V O L U M E 2 0 , NO. 1, J A N U A R Y 1 9 4 8
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Cereal Laboratory Methods with Reference Tables. American dssociation of Cereal Chemists, University F a r m , St. Paul 1, Minn., 1947. Fifth edition. xiv 341 pages. Price, $4.50.
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T h e fifth edition of “Cereal Laboratory Methods,” published by the American Association of Cereal Chemists, has been revised and expanded b y the association committee, F. C. Hildebrand, chairman. T h e amount of expansion is indicated by the increase from 264 to 341 pages and the addition of 3 new chapters. T h e new chapters are on experimental malting, vitamin assay methods, and sanitation methods. T h e first contains directions for steeping, germination, and kilning. T h e second includes methods for determining vitamin A, carotene, thiamine, riboflavin, nicotinic acid, pantothenic acid, vitamin B6 complex, and choline; in the previous edition only the thiamine method was described in detail. T h e third new chapter on sanitation methods has nine sections dealing with detection and/or determination of foreign matter in
flour, rodent contamination, bacteria and molds, and residues from plant fumigations. ;It numerous points elsewhere in the hook the methods have been modernized, b u t essentially the same topics are covered again in the other fourteen chapters. The most important change in the appendix is the elimination of tables and charts for conversion of weights and analytical values to 13.5 and 15.0% moisture levels; these are replaced by a single table for converting all analytical T-alues (except ahsorption) to 14.0% moisture, which has become a standard practice in cereal laboratories. Another new table gives correction of ahsorption values to 14.0% moisture basis. Revision has enhanced the usefulness of the book. I t is indispensable in laboratories concerned with cereal foods and feeds. Paper, printinq. and binding are first class. R. C . SHERWOOD
oxide is oxidized to nitrogen peroside hy rhe nitric acid and the oxidation advances autocatalytically to an explosion. The reaction between nitric and nitrous acids is accelerated in the presence of traces of heavy metals and Hofmann ( 3 ) states: “Stable SIR: salts of cobalt (111)are all of a complex nature and are formed from Paiva S e t t o and Catani ( 5 ) explain the explosion of cobaltinitrite the corresponding cobalt (11)salts by oxidation by air, some of them a s reported by Broughton and associates ( 1 ) as due to the formation by dissociation of water or reduction of solvent.” Broughton and of fulminic acid, and state t h a t another explosive compound formed is associates ( 1 ) say: “Presumably, the only constituents in the filtrate ethylnitrolic acid. Available literature sources show t h a t both these were sodium acetate, acetic acid, sodium nitrite, sodium nitrate, and compounds will be formed, b u t make no mention of the reason for the a trace of cobalt.” This combination of nitric acid, nitrous acid, and explosion or how to avoid the danger. organic solvent shows us a practically ideal setup for an explosion, JTieland (8) has stated the following chain as leading to the formavhereas no explosion occurs in the absence of nitric acid plus cobalt. tion of fulminic acid: S o mention was made in conHSOz HSO3 HxOa nection with t h e Tesas City CHaCHO +HC.CHO ---+ HC.COOH ---+ OnS.C.COOH +OzS.CH (+COI) +C ( + H S O r ) (]isaster of traces of llitrite in I 11 I I I the ammonium nitrate i n the S.OH N.OH X.OH N.OH T.OH presence of organics (was coating. paper bags, etc.) The chain leading to t h e simplest of the nitrolic acids starts from
Explosion of Cobaltinitrite
H nitromethane, CH&O? or
\ C H . S O ? , which in its aci form,
H’ H
\C=S=O,
reacts with Hh’Oi-
I
H ’
r
H?C-S=O
1
[NO
OH form HC--NO1,
i\
OH
’
1
4 to
OH]
methylnitrolic acid, water ( 7 ) .
11
NOH The salts of the nitrolic acids are explosive themselves and change easily into fulminates. The formation of the nitroparaffin t h a t starts this chain is easily explained by the old method of nitromethane preparation HSOi C H K l C O O H +CHx(SO2)COOH +CHaSOz (+ CO2) Unpublished work in a Viennese laboratory (6) has shown t h a t under certain conditions this chain can be started from acetic acid (nonsubstituted), though the yield is small. Kef ( 4 ) has demonstrated t h a t t h e mercuri salt of nitromethane can be changed in one step into mercuri fulminate. ( C H F N O , 0 ) 2 H g = (C=SO)zHg
+ 2Hz)
We have therefore a t least two chains leading to the fulminate. Both chains require the presence a t the same time of nitrate and nitrite, and this extremely dangerous mixture of nitrate, nitrite, and organic material will lead to the formation of explosive compounds if t h e worker does not take the utmost care. Gattermann (8)describing the preparation of ethyl nitrate warns t h a t ethyl alcohol will not be oxidized by pure nitric acid b u t only esterified. I n t h e presence of traces of nitrous acid oxidation ensues with the formation of nitric oxide. Nitric
LITERATURE CITED
Broughton, D. B., Laing, >I. E., and TJ-entwortli. R.L., .Is.AL. CHEM.,19, 72 (1947). Gattermann, L., “Die Praxis des organischen Cheniikers.” p . 141, Berlin, W. de Gruyter 8: Co., 1930. Hofmann, K. A,, “Lehrbuch der anorganischen Chemie.” p. 636, Brunswick, Fried. Vieweg und Sohn, 192s. Kef, J. C., Ann., 280, 273 (1894). Paiva Netto, J. E. de, and Catani, R. .I.,.%SAL. CHEM..19, 818 (1947). Pavelka, E., and associates. unpublished data. Sidgwick, N. V., “Organic Chemistry of Kitrogen,” p. 241 (methylnitrolic). p. 230 (CHISOL),Oxford, Clsrendon Press, 1937. Wieland, H., Ber., 43. 3382-4 (1910). OSKARHOROWITZ 235 Leffei ts Ave. Brooklyn 2 5 , N. T.
Cartesian Diver Type of Manostat-Correction I n t h e article entitled “ T h e o r y a n d Operation of a Cartesian D i v e r T y p e h l a n o s t a t ” [IHD.ENG.CHEM.,ANAL.ED., 18, 633 (1946)] t h e s t a t e m e n t should b e a d d e d u n d e r “Equilibrium of B u o y a n t Forces” (immediately following E q u a t i o n 3) t h a t the a r e a of t h e inner t u b e has been neglected. If this a r e a is n o t neglected, E q u a t i o n 8 m a y b e w r i t t e n as:
where A0 = cross-sectional a r e a of inner v e n t t u b e and VO = ROGERGILMONT volume of gas inside float.
