Mark Rüsch gen. Klaas

Polymers and surfactants on the basis of renewable resources

A new strategy for the preparation of different polymers and special surfactants was developed. First, unsaturated fatty acid methyl esters obtained from plant oils were converted to terminally unsaturated esters and alpha-olefins by metathesis with ethylene using heterogeneous rhenium or homogeneous ruthenium catalysts. These esters were directly copolymerized with ethylene by an insertion-type palladium-catalyzed polymerization to functionalized polyolefins. Polyesters were synthesized by metathetical dimerization of omega-unsaturated esters and subsequent polycondensation of the produced internally unsaturated dicarboxylic esters or by acidic transesterification with petrochemical diols and additional acyclic diene metathesis polymerization. Omega-epoxy fatty acid methyl esters, achieved by a new method of chemo-enzymatic epoxidation, were converted into polyethers with comb-structure catalyzed by aluminoxanes on the one hand and into sugar surfactants by nucleophilic ring-opening with amino carbohydrates on the other hand.

Chemo-enzymatic epoxidation of unsaturated carboxylic acids

Abstract Unsaturated carboxylic acids are converted to percarboxylic acids catalyzed by an immobilized lipase from Candida antarctica (Novozym 435 R ). These unsaturated percarboxylic acids are only intermediates and epoxidize themselves in good yields and almost without consecutive reactions. The mechanism of the oxygen-transfer is found to be predominantly intermolecular and the formation of the percarboxylic acids proceeds via two different catalytic reactions. The lipase is surprisingly stable under the reaction conditions; it is recovered and reused fifteen times to produce epoxy-stearic acid on a multi-gram scale.

Lipase-catalyzed preparation of peroxy acids and their use for epoxidation☆

Abstract The lipase-catalyzed reactions of carboxylic acids and carboxylic acid esters with hydrogen peroxide are used to generate various peroxy acids at room temperature and without mineral acids. Whereas Novozym 435 R will only be able to catalyze the conversion of free unbranched carboxylic acids to peroxy acids, α-methylsubstituted carboxylic acid ethylesters can be converted to peroxy acids by perhydrolysis using the same enzyme. These peroxy acids are used in-situ for the epoxidation of unsaturated compounds and thus a new versatile epoxidation method for organic synthesis is proposed.

Biocatalytic peroxy acid formation for disinfection

Novel peroxy acids were prepared by two methods using Novozyme® 435 as a catalyst; either free carboxylic acids were converted with hydrogen peroxide or carboxylic acid esters were perhydrolyzed by hydrogen peroxide. Afterwards, these peroxy acids (as solutions in their respective ethyl or methyl esters) were tested for their sporicidal activity towards spores of Bacillus subtilis. The sporicidal activity of peroxy acetic acid made by biocatalytic perhydrolysis was found to be the same as one of commercial peroxy acetic acid. Peroxy methoxy acetic acid, peroxy propionic acid, peroxy phenyl acetic acid, and peroxy citric acid showed comparable or slightly lower activities. Sporicidal activities do not directly relate to oxidative power. Under the conditions applied, long-chain peroxy acids like peroxy dodecanoic acid (perlauric acid) and peroxy octadecanoic acid (perstearic acid) were unsuitable as disinfectants due to their very limited solubility at pH 7.

Lipase-catalyzed conversions of trimethylsilyl ethers : deprotection, acetylation, epoxidation and one-pot-multi-step reactions

Abstract Unsaturated trimethylsilyl ethers are converted by lipase-catalyzed hydrolysis of ethyl acetate directly to alkenol acetates; the hydrolysis of diethyl carbonate yields unstable carbonic acid monoethylester, which deprotects trimethylsilyl ethers under mild conditions and without remaining acid. By the analogous lipase-catalyzed perhydrolysis of these esters with hydrogen peroxide, epoxyalkanol acetates and epoxyalkanols are obtained in one-pot reactions with selectivities of 90–97%. Using longer chain peroxy fatty acids, generated in-situ by lipase-catalyzed reaction of fatty acid and hydrogen peroxide, trimethylsilyl ethers are selectively (83–95%) epoxidized without removal of the protecting trimethylsilyl group.

An efficient method for lipase-catalysed preparation of acrylic and methacrylic acid esters

Novozym 435 — a commercially available immobilized lipase from Candida antarctica — shows an activity for the transesterification using acrylic or methacrylic methylester as solvent and as acylating agent superior to all other enzymes tested. This transesterification is very fast compared to other enzyme-catalysed reactions (1.5 h). Novel acrylic and methacrylic esters from unsaturated fatty alcohols can be prepared this way in yields of 65 to 94 % and under mild conditions (30 °C, atmospheric pressure).

Synthesis of dicarboxylic acids by transition-metal catalyzed oxidative cleavage of terminal-unsaturated fatty acids

9-Decenoic- and 13-tetradecenoic methylesters, obtained by Re-catalysed metathesis of natural C18- and C22-fatty esters with ethylene as well as the industrially produced 10-undecenoic methylester were used as starting materials for the preparation of dicarboxylic esters. Two different reaction routes were applied. Ketonisation of the terminal unsaturated fatty acid esters by Wacker-oxidation using PdCl2/CuCl or RhCl3/FeCl3 as catalysts led to methyl keto-fatty acid esters, which were oxidatively cleaved by Mn-catalysed oxidation with air at 115 °C to mixtures of C8-/C9-, C9-/C10- and C12-/C13-dicarboxylic monomethylesters with conversion rates and selectivities of 90%.

Formation of vicinal diols by Re2O7-catalysed hydroxylation of alkenes with hydrogen peroxide

Alkenes are hydroxylated to vicinal diols by H2O2 in 1,4-dioxane as solvent and using 1 mol% Re2O7 as catalyst, which can be easily separated from the products and recycled for several runs.