Black sludge

Specially bottled methyl bromide, in an aluminium cylinder under nitrogen pressure, disgorged a black sludge when liquid was discharged. Inversion and venting, to blow free the line, gave a burst of flame from the vent. It is presumed that corrosion of the cylinder produced pyrophoric aluminium alkyls. 

One of the research projects that von Hoffman suggested to his students was an investigation of the possibility of producing quinine from coal tar. Quinine is a valuable drug for the treatment of malaria. Perkin decided to take on this task and tried to convert both allyl toluidine and aniline (coal tar derivatives) into quinine. His experiments failed, but he noticed that an ugly black sludge was left behind on the bottom of the reaction flask in the aniline experiment. Curious about the residue, he added ethanol (ethyl alcohol) to the flask. A beautiful, deep purple solution formed when the sludge dissolved in the alcohol. 

C. under a slight pressure, the trihydroxide is obtained as a black sludge ... 

Hofmann appointed the seventeen-year-old Perkin as his personal assistant and guided him to work on the synthesis of the antimalarial drug quinine. Perkin had his own ideas for the synthesis of quinine and pursued them in his lab at his parents home. During Easter break 1856 Perkin ran a reaction with aniline (a compound derived from coal tar) and potassium dichromate that produced a black sludge. Dissolving the sludge in ethyl alcohol, Perkin found that the solution took on an intense purple color. Instead of synthesizing quinine, Perkin had made the first synthetic dye derived from coal tar mauve. 

In his attempts to make quinine Perkin started with materials obtained from coal tar. However, instead of getting quinine he got red-brown and black sludges. Fortunately Perkins noticed that one of these messes turned a beautiful purple color when dissolved in alcohol or water. Perkin liked the color so much that he was distracted from his original quest to make quinine. In testing the purple solutions, he found he could use them to dye silk and cotton. 

Preliminary studies of the interaction of leachate with natural clay mineral liners, has revealed the development of a black sludge material. The formation of a sulphide sludge at the leachate clay interface is well documented and has been acknowledged to be a significant factor in the blinding of pores and the consequent reduction in the permeability of clay mineral liners (Bisdom et al. 1983 Brune et al. 1991). It is postulated that this material may act as a sink for metals and other contaminants in leachate, by microbially controlled precipitation. Specific micro-organisms exist that are able to reduce sulphates and initiate the precipitation of metal sulphides, in this way (Brune et al. 1991 Watson et al. 1995). 

Initial observations on dismantling the columns revealed a black sludge at the point of entry... 

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