Observations sur l'action détersive des solutions de savon : Première communication

Spring, W. Bulletin de la Classe des Sciences, Academie Royale de Belgique (1909), 187-206; SciFinder (Chemical Abstracts Service: Columbus, OH); https://scifinder.cas.org (accessed July 8, 2010).

Lampblack purified from fats and resins was tested for its rate of sedimentation in pure H2O, in 0.01-2% soap solns., in 0.01-2% soap solns. containing an equivalent of HCl or of KOH, and in MeOH or EtOH solns. of soap, the concentrations of soap being 1/50 and 1/60% in the MeOH and 0.02% in the EtOH. In H2O and in 2% soap soln. lampblack remained in suspension to the same extent; in 0.5% soap soln. in 6 days a small amount of lampblack remained in suspension; in I% soap soln. lampblack remained in suspension for more than 2 mos. In all cases some of the lampblack was deposited. The acid solns. in the different concentrations cleared quickly, while the alkaline solns. held the lampblack in suspension better than H2O. The alcohols acted as H2O, but to produce an effect of the same order, their mass ought to be 50-200 times as great as that of H2O. The soap soln. shaken with lampblack gave a heavier ash than the soap soln. alone. The soln. seemed to be divided into 2 parts, a more acid one which agglutinated with the lampblack and a more basic one which remained in the soln. Proof of this was found from the smaller ash remaining from the residue after treating in alc. The alc. solns. gave less of a detergent effect. The sediment of lampblack in the soap soln. differed from that in H2O by being viscous and oily while that in H2O was grainy and easily thrown into suspension in H2O. On filtration the lampblack from H2O suspensions blackened the paper completely while from soap soln. the particles not in contact with the paper were readily detached. Lampblack in pure H2O with a current of 8 volts did not conduct; in H2O rendered slightly alkaline the lampblack was deposited at the cathode; in a 2% soap soln. after some hrs. lampblack was deposited at the anode.

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