Abstract: A process of preparing an alkylated phenol which is substantially monoalkylated and para oriented which comprises reacting phenol with a C.sub.4 -C.sub.9 olefin and wherein said olefin is utilized in about 5-10% stoichiometric excess. The broad reaction temperature utilized is about 60.degree.-105.degree. C and the time of reaction is at least 30 minutes. The catalyst utilized is anhydrous H.sub.3 PO.sub.4 which is used in a value of at least 8% based upon the weight of reactant phenol. The preferred products are p-t-amylphenol and p-t-butylphenol, and in the process of preparing these preferred phenols, the olefin may be reacted in 5-8% stoichiometric excess and the reaction temperature utilized may be 95.degree.-115.degree. C. An additional preferred product is p-nonylphenol derived from a branched propylene trimer.