Mass spectra of deuteroacetylenes, monodeuterobenzene, and deuteronaphthalenes

Abstract

and naphthalene it is possible to measure the isotopic purity at ionizing voltages below the appearance potential of any fragment ion s and to correct the observed spectra of monodeutero compounds for isotopic impurity.For C,HD the probability of removing the H atom is nearly twice as great as that of removing the D atom. In monodeutero benzene and naphthalene, on the other hand, there is no .such se lectivity, and it is possible to compute the spcctra of the monodeutero compounds on the basis of equal a priori probability of removing a single H or D atom. By assuming that equal probab ili ty holds for doubly charged ions, the complete doubly charged ion spectra can be computed from t he observed half-integer pcaks. Similarly, t he spectra of ClODs and ClOHD7 are computed from a spectrum of a mixture of the two compounds.

La formation de biphénylènes par pyrolyse de mélanges de précurseurs de benzynes

“…Dans la pyrolyse de l'anhydride phtalique, le chromatogramrne montre la presence de trois produits dont deux d'entre eux sont I'anhydride phtalique et le naphtalene; ils ont Ct C identifies par leur spectre de masse (24,25) …”

Redetermination of mass spectra of deuteromethanes

“…Schissler, Thompson, and Turkevich [2] report a value of 1.09 for monodeuteroethane. In monodeuterobenzene and monodeuteronaphthalene it, was found that the factor is nearly unity [7]. There is no obvious explanation for weighting factors that differ much from unity as is the case for the deuteromcthanes .…”

H-D isotope effects in the decomposition of acetylene by electron impact

“…It is not difficult to show that processes which are not taken into account in figure I are probably only of minor importance, with the possible exception of the reaction C2H+~C~+H +. The reaction scheme has been simplified by omitting this reaction, since isotopic changes in the relative abundance of H + and D + have not been determined for acetylene [7], and the data in figure 1 and in Appendix 1 show that reaction (4) is at least partly responsible for H + ions. It is concluded in w 5 that formation of H + from C2H + does not have a marked effect on isotopic changes that have been observed.…”

“…Reaction (8) is a more simple process, but the relative abundance of C2Ho. ++ and C2D~++ has not been directly determined by Mohler et al [7] and was taken as equal to that of C2HD ++.…”

“…Decomposition of acetylene by electron impact is considered, since this molecule has only four atoms, and the mass spectra of the isotopic molecules C2H2, C2HD and C2D2 have been determined [7]. The quasi-equilibrium theory is used to obtain an approximate description of the reaction kinetics, which is modified to yield exact agreement between the calculated and observed mass spectrum of C2H2.…”