| abstract |
The reaction of compounds of the formula: X2O3P CHY CZ2 where Y and each Z are each H, PO3X2, SO3X or CO2X (e.g. vinyl phosphonic acid or vinylidene diphosphonic acid) with hypophosphorous acid in the presence of free radicals provides novel compounds X2O3PCHYCZ2PO2XH which react with monomers such as vinyl sulphonate, vinyl phosphonate, vinylidene diphosphonate and acrylic acid to form telomers useful for scale inhibition, especially barium scale in oil wells. The polymers show better absorption to rock than PVSA and better thermal stability than random copolymers containing equivalent phosphorus. |