Patent GB-433398-A (GB)
Title: A process of removing hydrocyanic acid from mixtures containing the same
IPC: C01C3/04
Filed: 1934-06-13
Abstract: Hydrocyanic acid is recovered from mixtures containing the same, e.g. gaseous or liquid mixtures, by treating the mixtures with a solvent of the class consisting of ethers, esters and mixed ether-esters of monoglycols (e.g. polyglycols), or of polyglycols including their cyclic compounds.  The resulting solutions of hydrocyanic acid may be used in reactions employing hydrocyanic acid such as condensation reactions with aldehydes, ketones, oxides or the like.  Suitable solvents include polyglycols such as diethylene glycol, dipropylene glycol, dibutylene glycol, triethylene glycol, ethylene propylene glycol, ethylene butylene glycol, propylene butylene glycol, diethylene butylene glycol, propylene isobutylene glycol, ethylene isobutylene glycol, ethers and esters of polyglycols such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, diethylene glycol mono-isopropyl ether, diethylene glycol monotertiary butyl ether, diethylene glycol mono- or dilactate, benzoate, acetate, maleate or oxalate, diethylene glycol mono-ethyl ether formate, diethylene glycol mono-isopropyl ether benzoate, diethylene glycol mono-tertiary butyl ether acetate, diethylene glycol monophenyl ether acetate, diethylene glycol mono-ethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monobutyl ether acetate, mono-glycol compounds such as glycol monoformate, glycol mono-and di-alkyl ethers, esters of mono-alkyl ethers of glycol, ethylene glycol mono-ethyl ether, ethylene glycol mono-ethyl ether acetate, and cyclic derivatives such as cyclic ethers and oxides, e.g. dioxane, and their homologues.  The Specification as open to inspection under Sect. 91 describes also the employment of the esters or ethers of other polyhydric alcohols, e.g. glycerol mono- and di-acetate, mono-, di-and tri-alkyl ethers of glycerol, esters of the mono- or di-alkyl ethers of glycerol, glycidol or its ethers and esters.  This subject-matter does not appear in the Specification as accepted.ALSO:Hydrocyanic acid is recovered from mixtures containing the same, e.g. gaseous or liquid mixtures, by treating the mixtures with a solvent of the class consisting of ethers, esters and mixed ether-esters of monoglycols (e.g. polyglycols) or of polyglycols including their cyclic compounds.  Gases containing hydrocyanic acid may be brought into contact with these solvents at atmospheric or increased pressure, the hydrocyanic acid being recovered by heating and/or reducing the pressure.  Liquid phase extraction may also be employed.  Hydrocyanic acid may also be dissolved under pressure in a porous mass wetted with one or more of the solvents.  Gas mixtures containing hydrocyanic acid obtained from formamide, ammonia and carbon monoxide, hydrocarbons and ammonia, or hydrocarbons and nitric oxide may be treated, for example the gas mixture obtained by passing a mixture of natural gas and the catalytic oxidation products of ammonia over heated silica gel.  The resulting solutions of hydrocyanic acid may be used for storage or in reactions employing hydrocyanic acid such as condensation reactions with aldehydes, ketones, oxides or the like.  Suitable solvents include polyglycols such as diethylene glycol, dipropylene glycol, dibutylene glycol, triethylene glycol, ethylene propylene glycol, ethylene butylene glycol, propylene butylene glycol, diethylene butylene glycol, propylene isobutylene glycol, ethylene isobutylene glycol, ethers and esters of polyglycols such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-propyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene gylcol dipropyl ether, diethylene glycol dibutyl ether, diethylene glycol mono-isopropyl ether, diethylene glycol mono-tertiary butyl ether, diethylene glycol mono- or di-, lactate, benzoate, acetate, maleate or oxalate, diethylene glycol monoethyl ether formate, diethylene glycol monoisopropyl ether benzoate, diethylene glycol mono-tertiary butyl ether acetate, diethylene glycol monophenyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-propyl ether acetate, diethylene glycol monobutyl ether acetate, mono-glycol compounds such as glycol monoformate, glycol mono- and di-alkyl ethers, esters of monoalkyl ethers of glycol, ethylene glycol monoethyl ether, ethylene glycol mono-ethyl ether acetate, and cyclic derivatives such as cyclic ethers and oxides, e.g. dioxane, and their homologues.  The Specification as open to inspection under Sect. 91 describes also the employment of the esters or ethers of other polyhydric alcohols, e.g. glycerol mono- and di-acetate, mono-, di-, and tri-alkyl ethers of glycerol, esters of the mono- or di-alkyl ethers of glycerol, glycidol or its ethers and esters, and the employment of the polyhydric alcohol derivatives for removing the other common acidic components such as hydrogen sulphide, sulphur dioxide, carbon dioxide and carbon monoxide from natural and industrial gas mixtures containing them.  This subject-matter does not appear in the Specification as accepted.