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COMJIUXIC.ITIOSS TO
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A NEW PYROLYTIC OLEFIN SYNTHESIS’
Sir: Xichaelis and v. Gimborn2 found that (C6Hb)aP+-CH2-C02C2H&21- decomposes slowly a t 100’ to give triphenylmethylphosphonium chloride. In a somewhat similar experiment Piaux3 reported H that C6Hb(CH3)2N+-cH2CO2C2H6I-yields phenylI trimethylammonium iodide on heating, Neither group of VA would have to make a niolecular ampli- authors reported the isolation of any other products. tude contribution of +3200° (opposite to that of I t seemed reasonable to suspect, as was suggested VIII), but the axial methyl group would lower’ by hlichaelis and v. Gimborn,2that carbon dioxide this value appreciably because of its situation in and ethylene were formed. With this in mind a series of phosphonium and a negative octant. Experimentally (Fig. 11, a ainmoniuiri salts, RsZ+-CH2C02R’X-; 2 = positive Cotton effect of +4800’ was obtained, have been which requires that another conformation play P , N ; X = Br,C1; R = C6Hb,C4H9, prepared and pyrolyzed a t temperatures ranging an important or exclusive role. If the twist In all cases an olefin, carbon formlb (of the boat VB) is written as in VC, i t will from 136-200’. be seen that two of the ring carbons (C-3 and C-5) dioxide and the appropriate onium salt were now make positive contributions,16 as does the C-5 formed. The best yields and mildest reaction methyl group, thus being in qualitative agreement conditions were found with salts, (C4Hs)3PfSeveral representative yields of with the observed curve. The driving force for CH2C02R’X olefins are: R’, cyclohexyl (57%) ; 2-octyl (76%) ; this conformational change from VA toward VC is almost certainly the relief of the buttressing 1-octyl (02%); 2-heptyl (76%); 1-decyl (67%); to which the axial C-3 hydrogen in ‘\‘A is exposed cyclohexylcarbinyl (54%) ; 1-menthyl (43%) ; don the part of the C-5 methyl function a.s well as neomcnthyl (45%) ; trans - 2 - phenylcyclohexyl one of the equidistant methyl groups of the t- (737’) ; cis-2-phenylcyclohexyl (857’) and transstilbene (90%): butyl moiety. A quantitative study of the isomer distributions obtained with R‘ = 1-butyl, 1-octyl, 2-buty1, I R = -CH(CHa)z I1 R = . . .CH(CHa)2 t-amyl revealed that both 1-butyl and 1-octyl I11 K = =C(CH3)1 give 1-butene and 1-octene of high purity (>95%) IV R = -C(CHi)s and high yield. Isomerization of the initially V R = . . .C(CHa)r formed terminal olefin can occur if i t is not reVI1 R = H IX R = -C(CHa)zCOzH moved from the reaction mixture as i t is formed. X R = . . .C(CHs)KOzH For example the 1-octyl salt gave 60% 1-octene and 40y0 isomers when the decomposition was conducted a t 170’ and the olefin was distilled a t atmospheric pressure. Under the same conditions except for reduced pressure (110 mm.) the olefin HO,’ , was > 95% 1-octene. Pyrolysis of the 2-butyl ri VI salt a t 170’ yielded a mixture of butenes: 1-butene (33%)) trans-2-butene (48%) and cis-2-butene Addition” of cyanide to (+) -pulegone (111) (19%). Decomposition of the t-amyl salt proand then hydrolysis gives two isomeric acids, ceeded smoothly a t ca. 140’ to give a mixture of m.p. 92 and m.p. 121’. Rotatory dispersion meas- methylbutenes; 2-methyl-1-butene (3270) and urements on these acids and their methyl esters 2-methyl-2-butene (G8(%). together with equilibration experiments yielded This synthetic procedure has the advantage over results very similar to those reported above, thus the more conventional ester pyrolysis in the lower demonstrating that the lower melting isomer should temperature required for olefin formation. This is be represented by I X and the higher one by X. particularly the case for the formation of terminal All of the new substances in this communication olefins from primary alcohol^.^ The drastic rewere fully characterized and gave satisfactory duction in temperatures required for effective analyses. synthesis suggests a mechanistic change from An intriguing DEPARTMENT OF CHEMISTRY CARLDJERASSI that for the usual ester p ~ r o l y s i s . ~ STANFORD UNIVERSITY E. J. WARAWA possibility involves a transition state in which STANFORD, CALIFORNIA J. M. BERDAHL hydrogen is being transferred to carbon rather E. J. EISENBRAUN than oxygen. Work on this aspect of the reaction RECEIVED JUNE 29, 1961 and its synthetic extension is being continued. A typical procedure is given: 2-octyl bromo(15) See W. S Johnson, V. J. Bauer. J. L. Margrave, h l A. Frisch, acetate, 23.0 g., 0.10 mole, and tributylphosphine, L. H. Drirger and W. N. Hubbard, J . A m . C h e m . SOC.,83, 606 (1961). 20.0 g., 0.10 mole, were mixed with cooling. The (16) Consideration of such “asymmetric“ ring forms in applications of the octant rule to stereochemical problems concerning six-membered mixture was heated to 190’ (bath) and maintained rings-similar to W. Klyne’s treatment (Bull. SOL. Chirn. France, 1396 (1960)) of cyclopentanones-will be covered in a forthcoming paper with Prof. Klyne. (17) A. Lapaorth and R . W. L. Clarke, J. Ckem. SOL, 89, 1869 (1906), isolated only one acid (m.p. 121’).
(1) (2) (3) (4)
Research supported by t h e National Science Foundation. A. Michaelis and H. V. Gimborn, B c ~ .27, , 272 (18843. L. Piaux, Compl. rend., 190, 645 (1930). C.H. DePuy and R. W . King, Chcm. Rccs., 60, 431 (1960).
COMMUNICATIONS TO THE EDITOR
Aug. 5, 1961
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a t this temperature until no more olefin distilled (3 hr.). The distillate was fractionated through a semi-micro spinning band column to give 8.3 g. (76%) of mixed octenes, b.p. 46-47’ (48 mm.). (5) National Science CoBperative Graduate Fellow, 1960-1961.
DONALD B. DENNEY SCHOOL OF CHEMISTRY vi-. CARLJ. ROSSI RUTGERS, THESTATEUNIVBSITY JOHN J. VILL~ Fig. 1.-Expansion NEWBRUNSWICK, N. J . us. d8 for solutions of sodium in RECEIVED JUNE 26, 1961 ammonia at -45’.
ON THE VOLUME EXPANSION OF SODIUM-INAMMONIA SOLUTIONS Sir :
mate that the maximum error in A V in our experiments does not exceed three per cent.; most certainly i t is less than this normally. We shall present additional data and describe our experimental method in detail in a paper to be presented soon. Support for this research from the Office of Ordnance Research, U. S. Army, is gratefully acknowledged.
We have investigated the expansion accompanying the dissolution of sodium to form dilute solutions in ammonia. The extraordinary results obtained are shown in Fig. 1, where A V is defined as, A V = (volume of solution - volume of constit- JOHN HARRISON LABORATORY OF CHEMISTRY uents)/g. atoms Na. E. CHARLES EVERS UNIVERSITY OF PENNSYLVANIA M. FILBERT 4, PENNSYLVANIAAUGUSTUS We offer a qualitative explanation for the be- PHILADELPHIA havior of AV. At infinite dilution dissociation RECEIVED JUNE 26, 1961 of metal is complete into “solvated’’ or “trapped” electrons and metal ions, and the expansion is large. As the concentration is increased, ions and electrons associate forming “atoms” and “molecules,” and A V decreases. This would suggest that the latter CONDUCTIVITY IN species may not be the highly expanded types sug- MECHANISM OF ELECTRICAL FUSED SALTS gested by Becker, Lindquist and Alder.’ The minimum in A V occurs in the concentration range Sir: where the conductance also passes through a miniWe wish to make a preliminary report on some m u m 2 This result, together with measurement recent work pertinent to the mechanism of elecof transport numbers3, indicate that incipient metal trical conductivity in fused salts. The attempts properties are commencing to show up in this re- to correlate diffusion, electrical migration and gion. I n essence, electrons are now being released fluidity data, and isotope separations by electrical to solvent, and A V increases again. migration in fused salts may all be affected by Prior to this study reliable data for A V were not these findings.’ available much below 1 X where A V is approxiMixtures of LiN03 and KN03 were placed in the mately 42 C C . ~In making estimates of the size anode compartment and pure hTahT03 in the cathof the trapped electron, i t had been assumed ode compartment of a U-shaped the compartthat this value of 4 V probably would not be too ments being separated by ultrafine Pyrex or in different from its value a t infinite d i l ~ t i o n .Judg~ some cases quartz porous plate. Electrolysis was ing by our results, the value for infinite dilution allowed to proceed and the total amount of cation appears to be approximately 41.5 cc. It is in- and the ratio of Li :K passing from anode to cathode teresting to note that the two values of AV, taken compartment were measured. The results, listed where the states of the system are vastly different, in Table I, show that within experimental error the are very nearly the same. ions move a t the same rate in all mixtures. The In our study, volume changes were measured transport number of the cation is indicative of directly using a dilatometer technique. We esti- which ion the mixture resembles most. The transport numbers of the cations in pure KNOa and (1) E.Becker. R. M. Lindquist and B. J. Alder, J . Chcm. Phys., 26, 971 (1956). LiNOs are 0.60 and 0.84, re~pectively.~
(2) C. A. Kraus, J . A m . Chem. Soc., 49,749 (1921). (3) J. L. Dye, G. E. Smith and R . F. Sankuer, ibid., 82, 4803 (1960). (4) C . A. Kraus, G. S. Carney and W. C. Johnson, ibid., 49, 2206 (1927). ( 5 ) W N Lipscomb, J. Chem. Phyr., 21, 52 (1043).
(1) G. J. Janz. C.Solomons and H. J. Gardner, Chcm. Reus., 68, 461 (1968). (2) P. R . D u k e and R . A. Fleming, J. Ekclrochem. SOC.,106, 130 (1959). (3) F. R . D u k e and B. B. Owens, ibid.. 106, 548 (1958).
