Kinetic isotope effects have been determined for the E2 reaction of some 2-arylethyltrimethyl-ammonium ions with ethoxide in ethanol at 40°. The nitrogen effect, (k14/k15 − 1)100, decreased with increasing electron-withdrawing ability of the para substituent; i.e. 1.37, 1.33, 1.14, and 0.88 for p-OCH3, p-H, p-Cl, and p-CF3, respectively. Furthermore, the primary hydrogen–deuterium isotope effects increased for the same substituents, respectively; i.e. kH/kD = 2.64, 3.23, 3.48, and 4.16. A large positive ρ value of 3.66 was found as well as a small secondary α-deuterium effect of 1.02 for p-H. In addition, the nitrogen isotope effect decreased with increasing strength of the abstracting base for the reaction of ethyltrimethylammonium ion; i.e. 1.86 and 1.41 at 60° for reaction with EtO−–EtOH and t-BuO−–t-BuOH, respectively. The results are discussed in terms of recent theoretical treatments of the effect of base, substituents, and nature of the leaving group on the nature of the transition state for an E2 process. The conclusion is reached that any structural change which causes one bond (C—H) to be weakened more at the transition state will have a corresponding effect on the other bond [Formula: see text]

A study has been made of the liquid-phase oxidation of p-cymene with elemental oxygen using emulsion and photochenlical procetlures with the object of determining ( a ) the nature of thc resulting hydroperoxides and their decomposition products, and (b) the relative activity of the methyl and isopropyl side chains.The followi~~g cornpounds have bee11 shown to be present in the e m u l s i o~~ oxidation product: 2-p-tolyl-2-propyl hydroperoxide, 2-p-tolyl-2-propanol, pisopropylbenzyl alcohol, p-methylacetophenone, curnic acid, p-(a-hydroperoxyisopropyl) benzoic acid, p-(a-hydroxyisopropyl) benzoic acid, and p-acetylbenzoic acid. The two hydroperoxides have been isolated and characterized. By chromatographic separation of the carboxylic acids and fractional distillation of the alcohols formed by lithium aluminum hpdride reduction of all other products, the relative susceptibility of the methyl and isopropyl groups to oxidative attack has been shown to be 1:4.In the photochemical oxidation, hydroperoxide decomposition was very small and the product was shown to consist of 20% p-isopropylbenzpl hyclroperoxide and 80% of 2-P-tolyl-2-propyl hydroperoxide. T h e relative extcnt of oxidative attack at the two positions was therefore identical in the two oxidations.

The n.m.r. spectra of phenol, anisole, and other phenols and aromatic ethers in solution in fluorosulphuric acid and in 70% perchloric acid show that in every case they protonate on an aromatic carbon. Earlier evidence from ultraviolet spectroscopy that phenol and anisole protonate on oxygen is reinterpreted.

a-I-Iydrogen elimination:The substitution reaction on carbon has beell shown (2) to follow either tlic S,l or the SN2 nlechanism, the factors determining the course of reactioil being analogous to those for alkyl halides. For example, in goy0 ethanol the rate of reactioil of tert-butyl nitrate is first order, being independent of the hydroxide ion concentration, while for ethyl nitrate the rate is second order, being proportional to both the nitrate and the hydroxide ion coilceiltrations. Evidence for substitution on nitrogen (reaction 2) is based on oxygeil-18 studies of the position of bond fissioil in the hydrolysis of n-butpl and n-octyl nitrate (4) and on stereocliemical studies in the hydrolysis of optically active 2-octyl nitrate (5). This reaction differs from the others in that it results in the nitration of the base, and this property has been utilized as a synthetic method for the nitration of amines and active ~nethylene groups (6, 7). The P-hydrogen elimination of 'ililanziscri)l receiz~ed Azlglrsl 16, 1960. Conlribz~lion fro711 the B~rrke Chemical Laboratories, Ha?~zillon College, McMaster U?zioerslty, Ha~~czltorz, Outario. zNalro?lal Resear~W Cozr?zcil of Canada Postdoclorate Fellow 1858

The dehydration of butanediol-2,3 over activated Morden bentonite has been investigated. Below 350 °C., liquid products butanone-2, isobutyraldehyde, and the isobutyral of butanediol-2,3 were produced. Butanone-2 was obtained in 86% yield. At higher temperatures, 450° to 700 °C., gaseous decomposition occurred. Only small amounts of butadiene were formed from the dry glycol while a 25% diolefin yield resulted using water vapour as diluent. The decomposition of dry butanone-2 over bentonite gave only traces of butadiene. Yields of diolefin increased using water as diluent, 44.8% being obtained at 700 °C. with a ketone–water molar ratio of 1 to 40. Butanone-2 was considered intermediate in the formation of butadiene from butanediol-2,3.