Maximizing the [c2]daisy chain to lasso ratio through competitive self-templating clipping reactions

Self-templating two-component coupling reactions allowed the isolation of two threaded products with different molecular sizes: a lasso-type [1]rotaxane and a [c2]daisy chain rotaxane. Their distribution in the final reaction mixture...

One tool to bring them all: Au-catalyzed synthesis of B,O- and B,N-doped PAHs from boronic and borinic acids

Singly and doubly B,E-doped PAHs were synthesized using a protocol that starts from easy-to-handle boronic and borinic acids and offers the possibility to choose between the preparation of B,O- and B,N-PAHs in the final reaction step.

RT-LAMP assay for ultra-sensitive detection of SARS-CoV-2 in saliva and VTM clinical samples

The COVID-19 pandemic has underscored the shortcomings in the deployment of state-of-the-art diagnostic platforms. Although several PCR-based techniques have been rapidly developed to meet the growing testing needs, such techniques often need samples collected through a swab, the use of RNA extraction kits, and expensive thermocyclers in order to successfully perform the test. Isothermal amplification-based approaches have also been recently demonstrated for rapid SARS-CoV-2 detection by minimizing sample preparation while also reducing the instrumentation and reaction complexity. There are limited reports of saliva as the sample source and some of these indicate inferior sensitivity when comparing RT-LAMP with PCR-based techniques. In this paper, we demonstrate an improved sensitivity assay to test saliva using a 2-step RT-LAMP assay, where a short 10-minute RT step is performed with only B3 and BIP primers before the final reaction. We show that while the 1-step RT-LAMP demonstrate satisfactory results, the optimized 2-step approach allows for single molecule sensitivity per reaction and performs significantly better than the 1-step RT-LAMP and conventional 2-step RT-LAMP approaches with all primers included in the RT Step. Importantly, we demonstrate RNA extraction-free RT-LAMP based assays for detection of SARS-CoV-2 from VTM and saliva clinical samples.

COSMETIC PRODUCTION FROM GLYCERINE THE BIODIESEL

The present study aims to produce a cosmetic emulsion containing the co-product glycerine, generated in the production of biodiesel by the transesterification of canola oil. The first part of the work consisted in the production of biodiesel by the transesterification of crude canola oil, using potassium hydroxide as catalyst, with a molar ratio of oil:methanol (1:6) and a temperature of 25 °C. The final reaction mixture had to be washed and filtered to obtain biodiesel, which was characterized and considered within the specifications of the National Oil Agency (ANP). The second step was based on the pre-purification of the glycerine by acid hydrolysis, by the addition of concentrated phosphoric acid/crude glycerin in the 2:3 molar ratio. This step was important to remove impurities such as the catalyst and fatty acids to later use the glycerine in the manipulation of the cream. Finally, the formulations of the Lanette® cream were made, one with the pharmaceutical glycerine other for the pre-purified glycerine of the biodiesel, and comparative tests were made among them, which proved the viability of the pre-purification of the residual glycerine of the biodiesel.

Experimental Study on Thermal and UV-enhanced Gas-Solid Chlorination of High-Density Polyethylene

The dynamic process of gas-solid chlorination of high-density polyethylene (HDPE) was revealed using a vibrated-bed reactor, where a UV-Vis measurement system was used to record the kinetics of chlorination online. Thermal and UV-enhanced chlorination at fixed temperature below the melting point (Tm) of HDPE were firstly investigated. It was observed that UV irradiation could accelerate the reaction rate. However, all of the prepared chlorinated polyethylene (CPE) products had unchlorinated crystal structures and a limitation of chlorine content. Multi-stage chlorination was hence designed for more homogeneous chlorination and decreasing the residual crystallinity. The differential scanning calorimetry (DSC) results showed effective decrease of the melting enthalpy (ΔHm) while the final reaction temperature was beyond Tm. Meanwhile, the presence of -CH = CH- bonds in the polymer chain revealed by solid-state nuclear magnetic resonance (S-NMR) indicated that the final reaction temperature should not be higher than 150 °C.

Reaction kinetics of Cu2-xS, ZnS, and SnS2 to form Cu2ZnSnS4 and Cu2SnS3 studied using differential scanning calorimetry

ABSTRACTDifferential scanning calorimetry experiments on mixed Cu2-xS, ZnS, and SnS2 precursors were conducted to better understand how Cu2ZnSnS4 (CZTS) and Cu2SnS3 form. The onset temperatures of Cu2SnS3 reactions and CZTS suggest that the ZnS phase may mediate Cu2SnS3 formation at lower temperatures before a final CZTS phase forms. We also found no evidence of a stable Cu2ZnSn3S8 phase. The major diffraction peaks associated with Cu2ZnSnS4, and Cu2SnS3 (overlaps with ZnS, as well) began to grow around 380 °C, although the final reaction to form Cu2ZnSnS4 probably did not occur until higher temperatures were reached. An exothermic reaction was observed corresponding to formation of this phase. There was some variability in the onset temperature for reactions to form Cu2SnS3. At least 5 steps are involved in this reaction and several segments of the reaction had relatively reproducible energies.

From N-vinylpyrrolidone anions to modified paraffin-like oligomers via double alkylation with 1,8-dibromooctane: access to covalent networks and oligomeric amines for dye attachment

The double alkylation of N-vinylpyrrolidone (N-VP) with 1,8-dibromooctane yields paraffin-like oligomeric chains bearing polymerizable vinyl moieties. These oligomers were radically crosslinked in bulk with N-VP as co-monomer yielding swellable polymer disks. The vinylic side groups of the N-VP oligomers allow thiol–ene click reactions with 2-aminoethanethiol hydrochloride to obtain reactive amino-functionalized oligomers. Further modification of the free amino groups with 1,4-difluoro-9,10-anthraquinone (DFA) yields red-colored oligomeric anthraquinone dyes. The final reaction of DFA-substituted N-VP oligomers with Jeffamine® M 600 leads to blue-colored and branched oligomers with poly(ethylene glycol) side chains.