Abstract: Alkanolamine salts of amide acids having the formula: ##STR1## in which the circle represents a single nucleous aromatic ring or a monocyclic or bicyclic aliphatic ring system in each case with 5 or 6 carbon atoms per ring in which R.sup.1 represents an isoalkyl radical with the longest chain of 6 to 8 carbon atoms and a total of 8 to 12 carbon atoms; R.sup.2 represents a radical alkylene-X wherein the alkylene chain is a branched or straight chain and contains 1 to 4 carbon atoms; X represents OR.sup.3, O(C.sub.2 H.sub.4 O).sub.n -R.sup.3, O(C.sub.3 H.sub.6 O).sub.n -R.sup.3, NR.sup.3 R.sup.3, CN, CONH.sub.2, and COOR.sup.3 ; R.sup.3 represents hydrogen or C.sub.1 to C.sub.4 alkyl; n is an integer of 1 to 4; and wherein the carboxyl and carbonamide groups in said formula are bonded to non-olefinic carbon atoms and arranged in adjacent positions. The use of these salts as corrosion inhibitors in aqueous systems is also disclosed.

Abstract: Products which have been obtained by reacting an acid of the formula I ##STR1## where R.sup.1 and R.sup.2 are hydrogen, fluorine, chlorine, bromine or alkyl or alkoxy of 1 to 4 carbon atoms, but the sum of the carbon atoms of R.sup.1 and R.sup.2 is not greater than 7 and preferably not greater than 3, A is a benzene, naphthalene or anthracene radical or a biphenyl structure, such as a diphenyl, diphenylmethane, diphenyl ether, diphenyl sulfide, diphenyl sulfoxide or diphenyl sulfone radical, R.sup.3 is hydrogen, alkyl of not more than 4 carbon atoms, .beta.-cyanoethyl or hydroxyalkyl of 2 to 4 carbon atoms, R.sup.4 is hydrogen, fluorine, chlorine, bromine, alkyl or alkoxy of 1 to 4 carbon atoms, hydroxyl or carboxyl and X is --SO.sub.2 -- or --CO--, with an amine of the formula II ##STR2## where R.sup.5 and R.sup.6 are hydrogen, C.sub.1 -C.sub.4 -alkyl, C.sub.2 -C.sub.4 -hydroxyalkyl and/or ##STR3## R.sup.7 and R.sup.8 being hydrogen, C.sub.1 -C.sub.4 -alkyl or C.sub.2 -C.sub.

Abstract: A process for preventing the corrosion of metals in aqueous systems by means of low-foam corrosion inhibitors consisting of alkanolamine salts of maleamic acids.