CREOSOTE IMPURITIES.
[Footnote: Read at the meeting of the American Pharmaceutical Association held at Niagara Falls. 1882.]
By Prof. P. W. BEDFORD.
The object of this query can be but one, namely, to inquire whether the wood creosote offered for sale is a pure article, or not; and if not, what is the impurity present?
The relative commercial value of the articles sold as coal tar creosote and wood creosote disposes of the question as to the latter being present in the former article, and we are quite certain that the cheap variety is nothing more or less than a phenol or carbolic acid. Wood creosote, it has been frequently stated, is adulterated with coal tar creosote, or phenol. The object of my experiments has been to prove the identity of wood creosote and its freedom from phenol. The following tests are laid down in various works as conclusive evidence of its purity, and each has been fully tried with the several samples of wood creosote to prove their identity and purity, and also with phenol, sold as commercial creosote or coal tar creosote, and for comparison with mixtures of the two, that even small percentages of admixture might be identified, should such exist in the wood creosote of the market.
The following tests were used:
1. Equal volumes of anhydrous glycerine and wood creosote make a turbid mixture, separating on standing. Phenol dissolves. If three volumes of water be added, the separation of the wood creosote is immediate. Phenol remains in permanent solution.
2. One volume of wood creosote added to two volumes of glycerine; the former is not dissolved, but separates on standing. Phenol dissolves.
3. Three parts of a mixture containing 75 per cent, of glycerine and 25 of water to 1 part of wood creosote show no increase of volume of glycerine, and wood creosote separates. Phenol dissolves, and forms a clear mixture. Were any phenol present in the wood creosote, the increase in the volume of the glycerine solution, if in a graduated tube, would distinctly indicate the percentage of phenol present.
4. Solubility in benzine. Wood creosote entirely soluble. Phenol is insoluble.