The application of the highly efficient ruthenium catalyst [Ru(CO)2{P(p‐CF3–C6H4)3}2(O2CPh)2] (1) in the selective syn‐addition of carboxylic acids to internal alkynes, yielding valuable trisubstituted enol esters with (E)‐configuration, is described. All reactions feature excellent stereoselectivities and good regioselectivities. The regioselectivity is dictated by electronic and steric aspects of the alkyne substituents and the acidity of the carboxylic acid. The catalytic activity can be significantly increased by the addition of catalytic amounts of B(C6F5)3. Relative to known catalysts for the synthesis of (E)‐enol esters, this methodology offers improved selectivity and requires lower catalyst loadings. Moreover, a broad range of alkynes and carboxylic acids can be successfully converted to their corresponding (E)‐enol esters in high yields.

The presented investigation focuses on the development of a novel microgap reactor concept for the photocatalytic degradation of micropollutants from aqueous solutions with titanium dioxide-based catalysts immobilized by spray coating. Combinatorial experiment designs were utilized in order to study the influence of the microgap width, irradiance and catalyst layer thickness on the conversion of 17 α-ethinyl estradiol. The impact of catalyst-doping is discussed as well. Regarding conversion analyses, LC-MS/MS and GC-MS techniques were deployed, while XRD, ESEM and BET were utilized for catalyst characterization. The results show that the built-up microgap reactor system enables a conversion of 65% within a residence time of 2.7 min with UV-A irradiation and under steady flow conditions. Thus, the presented bench scale photocatalysis reactor provides promising fundamental findings for the future development of pilot scale approaches. With the deployment of industrial catalysts and base materials, microgap reactor photocatalytic degradation represents an attractive technology for large-scale application.

The rising pollution of surface water by endocrine disruptive chemicals (EDCS) could lead to the persistent harm of aquatic wildlife. Addressing this concern, advanced waste water treatment techniques should be established in addition to the present sewage treatment. Therefore, the promising advanced oxidation process of photocatalysis is discussed. With the aim of establishing a novel high throughput screening approach for photocatalysts, a workflow resting upon the use of a self-constructed 60-fold parallel stirring UV-A LED photoreactor, followed by parallel sample extraction by SPE and sequential automated analysis by GC-MS, was developed, and is presented in this article. With the described system, TiO 2 -based photocatalysts, doped with different amounts of zinc, and synthesised by a sol-gel-route, were tested regarding their activity in the photocatalytic degradation of the synthetic estrogen 17α-ethinylestradiol. Thereby, the functional behavior of the photoreactor system and its applicability in a high throughput process could be evaluated. As a result of the catalyst screening, TiO 2 catalysts with low amounts of zinc were found with a significantly higher activity, compared to undoped TiO 2 . In conclusion, the presented system provides an easily accessible high throughput method for a variety of photocatalytic experiments.Materials 2020, 13, 1365 2 of 17 active [11]. To maintain the conditions of fresh water, municipal sewage treatment plants are introduced to the hydrological cycle, but it has been reported in literature that it is not possible to sustainably remove a plurality of micropollutants, and therefore EDC, from our wastewaters with the widespread activated sludge process [12][13][14][15]. In addition to this common type of sewage treatment, advanced oxidation processes (AOPs) like ozonation [16][17][18][19][20][21], or physical removal techniques like nanofiltration [22][23][24][25] and adsorption to charcoal [26][27][28][29][30], have been discussed lately. While these additional treatments deliver satisfying results regarding the reduction of micropollutants, they are inseparably linked to certain disadvantages, such as the generation of hazardous products and the disposal of adsorbents. Another, and presumably the most promising treatment procedure, is the photocatalysis [31][32][33][34], which is another variant of an AOP. Concerning the semiconductor materials utilised in this process, titanium dioxide (TiO 2 ) is the most established and examined one [35][36][37][38][39][40][41][42][43]. Apart from the fact that it is already known that estrogens could be degraded satisfactorily with the help of photocatalysis making use of TiO 2 , only few information has been gathered respecting reaction kinetics, matrix effects, reaction products, doped TiO 2 catalysts, and other semiconductors completely differing in their composition from TiO 2 for the deployment in photocatalytic reactions. For targeting these research subjects in depth, it is essential to implement procedures which enable a con...

The high‐throughput screening investigations on TiO2 based photocatalyst composites presented here have been carried out in a 60‐fold parallel photoreactor. Additional catalyst testing was performed in a microslit reactor system with immobilized catalysts. For further enhancing the photocatalytic activity of TiO2 (P25), composites of P25 and, for example, Bi2O3, CeO2, g‐C3N4, WO3 or ZnO were formulated in different nominal molar ratios. The catalysts' performances were assessed by their conversion of 17α‐ethinyl estradiol (EE2) in aqueous solutions, determined by LC–MS. Findings show rapid EE2 conversions in short residence times. The extensive testing of catalysts led to the conclusion that the photocatalytic conversion is rather a function of residence time than a function of the materials utilized. This makes adequate process development seem more important than material development. The novelty of this contribution lies in the unique combination of testing a wide range of composite catalysts in a unique microreactor geometry.

The reaction of benzoic acids and alkynes proceeds with excellent E/Z‐selectivity furnishing the E‐isomers of the respective alkenylbenzoates only.