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R-Butyl chloride

There are only few reactions known introducing substituents to the H-bearing nitrogen of oxaziridines. (V-Alkylation of l-oxa-2-azaspiro[2.5]octane (3,3-pentamethylene-oxaziridine 52) with r-butyl chloride to give (53) was carried out for structure proof of (52). This reaction is of no preparative importance, since N-alkylated oxaziridines are easily obtained by ring synthesis. [Pg.204]

Because carbocations are key intermediates in many nucleophilic substitution reactions, it is important to develop a grasp of their structural properties and the effect substituents have on stability. The critical step in the ionization mechanism of nucleophilic substitution is the generation of the tricoordinate carbocation intermediate. For this mechanism to operate, it is essential that this species not be prohibitively high in energy. Carbocations are inherently high-energy species. The ionization of r-butyl chloride is endothermic by 153kcal/mol in the gas phase. ... [Pg.276]

Another example of preferential solvation is provided by the inhibition by dioxane of the aiyl alkylation of phenol by r-butyl chloride. ... [Pg.404]

If Y is to be a valid measure of solvent ionizing power, presumably the defining reaction should proceed via the Lim (pure SnI) process. This was the basis for the original choice of r-butyl chloride. It is now believed that /-butyl chloride sol-volyzes with some solvent participation, and modern versions of Y are based on other compounds, of which 2-adamantyl tosylate (p-toluenesulfonate, OTs), 6, is the most favored." ... [Pg.431]

We have already encountered the ir, a, and p quantities. The 8h term is inserted to account for the cavity effect. Equation (8-80) is a 12-parameter equation for which considerable generality is claimed, in that it is said to be applicable to chemical rates and equilibria, spectra, solubilities, partition coefficients, and even biological responses. Usually, of course, by judicious selection of solvents, it is possible to reduce the number of parameters by ensuring that some terms are negligible.An example requiring most of the parameters in Eq. (8-80) is the solvolysis/dehydrohalogenation of r-butyl chloride in 21 HBD and non-HBD solvents, for which this correlation was found ... [Pg.444]

An example of the first isolated /3-sultine makes use of this y-cyclization where r-butyl chloride formally acts as the leaving group (73JA3420,75CC724). Of the 13 examples reported, all eliminate S02 readily to give the corresponding alkenes in 50-90% yields (Scheme 72). [Pg.471]

By contrast, hydrolysis of the tertiary halide 2-chloro-2-methyl-propane (3,r-butyl chloride) in base is found kinetically to follow equation [2], i.e. as the rate is independent of [ OH], this can play no part in the rate-limiting step. This has been interpreted as indicating that the halide undergoes slow ionisation (in fact, completion of the R- -Cl polarisation that has already been shown to be present in such a molecule) as the rate-limiting step to yield the ion pair R Cle (4) followed by rapid, non rate-limiting attack by eOH or, if that is suitable, by solvent, the latter often predominating because of its very high concentration ... [Pg.45]

This section deals with the difficult problem of establishing the most plausible initiation mechanism for polymerisation systems in which cocatalysis is ascribed to alkyl or aralkyl halides. This type of cocatalysis is by no means a general phenomenon. We have already mentioned in preceding sections dealing with other types of cocatalysis that, for example, r-butyl chloride is not a cocatalyst in the polymerisation of isobutene induced by titanium tetrachloride and that 1-phenylethyl chloride is not a cocatalyst in conjunction vdth stannic chloride - Indeed, the reaction... [Pg.169]

Y polarity scale. A solvent polarity scale proposed by Grunwald and Winstein [Grunwald and Winstein, 1948] based on solvolytic rate ko of r-butyl chloride in 80 % aqueous ethanol at 25 °C. The Y polarity value for a given solvent is calculated by ... [Pg.265]

For tertiary substrates, e.g. r-butyl chloride (13, l-chloro-1,1-dimethylethane), significant non-bonded steric repulsion prevents an incoming nucleophile from approaching carbon C(l) from the rear to form the collinear arrangement of atoms required in the SN2 reaction. For this reason, tertiary substrates instead undergo the alternative SN1 pathway for substitution. [Pg.128]

The amination reaction is not limited to aromatic hydrocarbons it is also applicable to r-alkanes. r-Butyl chloride reacts with trichloramine in the presence of aluminum chloride to give f-butylamine in 88% yield.5 Methylcyclohexane is converted into 1-amino-1-methylcyclohexane in yields as high as 67% (based on trichloramine). The most satisfactory conditions use C7H14-A1C13-NC13 in a 2 2 1 ratio with methylene chloride as solvent and a temperature of 0 5°.6 Under the same conditions adamantane gives 1 -aminoadamantane in nearly quantitative yield.7... [Pg.489]

All solvents and monomers were purified and stored under nitrogen atmosphere. The r-butyl chloride (r-BuCl, Eastman) was distilled from calcium hydride under nitrogen atmosphere prior to use. Diethylaluminum chloride (Et2 A1C1, Texas Alkyls Co.) was purified by vacuum distillation (bp °C/mm Hg 110/25). Ethyl chloride (EtCl, Linde Division, Union Carbide Co.) was purified by passing through a column packed with Molecular Sieves and barium oxide. The m-3-hexene (Chemical Samples Company) was distilled under nitrogen prior to use. The polybutadiene, Diene 35, from the Firestone Tire and Rubber Company and high 1,2-polybutadiene were purified by reprecipitations from benzene into excess acetone. [Pg.145]

Initiation by aluminum chloride with r-butyl chloride cocatalyst is similarly described by... [Pg.513]

Problem 8.17 Write equations to describe plausible termination reactions in cationic polymerization of isobutylene initiated by (a) BF3.OH2, (b) BCI3.OH2, (c) Al(CH3)3/r-butyl chloride, and (d) Al(C2H5)3/t-butyl chloride. [Pg.517]

Because of their crucial role in the ionization step, solvents have a profound effect on the rates of El reactions. These rates for a number of tertiary halides have been determined in a variety of solvents. For r-butyl chloride there are huge differences in the rates in water (log k = -. 54), ethanol (log k = -7.07), and diethyl ether (log k = — 2.1A)P Similarly, the rates of the El reaction of 1-methylcyclopentyl bromide range from 1 x 10 s in methanol to 2 x 10 s in hexane. Polar aprotic solvents such as DMSO (k = 2x lO s ) and acetonitrile (k = 9x 10 s ) are also conducive for ionization. The solvent properties that are most important are polarity and the ability to assist leaving group ionization. These, of course, are the same features that favor reactions, as we discussed in Section 3.8. [Pg.554]

The reaction rates of toluene and benzene with /-propyl chloride or r-butyl chloride in nitromethane can be fit to a third-order rate law. [Pg.806]


See other pages where R-Butyl chloride is mentioned: [Pg.204]    [Pg.424]    [Pg.198]    [Pg.206]    [Pg.2059]    [Pg.57]    [Pg.865]    [Pg.408]    [Pg.212]    [Pg.64]    [Pg.144]    [Pg.149]    [Pg.177]    [Pg.184]    [Pg.190]    [Pg.13]    [Pg.359]    [Pg.276]    [Pg.89]    [Pg.61]    [Pg.159]    [Pg.330]    [Pg.105]    [Pg.143]    [Pg.361]    [Pg.361]    [Pg.426]   
See also in sourсe #XX -- [ Pg.304 ]




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