THE ANALYST. I1 NOTE ON REfGHERT'S DX8TXLLATION PROCESS, BY ALE'RED H. ALLEN. Read at the Meeting, Decernbe?. 8th, 1886. IN a paper read before this Society in the spring of last year, and published in the ANALYST for June, 1885, I described my experience of Reichert's method of assaying butter-fat, and gave a number of figures illustrating the results obtained with oils of various kinds. These figures professed to represent the volatile acids in terms of butyric acid, and were obtained by multiplying the numbsr of centimetres of decinormal alkali required for neutralising the distillate from 2.5 grammes of fat by the factor 0,312. I am indebted to Mr. W. F. K. Stock for pointing out an error in this factor, which should be 0.352." As the erroneous factor was used in calculating the figures already referred to, it follows that they are all too low in the proportion of 312 : 352, or 39 : 44.A further experience in the employment of Reichert's process for examining fats h a s led me to abandon the expression of the results in terms of butyric acid, in fa,vour of a atatcment of the weight of caustic potash neutralised by the distillate from 100 grammes N *0088 x 100- 10 2.5 * 1 c,c, of - alkali neutralises 0.0088 gramme of butyric acid, and -- - 352. The erroneous €aetor may have resulted from the fraotion-- -0078 x 100- - -812.19 THE ANALYST. of the oil. by the distillate from 2.5 grammes by the factor 0.2244.* This is obtainable by multiplTing the volume of decinormal alkali neutralised The following table contains a number of results expressed in both ways :- Fatty Oil.Butter or Milk-fat; COW’S . . 9 7 ,, Ewe’s . . 9 9 ,, Goat’s . . Y ? ,, Porpoise’s Cocoanut oil . . . . . . Palmnut oil . . . . .. Palm oil . . .. . . Cacao butter . . .. . . Butterine and oleomargarine . . Whale oil . . . . . . .. J 9 Porpoise oil . . Sperm oil . . Bottl.enose oil . . Menhaden oil . . Codliver oil . . Sesame oil . . Cottonseed oil . . Castor oil . . .. . . . . .. .. . . .. . . . . . . . . . . .. * . 0 . . . . . . . N 10 3.C. of - alkal -equired by 2.5 gi 12.5 to 15.2 13.7 13.6 11.3 3.5 to 3 7 2.4 0.8 1.6 0-2 to 1.G 3.7 12.5 11 to 12 1-3 1.4 1-2 1.1 to 21.1 2 *2 0.3 1.4 KHO required b 100 parts of oil. 2.80 to 3-41 3.07 3.05 3.51 0.78 to 0.83 0,64 0.18 0.36 0.04 to 0 ~ 3 6 2.80 2.47 to 2.69 0.29 0.31 0.27 0 24 to 0.47 0.07 0-31 o m 0.48 Observer.Reichert, Caldwell, Moore, Allen, etc. Schmitt Allen Reichert, Moore, Allen Allen Moore Caldwell, Moore, Allen Allen I , ) ? 9 , 9 9 11 9 , Y, Y, 9 , Moore Allen From these results, it is evident that the fats of different kinds of milk (butter-fats) are sharply distinguished from nearly all other fats by the large proportion of soluble volatile fatty acids they yield by Ileichert’s process. The most remarkable exception is presented by porpoise oil and some samples of whale oil. I n porpoise oil I have found 5 per cent of valeric acid, and Chevreulobtained as much as 9.63 per cent. I n a recent paper I pointed out that in porpoise-butter the glyceride of valeric acid appeared to replace the butyrin characteristic Qf the butter of terrestrial mammals.Some of the chemists who have employed Reichert’s process take the precaution to filter the distillate before titrating it, so as to get rid of any volatile acids which may be insoluble or very sparingly soluble in water. This plan may sometimes be adopted with great advantage. Thus when the solution of the soap obtained by saponifying cocoanut or palmnut oil is acidulated and distilled, a notable proportion of lauric acid passes over and solidifies in the condenser or on the surface of the distillate; and by adding water to the contents of the retort, again distilling, and repeating this process several times, a very considerable proportion of volatile fatty acids can be obtained from cocoanut oil. I n assaying butter the appearance of insoluble acids in the distillate would *00561 x 100 = .2244, * 1 C.C.of & alkali contains 0.00561 gramme cf KHO ; and 2.5THE ANALYST. 13 furnish a valuable indication of the presence of cocoanut oil, and they should be removed by filtration j or the distillate will be found t o neutralise so‘ large a volume of alkzli as considerably to diminish the practical value of the process as a means of dist,inguishing butter from butter-substitutes, as has been pointed out by Moore and others. Latterly, I have adopted the plan of filtering the distillate in all cases, washing the filter with cold water, and then immersing the filter, with any adhering insoluble acids, in alcohol, which is then titrated with decinormal alkali and phenolphthalgin.I n the case of ordinary butters and butter-substitutes the insoluble woolatile acids only neutralise about 0.2 C.C. of decinormal alkali. The question having recently been raised, the following experiments were made at my request by Mr. William Barraclough on a sample of butter-fat, in order to ascertain the variation in the results of Reichert’s process produced by modifications in the methods of conducting the saponification and distillation. 1. 2.5 C.C. of butter-fat was saponified by alcoholic potash in an open basin, the alcohol evaporated off completely at a steam heat, the residual soap dissolved in water, the solution acidulated with sulphuric acid in slight excess, diluted to 75 c.c., and dis- tilled gently in a globular flask with side-tubulure adapted to a condenser, until 50 C.C.had passed over. The flask held 460 C.C. up to the side-tubs, and some fragments of pumice-stone coiled round with platinum wire were added to the contents, to promote evolution of vapour. 2. An exact repetition of No. 1 experiment. 3. Saponification was effected in a flask furnished with a long tube and heated by 4. Saponification was effected in a well-closed bottle placed in the water-oven. Other 5. Manipulation exactly as in experiment 3, except thnt the distillation was con- 6. Conducted as in experiment 3, except that the distillation was conducted in a 7. Blank experiment with the alcoholic potash employed in the previous experi- The alcoholic potash was steam. manipulations unchanged. ducted in a flask fitted to the oondenser by a cork and bent tube. retort. ments, the manipulation being like that in experiment 3. brown and not very recently prepared. The subsequent manipulations were the same as in experiment 1. Experiments. Decinormal Alkali Decinormal Alkali for 2.6 grammes. for 2.5 grammes. No. 1 L . . . 11.80 C.C. No. 5 . . . . 12.40 C.C. No. 3 .. . . 12.40 ,, No. 7 . . .. 0.25 ,, No. 4 . . . . 12.50 ,, These results show that a sensible loss occurs if the saponification be conducted in On the other hand, This No. 2 . . , . 11.85 ,, No. 6 . . * . 12.45 ,, an open basin, doubtless owing to the formation of butyric ether. the exaot nature of the distilling apparatus appears to be of little importance. latter conclusion is not in accordance with the experience of some other chemist& Conclusion of the Society’s Pmceedings,