Short Communication Oxidations by the system ‘hydrogen peroxide–[Mn 2 L 2 O 3 ] 2+ (L = 1,4,7-trimethyl-1,4,7-triazacyclononane)–carboxylic acid’ Part 13. Epoxidation of methyl oleate in acetonitrile solution [1] Dalmo Mandelli a, ⁎, Yuriy N. Kozlov b , Wagner A. Carvalho a , Georgiy B. Shul'pin b, ⁎⁎ a Center of Natural and Human Sciences, Federal University of ABC (UFABC), Santa Adélia Street, 166, Bangu, Santo André, SP, 09210‐170, Brazil b Semenov Institute of Chemical Physics, Russian Academy of Sciences, Ulitsa Kosygina, dom 4, Moscow 119991, Russia abstract article info Article history: Received 22 February 2012 Received in revised form 3 April 2012 Accepted 12 April 2012 Available online 25 April 2012 Keywords: Biodiesel Epoxidation Fatty acid methyl esters (FAMEs) Homogeneous catalysis Manganese complexes Renewables Methyl oleate can be efficiently (yield and selectivity attain 100%, turnover number is up to 2000) epoxidized with hydrogen peroxide in acetonitrile solution at 25 °C using the combination “[Mn 2 L 2 O 3 ](PF 6 ) 2 (L = 1,4,7- trimethyl-1,4,7-triazacyclononane)/oxalic acid” as a catalyst. Kinetic features of the reaction were studied and the conclusion has been made that high-valent oxo-manganese rather than hydroxyl radicals is a crucial oxidizing species in this process. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Modified vegetable oils play an important role in the modern chemical industry because they can be easily obtained from renew- able resources [2–4]. Unsaturated vegetable oils (for example, soy- bean oil contains 23% oleic acid) can be epoxidized [5–7] to various products that are used as building blocks for the preparation of valu- able chemical intermediates: reactive diluents for paints and interme- diates in the production of polyurethane-polyols. Epoxides of fatty acid methyl esters (FAMEs) play an important role as intermediates in the production of lubricants, plasticizers in polymers and stabi- lizers in chlorine-containing resins, and they find applications in the manufacture of cosmetics, wood impregnation, pharmaceuticals, and bio-fuel additives. Methyl oleate [methyl (Z)-octadec-9-enoate; a component of the Queen Retinue Pheromone [8]; compound 2 in Scheme 1] and methyl epoxystearate (the epoxide obtained from methyl oleate epoxidation; compound 3 in Scheme 1) are among such practically valuable substances. Catalytic oxygenation of methyl oleate with hydrogen peroxide is one of the promising routes to the important epoxide. The dinuclear manganese(IV) complex [LMn(O) 3 MnL](PF 6 ) 2 (catalyst 1; L is 1,4,7-trimethyl-1,4,7-triazacyclononane, TMTACN; see Scheme 1) as well as some similar compounds [9–11] are known to catalyze oxida- tions of olefins and phenols. Earlier some of us discovered that compound 1 catalyzes the oxidation of various organic compounds by hydrogen peroxide much more efficiently if a small amount of a carboxylic acid is added to the reaction solution [1,12–28]. The ‘1/carboxylic acid/H 2 O 2 ’ system in acetonitrile solution very efficiently epoxidizes olefins [14,16–18,24], transforms alcohols into ketones (aldehydes) [14,19,23], sulfides into sulfoxides [14] and causes the degradation of dye Rhoda- mine 6G [22]. The reaction with olefins gave rise to the products of dihydroxylation [16] in addition to the corresponding epoxides. The combination ‘1/carboxylic acid/H 2 O 2 ’ oxidizes also inert alkanes in ace- tonitrile [12–16,20,21] to afford primarily the corresponding alkyl hydroperoxides which are transformed further into the more stable ke- tones (aldehydes) and alcohols. Olefins [17], alcohols [19] and alkanes [17] were oxidized also in the absence of acetonitrile. Olefins and al- kanes can be oxidized by tert-butyl hydroperoxide [14] or peroxyacetic acid [12,25] using complex 1 as a catalyst. The reaction with tert-butyl hydroperoxide is significantly accelerated in the presence of a small Catalysis Communications 26 (2012) 93–97 ⁎ Corresponding author. ⁎⁎ Corresponding author. Fax: + 7 499 1376130. E-mail addresses: dalmo.mandelli@uol.com.br (D. Mandelli), Shulpin@chph.ras.ru (G.B. Shul'pin). 1566-7367/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.catcom.2012.04.019 Contents lists available at SciVerse ScienceDirect Catalysis Communications journal homepage: www.elsevier.com/locate/catcom