Decomposition Studies of Triisopropylantimony and Triallylantimony
UTAH UNIV SALT LAKE CITY DEPT OF MATERIALS SCIENCE AND ENGINEERING
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The pyrolysis of triisopropylantimony C3H73SB and triallylantimony C3H53Sb has been investigated mass-spectrometrically in He and D2 using an SiO2 flow tube reactor at atmospheric pressure. Both temperature and time dependencies of percent decomposition were studied and the reaction products were analyzed. The overall decomposition processes for both compounds were found to be homogeneous and first order. C3H73Sb pyrolyzes at 250-350 deg C with no effect of the ambient gas. However, C3H6, C3H8, and C6H14 2,3- dimethylbutane were produced in He whereas C3H7D appeared in D2. The pyrolysis is believed to begin via bond cleavage to generate the free C3H7 radicals that, in turn, recombine and disproportionate. Isopropyl radicals react slowly with D2, producing the C3H7D detected. For C3H53Sb, the pyrolysis takes place at 100-160 deg C. The only major product is C6HI0 1,5-hexadiene. Both the pyrolysis rate and products were independent of the ambient. Two possible mechanisms, homolysis and reductive coupling, are discussed. Assuming that homolysis is the rate-limiting step for the pyrolysis of both C3H73Sb and C3H53Sb, bond strengths of 30.8 and 21.6 kcalmole for C3H7-Sb and C3H5-Sb were determined from the experimental data. When either C3H73Sb or C3H53Sb was mixed with trimethylindium, a nonvolatile, liquid material, probably an adduct, was formed. Triisopropylantimony, triallylantimony, pyrolysis, OMVPE.
- Organic Chemistry
- Physical Chemistry