GB645928A - Improvements in and relating to the extraction of organic compounds dissolved in water - Google Patents

Abstract

In extracting an organic substance dissolved in water, a hydrophobic solid is saturated with a water-immiscible solvent for the organic substance, the solvent being one which does not dissolve the hydrophobic solid but swells it, and the swollen solid is employed as an adsorbent for extracting the organic substance from an aqueous solution thereof having a suitable pH value. Specified adsorbents are vulcanized rubber swollen by contact with chloroform or polyvinyl chloride swollen by contact with tetrachloroethane, chloroform, chlorobenzene, o-dichlorobenzene, or a mixture of equal parts of methylcyclohexanol and methylcyclohexanol. The organic substance can be re-extracted from the adsorbent by contact with an aqueous liquid of suitable pH value. According to an example, the adsorbent is prepared by pouring a hot solution of polyvinyl chloride in a mixture of tetrachloroethane and pentachloroethane through a column of charcoal. A solution of extractive matter from hyoscyamus muticus is adjusted to pH 9.7 by the addition of milk of lime and is filtered. The solution is then passed downwards through the column followed by a washing of distilled water and N / 50 sulphuric acid. As the sulphuric acid passes through the column the pH decreases steadily to 1.8. The fraction collected between pH 9.0 and 5.6 contains hyoscyamine but substantially no other alkaloid. That collected between pH 5.6 and 1.8 contains all the hyoscine and only a small proportion of the hyoscyamine. Pumice may be used instead of charcoal in the preparaation of a column. When not in use the unoccupied space in the column is filled with brine.ALSO:In extracting an organic substance dissolved in water, a hydrophobic solid is saturated with a water-immiscible solvent for the organic substance, the solvent being one which does not dissolve the hydrophobic solid but swells it, and the swollen solid is employed as an adsorbent for extracting the organic substance from an aqueous solution thereof having a suitable pH value. Specified absorbents are vulcanized rubber swollen by contact with chloroform or polyvinyl chloride swollen by contact with tetrachloroethane, chloroform, chlorobenzene, o-dichlorobenzene, or a mixture of equal parts of methylcyclohexanol and methylcyclohexanol. The organic substance can be re-extracted from the adsorbent by contact with an aqueous liquid of suitable pH value. According to an example, the adsorbent is prepared by pouring a hot solution of polyvinyl chloride in a mixture of tetrachloroethane and pentachloroethane through a column of charcoal. A solution of extractive matter from hyoscyamus muticus is adjusted to pH 9.7 by the addition of milk of lime and is filtered. The solution is then passed downwards through the column followed by a washing of distilled water and N/50 sulphuric acid. As the sulphuric acid passes through the column the pH decreases steadily to 1.8. The fraction collected between pH 9.0 and 5.6 contains hyoscyamine but substantially no other alkaloid. That collected between pH 5.6 and 1.8 contains all the hyoscine and only a small proportion of the hyoscyamine. Pumice may be used instead of charcoal in the preparation o fa column. When not in use the unoccupied space in the column is filled with brine.