Kolbe's electrolysis reaction for alkenes' production

I came across a question in which the major product was asked for Kolbe's electrolysis of potassium salt of 2,3-dimethylbutane-1,4-dioic acid. The answer was given as trans-(but-2-ene). I couldn't understand how does the trans isomer form as the specific major product from this reaction, following free radical mechanism. Would someone please help me with this. Thanks!




It has little to do with mechanism and more to do with the fact that stable products are, in general, the major products in most of the chemical reactions.


In this case, trans-(but-2-ene) is more stable than cis-(but-2-ene), due to steric reasons.


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Generally during electrolysis of dicarboxylic acid we will get a few different products but the main product is unsaturated hydrocarbon. Maybe at this point, based on ChemElectroChem, 2020, 7, 4874 - down of page, the mechanism reaction is like in drawing:


[![enter image description here](https://i.stack.imgur.com/bWi0f.png)](https://i.stack.imgur.com/bWi0f.png)


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