Process for preparing phenols
View Patent ↗The present invention relates to a process for preparing phenols by adding an aqueous base to the reaction product from the acid-catalyzed cleavage of alkylaryl hydroperoxides while maintaining a homogeneous phase prior to the work-up of the product.
1. A method for preparing phenols comprising:
adding an aqueous base to a reaction product from an acid-catalyzed cleavage of alkylaryl hydroperoxides while maintaining a homogeneous phase prior to work-up of the product, and
introducing an oxygen-containing gas into the reaction product.
2. The method of claim 1 , wherein the aqueous base is selected from the group consisting of aqueous NaOH and aqueous phenoxide solutions.
3. The method of claim 2 , wherein the aqueous base is an aqueous phenoxide solution recovered from at least one working-up stage of the process for preparing phenols.
4. The method of claim 2 , wherein the phenoxide is sodium phenolate, and wherein the aqueous sodium phenolate solution or the aqueous NaOH solution is added to the reaction product in a concentration and amount to result in an sodium phenolate concentration in the homogeneous phase of 0.2 to 2.5 wt.-%.
5. The method of claim 4 , wherein the sodium phenolate concentration in the homogeneous phase is between 0.5 and 1 wt.-%.
6. The method of claim 1 , further comprising adjusting the temperature of the homogeneous phase after addition of the aqueous base to a temperature in the range of 20° C. to 150° C.
7. The method of claim 6 , wherein said temperature is in the range of 60° C. to 120° C.
8. The method of claim 6 , wherein said temperature is in the range of 80° C. to less than 100° C.
9. The method of claim 1 , wherein the reaction product is saturated with the oxygen-containing gas.
10. The method of claim 1 , wherein the oxygen-containing gas is pressurized.
11. The method of claim 1 , wherein the oxygen-containing gas is selected from the group consisting of oxygen and air.
12. The method of claim 1 , wherein the homogeneous phase comprising the reaction product and the aqueous base is maintained in a residence time vessel prior to work-up of the product.
13. The method of claim 12 , wherein the residence time is between about 10 and about 7200 seconds.
14. The method of claim 1 , wherein the alkylaryl hydroperoxide is cumene hydroperoxide.
15. The method of claim 1 , further comprising work-up of the product wherein the work-up of the reaction product comprises:
neutralizing the reaction product, and
fractionating the reaction product.
16. The method of claim 15 , further comprising cooling the reaction product prior to neutralizing.