Catalytic Mono-Functionalization of Triyacylglycerols

Selective introduction of one functional group in a triacylglycerol molecule is an important target for the utilization of plant oils for polymer applications, e.g. paints and varnishes.
A reported two-step procedure for the introduction of acryl groups in triacylglycerols consists of the epoxidation of C=C-bonds and the subsequent ring-opening of the epoxide with acrylic acid. Thus, a mono-acrylated triacylglycerol can be obtained by mono-epoxidation in the first step. This was carried out by the classic Prileshajev-epoxidation with peracetic acid and by the more selective chemo-enzymatic epoxidation.
A (statistically) mono-epoxidized oil can also be made by the catalytic randomization of a commercial fully-epoxidized soybean oil with an adequate amount of any other triacylglycerol. The interesterification is favorably catalyzed by a lipase, because the epoxide-ring might react under standard conditions with a strong base as catalyst.
An acryl group can be directly introduced in a triacylglycerol by lipase-catalyzed interesterification. The most straightforward way would be the reaction of a triacryl glycerol with an adequate amount of a plant oil. However, triacryl glycerol is not a commercial commodity; therefore we used trimethylol propane (TMP) triacrylate for the same purpose. Starting with butyl acrylate a product of slightly different composition was obtained.
Both two-step and one-step reactions were carried out with various unsaturated plant oils like linseed oil, soybean oil and hemp oil.
Selectivities and product characteristics will be shown; safety concerns and different problems in downstream-processing will be discussed.