Patent name: METHOD FOR PURIFICATION OF PHENOL
Patent Number: US 5,502,259
March 26, 1996
The invention relates to a method for purification of phenol and specifically to a method for purification of phenol produced within the process of joint phenol and acetone production by cumene method. The aim of the invention is to develop a catalyst which has high activity for phenol purification from organic mico-impurities with regeneration of the catalyst and which has high mechanical strength and stability with long catalyst life. This result is obtained by phenol purification using a heterogeneous zeolite catalyst. The acidity of the catalyst measured by butane cracking (KA) is more than 10. It is preferable to use zeolites which are designated according to the classification of the International Zeolite Association by indices FAU (zeolites X, Y), MFI (for example, ZSM-5), MOR (mordenite), MAZ (omega), BEA (beta), FER (ferrierite) and others. These zeolites can be used with binders (aluminum oxide, silica gel, aluminosilicates or aluminophosphates) and without them. It is preferable to use zeolite of the Y type with an aluminosilicate binder and a value of KA =50-80 cm3 /min*g and Si/Al ratio more than 3. The concentration of sodium, potassium and other alkali agents on the basis of their oxides does not exceed 2 wt %, preferably not more than 0.3 wt %. It is preferable to use zeolites with medium and large pores. Size of zeolites pores should be within the range 4 A in diameter and more. The most preferable zeolites are with large pores (>6 A in diameter) such as Y and mordenite.