GB648099A - Steam generation and compositions for inhibiting foaming - Google Patents

Abstract

Monoethers of polyoxyalkylene glycols having a molecular weight of at least 500 and in which the hydroxy and ether groups are attached to different terminal carbon atoms are prepared by (1) reacting the appropriate alkylene oxide or mixture of alkylene oxides with a monohydric alcohol, or (2) reacting alkyl or aryl halides with the appropriate alkali metal alcoholate. The alkylene radical is preferably ethylene or propylene but polyalkylene chains containing both ethylene and propylene groups may be produced. The ether groups may be derived from monohydric alcohols or monobasic phenols, e.g. methanol, ethanol, propanol, isopropanol, butanols, cetyl alcohols, octadecanol, cyclohexanols, phenols, cresol, benzyl alcohol, or from monohydric alcohols or phenols having substituent groups, e.g. halogeno, nitro, cyano, alkyl and alkoxy groups, in the hydrocarbon chain or aromatic ring. Examples are given of the preparation of the monobutyl, monolauryl and monocetyl ethers of polyoxyethylene glycol, the monocetyl, monophenyl, monocyclohexyl and monobenzyl ethers of polyoxypropylene glycol and the monobutyl ether of polyoxyethylene-oxypropylene glycol. The compounds are employed as foam-inhibiting agents.ALSO:The formation of foam in steam generators is minimized by the addition to the boiler water of a monoether of a polyoxyalkylene glycol having a molecular weight of at least 500, and in which the hydroxy and ether groups are attached to different terminal carbon atoms. The alkylene radical is preferably ethylene or propylene, but polyalkylene chains containing both ethylene and propylene radicals may be employed. The ether groups may be derived from monohydroxy alcohols or monobasic phenols, e.g. methanol, ethanol, propanol, isopropanol, the butanols, cetyl alcohol, octadecanol, cyclohexanols, phenol, cresol, benzyl alcohols, or from monohydric alcohols or phenols having substituent groups, e.g., halogeno, nitro, cyano, alkyl and alkoxy groups, in the hydrocarbon chain or aromatic ring. The foam-inhibiting agents, of which numerous examples are given, may be employed in admixture with dispersants, e.g. tannin, sodium lignin sulphonate, desulphonated lignin, sulphated oils, soaps of oleic acid or tall oil, soda ash, orthophosphates and polyphosphates in the form of powdered or briquetted compositions. To nullify the effects of magnesium salts in the water, hydroxylated organic materials such as tannic acid, gallic acid, pyrogallol, catechol and phloroglucinol may be incorporated in the compositions.