FeCo nanoalloys embedded in nitrogen-doped carbon nanosheets/bamboo-like carbon nanotubes for the oxygen reduction reaction

Herein, FeCo bimetallic organic frameworks (MOFs) with different compositions were fabricated by controlling the initial molar ratio of Fe3+/Co2+ ions.

Investigation of propylene carbonate synthesis regularities by the interaction of propylene glycol with carbamide

Objectives. Cyclic carbonates are important products of organic synthesis, which are widely used as solvents, catalysts, and reagents for the production of various compounds (in particular, urethane-containing polymers) by the non-isocyanate method. The process of carbamide alcoholysis with polybasic alcohols is a promising method for the synthesis of cyclic carbonates. The purpose of this study is to determine the reaction conditions for the interaction of propylene glycol with carbamide in the presence of zinc acetate as a catalyst.Methods. We conducted experiments to study the synthesis of propylene carbonate in a batch laboratory apparatus. Moreover, we analyzed the starting reagents and final products using gas–liquid chromatography.Results. We studied the synthesis of propylene carbonate by carbamide alcoholysis with propylene glycol in the presence of a catalyst (zinc acetate) by varying the following parameters: initial molar ratio of propylene glycol/carbamide = (0.5–5):1, synthesis temperature 130–190°С, reagent residence time in the reactor 0.5–4 h, and the catalyst amount in the reaction mixture 0–1.5 wt %.Conclusions. We determined the technological parameters of propylene carbonate synthesis in a batch reactor. Moreover, we showed that the process allowed the production of propylene carbonate with a sufficiently high yield of 80%—at the initial molar ratio of propylene glycol/ carbamide = 3:1, temperature 170°C, and residence time 2 h.

Identification of Phosphate Precipitates from Wastewater Digested Liquor

The XRD and EDX analyses were used to identify the type of phosphate precipitate from anaerobically digested liquor of wastewater screenings. The measurements confirmed that the main phosphate compound produced from the experiments was CaCO3 and HA when the Mg:P molar ratios were 1.56:1 and 2:1, respectively. The precipitation at 1.56:1 was the initial molar ratio without chemical amendment, whereas 2:1 was carried out by chemical amendment. The results indicate that the presence of foreign ions such as calcium ion in high concentration may affect the formation of phosphate precipitates. This study shows that precipitation at 2:1 is suitable to recover phosphorus from wastewater digested liquor in the form of HA, as proved by the XRD pattern and further supported by EDX analysis. According to previous studies, the phosphate precipitate has a potential as a fertiliser or soil conditioner that can be used for agricultural purpose.

Influence of the Mixing Ways of Reactants on ZnO Morphology

ZnO particles with various morphologies were synthesized by mixing ZnSO4and NaOH solutions at 25°C followed by aging of the suspensions at 40–80°C for 2.0 h, keeping the initial molar ratio of Zn2+to OH−at 1 : 4. ZnO irregular plates were prepared by adding NaOH to ZnSO4whileε-Zn(OH)2rhombic particles were produced using the opposite mixing way. After aging of the slurries at 80°C for 2.0 h, the ZnO plates were kept stable while theε-Zn(OH)2rhombic particles were converted to ZnO whiskers with a length of 1.0–4.0 μm and a diameter of 0.03–0.3 μm. Thermodynamic analysis indicated that the formation of the Zn-bearing precipitates (ZnO orε-Zn(OH)2) at room temperature was connected closely with the solution composition.

Telomerization of 3,3,3-Trifluoroprop-1-ene and Functionalization of Its Telomers

The synthesis of four 3,3,3-trifluoroprop-1-ene telomers (RF(C3H3F3)nI, n = 1, 2, RF = n-C6F13- or (CF3)2CF-) and their allyl derivatives RF(C3H3F3)nCH2CH=CH2 are presented. The allyl telomers were prepared by a three-step reaction. The first step involved the thermal and peroxide-induced bulk telomerization of 3,3,3-trifluoroprop-1-ene (TFP) with heptafluoro-2-iodopropane or tridecafluoro-6-iodohexane leading to monoadduct and diadduct, the ratio of which depends on the R0 = [RFI]0/[TFP]0 initial molar ratio and the reaction temperature. The amount of monoadduct increased up to 50-60% and of the diadduct to 25-30% at temperatures up to 180 °C (thermal-initiated) and 150 °C (initiated with di-tert-butyl peroxide, DTBP), R0 up to 1.5. It was observed that the addition of the (CF3)2CF• radical onto the =CH2 of TFP was regioselective leading to selective formation of a single isomer in contrast to the addition of the n-C6F13• radical. Then, the telomers reacted with allyl acetate yielding RF(C3H3F3)nCH2CH(I)CH2OCOCH3 (n = 1, 2) in 50-80% yields. The third step consisted of a deiododeacetatization of these iodoacetates into RF(C3H3F3)nCH2-CH=CH2 (C,n) giving 50-80% yields. All the intermediates were characterized by 1H, 19F and products by 13C NMR spectroscopy.

Titanium-Catalyzed [4+2] and [6+2] Cycloadditions of 1,4-Bis(trimethylsilyl)buta-1,3-diyne

The (C2H5)2AlCl/TiCl4 catalyst induces the [4+2] cycloaddition of butadiene or the [6+2] cycloaddition of 1,3,5-cycloheptatriene (CHT) to individual acetylenic moieties of 1,4-bis(trimethylsilyl)buta-1,3-diyne (BSD). Heating of the 2:1 butadiene adduct, bis(2-trimethylsilylcyclohexa-1,4-dien-1-yl), to 250 °C yields 2,2'-bis(trimethylsilyl)biphenyl. The 1:1 adduct of BSD with CHT, 7-trimethylsilyl-8-trimethylsilylethynylbicyclo[4.2.1]nona-2,4-diene, is obtained as virtually the only product if the initial molar ratio CHT : BD equal to 1.86 is used.