Hill, A. G., Hill, A . J. (to Calco Chemical Co.), U.S. Patent 2,098,039 (Kov. 2, 1937); CA 32, 192h (1938). Hill, A. G., Hill: A. .J., I n d . Eng. Chem. 43, 1583 (1951). Hill, A. G., Shipp, J . H., Hill, A. ,J., I n d . Eng. Chem. 43, 1579 (1951). Hirschler, A. E., J . Catal3,sis 2, 428 (1963). Hougen, 0. A., I n d . Eng. Chem. 53, 509 (1961). Hougen, 0. A., b'atson, K . WI., "Chemical Process Principles," Part 111, p. 961, Wiley, New York, 1947. I. G . Farbenindustrie, A,-G., French Patent 843,843 (July 11, 1939); Chem. Zentr. 1939, 11, 3345. Inoue, H., Bull. Chem. SOC.Japan 1 , 167 (1926). Kikvidze, A,, Tr. I n s t . Khim., Akad. S a u h Gruz S S R 14, 161 (1958). Kikvidze, A., Areshidze, Kh., J . Gen. Chem. ICSSR) 23, 619 (1953). Kirk, K., Othmer, D., "Encyclopedia of Chemical Technology," Vol. I, p. 924, Interscience, New York, 1947. Kozlov, N., Gudz, N. V., Pasternak, V., Zh. Prikl. Khim. 37 ( l o ) , 2326 (1964); CA 62, 463d (1965). Liengme, B. V., Hall, W. K., Trans. Faraday Soc. 62, 3229 (1966). Mailhe, A , , de Godon, F., Compt. Rend. 166, 467 (1918). Maxted, E., Brit. Patent 577,901 (June 5, 1946); CA 41, 2080' (1947). O'Donnell, J. F., Mann, C. K., Anal. Chem. 36. 2097 (1964). Parera, J. M., Duarte, R., Rev. Fac. Ing. Quim. 34/33, 85 (1966). Pines, H., Haag, W. O., J . A m . Chem. Soc. 82, 2471 (1960). Roure Bertrand Fils et Justin Dupont, S.A., French Patent 51,201 (Dec. 20, 1941). Shuikin, N. I., Bitkova, A. S . , Ermilina, A. F., J . Gen. Chem. ( I ' S S R ) 6 , 744 (1936); CA 30, 6346" (1936). Smolensky, E., Smolensky, K., Roczniki Chem. 1 , 232 (1921). Tamele, M. W., Discussions Faraday Soc. 8, 270 (1950). Thomas, C. L., I n d . Eng. Chem. 41, 2564 (1949). Weisz, P. B., Prater, C. D., AdGan. Catalysis 6, 143 (1954).
The difference between the selectivities of alumina and silica-alumina (natural or synthetic) is caused by the different nature -of their acid sites. On the dehydrating acid sites of silica-alumina MA adsorbs irreversibly, blocking them for alcohol dehydration. This bondage is so strong that MA is not displaced, even though methanol alone is passed for several hours. Instead, on the acid centers of alumina both reactants are adsorbed, and methylation and dehydration occur. MA is weakly adsorbed, and if it is eliminated from the feed, it desorbs, returning the alumina to its initial dehydrating activity. The silica-aluminas pretreated with MA and the less active alumina were methylating agents of MA, but did not catalyze the formation of ether when pure methanol was fed. This means that methanol methylates directly, and that formation of dimethyl ether is not a necessary prerequisite for methylation of the amine. As the equilibrium conversion for dehydration of methanol is large, no formation of ether is due to a kinetic limitation. This fact has no influence on the methylating action of methanol. This conclusion differs from those of other authors (Fuortes and Montagnani, 1951). Chromatographic analysis showed that in all cases the methylation was select,ive; the nitrogen, and not the ring, was methylated. Stability. All the active catalysts are very stable, and all were regenerable by burning the carbonaceous deposit in air. Literature Cited
Brown, A. B., Reid, E. E., J . A m . Chem. Soc. 46, 1836 (1924). Earl, J. C., Hills, N. G., J . Chem. SOC.1947, 973. FIAT, Rev. Ger. Sci., Final Rept. 1313, 1, 418 (1946). Fuortes, C., Montagnani, S., A n n . Chim. (Rome) 41, 515 (1951). Gibian, C., Kaufler, F., Spence, G., Australian Patent 116,049 (March 21, 1946); CA 41,992'(1947). Groggins, P. H., "Unit Processes in Organic Synthesis," p. 850, McGraw-Hill, New York, 1958.
RECEIVED
for review January 9, 1968 ACCEPTED April 22, 1968
COMPATIBILITY OF INORGANIC AZIDES WITH ORGANIC EXPLOSIVES J E R O M E
M.
ROSEN
A N D
H E R B E R T
T .
SIMMONS,
S R .
U . S. Naval Ordnance Laboratory, White Oak, Silver Spring, M d . 20910
ATT,EMPTS have been made to
develop detonators containing lead azide in contact with various high-melting explosives for use a t temperatures in the range of 200" to 260°C. Lead azide was found to react a t these high temperatures with explosives such as cyclotetramethylenetetranitramine ( H M X ) and 1,3-diamino-2,4,6-trinitrobenzene (DATB). We decided to investigate, in a general way, the problem of azide-explosive interaction because of the continuing interest in heat-resistant detonators for both military and aerospace applications (Pollard and Watson, 1967). 262
l & E C PRODUCT RESEARCH A N D DEVELOPMENT
Results and Discussion
Trinitrobenzene (TNB) was selected as a model explosive compound in this study of azide-explosive interaction, as T N B does not undergo any significant thermal decomposition, even at 300°C. (Rosen and Dacons, 1968). Vacuum thermal stability measurements a t 260" C. showed a strong T X B interaction with cu-lead azide as well as sodium azide (Table I ) . All of the materials used were carefully purified. The lead azide did not contain any organic additive.
Azide-explosive interaction at elevated temperatures was investigated using trinitrobenzene as a model high explosive. Both lead and sodium azide reacted with trinitrobenzene at 26OoC.,
CIS
evidenced by the large volume of gas evolved
and the formation of a black insoluble product which did not melt at 475'C. The reaction was interpreted as an oxidation of the azide ion by the nitro groups, and must be considered as a limitation on the use of azides in intimate contact with typical organic explosives at elevated temperatures. Another example of explosive-azide interaction is shown by cyclotrimethylenetrinitramine in contact with commercial lead azides at 165' C.
Table I. Vacuum Stability Dmto at 260' C.
(Gas at NTP produced during 1st hour, CC.per gram) TNB
aPb(N:,), TNB,
NaN:, Pb(N:,), (Control) (Contml) (Control)
NaN.IITNR, 2.5f1
1/10
60/g. azide
4118. azide
