Fluorinated aromatic compounds are important chiral building blocks in the pharmaceutical industry. One of the methods for their synthesis is a biocatalytic path with enzyme halohydrin dehalogenase (HHDH). In this work, the ring-opening reaction of epoxides was studied. Substrates were fluorinated derivates of styrene oxide with azide as a nucleophile. The reaction was catalyzed by wild-type HHDH, also known as HheC. Preliminary reactions were ran in a buffered medium with 5 % of organic solvent. Six different epoxides with fluorine atom on different positions of the phenyl ring were evaluated. By using the initial reaction rate method, kinetic models and parameters for each reaction were determinend. The influence of the concentration of epoxides (cepox) on the rate of enzymatic reactions fits Michaelis-Menten kinetics, while the influence of azide concentration fits the Michaelis-Menten kinetics with substrate inhibition. Because of low epoxide solubility, enzymatic kinetic in the water medium can be determined up to the epoxide concentration of 20 mM. To increase epoxide solubility reactions need to be carried out at higher concentration of organic solvent. By comparing the estimated kinetic parameters and literature search, it was found that the substituent position has a deterministic role in enzyme activity and affinity of the substrate towards the enzyme. From the tested styrene oxides, the best substrate for HheC is the one that has substituents on the opposite side from the epoxide ring.