Alkylation is the process of introducing an alkyl substituent into the molecule of an organic compound. Typical alkylating agents are alkyl halides, alkenes, epoxy compounds, alcohols, and less commonly aldehydes, ketones, ethers, sulfides and diazoalkanes. Alkylation catalysts include mineral acids, Lewis acids, and zeolites. Alkylation is widely used in the chemical and petrochemical industries. This reaction underlies the production of a number of important chemical reagents, including plasticizers, stabilizers, additives for polymeric materials, surfactants and pharmaceuticals. Despite the fact that the study of the phenol alkylation reaction dates back to the first half of the last century, the development of new effective catalytic systems and the search for more optimal conditions for carrying out these reactions still remain relevant. The article presents the results of a study of the alkylation reaction of phenol with ethylene oligomers in the presence of a KU-23 cation exchange catalyst in a batch plant. The chemical scheme of the reaction and the mechanism of its occurrence are shown. The influence of various reaction factors, such as temperature, duration of the experiment, molar ratio of the starting reagents and catalyst weight, on the yield and selectivity of the resulting products was studied. On the basis of the obtained results, it was established that under optimal conditions, the yield of the target product para-alkyl phenol is 74.2% of theory for the phenol taken, and the selectivity is 88.4%. The structure of para-alkylphenol was established by spectral and chemical methods
