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Turnover Frequency Calculator

Our chemical kinetics calculator computes turnover frequency accurately. Enter measurements for results with formulas and error analysis.

Reviewed by Manoj Kumar, Mathematics Educator

Reviewed by Manoj Kumar, Mathematics Educator

Formula

TOF = (moles product) / (moles catalyst * time)

Turnover frequency measures catalytic activity as the number of catalytic cycles per unit time. TON = moles product / moles catalyst gives total turnovers. TOF = TON / time gives the rate. Higher values indicate more efficient catalysts.

Worked Examples

Example 1: Homogeneous Catalyst TOF

Problem:A palladium catalyst (0.001 mol) produces 0.50 mol of product in 2 hours. Calculate TON and TOF.

Solution:TON = 0.50 / 0.001 = 500\nTOF = 500 / 2 h = 250 h^-1\nTOF = 250 / 3600 = 0.0694 s^-1

Result:TON = 500, TOF = 250 h^-1 (0.0694 s^-1)

Example 2: Industrial Hydrogenation Catalyst

Problem:A hydrogenation catalyst (0.0005 mol active sites) converts 10 mol of alkene in 30 minutes.

Solution:TON = 10 / 0.0005 = 20,000\nTOF = 20,000 / 0.5 h = 40,000 h^-1\nTOF = 40,000 / 3600 = 11.11 s^-1

Result:TON = 20,000, TOF = 40,000 h^-1 (11.11 s^-1)

Frequently Asked Questions

What is turnover frequency (TOF) in catalysis?

Turnover frequency is a measure of catalytic activity defined as the number of moles of substrate converted per mole of catalyst per unit time. It quantifies how many times a catalyst completes its catalytic cycle in a given time period. Higher TOF values indicate more active catalysts. TOF is typically reported in units of inverse time (s^-1, min^-1, or h^-1). Industrial catalysts often have TOF values ranging from 0.01 to over 100,000 per second, depending on the reaction type.

What factors affect turnover frequency?

Several factors influence TOF including temperature, pressure, substrate concentration, catalyst structure, and reaction medium. Higher temperatures generally increase TOF following the Arrhenius relationship. Catalyst poisoning, sintering, or leaching can decrease TOF over time. The support material in heterogeneous catalysis affects active site accessibility. Solvent effects can alter reaction barriers. Catalyst loading also matters as too much catalyst can lead to site blocking while too little may not provide sufficient activity for practical applications.

References

Reviewed by Manoj Kumar, Mathematics Educator · Editorial policy