Synthesis of 7-acetyleno quinone methide derivatives and their application as vinylic polymerization retarders
The invention provides a method for synthesizing 7-Acetyleno quinone methide compounds that is safe and inexpensive. The method avoids the need for extremely cold reaction temperatures and unlike the prior art does not require any highly explosive materials. The method comprises the steps of: a) performing a condensation reaction between 3,5-di-tert-butyl-4-hydroxybenzaldehyde and a secondary amine thereby forming a secondary amine quinone methide intermediate; b) removing water from the secondary amine quinone methide intermediate by azeotropic distillation; c) adding the dehydrated secondary amine quinone methide intermediate to an organic medium containing a metal acetylide to form a Mannich base intermediate; and d) adding a release agent to the Mannich base intermediate to yield a 7-Acetyleno quinone methide.
1. A method for the synthesis of 7-Acetyleno quinone methides, the method comprising the steps of:
a) performing a condensation reaction between a 3,5-di-substituted-4-hydroxybenzaldehyde and a secondary amine thereby forming a secondary amine quinone methide intermediate;
b) removing water from the secondary amine quinone methide intermediate in a high boiling point hydrocarbon solvent by azeotropic distillation at a temperature of between 100 and 160° C., said hydrocarbon solvent being one from the group consisting of an aliphatic solvent, an aromatic solvent, and any combination thereof;
c) adding the dehydrated secondary amine quinone methide intermediate to an organic medium containing a metal acetylide to form a Mannich base intermediate, and
d) adding a release agent to the Mannich base intermediate to yield a 7-Acetyleno quinone methide.
2. The method of claim 1 in which the 3,5-di-substituted-4-hydroxybenzaldehyde has the following formula:
where R 1 and R 2 are independently selected from C 4 -C 18 alkyl, C 5 -C 12 cycloalkyl, phenyl and C 7 -C 15 phenylalkyl.
3. The method of claim 1 in which the secondary amine is at least one of the group consisting of: a 5-membered heterocyclic group and/or a 6-membered heterocyclic group with the following structures, respectively:
where X is one selected from CH 2 , O, S, or NR 4 , where R 4 is one selected from C 1 -C 18 alkyl, C 5 -C 12 cycloalkyl, phenyl, and C 7 -C 15 phenylalkyl.
4. The method of claim 1 in which the secondary amine quinone methide intermediate is a 4-((N,N-disubstitutedamino)methylene)cyclohexa-2,5-dienone quinone methide molecule with the following structural formula:
where each of R 1 and R 2 are each one item selected from the list of: C 4 -C 18 alkyl, C 5 -C 12 cycloalkyl, phenyl, C 7 -C 15 phenylalkyl, and any combination thereof, and R 5 is selected from the group consisting of tert-butyl, tert-amyl, tert-octyl, cyclohexyl, α-methylbenzyl or α,α-dimethylbenzyl.
5. The method of claim 1 in which the secondary amine quinone methide intermediate is a 4-((N,N-disubstitutedamino)methylene)cyclohexa-2,5-dienone quinone methide molecule with the following structural formula:
where each of R 1 and R 2 are each one item selected from the list of: C 4 -C 18 alkyl, C 5 -C 12 cycloalkyl, phenyl, C 7 -C 15 phenylalkyl, and any combination thereof, and R 5 is a N,N-disubstitutedamino group or a 5-membered or 6-membered heterocyclic groups with the following structures:
where X is CH 2 , O, S, NR 4 , C 1 -C 18 alkyl, C 5 -C 12 cycloalkyl, phenyl, C 7 -C 15 phenylalkyl, and any combination thereof.
6. The method in claim 1 whereby the Mannich base intermediate has the following molecular formula:
where R 1 and R 2 are independently selected from C 4 -C 18 alkyl, C 5 -C 12 cycloalkyl, phenyl, C 7 -C 15 phenylalkyl, and R 6 is one item selected from: H, C 1 -C 18 alkyl, C 5 - C 12 cycloalkyl, phenyl, C 7 -C 15 phenylalkyl, substituted phenyl group -Ph-R 7 , and Z is a secondary N,N-disubstitutedamino group and/or a 5-membered or 6-membered heterocyclic groups with the following structures:
in which X is CH2, O, S, and NR4, and any combination thereof, and R4 is selected from C1-C18 alkyl, C5-C12 cycloalkyl, phenyl, and C7-C15 phenylalkyl.
7. The method of claim 6 in which R 1 and R 2 are selected from: tert-butyl, tert-amyl, tert-octyl, cyclohexyl, α-methylbenzyl, α,α-dimethylbenzyl, and any combination thereof.
8. The method of claim 6 in which R 6 is selected from: H, C 1 -C 18 alkyl, C 5 -C 12 cycloalkyl, phenyl, C 7 -C 15 phenylalkyl, substituted phenyl group -Ph-R 7 , and any combination thereof, and preferably R 7 is —COOH, and —COOR 8 in which R 8 is independently selected from C 1 -C 18 alkyl, C 5 -C 12 cycloalkyl, phenyl and C 7 -C 15 phenylalkyl.
9. The method in claim 6 in which Z is a a 5-membered or 6-membered heterocyclic groups with the following structures:
and any combination thereof.
10. The method of claim 9 in which X is O.
11. The method of claim 9 in which Z is selected from the group consisting of a 5-membered heterocyclic group and a 6-membered heterocyclic group in which X is CH 2 and O, and any combination thereof.
12. The method of claim 1 in which the release agent is an acid and/or p-toluenesulfonic acid.
13. A method for the synthesis of 7-Acetyleno quinone methides, the method comprising the steps of:
a) performing a condensation reaction between a 3,5-di-substituted-4-hydroxybenzaldehyde and a secondary amine thereby forming a secondary amine quinone methide intermediate;
b) removing water from the secondary amine quinone methide intermediate in a high boiling point hydrocarbon solvent by azeotropic distillation at a temperature of between 100 and 160° C.;
c) adding the dehydrated secondary amine quinone methide intermediate to an organic medium containing a metal acetylide to form a Mannich base intermediate, and
d) adding a release agent to the Mannich base intermediate to yield a 7-Acetyleno quinone methide.