| Autor: |
Werkman, C. H., Osburn, O. L. |
| Zdroj: |
Experimental Biology and Medicine; December 1930, Vol. 28 Issue: 3 p241-242, 2p |
| Abstrakt: |
An accurate and rapid method for the quantitative determination of alcohols in fermentation mixtures would prove of value to the zymologist engaged in studies of the chemism of microbial action. A method which has been found very satisfactory is based upon the oxidation of the alcohols in the neutral volatile distillate by potassium dichromate and phosphoric acid. Ethyl alcohol yields acetic acid and butyl alcohol yields a mixture of butyric and acetic. The acids are quantitatively determined by the partition method.1The method is presented in its present form for the quantitative determination of unknown mixtures of butyl and ethyl alcohols, such as are found in the “butyl-acetone” fermentation. This fermentation has extensive industrial use in the production of butyl alcohol and acetone.Fifty cc. of the alcohol mixture are pipetted into a 200 cc. balloon flask containing 10 gm. of potassium dichromate and 25 cc. of c.p. 85% phosphoric acid. Three or 4 small pieces of porcelain are added to insure smooth boiling and the flask is connected to an efficient reflux condenser. The flask is then heated at such a rate that the mixture is brought to a boil in one and one-half minutes. Gentle boiling is maintained for 3 minutes, making the total time of heating between 4 and 5 minutes. It is advisable to wash down the condenser tube occasionally by adding 5 cc. of water at the top. The volume of liquid in the flask should never exceed 100 cc.After oxidation is complete the flask is quickly connected to a Liebig condenser and distilled until the mixture in the flask begins to foam. The heat is then lowered until foaming just continues. The heating is then continued for 2 or 3 minutes. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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