Organic amine impregnated activated carbon
First Claim
1. A breathing gas filter composition providing protection against toxic perfluorocarbons, comprising substantially dry activated carbon and an organic amine impregnant, said organic amine being selected from the group consisting of substituted amines, amides and sulfonamides in an amount of 1.5 to 18% by weight, based on the weight of the carbon and additionally comprising 0.1 to 10% by weight, based on the weight of the carbon of an alkaline hydroxide.
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Abstract
A novel organic amine-impregnated activated carbon composition is disclosed which may be used in breathing gas filters to enhance removal of various toxic perfluorocarbons. Three processes for impregnating activated carbon with organic amines are also disclosed. One of these processes comprises the steps of placing the amine in contact with substantially dry activated carbon, subjecting the carbon and amine to an environment devoid of oxidizing gases or vapors (such as oxygen gas), and then heating the carbon and amine for an extended period while maintaining this oxidizer-free environment. Pretreatment procedures to enhance both the shelf-life and service-life of the amine-impregnated activated carbon are also disclosed.
92 Citations
21 Claims
- 1. A breathing gas filter composition providing protection against toxic perfluorocarbons, comprising substantially dry activated carbon and an organic amine impregnant, said organic amine being selected from the group consisting of substituted amines, amides and sulfonamides in an amount of 1.5 to 18% by weight, based on the weight of the carbon and additionally comprising 0.1 to 10% by weight, based on the weight of the carbon of an alkaline hydroxide.
- 3. A process for impregnating activated carbon with a low vapour pressure organic amine, comprising the steps of placing the amine in contact with substantially dry activated carbon, subjecting the carbon and amine to positive pressure of 1-5 Pa in an oxygen-free inert gas atmosphere and then heating the carbon and amine for an extended period while maintaining the positive pressure of 1-5 Pa in an oxygen-free inert gas atmosphere, including the step of pre-treating the activated carbon with a compound selected from the group consisting of an alkaline hydroxide in an amount of 0.1 to 10% by weight, based on the weight of the carbon, a suitable halogen and a suitable halide salt.
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14. A process for impregnating activated carbon with a solid amine compound, comprising dissolving the amine in a solvent selected from water and organic solvents and adding the amine solution to the activated carbon, including the step of pre-treating the activated carbon with a compound selected from the group consisting of an alkaline hydroxide in an amount of 0.1 to 10% by weight, based on the weight of the carbon, a suitable halogen and a suitable halide salt.
- 15. A breathing gas filter composition providing protection against toxic perfluorocarbons, comprising substantially dry activated carbon and an organic amine impregnant, said organic amine being selected from the group consisting of ethylenediamine, dipropylamine, isopropylamine, aniline, N,N-diethyl-1,4-phenylenediamine, 4-phenylazoaniline, diisopropylamine, diethylamine, diethylenetriamine, diphenylamine, pyrrole, piperidine, triethylamine, triisobutylamine, tricotylamine, N,N-diethylaniline, 4-(4-nitrobenzyl)-pyridine, hexamethyleneamine, monoethanolamine, urea, N,N-dimethylformamide, o-toluenesulfonamide and p-toluenesulfonamide, in an amount of 1.5 to 18 percent by weight, based on the weight of the carbon and additionally comprising 0.1 to 10% by weight, based on the weight of the carbon of an alkaline hydroxide.
Specification