Preparation of water-soluble sulfonation products from polymers of arvinyltoluene and acrylonitrile

Claim 1

IN A METHOD FOR THE PREPARATION OF WATER-SOLUBLE RESIN SULFONATES THE STEPS OF FORMING A SUBSTANTIALLY HOMOGENEOUS DISPERSION IN LIQUID SULFUR DIOXIDE OF A COPOLYMER OF FROM ABOUT 90 TO ABOUT 98 PERCENT BY WEIGHT OF AR-VINYLTOLUENE AND CORRESPONDINGLY FROM ABOUT 10 TO ABOUT 2 PERCENT BY WEIGHT OF ACRYLONITRILE, MIXING THE DISPERSION WITH A TOTAL OF AT LEAST 0.7 MOLECULAR EQUIVALENT OF A SULFONATION AGENT PER MOLECULAR EQUIVALENT OF MONOMERIC COMPOUNDS CHEMICALLY COMBINED IN THE COPOLYMER, THE SULFONATION AGENT CONSISTING OF FROM ABOUT 10 TO ABOUT 90 MOLE PERCENT CHLOROSULFONIC ACID AND CORRESPONDINGLY FROM ABOUT 90 TO ABOUT 10 MOLE PERCENT SULFUR TRIOXIDE, IN THE PRESENCE OF LIQUID SULFUR DIOXIDE AS A REACTION MEDIUM, THE PROPORTION OF SULFUR DIOXIDE BEING SUCH THAT THE RESIN SULFONATE PRODUCT IS NOT MORE THAN 5 PERCENT BY WEIGHT OF THE WHOLE MIXTURE, AND MAINTAINING THE MIXTURE AT A REACTION TEMPERATURE NOT HIGHER THAN 40* C., THE STARTING COPOLYMER OF AR-VINYLTOLUENCE AND ACRYLONITRILE BEING ONE WHOSE SOLUTION IN NINE TIMES ITS WEIGHT OF TOLUENE HAS A VISCOSITY IN CENTIPOISES AT 25*C. NOT GREATER THAN THAT REPRESENTED BY A POINT ON THE LINE DEF IN THE ACCOMPANYING DRAWING CORRESPONDING TO THE MOLE PERCENT CHLOROSULFONIC ACID IN THE SULFONATION AGENT.