Improvements in Processes for Extracting from Vegetable Matters, Gluosides possessing Colouring or Tanning Properties, and also in the Products resulting from such Processes.

摘要

9932. Oakes, F. J. April 30. Tannins.-To prevent oxidation of the glucosides obtained in the extraction of tannins &c. from vegetable products by leaching, they are brought into contact with carbonic acid while infusing into the aqueous leach under conditions which admit of their combination with the carbonic acid. The leach is preferably saturated with the carbonic acid, which may be injected into the water near the bottom and preferably continuously throughout the extraction, the process being otherwise carried out as usual. Tannins thus produced are free from gallic acid.