The reaction vessel equipped with a magnetic stirrer and containing 40 mL of the Grignard reagent was thermostatted.
05 mL of silane was added to 15 mL of the Grignard reagent (providing a 20-40-fold excess of the Grignard reagent), and the temperature change of the reaction solution (less than 1[degrees]C) was recorded as a plot of temperature vs.
The first three entries in Table 2 represent a variation of the donor solvent in the Grignard reagent.
Replacement of the n-butyl group by isopropyl in the Grignard reagent increases the equilibrium constant by a factor of two in accordance of increasing hindrance to coordination with the donor.
Replacement of an ethoxy group by isopropyl in the silane, and particularly the substitution of alkyl groups in the Grignard reagent, leads to a decrease in rate constants by more than two powers of ten.
Pseudo-first-order rate constants in toluene at 20[degrees]C Silane Grignard reagent Titrated conc.
Grignard reagents in ether-toluene mixtures were prepared by dilution of the stock solutions with appropriate amounts of toluene.