Sulfonation process

Claim 1

A PROCESS FOR PREPARING SYNTHETIC ALKYL ARYL SULFONIC ACIDS HAVING A MOLECULAR WEIGHT IN THE RANGE OF 400 TO 900, WHICH COMPRISES MIXING A HYDROCARBON FEED STOCK FREE FROM HYDROCARBONS HAVING MORE THAN ONE AROMATIC NUCLEUS, SAID FEED STOCK HAVING A SULFONATABLE HYDROCARBON CONTENT ABOVE 60 VOLUME PERCENT AND HAVING AS RECEIVE INGREDIENTS SYNTHETIC ALKYL BENZENE HYDROCARBONS HAVING 1 TO 3 ALKYL SUBSTITUENTS OF SUCH SIZE THAT THE ALKYL PORTION OF THE MOLECULE CORRESPONDS TO A MOLECULAR WEIGHT IN EXCESS OF 240 BUT THE ENTIRE MOLECULE HAS A MOLECULAR WEIGHT NO GREATER THAN 390, WITH AN INERT, SULFURIC ACID-TREATED PETROLEUM DISTILLATE OIL HAVING A SULFONATABLE HYDROCARBON CONTENT OF LESS THAN 0.5%, A BOILING RANGE WITHIN THE LIMITS OF 200* TO 800*F., AND HAVING A VISCOSITY IN THE RANGE OF 50 TO 350 SSU AT 100* F., IN AMOUNTS SUFFICIENT TO OBTAIN A RESULTING MIXTURE HAVING A SULFONATABLE HYDROCARBON CONTENT ABOVE 30 VOLUME PERCENT AND A VISCOSITY OF LESS THAN 450 SSU AT 100*F., REACTING SAID RESULTING MIXTURE WITH A SULFONATING AGENT IN AMOUNTS SUFFICIENT TO PROVIDE 2 TO 7 MOLS OF SO3 PER MOL OF SULFONATABLE HYDROCARBON IN SIAD RESULTING MIXTURE, THE REACTION BEING CARRIED OUT AT TEMPERATURES IN THE RANGE OF 32* TO 175*F. FOR A TIME IN THE RANGE OF 2 TO 90 MINUTES, SEPARATING SLUDGE FROM THE REACTION PRODUCTS, AND RECOVERING A SULFONIC ACID-CONTAINING ACID OIL.