METHOD OF PREPARING EXTRACTIVE SUBSTANCES FROM BIRCH BARK Russian patent published in 2007 - IPC C07J53/00 C07J63/00 C08H5/04 

FIELD: natural substances technology.

SUBSTANCE: method of preparing extractive substances from ground birch bark comprises extraction and filtration of precipitated extract. Extraction is effected with extractant condensate sprinkling ground birch bark bed in presence of ascending vapors of the same extractant. Extractant is two-component mixture of water and low-boiling solvent having boiling point below 100°C. Product is isolated by bringing extractant condensate containing dissolved extract with contents of receiver. Once extraction is completed, solvent is removed with live steam.

EFFECT: reduced consumption of extractant, increased degree of extractant regeneration, simplified isolation of product, and reduced fire and explosion risk.

1 tbl, 2 ex