REACTIONS O F T H E TYPE Clz
+
2
KOH
KC1
=
+ KClO + HzO’
BY F. W. BERGSTROM’
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Downloaded by UNIV OF CALIFORNIA SAN DIEGO on September 1, 2015 | http://pubs.acs.org Publication Date: January 1, 1925 | doi: 10.1021/j150259a002
Introduction and Discussion Potassium amide3 reacts readily with strongly electropositive elements such as sodium, lithium, and calcium, more slowly with magnesium, aluminum and lanthanum, and very slowly with cerium, zinc and manganese4. Elements between cadmium and cobalt in the electropotential series fail to react with solutions of potassium amide. A solution of this base was found to react very slowly with lead and bismuth, more readily with tin, antimony, arsenic, and tellurium, and very readily with selenium, sulfur, and iodine. Potassium amide thus reacts most readily with strongly electropositive or strongly electronegative elements, while the rate of reaction approaches zero in the case of elements of intermediate electroaffinity, such as cadmium, iron, and cobalt. The reactions with these classes of elements were found to differ in type. Strongly electropositive elements react initially with basic amides with the formation of solutions of the more electropositive metal: ( I ) A1 3 NaNHz A1(NHz)3 3 Na.5 Subsequent reactions of sodium upon the solvent and of sodium amide on the amphoteric base, aluminum amide, lead to the formation of sodium ammono-aluminate, A1(NH2)2NHNa.NH3: The initial reaction of an electronegative element with potassium amide is similar to that of chlorine with a cold dilute solution of potassium hydroxide in water: ( 2 ) Clz 2 KOH = KC1 KClO HzO. Some other reactions of this type6 that have been recognized in aqueous solution are the following :
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‘The Action of Solutions of Ammono Bases in Liquid Ammonia on Elements more Electronegative than Nickel. I. National Research Fellow. aPotassium amide is a base in ammonia, just as potassium hydroxide is 9, base in water. Franklin: J. Am. Chem. SOC.46, 2139 (1924). 4 Franklin: J. Am. Chem. S O C 35, . 1463 (1913); J. Phys. Chem. 23, 41 (1919); J. Am. Chem.. Soc. 37,2300 (1915); Fitzgerald; 29,660 (1907);Bergstrom, 45, 2788 (1923);46, 1548, 1552. (1924); 47, 1836 (1925). I n general terms, Mn $. n A N H 2 FM(iYH2)n nA, where M is a metal, such as aluminum, of positive valence, n, and A is an alkali metal. See Kraus and Kurtz: J. Am. Chem. Soc., 47, 45 (1925); Bergstrom: 45, 2788 (1923); 47, 1836 (192 j) hIellor : “ A Comprehensive Treatise on Theoretical and Inorganic Chemistry,” vol. 2, p.50 (i922); Tartar and Draves: iJ. Am. Chem. Soc. 46, 574(1924)1. Arsenic, phosphorus, and siiicon react with alkali hydroxides t o give as one of the reaction products, respectively, arsine, phosphine, and hydrogen. Wint8er[J. Am. Chem. SOC.,26,1329 (1904)]correctly considersthat sodium phosphide is one of the primary products of the action of sodium hydroxide on phosphorus. Sodium phosphide is readily converted by hydrolysis to phosphine and sodium hydroxide. Undoubtedly, sodium arsenide is one of the primary products of the reactbn of sodium hydroxide upon arsenic. Arsine is, of course, readily formed by hydrolysis of sodium arsenide.
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REACTIONS O F THE TYPE C12+2KOH
Downloaded by UNIV OF CALIFORNIA SAN DIEGO on September 1, 2015 | http://pubs.acs.org Publication Date: January 1, 1925 | doi: 10.1021/j150259a002
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I3
2 KOH = z K F HzO I/Z 0 2 (3) Fz Iodine and bromine react initially as in ( 2 ) (4) 2)s 6 KOH = z KzS, KzSz03 3 HzO. ( 5 ) (ZX (zx 1)Se 6 KOH = z KZSe, KzSe03 3Hz0. (6) 1)Te 6 KOH = z KzTe, K2Te03 3 HzO. (7) (zx It is the purpose of the present investigation to examine in detail reactions of this type occurring in liquid ammonia as solvent. It was found that elements more electronegative than nickel react with solutions of potassium amide, and, to a less extent, with solutions of other ammono bases, provided that the alkali metal salts of that element are soluble in ammonia.’) Na S H 3 --t H Z NaNHz, a reaction catalyzed by AI and A1(NHd3; NaKHZ Al(NHz13 --t AI(NH2)NHNa.NH3. Tin reacts with sodium or potassium hydroxide to form a stannite and hydrogen, while phosphorus reacts with this base to form a hypophosphite and phosphine. I n view of the fact that potassium amide reacts with these elements in ammonia initially according t o the type reaction illustrated by equation ( z ) , it is probable that the reactions of these elements and arsenic with bases in water all take place in an analogous manner. Due to hydrolysis, the alkali stannides formed by the action of sodium or potassium hydroxide on tin are converted to stannane, SnH4,which is unstable and decomposes to give tin and hydrogen.a No satidfactory mechanism has heretofore been proposed for the action of aqueous solutions of bases upon tin.4
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The Reaction between Potassium Amide and Iodine Iodine reacts very rapidly with potassium amide at -33’ with the formation of potassium iodide and nitrogen, according to the equation (8) 6 I 6 KNHz= 6 K I 4 NH3 Nz. Obviously, this reaction is analogous to the action of fluorine on a solution of potassium hydroxide.(g). Calculated from (8), 29.4 cc. of nitrogen (standard conditions) would be liberated by the action of potassium amide upon one gram of iodine. Experimentally there was collected 38.6 and 37.8 cc. nitrogen (reduced to standard conditions) when 1.160and 1.118g. iodine reacted with an excess of potassium amide. This corresponds respectively to 33.3 and 33.9 cc. nitrogen per gram of iodine. The apparatus used for collection of gas was not altogether satisfactory. Iodine was melted into glass tubes of 5 mm. diameter, convenient lengths of
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1 Potassium and sodium form soluble salts of homo-atomic anions containing lead, tin, bismuth, antimony, arsenic, phosphorus, tellurium. selenium. sulfur, iodine. Kraus; J. Am. Chem. Soc. 44, 1220 (1922). E.g, KaPbs, Na3Sb,, NazTe4, KzSes, I
