Home >> Redox Report, Volume 12, Number 6

Visible-light promoted degradation of the commercial antioxidants butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT): a kinetic study

Authors: Criado, Susana1; Allevi, Carolina1; Ceballos, Claudio2; García, Norman1

Source: Redox Report, Volume 12, Number 6, December 2007 , pp. 282-288(7)

Publisher: Maney Publishing

Buy & download fulltext article:

OR

Price: $48.00 plus tax (Refund Policy)

Abstract:

Visible-light photo-irradiation of the commercial phenolic antioxidants (PhAs) butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT), in the presence of vitamin B2 (riboflavin, Rf), in methanolic solutions and under aerobic conditions, results in the photo-oxidation of the PhAs. The synthetic dye photosensitiser Rose Bengal was also employed for auxiliary experiments. With concentrations of riboflavin and PhAs of ca. 0.02 mM and < 1 mM, respectively, the excited triplet state of the vitamin (3Rf*) is quenched by BHT in a competitive fashion with dissolved ground state triplet oxygen. From the quenching of 3Rf*, the semireduced form of the pigment is generated through an electron transfer process from BHT, with the subsequent production of superoxide anion radical (O2•?) by reaction with dissolved molecular oxygen. In parallel, the species singlet molecular oxygen, O2(1?g), is also generated. Both reactive oxygen species produce the photodegradation of BHT. In the case of BHA, the lack of any effect exerted by superoxide dismutase drives out a significant participation of a O2•?-mediated mechanism. BHA mainly interacts with O2(1?g) and exhibits a desirable property as an antioxidant – a relatively high capacity for O2(1?g) de-activation and a low photodegradation efficiency by the oxidative species. Electrochemical determinations support the proposed photodegradative mechanism.

Keywords: PHOTO-OXIDATION; BUTYLATED HYDROXYANISOLE; BUTYLATED HYDROXYTOLUENE; PHENOLIC ANTIOXIDANTS

Document Type: Research Article

DOI: http://dx.doi.org/10.1179/135100007X239252

Affiliations: 1: Departamento de Química, Universidad Nacional de Río Cuarto, Río Cuarto, Argentina 2: Facultad de Ingeniería, Universidad Nacional de Río Cuarto, Río Cuarto, Argentina

Publication date: 2007-12-01

Related content
Marked list

Tools

Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content

Text size:

A | A | A | A
^ Back to top
Share this item with others: These icons link to social bookmarking sites where readers can share and discover new web pages. print icon Print this page