Cu single-atom catalysts (SACs) supported on CeO 2 −TiO 2 were prepared by a sol−gel method and tested for CO oxidation between 120 and 350 °C. Operando and in situ spectroscopic methods including diffuse reflectance infrared Fourier transform (DRIFT), electron paramagnetic resonance (EPR), and near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) combined with other basic characterizations were applied to identify active sites and to derive reliable structure−reactivity relationships. Rising the Cu content from 0.06 to 0.86 wt % resulted in a significant decrease of the Cu-mass normalized CO 2 formation rate from 690 to 310 μmol CO 2 •g Cu −1 •s −1 at 250 °C, which was attributed to the formation of the less active CuO x species. The catalysts showed high stability during time on stream for more than 1000 min with negligible agglomeration of Cu single sites. Spectroscopic results revealed that active sites are single Cu ions on the surface of highly dispersed ceria particles, shuttling between −Cu 2+ −O−Ce 4+ − and −Cu + −□−Ce 3+ − by supplying active oxygen for oxidation of CO to CO 2 . The highest concentrations of Cu single sites and O vacancies associated with Ce 3+ species correlated with the highest CO oxidation activity.

The effect of different AlR3 activators (R=methyl, ethyl, isobutyl, n‐octyl) has been studied in comparison to modified methylaluminoxane (MMAO) by operando EPR as well as by in situ UV‐vis, ATR‐IR and XANES/EXAFS spectroscopy during oligomerization of ethylene at 20 bar and 40 °C with a homogeneous Cr complex catalyst formed in situ upon mixing a Cr(acac)3 precursor, a Ph2PN(iPr)PPh2 ligand (PNP) and the activator. Coordination of PNP to Cr(acac)3 is initiated only in the presence of an activator. Highest 1‐octene productivity (detected during operando EPR measurements) was obtained with MMAO which promotes bidentate coordination of the ligand to form an active (PNP)CrII(CH3)2 chelate complex. Rising bulkiness of R in AlR3 leads to only monodentate coordination of PNP to the Cr center by one P atom and increasing reduction to CrI to a maximum extend of around 30 % for AlOct3. This lowers the catalytic performance, which is mainly governed by the mode of PNP coordination rather than by the CrI content.

Commercial polyether polyols are usually obtained by the ring-opening polymerization of epoxides or tetrahydrofuran. 2-Methyl-tetrahydrofuran (2-MeTHF) could be an alternative bio-based building block for the synthesis of these polyols. Although 2-MeTHF cannot be polymerized, we did achieve the copolymerization of 2-MeTHF with propylene oxide (PO) using Lewis and Brønsted acids as catalysts and water or diols as initiators. The resulting polyether polyols have a molecular weight range, which allows their use as components for adhesives. The molar content of 2-MeTHF in the oligomers can be up to 48%. A 1:1 copolymer of 2-MeTHF and PO is produced when stoichiometric amounts of BF3·OEt2 are used. Here, the monomeric units in the chains alternate, but also cyclic or other nondiol products are formed that are detrimental to its further use in adhesives. Linear dihydroxyl-terminated polyether chains were formed when the heteropolyacid H3PW12O40·24H2O was used as a catalyst and a diol as an initiator. The formation of cyclic products can be drastically reduced when the accumulation of propylene oxide during the reaction is avoided. 1H NMR experiments indicate that the step of 2-MeTHF incorporation is the alkylation of 2-MeTHF by protonated PO. It was shown that the 2-MeTHF/PO copolymer had increased tensile strength compared to polypropylene glycol in a two-component adhesive formulation.

The iridium catalyzed transfer vinylation of bio‐based polyols and of other alcohols and phenols with interesting structural motifs was accomplished with vinyl acetate in 2‐MeTHF as a green solvent. The optimized synthetic procedure has as main advantages the use of catalytic instead of stoichiometric amounts of base and high selectivities towards the formation of bis‐vinyl ethers as a result of the suppression of the acetal formation reaction that typically occurs in the vinylation of diols. In addition, the thermodynamically preferred transesterification reaction leading to the acetate esters and bis‐esters was completely suppressed. DFT calculations revealed an iridium‐acetate complex as the active catalytic species and they disclosed the importance of the carbonyl group of vinyl acetate for the formation of a six‐membered cyclic intermediate.

The front cover picture depicts bio‐based bis‐vinyl ether structures which were synthesized through a catalytic transfer vinylation reaction, where a cationic iridium complex was used as the catalyst, sodium acetate as the base, vinyl acetate as the vinylating agent, and 2‐MeTHF as a green solvent. Many of the herein described (bis)‐vinyl ethers are reported for the first time and bear high potential as an integral part in adhesives, coatings, or UV‐inks. Details can be found in the research article by de Vries and co‐workers (B. Spiegelberg, H. Jiao, R. Grauke, C. Kubis, A. Spannenberg, A. Brandt, A. Taden, H. Beck, S. Tin, J. G. de Vries, Adv. Synth. Catal. 2022, 364, 1251–1263; DOI: 10.1002/adsc.202101348).