1550
NOTES
Vol. 56
Mrazek16the value of the quantum yield, based upon the disappearance of acetylene, must be increased to 9.7. The difference is not great enough to necessitate any revision of their conclusions. The difficulty of collecting a reasonable quantity of the photochemical polymer has prevented the determination of its empirical formula by direct analysis. The gas analysis of Kemula and Mrazek3 makes possible the computation of the MALLINCKRODT CHEMICAL LABORATORY HARVARD UNIVERSITY empirical formula of their solid product. Their RECEIVED APRIL9, 1934 MASS. CAMDRIDGE, first experiment (Table I, reference 3) leads t o the formula (C2H1.81)~and their second to (GHl.sa)n. These values are consistent with formulas The Photochemical Polymerization of Acetylene in the range (CloH9)n to (C16H1Jn. The formula CloH9 lends some support t o the BY S. C. LINDAND ROBERT LIVINGSTON following mechanism. Until recently it has been assumed that the CzHz !CY +CzH2* +CzH H (1) only product formed when acetylene is r.adiated CPH CzH2 * C4Hs (2) with ultraviolet light is a solid po1ymer.l That CIHI + CzHz-+- CsH6, etc. (3) CRH,-I CnH,-l +solid benzene is formed, under some conditio:ns, has (4) been reported by KatoJ2and has been confirmed Equation 1 represents either the dissociation of by Kemula and Mrazek3 and by Livingston and an activated molecule upon collision, or (less S ~ h i f l e t t . ~Kemula and Mrazek also detected likely) a predissociation process.’ Equation 2 traces of other aromatic hydrocarbons. In none represents the addition of an acetylene moleof these experiments is there any evidence that cule to the GH radical, which may involve a benzene can‘ be formed in chemically detectable three-body collision. The radical then adds more quantities when acetylene is irradiated at tempera- acetylene molecules, by a series of direct additures below 270’. tions, until it is removed by combination with The formation of appreciable quantities of another radical (equation 4). On the average saturated and ethylenic hydrocarbons hiss also the sum of the values of m and n is 20, which been reported by Kemula and M r a ~ e k . ~ In one corresponds to a quantum yield of 10 and to an experiment (Table I, reference 3) 17.7% of the empirical formula of CloHe. It is quite probable acetylene originally present was converted to that the product may undergo further slow re“cuprene,” and 0.64 and 0.71% to “ethylene” arrangements. The formation of benzene and and to “ethane,” respectively. In a second ex- similar compounds can be accounted for by side periment, the percentages were, respectively, 7.9, reactions, such as 0.05, and 0.27%.5 Lind and Livingston’d in CsHi +CeHe CzH (5) their determination of the quantum yield of this CeH6 €3 +CsH6 (6) reaction assumed that no condensable gases were The absence of hydrogen and the relative amounts formed, and obtained a value of 9.2. If the as- of ethylene and ethane, observed in the reaction sumption is made that the same relative amounts mixture, may be explained if it is assumed that of ethylene and ethane were formed in their ex- the addition reaction between a hydrogen atom periments as have been reported by Kemula and and acetylene is quite probable but does not ocnow than they were a year ago, probably due to gases given off by the glass, and sometimes it is difficult now to demonstrate the thin films although the mercury still sticks readily to the top of the tube. Apparently mercury adheres to clean glass much more than is ordinarily supposed, the phenomenon being difficult to demonstrate on account of the high surface tension of mercury.
+
+
+
+
+
(1) (a) Berthelot and Gaudechon, Conapt. rend.. 160, llfs9 (1910); (b) Bates and Taylor, THISJOURNAL, 49, 2438 (1927); (cl Reinike, 2. ongew. Chem., 41, 1144 (1928); (d) Lind and Livingston, THIS 64, 94 (1932). JOURNAL,
(2) Kato. Bull. Inst. Phys. Chem. Research (Tokyo), 10, 343 (1931). (3) Kemula and Mrazek, 2. physik. Chem., BZS, 358 (1933). (4) 1,ivingston and Schiflett, J . Phys. Chem.,S I , 377 (1934). (5) These percentages are based upon values of 48.4 a.nd 358.2
mm. for the final total pressures of the first and second reactions. respectively. These values were kindly furnished by Professor W. Keinnla, in a private communication.
+
cur as readily as the addition reaction between (6) This assumption while a probable one is by no means necessarily true. The pressure ranges and the wave lengths of the absorbed light were similar in the two sets of experiments, but the maximum temperature reached in the experiments of Kemula and Mrazek was 50’ higher than that in the experiments by Lind and Livingston (ptivate communication). (7) See Herzberg, Trans. Farodor Soc., 27, 378 (1931). Note, however, that light of X 1880 A. was not available under the conditions of the photochemical experiments. For a different opinion see Norrish, Trans. Faraday Sac., SO, 103 (1934).
July, 1934
NOTES
1551
that there is a limited amount of water available for reactioh. No blue color is obtained by rubbing sodium or potassium on ice. Calcium shows no colorations during its dissolution in water. Potassium gives infrequent and very small colored regions during its reaction with methyl (8) Von Wartenberg and Schultze, Z.phrsik. Chem.. BP, 1 (1929). alcohol but gives none with ethyl alcohol. LithMINNEAPOLIS, MINN. RECEIVED MAY7, 1934 ium and sodium give no such coloration with methyl alcohol. While these observations are not entirely conBlue Colored Water Solutions of the Alkali clusive it is felt that they do indicate that the Metals alkali metals form unstable blue colored solutions BY HENRYJ. WOLTHORN AND w. CONARD FERNELIUS in water. The realization that metals are physiNumerous investigators have observed that the cally soluble in water greatly conditions the point alkali and alkaline-earth metals dissolve in liquid of view which one is to adopt toward such procammonia, the alkyl. amines' and the fused alkali esses as reduction by sodium amalgam and soluamides2 to give solutions of an intense blue color. tion of metals in acids6 (5) See for example J. N. Bransted, THISJOURNAL, 63, 3626 fn. Kraus has clearly demonstrated that the solutions (1931). in ammonia contain the ordinary metal cations THEOHIOSTATE UNIVERSITY and ammoniated electrons. Franklins has long COLUMBUS, RECEIVED MAY10, 1934 OHIO thought that the alkali metals would also give similarly colored solutions in water were it not for the fact that the metals react extremely rapidly A Note on the Stereochemistry of Four Covalent with this solvent. A few years ago it was demon- Palladium, Platinum and Nickel Compounds BY F. P. DWYERAND D. P. MELLOR strated that sodium dissolves in molten sodium hydroxide (a derivative of water) to give a blue The resolution of four covalent palladium,' solution.2 More recently evidence has been ob- platinum12and nickel3 compounds into optically tained in this Laboratojr which indicates that the active antipodes, and the separation of cis-trans alkali metals are capable of forming very unstable isomers of the type [Pt XZY~], where X = "8, blue solutions in water. A brief rCsum6 of this (&H&S, and Y = C1, Br, . ., lead to the concluevidence follows. sion that either (a) planar and tetrahedral conBy confining potassium in a short length of 6 figurations of the bonds about the central metal mm. glass tubing4 so that the metal is held a t the atoms are possible in different complexes, or (b) bottom of a beaker of water and the reaction takes that the disposition of the bonds is in all cases a place in a confined space, there appear near the pyramidal one, a configuration which would acmetal at irregular intervals transient blue colored count for both types of isomerism. To establish patches of about the same intensity of color as convincing experimental evidence for (b) it must that of the alkali metals in other solvents. When be shown that a given four covalent complex conlithium is firmly packed into a piece of glass tubing taining two unsymmetrical chelate groups can exof small diameter and brought into contact with ist in cis and trans forms, the latter only of which water, a blue line a t the reacting interface is is resolvable into optical antipodes. While no frequently visible. Although sodium similarly completely satisfactory evidence along these lines confined shows no blue coloration, some such is yet available, the indications are sufficient to coloration is noticed when bits of the metal adhere warrant further search. For example, Drew and to the side of a beaker above the water level so Head4 have separated cis-trans isomers of bisiso-
ethylene and a hydrogen atom. However, this assumption does not appear to be in agreement with results of Bates and Taylorlb on the mercurysensitized reaction in the presence of hydrogen, or the results of von Waxtenberg and Schultze with Wood's hydrogenes
.
(1) For bibliography and review see C. A. Kraus, J . Franklin Insl., 212, 537--62 (1931); W. C. Johnson and W. C. Fernelius, J . Chem. Ed., 6, 20-35 (1929); W. C. Johnson and A. W. Meyer. Chem. Reuvicws, 8, 278-301 (1931). (2) For bibliography see W. C. Fernelius and F. W. Bergstrom, J . Phys. Cham., 36, 746 fn. (1931). (3) E, C. Franklin, private communication. (4) For method of filling these tubes see G. S . Bohart, J . Phys. Chem., 19, 539 fn. (1915); W. C. Fernelius and I . Schurman, J . Chem. Ed., 8, 1'765-6(19291.
butylenediamine platinous chloride; on the other hand, Reihlen and Huhn2 have obtained incomplete evidence of optical activity in the cation of (1) Rosenheim and Gerb, Z.anorg. Chem., 210, 289 (1933). (2) Reihlen and Hdhn, Ann., 489, 42 (1931). (3) Reihlen and Hiihn, i b i d . , 499, 144 (1932). (4) Drew and Head, J . Chem. SOL., 221 (1934); Nature, 132, 210 (1933).
