The reaction of olefins with carbon monoxide and hydrogen to form carboxylic acids can be conducted using proton catalysts. Mineral acids such as H₂SO₄, HF, and H₃PO₄, alone or in combination with BF₃ or SbF₅, e.g., in HF^.SbF₅, are particularly suitable.

In the initial step of the reaction, a proton adds to the olefin to form a secondary carbenium cation, which is stabilized by isomerization of the double bond and rearrangement of the carbon skeleton:

CO then adds to the tertiary carbenium ion to form an acylium cation, which goes on to react with either (to form a carboxylic acid) or with an alcohol (to form an ester directly):

Thus, mixtures of isomeric branched carboxylic acids are obtained in which the fraction of tertiary carboxylic acids depends on the reaction conditions. For example, at 80 °C, 20-100 bar and longer reaction periods, all butene isomers can be converted into pivalic acid (trimethylacetic acid). In practice, isobutene is normally used for the manufacture of this acid:

The carbenium ion intermediate can also be obtained from precursors other than the olefin. Isobutanol and 2-chlorobutane can also be used for pivalic acid manufacture, since they are subject to loss of H₂O or HCl, respectively, under the conditions of the reaction.

In the industrial process, CO is added to the olefin in the presence Of Catalyst in a multistage stirred-tank reactor at 20-80 °C and 20-100 bar. Water is introduced in the second step. H₃PO₄/BF₃ is the preferred proton-supplying catalyst, because a separation of product and catalyst phase occurs when H₂O is added. H₃PO₄/BF₃ is recycled to the process. In a more recent process development from BASF, a heterogeneous zeolite catalyst (pentad type) is used at 250-300 °C and 300 bar.

With high olefin conversion, the selectivity to tertiary carboxylic acids is 80- 100%. The byproducts are carboxylic acids from the dimerized olefins.

Shell, Exxon, Kuhlmann and Du Pont operate industrial processes based on the Koch reaction. Besides the manufacture of pivalic acid from isobutene, branched C₆ -C₁₁ carboxylic acids are produced from the corresponding olefins. The acids are commercially known as 'Versatic Acids' (Shell), 'Neo Acids' (Exxon), or 'CeKanoic Acids' (Kuhlmann).