Hydrometallurgical recycling of valuable metals from spent lithium-ion batteries by reductive leaching with stannous chloride

The reductant is a critical factor in the hydrometallurgical recycling of valuable metals from spent lithium-ion batteries(LIBs).There is limited information regarding the use of SnCl_(2) as a reductant with organic acid(maleic acid)for recovering valuable metals from spent Li-CoO_(2) material.In this study,the leaching efficiencies of Li and Co with 1 mol·L^(−1) of maleic acid and 0.3 mol·L^(−1) of SnCl_(2) were found to be 98.67%and 97.5%,respectively,at 60°C and a reaction time of 40 min.We investigated the kinetics and thermodynamics of the leaching process in this study to better understand the mechanism of the leaching process.Based on a comparison with H_(2)O_(2) with respect to leaching efficiency,the optimal leaching parameters,and the activation energy,we determined that it is feasible to replace H_(2)O_(2) with SnCl_(2) as a leaching reductant in the leaching process.In addition,when SnCl_(2) is used in the acid-leaching process,Sn residue in the leachate may have a positive effect on the re-synthesis of nickel-rich cathode materials.Therefore,the results of this study provide a potential direction for the selection of reductants in the hydrometallurgical recovery of valuable metals from spent LIBs.

Stannous oxalate as a novel catalyst for the synthesis of polytrimethylene terephthalate

Stannous oxalate was prepared efficiently and characterized by XRD and FT-IR. It exhibited higher catalytic activity and had profitable effect than tetrabutyl titanate and stannous octoate for the synthesis of polytrimethylene terephthalate （PTT） via esterification-route. Over this catalyst, the degree of esterification of pure terephthalic acid was up to 94.4% at 260 ℃ after 1.5 h,while the intrinsic viscosity and content of terminal carboxyl groups of the corresponding PTT polyester, polymerized at 260 ℃,60 Pa for 2 h, was 0.8950 dL/g and 15 mol/t, respectively. Stannous oxalate was a promising catalyst for the synthesis of PTT polyester.

Stannous oxalate: An efficient catalyst for poly(trimethylene terephthalate) synthesis

A complete study on the catalytic activity of stannous oxalate for poly(trimethylene terephthalate) (PTT) synthesis via esterification method is carried out by comparison to the well known catalysts (tetrabutyl titanate (TBT), dibutyltin oxide (Bu2SnO), and stannous octoate (SOC)). Their catalytic activity in the esterification process is monitored by measuring the amount of water generated, while intrinsic viscosity (IV) and content of terminal carboxyl groups (CTCG) are used as the index in the polycondensation process. Stannous oxalate shows higher activity than the other catalysts. Decrease in reaction time and improvements in PTT property are observed. The higher catalytic activity of stannous oxalate is attributed to its chelate molecular structure.

Study on the stannous halides promoted addition of 1,1,1-trichloro-2,2,2-trifluoroethane to aldehydes and the chemical transformation thereof

Promoted by stannous salts, 1,1,1-trichloro-2,2,2-trifluoroethane reacts readily with aliphatic, aromatic, and α, β-unsaturated aldehydes giving the corresponding alcohols bearing a CF3CCl2-moiety in good to excellent yields. These alcohols are farther oxidized by Jones reagent giving the corresponding ketones in high yields.

Additive effects on tin electrodepositing in acid sulfate electrolytes

The effects of additives on the stannous reduction of an acid sulfate bath were investigated using cyclic and linear sweep voltammetry, electrochemical impedance spectroscopy （EIS）, and microstructure analysis. In the absence of additives, tin coatings are rough, and the tin electrodepositing is a single-step reduction process accompanied by hydrogen gas evolution. The addition of tartaric acid produces a slight reduction in the peak current of stannous reduction and has an appreciably positive effect on the stability of the acidic tin bath. Both benzylidene acetone and polyoxyethylene octylphenol ether hinder the stannous reduction and greatly suppress the hydrogen gas evolution. Formaldehyde slightly decreases the peak current density of stannous reduction and serves as an auxiliary brightener in the acid sulfate bath. The presence of mixed additives greatly suppresses the stannous reduction and hydrogen gas evolution and consequently produces a significantly smoother and denser tin coating. The （112） crystal face is found to be the dominant and preferred orientation of tin deposits.

New Approach to Synthesis of 6,7-Dimethoxyisatin

A new approach to synthesis of 6,7-dimethoxyisatin is reported. 2-nitro-3, 4- dimethoxy mandelonitrile in glacial acetic acid was treated with the solution of stannous chloride in hydrochloric acid to give 6, 7-dimethoxyisatin in a high yield.

Preparation and Tribological Performance of Novel Organotin Compound as Lubricant Additive

Oil-soluble stannous naphthenate (SN) is synthesized by using naphthenatic acid and SnO. And its molecular structure is confirmed by IR and multielement oil analyzer (MOA). The tribological performances of the organotin as lubricant additive are evaluated with a four-ball friction and wear tester. These experiments indicate that the wear scar diameter (WSD) and friction coefficient are diminished while the load-carrying capability increased by comparison with that of base oil. The elemental composition of the boundary lubricating film is examined by means of Auger electron spectroscopy (AES). Synergistic effect is found in the load-carrying capability of the complex of SN and sulfured olefin. The analytical results of AES indicate that the good performance of stannous naphthenate is attributed to the formation of a boundary lubricating film containing Sn on the rubbed surface.

Synthesis and Characterization of Poly（Lactide）s Using Novel Solid Cloisite Modified Tin Catalyst

A novel cloisite modified solid catalyst was prepared in a single step from commercially available starting materials for the first time. The ring opening polymerization of L-lactide and D-lactide using this cloisite modified solid catalyst resulted in homopolymers of 75,000 and PDI = 1.6 and the maximum molecular weight （Mw） i.e. 180,000 with PDI = 1.9 were obtained. The catalytic activity ofcloisite modified solid catalyst was compared with the conventional stannous octoate catalyst and found superior to stannous octoate in all respect such as conversion, molecular weight and molecular weight distribution etc.. Moreover, the maximum molecular weight i.e. 180,000 was obtained at 220 ℃, whereas, transesterification reaction predominate in presence of stannous octoate The linear structure was confirmed by quantitative ^13C NMR Spectroscopy. Blend films were obtained by casting mixed solutions of poly （D-lactide） and poly （L-lactide） at various compositions, and stereocomplex was formed at 50/50 composition with molecular weight of 75,000.

Realizing high thermoelectric performance of Cu and Ce co-doped p-type polycrystalline SnSe via inducing nanoprecipitation arrays

Thermoelectric(TE)performance of polycrystalline stannous selenide(SnSe)has been remarkably promoted by the strategies of energy band,defect engineering,etc.However,due to the intrinsic insufficiencies of phonon scattering and carrier concentration,it is hard to simultaneously realize the regulations of electrical and thermal transport properties by one simple approach.Herein,we develop Cu and Ce co-doping strategy that can not only greatly reduce lattice thermal conductivity but also improve the electrical transport properties.In this strategy,the incorporated Cu and Ce atoms could induce high-density SnSe_(2) nanoprecipitation arrays on the surface of SnSe microplate,and produce dopant atom point defects and dislocations in its interior,which form multi-scale phonon scattering synergy,thereby presenting an ultralow thermal conductivity of 0.275 W·m^(−1)·K^(−1) at 786 K.Meanwhile,density functional theory(DFT)calculations,carrier concentration,and mobility testing reveal that more extra hole carriers and lower conducting carrier scattering generate after Cu and Ce co-doping,thereby improving the electrical conductivity.The co-doped Sn_(0.98)Cu_(0.01)Ce_(0.01)Se bulk exhibits an excellent ZT value up to~1.2 at 786 K and a high average ZT value of 0.67 from 300 to 786 K.This work provides a simple and convenient strategy of enhancing the TE performance of polycrystalline SnSe.

Synthesis of 2,5-disubstitued benzimidazole using SnCl_2-catalyzed reduction system at room temperature

Stannous chloride dihydrate is used as an efficient catalyst in reductive cyclization of 2-nitro-5- substituted aniline Schiff base leading to stable 2,5-disubstitued benzimidazole derivatives in excellent yields with good purity. It provides a novel method of synthesis of 2,5-disubstitued benzimidazole under reductive system at room temperature.