Efficient ruthenium-catalysed oxidative cleavage of methyl oleate with hydrogen peroxide as oxidant

Abstract

The oxidative cleavage of alkenes leads to the formation of carboxylic acids. One of the few technical processes using this reaction is the production of azelaic acid via the ozonolysis of oleic acid. Because of the need for stoichiometric amounts of the expensive oxidant ozone, together with safety hazards, there is still a requirement for a catalytic process using a cheap and environmentally friendly oxidant. In the present work, the oxidative cleavage of methyl oleate by hydrogen peroxide was catalysed by an easily available ruthenium precursor with dipicolinic acid as ligand. The systematic optimisation of the reaction led to the formation of azelaic acid monomethyl ester in high yields amounting to 86%. The investigation of the reaction pathway showed that the reaction proceeds via a tandem reaction of epoxidation and hydrolysis of the epoxide and oxidative cleavage of the vic-diol.

Optimization of A Two-Step Method to Synthesize Azelaic Acid from Oleic Acid

“…The major factors that can affect the oxidative cleavage process are the substrate molar ratio, catalyst concentration, the mass of sodium hypochlorite, temperature, reaction time, and stirring speed 7,9 . Three factors are then selected as the independent variables; they are catalyst concentration (w/wOA), substrate molar ratio (H 2 O 2 /OA), and temperature ( o C).…”

“…The useable catalysts among others manganese (Mn), tungstic acid (H 2 WO 4 ) and methyltrioxorhenium (MeReO 3 ) 15 . The tungstic acid is a suitable catalyst for oxidizing agent and more environmentally friendly than tungstate phosphor acid, so the use of tungstic acid as a catalyst needs to be further studied 9,15 .…”

“…Oxidants such as sodium periodate, peroxomonosulfate, para-acetate acid and tertbutyl hydroperoxide are often used in this reaction because they are strong oxidizing reagents even without the addition of transition metals but produce unsustainable waste 3,9 . Hydrogen peroxide (H 2 O 2 ) is an attractive alternative oxidant because it does not produce waste at the end of the reaction but almost requires transition metal to be able to oxidize substrates with maximum 10,11 .…”

Computer-aided modelling template: Concept and application

“…The unsaturated fatty acid (UFA) is mixed with t-BuOH. As t-BuOn is a solvent which can dissolve both polar and non-polar compounds, the resulting mixture is a single phase system (Behr et al, 2013) In the following template use workflow the choices made by user are described.…”

The mission of addition and fission – catalytic functionalization of oleochemicals

“…In a two‐step procedure, the isolated methyl 9,10‐epoxy stearate can be hydrolyzed in a solvent mixture comprising of t BuOH:H 2 O in a 3:1 ratio at a p H adjusted to 2.4 with sulfuric acid. Very high yields of 97% for methyl 9,10‐dihydroxy stearate can be obtained at 80°C and a reaction time of 4 h .…”