Showing papers on "Dithiocarbamate published in 1987"

Determination of cobalt, copper, mercury, and nickel as bis(2-hydroxyethyl)dithiocarbamate complexes by high-performance liquid chromatography

Abstract: Ammonium bis(2-hydroxyethyl)dithiocarbamate (HEDC) is used as a precolumn derivatizing reagent for the reversed-phase HPLC determination of Co(II), Cu(II), Hg(II), and Ni(II). The metal-HEDC complexes are soluble in water, which eliminates the need to extract them into an organic solvent prior to analysis. Co(II), Cu(II), and Ni(II) can be determined by direct aqueous injection onto a C18 column in the range of 0.005-10.0 mg/L, with a precision of 1.5-3.2%. Detection is at 405 nm. The Hg(II)-HEDC complex is preconcentrated on an on-line adsorption column prior to HPLC analysis. After preconcentration, Hg(II) can be determined in the range of 0.02-25..mu..g/L with a precision of less than 2%. The analysis of spiked electroplating waste waters showed good agreement with expected values.

Trace enrichment and separation of metal ions as dithiocarbamate complexes by liquid chromatography

Abstract: A method is presented that involves the simultaneous formation of metal dithiocarbamates and on-line preconcentration and, subsequently, separation of heavy-metal ions (Cd(II), Pb(II), Hg(II), Cu(II), Co(II), Ni(II), Bi(III)) by reversed-phase liquid chromatography. A cetrimide-dithiocarbamate ion pair is loaded onto a precolumn packed with C/sub 18/-bonded silica, and the injected metal ions react instantaneously with the dithiocarbamate to form stable complexes. These relatively apolar complexes are efficiently preconcentrated on the precolumn. They can be eluted on-line to C/sup 18/ separation column and, next, separated with an acetonitrile/water gradient containing cetrimide and buffered to pH 6.8. The detection is effected with a UV-vis diode-array detector which allows the determination of subnanogram amounts of metal ions. The cleanup, preconcentration, and automation potential render the method suitable for multimetal analysis in complex samples. Application of this principle to the trace analysis of Cu(II) and Hg(II) in drinking water is demonstrated.

Methods for production of crosslinked rubber products

Abstract: In a process of crosslinking a rubber compound with the usage of an organic peroxide as the crosslinking agent, is incorporated to the rubber compound in an amount of 0.5-20 parts by weight per 100 parts of a rubber substrate a compound selected from imidazole type compounds, thiourea type compounds, thiazole type compounds, thiuram type compounds, dithiocarbamate type compounds, phenol type compounds, triazole type compounds and amine type compounds. The process results no surface tackiness of the rubber product crosslinked in the presence of oxygen.

XPS Studies of Planar Four-Coordinate Copper(II) and Copper(III) Complexes

Abstract: X-ray photoelectron spectra of some planar CuS4 copper N,N-dialkyl dithiocarbamate compounds in the formal +2 and +3 oxidation states and the CuO4 complex carbonate, Na2[Cu(CO3)2], have been recorded. Cu(2p3/2) binding energies for the copper(II) dithiocarbamate and carbonate compounds are similar although the `shakeup' satellite structure for the dithiocarbamate compounds is relatively less intense. The modified Auger parameter, α', for the two sets of compounds is also similar but ca. 1-2 eV lower than the value reported for the most Cu(II) compounds. The copper binding and kinetic energy parameters for the Cu(III) compounds have been found to correspond to values found for the Cu(II) compounds with, however, an absence of secondary satellite structure. Differences between the compounds in the two oxidation states are also found in the ligand sulphur 2p binding energies which are ca. 1 eV higher in the Cu(III) compounds.

Dithiocarbamate compostions having increased rain fastness

Abstract: The rain fastness of dithiocarbamates in dry form is enhanced by formulation with nonionic water-soluble polymer comprising hydroxy(C 2 -C s ) alkyl cellulose, polyethylene oxide, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide and/or polyvinylmethylether in an amount of from about 0.1 to about 5 weight percent based on the weight of the dithiocarbamate.

Synthesis of a Dithiocarbamate Chelate Resin and Its Oxidized form and Their Adsorption Properties for Heavy Metal Ions

Abstract: A series of macroporous dithiocarbamate chelate resins, III and V, and an oxidized resin, VI, with high adsorption capacity were prepared. The influence of various reaction conditions of amination, dithiocarboxylation, and oxidation were examined. The structure and the conversion of functional groups of resins were confirmed by IR spectra and elemental analysis. The adsorption capacities of Resin II for Hg2+, Cu2+, Zn2+, and Cd2+ are 4.40, 2.44, 1.77, and 1.36 mmol/g, respectively. The adsorption capacities of Resins V and VI for Cu2+. Zn2+, Ni2+, Co3+, Ag+, Hg2+, Cd2+, Pb2+, and Au3+ are 4.07–0.51 and 3.81–0.59 meq ion/g, respectively. The adsorption rate and the influence of pH on the adsorption percentage of the resins for metal ions were examined. Noble metal, transitional metal, and heavy metal ions can be quantitatively adsorbed by the resins. The adsorbed Cu2+, Pb2+, Cd2+, Co3+, and Ni2+ can be quantitatively eluted with 5N HNO3, and the presence of large amounts of Ca2+, Mg2+, Fe3+, and A...

Synthesis of 1,2,3,4-tetrahydro-beta-carboline derivatives as hepatoprotective agents. III. Introduction of substituents onto methyl 1,2,3,4-tetrahydro-beta-carboline-2-carbodithioate.

Abstract: Dithiocarbamates of various substituted tetrahydro-β-carbolines were synthesized and tested for hepatoprotective activity against carbon tetrachloride (CCl4) -induced liver damage in mice. Structure-activity relationships were investigated. Some neighboring group participation of the 3-substituent with the dithiocarbamate group appeared to be important for the manifestation of activity. The compounds (1a, 2a, and 3i) with hydrophilic substituents at the 3 poisition exhibited significant activity. Substitution at the 9 position of the 3-carboxylic acid (1a) lowered the activity.

Headspace gas chromatography of carbon disulphide in the determination of dithiocarbamate fungicide residues

Abstract: The determination of residues of dithiocarbamate fungicides by headspace gas chromatography of CS2 following acid degradation is subject to error if the calibration of the flame photometric detector is affected by the solvent used to prepare the CS2 standards. Hexane co-elutes with CS2 on a 1% OV-17 + 4% QF1 column packing, resulting in the quenching of the sulphur emission in the detector. The use of other solvents or column packings in the determination avoids this problem.

Über Chalkogenolate. 181 [1]. Thiocarbamoyl‐methylsulfane

Abstract: Die Thiocarbamoyl-methylsulfane H2NCSSxCH3, CH3NHCSSxCH3 und (CH3)2NCSSxCH3 mit x = 1 und 2 wurden nach bekannter Verfahren (fur x = 1) bzw. durch Umsetzung des entsprechenden Dithiocarbamats mit dem S-Methylester der Methanthiosulfonsaure CH3SO2SCH3 (fur x = 2) hergestellt. Die Verbindungen wurden mit verschiedenen spektroskopischen Methoden untersucht. On Chalcogenolates. 181. Thiocarbamoyl Methyl Sulfanes The thiocarbamoyl methyl sulfanes H2NCSSxCH3NHCSSxCH3, and (CH3)2NCSSxCH3 with x = 1 and 2 have been prepared by known procedures (for x = 1) and by reaction of the corresponding dithiocarbamate with the S-methylester of methanethiosulfonic acid CH3SO2SCH3 (for x = 2). The compounds have been studied by means of diverse spectroscopic methods.

Dithiocarbamate internal mold release agents

Abstract: A method of making a reaction injection molded polyurethane having enhanced mold release properties is provided. An effective amount at least one dithiocarbamate is injected into a mold cavity with at least one a polyisocyanate component and at least one an active hydrogen component. Polyurethanes having enhanced mold release properties are formed using a composition of matter comprising at least 0.25 parts per hundred parts by weight of active hydrogen components of a dithiocarbamate of the formula: ##STR1## wherein M and the R groups are described herein.

Chemistry of dithiocarbamate derivatives of amino acids. Part III. X-ray photoelectron spectroscopy of Ba(S2CNHCH2CO2)·3H2O. I.r. and e.s.r. studies of α-amino acid-dithiocarbamate complexes of copper(II)

Abstract: Coordination compounds [Cu(S2CNHCHRCO2H)2], were obtained by reaction of dithiocarbamate derivatives of amino acids with copper(II), and the products were characterized by i.r. and e.s.r. spectroscopy. The xps spectrum of Ba(S2CNHCH2CO2)·3H2O is reported.

Synthesis and characterization of poly([3H]‐thiazole‐2‐thione)s

Abstract: The reaction of dithiocarbamate salts with α-haloketones is extended to (i) dithiocarbamate salts with bis(α-haloketones), (ii) bis(dithiocarbamate salts) with α-haloketones, and (iii) bis(dithiocarbamate salts) with bis(α-haloketones). Both (i) and (ii) give bis([3H]-thiazole-2thiazole-2-thiones) in high yields, and (iii) gives the corresponding polymers which are described and characterized.

Improved lubricating oil composition

Abstract: A lubricating composition having improved anti-wear properties comprises: A. a lubricating oil basestock; B. a metal phosphate; C. a metal carbamate; and D. an alkyl hydroxy-aryl sulfide. The metal phosphate is preferably a dialkylphosphate, zinc compounds being especially suitable. From about 0.1 to about 1.0 wt.% (based on the basestock) is preferred. The metal carbamate is preferably a dithiocarbamate, more especially zinc compounds. From about 0.1 to about 1.3 wt.% is preferred. The sulfide is preferably an alkyl phenol sulfide, for example, nonyl phenol sulfide. From about 0.2 to about 2 wt.% is preferred.

Preparation of alkyl thiosemicarbazides

Abstract: The present invention relates to a process for the preparation of alkyl semicarbazides by reaction of a dithiocarbamate and hydrazine in a weakly basic reaction media using a metal rearrangement catalyst

Method of preparing hydrocarbon substituted dithiocarbamates molybdenum

Abstract: An improved process for preparing dihydrocarbyl substituted dithiocarbamates of molybdenum wherein an alkali metal hydroxide is reacted with a mixture of a dihydrocarbyl substituted amine and carbon disulfide in an aqueous solution to produce an alkali metal salt of dithiocarbamate and the alkali metal salt then reacted with an alkali metal molybdate in the presence of acid to produce the dihydrocarbyl substituted dithiocarbamate of molybdenum. The process is completed in an inert atmosphere and within a relatively narrow range of temperatures so as to avoid the production of by-products which have heretofore reduced both the yield and purity of the final product. The preparation of the alkali metal salt of dithiocarbamate is completed at a temperature generally within the range from about -5 to about 30° C. The acidification of the alkali metal salt of dithiocarbamate is completed, generally, at a temperature within the range from about -5 to about 5° C.

Process for production of isothiocyanates

Abstract: Isothiocyanates are formed by oxidizing, with gaseous oxygen or air, in the presence of a metal oxidation catalyst a dithiocarbamate with appropriate control of the pH of the reaction medium to suppress the formation of by-products. Optionally a quaternary ammonium halide catalyst can be used to increase product yield.

High Performance Liquid Chromatography of Organic and Inorganic Anions Using a Micellary Mobile Phase

Abstract: Ion pairing chromatography has been widely used for the chromatographic determination of ionizable solutes. To date, the most commonly used ion-pairing reagents are non-micelle forming, but there can be advantages in using the micelle forming reagents. For example, no method existed previously for the separation and determination of dithiocarbamate salts, widely used as fungicides. High-performance liquid chromatography using micellar hexadecyltrimethylammonium chloride as the mobile phase provides a versatile and efficient technique for the separation of iodate, nitrite, bromide, nitrate and iodide. The distribution and retention of the inorganic anions is governed by their partitioning between the micelles and the mobile phase, and between the conditioned stationary phase and the mobile phase. Dithiocarbamate salts of varying hydrophobicity can be separated using micellar hexadecyltrimethylammonium bromide. Chromatographic efficiency measurements obtained for the hydrophobic solutes (phenol and benzene) and the ionic dithiocarbamate salts show that efficiency remains high even with high concentrations of methanol as the mobile phase modifier, with acetonitrile as the modifier, the efficiency falls as the concentration increases.

Process for colouring wood.

Abstract: Wood impregnated with preferably chromium/copper-based wood-preserving salts can be stained easily and in a manner resistant to the weather, if it is treated with an aqueous solution of a dithiocarbamate compound.

The effects of various additives on the regioselectivity of the reactions of allyl dithiocarbamate with aldehydes.

Abstract: アリルニジチオカルバメートのリチウム塩とアルデヒドの反応における添加物のレギオ選択性に対する影響を検討した。添加物として4種の典型金属元素の塩,3種のクラウンエーテル,および4種のLewis酸を選び,実験した。これら添加物中Ti(OPri)4がもっともいちじるしい効果を示し,98%の選択率でα-付加体を与えた。この反応の機構としてカルボニル基がチタン原子に配位した六員環いす形遷移状態を仮定し,結果を説明した。

Stabilised biocidal compositions based on metal dithiocarbamate

Abstract: Biocidal compositions capable of being suspended in water, consisting of a solid phase based on metal dithiocarbamate (in particular zinc and/or manganese dithiocarbamate) as active substance dispersed in a liquid aqueous phase containing, as dispersing and stabilising agent, at least one water-soluble copolymer derived from at least one ethylenically unsaturated carboxylic acid and from at least one ethylenically unsaturated sulphonic acid salt.

Electrochemical study of triphenyltin piperidyl dithiocarbamate

Abstract: The reduction of triphenyltin piperidyl dithiocarbamate in acetone has been investigated using d.c. polarography and cyclic voltammetry. Polarographic reduction yielded four well-defined waves, two of which were diffusion-controlled and two of which appear to represent adsorption processes. The cyclic voltammetric study yielded results in close agreement with the polarographic data. Results appear to indicate the release of the dithiocarbamate moiety, followed by reduction to form the triphenyltin radical, which undergoes dimerization, as well as reduction to the triphenyltin anion. For comparison, the polarographic reduction of triphenyltinchloride was investigated. A mechanism similar to that proposed by earlier authors for the polarographic behaviour of tributyltin oxide was found.