Synthetic Tannins: Their Synthesis, Industrial Production and Application

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D. Van Nostrand Company, 1922 - 143 pages
 

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Page 84 - In the case of tans it must be clearly stated in the report whether the calculation is on the sample with moisture as received, or upon some arbitrarily assumed percentage of water ; and in that of liquors whether the percentage given refers to weight or to grams per 100 c.cs.
Page 80 - C., and the extraction continued with boiling water till the filtrate amounts to 1 litre. It is desirable to allow the material to soak for some hours before commencing the percolation, which should occupy not less than 3 hours, so as to extract the maximum of tannin. Any remaining solubles in the material must be neglected or reported separately, as " difficultly soluble
Page 82 - ... of water and must be sufficiently free from soluble organic matter to render it possible in the ordinary washing to reduce the total solubles in a blank experiment with distilled water below 5 grm.
Page 79 - ... cm. deep in a beaker, placed in a good light on black glass or black glazed paper, must appear dark and free from opalescence when viewed from above. Any necessary mode of filtration may be employed, but if such filtration causes any appreciable loss when applied to a clear solution, a correction must be determined and applied as described in paragraph 6.
Page 80 - Sumach and myrobalans extracts should be dissolved at a lower temperature. Solid extracts shall be dissolved by stirring in a beaker with successive quantities of boiling water, the dissolved portions being poured into a litre flask, and the undissolved being allowed to settle and treated with further portions of boiling water. After the whole of the soluble matter is dissolved the solution is treated similarly to that of a liquid extract. Solid tanning materials, previously ground till they will...
Page 82 - The moisture in the air-dried powder is estimated and the quantity equal to 6.5 grm. actual dry hide powder is calculated, which will be practically constant if the powder be kept in an air-tight vessel. Any multiple of this quantity is taken according to the number of analyses to be made and wetted again with approximately 10 times its weight of distilled water.
Page 83 - At the end of one hour the powder is squeezed in linen to free it as far as possible from the residual liquor, and washed and squeezed repeatedly with distilled water, until on adding to 50 cc.
Page 79 - ... and 100° in shallow flat-bottomed basins which shall afterwards be dried till constant at the same temperature and cooled before weighing for not less than 20 minutes in an air-tight desiccator over dry calcium chloride. "Moisture...
Page 79 - ... 1 cm. deep in a beaker placed in a good light on black glass, or black glazed paper must appear dark and free from opalescence when viewed from above. Any necessary mode of filtration may be employed, but if such filtration causes any appreciable loss, when applied to a clear solution, a correction must...

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