Experiments on the Stability of Si-H Bonds in Carbocationic Polymerization

Model Experiments on the Stability of Si-H Bonds in Carbocationic Polymerization 

In a 70 ml culture tube equipped with a Teflon lined cap, 10 ml 0.2 M 7 was mixed with 10 ml 1 M Me3Al in CH2C12 solvent at 22 °C in a dry box under nitrogen atmosphere. After one hour the Me3Al was destroyed by slowly adding methanol to the mixture. The tube was withdrawn from the dry box, and the reaction mixture was washed with ice-cold 0.5 N HC1 solution and water, separated, dried over anhydrous MgS04, solvent was evaporated under vacuum, and the products were analyzed by H1 NMR spectroscopy. 

Using the same technique employed in the previous model study, a series of experiments have been carried out by mixing 15 ml 0.1 M 4 and 15 ml 1.0 M MejAl in CH2C12 at 22° for 15 min at —20° for 10 min and at —50° for 5,10,20, and 60 min. The reactions were terminated by slowly adding prechilled methanol. The products were washed with ice-cold 0.5 N HC1 and distilled water, separated, dried over MgS04, solvent removed under vacuum, and analyzed by H1 NMR and IR spectroscopies. 

60 min. The reactions were terminated and products purified as in the previous model. The products were analyzed by H1 NMR and IR spectroscopies. 

Following the same procedure as in the previous model study, a series of experiments have been carried out by mixing 1.7 mmol 7,1.7 mmol (CH3)3CCl, and 8.5 mmol MejAl in solvent combinations of CT Cl n-CftH = 30 ml/0 ml, 15 ml/15 ml, and 0 ml/30 ml at —50° for 10 min. The reactions were terminated and the products purified as in the previous model. The products were analyzed by H1 NMR spectroscopy. The experiments were repeated by using CH3CH(cp)Cl instead of (CH3)3CC1. 

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