Acetyl Benzoyl Peroxide Research Articles

Femtosecond Infrared Spectroscopy of Aroylperoxide Photofragmentation – Site Selective Decarboxylation

Abstract The ultrafast photofragmentation of acetyl-benzoyl peroxide (ABPO) and 2-naphthoyl-benzoyl peroxide (NBPO) after UV excitation at 266 nm is studied by mid-infrared transient absorption spectroscopy. 13C-isotopic labelling is employed to unravel the primary fragmentation paths. For NBPO it appears that excitation of the benzoyloxy part causes decarboxylation exclusively at that site. In ABPO the acetyloxy part completely decarboxylates upon 266 nm excitation while only 80% – 85% of the benzoyloxyl radicals formed decarboxylate. The remaining radicals either combine with methyl radicals to methylbenzoate within about 30 ps or survive on the time scale of the experiment (1.5 ns). Photofragmentation of ABPO occurs from the S1-state whose lifetime is about 200 fs. All fragmentation products including CO2 also appear on this time scale.

NMR analysis of diacyl peroxide decomposition in methanol in response to temperature and microwave radiation

We have studied the decomposition of benzoyl and acetyl benzoyl peroxides in methanol-d4 in response to temperature and microwave radiation. We have shown that chemically-induced dynamic nuclear polarization (CIDNP) can be observed even when the reactions are carried out in spectrometers with high magnetic fields. In this case, spin correlation persists in geminal radical pairs involving labile acyloxyl radicals. Regardless of the method used to initiate peroxide decomposition, the same amount of products are formed. Homolysis occurs according to a chain mechanism. The contribution of induced decomposition decreases over the course of the reaction. Dissolved oxygen molecules efficiently terminate the chain, decreasing the rate of peroxide decomposition. In the case of acetyl benzoyl peroxide, the product yield depends on the initiation mechanism: for microwave irradiation, the solvent molecules are more active while dissolved oxygen is less active than in thermolysis.

Analysis of diacyl peroxides by Ag + coordination ionspray tandem mass spectrometry: free radical pathways of complex decomposition

Organic peroxides have significance in organic synthesis and biological processes. Characterization of these compounds with weak O–O bonds is sometimes difficult due to their thermal instability and sensitivity to acid or base. Coordination of diacyl peroxides with AgBF 4 provides a means for analysis of these compounds by coordination ionspray tandem mass spectrometry (CIS-MS/MS). Precursor ion (Q 1) scans of acetyl benzoyl peroxide give two Ag + adducts, [M + Ag + solvent] + and [M + Ag + M] +. These silver ion adducts can be selectively dissociated (CID) to give unique structural information about the analyte. Decomposition of the [M + Ag + solvent] + adduct generates fragmentation products due to apparent homolytic cleavage of the O–O bond followed by decarboxylation of the resultant radicals. The bis-diacylperoxide complex, [M + Ag + M] + gives CID pathways that involve homolysis of the O–O bond and free radical cross-coupling of the two diacyl peroxides coordinated to the silver ion, i.e. formation of dibenzoyl peroxide, phenyl benzoate, and biphenyl from acetyl benzoyl peroxide. The observation of free radical CID modes is uncommon in mass spectrometry but these pathways are consistent with well-known solution and gas phase processes for peroxide compounds. The proposed fragmentation pathways have been supported by experiments with 18O and deuterated substrates. This technique can be applied to analyze diacyl peroxides with different substituents as well.

ChemInform Abstract: Controlled C‐5 Methylation of Caffeine by Benzoyloxy Radical Addition at C‐8.

Abstract C-5 methylation of the model purine compound caffeine by acetyl benzoyl peroxide is the result of preferential addition of the electrophilic benzoyloxy radical at C-8 in neutral medium. X-ray structure and molecular orbital calculations on 1,3,5,7-tetramethyl-5,7-dihydrouric acid are presented.

Using Molecular Mechanics to Model the Movement and Relaxation of Radical Pairs Created By Photolysis of Single Crystals of Acetyl Benzoyl Peroxide (ABP)

Abstract The structure of isolated crystal defects is studied by molecular mechanics techniques, using experimental data to constrain the relaxation of configurational energy and to escape from local energy minima. A “Surface Walking” algorithm helps determine the reaction path among the metastable intermediate structures that evolve upon warming. Applying these techniques to ABP gives good results even without relaxing surrounding molecules.

Controlled C-5 methylation of caffeine by benzoyloxy radical addition at C-8

C-5 methylation of the model purine compound caffeine by acetyl benzoyl peroxide is the result of preferential addition of the electrophilic benzoyloxy radical at C-8 in neutral medium. X-ray structure and molecular orbital calculations on 1,3,5,7-tetramethyl-5,7-dihydrouric acid are presented.

MNDO analysis of aliphatic diacyl peroxide conformation

We have examined the molecular geometry of the last by SCF MO LCAO in the MNDO approximation [3] for diacetyl peroxide (I), acetyl propionyl peroxide (II), and acetyl-2-methyl propionyl peroxide (III). In calculations on I, the bond lengths and angles were taken as identical in accordance with the C 2 symmetry. The rotations around the C-O bonds were taken as independent. For III, it was assumed that the CH 3 groups retain their tetrahedral structure. The geometrical parameters for both such groups in the hemmethyl moiety were taken as identical. In the optimization of II, no assumptions were made about symmetry retention in any of the~parts. The calculations were compared with measurements via ones on the geometry on acetyl benzoyl peroxide (IV). A planar structure was assumed for the phenyl moiety, while all the other parameters were taken as independent.

ChemInform Abstract: Direct Photolysis of Acetyl Benzoyl Peroxide, Dibenzoyl Peroxide, and Perbenzoic Acid.

ChemInform Abstract: Direct Photolysis of Acetyl Benzoyl Peroxide, Dibenzoyl Peroxide, and Perbenzoic Acid.

Direct photolysis of acetyl benzoyl peroxide and benzoyl peroxide

The quantum yields were found for the photodissociation of the O-O bond for acyl peroxides (0.12–0.14). In the framework of our assumptions, the increase in ϕ with increasing peroxide concentration may be related to conversion of the triplet excimer.

Photolysis of acetyl benzoyl peroxide isolated in an argon matrix: the stability of the benzoyloxy and acetoxy radicals towards decarboxylation

Photolysis of acetyl benzoyl peroxide isolated in an argon matrix: the stability of the benzoyloxy and acetoxy radicals towards decarboxylation

過酸化アセチルベンゾイルのカルボン酸による酸触媒交換アシル化反応

過酸化アセチルベンゾイルのカルボン酸による酸触媒交換アシル化反応

ChemInform Abstract: LOW TEMPERATURE PHOTOCHEMICAL STUDIES ON ACETYL BENZOYL PEROXIDE. OBSERVATION OF METHYL AND PHENYL RADICALS BY MATRIX ISOLATION INFRARED SPECTROSCOPY

Chemischer InformationsdienstVolume 7, Issue 5 Preparative Organic Chemistry ChemInform Abstract: LOW TEMPERATURE PHOTOCHEMICAL STUDIES ON ACETYL BENZOYL PEROXIDE. OBSERVATION OF METHYL AND PHENYL RADICALS BY MATRIX ISOLATION INFRARED SPECTROSCOPY J. PACANSKY, J. PACANSKYSearch for more papers by this authorJOACHIM BARGON, JOACHIM BARGONSearch for more papers by this author J. PACANSKY, J. PACANSKYSearch for more papers by this authorJOACHIM BARGON, JOACHIM BARGONSearch for more papers by this author First published: February 3, 1976 https://doi.org/10.1002/chin.197605109AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume7, Issue5February 3, 1976 RelatedInformation

Low temperature photochemical studies on acetyl benzoyl peroxide. Observation of methyl and phenyl radicals by matrix isolation infrared spectroscopy

Low temperature photochemical studies on acetyl benzoyl peroxide. Observation of methyl and phenyl radicals by matrix isolation infrared spectroscopy

X-ray and electron paramagnetic resonance structural investigation of oxygen discrimination during the collapse of methyl-benzoyloxy radical pairs in crystalline acetyl benzoyl peroxide

X-ray and electron paramagnetic resonance structural investigation of oxygen discrimination during the collapse of methyl-benzoyloxy radical pairs in crystalline acetyl benzoyl peroxide

Chemically induced nuclear polarization in the thermal decomposition of benzoyl and acetylbenzoyl peroxides in the presence of iodides

1. A similarity of the observed effects of chemical polarization of nuclei and the composition of the products was detected in reactions of thermal decomposition of benzoyl peroxide in the presence of methyl iodide and that of acetylbenzoyl peroxide. 2. The experimental and theoretical data are evidence of complex formation of iodides with the benzene ring of the peroxide and an acceleration of decomposition on account of this benzoyl radical. 3. A secondary radical pair is formed from the iodide-benzene ring complex at a rate k1 ≅ 1010 sec−1.

13C CIDNP effects in the decomposition products of acetylbenzoyl peroxide

Abstract13C CIDNP effects in the decomposition of acetylbenzoyl peroxide in cyclohexanone are described. A comparison between our data, and those on the 1H CIDNP effects and the 13C CIDNP observed in the decomposition of ABP in C2Cl41 leads to definite conclusions on the signs of the HFI constants of the benzoyl radical and to an identification of the separate products of the radical‐induced reactions with the solvent.

Solvent steric effects. VII. Lattice control of free radicals from the photolysis of crystalline acetyl benzoyl peroxide

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolvent steric effects. VII. Lattice control of free radicals from the photolysis of crystalline acetyl benzoyl peroxideNathan J. Karch and J. Michael McBrideCite this: J. Am. Chem. Soc. 1972, 94, 14, 5092–5093Publication Date (Print):July 1, 1972Publication History Published online1 May 2002Published inissue 1 July 1972https://doi.org/10.1021/ja00769a057RIGHTS & PERMISSIONSArticle Views42Altmetric-Citations4LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (283 KB) Get e-Alerts Get e-Alerts

Chemical polarization of the nuclei in the reaction of a stable nitroxyl radical with acetylbenzoyl peroxide

Chemical polarization of the nuclei in the reaction of a stable nitroxyl radical with acetylbenzoyl peroxide

Study on Scrambling in Decomposition of Labeled Acetyl Benzoyl Peroxide

Study on Scrambling in Decomposition of Labeled Acetyl Benzoyl Peroxide

Chemical polarization of nuclei. PMR spectra of decomposition products of dimethyl peroxydiphthalate

AbstractChemical polarization of protons was observed in methyl benzoate formed during the thermal decomposition of dimethyl ester of peroxydiphthalic acid. The polarization pattern of methyl benzoate aromatic protons was very different in this case from that observed during the thermal decomposition of acetyl benzoyl peroxide. The unpolarized products formed from the methoxy radical, CH2O and CH3OH, were found in the mixture of decomposition products of this peroxide and were identified by means of PMR spectroscopy.