Processes for preparing calixarenes

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 phenolic compound is para-nonylphenol (PNP) or para-dodecylphenol (PDDP), and

wherein the process produces a calixarene-containing product having at least 45% solids.

2. The process of claim 1 , wherein the process produces a calixarene-containing product having at least 50% solids.

3. The process of claim 1 , 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.

4. The process of claim 3 , wherein the tetraalkyl ammonium hydroxide is tetramethyl ammonium hydroxide.

5. The process of claim 1 , wherein the nitrogen-containing base is an amidine compound having the formula of

wherein R 1 , R 2 , R 3 , and R 4 are each independently H, alkyl, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl; or any two or more of R 1 , R 2 , R 3 , and R 4 can be bonded together to form a five- to nine-membered ring structure.

6. The process of claim 5 , wherein the amidine compound is selected from the group consisting of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), 1,2-dimethyl-1,4,5,6-tetrahydropyrimidine, 1-ethyl-2-methyl-1,4,5,6-tetrahydropyrimidine, 1,2-diethyl-1,4,5,6-tetrahydropyrimidine, 1-n-propyl-2-methyl-1,4,5,6-tetrahydropyrimidine, 1-isopropyl-2-methyl-1,4,5,6-tetrahydropyrimidine, 1-ethyl-2-n-propyl-1,4,5,6-tetrahydropyrimidine, and 1-ethyl-2-isopropyl-1,4,5,6-tetrahydropyrimidine.

7. The process of claim 6 , wherein the amidine compound is DBU.

8. The process of claim 1 , wherein the aldehyde is formaldehyde or paraformaldehyde.

9. The process of claim 8 , wherein the aldehyde is paraformaldehyde.

10. The process of claim 1 , wherein the phenolic compound is PNP.

11. The process of claim 1 , wherein the phenolic compound is PDDP.

12. The process of claim 1 , wherein the PNP compound or the PDDP compound primarily contains the para isomer of the compound.

13. The process of claim 1 , wherein the source of the phenolic compound is either PNP or PDDP.

14. 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.

15. The process of claim 1 , wherein the reaction is carried out in the presence of an organic solvent.

16. The process of claim 15 , wherein the organic solvent is a mixture further containing an aromatic hydrocarbon.

17. The process of claim 15 , wherein the organic solvent is a mixture further containing a straight-chain C 11 to C 20 hydrocarbon.

18. The process of claim 15 , wherein the mass ratio of the phenolic compound and the organic solvent is no less than 0.5:1.

19. The process of claim 1 , wherein the reaction is carried out under reflux conditions.

20. The process of claim 1 , wherein the aldehyde is paraformaldehyde and the reaction is carried out without reflux.

21. A phenolic oligomer composition prepared by the process of claim 1 .

22. The process of claim 11 , wherein the aldehyde is aqueous formaldehyde and the reaction is carried out with a reflux stage.

23. The process of claim 22 , wherein, at the reflux stage, the reaction is heated at a temperature higher than the temperature needed for reaching a reflux, to reduce the reaction time at the reflux stage.

24. The process of claim 23 , wherein at the reflux stage, the reaction is heated at a temperature about 5-20° C. higher than the temperature needed for reaching a reflux, to reduce the reaction time about 50% of the reaction time typically needed for the reflux stage.

25. The process of claim 22 , wherein at the reflux stage, the reaction is heated under pressure, to reduce the reaction time at the reflux stage.