Turning CO/CO2-containing industrial process gas into valuable building blocks for the polyurethane industry

Provided is a concept of how the carbon content of CO/CO2-containing blast furnace gas (BFG) from steel production could be utilized in a sequence of selective chemical conversion steps to produce high value intermediates for the polymer industry.

Synthesis and Antimicrobial Activity of (Z)-2-(4-((5-((1-Benzylpiperidin-4-yl)methylene)- 2,4-dioxothiazolidin-3-yl)methyl)-1H-1,2,3-triazol-1-yl)-N-phenylacetamides

In current times, researchers adopted the click chemistry approach for the synthesis of various druglike molecules by using a few reliable, feasible, practical and selective chemical transformations via click formation. In present work, we focussed on the most triazole clubbed thiazolidine-2,4-dione derivatives as the most promising motifs for broad biological application. A total of fifteen (CF-4a-o) derivatives were synthesized and well characterized with various analytical techniques.

A One-Pot Biocatalytic and Organocatalytic Cascade Delivers High Titers of 2-Ethyl-2-Hexenal from n-Butanol

Biocatalysis provides facile access to selective chemical transformations and helps satisfy sustainable chemical production criteria. However, the reaction scope of biocatalysts is significantly narrower compared to synthetic chemical transformations. Hybrid biocatalytic-chemocatalytic cascades expand the scope of products while maintaining many of the benefits associated with biocatalysis. Here, we report that single-pot systems with whole cell K. pastoris (ATCC® 28485™) or isolated enzyme alcohol oxidase (E 1.1.3.13) as oxidative biocatalysts with a lysine organocatalyst yields the commercial target, 2-ethyl-2-hexenal (2-EH) from n-butanol in a two-step hybrid cascade. Peak yields for both biocatalysts were achieved with 100 mM n-butanol at pH 8 and 30°C. The isolated enzyme slightly outperformed whole cell K. pastoris, reaching 73% conversion (4.7 g/L titers) compared to 61% (3.9 g/L titers) in whole cells systems. Titers could be improved for both biocatalysts (5.7 – 6.7 g/L) at increased butanol loading; however, this came at the expense of decreased yields. Compared to our initial results with a Gluconobactor oxidans whole cell biocatalyst, the reported system improves upon 2-EH titers by 2.8-3.3-fold at maximal yields.

Selective Chemical Labeling and Sequencing of 5-Hydroxymethylcytosine in DNA at Single-Base Resolution

5-Hydroxymethylcytosine (5hmC), the oxidative product of 5-methylcytosine (5mC) catalyzed by ten-eleven translocation enzymes, plays an important role in many biological processes as an epigenetic mediator. Prior studies have shown that 5hmC can be selectively labeled with chemically modified glucose moieties and enriched using click chemistry with biotin affinity approaches. Besides, DNA deaminases of the AID/APOBEC family can discriminate modified 5hmC bases from cytosine (C) or 5mC. Herein, we developed a method based on embryonic stem cell (ESC) whole-genome analysis, which could enrich 5hmC-containing DNA by selective chemical labeling and locate 5hmC sites at single-base resolution with enzyme-based deamination. The combination experimental design is an extension of previous methods, and we hope that this cost-effective single-base resolution 5hmC sequencing method could be used to promote the mechanism and diagnosis research of 5hmC.

Preparation and Characterization of Highly Porous Polyacrylonitrile Electrospun Nanofibers Using Lignin as Soft Template via Selective Chemical Dissolution Technique

In this study, polyacrylonitrile (PAN) was mixed with a renewable polymer, lignin, to produce electrospun nanofibers by using an electrospinning technique. Lignin was utilized as a soft template that was removed from the nanofibers by using a selective dissolution technique to create porous PAN nanofibers. These nanofibers were characterized with Fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM), thermogravimetry analysis (TGA), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) to study their properties and morphology. The results showed that lignin can be homogeneously mixed into the PAN solution and successfully electrospun into nanofibers. FESEM results showed a strong relationship between the PAN: lignin ratio and the diameter of the electrospun fibers. Lignin was successfully removed from electrospun nanofibers by a selective chemical dissolution technique, which resulted in roughness and porousness on the surface of the nanofibers. Based on the BET result, the specific surface area of the PAN/lignin nanofibers was more than doubled following the removal of lignin compared to PAN nanofibers. The highest specific surface area of nanofibers after selective chemical dissolution was found at an 8:2 ratio of PAN/lignin, which was 32.42 m2g−1 with an average pore diameter of 5.02 nm. The diameter of electrospun nanofibers was also slightly reduced after selective chemical dissolution. Porous PAN nanofibers can be seen as the precursors to the production of highly porous carbon nanofibers.

Fabrication of lithium niobate fork grating by laser-writing-induced selective chemical etching

We propose and experimentally demonstrate a laser-writing-induced selective chemical etching (LWISCE) technique for effective micro-fabrication of lithium niobate (LN) crystal. Laser writing of LN crystal produces negative domains and domain walls. Also, it causes local lattice defects, in which the etching rates are significantly increased in comparison to the original LN crystal. In experiment, we use the LWISCE technique to fabricate various fork gratings in an X-cut LN crystal for the generation of vortex beams. In comparison to etching an untreated X-cut LN crystal, the etching rates of the laser-writing-induced boundaries and the central laser-irradiated areas are enhanced by a factor of 26 and 16, respectively. The width and depth of fork grating structure can be precisely controlled by laser writing parameters. Our method provides an efficient mask-free micro-fabrication technique for LN crystal, which can be readily applied to other ferroelectric crystals such as lithium tantalate, potassium titanyl phosphate and barium calcium titanate.

Thin nanocrystalline semiconductor films as selective chemical sensors for ammonia, acetone and other donors

Studied are the films of variously doped polycrystalline n-semiconductors (ZnO, SnO2) as selective sensitive elements (SE) of chemical sensors for various gases and vapours (ammonia, acetone, propane, ethanol, hexane, solvent, turpentine etc.) in artificial air. It has been revealed that their conductivity changes under temperature modulation makes possible data processing which identifies the impurities above. This processing is based on nonlinear regression estimation of so called principal parameters which set is unique for every concentration of every of the gases/vapours.