GB832423A - Process for the analysis of gaseous hydrocarbons - Google Patents

Abstract

Gaseous mixtures of unsaturated hydrocarbons either alone or in admixture with saturated hydrocarbons are hydrogenated and then gas-chromatographed using hydrogen as a carrier gas to analyse the content of the mixture. The gas mixtures which contain saturated hydrocarbons can be treated with an absorbent to remove the unsaturated hydrocarbons and then chromatographed in order to arrive at the final result but in certain specified cases the absorption step is unnecessary. The hydrocarbons are generally separated as methane, ethane, propylene, isobutane, n-butane, isopentane, n-pentane and cyclopentane, n-hexane, 2-methyl pentane, 3-methyl pentane, 2 : 2-dimethyl butane, 2 : 3-dimethyl butane. A hydrogenation catalyst comprises kieselguhr with a grain size of 0.3 to 0.4 mm. on which platinum has been precipitated by impregnating the kieselguhr with 1/10 molar platinum tetrachloride solution and then reducing the tetrachloride with hydrazine hydrate to give a platinum content of 0.6%. Alternatively a palladium compound such as the palladium dichloride may be used as may weaker solutions of the noble metals. An olefine absorbent comprises kieselguhr which has been impregnated with 50% by weight of a solution of 5% silver sulphate in concentrated sulphuric acid. As an alternative to the kieselguhr an aluminium oxide containing kieselguhr containing about 72% silica, 10% alumina, 1% titania, 10% ferric oxide, 2.4% calcium oxide, 1.5% magnesia, 3.7% water and 1.5% sodium oxide is used.ALSO:Gaseous mixtures of unsaturated hydrocarbons either alone or in admixture with saturated hydrocarbons are hydrogenated and then gas chromatographed using hydrogen as a carrier gas to analyse the content of the mixture. The gas mixtures which contain saturated hydrocarbons can be treated with an absorbent to remove the unsaturated hydrocarbons and then chromatographed in order to arrive at the final result, but in certain specified cases the absorption step is unnecessary. The hydrocarbons are generally separated as methane, ethane, propylene, isobutane, n-butane, isopentane, n-pentane and cyclopentane, n-hexane, 2-methyl pentane, 3-methyl pentane, 2:2-dimethyl butane, 2:3-dimethyl butane. A hydrogenation catalyst comprises kieselguhr with a grain size of 0.3 to 0.4 mm. on which platinum has been precipitated by impregnating the kieselguhr with 1/10 molar platinum tetrachloride solution and then reducing the tetrachloride with hydrazine hydrate to give a platinum content of 0.6%. Alternatively, a palladium compound such as the palladium dichloride may be used as may weaker solutions of the noble metals. As an alternative to the kieselguhr, an aluminium oxide containing kieselguhr containing about 72% silica, 10% alumina, 1% titania, 10% ferric oxide, 2.4% calcium oxide, 1.5% magnesia, 3.7% water and 1.5% sodium oxide is used.