Phenolformaldehyde resins were obtained by polycondensation of concentrated phenols with formaldehyde in the presence of hydrochloric acid. Concentration of phenols is carried out by treating the phenolic fraction of coal tar with an aqueous solution of sodium hydroxide followed by neutralization of water-soluble phenolates with hydrochloric acid. The kinetic dependences of resin yield and softening temperature on the duration of the process at 333, 353, and 373 K were obtained. The order of the reaction was determined and the effective activation energy of this process was determined by a graphical method. In the interval 333-373 K for polycondensation reactions, the equation of the dependence of the resin yield on the temperature and duration of the process was obtained.