A typical feature that the LOHC technology shares with other types of chemical hydrogen storage is that the release of hydrogen from the carrier requires an input of heat. In many use cases where waste heat from external sources is not available (e.g. in heavy-duty mobility), this is seen as a major drawback. In this paper, we show that autothermal LOHC dehydrogenation offers a very attractive way to overcome this drawback. In detail, we demonstrate autothermal hydrogen release from dicyclohexylmethane using diphenylmethane oxidation to benzophenone as source of heat. The full storage cycle involves benzophenone hydrodeoxygenation to dicyclohexylmethane, dicyclohexylmethane dehydrogenation to diphenylmethane, and diphenylmethane oxidation to benzophenone. We studied both the individual reaction steps using pure feedstocks and the integral cycle in which the intermediates and by-products of each reaction remain in the system for the subsequent reaction step. Although no efforts have yet been made to develop special catalyst materials for this purpose, the results with the applied commercial hydrodeoxygenation (Pd/C), dehydrogenation (Pt on alumina) and partial oxidation (VOx/TiO2) catalysts are already very promising. The storage cycle can be closed with high selectivity and with only minor total oxidation losses. The proposed concept of autothermal LOHC dehydrogenation offers the potential to increase the amount of useable hydrogen from a given amount of charged hydrogen carrier by up to 30%.

Single-Core Double Emulsions The fabrication of single-core double emulsions typically requires sophisticated microfluidic devices and meticulous operation protocols. In article number 2107338, Nicolas Vogel and co-workers develop a convenient method to produce such tailored double emulsions with defined droplet structure using only vortex mixing. This fast, low-cost and high-yield method improves the accessibility of droplet-based materials.

Double emulsions, such as water-in-oil-in-water droplets, are important material platforms for conducting fundamental research and for technological applications. To date, well-defined double-emulsion droplets consisting of a single water core and a thin oil shell can be exclusively formed with sophisticated microfluidic devices. The fabrication, preparation, and operation of such devices is challenging, which reduces the availability of tailored double emulsions to a limited community of experts. Here, a simple method is introduced to produce single-core double emulsions with high yield in large quantities, using a vortex mixer. Utilizing the density difference between the dispersed droplet and the continuous phase, this two-step emulsification method can achieve very small core droplet diameters below 10 μm and ultrathin shells with thicknesses below 1 μm. A detailed picture of the formation mechanism is provided and it is demonstrated that the process can be extended to produce multishell and multicore emulsions. Finally, its application is demonstrated to produce structurally colored colloidal supraparticles with unprecedented uniformity and yield. The method allows the creation of tailored double emulsions with minimal time, cost, effort, and expertise, and may widen its application to nonspecialized scientific communities.

This work is a continuation of previous studies focusing on the influence of intermolecular interactions on the diffusive mass transport in mixtures consisting of liquids with dissolved gases by determining the Fick diffusion coefficient of the mixtures or self-diffusion coefficient of the gas solutes. Dynamic light scattering, Raman spectroscopy, and molecular dynamics simulations are applied to study the interplay between the liquid structure and diffusive mass transport in binary mixtures consisting of methane, neon, krypton, sulfur hexafluoride, and the two refrigerants R143a and R236fa dissolved in n-hexane or 1-hexanol. Experiments and simulations were performed at the macroscopic thermodynamic equilibrium close to infinite dilution of the solute at temperatures between 303 and 423 K. The obtained Fick diffusion coefficients increase with increasing temperature and are always smaller in mixtures based on 1-hexanol compared to those of n-hexane. For both solvents, a decreasing molar mass of the solutes leads to increasing Fick diffusion coefficients with the exception of methane and neon showing the opposite behavior. Next to a general discussion and comparison with the literature, the present diffusivity data are compared with values predicted by a semiempirical model, which was previously developed to predict mass diffusivities in binary mixtures consisting of n-alkanes or 1-alcohols with dissolved gases close to infinite dilution.

Synthesis of bulk chemicals from biogenic resources is gaining increasing interest in industry and academia. In the present study, we demonstrate the continuous production of acrylic acid (AA) from biogenic lactide in a liquid-phase reaction using the ionic liquid tetrabutylphosphonium bromide as reaction medium and 2-bromopropionic acid as acid catalyst precursor. We here present a first continuous setup for AA production from LA derivatives in the liquid phase on a 10 L scale. The process operates at 200 °C and leads to AA yields of 72% in industrially relevant space–time–yields of up to 50 g/(h·L). We demonstrate continuous operation over 6 h time-on-stream, efficient product isolation and successful catalyst recycling.

A new reaction system for the highly selective, hydrobromic acid catalyzed conversion of lactide into acrylic acid under mild conditions is reported. The applied liquid reaction system consists of a temperature-stable bromide-containing ionic liquid and 2-bromopropionic acid as a source of dry HBr, with no volatile organic solvent being used. This allows for the in situ removal of the formed acrylic acid, leading to an unmatched acrylic acid selectivity of over 72 % at full lactide conversion. Accounting for leftover reaction intermediates on the way to acrylic acid, which could be recycled in an elaborate continuous process, the proposed reaction system shows potential for acrylic acid yields well above 85 % in the liquid phase. This opens new avenues for the effective conversion of biogenic lactic acid (e.g., obtained by fermentation from starch) to acrylic acid. The resulting bio-acrylic acid is a highly attractive product for, for example, the diaper industry, where we expect consumers to be especially sensitive to aspects of sustainability.