A Review and Experimental Revisit of Alternative Catalysts for Selective Oxidation of Methanol to Formaldehyde

The selective oxidation of methanol to formaldehyde is a growing million-dollar industry, and has been commercial for close to a century. The Formox process, which is the largest production process today, utilizes an iron molybdate catalyst, which is highly selective, but has a short lifetime of 6 months due to volatilization of the active molybdenum oxide. Improvements of the process’s lifetime is, thus, desirable. This paper provides an overview of the efforts reported in the scientific literature to find alternative catalysts for the Formox process and critically assess these alternatives for their industrial potential. The catalysts can be grouped into three main categories: Mo containing, V containing, and those not containing Mo or V. Furthermore, selected interesting catalysts were synthesized, tested for their performance in the title reaction, and the results critically compared with previously published results. Lastly, an outlook on the progress for finding new catalytic materials is provided as well as suggestions for the future focus of Formox catalyst research.

Synthesis reactions of neutron-rich isotopes of light elements

One of the most complicated problems of experimental nuclear physics is the synthesis of exotic nuclei near the boundaries of stability. These nuclei, as a rule, are 10 or more neutrons away from stable nuclei, have a short lifetime (less than 1 ms) and low binding energy. All this determines special requirements to the choice of reactions for the synthesis of such nuclei and the method of their transportation and registration. Mainly, for the synthesis of exotic nuclei, reactions of fragmentation of the bombarding heavy ion, direct reactions of the types (p, d) , (d, p) , (d, n) , ( d , 3 He), etc., as well as reactions of fission and deep inelastic transfer are used.

Enhancing plasmonic hot-carrier generation by strong coupling of multiple resonant modes

Plasmon-induced hot carriers have recently attracted intensive research, but the energy efficiency in the visible light is often low due to the short lifetime of hot carriers and the limited...

Engineering COFs as Smart Triggers for Rapid Capture and Controlled Release of Singlet Oxygen

Capture and controlled release of singlet oxygen (1O2) are of great significance but very challenging due to its very short lifetime and high reactivity. Addressing this challenge, we rationally designed...

Deciphering the Role of Positions 145 and 165 in Fluorescence Lifetime Shortening in the EGFP Variants

The bright ultimately short lifetime enhanced emitter (BrUSLEE) green fluorescent protein, which differs from the enhanced green fluorescent protein (EGFP) in three mutations, exhibits an extremely short fluorescence lifetime at a relatively high brightness. An important contribution to shortening the BrUSLEE fluorescence lifetime compared to EGFP is provided by the T65G substitution of chromophore-forming residue and the Y145M mutation touching the chromophore environment. Although the influence of the T65G mutation was studied previously, the role of the 145th position in determining the GFPs physicochemical characteristics remains unclear. In this work, we show that the Y145M substitution, both alone and in combination with the F165Y mutation, does not shorten the fluorescence lifetime of EGFP-derived mutants. Thus, the unlocking of Y145M as an important determinant of lifetime tuning is possible only cooperatively with mutations at position 65. We also show here that the introduction of a T65G substitution into EGFP causes complex photobehavior of the respective mutants in the lifetime domain, namely, the appearance of two fluorescent states with different lifetimes, preserved in any combination with the Y145M and F165Y substitutions.

The potential of satellite data to calculate the global OH distribution using simplified steady state approximations

<div> <p>The hydroxyl radical (OH) is one of the most important species in atmospheric chemistry. It plays a dominant role in the oxidation of many other species in the troposphere, such as anthropogenic pollutants. Direct in-situ and satellite measurements of OH are scarce due to its short lifetime (around 1 second) and low abundance. Other indirect methods of inferring global mean OH have been established, such as using methyl chloroform as a tracer. However because of its recent phase out there is a demand for another method of calculating the global OH abundance. It is therefore useful to explore indirect methods for calculating OH. In particular, global satellite data can provide a means for estimating mean OH within large atmospheric regions. An improved understanding of the global distribution of OH will allow a better understanding of atmospheric chemistry, especially the distributions of anthropogenic pollutants.  </p> </div><div> <p>Due to the short lifetime of OH, a steady-state approximation can be used to model its concentration. This allows the OH distribution to be calculated using a simple equation and the accuracy of the estimate depends on the number of source/sink terms which can be included in the equation. In this work, a steady state approximation has been applied to the global OH budget as defined in the TOMCAT 3-D model. The full steady-state equation (based on all reactions in the model) has been simplified in various ways to include only the major sources and sinks of OH that can be observed directly by satellite, such as carbon monoxide (CO), methane (CH4), water vapour (H2O) and ozone (O3). </p> </div><div> <p>Recent satellite observations of these species is then applied to the steady-state approximation to derive an estimate of the global OH distribution. We use the 3-D model to determine where the simplified steady-state approximation is likely to be most valid. The overall potential of this method to calculate an accurate OH distribution, bearing in mind satellite observation errors, is discussed. </p> </div>

Augmentation of the Life Time of Cyclo[18]carbon Accustomed with Carbon Nanotube and Zeolite

Recently synthesized cyclo[18]carbon which is characterized as polyyne D_9h has a very short lifetime even at 5 K temperature. Its automerization is proposed through a transition state which is reported as a D_18h symmetric cumulene. <div>In the present article, an experimentally viable method for the enhancement of the lifetime of this compound is reported. The carbon nanotube is employed for this purpose. We also report that adopting numerous molecules of cyclo[18]carbon in the womb of a zeolite cage, wire-like countenance construction is feasible.</div>