillate fraction comprising volatile components driven off from the crude catmint oil, wherein the weight of the distillate fraction comprises about 2% to about 20% of the weight of the beginning amount of crude catmint oil, and (ii) a pot fraction;
(c) contacting the pot fraction produced in step (b) with hydrogen and a hydrogenation catalyst to produce hydrogenated catmint oil; and
(d) optionally, recovering the hydrogenated catmint oil of step (c).
2. The process of claim 1 wherein the weight of the distillate fraction comprises about 5% to about 10% of the weight of the beginning amount of crude catmint oil.
3. The process of claim 1 wherein the step of distilling (a) comprises a step of (i) vacuum distilling, (ii) steam distilling, (iii) solvent distilling, or (iv) steam distilling followed by solvent distilling.
4. The process of claim 3 which comprises a step of solvent distilling, or of steam distilling followed by solvent distilling, and wherein, at the beginning of solvent distilling, the weight of the solvent comprises about 5% to about 60% of the combined weight of catmint oil plus solvent.
5. The process of claim 4 wherein, at the beginning of solvent distilling, the weight of the solvent comprises about 10% to about 25% of the combined weight of catmint oil plus solvent.
6. The process of claim 3 which comprises a step of solvent distilling, or of steam distilling followed by solvent distilling, and wherein a solvent comprises a C 1 to C 5 straight-chain or branched alcohol.
7. The process of claim 6 wherein the alcohol is selected from the group consisting of methanol, ethanol, isopropanol and n-propanol.
8. The process of claim 3 wherein steam distilling, solvent distilling, or steam distilling followed by solvent distilling, is performed under vacuum.
9. The process of claim 1 wherein the pot fraction is contacted with hydrogen and a hydrogenation catalyst at a temperature of about −10° C. to about 200° C.
10. The process of claim 1 wherein the pot fraction is contacted with hydrogen and a hydrogenation catalyst at a temperature of about 25° C. to about 250° C.
11. The process of claim 1 wherein the pot fraction is contacted with hydrogen at a hydrogen pressure of about 0.1 MPa to about 20.7 MPa.
12. The process of claim 1 wherein the pot fraction is contacted with hydrogen and a hydrogenation catalyst comprising a catalytic metal selected from elements from the group consisting of iron, ruthenium, rhenium, copper, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, alloys or compounds thereof; and combinations thereof.
13. A process for preparing hydrogenated catmint oil comprising:
(a) contacting crude catmint oil with Na 2 B 4 O 7 .10H 2 O to produce a first treated catmint oil;
(b) separating the first treated catmint oil from the oxidizing agent to produce a second treated catmint oil;
(c) contacting the second treated catmint oil with hydrogen and a hydrogenation catalyst to produce hydrogenated catmint oil; and
(d) optionally recovering the hydrogenated catmint oil.
14. The process of claim 13 wherein the second treated catmint oil is contacted with hydrogen and a hydrogenation catalyst at a temperature of about −10° C. to about 200° C.
15. The process of claim 13 wherein the second treated catmint oil is contacted with hydrogen and a hydrogenation catalyst at a temperature of about 25° C. to about 250° C.
16. The process of claim 13 wherein the second treated catmint oil is contacted with hydrogen at a hydrogen pressure of about 0.1 MPa to about 20.7 MPa.
17. The process of claim 13 wherein the second treated catmint oil is contacted with hydrogen and a hydrogenation catalyst comprising a catalytic metal selected from elements from the group consisting of iron, ruthenium, rhenium, copper, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, alloys or compounds thereof; and combinations thereof.