Process for purifying triaryl phosphates by reduced pressure distillation and phenol injection

Abstract

Abstract REACTION MIXTURES, RESULTING FROM THE PHOSPHORYLATION OF A MIXTURE CONTAINING PHENOL; ORTHO-, META- AND PARAALKYLPHENOL; 2,6-, 2,4-, 2,5- AND 3,5-DIALKYLPHENOLS, 2,4,6AND 2,3,5-TRIALKYLPHENOLS WITH PHOSPHORUS OXYCHLORIDES, CONTAINING TRIS (ALKYLPHENYL) PHOSPHATE ESTERS, UNTREACTED ALKYLPHENOLS AND GENERALLY A CATALYST RESIDUE ARE PURIFIED TO REMOVE THE UNREACTED ALKYLPHENOLS BY (1) DISTILLING THE REACTION MIXTURE AT AN ELEVATED TEMPERATURE AND REDUCED PRESSURE TO REMOVE MOST OF THE UNREACTED ALKYLATED PHENOLS (GENERALLY HINDERED ALKYLATED PHENOLSA), (2) SPARGING PHENOL INTO THE REMAINING REACTION MIXUTRE FOR ONE-HALF TO SEVERAL HOURS AT ELEVATED TEMPERATURES AND REDUCED PRESSURE TO REMOVE REMAINING HINDERED PHENOLS NOT ONLY BY A SIMPLE ENTRAINING MECHANISM BUT ALSO, APPARENTLY, BY TRANSALKYLATION AND TRANSESTERIFICATION REACTIONS, LEAVING ESSENTIALLY ONLY UNHINDERED PHENOLS IN THE PRODUCT PHOSPHATE ESTER, (3) DISTILLING THE SPARGED REACTION MIXTURE TO SEPARATE THE PHOSPHATE ESTER AND UNHINDERED PHENOLS FROM THE REACTION RESIDUE WHICH ALSO GENERALLY CONTAINS A CATALYST RESIDUE, AND (4) FURTHER PURIFYING THE PRODUCT BY CONVENTIONAL MEANS SUCH AS CAUSTIC WASHING AND/OR ACTIVATED CARBON TREATMENT TO REDUCE THE COLOR OF THE TRIS(ALKYLPHENYL) PHOSPHATE ESTERS.

Inventors

• 👤 Edward F Orwoll

Bibliographic Details