Methods of making intermediates from polyhydroxyalkanoates
Methods of forming intermediates from PHAs are disclosed.
1. A method of making a diol from a PHA, comprising:
hydrogenolyzing a PHA to form a diol, wherein the PHA contains at least about 500 monomer units, and the monomer units are selected from the group consisting of 3-hydroxypropionate, 4-hydroxybutyrate, 4-hydroxypentanoate, 5-hydroxypentanoate, and combinations thereof.
2. The method of claim 1 , wherein the PHA is hydrogenolyzed at a temperature of at least about 100° C.
3. The method of claim 1 , wherein the percent yield of diol from the PHA is at least about five percent.
4. The method of claim 1 , wherein the PHA is a chiral PHA, and a percent chirality yield of chiral diol is at least about five percent.
5. The method of claim 1 , wherein hydrogenolysis occurs in the presence of a hydrogen-containing gas.
6. The method of claim 5 , wherein the hydrogen-containing gas comprises hydrogen gas.
7. The method of claim 1 , wherein the PHA is derived from a biomass.
8. The method of claim 7 , wherein the biomass is selected from the group consisting of plant biomass and microbial biomass.
9. The method of claim 7 , wherein the biomass is non-lyophilized.
10. The method of claim 7 , wherein less than about 50 weight percent of the PHA that is treated to form the diol is removed from the biomass before being treated to form the diol.
11. The method of claim 1 , further comprising contacting the PHA with a reducing agent during hydrogenolysis.
12. The method of claim 1 , further comprising contacting the PHA with a catalyst during hydrogenolysis.
13. The method of claim 1 , further comprising combining the PHA with a solvent.
14. The method of claim 1 , wherein the diol has the structure:
and wherein n is selected from the group consisting of zero and an integer greater than zero, and each of R 1 , R 2 , R 3 , R 4 , R 5 and R 6 is independently selected from the group consisting of a hydrogen atom, a halogen atom and a hydrocarbon radical.
15. The method of claim 14 , wherein n is zero, one or two.
16. The method of claim 15 , wherein R 2 , R 3 and R 4 are each hydrogen atoms.
17. The method of claim 16 , wherein R 1 is selected from the group consisting of a hydrogen atom, a methyl radical, an ethyl radical, a propyl radical, a butyl radical and a pentyl radical.
18. The method of claim 1 , wherein the PHA is selected from the group consisting of poly 3-hydroxypropionate, poly 4-hydroxybutyrate, poly 4-hydroxypentanoate, and poly 5-hydroxypentanoate.
19. The method of claim 1 , wherein the diol is selected from the group consisting of 1,4-butanediol, 1,3-propanediol, 1,4-pentanediol, 1,5-pentanediol, 3-butanediol, 1,3-pentanediol, 1,3-hexanediol, 1,3-octanediol and 1,2-propanediol.
20. The method of claim 1 , wherein the PHA is contacted with the transition metal catalyst in the substantial absence of a halogenated solvent.
21. The method of claim 1 , wherein the diol is formed without first forming a hydroxy acid.
22. The method of claim 1 , wherein the diol contains only one monomer unit from the PHA.
23. The method of claim 13 , wherein the solvent comprises an alcohol.
24. The method of claim 23 , wherein the alcohol comprises a diol.
25. The method of claim 24 , wherein the diol comprises the same diol as formed by treating the PHA.
26. The method of claim 24 , further comprising reacting the diol to form a cyclic ether.
27. The method of claim 26 , wherein the cyclic ether comprises polyether polyol.