Chemical process to manufacture branched-caprolactone

1. A method of synthesizing an alkyl-caprolactone, the method comprising:

hydrogenating an alkyl-phenol in a trickle bed catalytic reactor to yield a first stream comprising an alkyl-cyclohexanone and an alkyl-cyclohexanol;

providing the first stream to a first distillation column to yield a second stream comprising the alkyl-cyclohexanone;

providing the second stream to a second distillation column to yield a third stream comprising purified alkyl-cyclohexanone;

oxidizing the purified alkyl-cyclohexanone in a liquid phase fixed bed oxidation reactor to yield a fourth stream comprising an alkyl-caprolactone, the alkyl-cyclohexanone, and the alkyl-cyclohexanol;

providing the fourth stream to a third distillation column to yield a fifth stream comprising the alkyl-caprolactone and a sixth stream comprising the alkyl-cyclohexanone, the alkyl-cyclohexanol, and water;

removing some of the water from the sixth stream to yield a seventh stream;

providing the seventh stream to a fourth distillation column to yield an eighth stream comprising the alkyl-cyclohexanone and the alkyl-cyclohexanol; and

providing the eighth stream to the second distillation column.

2. The method of claim 1 , wherein hydrogenating the alkyl-phenol occurs in the absence of a solvent.

3. The method of claim 1 , wherein hydrogenating the alkyl-phenol occurs in the presence of a solvent.

4. The method of claim 3 , wherein the solvent is selected from the group consisting of undecane, dodecane, and tridecane.

5. The method of claim 3 , wherein the solvent comprises dodecane.

6. The method of claim 3 , further comprising removing the solvent from the first distillation column.

7. The method of claim 6 , further comprising providing the solvent from the first distillation column to the first reactor.

8. The method of claim 1 , wherein the second stream further comprises an alkyl-cyclohexanol.

9. The method of claim 1 , further comprising removing unreacted alkyl-phenol from the first distillation column.

10. The method of claim 9 , further comprising providing the unreacted alkyl-phenol to the first reactor.

11. The method of claim 1 , wherein the fourth stream further comprises an alkyl-hydroxyhexanoic acid, an alkyl-adipic acid, or both.

12. The method of claim 1 , further comprising removing hydrogen from the first stream before providing the first stream to the first distillation column.

13. The method of claim 12 , wherein removing the hydrogen from the first stream comprises providing the first stream to a flash tank.

14. The method of claim 1 , wherein at least 80 wt % of the alkyl-phenol in the first reactor is converted to the alkyl-cyclohexanone.

15. The method of claim 1 , wherein less than 30 wt % of the purified alkyl-cyclohexanone is oxidized in the second reactor.

16. The method of claim 1 , wherein oxidizing the purified alkyl-cyclohexanone in the second reactor comprises providing an oxidizing agent to the second reactor.

17. The method of claim 16 , further comprising reacting substantially all of the oxidizing agent in the second reactor.

18. The method of claim 16 , wherein the oxidizing agent comprises hydrogen peroxide.

19. The method of claim 18 , wherein the oxidizing agent is provided as an aqueous solution comprising at least 40 wt % hydrogen peroxide.

20. The method of claim 1 , wherein the third distillation column is operated under sub-atmospheric pressure.

21. The method of claim 1 , further comprising providing the fifth stream to a fifth distillation column.

22. The method of claim 21 , wherein the fifth stream further comprises an alkyl-hydroxyhexanoic acid, an alkyl-adipic acid, or both.

23. The method of claim 21 , wherein the fifth distillation column is operated under sub-atmospheric pressure.

24. The method of claim 21 , wherein the fifth distillation column is operated below 5 atm.

25. The method of claim 1 , wherein the sixth stream undergoes heteroazeotropic distillation.

26. The method of claim 1 , wherein at least one of the second stream, the fourth stream, the sixth stream, and the eight stream comprises an alkyl-cyclohexanol.

27. The method of claim 1 , wherein the alkyl-phenol comprises one or more of:

wherein the alkyl (R) is selected from the group consisting of methyl, ethyl, propyl, and iso-propyl.

28. The method of claim 1 , wherein the alkyl-phenol comprises p-cresol.

29. The method of claim 1 , wherein the alkyl-phenol comprises a compound derived from lignin.

30. A method of synthesizing an alkyl-caprolactone, the method comprising:

(i) hydrogenating an alkyl-phenol in a trickle bed catalytic reactor to yield a first mixture comprising an alkyl-cyclohexanone and an alkyl-cyclohexanol;

(ii) separating the alkyl-cyclohexanone from the first mixture to yield a first portion of a purified alkyl-cyclohexanone;

(iii) oxidizing the first portion of the purified alkyl-cyclohexanone in a liquid phase fixed bed oxidation reactor to yield a second mixture comprising an alkyl-caprolactone, the alkyl-cyclohexanone, and the alkyl-cyclohexanol;

(iv) separating the alkyl-caprolactone from the second mixture to yield a third mixture comprising the alkyl-cyclohexanone and the alkyl-cyclohexanol;

(v) combining the third mixture and the first mixture in (i) to yield a fourth mixture;

(vi) separating the alkyl-cyclohexanone from the fourth mixture to yield a second portion of the purified alkyl-cyclohexanone;

(vii) oxidizing the second portion of the purified alkyl-cyclohexanone in a liquid phase fixed bed oxidation reactor to yield a fifth mixture comprising the alkyl-caprolactone, the alkyl-cyclohexanone, and the alkyl-cyclohexanol;

(viii) separating the alkyl-caprolactone from the fifth mixture; and

(ix) combining the alkyl-caprolactone from the fifth mixture with the alkyl-caprolactone from the second mixture.