Lipase-mediated Epoxidation of the Cyclic Monoterpene Limonene to Limonene Oxide and Limonene Dioxide

Abstract

Limonene is an industrially interesting monoterpene that accumulates in bulk quantities as byproduct of the fruit juice industry. The corresponding epoxides are versatile synthetic intermediates and additives for the chemical industry. Due to a number of disadvantages of classical chemical epoxidation including serious safety issues and unwanted side-reactions, we here used a mild lipasecatalyzed chemo-enzymatic epoxidation system, with either free or different immobilized forms of Candida antarctica lipase B. Full limonene conversion (> 98 %) was easily achieved at 40 • C within less than 24 h. The enzymatic activities in the formation of limonene monoxide significantly varied from either 1 -3.4 U/mg biocatalyst at r. t. or from 1.7 -4.9 U/mg biocatalyst at 40 • C. For the first time we showed that it is possible to generate high amounts of limonene dioxide (∼ 30 % with CalB on carrier 350 at 40 • C) using this mild lipase-mediated epoxidation method. Enzyme activities and limonene dioxide yields strongly depend on the nature of the selected enzyme carrier, the immobilization method and the reaction temperature.

Produktion von Peroxyoktansäure mittels immobilisierter CalB: Realisierbarkeitsstudie im einphasigen Stoffsystem mit graduellem Wasserstoffperoxid‐Dosing

“…Unfortunately, in harsh environments, terpenes and their epoxides are rapidly rearranged to unwanted side-products [49]. With an excess of hydrogen peroxide, the lipase-mediated epoxidation also tends to produce by-products, which have been reported for limonene [50] and for α-pinene [35,48]. Additionally, acid-catalyzed rearrangement was shown for pinenes [40].…”

“…The lipase-mediated epoxidation of terpenes also tends to form by-products [31,35,50,53]. This is taken into account by the following second order side reaction (S)…”

Chemo-enzymatic routes towards the synthesis of bio-based monomers and polymers

“…Limonene di-carbonate (53) derived from waste feedstock is a versatile synthetic intermediate and an important monomer in the synthesis of bio-based PU. Both mono and di-epoxide (52) of limonene can be accessed through lipase-catalysed epoxidation via in-situ formation of peroxy acids [111] followed by carbonation by CO 2 . [112] The corresponding bicyclic carbonate has been used in the synthesis of NIPU thermoplastics with cadaverine as the amine partner.…”

Biocatalytic Synthesis of a Diketobornane as a Building Block for Bifunctional Camphor Derivatives

“…The introduction of additional functional groups into terpenes is an important issue in catalysis research 7. The most widely used method is the modification of double bonds 8. More challenging, however, is the modification of non‐activated CH bonds.…”