Neopentane, thermal decomposition

Tt is well known that HCl can serve as a catalyst in free radical reactions, for example, the thermal decomposition of neopentane (2) and diter-tiary butyl peroxide (3). In these reactions the slow and rate-controlling step is a reaction of the type R + R H — RH -f R where both R and R are polyatomic radicals. The addition of HCl causes the rapid chain process, R -f HCl — RH -f Cl and R H -f Cl - R -f HCl to occur and to accelerate the overall reaction. 

The thermal decomposition of magnesium hydroxide under carefully controlled conditions, followed by subsequent rehydration, has been studied by means of nitrogen and neopentane adsorption isotherm measurements. Up to about 85% decomposition a uniform layered particle structure, consisting of plate-like microcrystallites intercalated by slit-shaped pores of width ca. 0.93 nm, gradually spreads from the outside towards the centre of each crystal. At this stage each particle consists of MgO of normal... 

Thermal treatment of (=SiO)Hf(CH2Bu )3 at increasing temperatures leads to the successive evoluhon of neopentane, isobutene and isobutane as well as several alkanes varying from Cj to C5. Polyisobutenes are also formed on the surface. The mechanism by which such decomposition occurs suggests a succession of y-H eliminations with formahon of neopentane followed by P-methyl transfer and formation of isobutene and [Hf]-Me (Scheme 2.14). This isobutene is reinserted into [Hf]-Me with formahon of isopentene and [Hf]-H. 

---