Humic acid derivatives and methods of preparation and use
Disclosed are antioxidative natural compounds, their salts, chelates and cleavage derivatives that exhibit a superior combination of properties. The compounds can be used for a variety of purposes, including the stabilization of polymers. The compounds can be prepared by substantially cleaving a humic acid of formula I followed by esterification to provide at least one antioxidant compounds of formula V, formula VI, formula VII, formula VIII, salts thereof, or chelates thereof.
1. A stabilizing compound comprising at least one humic acid derivative, wherein the humic acid derivative is selected from the group consisting of formula VI, formula VII, and formula VIII:
R 2 is hydrogen, —(C 1 -C 20 )alkyl, or substituted —(C 1 -C 20 )alkyl;
R 4 is hydrogen, —(C 1 -C 20 )alkyl, or substituted —(C 1 -C 20 )alkyl;
R 21 , R 22 , R 31 , R 32 , and R 41 are independently hydrogen, —(C 4 -C 20 )alkyl, or substituted —(C 4 -C 20 )alkyl;
R 23 , R 24 , R 25 , R 26 , R 27 , R 33 , R 34 , R 35 , R 36 , R 42 , R 43 , and R 44 are independently hydrogen, —(C═O)—(C 3 -C 19 )alkyl, or substituted —(C═O)—(C 3 -C 19 )alkyl; and
wherein at least one of R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , and R 27 is not hydrogen; at least one of R 31 , R 32 , R 33 , R 34 , R 35 , and R 36 is not hydrogen; and at least one of R 41 , R 42 , R 43 , and R 44 is not hydrogen;
a salt, a chelate, or a combination thereof.
2. The compound of claim 1 , wherein the humic acid derivative of formula VI, formula VII, formula VIII, a salt, a chelate, or a combination thereof comprises:
R 2 is hydrogen or —(C 1 -C 20 )alkyl;
R 23 , R 24 , R 25 , R 26 , and R 27 , are independently hydrogen or —(C═O)—(C 3 -C 19 )alkyl;
R 4 is hydrogen or —(C 1 -C 20 )alkyl;
R 41 is independently hydrogen or —(C 4 -C 20 )alkyl; and
R 42 , R 43 , and R 44 are independently hydrogen or —(C═O)—(C 3 -C 19 )alkyl, wherein at least one of R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 41 , R 42 , R 43 , and R 44 is not hydrogen.
3. The compound of claim 1 , wherein the humic acid derivative comprises formula VI, a salt thereof, or a chelate thereof.
4. The compound of claim 1 , wherein R 2 is methyl.
5. The compound of claim 1 , wherein R 21 R 22 , are independently hydrogen or —(C 4 -C 20 )alkyl.
6. The compound of claim 1 , wherein R 23 , R 24 , R 25 , R 26 , and R 27 , are independently hydrogen or —(C═O)—(C 3 -C 19 )alkyl; and wherein at least one of R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , and R 27 is not hydrogen.
7. The compound of claim 1 , wherein the humic acid derivative is formula VII, a salt thereof, or a chelate thereof.
8. The compound of claim 1 , wherein the humic acid derivative is formula VIII, a salt thereof, or a chelate thereof.
9. The compound of claim 1 , wherein the salt is selected from the group consisting of a lithium salt, a sodium salt, an ammonium salt, a potassium salt, a calcium salt, a barium salt, a magnesium salt, a manganese salt, a zinc salt, an aluminum salt, and an iron salt.
10. The compound of claim 1 , wherein the humic acid derivative is a polyvalent cation chelate.
11. The compounds of claim 1 , wherein the humic acid derivative is independently a calcium chelate, a magnesium chelate, an iron chelate, a zinc chelate or a combination thereof.
12. A method of preparing a polymer stabilizing mixture of compounds, the method comprising:
substantially hydrolyzing a humic acid to form a mixture of compounds according to formula VI, formula VII and formula VIII, a salt, a chelate, or a combination thereof:
wherein:
R 2 is hydrogen, —(C 1 -C 20 )alkyl, or substituted —(C 1 -C 20 )alkyl;
R 4 is hydrogen, —(C 1 -C 20 )alkyl, or substituted —(C 1 -C 20 )alkyl;
R 21 , R 22 , R 31 , R 32 , and R 41 are independently hydrogen, —(C 4 -C 20 )alkyl, or substituted —(C 4 -C 20 )alkyl;
R 23 , R 24 , R 25 , R 26 , R 27 , R 33 , R 34 , R 35 , R 36 , R 42 , R 43 , and R 44 are independently hydrogen, —(C═O)—(C 3 -C 19 )alkyl, or substituted —(C═O)—(C 3 -C 19 )alkyl;
wherein at least one of R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , and R 27 is not hydrogen; at least one of R 31 , R 32 , R 33 , R 34 , R 35 , and R 36 is not hydrogen; and at least one of R 41 , R 42 , R 43 , and R 44 is not hydrogen; and
esterifying at least one functional group of the mixture of compounds to give a polymer stabilizing mixture of compounds.
13. The method of claim 12 , wherein esterifying comprises forming a alkyl ester of at least one of R 23 , R 24 , R 25 , R 26 , R 27 , R 33 , R 34 , R 35 , R 36 , R 42 , R 43 , and R 44 , to give an esterified mixture.
14. The method of claim 12 , wherein esterifying comprises forming a (C 4 -C 20 )alkyl ester of at least one of R 21 , R 22 , R 31 , R 32 , and R 41 , to give an esterified mixture.
15. The method of claim 12 , further comprising forming a chelate of at least one compound of the polymer stabilizing mixture with a calcium cation, a magnesium cation, a zinc cation, an iron cation, or a combination thereof.
16. The method of claim 12 , further comprising forming a salt of at least one compound of the polymer stabilizing mixture to form a lithium salt, a sodium salt, an ammonium salt, a potassium salt, a calcium salt, a barium salt, a magnesium salt, a manganese salt, a zinc salt, an aluminum salt, an iron salt, or a combination thereof.
17. The method of claim 12 , further comprising purifying at least one compound of the polymer stabilizing mixture.
18. The method of claim 12 , further comprising isolating a compound of the polymer stabilizing mixture of formula VI, wherein at least one of R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , and R 27 is not hydrogen.
19. The method of claim 12 , further comprising isolating a compound of the polymer stabilizing mixture of formula VII, wherein at least one of R 31 , R 32 , R 33 , R 34 , R 35 , and R 36 is not hydrogen.
20. The method of claim 12 , further comprising isolating a compound of the polymer stabilizing mixture of formula VIII, wherein at least one of R 41 , R 42 , R 43 , and R 44 is not hydrogen.
21. The method of claim 12 , wherein the hydrolyzing comprises hydrolyzing in the presence of an alkaline solution.
22. The method of claim 21 , wherein the alkaline solution is aqueous lithium hydroxide, aqueous sodium hydroxide, aqueous potassium hydroxide, or a combination thereof.
23. The method of claim 12 , wherein the hydrolyzing comprises hydrolyzing at a pH of 8.5-13.