Processes for preparing calixarenes
This invention relates to a process for preparing a calixarene compound by reacting a phenolic compound and an aldehyde in the presence of at least one nitrogen-containing base as a catalyst to form the calixarene compound. The invention also relates to processes for high-yield, high solid-content production of a calixarene compound, with high selectivity toward a high-purity calix[8]arene compound, without carrying out a recrystallization step.
1. A process for preparing a calixarene compound, comprising:
reacting a phenolic compound and an aldehyde in the presence of at least one nitrogen-containing base as a catalyst to form the calixarene compound, wherein the nitrogen-containing base is a tetraalkyl ammonium hydroxide, wherein each alkyl moiety in the tetraalkyl ammonium hydroxide is independently C 1 to C 2 alkyl.
2. The process of claim 1 , wherein the tetraalkyl ammonium hydroxide is tetramethyl ammonium hydroxide.
3. The process of claim 1 , wherein the tetraalkyl ammonium hydroxide is tetraethyl ammonium hydroxide.
4. The process of claim 1 , wherein the phenolic compound is phenol, an alkyl phenol, or an arylalkyl phenol.
5. The process of claim 4 , wherein the phenolic compound is a para-C 1 -C 24 alkyl phenol, benzyl phenol, or cumyl phenol.
6. The process of claim 1 , wherein the aldehyde is formaldehyde or paraformaldehyde.
7. The process of claim 1 , wherein the molar ratio of the phenolic compound to the aldehyde ranges from about 1:1.5 to about 1.5:1, and the molar ratio of the phenolic compound to the nitrogen-containing base ranges from about 200:1 to about 20:1.
8. The process of claim 1 , wherein the reaction is carried out in the presence of an organic solvent.
9. The process of claim 8 , wherein the mass ratio of the phenolic compound to the organic solvent is no less than 0.25:1.
10. The process of claim 1 , wherein the reaction is carried out under reflux conditions.
11. The process of claim 1 , wherein the aldehyde is paraformaldehyde and the reaction is carried out without reflux.
12. A one-step process for preparing a calixarene compound, comprising:
reacting a phenolic compound and an aldehyde in the presence of at least one nitrogen-containing base as a catalyst to form the calixarene compound in a one-step process, wherein the nitrogen-containing base is a tetraalkyl ammonium hydroxide, wherein each alkyl moiety in the tetraalkyl ammonium hydroxide is independently C 1 to C 6 alkyl.
13. The process of claim 12 , wherein the phenolic compound is phenol, an alkyl phenol, or an arylalkyl phenol.
14. The process of claim 13 , wherein the phenolic compound is a para-C 1 -C 24 alkyl phenol, benzyl phenol, or cumyl phenol.
15. The process of claim 12 , wherein the aldehyde is formaldehyde or paraformaldehyde.
16. The process of claim 12 , wherein the molar ratio of the phenolic compound to the aldehyde ranges from about 1:1.5 to about 1.5:1, and the molar ratio of the phenolic compound to the nitrogen-containing base ranges from about 200:1 to about 20:1.
17. The process of claim 12 , wherein the reaction is carried out in the presence of an organic solvent.
18. The process of claim 17 , wherein the mass ratio of the phenolic compound to the organic solvent is no less than 0.25:1.
19. The process of claim 12 , wherein the reaction is carried out under reflux conditions.
20. The process of claim 12 , wherein the aldehyde is paraformaldehyde and the reaction is carried out without reflux.