,.
For example, in the case of curve ti, Figure ti, representing a sample of milk chocolate without lecithin, we have a condition of lower viscosity a t higher stresses known as high structural viwoiity. This rheological curve bends to the left, and the relative rigidities rary greatly. I t s h o w a poor colloidal condition akin to an imperfect dispersion like mayonnaise, whose emulsion frequently breaks by simple transportation in a freightcar. The addition of 0.26 per cent of lecithin converts this milk chocolate into a perfectly dispersed colloid showing almost Sewtonian characteristics as depicted by curve 7 . Sample 3, a dark chocolate without lecithin, also displays a rheological curve which bends to the left, and has varying rigidities. This is probably due to its rinusual fineness or special heat treatment in processing.
I
,
ANALYTICAL EDITION
lune 15, 1941
400
1
600
800
120C
IOOC
I400
7
405
(15) Schwarz. R., and Hubbard, W., Cocoa and Chocolate, 2, No. 0, 14 (1936). “Industrial Rheology”, p. 22, Philadelphia, (16) Scott Blair, G. W., P. Blakiston’s Son & Co., 1938. (17) Segel, F., P h y s i k . Z.,4, 493 (1903). (18) Stanley, J., Confectionery Production (London), 5 , No. 8, 22 (1939). (19) Waele, 9.de, i n “Wetting and Detergency” (symposium), p. 57, New York, Chemical Publishing Co., 1937. (20) Working, E. B., U. S.Patent 1,781,672 (Nov. 11, 1930). (21) Zenlea, B., Cocoa and Chocolate, 1, No. 6, 14 (1935). PRESENTED before the S5th Annual Meeting of the hssociation of Official Agricultural Chemists, Washington, D. C.
Continuous Water Remover JACK H. THELIN Rutgers University, New Brunswick,
N. J.
I
1
‘Ut
5t
0
150 150
650 200
250
30C
350
K THE preparation of isoamyl ether from isoamyl alcohol by the use of concentrated sulfuric acid, it was deemed advisable to effect a continuous dehydration of the reaction mixture. Inquiries were made among other chemists with the disclosure that none was familiar with a water remover as simple in operation as the one described here. No particular claim for originality is made, but to the author’8 knowledge this particular modification is new.
7
STRESS MACM DEFLECTlOhr
FIGURE6. RHEOGRAM O F MILK CHOCOL.4TE With (7) and without (6) lecithin showing high structural viscosity in absence bf lecithin
Table XV shows that the liquor liaa practically tile same body BS the buttermilk, despite the great difference in viscosity between these two samples. The body is as important a factor as the viscosity when considering the covering power of the chocolate. Indeed, we know from actual experience that despite its lower viscosity the liquor will show a covering power comparable to buttermilk chocolate of much higher viscosity.
’if
Literature Cited Anon., Confectionery Production (London), 5 , No. S, 11 (1939). Barr, G., “.Monograph of Viscometry”, p. 222, London, Oxford University Press, 1931. Bingham, E. C., “Fluidity and Plasticity”, pp. 216, 323, Nem York, McGraw-Hill Publishing Co., 1922. Bingham, E. C., and Green, H., Proc. Am. SOC. Testing 41aterials, 19, 11, 649 (1919). Freundlich, L., Food Industries, 9, No. 11, 630 (1937). Ibid., 11, No. 11, 612 (1939). Fuller, E. C., and Johnston, W. A , , “Applied Mechanics”, Vol. 11, Strength of Materials, p. 375, New York, John Wiley & Sons, 1918. Green, H., Proc. Am. SOC.Testing Muterials, 20, 11,451 (1920). Langwill, K. E., and Langwill, J. V., Cocoa and Chocolate, 2, No. 5, 20 (1936). Mac.Michae1, R. F., J. IND.ESG.CHEM.,7, No. 11, 961 (1915). Margules, M . , Sitzber. A k a d . W i s s . mien, A b t . I I a , 83, 588 (1881). Mooney, M.,in “Symposium on Consistency”, p. 9, Philadelphia, Am. Soc. Testing Materials, 1937. Perrott, G., and Thiessen, R., J. IXD.ENG.CHEhf., 12, 325 (1920). Pochettino, A , , Nuoeo cimento, Series 6 , 8 . 77 (1914).
The apparatus is simple and easy to construct, requires 110 attention during operation, and may be used in many other reactions besides distillations involving the removal of water. T h e side arm, A , was filled t o about point C with water at the start of the refluxing. T h e returning reflux liquids became entrapped in A and t h e water portion sank t o t h e bottom. The excess alcohol overflowed back into t h e reaction flask. The water, on accumulation in A , overflowed from opening D and dripped off t h e side arm at E. A t B the side arm was made of two sections connected b y a short length of rubber tubing. This made i t possible t o lengthen or shorten the overflow tube with a consequent raising or lowering of t h e alcohol-water interface at C. In this way only a small quantity of alcohol was entrained at C a t a n y time.
