Substd. propane-(1,3)-diphosphonic and-diphosphinic acids - useful as corrosion- and scaling inhibitors

摘要

Propane-1,3-diphosphon-(or -in)ic acids are of formula (I) and their salts are new: In the formula, R1 and R2 are each H when a or b = 1, or, when a or b = 0, opt. substd. 1-8C alkyl or opt. substd. Ph; R3 is H, opt. substd. 1-4C alkyl, opt. substd. Ph; F, Cl, Br, OH, 1-8C alkoxy, carboxyl or -P(O)-(O)a-R1OH; R4 is H, 1-4C alkyl, 2-3C alkenyl, opt. substd. Ph, carboxyl, F, Cl or -P(O)-(O)a-R1OH; R3 and R4 may also form a divalent radical -(CH2)n-, where n = 3-5. R5 is H, 1-4C opt. substd. alkyl, (Me)-carboxymethyl or carboxyethyl, a succinyl gp. or -CHR4-CHR3-P(O)-(O)a-R1-OH or -CH2-P(O)-(O)a-R1OH; R6 is opt. substd. Ph or when R5 = carboxymethyl, is carboxy. a and b are each 0 or 1, or a salt of cpd. (I). Cpds. (I) are useful as corrosion inhibitors and antiscale agents, which are added to liquors to protect metallic surfaces that they contact.