You can easily calculate the equivalent COD as following:

1- Balance the equation: CH3COOH + O2 = H2O + CO2 (you can use this link: https://www.webqc.org/balance.php)

2- Divide the resulted MW of oxygen by the corresponding MW of compound (CH3COOH) > this will be the ratio.

For example, for the acetic acid, it is 1.07

Good luck

Thank you sir for the detailed explanation @Dr. Elreedy

Just some tips: when you balance simple oxydation equations like the ones you need, you start with C balance, then you proceed with H and finally you balance O, obtaining the moles of oxygen you need. The balanced equations are:

CH3COOH+2O2=2CO2+2H2O

CH3CH2COOH+3.5O2=3CO2+3H2O

CH3(CH2)10COOH+17O2=12CO2+12H2O

At that point, you need to consider the moles of oxygen you need for oxidizing a mole of compound (respectively 2, 3.5 and 17), and multiply the moles for the atomic weigth, to obtain COD value (expressed as g O2/g compound):

COD1= g O2/g CH3COOH=2*32/60=1.07

COD2=g O2/g CH3CH2COOH=3.5*32/74=1.51

COD3=g O2/g CH3(CH2)10COOH=17*32/200=2.72

Regards

Many many thanks for the suggestion and explanation, sir @Dr. Mainardis

@Parvin

The acetate oxidation equation should be used