TON denotes how many maximum molecules of substrate can be converted into product per catalytic site of a given catalyst under defined conditions.
TOF is a measures of specific activity of a catalytic center of a given catalyst by the number of molecular reactions or catalytic cycles occurring at the centre per unit time. In other word, it is a number of revolutions of the catalytic cycle per unit time
TOF = (Number of molecules reacted)/ (Number of sites) x (time)
In order to measure active sites of the acid or base catalyst, chemisorption studies by TPD analysis can be used. You may refer following interesting papers:
Turnover Frequencies in Metal Catalysis:
Meanings, Functionalities and Relationships, DOI:10.1039/9781847553294-00320
Turnover Rates in Heterogeneous Catalysis, 10.1038/ncomms9618_calculate_the_TOFTurnover_frequency_and_the_amount_of_the_catalyst_active_sites_Thank_you