2-methyl-2-butyl chloride

Halo-2-methylbutanes (X = F, Cl, Br) all produce the same carbocation upon dissociation, yet one of these halides is unreactive. Calculate the dissociation energies for 2-methyl-2-butyl fluoride and 2-methyl-2-butyl-chloride. (Energies of fluoride and chloride are given at right.) Compare these to the dissociation energy of the corresponding bromo derivative. Which halide is most likely to be unreactive ... 

The first order rate constant for ethanolysis of the allylic chloride 3 chloro 3 methyl 1 butene is over 100 times greater than that of tert butyl chloride at the same temperature... 

The sedimentation and diffusion coefficients for three different preparations of poly(methyl methacrylate) were measuredf in /i-butyl chloride at 35.6 C (= 0) and in acetone at 20 C (> 0) and the following results were obtained ... 

Methyl-l -butene N-Methylbutylamine Methyl butyl ketone Methyl butyrate Methyl cellosolve Methyl cellosolve acetate Methyl chloride... 

Is the electrophilic addition of hydrogen chloride to 2-methyl-propene the reverse of the El or the E2 elimination reaction of fe/t-butyl chloride ... 

Chloro-3-methyl-1-butene tert-Butyl chloride... 

This activation of the ortho position is most strikingly illustrated in the reactivity of 2,5-dimethylthiophene, which competitive experiments have shown to undergo the SnCb-catalyzed Friedel-Crafts reaction more rapidly than thiophene and even 2-methylthiophene. The influence of the reagent on the isomer distribution is evident from the fact that 2-methoxythiophene is formylated and bromi-nated (with A -bromosuccinimide) only in the 5-position. Similarly, although 3-bromo-2-methylthiophene has been detected in the bromi-nation of 2-methylthiophene with bromine, only the 5-isomer (besides some side-chain bromination) is obtained in the bromination of alkylthiophenes with A -bromosuccinimide. ° However, the mechanism of the latter type of bromination is not established. No lines attributable to 2-methyl-3-thiocyanothiophene or 2-methyl-3-chIoro-thiophene could be detected in the NMR spectra of the substitution products (5-isomers) obtained upon thiocyanation with thiocyanogen or chlorination with sulfuryl chloride. 2-Methyl- and 2-ethyl-thiophene give, somewhat unexpectedly, upon alkylation with t-butyl chloride in the presence of Feds, only 5-t-butyl monosubstituted and... 

A mixture of 24 partsof 4,4-bis(p-fluorophenyl)butyl chloride, 20.9 partsof 4-(4-chloro-aXX,a-trifluoro-m-tolyl)-4-piperidinol, 135 partsof sodium carbonate, a few crystals of potassium iodide in 600 parts of 4-methyl-2-pentanone is stirred and refluxed for 60 hours. The reaction mixture is cooled and 150 partsof water is added. The organic layer is separated, dried, filtered and evaporated. The oily residue is crystallized from diisopropylether, yielding 4-(4[Pg.1172]

The ether-forming step is an S -like reaction of the alkoxide ion on the silicon atom, with concurrent loss of the leaving chloride anion. Unlike most Sn2 reactions, though, this reaction takes place at a tertiary center—a trialJkyl-substituted silicon atom. The reaction occurs because silicon, a third-row atom, is larger than carbon and forms longer bonds. The three methyl substituents attached to silicon thus offer less steric hindrance to reaction than they do in the analogous ferf-butyl chloride. 

The presence of chlorine and/or bromine is easily detected by their characteristic isotopic patterns (see Appendix 11). As in many aliphatic compounds, the abundance of the molecular ion decreases as the size of the R group increases. For example, in the El mass spectra of methyl chloride and ethyl chloride, the molecular ion intensities are high, whereas in compounds with larger R groups such as butyl chloride, the molecular ion peak is relatively small or nonexistent. 

Trimethyl-l-pentene, methyl iodide, f-butyl chloride, r-butyl bromide (Matheson Coleman and Co.) and f-butyl iodide (Eastman Kodak) were obtained in highest purity and were distilled over calcium hydride or molecular sieves and stored at Dry-Ice temperature. 

Schrauzer and co-workers have studied the kinetics of alkylation of Co(I) complexes by organic halides (RX) and have examined the effect of changing R, X, the equatorial, and axial ligands 148, 147). Some of their rate constants are given in Table II. They show that the rates vary with X in the order Cl < Br < I and with R in the order methyl > other primary alkyls > secondary alkyls. Moreover, the rate can be enhanced by substituents such as Ph, CN, and OMe. tert-Butyl chloride will also react slowly with [Co (DMG)2py] to give isobutylene and the Co(II) complex, presumably via the intermediate formation of the unstable (ert-butyl complex. In the case of Co(I) cobalamin, the Co(II) complex is formed in the reaction with isopropyl iodide as well as tert-butyl chloride. Solvent has only a slight effect on the rate, e.g., the rate of reaction of Co(I) cobalamin... 

The solubility properties of Ni11 salen complexes can be varied by appropriate substituents. A choice of ligands containing /-butyl or methyl(triphenylphosphonium chloride) substituents at the aromatic rings (Figure 12) provides a series of Ni11 complexes with solubility adjustable for most commonly used solvents including water.1160... 

By contrast, hydrolysis of the tertiary halide 2-chloro-2-methyl-propane (3,t-butyl chloride) in base is found kinetically to follow equation [2], i.e. as the rate is independent of [eOH], 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 ... 

Fig. 20 Reaction pathways in the reduction of methyl (a) and /-butyl chloride (b) by NO". , reactant and products , transition states. In (a) and (b), the full line is the mass-weighted IRC path from the reactant to the product states the dashed line is a ridge separating the Sn2 and ET valleys and the dotted-dashed line is the mass-weighted IRC path from the Sn2 product state to the ET product state (homolytic dissociation). The dotted line in (a) represents the col separating the reactant and the SN2 product valleys. The dotted line in (b) represents the steepest descent path from the bifurcation point, B, to the Sn2 product. In (a), B is the point of the col separating the reactant and the SN2 product valleys where the ridge separating the SN2 and ET valleys starts.

Hamasaki and coworkers87 investigated the genotoxicity of 14 organic tin compounds (methyl-, butyl- and phenyltins) and inorganic tin (SnCU) on Escherichia coli and on Bacillus subtilis. Dibutyltin dichloride, tributyltin chloride, tributyltin chloride, bis(tributyl-tin)oxide, dimethyltin dichloride and trimethyltin chloride were all found to be genotoxic. 

Organic solvents inhaled by abusers include gasoline, glue, aerosols, amyl nitrite, butyl nitrite, typewriter correction fluid, lighter fluid, cleaning fluids, paint products, nail polish remover, waxes, and varnishes. Chemicals in these products include nitrous oxide, toluene, benzene, methanol, methylene chloride, acetone, methyl ethyl ketone, methyl butyl ketone, trichloroethylene, and trichloroethane. 

Full dissolution has been reported to proceed in ionic liquids such as butyl- or allyl-methyl-imidazolium chloride under microwave irradiation [59, 60], The Clanton is claimed to be essential to favor the de-agglomerization of the cellulose by breaking its H-bonds that hold it together [61]. The cellulose can subsequently be precipitated from the ionic liquid upon addition of, for example, water, without significant depolymerization. 

DTBN with a quantum yield of 1.7. The products of the photoreaction are 2-methyl-2-nitrosopropane 285, isobutylene, terf-butyl chloride, di-terf-butyltrichloromethoxyamine 286 and di-terf-butylhydroxylammonium chloride 287 (equation 130). 

Irradiation at the DTBN-chloroform charge-transfer absorption yields151 285 ( = 1.01), 287 (4> = 0.6), terf-butyl chloride (4> = 0.06), isobutylene (tfi = 0.99) and di-terf-butyl (dichloromethoxy) amine 288 (4> = 0.56) (equation 131). Also151, irradiation of DTBN at 300 nm in methylene chloride gives 2-methyl-2-nitrosopropane and di-terf-butyl-terf-butoxyamine (

products characteristic of the locally excited (mi ) state, and also 2-methyl-2-nitrosopropane (

terf-butyl chloride (

terf-butyl (chloromethoxy) amine 289 (

charge-transfer state. 

The Friedel-Crafts alkylation of 2,5-dimethylthiophene was also studied (57). In contradistinction to thiophene itself, it was reported that this substituted thiophene alkylated readily with only a minor amount of polymerization when an active halide such as t-butyl chloride was used. With less reactive halides, e.g. n-butyl chloride, some replacement of the methyl groups in 2,5-dimethylthiophene occurred and polymerization increased. 

The reaction of CIO- with methyl chloride can only proceed via the Sn2 process. An inverse KIE of 0.85 is measured (Table 10.3). The reaction with /-butyl chloride presumably proceeds via an E2 mechanism (since Sn2 attack on the Cl substituted carbon is blocked) and the observed KIE of 2.31 (Table 10.3) is consistent with that conclusion. The isotope effects for both species are nearly the same as the effects measured in the condensed phase (compare Tables 10.3 and 10.4) and measure the relative contributions of the two paths. The results indicate that the E2 pathway becomes the dominant channel as the substrate becomes more sterically hindered. 

Table 10.4 Deuterium and heavy atom KIEs for methyl and 1-butyl chloride solvolysis in water at 350 K...

Nakane ei al. (1964) established equilibrium constants of boron isotope exchange between boron trifluoride gas on one side and boron trifluoride methyl fluoride, methyl chloride, isopropyl chloride and t-butyl chloride. The value of the equilibrium constants, which represents the thermodynamic isotope effect, was related to the polarity, stability and catalytic activity of the complexes. 

---