FIELD: chemistry.
SUBSTANCE: described production method of polymerized lactic acid from the fermentative media, containing the following steps; separation of the available biomass and any solid substances from the fermentative medium in at least two consecutive stages; reduction of pH value upto 2.2-2.4 by adding and mixing the concentrated sulfuric acid in the lactic acid solution from the fermentative medium without biomass; separation of the lactic acid solution from the fermentative medium without biomass by using the pseudo-moving layer chromatography (SMB); purification of the separated lactic acid solution by the first stage of ion exchange; the lactic acid solution concentration, purified at the first stage of the ion exchange with the help of the first stage of single or multi-stage evaporation; the additional purification of the pre-concentrated and pre-purified lactic acid solution by the second ion exchange stage; the lactic acid solution concentration, purified at the second ion exchange stage by the second stage of single or multi-stage evaporation. The lactic acid is characterized by the diclactide yield of more than 90% and the racemization less than 5%, in which the preparation of polymerized lactic acid is carried out without distillation. Also the usage of the polymerized lactic acid, produced by the above mentioned method for the polylactides production, is described.
EFFECT: production of the lactic acid, suitable for polymerization, characterized by the high yield of diclactide and low racemization.
16 cl, 2 dwg, 3 tbl, 8 ex
