Dimerization process

Claim 1

A PROCESS FOR SELECTIVE PREPARATION FROM AN ALIPHATIC CONJUGATED DIOLEFIN OF DIALKALI METAL SALTS OF ALIPHATIC UNSATURATED DIACIDS HAVING TWO MORE CARBON ATOMS PER MOLECULE THAN A DIMER OF THE DIOLEFIN WHICH COMPRISES AN INITIAL STEP OF REACTING AN ALIPHATIC CONJUGATED DIOLEFIN WITH A FINELY DIVIDED ALKALI METAL IN AN ETHER REACTION MEDIUM OF THE GROUP CONSISTING OF ALIPHATIC MONOETHERS HAVING A METHOXY GROUP AND AN OXYGEN TO CARBON RATIO OF NOT LESS THAN 1:4 AND POLYETHERS DERIVED FROM AN ALIPHATIC POLYHYDRIC ALCOHOL HAVING ALL THE HYDROXYL HYDROGEN ATOMS REPLACED BY ALKYL GROUPS AND MIXTURES THEREOF IN THE PRESENCE OF A SMALL AMOUNT, BASED ON THE WEIGHT OF THE DIOLEFIN, OF A POLYCYCLIC AROMATIC HYDROCARBON AT A TEMPERATURE BELOW ABOUT O* C. THEREBY PROVIDING A REACTION MIXTURE COMPRISING SELECTIVELY FORMED DIALKALI METAL DERIVATIVES OF THE UNSATURATED HYDROCARBON DIMERS OF SAID DIOLEFIN, AND IN A SUBSEQUENT STEP CARBONATING DIALKALI METAL DERIVATIVES PRODUCED IN SAID INITIAL STEP AND UNSEPARATED FROM SAID REACTION MIXTURE TO CONVERT SAID DERIVATIVES TO THE CORRESPONDING DIALKALI METAL SALTS OF ALIPHATIC UNSATURATED DICARBOXYLIC ACIDS HAVING TWO MORE CARBON ATOMS PER MOLECULE THAN A DIMER OF SAID DIOLEFIN.