The equation for producing ethyl propanoate from iodoethane is as follows:

```

CH3CH2I + CH3CH2COO-Na+ → CH3CH2COOCH2CH3 + NaI

```

In this reaction, iodoethane (CH3CH2I) reacts with sodium propanoate (CH3CH2COO-Na+) to produce ethyl propanoate (CH3CH2COOCH2CH3) and sodium iodide (NaI). The reaction is typically carried out in a polar solvent, such as ethanol or water, at room temperature.