Di-f-butylperoxide

The AH for the homolysis of peroxides is near the bond dissociation energy (30 to 40 kcal/mol), and AS is positive for both peroxides and azo compounds. For example, the entropies of activation for homolysis of di-f-butylperoxide (Eq. 10.41) and AIBN (2,2 -azodiisobutyronitrile Eq. 10.43) are 13.8 and 12.2 eu, respectively. These values are consistent with the increase in disorder at the transition state due to the breaking of the bonds. 

Since the 1950s, other catalysts have been used to polymerize substituted acetylenes [25]. Free radical initiators (e.g., benzoyl peroxide, di-f-butylperoxide) are active catalysts, as are complexes of other transition metals like Ni and Co. Recently, both Rh and Pd cationic complexes have been shown to polymerize monosubstituted acetylenes [119-121]. Thermal polymerizations and y-... 

Table 6 Non-adiabaticity calculations for the homogeneous electron transfer to di-tert-butylperoxide, di-cumylperoxide and f-butyl bromide (t-BuBr).

Isobutane reacts with O2 by a free radical chain process similar to the one for n-butane except that cage combinations of r-butoxy radicals produced by terminating interactions of f-butylperoxy radicals gives di-t-butylperoxide . r-Butoxy radicals which escape the solvent cage undergo )8-scission to give methyl radicals and acetone ... 

MILLER S FUMIGRAIN (107-13-1) Forms explosive mixture with air (flash point 32°F/0°C oc). May polmerize spontaneously unless inhibited (usually with methylhydro-quinone). It may also polymerize on contact with oxygen, heat, strong light, peroxides, or concentrated or heated alkalis. Elevated temperatures, light, alkalis, silver nitrate, and peroxides (e.g., dibenzoyl peroxide, di-tert-butylperoxide) can cause explosive polymerization. 

Free radical polymerization, another example of a chain reaction (this chapter), is quite common and, for many alkenes and dienes, is the preferred method of polymer formation. Typically, as shown in Table 6.3 and Scheme 6.45, the initiator of the free radical process is a peroxide (such as di-fm-butylperoxide [(CH3)3C-0-0-C(CH3)3]). In Scheme 6.45a, the radical polymerization of ethylene (ethene, CH2=CH2) normally carried out at high pressure (>1(F atm) is shown, while as shown in Scheme 6.45b, the radical polymerization of a diene, 2-chloro-l, 3-butadiene [chloroprene, CH2=C(C1)CH=CH2], produces the all tram or (Z)-polymer called neoprene. ... 

Dialkyloxysulfuranyl radical la [14] is obtained by either addition of a methyl radical to di-r-butyl-sulfoxylate (6), by addition of a f-butoxy radical to /-butyl methylsulfenate (7) or via mixed photolysis of a 1 2 mixture of dimethyldisul-fane (8) and di-/-butylperoxide (9) at low temperature (Scheme 3). 

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