Benzoyl Hydroperoxide

Phthalmonoperacid (or Mono-[2-Carboxy-benzoyl] -hydroperoxide). H0(0)C.C6H4.C(0).0.0.H mw 182.165 ndles mp dec ca 110° with gas evoln, V sol in w or eth si sol in benz or chlf. Prepn is by reacting phthalic anhyd with an excess of hydrogen peroxide at —10°. Explds with brisance on rapid heating or on impact... 

Benzoyl hydroperoxide was used for the conversion of divinyl sulphide into divinyl sulphoxide by Levin as early as 1930. In 1954 Bateman and Hargrave reported that saturated sulphides may be oxidized to sulphoxides by means of cyclohexyl or t-butyl hydroperoxide. These authors found that in both polar and non-polar solvents oxygen transfer occurred to give quantitative yields of sulphoxides over a wide range of experimental conditions according to equation 7. It was also reported that a quantitative yield of sulphoxides was obtained from the reaction of unsaturated sulphides with t-butyl and cyclohexyl hydroperoxides in methanol. With t-butyl hydroperoxide in benzene the sulphoxide yield was in no case stoichiometric, varying from 90 to 5% under the condition chosen. 

Cyclohexene oxide was first prepared by Brunei from o-iodo-cyclohexanol and solid potassium hydroxide.1 It has also been obtained by the oxidation of cyclohexene with benzoyl hydroperoxide.2... 

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). 

Cumene hydroperoxide [95], benzoyl peroxide, or tert-h iiy peroxide [96]. can be used as accelerators with alkylboron initiators. The chain transfer constant for MMA to tributylborane has been estimated to be 0.647, which is comparable to tripropylamine [97]. 

Organic peroxide-aromatic tertiary amine system is a well-known organic redox system 1]. The typical examples are benzoyl peroxide(BPO)-N,N-dimethylani-line(DMA) and BPO-DMT(N,N-dimethyl-p-toluidine) systems. The binary initiation system has been used in vinyl polymerization in dental acrylic resins and composite resins [2] and in bone cement [3]. Many papers have reported the initiation reaction of these systems for several decades, but the initiation mechanism is still not unified and in controversy [4,5]. Another kind of organic redox system consists of organic hydroperoxide and an aromatic tertiary amine system such as cumene hydroperoxide(CHP)-DMT is used in anaerobic adhesives [6]. Much less attention has been paid to this redox system and its initiation mechanism. A water-soluble peroxide such as persulfate and amine systems have been used in industrial aqueous solution and emulsion polymerization [7-10], yet the initiation mechanism has not been proposed in detail until recently [5]. In order to clarify the structural effect of peroxides and amines including functional monomers containing an amino group, a polymerizable amine, on the redox-initiated polymerization of vinyl monomers and its initiation mechanism, a series of studies have been carried out in our laboratory. 

Prepn is by reaction of cyclohexanol (with caution ) with a mixt of 75% H202 and 0.01 vol % of coned sulfuric acid at 0°. The mixt is allowed to stand overnight under refrigeration. The 1-hydroxycyclohexyl 1-hydroperoxide formed (see also Vol 3, C598-L) is then esterified with benzoyl chloride in py at 0°. 

Organic peroxides and hydroperoxides decompose in part by a self-induced radical chain mechanism whereby radicals released in spontaneous decomposition attack other molecules of the peroxide.The attacking radical combines with one part of the peroxide molecule and simultaneously releases another radical. The net result is the wastage of a molecule of peroxide since the number of primary radicals available for initiation is unchanged. The velocity constant ka we require refers to the spontaneous decomposition only and not to the total decomposition rate which includes the contribution of the chain, or induced, decomposition. Induced decomposition usually is indicated by deviation of the decomposition process from first-order kinetics and by a dependence of the rate on the solvent, especially when it consists of a polymerizable monomer. The constant kd may be separately evaluated through kinetic measurements carried out in the presence of inhibitors which destroy the radical chain carriers. The aliphatic azo-bis-nitriles offer a real advantage over benzoyl peroxide in that they are not susceptible to induced decomposition. 

Fig. 13.—Reciprocal of the average degree of polymerization Xn plotted against the rate of polymerization Rp at 60°C for undiluted methyl methacrylate using azo-bis-isobutyro-nitrile (Azo), benzoyl peroxide (BZ2O2), cumene hydroperoxide (CHP), and i-butyl hydroperoxide (i-BPH). (Baysal and...

Benzoyl peroxide is much larger than H202, but the steric effect is apparently not a factor for the highest rate constant k. Assuming that the activation of hydroperoxides by Fem-TAMLs... 

Some times even catalysts can include initiators to decompose into free radicals. In such type of reaction, an electron transfer mechanism is involved. Peroxides and hydroperoxides are decomposed in this way. For example, the decomposition of benzoyl peroxide by an aromatic tertiary amine at room temperature. 

Irradiation of toluene in the presence of chlorine yielded benzyl hydroperoxide, benzaldehyde, peroxybenzoic acid, carbon monoxide, carbon dioxide, and other unidentified products (Hanst and Gay, 1983). The photooxidation of toluene in the presence of nitrogen oxides (NO and NO2) yielded small amounts of formaldehyde and traces of acetaldehyde or other low molecular weight carbonyls (Altshuller et al, 1970). Other photooxidation products not previously mentioned include phenol, phthalaldehydes, and benzoyl alcohol (Altshuller, 1983). A carbon dioxide yield of 8.4% was achieved when toluene adsorbed on silica gel was irradiated with light X >290 nm) for 17 h (Freitag et ah, 1985). 

Fig. 3-5 Dependence of the degree of polymerization of styrene on the polymerization rate. The effect of chain transfer to initiator is shown for t-butyl hydroperoxide (o), cumyl hydroperoxide ( ). benzoyl peroxide ( ), and azobisisobutyronitrile ( ) at 60°C. After Baysal and Tobolsky [1952] (by permission of Wiley-Interscience, New York).

Wheat flour, dibenzoyl peroxide determination, 698, 701 Workplace air benzoyl peroxide, 701 peracetic acid, 699 Wurster s reagent, hydroperoxide determination, 678, 684... 

Butyl hypochlorite, 55 of phenols to quinones Benzoyl /-butyl nitroxide, 28 2,3-Dichloro-5,6-dicyano-l, 4-benzoqui-none, 104 Periodic acid, 238 of phosphorus compounds Dimethyldioxirane, 120 of selenium compounds Potassium permanganate, 258 of sulfides to sulfoxides and sulfones /-Butyl hydroperoxide-Dialkyl tar-trate-Titanium(IV) isopropoxide, 51 ra-Chloroperbenzoic acid, 76, 112 Dimethyldioxirane, 120 of thiols to sulfur compounds Trimethylsilyl chlorochromate, 327... 

Organic peroxides acyl peroxides (benzoyl, acetyl, lauryl peroxides, etc), alkyl peroxides, hydroperoxides, etc. are used as polymerization initiators. Azocompounds (for example, redox systems, etc. are also widely used as initiators. In... 

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