Succinic acids substituted in one of their methylene groups by one saturated or unsaturated hydrocarbon residue containing at least five carbon atoms are reacted with nitrogen compounds containing at least one hydrogen atom combined to a nitrogen atom. Amides or imides are obtained. The acids may be replaced by their anhydrides or chlorides. Suitable acids are the products obtained according to Specification 441,016, or by the condensation of olefines such as n-decylene, n-dodecylene or n-octadecylene, or of polymerization products of olefinic nature with a -b -unsaturated dicarboxylic acid anhydrides or compounds which are converted into said anhydrides, in particular, isononenyl- and isopentadecenyl succinic acids, the anhydrides of which are obtained by condensation of isononylenes and isopentadecylenes with maleic acid anhydride. Suitable nitrogen-containing compounds are ammonia, aliphatic or aromatic amines, e.g. monomethylamine, dibutylamine, hydroxy-ethylamine, aniline, ethylaniline, diphenylamine, a -naphthylamine and benzylamine, amines of the alicyclic series, aminocarboxylic acids such as glycocoll and anthranilic acid, and aminosulphonic acids such as taurine. Condensation may be carried out in an inert solvent, e.g. benzene, benzine, ligroin, carbon tetrachloride, dioxane. Monamides are generally first formed, and when these contain a hydrogen atom linked to a nitrogen atom they are converted by heating to the imides. Diamides are generally obtained when considerable excess of the nitrogen-containing compound is used in the presence of an agent which splits off water, e.g. a hydrosilicate such as Tonsil. Products containing at least one acid group are particularly suitable as capillary active agents and soap-substitutes, as wetting, washing, cleansing, emulsifying, dispersing, foaming and penetrative agents. Advantageous wetting agents are, for example, those amidocarboxylic acids obtained by condensation of the succinic acids with monomethylamine, dibutylamine, aniline, ethylaniline, a -naphthylamine, benzylamine, cyclohexylamine, and diamides and imides obtained by condensation of the succinic acids with amines containing a further acid group, e.g. glycocoll, aminophenyl acetic acid, anthranilic acid and taurines. Alkali and ammonium salts are suitable. The capillary active agents may be employed alone, or in admixture with other substances, for example, oxygen-evolving substances, or other capillary active, neutral or alkaline substances. In examples: (1) ammonia is passed at 40--60 DEG C. into isononenyl succinic acid anhydride. The monoamide is converted p into the imide by heating to 150--160 DEG C.; (2) aniline is caused to drop into isododecenyl succinic acid anhydride, the temperature rising to 92 DEG C. The resulting monoanilide is converted to the phenylimide by heating to about 160 DEG C.; (3) n-butylamine is caused to drop into isononenyl succinic acid anhydride, the temperature rising to 100 DEG C. The n - butyl - amino - isononenyl succinic acid formed is converted to the butylimide by heating to 180 DEG C.; (4) ethanolamine is caused to drop into isononylene succinic acid anhydride, the temperature rising to 200 DEG C., isononenyl-succinic acid-b -hydroxy-ethylimide being obtained; (5) isononenyl succinic acid anhydride is caused to drop into melted meta phenylene diamine, a temperature of 180 DEG C. being finally employed. The resulting isononenyl succinic acid-meta-amino-phenylimide is a brown resin; (6) isododecenyl succinic acid anhydride and glycocoll are heated to 140 DEG C. The monoamide formed is converted to isododecenyl succinic acid-imido acetic acid, a dark yellow resin, at about 200 DEG C.; (7) aminophenol and isododecenyl succinic acid anhydride are heated, the temperature rising to 170 DEG C. Isododecenyl succinic acid-parahydroxyphenylimide is obtained as a dark brown viscous resin; (8) isododecenyl-succinic acid anhydride and the sodium salt of sulphanilic acid are heated with stirring. Reaction is complete at 200 DEG C. A bright brown glass is obtained; (9) isododecenyl succinic acid anhydride and the sodium salt of b -amino ethane sulphonic acid are heated, the temperature being raised to 210 DEG C.; (10) freshly distilled N-ethylaniline is run into isononenyl succinic acid anhydride, the temperature being raised to 100 DEG C. The reaction product is neutralized with dilute caustic soda lye, and the solution evaporated to dryness. The sodium salt of N - phenyl - N - ethylamido - isononenyl succinic acid formed is a bright brown glass. By acidifying the aqueous solution of the salt the corresponding acid is obtained; (11) a mixture of isononenyl succinic acid anhydride, diethylamine and Tonsil is boiled under reflux. The mixture is then filtered, and the filtrate distilled first under ordinary, then under reduced pressure. Isononenyl succinic acid diethylamide is obtained; (12) isononenyl succinic acid and N-ethylaniline are heated to 200 DEG C. N - phenyl - N - ethyl - mono - amidoisononenyl succinic acid is obtained; (13) isononenyl succinic acid and p-toluidine are heated at 230 DEG C. The crude isononenyl-succinic acid-p-tolyl-imide is distilled in vacuum.ALSO:Succinic acids substituted in one of their methylene groups by one saturated or unsaturated hydrocarbon residue containing at least five carbon atoms are reacted with nitrogen compounds containing at least one hydrogen atom combined to a nitrogen atom. Amides or imides are obtained. The acids may be replaced by their anhydrides or chlorides. Suitable acids are the products obtained according to Specification 441,016, [Group IV], or by the condensation of olefines such as n-decylene, n-dodecylene, or n-octadecylene, or of polymerization products of olefinic nature with a -b -unsaturated dicarboxylic acid anhydrides or compounds which are converted into said anhydrides, in particular, isononenyl- and isopentadecenyl succinic acids, the anhydrides of which are obtained by condensation of isononylenes and isopentadecylenes with maleic acid anhydride. Suitable nitrogen-containing compounds are ammonia, aliphatic or aromatic amines, e.g. monomethylamine, dibutylamine, hydroxy-ethylamine, aniline, ethylaniline, diphenylamine, a -naphthylamine and benzylamine, amines of the alicyclic series, aminocarboxylic acids such as glycocoll and anthranilic acid and aminosulphonic acids such as taurine. Condensation may be carried out in an inert solvent, e.g. benzene, benzine, ligroin, carbon tetrachloride, dioxane. Monamides are generally first formed, and when these contain a hydrogen atom linked to a nitrogen atom, they are converted by heating to the imides. Diamides are generally obtained when considerable excess of the nitrogen-containing compound is used in the presence of an agent which splits off water, e.g. a hydrosilicate such as Tonsil. Products containing p at least one acid group are particularly suitable as setting, emulsifying, etc., agents. Advantageous wetting agents are, for example, those amidocarboxylic acids obtained by condensation of the succinic acids with monomethylamine, dibutylamine, aniline, ethylaniline, a -naphthylamine, bezylamine, cyclohexylamine, and diamides and imides obtained by condensation of the succinic acids with amines containing a further acid group, e.g. glycocoll, aminophenyl acetic acid, anthranilic acid and taurines. Alkali and ammonium salts are suitable. The Specification contains several examples of the preparation of the derivatives of the substituted succinic acids.