Photooxidation of benzil groups in the presence of hindered amine stabilizers in the polystyrene film

Kósa, Csaba; Mosnáček, Jaroslav; Lukáč, Ivan; Hrdlovič, Pavol; Chmela, Štefan; Habicher, Wolf D.

doi:10.1002/app.23212

Cited by 5 publications

(1 citation statement)

References 25 publications

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“…Therefore, both fluorescence and phosphorescence from BZ are dependent on external constraints imposed by the environment. Based upon the fact that the absorption maxima of BZ in toluene [ 23 ] and in a PS matrix [ 24 ] are both at 390 nm, we infer that the BZ ground state conformations are skewed to the same degree in the two media. The phosphorescence maximum of BZ in various solvents at 77 K (solids) is at ca.…”

Section: Photochemistry Of Benzil In Solution In the Absence Of Molecular Oxygenmentioning

confidence: 99%

Benzil Photoperoxidations in Polymer Films and Crosslinking by the Resultant Benzoyl Peroxides in Polystyrene and Other Polymers

et al. 2021

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Benzil (BZ) can be converted almost quantitatively to benzoyl peroxide (BP) in aerated polymer films upon irradiation at >400 nm (i.e., the long-wavelength edge of the n→π* absorption band of BZ, where BP does not absorb). Here, we summarize results for the photoperoxidation of BZ structures with molecular oxygen, principally in glassy polymer matrices. Some of the polymers are doped directly with BZ or its derivatives, and others, contain covalently attached BZ pendant groups from which BP groups are derived. While the decomposition of low-molecular-weight BP doped into polymer films (such as those of polystyrene (PS)) results in a net decrease in polymer molecular weight, thermal decomposition of pendant BP groups is an efficient method for chain crosslinking. Crosslinking of PS films doped with a molecule containing two covalently linked BZ or BP groups proceeds in a similar fashion. Free radicals from the covalently attached BP allow grafting of new monomers, as well. Additionally, the use of radiation filtered through masks has been used to create patterns of polymers on solid surfaces. Crosslinking of photodegradable poly(phenyl vinyl ketone) with BP structures obtained by photoperoxidation of BZ structures for the preparation of photodegradable polymer networks is described as well. In sum, the use of BZ and BP and their derivatives offers simple and convenient routes for modifying polymer chains and, especially, for crosslinking them. Specific applications of each use and process are provided. Although applications with PS are featured here, the methodologies described are amenable to a wide variety of other polymers.

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Section: Photochemistry Of Benzil In Solution In the Absence Of Molecular Oxygenmentioning

confidence: 99%

Benzil Photoperoxidations in Polymer Films and Crosslinking by the Resultant Benzoyl Peroxides in Polystyrene and Other Polymers

et al. 2021

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One‐Pot Synthesis of p‐Amino‐Substituted Unsymmetrical Benzils and Benzil Derivatives

et al. 2017

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An efficient iodine/copper(II) oxide co‐promoted direct oxidative coupling of anilines and methyl aryl ketones has been developed for the synthesis of p‐amino‐substituted unsymmetrical benzils and their iodo‐substituted derivatives. The chemoselectivity of the reactions can be easily controlled by adjusting the amount of iodine. This method exhibits good functional group tolerance for various substituents on the aromatic rings of the methyl aryl ketones. A possible mechanism for this reaction has been proposed based on control experiments. A couple of representative quinoxalines were synthesized from the benzil products in order to demonstrate the utility of this approach.magnified image

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Pd/Cu-catalyzed oxidation of alkynes into 1,2-diketones using DMSO as the oxidant

Gao

Yang

et al. 2012

Tetrahedron

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Photooxidation of benzil groups in the presence of hindered amine stabilizers in the polystyrene film

Cited by 5 publications

References 25 publications

Benzil Photoperoxidations in Polymer Films and Crosslinking by the Resultant Benzoyl Peroxides in Polystyrene and Other Polymers

Benzil Photoperoxidations in Polymer Films and Crosslinking by the Resultant Benzoyl Peroxides in Polystyrene and Other Polymers

One‐Pot Synthesis of p‐Amino‐Substituted Unsymmetrical Benzils and Benzil Derivatives

Pd/Cu-catalyzed oxidation of alkynes into 1,2-diketones using DMSO as the oxidant

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