Synthesis of a highly crystalline, covalently linked porous network
Porous networks are described linked by boronates. Also described are processes for producing the porous networks. The porous networks are formed by reacting a polyboronic acid with itself or with a polydiol, a polydiamine, or a polyamino alcohol. The resulting boronate linkage is covalently bonded. The characteristics and properties of the resulting porous material can be varied and altered by changing the reactants and by incorporating functional groups into the reactants. Of particular advantage, the porous materials can be formed at or near atmospheric pressure and at low temperature in the presence of one or more solvents.
1. A process for forming a boronate linked porous network comprising:
reacting a polyboronic acid or an acyclic boronate ester thereof with a polydiol, a polyamino alcohol, or a polydiamine to form a covalently bonded polymeric or oligomeric porous network linked via boronate linkages, wherein the reaction occurs at or near atmospheric pressure in the presence of a first solvent and a second solvent, the first solvent comprising an alcohol, the second solvent having a boiling point less than about 110° C., and wherein the reaction occurs at a temperature from about 15° C. to about 110° C.
2. A process as defined in claim 1 , wherein the polyboronic acid or acyclic boronate ester thereof comprises a triboronic acid or an acyclic boronate ester thereof.
3. A process as defined in claim 2 , wherein the polydiol comprises a bis-diol.
4. A process as defined in claim 2 , wherein the polydiol comprises 1,2,4,5-tetrahydroxybenzene.
5. A process as defined in claim 2 , wherein the triboronic acid or acyclic boronate ester thereof comprises benzene-1,3,5-triboronic acid or an acyclic boronate ester thereof.
6. A process as defined in claim 1 , wherein the resulting porous network comprises stacked sheets of the boronate, each sheet defining a pattern of pores, and wherein pores on adjacent sheets are in alignment, and wherein pores contained within the porous network have a diameter of less than about 200 angstroms, the porous network of boronate ester being thermally stable to a temperature of at least 500° C. and having a surface area of at least about 400 m 2 /g.
7. A process as defined in claim 1 , wherein the polydiol comprises
or mixtures thereof.
8. A process as defined in claim 1 , wherein the polyboronic acid or acyclic boronate ester thereof comprises
or an acyclic boronate ester thereof.
9. A process as defined in claim 1 , wherein the polyboronic acid or acyclic boronate ester thereof is reacted with a polyamino alcohol or a polydiamine.
10. A process as defined in claim 9 , wherein the polyamino alcohol or the polydiamine comprises
or mixtures thereof.
11. A process as defined in claim 1 , wherein a first reactant comprises the polyboronic acid or the acyclic boronate ester thereof and wherein a second reactant comprises a polydiol, a polyamino alcohol, or a polydiamine in order to form the boronate-linked porous network, and wherein at least the first reactant or the second reactant contains a functional group that becomes incorporated into the network, the functional group being located within the pores defined by the porous network, the functional group comprising an acid, an ester, an amide, a halogen, an ether, an alkyl, a silyl, a nitrile, an amine, an alcohol or a thiol.
12. A process as defined in claim 11 , wherein the first reactant or the second reactant comprises
and wherein at least one of R 1 , R 2 , R 3 or R 4 comprises the functional group.
13. A process as defined in claim 1 , wherein the second solvent comprises tetrahydrofuran.
14. A process as defined in claim 1 , wherein the reaction occurs in the presence of excess polydiol.
15. A process as defined in claim 1 , wherein the resulting porous network contains pores having a pore diameter of less than about 20 angstroms.
16. A process as defined in claim 1 , wherein the resulting porous network comprises stacked sheets of the boronate ester, each sheet defining a pattern of pores.
17. A process as defined in claim 1 , wherein the resulting porous network is thermally stable at a temperature of at least 500° C. and has a surface area of at least 400 m 2 /g.
18. A process as defined in claim 1 , wherein the boiling point of the second solvent is less than about 100° C.
19. A process as defined in claim 1 , wherein the first solvent comprises methanol, ethanol, propanol, or mixtures thereof.
20. A process as defined in claim 1 , wherein the first solvent comprises methanol.
21. A process as defined in claim 1 , wherein the reaction occurs at a temperature from about 20° C. to about 90° C.
22. A process for forming a boronate linked porous network comprising:
reacting a polyboronic acid or an acyclic boronate ester thereof with a polyamino alcohol or a polydiamine to form a covalently bonded polymeric or oligomeric porous network linked via boronate linkages, wherein the reaction occurs at or near atmospheric pressure, and wherein the reaction occurs at a temperature from about 15° C. to about 110° C.
23. A process as defined in claim 22 , wherein the polyamino alcohol or the polydiamine comprises
or mixtures thereof.
24. A process as defined in claim 22 , wherein the polyboronic acid or acyclic boronate ester thereof comprises a triboronic acid or an acyclic boronate ester thereof.
25. A process as defined in claim 22 , wherein the resulting porous network contains pores having a pore diameter of less than about 20 angstroms.
26. A process as defined in claim 22 , wherein the reaction is performed in the presence of a first solvent and a second solvent.
27. A process as defined in claim 26 , wherein the first solvent comprises an alcohol.
28. A process as defined in claim 26 , wherein the first solvent comprises methanol, ethanol, propanol, or mixtures thereof.
29. A process as defined in claim 26 , wherein the first solvent comprises methanol.
30. A process as defined in claim 26 , wherein the boiling point of the second solvent is less than about 110° C.
31. A process as defined in claim 26 , wherein the boiling point of the second solvent is less than about 100° C.
32. A process as defined in claim 26 , wherein the second solvent comprises tetrahydrofuran.
33. A process as defined in claim 22 , wherein the reaction occurs at a temperature from about 20° C. to about 90° C.