General Scope

In the first half of the twentieth century, positive-ion molecule reactions and the interaction of hyperthermal electrons with molecules were emphasized. Some thermal electron molecule reactions in flames and electron swarms were investigated [3]. Prior to 1950 only the electron affinities of hydrogen and the halogen atoms had been measured. A 1953 review on electron affinities noted 

The determination of further electron affinities is not an easy matter it is possible that the electronic equilibrium method could be extended to a few more elements, but at the temperatures involved, molecules and radicals would be decomposed. The only reasonable hope of estimating the electron affinities of radicals would seem to lie in a study of the appearance potential of negative ions, and the determination of their kinetic energies, although it must be borne in mind that a careful search of the mass spectrum of methane has failed to reveal the existence of a CH3(-)ion. [4] 

In the late 1960s several major advances were made in the study of thermal electron reactions. These were based on the ECD, the extension of the magnetron method of studying electron molecule reactions to determine equilibrium constants for electron molecule reactions, and the invention of high-pressure thermal electron negative-ion sources for mass spectrometry [5-7], Electron swarms were also used to determine rate constants for thermal electron reactions [8, 9]. The electron affinities of molecules were measured using electron and alkali metal beams [10, 11]. Relative electron affinities were obtained from the direction of the reaction of a negative ion with a molecule [12, 13], Other major advances were photodetachment and photoelectron spectroscopy [14—17], 

This book is based on the study of reactions of thermal electrons with molecules using the ECD, negative ion chemical ionization (NICI) mass spectrometry in the gas phase and polarographic reduction in aprotic solvents [18]. Only the complementary studies related to our research are considered here. 

Until recently, there were few theoretical methods available to test experimental results. With the developments in computer software and hardware, it is now easy 

---

The subject matter of this chapter is arranged largely on the basis of reaction type rather than on specific functionality to be introduced. This arrangement allows a balanced presentation of the various methods and avoids repetition. Reference to the general scope of a given reaction is provided in the text when alternate methods are available for the preparation of a particular system. 

Rearrangement of acetylenic sulphenates to the allenic sulphoxides 151 was discovered when the synthesis of propargylic ester of trichloromethanesulphenic acid 152 was attempted (equation 86). This reaction is of general scope and gives very good yields of allenic sulphoxides (Table 14) from structurally diverse cohols and various sulphenyl chlorides Reaction of alkynols 153 with benzenesulphenyl chloride in the presence... 

This facile and versatile conversion of cyclopropenones to 2-pyrones is prepara-tively satisfying (yields are generally up to 80%) and proves to be of general scope ... 

A comprehensive chemistry of ferrocene and other metallocenes has been developed. The introduction presented here is meant to acquaint the reader with the general scope and nature of the field, and more details will be found in the references at the end of this chapter. 

First, to the extent that TSCA and the Sixth Amendment do not have the same general scope and coverage, this necessarily will mean that companies in some cases will face regulation of their (new) chemicals and commercial activities in one country(ies), but not in another, and vice versa. Almost by definition, this will create certain artificial competitive advantages and disadvantages for companies, depending upon at which end they lie in the trade of those particular chemicals. 

The other ACS divisions that served as joint sponsors with the Division of Industrial and Engineering Chemistry and the chairmen provided for three of the four sessions of this symposium should be identified for their helpful assistance Howard M. Peters from the Division of Chemical Information (Chemistry and the Law Subdivision) Kenneth W. Greenlee from the Division of Small Chemical Businesses and Lawrence Keller from the Division of Organic Coatings and Plastics Chemistry. Lawrence Keller served also as co-chairman and helped develop the general scope of the symposium. The Board Committee on Corporation Associates also was a joint sponsor. 

Amination. Very few reactions of general scope exist for the direct conversion of alcohols to amines. Among one of the oldest is the Bucherer reaction which is used to convert naphthols (40) and phenols (41) to their amine derivative by reaction with aqueous sodium bisulphite and ammonia (Reaction XXV). 

There is only one limitation of general scope, namely the possibility for more remote hydrogen abstraction, especially from carbons next to strong electron donors, and for competing intramolecular Paterno-Buchi reaction with appropriately located double bonds. Chapters 3 and 4 cover these processes and may provide the information necessary to determine the likelihood of such reactions competing with y-hydrogen abstraction in a particular compound. 

---