Kolbe electrolysis
In the well-known kolbe electrolysis, a carboxy salt in aqueous solution is split, the positive ions migrating to the cathode, the negative ions to the anode, where CO2 is released and two remaining bits join to form an alkane. ..So, for example, say the salt is sodium butanoate – at the cathode an HOH is split and NaOH created, with H2 being released. ..At the anode, CO2 is released and hexane is created. At least, those are the principle products, though minor amounts of other products will be formed.
Hexane is a very useful fuel as is for use in diesel engines, plus it is readily rearranged over a catalyst to give several branched entities, all still with six carbon atoms, which is an excellent gasoline with an octane number of about 85.
Variant Electrolysis
In a variant of the Kolbe electrolysis, the electolyte is primarily a ketone with ~6% by volume of HOH. ..Either acetone or butanone may be employed. ..The reaction at the cathode remains the same, but at the anode there is a difference. CO2 is again released, but an alkane is not formed. ..Instead, an HOH is split with the OH- being used to create an alcohol, while the H+ draws an H+ from another acid remainder to release H2 and leave an alkene.
So for sodium butanoate is created at the cathode mainly CO2, propanol, propene, and H2, though there will likely be some other products also. ..
In a 2nd step, the propanol may be added to the double bond of the propene, thereby created a branched entity with six C and one O molecules which will serve as a gasoline having a good octane number. ..It is an ether and would be named as such (I presume). However, another name that is descriptive is 2.propanopropane.
note: _This was disclosed in 1959 in US Patent 2.867.569, though how well it works – who knows? The electrolysis apparatus they used mixed the CO2 and NaOH creating very pure Na bicarbonate which dropt out, being insoluble in the ketone electrolyte. …Obviously, this is ‘green’ sodium bicarbonate. In North America almost all Na bicarbonate is made from material dug up from deposits of a mineral in Wyoming, which makes it very ‘ungreen’ …in case anyone cares.