GB568510A - Anti-foam agents - Google Patents

Abstract

Foaming during the generation of steam from water is prevented by adding to the water a small proportion of one or more substances whose formula may be represented by <FORM:0568510/IV/1> where RCO represents an aliphatic acid radicle preferably having at least 14 carbon atoms, X represents an aliphatic or aromatic group which may be interrupted or substituted with one or more amine or amide groups but is free from CO groups or X may be absent altogether; Y represents hydrogen or an aromatic or aliphatic acid radicle attached either directly to the N atom or through other atoms; Z and Z1 are hydrogen, or are together -C2H4- in which case X is also -C2H4-; the total number of carbon atoms in the substance being at least 18, at least 24 if it is derived from polyalkylene diamines or piperazine, or at least 26 if it is derived from alkylene diamines. R.CO may represent the radicle of fatty acids or such acids as erucic acid, hydroxystearic acid or dibromricinabaic acid. The substances in question include N,N1-dioleyl hydrazine, N,N1-distearyl ethylene diamine, N,N1 - acetyl palmityl triethylene tetramine, monostearyl tetraethylene pentamine, monocerotyl hydrazine, and the substances prepared according to the examples in which (1) a mixture of oleic acid and diethylenetriamine is heated at 150-160 DEG C.; (2) formaldehyde solution is slowly added to stearamide heated to 175 DEG C.; (3) trioxymethylene is slowly added to palmitamide or stearamide heated to 150-160 DEG C.; (4) a mixture of castor oil and triethylenetetramine is heated at 150-160 DEG C.; (5) a mixture of decamethylenediamine and myristic acid is heated at 150-160 DEG C.; (6) a mixture of stearic acid and m-phenylenediamine is heated at 150-160 DEG C.; (7) benzidine is slowly added to palmityl chloride at a temperature progressively increasing from 100 DEG C. to 250 DEG C.; (8) a mixture of stearic acid and hydroxyethylethylene diamine is heated at 150-160 DEG C.; (9) stearyl chloride is heated with 1,3-diaminopropanol at 150-160 DEG C.; (10) dilauryldiethylenetriamine is condensed with acetyl chloride at a temperature of 150-160 DEG C.; (11) diethylenetriamine and ethylene chloride are slowly and simultaneously added to dioleyldiethylenetriamine heated to 150-160 DEG C., the product obtained being further acylated by heating with stearyl chloride at 150-160 DEG C.; (12) monostearylhydrazine is condensed with 5-dichloroacetone at a temperature of 150-160 DEG C.; (13) a dehydrated mixture of commercial stearic acid and piperazine hexahydrate is heated with p-toluene sulphonyl chloride. The above mentioned substances may be dispensed or admixed with sodium carbonate or other material used for treating water; or they may be dissolved in organic water-miscible solvents such as alcohols, ethers or ketones, or emulsified in water with the aid of non-foaming emulsifying agents, with or without the addition of sodium carbonate and in these forms added to the water. They may be used with other known anti-foaming agents such as castor oil, or along with other materials used in water treatment such as chestnut tannin or gallic acid. They should preferably be added to the water after it has been treated to remove hardness and after the removal of the precipitated hardness forming constituents. A statement of prior knowledge refers to the known anti-foaming properties of castor oil, tallow, turkey red oil, fatty acid amides, and high molecular weight primary, secondary and tertiary alkyl or aryl amines.