Manufacture of Chemical Compounds of Starch and Dextrine or Equivalent Bodies with Formaldehyde or its Equivalents.
Year: 1897

page_text: Date of Application, 15th Jan., 1897-Accepted, 20th Mar., 1897
COMPLETE SPECIFICATION.
Manufacture of Chemical Compounds of Starch and Dextrine or
Equivalent Bodies with Formaldehyde or its Equivalents.
1, Dr. ALEXANDER CLASSEN, of Aix-la-Chapelle, Germany, Professor and
Privy State Councillor, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
It has been known for about 8 years that formaldehyde, even in the most diluted
solutions, possesses in a high degree the property of energetically retarding the
development of bacteria, or even of killing them. This property, combined with
only slightly poisonous effect, has already rendered formaldehyde a valued
preservative and antiseptic medium, which can be used with great advantage.
For the antiseptical treatment of wounds however, neither the free formaldehyde
nor its polymeric combinations, para-aldehyde, trioxymethylene, could be employed,
as according to experiments made (Aronson, Berl. Klin. Wochenschrift 1892
No. 29) it had too great an irritating action. With the chemical combinations of
formaldehyde which are required to decompose gradually under the action of the
tissues and secretions, with splitting off of formaldehyde, the body bound with the
formaldehyde must cause no detrimental subsidiary action.
:
I have now found that starch of any description and meal containing starch, also
starch-like substances such as dextrine, bassorine, carraghen-mucilage, agar-agar,
fermentation-gum, galactin, inuline, lævulan, lichenine &c., and algae and lichens
containing these, also gums such as gum arabic, and the like, plant mucilages, also
pectine substances, combine with formaldehyde under definite conditions to form
chemical compounds, whereby definite and permanent new compounds are produced
which are entirely different from the original substances as regards their physical
and chemical properties.
I
The mode of manufacture of these new chemical compounds is shewn in the
following examples.
1) 5 kilos. starch of any kind such as potato-wheat-maize, rice-starch, arrowroot-
flour, are mixed, in a vessel capable of air tight closure, such as a digester, with ap
excess of 40 p.c. formaldehyde solution, i.e. from 1.5 to 2 litres; the mixture is
stirred and the hermetically closed vessel is subjected for from 5 to 6 hours to a
temperature of from 100 to 120° C. After cooling, the mass, which still contains
much free formaldehyde, is removed from the vessel and is then again heated for
about 24 hours to 120° C., for effecting a farther reaction of the formaldehyde upon
the starch. The mass obtained is then finely powdered and is again stirred together
with from 15 to 2 litres formaldehyde, and the above described manipulation is
repeated. For the removal of the still existing free formaldehyde in the product
obtained, this is treated with water or other solvent for formaldehyde, and is finally
dried at 100° C.
2) 3 kilos. starch are mixed to a paste with 3 litres formaldehyde, and the paste
is dried in vacuo under withdrawal of the vapours; it is then heated for 24 hours
to 124° C. for the reaction of the excess of formaldehyde upon the starch. The
mass obtained is powdered and again stirred together with formaldehyde and the

page_text: described process is repeated. The separation from the free formaldehyde still
present is effected as described under (1).
3) 3 kilos. starch are mixed with 0.5 kilos. trioxymethylene.
As at ordinary temperature and even at temperatures between 50° and 80° C. no
reaction ensues between these bodies, the mixture must be heated to 120° C. for
about 24 hours for producing a chemical combination between the formaldehyde
and the starch which coincides in its properties with the compounds described under
(1) and (2), and the described manipulation with trioxymethylene is again repeated.
The compound obtained is purified as described under (1).
If starch soluble in water be mixed with formaldehyde in the above stated
proportions, and the mixture be heated in a digester to 90° to 100° C., there will be
obtained a chemical combination of formaldehyde with starch soluble in water.
For freeing the same from excess of formaldehyde, the aqueous solution is poured
into alcohol, whereby the formaldehyde starch will be separated.
After washing with alcohol it is dried at a temperature of 80° to 90° C.
4) 3 kilos. dextrine (arabine, inuline) are dissolved in 1.5 litres formaldehyde of
40 p.c. at from 90° to 100° C.; the syruppy mass is heated for 24 hours to from
120° to 130° C. and the described manipulation is repeated after pulverising the
mass.
The purification is effected as uuder (1) with arabine the reaction is easily
effected; with dextrine less casily ; and with inuline only very gradually..
For the production of formaldehyde-compounds of starch-like bodies soluble in
water, the process described under (3) for starch can be adopted.
5) 1 kilo. of a 20 p.c. solution of carraghen mucilage (quince-mucilage, agar-
agar) is mixed with 200 cube cm. formaldehyde and is evaporated to dryness on a
vapour bath; the compound is then heated for 24 hours to 120° C. and treated as
under (1).
6) 100 parts lichenin are stirred together with 100 parts formaldehyde to form a
paste, the compound is then heated for 24 hours to 120° C., and is purified us
under (1).
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. Manufacture of compounds of starch and starch-like bodies (dextrine, gums,
pectine bodies and the like) with formaldehyde by causing the said substances, or
the algae or lichens containing the same, to react with formaldehyde either at
ordinary temperature or at a higher temperature, and if necessary under pressure,
the reaction product obtained, which contains free formaldebyde, being heated for
24 hours to 120° C., for effecting a farther reaction of the bodies, after which the
compounds are again treated in the above described manuer with formaldehyde and
then with water or other solvent of formaldehyde, for the removal of the free
portions thereof, and are finally dried.
2. The modification of the process set forth in the first claim, consisting in the
substitution for the formaldehyde of substances yielding or splitting off formaldehyde
or of compounds analogous to formaldehyde or methylen-glykol, substantially as
described.
3. As new manufactures, compounds consisting of starch of any kind, or of meal
containing starch, or of starch-like bodies (dextrine bassorine, carraghen-mucilage
agar-agar, fermentation-gum, galactin, inuline, lævulan, lichenine &c. as also the
algæ and lichens containing these bodies) or of gums (arabine and other gums,
plant-mucilages) or of pectine bodies, in chemical combination with formaldehyde,
substantially as described.
4. The herein described process for the production of chemical combinations of
starch, starcb-like substances, gum or pectine-bodies with formaldehyde or the like,
consisting in bringing the said bodies together under pressure so as to effect a
chemical reaction of the starch or other body with the formaldehyde or equivalent

page_text: body and then freeing the product from the excess of formaldehyde or equivalent.
body substantially as described.
T
1001
ABEL & IMRAY,
Agents for the Applicant.