Amount Of Lithium Chloride Research Articles

Tritium separation from heavy water using a membrane containing deuterated manganese dioxide

This study reports the separation of tritium from tritiated heavy water at room temperature using a membrane containing deuterated manganese dioxide. A continuous decrease in the tritium concentration in tritiated heavy water was observed when using the membrane. Furthermore, the dissolution of manganese ions from the membrane into tritiated heavy water was remarkably decreased by adding an adequate amount of lithium chloride to the tritiated heavy water.

Effects of LiCl/DMSO dissolution and enzymatic hydrolysis on the chemical composition and lignin structure of rice straw

The exploration of solvent system to completely dissolve lignocellulosic biomass is of great important for the development of biomass based materials and chemicals. Dimethyl sulfoxide containing certain amount of lithium chloride (LiCl/DMSO) was proved an effective solvent system for the dissolution of ball-milled wood. In this paper, four samples of rice straw, internode (stem without node), stem, leaf (leaf and sheath) and whole straw, with and without 1 h of ball milling treatment, were used to investigate the effects of their dissolution in LiCl/DMSO solvent on the chemical composition of regenerated and enzymatically hydrolyzed materials. Because of the structural difference from wood, samples expose d to 1 h of milling were almost completely dissolved. The chemical nature of the regenerated material and of residual after enzymatic hydrolysis of rice straw was analyzed and the susceptibility of this rice straw to the enzymatic hydrolysis was evaluated.

Fractionation and Characterization of Wood Cell Wall Components of Fagus crenata Blume Using LiCl/DMSO Solvent System

The fractionation of wood cell wall components was achieved by the application of the LiCl/DMSO solvent system developed in our previous study. Various soluble and insoluble fractions were prepared from beech milled wood by extractions with DMSO containing different amounts of lithium chloride (LiCl) for the study of a lignin-carbohydrate complex (LCC). Nitrobenzene oxidation (NO) analyses demonstrated that the lignin in the soluble fractions always has lower yields of NO products consisting of syringaldehyde + syringic acid (Sy) and vanillin + vanillic acid (Va). The syringyl ratios, Sy/(Sy+Va), were also lower than in insoluble fractions. Accordingly, lignins with lower syringyl ratios are better soluble than those with higher syringyl ratios. The former is typical in the primary wall and the latter in the secondary wall. Solubilization of glucan is significantly dependent on the LiCl concentration in DMSO. In the absence of LiCl, only about 6% of glucan was found in the soluble fraction, but about 40% of lignin and xylan were solubilized. The additional 40% of lignin and xylan became soluble together with glucan solubilization, which increased at 3% LiCl concentration. However, a fraction amounting to 13% (based on the whole wood) still remained as a residue under these conditions. Glucan solubilization could not be the reason for this observation as ball-milled cellulose is soluble in 3% LiCl/DMSO. It is likely that strong interactions between lignin and carbohydrates prevent solubilization of this fraction, which has never been isolated and analyzed in previous studies.

Effects of the addition of LiCl, LiClO4, and LiCF3SO3salts on the chemical structure, density, electrical, and mechanical properties of rigid polyurethane foam composite

AbstractThe effect of the incorporation of several lithium salts on the electrical and mechanical properties of polyurethane rigid (PUR) foams was investigated. Different amounts of lithium chloride (LiCl), lithium perchlorate (LiClO4), and lithium trifluoromethanesulfonate (LiCF3SO3) were added to the polyuretanic precursor. The salts affected the cellular microstructures and consequently the mechanical properties of the composite. Composite foams containing an amount of LiCl greater than 2 wt% showed low‐surface resistivity (∼106Ω), whereas the LiClO4and LiCF3SO3composites showed, in all range of filler percentage analyzed, high‐surface resistivity values (∼1011Ω). This behavior was related to the different interactions between PUR and lithium salts, as confirmed by FTIR/Attenuated Total Reflectance analysis. Only the LiCl was able to create a motion of the ions Li+and Cl−along the polyurethanic chains, because LiCl was completely dissociated. On the contrary, LiClO4and LiCF3SO3that affected the macromolecular structure of the polymeric network did not permit the formation of polyurethanic channels, where the ions could move, thus creating a charge motion. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers

Further Studies on the Anionic Copolymerization of Styrene and Glycidyl Methacrylate in Toluene

Sequential anionic copolymerization of styrene and glycidyl methacrylate (GMA) was performed with the protection of argon under normal pressure, where styrene, GMA, toluene, THF, n-butyllithium and a small amount of lithium chloride (LiCl) were used as first monomer, second monomer, solvent, polar reagent, initiator and additive, respectively. Polystyrene-b-poly(glycidyl methacrylate) diblock copolymers (PS-b-PGMA) with well-defined structure and narrow molecular weight distribution were prepared by the copolymerization reaction of poly(styryl)lithium with GMA under certain temperatures. The copolymers were characterized using gel permeation chromatography (GPC), 1H-NMR, 13C-NMR, thin layer chromatography (TLC) and hydrochloric acid-dioxane argentimetric methods. The effects of additives, copolymerization temperature and THF dosage on the copolymerization were studied. No chain transfer reaction of anionic polymerization of styrene in toluene was observed. Slightly broader molecular weight distribution of PS-b-PGMA was observed with the increase the GMA repeat units. Using THF/toluene blend solvent could reduce the polydispersity index (M w /M n ) and dissolve the copolymer better than toluene alone. Lower temperature (< -40°C) and LiCl are required to prepare PS-b-PGMA with narrower molecular weight distribution.

Nickel nanoparticles in hydrogen-transfer reductions: Characterisation and nature of the catalyst

Nickel nanoparticles, readily prepared by reduction of nickel(II) chloride with lithium and a catalytic amount of DTBB, have been used in the transfer hydrogenation of carbonyl compounds and have been fully characterised by different means. The reaction rate of the transfer hydrogenation was found to be dependent on the acetophenone and isopropanol concentration but independent on the amount of lithium chloride. The deactivation of the catalyst after reuse has been mainly attributed to surface oxidation but not to coke formation. All the experiments performed are in agreement with the process being of heterogeneous nature. The nickel nanoparticles unveiled a superior behaviour in comparison with commercially available nickel catalysts.

A Facile Synthetic Approach to the Preparation of 3-Pyridyl Derivatives: Preparations and Coupling Reactions of 3-Pyridylzinc and Its Analogues

A facile synthetic approach to the direct preparation of 3-pyridylzinc bromide has been demonstrated using Rieke zinc with 3-bromopyridine in the presence of a catalytic amount of lithium chloride. A variety of different electrophiles have been coupled to give the corresponding cross-coupling products in moderate to good yields. Also, this methodology has been expanded to the preparation of the corresponding organozinc reagents of 3-bromopyridine analogues.

State of lithium cation in a solution of polyurethane in deviethylformamide

The viscosity characteristics of solutions of PU in DMF containing different amounts of lithium chloride and perchlorate wer investigated. The dependence of the relative viscosity of the ternary systems LiX—PU—DMF on the type and content of the lithium salt was established. A hypothesis was advanced concerning the coordination of lithium cations with polyurethane functional groups.

Study of the Propagation Center in the Anionic Polymerization of (Meth)acrylic Monomers: NMR and MNDO Study of the Complexes of Di-tert-butyl 2-Lithio-2,4,4-trimethylglutarate and of the Living Poly(tert-butyl methacrylate) Oligomers with Lithium Chloride

Interactions of living oligomers of tert-butyl methacrylate (tBuMA) with a Li counterion and of the model living dimer di-tert-butyl 2-lithio-2,4,4-trimethylglutarate (A) with LiCl (B) were studied in tetrahydrofuran-d8 (THF-d8) solution by 7Li, 6Li, 1H, and 13C, 1D and 2D, NMR spectroscopy. Di-tert-butyl 2-lithio-2,4,4-trimethylglutarate is shown to form a 1:1 complex with lithium chloride in THF. 1H, 7Li NMR results suggest that a rapid equilibrium between free LiCl and the mixed complex takes place when the molar ratio LiCl:lithiated dimer is higher than 1. From 13C relaxation times, a dimeric aggregation (i.e. A2B2) of the complex is deduced, in full accord with MNDO calculations. Preliminary results are presented for living tBuMA oligomers prepared by initiation with diphenylhexyllithium in the presence of various amounts of lithium chloride. Fast-acquired 13C NMR spectra of the living ends were recorded using 13C-enriched monomer added at the end of the polymerization. Their structure is shown to be...

Lithium chloride as an enhancing agent for metaphase preparations from rodent lymphocytes.

Circulating lymphocytes of many mammals, especially rodents, have proven refractory to PHA stimulation of mitotic activity. Addition of small amounts of lithium chloride to the culture medium removes the refractoriness and increases the yield of metaphase cells 7 fold. This simple procedure makes possible the routine use of circulating lymphocytes in rodent karyology.

Adiabatic polymerization of ε‐caprolactam in presence of lithium chloride, 2. Properties of the resultant polymer

AbstractPhysical and mechanical properties of poly(ε‐caprolactam) synthesized in presence of various amounts of lithium chloride are measured on compression moulded films and correlated to the molecular organization, both in the amorphous and in the crystalline regions. By increasing the amount of LiCl present in the system it can be observed a heigtening of Tg and density of the amorphous phase as well as an increase of tensile modulus and yield strength. A transition from ductile to brittle failure occurs for both semicrystalline and amorphous samples in dry conditions, when the salt content in the amorphous phase is about 6 wt.‐%. These phenomena and the capability of the salt to reduce the crystallinity of the polymer are interpreted in the frame of the already accepted model of ion‐dipole interactions between lithium ion and the carbonyl groups of the polyamide. Effects due to moisture uptake are also discussed.

The effect of lithium on the iodide concentrating mechanism in mouse salivary gland.

The iodide concentrating mechanism, measured as the gland to plasma (G/P) 125I- concentration ratio, was measured in male mouse submandibular glands after the animals had been fed with varying amounts of lithium chloride for intervals ranging from 0 to 8 weeks. After acute exposure (by injection) to lithium the G/P 125I- fell compared to control values and was further depressed at high serum lithium values. Chronic exposure to lithium was characterised by an increase in the G/P 125I- ratios at therapeutic serum lithium concentrations. It is suggested that lithium has a direct effect on the iodide concentrating mechanism that may be independent of any action of thyroid stimulating hormone during this process. The effect may be important in the formation of lithium induced goitre.

Reaction of N-p-tolylsulphonylsulphimides with halide ion in dimethylformamide

The halide ion catalysed rearrangement of N-p-tolylsulphonylsulphimides [Ar–S(Ts)–R; R = Me or PhCH2] was found to afford nearly quantitatively the corresponding sulphenamide [ArSN(Ts)R] and is considered to proceed through a Stevens-type intramolecular rearrangement. The kinetic study revealed that the rate of the reaction of S-aryl-S-methyl-N-p-tolylsulphonylsulphimides with lithium chloride in dimethylformamide obeys a second-order kinetic equation v=k2[Sulphimide][LiCl]. However, the lithium chloride concentration remained constant throughout the reaction, i.e. v=kapp[Sulphimide]. This suggests that the reaction is catalysed by chloride ion. Furthermore, with only a 1/10 molar amount of lithium chloride the sulphimide afforded the rearranged product quantitatively. The activation parameters for the reaction are ΔH‡ 26·7 kcal mol–1 and ΔS‡–4·1 cal mol–1 K–1 respectively, and a Hammett ρ value of +1·7 was obtained. When the reaction of S-methyl-S-phenyl-N-p-tolylsulphonylsulphimide with LiCl was carried out in the presence of benzyl chloride, the only rearranged product obtained was N-benzyltoluene-p-sulphonamide. Methyl chloride formed in this reaction was trapped as methyl p-tolyl sulphide upon addition of toluene-p-thiolate. These observations suggest that the catalytic rearrangement proceeds through initial formation of alkyl halide and subsequent alkylation of sulphenamide anion involving a rate-determining nucleophilic attack of halide ion on the α-carbon atom attached to the trivalent sulphur atom of the sulphimide.

An Improved Electrical Hygrometer and Its Applications*

The electric hygrometer consists of an aluminum tube coated with polystyrene and wound with a bifilar winding of bare palladium wire. The unit is then coated with a thin film of polyvinyl acetate with an amount of lithium chloride in it depending upon the humidity range to be covered. The electrical resistance of the film between the two coils is a function of humidity. If appreciable temperature changes are involved, a correction is applied. The thin aluminium tube enables the unit to quickly assume the temperature of the air as it must if measuring relative humidity. The palladium wire prevents an increase in resistance caused by a film which forms on the surface of other types of wires. The polystyrene forms an excellent water-resistant surface of high electrical resistance for the wire and water sensitive film, which prevents a hysteresis effect caused by the absorption of water by glass and other materials originally used as bases. The polyvinyl acetate forms a porous binder for the lithium chloride which gives stability and uniformity to the units without appreciably decreasing their rapid rate of response. With several units of different sensitivity in parallel, with resistors in series with each, humidities from 10 to 100% may be measured using a single scale of an indicating instrument. Electrical hygrometer units have been made which have not varied more than 2 to 3% over a period of several months. Flight tests with two radiosondes carried by the same balloon, one using the electric hygrometer and the other the hair type hygrometer, showed marked changes in humidity recorded by the electric hygrometer which the hair unit failed to register.