The reaction of ethylene sulfide with isothiocyanates

Ethylene sulfide reacts with isothlocyanates in the presence of triethylamine catalyst at 20°C, to give low-molecular copolymerization products having the general formula [-C(NR)-S-CH₂-CH₂-S-]n. Their hydrolysis gives a salt of the amine and [-C(O)-S-CH₂CH₂S-]_n. Vacuum-heating the latter gives ethylenedithiocarbonate, and hydrogen peroxide oxidation in formic acid gives ethane disulfonic acid. Treatment of the copolymer from phenyl isothiocyanate and ethylene sulfide with liquid ammonia, amines, or aqueous alkali results in splitting and formation of 2-phenylimino-1,3-dithiolane, while its reaction with ethylene oxide in the presence of triethylamine gives 3-phenyloxazolid-2-one.

     

The reaction of ethylene sulfide with isothiocyanates

Ethylene sulfide reacts with isothlocyanates in the presence of triethylamine catalyst at 20°C, to give low-molecular copolymerization products having the general formula [-C(NR)-S-CH₂-CH₂-S-]n. Their hydrolysis gives a salt of the amine and [-C(O)-S-CH₂CH₂S-]_n. Vacuum-heating the latter gives ethylenedithiocarbonate, and hydrogen peroxide oxidation in formic acid gives ethane disulfonic acid. Treatment of the copolymer from phenyl isothiocyanate and ethylene sulfide with liquid ammonia, amines, or aqueous alkali results in splitting and formation of 2-phenylimino-1,3-dithiolane, while its reaction with ethylene oxide in the presence of triethylamine gives 3-phenyloxazolid-2-one.     

The reaction of OH radicals with dimethyl sulfide

The kinetics of the gas phase reaction of OH radicals with dimethyl sulfide (CH₃SCH₃) have been studied at various temperatures and total pressures using two relative rate methods and a flash photolysis technique. For the relative rate methods, rate constants were measured at 296 ± 2 K as a function of the O₂ pressure at a total pressure of ca. 740 torr. Data from these three experimental techniques were not in agreement. It is concluded that the relative rate techniques are subject to secondary reactions, possibly involving CH₃S radicals. A rate constant of (2.5) × 10^?12 e^{(130 = 102)/T} cm³ molecule^?1 s^?1 obtained using the flash photolysis-resonance fluorescence data in the absence of O₂, and which is in agreement with the lower range of values previously reported in the literature, is recommended.     

The reaction of selenium dichloride with divinyl sulfide

A synthesis of novel selenium heterocycles based on the reaction of selenium dichloride with divinyl sulfide has been described. At −50 °C the reaction affords 2,6-dichloro-1,4-thiaselenane in quantitative yield. At room temperature the reaction gives 2,6-dichloro-1,4-thiaselenane and 5-chloro-2-chloromethyl-1,3-thiaselenolane. Upon standing in chloroform solution, 2,6-dichloro-1,4-thiaselenane undergoes spontaneous rearrangement to 5-chloro-2-chloromethyl-1,3-thiaselenolane. Under the action of pyridine, 2,6-dichloro-1,4-thiaselenane is converted to 2-chloromethyl-1,3-thiaselenole in 95% yield.     

Chemisorption of hydrogen sulfide on lead sulfide

The hydrogen sulfide chemisorption on lead sulfide at 22–100°C is studied by static testing in a vacuum and by pulsed chromatography. It is established that H₂S is sorbed in reversible and irreversible forms and that the process is accompanied by the sample charging. Irreversibly sorbed hydrogen sulfide is removed by heating the sample in a vacuum or in an inert-gas stream at temperatures exceeding the adsorption temperature by 30–50°C.     

The reaction of lead tetraacetate with hydrocarbons

The free radical reaction of lead tetraacetate with hydrocarbons has been investigated. The products of these reactions are the acetate esters. The hydrogen abstracting species from lead tetraacetate is found to have a primary to secondary to tertiary selectivity of 1:27:123 based upon relative reactivities.     

The formation and properties of mixed lead sulfide—silver sulfide membranes for lead(II)-selective electrodes

The preparation and behaviour of a lead(II)-selective electrode made of mixed silver sulfide-lead sulfide are discussed and compared with those of a copper(II)-selective electrode. X-ray diffraction showed that hot-pressing of the membrane causes changes in the crystalline structure of the material. Responses to lead(II), sulfide, and hydroxide were measured ; potential-pH curves were determined in solutions containing EDTA, NTA, Tetren or Trien with and without the lead complex. The results are similar to those obtained for the copper-i.s.e. Data are given for titrations, selectivity coefficients, and response times. The response of the lead-i.s.e. to an addition of ligand is faster for Trien than for EDTA. This difference is large for the copper-i.s.e. These response rates may be correlated with potential-pH curves in the presence of ligands.     

Geometry of lead sulfide nanoparticles with a NaCl-type structure

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One-pot synthesis of lead sulfide nanoparticles

A convenient and effective one-pot three-component synthesis of the lead sulfide nanoparticles was developed on the basis of the exchange reaction between the lead acetate and sodium sulfide in water at the ambient conditions. A possibility was shown of the direct reaction between the lead Pb²⁺ and sulfide S²⁻ ions in an aqueous solution, resulting in a solid phase which contained PbS nanoparticles only, avoiding the hydrolysis stage.     

Kinetic-spectrophotometric determination of sulfide by its reaction with resazurin

A sensitive, rapid and selective method for the determination of sulfide based on its reaction with resazurin at pH 7 is described. The method is simple and has the great advantage of being free from interference of other sulfur anions and thus sulfide can be easily determined at trace levels in the presence of other sulfur compounds. The method has been applied to some synthetic samples and a spring water sample. The importance of sulfide compounds in biological processes has been widely demonstrated [1]. However, most of the methods used so far are either not sensitive enough or require complicated and expensive instruments; or are subjected to interferences from other sulfur compounds. Therefore, more sensitive, simple and selective methods are still required.     

Oxidation of nanocrystalline lead sulfide in air

The oxidation of nanocrystalline PbS powders with a particle size of 10–20 nm and the oxidation of ∼100-nm-thick nanocrystalline PbS films with a crystallite size of 70–80 nm have been investigated in the temperature range from 293 to 773 K. The nanocrystalline powders and films were prepared by chemical deposition from aqueous solutions. The nanopowders with a particle size of 10–20 nm begin to oxidize at a 450 K lower temperature than bulk lead sulfide (870 K). The PbS nanofilms are more resistant to oxidation than the nanopowders and are stable in air up to 573 K. The oxidation behavior of the nanopowders and nanofilms is in agreement with the sulfate theory of PbS oxidation.     

锂在非层状硫化物中的电化学嵌入反应I:锂在硫化铅中的嵌入过程

通过库伦滴定、三角波电位扫描和X射线衍射物相分析,研究了Li/PbS电池的阴极反应机理.发现在该电池放电的第一个阶段(放电深度小于1.5),阴极上发生的是锂嵌入硫化铅晶格的反应,并且锂嵌入后硫化铅的主晶格结构基本未变,锂进入了晶体的立方体间隙中心位置.测得锂嵌入硫化铅生成LiPbS的嵌入自由能为-300.48kJ.mol^-^1(25℃),锂在LiyPbS(0相似文献   

Kinetic-spectrophotometric determination of sulfide by its reaction with resazurin

A sensitive, rapid and selective method for the determination of sulfide based on its reaction with resazurin at pH 7 is described. The method is simple and has the great advantage of being free from interference of other sulfur anions and thus sulfide can be easily determined at trace levels in the presence of other sulfur compounds. The method has been applied to some synthetic samples and a spring water sample. The importance of sulfide compounds in biological processes has been widely demonstrated [1]. However, most of the methods used so far are either not sensitive enough or require complicated and expensive instruments; or are subjected to interferences from other sulfur compounds. Therefore, more sensitive, simple and selective methods are still required.     

Pyramidal lead sulfide crystallites with high energy {113} facets

A new, generic method to exercise control over the shape of crystallites is reported. Crystals of PbS are grown in the unusual form of pyramids at the water-toluene interface. The pyramids are single crystalline and adopt a unique growth habit (slow growth along [113] direction). The pyramids are exclusive products of the reaction and are obtained in the form of a monolayered film spread across the fluid interface. The origins of the growth habit and assembly lie in phenomena unique to the liquid-liquid interface. The dimensions of the pyramidal base can be controllably varied in the range 575-1260 nm. Crystallites of other forms such as rods and spheres can be obtained by varying the properties of the fluid interface.     

Electrochemical intercalation reaction of lithium into sulfides of nonlayer structure: I. Lithium intercalation in lead sulfide

The reaction mechanism of cell Li/PbS has been studied with coulombic titration, cyclic voltammetry and X-ray diffraction methods. It was found that in the first stage of discharge (0< y ≤1.5), the intercalation of lithium into lead sulfide took place. The X-ray diffraction patterns showed that the main crystalline structure of PbS remained unchanged after lithiation, and the lithium intercalated probably locates in the center of the cubic-interspace of the crystal. The intercalation free energy of Li into PbS forming LiPbS was found to be ?300.48 KJ·mol^?1 (at 25°C). The chemical diffusion coefficient of lithium in Li_yPbS (0<y≤1) was determined by electrochemical method to be about 10^?11 cm²S-1.