Process for the manufacture of 2,2,4,4-tetramethylcyclobutanediol

Process for the manufacture of 2,2,4,4-tetramethylcyclobutane- 1,3-diol which comprises the steps of:

• (1) feeding isobutyric anhydride to a pyrolysis zone wherein the isobutyric anhydride is heated at a temperature of about 350 to 600.degree. C. to produce a vapor effluent comprising dimethylketene, isobutyric acid and unreacted isobutyric anhydride;
• (2) rapidly cooling the vapor effluent to condense isobutyric acid and isobutyric anhydride and separating the condensate from the dimethylketene vapor;
• (3) feeding the dimethylketene vapor to an absorption zone wherein the dimethylketene vapor is contacted with and dissolved in a solvent comprising 2,2,4,4-tetramethylcyclobutane-1,3-dione to produce an effluent comprising a solution of dimethylketene in the solvent;
• (4) feeding the absorption zone effluent to a dimerization zone wherein the dimethylketene is converted to 2,2,4,4 tetramethylcyclobutane-1,3-dione to produce an effluent consisting essentially of 2,2,4,4 tetramethylcyclobutane 1,3 dione;
• and
• (5) feeding the dimerization zone effluent to a hydrogenation zone wherein the effluent is contacted with a supported hydrogenation catalyst under hydrogenation conditions of pressure and temperature to produce an effluent comprising a solution of 2,2,4,4-tetramethylcyclobutane 1,3-diol in the solvent.