Methyl chloride, bonding

As chlorination proceeds from methyl chloride to carbon tetrachloride, the length of the C—Cl bond is decreased from 0.1786 nm in the former to 0.1755 nm in the latter (3). At ca 400°C, thermal decomposition of carbon tetrachloride occurs very slowly, whereas at 900—1300°C dissociation is extensive, forming perchloroethylene and hexachloroethane and Hberating some chlorine. Subjecting the vapor to an electric arc also forms perchloroethylene and hexachloroethane, as well as hexachlorobenzene, elementary carbon, and chlorine. 

The anomeric effect is also present in acyclic systems and stabilizes conformations that allow antiperiplanar (ap) alignment of the C—X bond with a lone-pair orbital of the heteroatom. Anomeric effects are prominent in determining the conformation of acetals and a-alkoxyamines, as well as a-haloethers. MO calculations (4-3IG) have found 4kcal/mol as the difference between the two conformations shown below for methoxy-methyl chloride. ... 

Bonds may also be broken symmetrically such that each atom retains one electron of the pair that formed the covalent bond. This odd electron is not paired like all the other electrons of the atom, i.e. it does not have a partner of opposite spin. Atoms possessing odd unpaired electrons are termed free radicals and are indicated by a dot alongside the atomic or molecular structure. The chlorination of methane (see later) to produce methyl chloride (CH3CI) is a typical free-radical reaction ... 

Levy (Chapter 6) has also explored the use of supercomputers to study detailed properties of biological macromolecule that are only Indirectly accessible to experiment, with particular emphasis on solvent effects and on the Interplay between computer simulations and experimental techniques such as NMR, X-ray structures, and vltratlonal spectra. The chapter by Jorgensen (Chapter 12) summarizes recent work on the kinetics of simple reactions In solutions. This kind of calculation provides examples of how simulations can address questions that are hard to address experimentally. For example Jorgensen s simulations predicted the existence of an Intermediate for the reaction of chloride Ion with methyl chloride In DMF which had not been anticipated experimentally, and they Indicate that the weaker solvation of the transition state as compared to reactants for this reaction In aqueous solution Is not due to a decrease In the number of hydrogen bonds, but rather due to a weakening of the hydrogen bonds. 

Create a bond inventory and estimate the energy change for each reaction. Based on the values that you calculate, which reaction is more suitable for industrial production of methyl chloride Explain. 

M. Abu samha, K. J. Borve, J. Harnes, and H. Bergersen, What can Cls photoelectron spectroscopy tell about structure and bonding in clusters of methanol and methyl chloride. J. Phys. Chem. A 111, 8903 8909 (2007). 

Table 8 The AMI calculated semiclassical secondary a-deuterium KIEs, the stretching and other contribution to the KIEs and the C—Cl transition state bond lengths for the identity SN2 reactions between chloride ion and substituted methyl chlorides.0...

Figure 6. Measured molecular structure of methyl chloride (CH3CI), taken from Jensen (1981). CH3CI is a nearly tetrahedral molecule with symmetry. All C-H bond lengths, H-C-H angles and H-C-Cl angles are identical.

Mechanisms involving glycol bond fission have been proposed for the oxidation of vicinal diols, and hydride transfer for other diols in the oxidation of diols by bromine in acid solution.The kinetics of oxidation of some five-ring heterocyclic aldehydes by acidic bromate have been studied. The reaction of phenothiazin-5-ium 3-amino-7-dimethylamino-2-methyl chloride (toluidine blue) with acidic bromate has been studied. Kinetic studies revealed an initial induction period before the rapid consumption of substrate and this is accounted for by a mechanism in which bromide ion is converted into the active bromate and hyperbromous acid during induction and the substrate is converted into the demethylated sulfoxide. 

The chemical properties of the chlorobenzenes and chloroethylenes differ strikingly from those of saturated aliphatic chlorine compounds and of aromatic compounds with chlorine substituted in a side chain. For example, methyl chloride and benzyl chloride are hydrolyzed by boiling alkali, giving the corresponding alcohols, whereas chlorobenzene is not affected by this treatment. In general there is a pronounced diminution in reactivity of a chlorine atom adjacent to an aromatic nucleus or double bond. 

While ball-and-stick models of molecules are very useful for visualizing the relative positions of the atoms in space, they are unsatisfactory whenever we also want to show how large the atoms are. Actually, atomic radii are so large relative to the lengths of chemical bonds that when a model of a molecule such as methyl chloride is constructed with atomic radii and bond lengths, both to scale, the bonds connecting the atoms are not clearly evident. None-... 

There are two simple ways in which the SN2 reaction of methyl chloride could occur with hydroxide ion. These differ in the direction of approach of the reagents (Figure 8-1). The hydroxide ion could attack chloromethane at the front side of the carbon where the chlorine is attached or, alternatively, the hydroxide ion could approach the carbon on the side opposite from the chlorine in what is called the back-side approach. In either case, the making of the C-O bond is essentially simultaneous with the breaking of the C-Cl bond. The difference is that for the back-side mechanism the carbon and the attached hydrogens become planar in the transition state. 

It is instructive to compare a C-metal bond with e. g. a C-Cl bond. The carbon chlorine bond exists in two forms as a covalent C-Cl and as an ion pair C+, Cl-. The equilibrium between these two forms in compounds such as triphenyl methyl chloride was studied e.g. by A. G. Evans... 

The reaction between ammonia and methyl halides has been studied by using ab initio quantum-chemical methods.90 An examination of the stationary points in the reaction potential surface leads to a possible new interpretation of the detailed mechanism of this reaction in different media, hr the gas phase, the product is predicted to be a strongly hydrogen-bonded complex of alkylammonium and halide ions, in contrast to the observed formation of the free ions from reaction hr a polar solvent. Another research group has also studied the reaction between ammonia and methyl chloride.91 A quantitative analysis was made of the changes induced on the potential-energy surface by solvation and static uniform electric fields, with the help of different indexes. The indexes reveal that external perturbations yield transition states which are both electronically and structurally advanced as compared to the transition state in the gas phase. 

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