cover image: Government of Bengal  Bengal Industrial Research Board  Department of Industries  Bulletin No. 80  Examination of Indian Tannin Materials with Reference to Ink Manufacture  The Preparation of Gallic and Tannic Acid from Touri (Caesalpinia Dignya)

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Government of Bengal Bengal Industrial Research Board Department of Industries Bulletin No. 80 Examination of Indian Tannin Materials with Reference to Ink Manufacture The Preparation of Gallic and Tannic Acid from Touri (Caesalpinia Dignya)

1942

From the point of view of the ink maker the tannins may be roughly divided into two groups—the iron blueing tannins and the iron greening tannins —of which the latter variety is of little use to the ink maker. [...] As the fermentation proceeds the percentage of gallic acid increases and some of the tannin astringents originally present in the raw material is lost during the process. [...] During the period the composition of the extract is slightly changed and it is advisable to know the contents of the astringent acids by analysis. [...] The chemical change is not properly understood but it points to the formation of a little oxidised ink which with the bulk of the ink separates small quantities of precipitates and at the same time a complexity in the ink composition is set up. [...] If the addition of salt is continued to the filtered extract until a permanent precipitate of tannic acid is formed and the filtrate after the separation of precipitated tannic acid is extracted with ethyl acetate a better and paler tannic acid is obtained.
technology medicine science
Pages
15
Published in
India
SARF Document ID
sarf.144024
Segment Pages Author Actions
Frontmatter
i-i R.L. Datta, Susthir Sen, Lakshmi Dey view
Government of Bengal Bengal Industrial Research Board Department of Industries Bulletin No. 80 Examination of Indian Tannin Materials with Reference to Ink Manufacture The Preparation of Gallic and Tannic Acid from Touri (Caesalpinia Dignya)
1-12 R.L. Datta, Susthir Sen, Lakshmi Dey view
Appendix
13-14 R.L. Datta, Susthir Sen, Lakshmi Dey view

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