1,2-DIALKYL-3,5-DISUBSTITUTED PYRAZOLIUM SALTS

This invention relates to novel 1,2-dialkyl-3,5-di-substituted pyrazolium salts of the structure: wherein R1 and R2 each represent C1-C4 alkyl; R? is cyclo-alkyl-methyl of 3 - 7 carbon atoms, a cycloalkyl of 3 - 7 carbon atoms, methylcycloalkyl of 3 - 7 carbon atoms, cycloalkenyl of 3 - 7 carbon atoms, methycycloalkenyl of 3 - 7 carbon atoms, or alkyl (from 2 to 11 carbon atoms); R4 is cycloalkylmethyl of 3 - 7 carbon atoms, cycloalkyl of 3 - 7 carbon atoms, methyl cycloalkyl of 3 - 7 carbon atoms, C2-C11 alkyl or , where Z, Z', Y and Y' each represent hydrogen, halogen, nitro, methylthio, methylsulfonyl, cyano, carboxyl, carbalkoxy of 1 - 4 carbon atoms, alkyl of 1 - 8 carbon, haloalkyl of 1 - 4 carbon atoms and containing 1 - 4 halogen atoms, or alkoxy of from 1 - 4 carbon atoms; X is an anion with a charge of from 1 to 3; n is O or l; and m is an integer from 1 to 3, and to a method for the control of undesirable plant species therewith. There is also provided a method for the selective control of certain broadleaf weeds and undesirable grass plants with the above mentioned compounds.