The very-low-pressure pyrolysis (VLPP) of n-propyl nitrate, tert-butyl nitrite, and methyl nitrite. Rate constants for some alkoxy radical reactions

✍ Scribed by G. David Mendenhall; David M. Golden; Sidney W. Benson

• Publisher: John Wiley and Sons
• Year: 1975
• Tongue: English
• Weight: 527 KB
• Volume: 7
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550070509

✦ Synopsis

The pyrolysis of n-propyl nitrate and tert-butyl nitrite at very low pressures (VLPP technique) is reported. For the reaction n-PrON02 A nPrO + NO2 the high-pressure rate expression at 300"K, log k, (sec-l) = 16.5 -40.0 kcal/mole/2.3 RT, is derived. The reaction tert-BuONO -% tert-BuO + N O was studied and the high-pressure parameters at 300°K are log kz(sec-') = 15.8 -39.3 kcal/mole/2.3 RT. From aSP,-1 and AS:,-, and the assumption EP1 and E-2 'v 0, we derive log kLl(M-l.sec-l) (300'K) = 9.5 and log

In contrast, the pyrolysis of methyl nitrite and methyld S nitrite afford N O and HIVO and DNO, respectively, in what appears to be a heterogeneous process. The values of k-l and k--5 in conjunction with independent measurements imply a value at 300°K for CHaO + 0 2 CHzO + HO2 of 3.5 X l o 5 M-' .sec-', which is two orders of magnitude greater than currently accepted values.

[n the high-pressure static pyrolysis of dimethyl peroxide in the presence of KOz, the yield of methyl nitrate indicates that the combination of methoxy radicals with NO2 is in the high-pressure limit at atmospheric pressure.