256
R. Tesser et al.
The use of a heterogeneous catalyst is more desirable: apart from the beneficial
recovery of the catalyst at the end of process, a suppression of side reactions could
be feasible, accounting for the lack of free acidity in the reaction environment.
Many different catalytic systems for epoxidation with hydrogen peroxide have
been proposed in the literature [154]. Among them, titanium silicalite (TS-1) has
been praised as a milestone for the oxidation of olefins with hydrogen peroxide
[208]. However, this catalyst is barely active with larger unsaturated molecules like
oils and methyl esters, due to the diameter of the small pores (5.6 × 4.7 Å) of TS-1.
Broad work was done to incorporate Ti(IV) in large molecular sieves pores, leading
to materials such as Ti-MCM-41 and Ti-MCM-48 [180]. Recently, some niobium–
silica and niobium–alumina-based solids have been described in the literature as
active catalysts for the epoxidation reaction [212, 215]. A strict correlation between
the surface distribution of active sites and synthesis methods has been reported.
Among free-transition metals catalyst, γ-alumina-based materials are of interest. It
has been shown that this oxide has been able to activate hydrogen peroxide for the
oxidation, through the formation of a peroxide site [213].
Organic hydroperoxides, such as tert-butyl hydroperoxides (TBHP) or cumyl
hydroperoxides (CHP), have been reported as alternative oxidizing agents. However, they are successfully applied in few oxidations of oils, and always in the presence of homogenous catalysts based on vanadium, titanium or molybdenum. This
compromises the application on a larger scale.
The chemoenzymatic approach gained increasing interest in an alternative to the
chemical one, because the use of lipases allows obtaining a very high stereoselectivity,
with suppression of side reactions (Rios et al. 2011). The reaction mixture, in the
chemoenzymatic epoxidation, usually consists in three phases system which involves
an aqueous phase containing hydrogen peroxide, an organic phase containing solvent
and oil, and a solid phase corresponding to lipase (Candida antartica Lipase B, CALB)
immobilized on resin or silica (Novozym 435
® or CALB-silica). The epoxidation
proceeds in two steps: the first consists of the hydrolysis by the reaction of triglyceride
with H 2 O 2 in presence of lipase; the second is the self-epoxidation with the EVOs
formation.
Although high selectivity, this route is not feasible on the industrial scale, due
to various drawbacks such as the large use of solvent, high cost of lipase and rapid
deactivation of the latter [48].
References
1. Adegoke GO, Iwahashi H, Komatsu Y, Obuchi K, Iwahashi Y (2000) Inhibition of food
spoilage yeasts and aflatoxigenic moulds by monoterpenes of the spice Aframomum danielli.
Flavor Fragr J 15:147–150. https://doi.org/10.1002/1099-1026(200005/06)15:3147::AIDFFJ8833.0.CO;2-0
2. Adewuyi A (2014) Synthesis and surface-active property of diethanolamide and epoxidised
diethanolamide surfactant from the seed oil of Baphia nitida. Arab J Chem 12: 1545–1551.
https://doi.org/10.1016/j.arabjc.2014.10.021
R. Tesser et al.
The use of a heterogeneous catalyst is more desirable: apart from the beneficial
recovery of the catalyst at the end of process, a suppression of side reactions could
be feasible, accounting for the lack of free acidity in the reaction environment.
Many different catalytic systems for epoxidation with hydrogen peroxide have
been proposed in the literature [154]. Among them, titanium silicalite (TS-1) has
been praised as a milestone for the oxidation of olefins with hydrogen peroxide
[208]. However, this catalyst is barely active with larger unsaturated molecules like
oils and methyl esters, due to the diameter of the small pores (5.6 × 4.7 Å) of TS-1.
Broad work was done to incorporate Ti(IV) in large molecular sieves pores, leading
to materials such as Ti-MCM-41 and Ti-MCM-48 [180]. Recently, some niobium–
silica and niobium–alumina-based solids have been described in the literature as
active catalysts for the epoxidation reaction [212, 215]. A strict correlation between
the surface distribution of active sites and synthesis methods has been reported.
Among free-transition metals catalyst, γ-alumina-based materials are of interest. It
has been shown that this oxide has been able to activate hydrogen peroxide for the
oxidation, through the formation of a peroxide site [213].
Organic hydroperoxides, such as tert-butyl hydroperoxides (TBHP) or cumyl
hydroperoxides (CHP), have been reported as alternative oxidizing agents. However, they are successfully applied in few oxidations of oils, and always in the presence of homogenous catalysts based on vanadium, titanium or molybdenum. This
compromises the application on a larger scale.
The chemoenzymatic approach gained increasing interest in an alternative to the
chemical one, because the use of lipases allows obtaining a very high stereoselectivity,
with suppression of side reactions (Rios et al. 2011). The reaction mixture, in the
chemoenzymatic epoxidation, usually consists in three phases system which involves
an aqueous phase containing hydrogen peroxide, an organic phase containing solvent
and oil, and a solid phase corresponding to lipase (Candida antartica Lipase B, CALB)
immobilized on resin or silica (Novozym 435
® or CALB-silica). The epoxidation
proceeds in two steps: the first consists of the hydrolysis by the reaction of triglyceride
with H 2 O 2 in presence of lipase; the second is the self-epoxidation with the EVOs
formation.
Although high selectivity, this route is not feasible on the industrial scale, due
to various drawbacks such as the large use of solvent, high cost of lipase and rapid
deactivation of the latter [48].
References
1. Adegoke GO, Iwahashi H, Komatsu Y, Obuchi K, Iwahashi Y (2000) Inhibition of food
spoilage yeasts and aflatoxigenic moulds by monoterpenes of the spice Aframomum danielli.
Flavor Fragr J 15:147–150. https://doi.org/10.1002/1099-1026(200005/06)15:3147::AIDFFJ8833.0.CO;2-0
2. Adewuyi A (2014) Synthesis and surface-active property of diethanolamide and epoxidised
diethanolamide surfactant from the seed oil of Baphia nitida. Arab J Chem 12: 1545–1551.
https://doi.org/10.1016/j.arabjc.2014.10.021