Volume 23, Number 3
1999

Activation Energy & the Arrhenius Equation

The following query and reply were posted on the Conservation Research discussion list (conservation-research-request@mailbase.ac.uk) in May 1999 and are reprinted here with permission of both parties, to make activation energy and the Arrhenius equation more meaningful for preservation professionals in libraries and archives.

William (Bill) Fleming wrote:

To carry out rapid artificial aging of paper or linen the Arrhenius equation is often used. However, to do this, the activation energy value of the particular material is needed. It's difficult to find published data on this and everyone seems to use a number seemingly plucked from thin air. Where can these values be found, or can they be found experimentally? Any and all advice would be most welcome.

Matthew Collins responded, saying:

The Arrhenius equation can be dangerous if used inappropriately.

The equation can be used to establish the temperature dependence of a specific reaction. In our work on protein deterioration we use heating experiments to establish first the rate law of a particular reaction and from this the reaction rate. Experiments at different temperatures are then used to establish the relationship between the rate of this reaction and temperature.

Since aging may potentially involve many different reactions with different activation energies, it is important to establish the reaction, or reactions, which alter the property you are interested in. Those reactions with the lowest activation energies will have a disproportional influence on the fate of the material at low temperature compared with high temperature heating experiments.