New zinc guanidine complexes with N,O donor functionalities were prepared, characterized by X-Ray crystallography, and examined for their catalytic activity in the solvent-free ring-opening polymerization (ROP) of technical-grade rac-lactide at 150 °C. All complexes showed a high activity. The fastest complex [ZnCl (DMEGasme)] (C1) produced colorless poly(lactide) (PLA) after 90 min with a conversion of 52 % and high molar masses (M =69 100, polydispersity=1.4). The complexes were tested with different monomer-to-initiator ratios to determine the rate constant k . Furthermore, a polymerization with the most active complex C1 was monitored by in situ Raman spectroscopy. Overall, conversion of up to 90 % can be obtained. End-group analysis was performed to clarify the mechanism. All four complexes combine robustness against impurities in the lactide with high polymerization rates, and they represent the fastest robust lactide ROP catalysts to date, opening new avenues to a sustainable ROP catalyst family for industrial use.

The Guerbet reaction from two alcohols to a long-chain alcohol and water requires a redox catalyst and a strong base in homogeneous liquid systems. Especially, the reaction from ethanol to n-butanol is a challenging example of the reaction that suffers from low yields and selectivities in comparison with reactions of higher alcohols. The most important side reactions are the polymerization of acetaldehyde to C 6 + -components and the saponification of ethyl acetate under consumption of the base. This work pursues the systematic kinetic investigation of the Guerbet reaction network by experiments with isolated subsystems of the network. In-situ-infrared spectroscopy is applied to determine time-resolved concentration profiles. Adapted kinetic models of the single steps are integrated into a microkinetic model of the whole network. The simulation of the reaction network reveals dependencies between temperature, hydrogen pressure, initial concentrations and the yield and selectivity of n-butanol. Finally, it is shown that Ru-MACHO does not lead to high yields in the reaction, because the dehydrogenation to ethyl acetate exhibits a too low activation barrier.

A detailed overview for homogeneously catalyzed strategies and synthesis pathways using a combination of CO2, CO, and H2 as active building blocks to selectively obtain C1–C4 alcohols is presented. Conceptual strategies applying homologation, carbonylation, hydrocarboxylation, and hydrogenation reactions will be discussed, finally combining the individual reaction approaches towards potential new pathways to the envisaged alcohol products. Also, tailored reactor concepts with adapted recycling/separation methods for the molecular catalyst systems will be shown and discussed.

The kinetics of the methylation of triethylamine (NEt) with dimethyl carbonate (DMC) in methanol have been investigated by means of in situ ATR-IR-spectroscopy. The data show an autocatalytic influence of the ionic product on reaction kinetics. A bend in the reaction rate progress indicates a sudden change from solvated ions to a microstructured biphasic system, which is reflected in the dependence of the reaction rate constant on the product concentration and the Hildebrand parameter.