AT28487B - Process for decolorizing tannin extracts. - Google Patents

Process for decolorizing tannin extracts.

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Publication number
AT28487B
AT28487B AT28487DA AT28487B AT 28487 B AT28487 B AT 28487B AT 28487D A AT28487D A AT 28487DA AT 28487 B AT28487 B AT 28487B
Authority
AT
Austria
Prior art keywords
decolorizing
extracts
tannin extracts
tannin
formaldehyde
Prior art date
Application number
Other languages
German (de)
Original Assignee
Basf Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Basf Ag filed Critical Basf Ag
Application granted granted Critical
Publication of AT28487B publication Critical patent/AT28487B/en

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  • Treatment And Processing Of Natural Fur Or Leather (AREA)

Description

  

   <Desc/Clms Page number 1> 
 



  Verfahren zur Entfärbung von Gerbstoffextrakten. 



   Die aus gerbstoffhaltigen Rinden gewonnenen Extrakte sind in vielen Fällen so stark gefärbt, dass ihre direkte Verwendung für Zwecke der Ledergerbung ausgeschlossen ist, da sie das Material anfärben. Bisher hat man sich damit beholfen, die Extrakte mit schwefliger Säure zu behandeln, dieses   Mitte !   versagte aber in vielen Fällen und lieferte keine den Anforderungen genügende oder keine bleibende   Entfärbung.   



   Es wurde nun gefunden, dass man mit Hilfe von Formaldehydsulfoxylaten entweder in reiner Form oder in Verbindung mit Formaldehydbisulfiten wesentlich bessere Effekte erzielt als mit   schwefliger Säure   und in ausgezeichneter   Weise die Entfärbung von Gcrbstoff-   extrakten erreicht, wenn man die erwähnten Substanzen in der Wärme auf die wässerigen Extrakte einwirken lässt. Am geeignetsten ist es, die Einwirkung beim Eindicken des Extraktes vor sich gehen zu lassen. 



   Während bei der Behandlung mit Reduktionsmitteln wie Bisulfit die Farbe nicht 
 EMI1.1 
 und nach einiger Zeit wiederkehren, wird nach diesem   Verfahren eine vollständige Zer-   störung und eine dauernde Entfärbung erzielt. 



   Beispiel : 
 EMI1.2 
 



  (zirka 90%iges Formaldehydrnatriumsulfoxylat) versetzt und im Vakuum zur Trockene verdampft. 

**WARNUNG** Ende DESC Feld kannt Anfang CLMS uberlappen**.



   <Desc / Clms Page number 1>
 



  Process for decolorizing tannin extracts.



   The extracts obtained from tannin-containing bark are often so strongly colored that their direct use for leather tanning purposes is ruled out, as they stain the material. So far one has managed to treat the extracts with sulphurous acid, this middle! but failed in many cases and did not meet the requirements or provided no permanent discoloration.



   It has now been found that with the aid of formaldehyde sulfoxylates, either in pure form or in conjunction with formaldehyde bisulfites, significantly better effects are achieved than with sulphurous acid, and the decolouration of dye extracts is achieved in an excellent way if the substances mentioned are heated to the heat watery extracts to act. It is most suitable to let the action go by while thickening the extract.



   While when treated with reducing agents such as bisulfite the color does not
 EMI1.1
 and after some time they return, this process results in complete destruction and permanent discoloration.



   Example:
 EMI1.2
 



  (about 90% sodium formaldehyde sulfoxylate) added and evaporated to dryness in vacuo.

** WARNING ** End of DESC field may overlap beginning of CLMS **.

 

Claims (1)

PATENT-ANSPRUCH : Verfahren zur Entfärbung von Gerbstofextrakten, dadurch gekennzeichnet, dass man dieselben mit Formaldehydsuifoxylaten in reifer Form oder in Verbindung mit Formaldehydhisulfiten behandelt. **WARNUNG** Ende CLMS Feld Kannt Anfang DESC uberlappen**. PATENT CLAIM: Process for decolorizing tannin extracts, characterized in that they are treated with formaldehyde sulfoxylates in ripe form or in combination with formaldehyde hisulfites. ** WARNING ** End of CLMS field may overlap beginning of DESC **.
AT28487D 1906-02-05 1906-02-05 Process for decolorizing tannin extracts. AT28487B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT28487T 1906-02-05

Publications (1)

Publication Number Publication Date
AT28487B true AT28487B (en) 1907-05-25

Family

ID=3541247

Family Applications (1)

Application Number Title Priority Date Filing Date
AT28487D AT28487B (en) 1906-02-05 1906-02-05 Process for decolorizing tannin extracts.

Country Status (1)

Country Link
AT (1) AT28487B (en)

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