A simple program to solve the Eyring Equation and first/second order kinetics.

Download

You can download a release for Windows 10/11 which includes the executable Eyring Eq X.X.exe.

Alternatively, if you choose to set up your own environment:

Get a Python environment (tested on Python 3.9). Launch a shell/cmd/PowerShell window from the cloned directory. Run:

pip install pipenv
mkdir .venv
pipenv sync
pipenv run python Eyring_Eq.py

In literature, people often quote inexact rules like "21 kcal/mol at room temperature" when discussing calculated activation Gibbs free energies. They (sometimes including reviewers) might even ask for references to support these crude rules or ask for values at different conditions, which are difficult to find for the exact condition you need. In contrast, based on Eyring equation and first/second order kinetics (assuming the reaction is kinetically controlled), it's easy to calculate the reaction time, required temperatures, etc, exactly to our need. I created this simple program to automate these calculations.

To use the program, fill in the known values for the equations, and leave the unknown values blank. If the number of filled parameters is sufficient (and not excessive), the [Calculate] button will become available. Click it to get the values you left blank.

For example, you can calculate:

For a 21 kcal/mol unimolecular reaction to get a 98% conversion at 20 °C, you need 49 min.

For a second order reaction that can "finish" in 2 hours at 25 °C with a starting concentration of 0.01 mol/L, the Gibbs free energy corresponds to 81.8 kJ/mol

For a reaction with 120 kJ/mol activation Gibbs free energy (note that you do need to consider changes of Gibbs free energy relative to temperature) to get a 98% conversion within one day, the temperature needs to be 90 °C.

Or any other valid combination of known/unknown values.

The Batch/Batch_Template.xltx file is provided for calculating multiple set of input data.

Fill in the relevant data using the Excel template. Then submit the file(s) by clicking the "Batch" pushbutton in the GUI.

The program will run through every column, gather the unknowns, and generates a new file with suffix .Erying_Eq_Output.xlsx.

See examples in the Batch folder.

I believe the Eyring equation and the first/second order kinetics are old enough and well-known enough to not require citation. However, if you really need to cite this program, you can use the Zenodo DOI: .

E.g. Li, Y.-H. Eyring Equation and Chemical Kinetics Calculator X.X.X (DOI: 10.5281/zenodo.XXXXXXX), 2023. (Please change the info to respect the version you are using.)

• Eyring Equation:

$$k =\sigma\frac{k_B T}{h}\left ( \frac{R T}{1\ atm} \right )^{\Delta n}exp(-\frac{{\Delta G}^{\neq}}{R T})$$

• First order kinetics:

$$c = c_{0}\ exp(-kT)$$

• Second order kinetics:

Starting with different concentration for species A and B (could someone tell my why the zeros are not subscripted?):

$$ln\frac{[B] [A]{0}}{[A] [B]{0}} = k([B]{0}-[A]{0})t$$

Starting A and B at the same concentration:

$$\frac{1}{[A]} = \frac{1}{[A]_{0}}+kt$$

1.3

• Support batch automation.
• Remembering the parameters used last time; added a re-calculate button.
• Bug fix for negative Celsius temperatures.

1.2

• Support A+Cat->P+Cat mode.
• Support kcal/mol, eV, min, h, day, year units.
• Add shortcut to pushbuttons.
• Add sanity check for inputs.
• Solve number overflow, divided by zero problem when conversion is too close to 100%.
• Add automatic tests.
• Correct number representation function using floor instead of round.
• Switch to PyQt6 for better high DPI support.
• Switch to pipenv for smaller packed exe.