Triethylamine ethyl iodide reaction

Reaction of ethyl iodide with triethylamine [(CH3CH2)3N ] yields a crystalline compound CgH2oNI in high yield This compound is soluble in polar solvents such as water but insoluble in nonpolar ones such as diethyl ether It does not melt below about 200°C Suggest a reasonable structure for this product... 

Table 8-S. Kinetic Data on the Menschutkin Reaction of Triethylamine and Ethyl Iodide at 25°C...

Table 8-10 gives pertinent data for the Menschutkin reaction of triethylamine with ethyl iodide. These reactant molecules are volatile, so their transfer free energies were determined by a gas chromatographic variation of the vapor pressure method. For this reaction Eq. (8-57) is written... 

Figure 8-6. Ploi according to Fig. 8-5 of transfer free energies of the transition state (ordinate) and reactant state (abscissa) for the Menschutkin reaction of triethylamine and ethyl iodide. The reference solvent is N, Af-dimethylformamide (No. 27). Data are from Table 8-10, where the solvents are identified by number. Closed circles are polychlorinated solvents.

These predictions of effect of solvent polarity on reaction rates were first made by Hughes and Ingold in 1935. They searched the literature of direct displacement reactions and found that for charge types 1-3 the experimental facts agreed with their predictions. For example, the reaction of ethyl iodide with triethylamine (Equation 4.9) an SN2 displacement of type 2, does proceed more... 

The kinetics of the reaction between bromopropionate and thiosulfate ions have been studied at 10-40 °C in various ethanol-water mixtures.107 Activation parameters were evaluated as a function of ionic strength and dielectric constant of the medium. The medium effect of mixed solvents on the rate constants of the Menshutkin reaction of triethylamine with ethyl iodide has been studied for binary mixtures of cyclohexane with benzene or ethyl acetate,108 and with chlorobenzene or dimethoxyethane.109 Rates were measured over the temperature range 293.1-353.1 K, and activation parameters were determined. 

Using the unshared electron pair on its nitrogen, triethylamine acts as a nucleophile in an SN2 reaction toward ethyl iodide. 

The probes 7 and 2-nitro-/V-methylaniline (82) were employed by Nigam and coworkers114 to characterize aqueous methanol and acetonitrile mixtures, and the authors modeled these solutions in terms of the contributions from the water, the co-solvent and the presumed complex formed between them. Mixtures of a non-polar solvent (cyclohexane) and a highly polar one (nitrobenzene) were studied by Nevecna and Bekarck115 by means of /V,/V-dimethyl-4-nitrosoaniline (47). The spectral shifts were found to correlate well with the rate constant for the reaction of triethylamine with ethyl iodide. 

Wetzler and coworkers123 employed 4-aminophthalimide (63) and 4-amino-lV-methyl-phthalimide (64) as solvatochromic (and thermochromic) fluorescent probes in solvent mixtures. A bathochromic shift of the emission spectra was found in mixtures of toluene with ethanol and with acetonitrile123 when the more polar solvent was added to toluene, but raising the temperature causes a relative hypsochromic effect. Mixtures of benzene and acetonitrile were studied by Nevecna and coworkers124 for their polarity by means of the probes 46 and 47 and with respect to the correlation of this with the rate constants of the reaction of triethylamine with ethyl iodide. The fluorescence of the ammonium salt of 4-(l-naphthylsulfonate)aniline (84) in dioxane and water mixtures was studied by Hiittenhain and Balzer125. 

Optimization of chemical yields can also be achieved by physicochemical activation. It is meant as an activation mode resembling catalysis and involving physicochemical interactions between reactants and medium. The role of the solvent with respect to the course of organic reactions is of obvious importance. One of the first systematic studies reporting the kinetic effect is due to Menshutkin who determined rate constants for the addition of ethyl iodide to triethylamine [49]. This is a typical example of an ionogenic reaction in which the stability of the transition... 

Preparation. This iodide can be prepared in 60% yield by the reaction of ethylidene chloride (Aldrich) with ethyl iodide and aluminum chloride. It can also be prepared by the reaction of acetaldehyde hydrazone with iodine and triethylamine (4, 260). This method is based on the procedure of Pross and Sternhell. ... 

For the reaction between ethyl iodide and triethylamine, the frequency factor in various solvents, at 100 °C, ranges between 2 x 10 and 1 x 10 L/mol s. Calculate the range of AS for the reaction. 

The influence of benzene and ether as solvents on the velocity of the ester formation is similar to their influence on the reaction between triethylamine and ethyl iodide described in Chapter V. 

The reaction which produces diethylamine also yields as byproducts ethylamine and triethylamine. The relative amounts of each compound produced depends upon the molar ratio of the two starting materials. Use of only a little ethyl iodide favors the formation of mostly ethylamine. Use of a lot of the ethyl iodide favors the formation of triethylamine. Somewhere in the middle, a roughly even split occurs. This will be done here. See Journal of the American Chemical Society Volume 69, pages 836 to 838 (1947)... 

FIGUBJi 5.8 Relationship between the rate constants for the reaction between ethyl iodide and triethylamine and the solubility parameters of the solvents. (Constructed using the rate constants given by Laidler (1965).)... 

Kinetics so closely related to the solvent effeet as those of the Menschutkin reaction between triethylamine and ethyl iodide [eq. (10.3.27)], the solvolysis of tert-butyl chloride [eq. (10.3.28)] or the deearboxylation of 3-carboxybenzisoxazole [eq. (10.3.29)], are ac-eeptably described by our scales. 

The rate of this reaction between triethylamine and ethyl iodide, whieh varies by five orders of magnitude fromn-hexane (1.35xl0MmoT s ) toDMSO (8.78xlO lmoT s ), is aceurately described by solvent polarity and acidity -the sensitivity to flie latter is somewhat imprecise. The equation for the kinetics of solvolysis of tert-butyl chloride is ... 

The reaction studied was the quatemarization of triethylamine by ethyl iodide at 100 °C [N. Menschutkin, Z. Phys. Chem., 6, 41 (1890)]. Menschutkin s first discussion on solvent effects dealt with the reactions between acetic anhydride and alcohols [Z. Pl s. Chem., 1,611 (1887)]. The catalytic role of solvents was already recognized in 1862 by Berthelot and Pean de Saint Gilles in their Recherches sur les Aflinit6s [see, e. g., H. G. Grimm, H. Ruf, and Wolff, Z. Phys. Chem., B13,301 (1931)]. 

In order to explain rigorously whether the effect of solvent on rate is predominantly an effect on the transition state or the products it is necessary to determine the transfer energies of the reactants between the solvents concerned, as well as the reaction rates. This has only been done in a few cases, the most thoroughly studied example being the quaternisation of tertiary amines [12]. Some reaction rate constants for the quaternisation of triethylamine with ethyl iodide in a variety of solvents are shown in Table 12.9. 

This work was continued later on by Menshutkin in Petersburg in 1890, who studied the quaternization of tertiary amines with alkyl halides - a reaction which now is commonly known as the Menshutkin reaction . Menshutkin found, for example, that the reaction rate between triethylamine and ethyl iodide increases with solvent polarity, up to a factor of 742 in benzyl alcohol relative to n-hexane as solvent(3). 

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