Abstract: A general-purpose organic rust initiator which can effectively prevent corrosion of metals comprising a compound of formula (1): ##STR1## wherein R.sub.1 is a perfluoroalkyl group having 1 to 6 carbon atoms; R.sub.2 is a hydrogen atom or a group defined for R.sub.1 ; R.sub.4 is an acid group selected from --OH, --COOH, --SH, --SO.sub.2 OH, --PO(OH).sub.2, --SCH.sub.2 COOH, --SO.sub.2 NHCH.sub.2 COOH or a salt thereof; R.sub.3 is a hydrogen atom or a group defined for R.sub.4 ; or R.sub.3 and R.sub.4 together form an acid group selected from --N.dbd.N--NH--, --CH.dbd.N--N--, --SO.sub.2 --NH--CO--, --S--C(SH).dbd.N-- or a salt thereof.

Abstract: The invention concerns low molecular weight copolymers of acrylic acid or at least partially salified acrylic acid and acrylamide, their process of manufacture and their use. These copolymers may be used to prevent the formation of deposits on the walls of oil or geothermal equipment from aqueous systems containing dissolved salts. The copolymer is characterized in that it comprises recurrent units deriving from acrylic acid and acrylamide in a proportion by weight from 95:5 to 25:75. Furthermore, the distribution of the molecular weights of the copolymer, as determined by exclusion analytic chromatography, is such that at least 60% of the weight molecular weights are lower than 500.