[Calculation of a single and of subsequent extraction-reextraction cycles].

Estimation of the equilibrium distribution in the organic solvent-water system provided analysis of efficiency and optimal arrangement of subsequent extraction-reextraction cycles in isolation of various compounds. The analysis was performed with respect to optimization of the total yield and required volumes of the intermediate phases. It was shown that the best arrangement of the subsequent extraction-reextraction cycles depended on the compound distribution coefficients at various stages.

[Benzylpenicillin interaction with amines in the organic phase].

Benzylpenicillin interaction with amines in the nonaqueous phase was studied by pH dependence of the coefficient of the antibiotic distribution in the system of amine butyl acetate solution--water. A distribution scheme involving interaction of the amine molecular and cationic forms with benzylpenicillin and amine dissociation equilibrium in organic solution is described. On the basis of the experimental data the interaction and dissociation constants were determined for a number of aromatic and aliphatic amines.

[Mathematical model of removal of impurities from antibiotic pastes].

The process of antibiotic paste washing by repulpation in a solvent, as well as the process of replacing washing of antibiotic filter cakes was studied. This enabled to develop a mathematical model of the process of admixture removing from antibiotic pastes by successive repulpation and replacing washing. The model connects the initial admixture levels in pastes, the filter cake characteristics, the specification requirements to the drug quality and the technological parameters of the process.

[Separation of emulsions during extraction of antibiotics from native solutions].

The separating capacity of a laboratory cup centrifuge and industrial centrifugal separator was compared. It was shown that the process of emulsion centrifugal separation could be modeled under laboratory conditions: antibiotic fermentation broth filtrate--organic solvent in industrial apparatus under similar conditions of preliminary mixing aqueous and organic phases.

[Hydrodynamic study of a centrifugal differential-contact extractor].

Centrifugal extractors of the differential-contact type are widely used all over the world in production of antibiotics. Lately, new extractors were developed by Hitachi (Japan). Model E is of a special interest.