ANIMPROVED PROCESS FOR MANUFACTURING TANNIC ACID IN BRIGHT SEMI-TRANSPARENT OR TRANS- 32 LUCENT CRYSTALS OR GRAINS
Year: 1886

page_text: All Improvcu
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Semi-transparent or Translucent Crystals or Grains.
I, Dr. HEINRICH BYк of No. 13 In den Zelten in the City of Berlin, Prussia,
Germany, Chemist, do hereby declare the nature of my Invention for AN "IMPROVED
PROCESS FOR MANUFACTURING TANNIC ACID IN BRIGHT SEMI-TRANSPARENT OR TRANS-
32
LUCENT CRYSTALS OR GRAINS and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement :-
-
My invention relates to an improved process for manufacturing tannic acid, in
bright semi-transparent or translucent crystals or grains.
In practice it has been found that pulverised tannic acid, CHO", such as is
generally known in commerce, is exceedingly hygroscopic and is partially decomposed
and converted, in part, into gallic acid, OH 0, thus materially decreasing the value
of the same. Moist tannic acid readily adhers and the lumps so produced cause much
trouble and annoyance in employing the same and besides this, tannic acid in
powdered form, can be so readily adulterated that it is difficult to detect the
adulteration without subjecting the same to a thorough analysis. In order, therefore,
to protect the public from fraud, it has been found advisable to manufacture tannic
acid in such form that it can be immediately recognised as a pure compound.
This result can be attained, by adding a minute quantity of a material, which is in
no way hindering to or disadvantageous in the application and employment of the
tannic acid and I have now succeeded in producing pure tannic acid which is free
from all disadvantages pertaining to the pulverised tannic acid of commerce, and in
the form of small bright crystals or grains.
In order to produce this crystallised or granulated tannic acid, I dissolve pure
tannic acid in an appropriate solvent and add, before, during or after evaporation,
about five per cent by weight of alcohol to which a certain quantity of glycerine
(about, 0,05 per cent) is added, spread out the evaporated mass for drying on sheets
of zinc or other suitable metal or material, or in other manner. The tannic acid
becomes in a very short time, dry, brittle and bright and can be loosened from the
said sheets in bright, translucent or semi-transparent grains or crystals.

page_text: A similar compound or preparation can be produced by the addition of alcohol
containing more or less glycerine or glycerine alone, gum, saccharine matter, carbo-
hydrate or other body or bodies, substance or substances, which will render tannic
acid, brittle and translucent or semi-transparent.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed, I declare that what I claim is :-
1. The production or manufacture of tannic acid in the form of bright translucent
or semi-transparent grains or crystals, by adding glycerine, glycerine and alcohol,
gum saccharine matter, carbo-hydrate or other appropriate substance or material to a
more or less viscid solution of tannic acid and a solvent, then drying and granulating
the same, substantially as and for the purpose set forth.
2.A new chemical, commercial product, composed of tannic acid which, by adding
glycerine, glycerine and alcohol, gum, saccharine matter, carbo hydrate or an
equivalent of the same, forms, after drying and granulating, bright crystals or grains,
substantially as and for the purpose set forth.
GEO. DOWNING,
Agent for Applicant.