High density polymers based on norbornadiene
View Patent ↗A novel family of cycloalkanes compounds having one or more allylidene functionalities which can be used to create cross-linked thermosets and thermoplastics having thermal stability. An example heptacyclo [6.6.0.0 2,6 .0 3,13 .0 4,11 .0 5,9 .0 10,14 ] tetradecane (HCTD) complex with terminal allylidene groups at the 7- and 12-positions (HCTD-7,12-diallylidene) was generated from norbornadiene via an efficient six-step synthesis. Thermal polymerization at temperatures ranging from 160 to 240° C. yielded a robust cross-linked material with thermal stability up to 485° C. in air, a glass transition temperature of 377° C., and a char yield (600° C.) of 56% in air. Applications include heat resistant composites utilized in the aerospace, electronic, automotive and textile industries.
1. A resin comprising a polymer containing units derived from cycloalkanes having one or more allylidene functionalities.
2. The resin of claim 1 which is thermoplastic.
3. The resin of claim 1 which is a thermoset.
4. The resin of claim 1 wherein said cycloalkanes are derived from norbornadiene.
5. The resin of claim 1 wherein said cycloalkanes are comprised of heptacyclotetradecane-7, 12-diallylidene.
6. A high density hydrocarbon network comprising the resin of claim 1 .
7. The high density hydrocarbon network of claim 6 having a density exceeding about 1.2 g/mL.
8. A high density hydrocarbon network comprising a polymer containing units derived from cycloalkanes having one or more allylidene functionalities and having a density exceeding about 1.2 g/mL.
9. A process for the preparation of a cycloalkane having one or more allylidene functionalities, comprising:
functionalizing norbornadiene with an alkoxide (—OR) at the 7-position,
wherein R is methyl, ethyl, propyl, tert-butyl, or isopropyl to form a functionalized norbornadiene;
converting the functionalized norbornadiene to a norbornadiene dimer cage structure with alkoxides at the 7- and 12-positions;
converting the alkoxides of the norbornadiene dimer cage structure to alcohols;
oxidizing the alcohols to ketones;
functionalizing the ketones with an alkylating agent to form tertiary alcohols;
dehydrating the tertiary alcohols to generate the cycloalkane having one or more allylidene functionalities.
10. The process of claim 9 wherein the functionalized norbornadiene is converted to a norbornadiene dimer cage structure with a transition metal catalyst selected from metal carbonyl, ruthenium-based catalysts, or a catalyst capable of performing a [4+4]cycloaddition.
11. The process of claim 9 wherein the alkoxides at the 7- and 12-positions are reduced to alcohols in the presence of a base, and a reagent SiR3-X, where R is an alkyl group and X is Cl, Br, or I.
12. The process of claim 11 wherein a reduction reaction is quenched with a basic alcohol solution containing an alkali bicarbonate, and an alcohol selected from methanol, ethanol, isopropyl alcohol, n-butanol, or tert-butanol.
13. The process of claim 9 wherein the alcohols are oxidized to ketones by exposure to a strong oxidant.
14. The process of claim 13 wherein the strong oxidant is chromic acid, sodium dichromate, pyridinium chlorochromate, potassium permanganate, or copper oxide.
15. The process of claim 9 wherein the alkylating reagent comprises an organolithium, Gilman reagent, organotin, or Grignard reagent.
16. The process of claim 9 wherein dehydrating the tertiary alcohols is performed with a selective reducing agent.
17. The process of claim 9 , further comprising polymerizing the cycloalkane having one or more allylidene functionalities.
18. The process of claim 17 further comprising cross-linking resulting polymers.