Anils, Charging

Figure 7. Linear free energy relations and contact charging. The anils charge positively against steel, 0. The substituted polystyrenes charge negatively against zinc powder, 0.

I he final step is to balance the hydrogen atoms anil the charges by including six protons (in this case) on the left-hand side ... 

By the same token that aza substituents retard electrophilic substitution, so they accelerate nucleophilic substitution,19,20 40 41 particularly when positively charged. In an interesting study based on this type of reactivity, the equilibrium 16 = 17 has been investigated,85 and this and the rate of subsequent ring opening leading to substituted anils of glutaconic aldehyde found to correlate with o. ... 

Similarly small rate factors were obtained for 1,3-dipolar cycloadditions between diphenyl diazomethane and dimethyl fumarate [131], 2,4,6-trimethylbenzenecarbonitrile oxide and tetracyanoethene or acrylonitrile [811], phenyl azide and enamines [133], diazomethane and aromatic anils [134], azomethine imines and dimethyl acetylenedi-carboxylate [134a], diazo dimethyl malonate and diethylaminopropyne [544] or N-(l-cyclohexenyl)pyrrolidine [545], and A-methyl-C-phenylnitrone and thioketones [812]. Huisgen has written comprehensive reviews on solvent polarity and rates of 1,3-dipolar cycloaddition reactions [541, 542]. The observed small solvent effects can be easily explained by the fact that the concerted, but non-synchronous, bond formation in the activated complex may lead to the destruction or creation of partial charges, connected... 

The first term (kinetic energy) is a summation over all the particles in the molecule. The second term (potential enctgy) uses Coulomb s law to calculate the interaction between every pair of particles in the molecule, where e, and cj ate the charges on particles i and j. For electrons, the charge -e, while the charge for a nucleus is Ze, where Z Is the atomic number. The summation nutation ipairwise interaction terms in the summation (e.g., eg / = e e, and should only appear in the potential energy term once). The denominator r in the. second term is the distance between particles i anil j. J. i is understood to be the electronic wave function for a many-atom system. 

The material of construction for the Grignard reactors and feed vessels R-1. R-2, T-1, and T-2 is typiciilly stainless steel, carbon steel or glass-lined cat bon steel. (For convetiiencc the charge tanks anil the reactors are numbered in Figure 6.1. so that T-l refers to Tank I and R-l refers to Reactor I.) The use of carbon steel must be considered carefully, however, due to the potential introduction ol iron which can be a probletn in some reactions. The material of construction for R-3 and T-3, the quench equipment, can be glass-lined steel or an acid resistant metal alloy such as Hastelloy C. 

Figure 2. Hammett plot of triboelectric charging for substituted polystyrenes and salicyl anils.

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