Manufacture of metal salts of dialkyl dithiophosphoric acids and concentrate in oil solution

Claim 1

A PROCESS WHICH COMPRISES: FORMING A DIALKYL DITHIOPHOSPHORIC ACID BY REACTING A MIXTURE OF TWO MONOHYDRIC ALCOHOLS HAVING IN THE RANGE OF 3 TO 6 CARBON ATOMS PER MOLECULE WITHIN THE RANGE OF 0.225 TO 0.275 MOLE OF PHOSPHORUS PENTSULFIDE, PER MOLE OF ALCOHOL, AT A TEMPERATURE IN THE RANGE OF 160 TO 200*F. AND FOR A TIME IN THE RANGE OF 1 TO 6 HOURS WHILE MAINTAING THE SPECIFIC GRAVITY OF THE REACTION MIXTURE IN THE RANGE OF 1.015 TO 1.035 AND THE COLOR OF THE REACTION MIXTURE DARK, COOLING THE DIALKYL DITHIOPHOSPHORIC ACID SO OBTAINED TO A TEMPERATURE BELOW 110*F., SEPARATING SOLIDS FROM THE ACID SO COOLED, NEUTRALIZING THE ACID WITHIN THE RANGE OF 0.52 TO 0.60 MOLE, PER MOLE OF ACID, WITHIN THE RANGE OF AGENT SELECTED FROM THE GROUP CONSISTING OF OXIDES AND HYDROXIDES OF ZINC, THE NEUTRALIZATION BEING CARRIED OUT AT A TEMPERATURE IN THE RANGE OF 140 TO 200*F., THEREAFTER HOLDING THE NEUTRALIZED REACTION MIXTURE HAVING A WATER CONTENT OF 0.5 TO 4 WEIGHT PERCENT AT A TEMPERATURE IN THE RANGE OF 150 TO 200*F. AND A PH IN THE RANGE OF 6.0 TO 6.6 FOR A TIME IN THE RANGE OF 1 TO 4 HOURS, DILUTING THE NEUTRALIZED PRODUCT THUS OBTAINED WITHIN THE RANGE OF 5 TO 20 WEIGHT PERCENT OF A DISTILLATE OIL HAVING A VISCOSITY IN THE RANGE OF 35 TO 45 SSU AT 210*F., SEPARATING SUBSTANTIALLY COMPLETELY ALL INORGANIC SALTS FROM THE DILUTED NEUTRALIZED PRODUCT WHILE MAINTAINING THE WATER CONTENT THEREOF IN THE RANGE OF 0.5 TO 4 WEIGHT PERCENT, AND DRYING THE FILTERED MATERIAL TO A WATER CONTENT OF LESS THAN 0.5 WEIGHT PERCENT TO OBTAIN A CLEAR, ODORLESS, HYDROGEN SULFIDE FREE OIL SOLUTION OF A DIALKYL DITHIOPHOSPHORIC ACID SALT.