ɪn məlˈɛkjʊlɚ dɪstɪlˈeɪʃən, flˈuːɪdz ɑːɹ ɪnðə fɹˈiː məlˈɛkjʊlɚ flˈoʊ ɹeɪʒˈiːm, ˈaɪ.ˈiː. ðə mˈiːn fɹˈiː pˈæθ ʌv mˈɑːlɪkjˌuːlz ɪz kˈɑːmpɚɹəbəl tə ðə sˈaɪz ʌvðɪ ɪkwˈɪpmənt.
In molecular distillation, fluids are in the free molecular flow regime, i.e. the mean free path of molecules is comparable to the size of the equipment.