Patent ID: 8505626

Claim:
A method of inhibiting scale formation in water using an aminoacid alkyphosphonic acid compound having the general formula: A-(B) x wherein A is an α-amino acid moiety selected from the group of: arginine; histidine; isoleucine; leucine; methionine; threonine; and phenylalanine; and wherein B is an alkyiphosphonic acid moiety having from 1 to 6 carbon atoms in the alkyl group; with the proviso that x is an integer of from 1 to 6 in the event the amino acid moiety is arginine and from 1 to 3 in the event the amino acid moiety is histidine and x is 2 in the event the amino acid moiety is selected from leucine, isoleucine, methionine, threonine and phenylalanine in scale forming water systems containing more than 100 mg barium and/or strontium and/or calcium carbonate hardness per liter, said systems having a pH between 2 and 10, whereby from 0.1 to 800 ppm of the aminoacid alkyiphosphonic acid scale inhibitor are added to the scale forming water system.