Porous polymer compositions for the synthesis of monolithic bimodal microporous/macroporous carbon compositions useful for selective CO2 sequestration
The present invention discloses novel porous polymeric compositions comprising random copolymers of amides, imides, ureas, and carbamic-anhydrides, useful for the synthesis of monolithic bimodal microporous/macroporous carbon aerogels. It also discloses methods for producing said microporous/macroporous carbon aerogels by the reaction of a polyisocyanate compound and a polycarboxylic acid compound, followed by pyrolytic carbonization, and by reactive etching with CO 2 at elevated temperatures. Also disclosed are methods for using the microporous/macroporous carbon aerogels in the selective capture and sequestration of carbon dioxide.
1. A porous co-polymeric composition comprising gels and/or aerogels:
said composition obtained by mixing together one or more polyisocyanate compounds and one or more polycarboxylic acid compounds at room temperature in a solvent;
wherein the polyisocyanate compound includes at least 2 isocyanate functional groups, and wherein the polycarboxylic acid compound includes at least 3 carboxylic acid functional groups at least 2 of which are positioned relative to each other in such a manner so as to be able to form an intramolecular anhydride;
said composition including at least an amide linkage, an imide linkage and a urea linkage present in any random order.
2. The composition of claim 1 wherein the one or more polyisocyanate compound is a compound of the formula (II) and the one or more polycarboxylic acid compound is a compound of the formula (III):
G1-(NCO)q
G2-(COOH)r
(II)
(III)
wherein:
G1 is a moiety selected from C1-C10 straight chain alkyl or branched alkyl or cycloalkyl, alkylaryl, aryl, heteroalkyl, heterocyclylalkyl, or heteroaryl, each of which is optionally substituted;
G2 is a moiety selected from alkyl, cycloalkyl, heteroalkyl, heterocylcoalkyl, alkylaryl, cycloalkylaryl, alkylheteroaryl, cycloalkylheteroaryl, an arene ring system, or a heteroarene ring system, each of which is optionally substituted;
q=2-6; and,
r=3-8.
3. The composition of claim 1 , wherein the one or more polyisocyanate compound and the one or more polycarboxylic acid compound are mixed together in such amounts so that the ratio of isocyanate functional groups to carboxylic acid functional groups is about 1:1.
4. The composition of claim 1 , wherein the one or more polyisocyanate compound is selected from the following compounds:
5. The composition of claim 1 , wherein the one or more polycarboxylic acid compound is selected from the following compounds, or is derivable from its respective anhydride shown:
6. The composition of claim 1 , wherein the solvent is a single solvent or a mixture of solvents, including ether-type solvents, ester-type solvents, amide-type solvents, ketone-type solvents, nitrile-type solvents, or mixtures of any of the foregoing solvents.
7. The composition of claim 2 , wherein the one or more polyisocyanate compound is a compound of the formula (IV) and the one or more polycarboxylic acid compound is a compound of the formula (V):
wherein the isocyanate groups of compound (IV) are independently attached to their respective aryl rings at the 2, 3, or 4-positions of the aryl rings;
wherein R1, R2, R3, and R4 are independently one or more substituents selected from H, alkyl, cycloalkyl, alkoxy, alkylthio, aryl, aryloxy, arylthio, each of which is optionally substituted, and halogen, nitro, or cyano.
8. The composition of claim 7 , wherein the composition has the formula (VI):
wherein W1, W2, W3, W4, W5, and W6 represent linking moieties selected from an amide group, a urea group, an imide group, a carbamic-anhydride group, and/or any combinations thereof; and,
n is an integer ranging from 2 to about 500.
9. The composition of claim 8 , wherein R1, R2, R3, and R4 are H; and,
wherein the isocyanate groups of the polyisocyanate compound (IV) are attached to their respective aryl rings at the 4-positions of the aryl rings.
10. The composition of claim 1 , further including a carbamic-anhydride linkage.