Benzoyl peroxide derivatives

A RESEARCH NOTE ON SEMIEMPIRICAL AND DFT MODELING OF THE IR SPECTRA OF BENZOYL PEROXIDE DERIVATIVES... 

There is a linear dependence between experimental (v p) and calculated by the PM6 method values of the normal vibrations frequencies of carbonyl groups of the benzoyl peroxide derivatives (Fig. 11.3). 

Such reactions can be initiated by free radicals, derived from compounds (initiators) such as benzoyl peroxide, ammonium persulphate or azobis-isobutyronitrile or by ionic mechanisms... 

PMMA-impregnated sol—gel-derived siUca gels have also been examined (54). Long-wave uv illumination was employed in addition to benzoyl peroxide for PMMA polymerization. This method prohibited the degradation of the siUca xerogel from moisture adsorption and desorption. Overall the material behaved more like bulk PMMA than bulk siUca, with the exception of hardness. 

Derivative Formation. Hydrogen peroxide is an important reagent in the manufacture of organic peroxides, including tert-huty hydroperoxide, benzoyl peroxide, peroxyacetic acid, esters such as tert-huty peroxyacetate, and ketone derivatives such as methyl ethyl ketone peroxide. These are used as polymerization catalysts, cross-linking agents, and oxidants (see Peroxides and peroxide compounds). 

Benzoyl chloride is an important benzoylating agent. In this use the benzoyl radical is introduced into alcohols, phenols, amines, and other compounds through the Friedel-Crafts reaction and the Schotten-Baumaim reaction. Other significant uses are in the production of benzoyl peroxide [94-56-0], benzophenone [119-61-9], and in derivatives employed in the fields of dyes, resins, perfumes, pharmaceuticals, and as polymerization catalysts. 

Few CIDNP studies on free radical reactions with olefins and related unsaturated molecules have been reported, and relatively little chemically useful information seems to have been derived, despite the potential relevance in polymerizing systems. Thus CIDNP has been reported in the decomposition of benzoyl peroxide in the presence of styrene and... 

The Instantaneous values for the initiator efficiencies and the rate constants associated with the suspension polymerization of styrene using benzoyl peroxide have been determined from explicit equations based on the instantaneous polymer properties. The explicit equations for the rate parameters have been derived based on accepted reaction schemes and the standard kinetic assumptions (SSH and LCA). The instantaneous polymer properties have been obtained from the cummulative experimental values by proposing empirical models for the instantaneous properties and then fitting them to the cummulative experimental values. This has circumvented some of the problems associated with differenciating experimental data. The results obtained show that ... 

Another differential reaction is copolymerization. An equi-molar mixture of styrene and methyl methacrylate gives copolymers of different composition depending on the initiator. The radical chains started by benzoyl peroxide are 51 % polystyrene, the cationic chains from stannic chloride or boron trifluoride etherate are 100% polystyrene, and the anionic chains from sodium or potassium are more than 99 % polymethyl methacrylate.444 The radicals attack either monomer indiscriminately, the carbanions prefer methyl methacrylate and the carbonium ions prefer styrene. As can be seen from the data of Table XIV, the reactivity of a radical varies considerably with its structure, and it is worth considering whether this variability would be enough to make a radical derived from sodium or potassium give 99 % polymethyl methacrylate.446 If so, the alkali metal intitiated polymerization would not need to be a carbanionic chain reaction. However, the polymer initiated by triphenylmethyl sodium is also about 99% polymethyl methacrylate, whereas tert-butyl peroxide and >-chlorobenzoyl peroxide give 49 to 51 % styrene in the initial polymer.445... 

Benzoylacetanilide couplers, 79 253 Benzoyl chloride, 3 595, 634 end use of chlorine, 6 134t physical constants of ring-chlorinated derivatives, 6 333t Benzoylcyclohexane-diones, 73 294 Benzoyloxy radicals, 74 281 Benzoyl peroxide (BPO), 3 634 20 105 hazards associated with, 78 491 uses for, 78 496... 

In a simulated atmosphere, direct epoxidation by ozone led to the formation of benzo[a]pyrene-4,5-oxide. Benzo [a] pyrene reacted with benzoyl peroxide to form the 6-benzoyloxy derivative (quoted, Nikolaou et al, 1984). It was reported that benzo [a] pyrene adsorbed on fly ash and alumina reacted with sulfur dioxide (10%) in air to form benzo[a]pyrene sulfonic acid (Nielsen et al., 1983). Benzo [a] pyrene coated on a quartz surface was subjected to ozone and natural sunlight for 4 and 2 h, respectively. The compounds 1,6-quinone, 3,6-quinone, and the 6,12-quinone of benzo[a]pyrene were formed in both instances (Rajagopalan et al., 1983). 

The rate expression Eq. 3-32 requires a first-order dependence of the polymerization rate on the monomer concentration and is observed for many polymerizations [Kamachi et al., 1978], Figure 3-2 shows the first-order relationship for the polymerization of methyl methacrylate [Sugimura and Minoura, 1966], However, there are many polymerizations where Rp shows a higher than first-order dependence on [M], Thus the rate of polymerization depends on the -power of the monomer concentration in the polymerization of styrene in chlorobenzene solution at 120°C initiated by t-butyl peresters [Misra and Mathiu, 1967]. The benzoyl peroxide initiated polymerization of styrene in toluene at 80°C shows an increasing order of dependence of Rp on [M] as [M] decreases [Horikx and Hermans, 1953], The dependence is 1.18-order at [M] = 1.8 and increases to 1.36-order at [M] = 0.4. These effects may be caused by a dependence of the initiation rate on the monomer concentration. Equation 3-28 was derived on the assumption that Rt is independent of [M], The initiation rate can be monomer-dependent in several ways. The initiator efficiency / may vary directly with the monomer concentration... 

There are solid phase enthalpy of formation data for four aromatic acyl peroxides dibenzoyl peroxide and the bis-o- and bis-p-toluyl derivatives and dicinnamoyl peroxide. The last three were reported in the same publication . The first disconcerting observation is that the p-methyl substituted benzoyl peroxide is less stable than the ortho isomer by nearly 50 kJmol. We cannot reconcile the large difference between the enthalpies of formation of these two isomers, especially since the corresponding anhydrides have comparable enthalpies of formation, —521.0 + 7.9 (p ) and —533.5 + 7.9 (o )kJmol . However, they too exhibit an unexpected stability order and were measured by the same... 

The phenomenon of induced decomposition, in which radicals derived from reaction of the solvent with the initiator benzoyl peroxide consume some of the initiator in a chain process, was first elucidated by Bartlett and Nozaki (equation 51), and by Cass. ... 

Acrylated lignin derivatives were copolymerized with MMA and S in dry methylene chloride with benzoyl peroxide and N,N-dimethyl anyline as catalyst. Reaction mixtures were poured onto Teflon molds, the solvent was evaporated at room temperature in the fume hood, and films were cured in an oven at 105°C for 6 hrs. Experimental details and results are given elsewhere (15). 

Adapalene (Differin) is a derivative of naphthoic acid that resembles retinoic acid in structure and effects. It is applied as a 0.1% gel once daily. Unlike tretinoin, adapalene is photochemically stable and shows little decrease in efficacy when used in combination with benzoyl peroxide. Adapalene is less irritating than tretinoin and is most effective in patients with mild to moderate acnevulgaris. 

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