Presence Of Ammonium Thiocyanate Research Articles

Visible light-induced thiocyanation of gem-difluorinated phosphonium salts

gem-Difluorinated phosphonium salts were generated from nitrones by methylation and reaction with (triphenylphosphonio)difluoroacetate. The phosphonium salts were subjected to visible light-induced phosphonium–thiocyanate exchange in the presence of ammonium thiocyanate, copper thiocyanate, and an iridium photocatalyst. The sequence of the reactions was performed in one pot affording thiocyanates attached to the difluoromethylene fragment.

Green extraction of Cu (II) in PEG-zinc sulfate aqueous two phase system using response surface methodology

The present study investigated the partition and extraction conduct of Cu (II) in Aqueous Two-Phase Systems (ATPS) of Poly (Ethylene Glycol) (PEG)–zinc sulfate in the presence of ammonium thiocyanate as an extractor. The polymer weight percent in the feed (20, 25, and 30%), salt weight percent in the feed (15, 23, and 31%), polymer molecular weight (2000, 4000, and 6000 g.mol-1), and the pH (2.5, 3.6, and 4.7) are the determiners of the partition coefficient of Cu (II) in the target system. The Central Composite Design (CCD) was taken into account to investigate the impacts of various parameters on the partition coefficient of Cu (II) by a quadratic model. High F-value (50.58), very low P-value (<0.0001), non-significant lack of fit, the determination coefficient (R2 = 0.9793) demonstrate an excellent correlation between experimental and predicted values of the response. The model results indicated that the pH and weight percent of the salt in the feed had major and minor effects on the copper ion partition coefficient, respectively. The pH of ATPS can alter the Cu (II) partition coefficient through the variation of the copper ion net charge. The weight percent of polymer in the feed decreased the partition coefficients. Moreover, by increasing the polymer molecular weight, the partition coefficient of Cu (II) was increased. The highest value for the productivity of Cu ions extraction was found to be 93.3% with regard to the excellent separation factors (pH = 4.7, PEG molecular weight = 6000, PEG concentration = 20 and salt concentration = 15)

Antigenic cross-reactivity and species-specific identification of Pseudocerastes persicus fieldi snake venom

In the present study, we recognized progressively high immunological cross-reactivity between Pseudocerastes persicus fieldi (Pf) venom and six other medically important Egyptian snake venoms belonging to families Viperidae and Elapidae. Antibodies with a range of bonding strengths were shown to be involved in such cross-reactivity. Two strategies have been tried to access specificity; (i) using affinity purified species-specific anti-Pf antivenom antibodies, (ii) conducting the assay in the presence of ammonium thiocyanate (NH4SCN). The discrimination power of the prepared species-specific antivenom was demonstrated by its ability to detect Pf venom over a range of Pf concentrations (2.5 ng–2.5 μg) in a variety of body fluids. The assay could distinguish circulating Pf antigens from other viper antigens in the whole blood of experimentally envenomed mice. What seems promising in our work is the use of the chaotrope, NH4SCN, which renders the reaction medium more favorable for the specific homologous antigen-antibody interactions, primarily via preventing lower avid antibodies to share and, to a bit lesser extent, by decreasing non-specific absorbance signals frequently encountered with ELISA assays. The ELISA described herein may be useful for clinicians for identification of snake bites inflicted by Pf snake species. Balancing between specificity and sensitivity has to be considered for best results.

Synthesis, crystal structures, and antibacterial activities of manganese(II) and copper(II) complexes derived from 2-bromo-4-chloro-6-[(2-hydroxyethylimino)methyl]phenol

ABSTRACTReaction of the tridentate Schiff base 2-bromo-4-chloro-6-[(2-hydroxyethylimino)methyl]phenol (HL) with manganese and copper salts in the presence of ammonium thiocyanate in methanol afforded a new mononuclear complex, [MnL2]·0.5H2O (1), and a new dinuclear complex, [Cu2L2(NCS)2] (2). The complexes were characterized by single-crystal X-ray diffraction, FT-IR, and elemental analysis. The Mn atom in complex 1 is coordinated by two tridentate Schiff base ligands, forming octahedral coordination. The Cu atom in complex 2 is coordinated by one tridentate Schiff base ligand, and two thiocyanate ligands, forming square pyramidal coordination. The free Schiff base and the complexes were assayed for antibacterial activities. Both complexes are more active against the bacteria than the free Schiff bases. Complex 2 has the MIC value of 0.20 μg mL−1 against Bacillus subtilis.

Indirect determination of ampicillin sodium with sodium nitrate-ammonium thiocyanate-water system by extraction-flotation of cuprous thiocyanate

A novel method for indirect determination of ampicillin sodium by the extraction-flotation is proposed in this paper. It is indicated that the degradation of ampicillin sodium took place in the presence of 0.30 M sodium hydroxide in boiling water for 20 min. At pH 4.0, in the presence of ammonium thiocyanate, the thiol group of the degradation product of ampicillin sodium could reduce copper(II) to copper(I) due to the formation of the emulsion cuprous thiocyanate precipitation. By determining the residual amount of copper(II) in the solution and calculating the flotation yield of cuprous thiocyanate, the indirect determination of ampicillin sodium can be performed. When the concentration of cooper(II) was 5.0 μg/mL, a good linear relationship was obtained between the flotation yield of cuprous thiocyanate and the amount of ampicillin sodium in the range of 0.40∼9.6 μg/mL. The linear equation is E = 4.1469 + 3.7949c with the correlation coefficient r = 0.9992, and the detection limit (3σ/K) of 0.37 μg/mL. Each parameter has been optimized and the reaction mechanism has been studied. The method has been successfully applied to the determination of ampicillin sodium in pharmaceutical, human plasma and urine samples. Analytical results obtained are satisfactory.

Electrochemical thiocyanation of nitrogen-containing aromatic and heteroaromatic compounds

An efficient and convenient anodic thiocyanation of nitrogen-containing (hetero)aromatic compounds is described under constant current conditions in the presence of ammonium thiocyanate in methanol at room temperature. We have examined the in situ thiocyanation of various aromatic compounds in the presence of electrochemically generated thiocyanogen at a graphite electrode (the anode) in an undivided cell.

Indirect Determination of Ampicillin Sodium with Sodium Nitrate–Ammonium Thiocyanate–Water System by Extraction-Flotation of Cuprous Thiocyanate

A novel method for indirect determination of ampicillin sodium by the extraction⎯flotation is proposed in this paper. It is indicated that the degradation of ampicillin sodium took place in the presence of 0.30 M sodium hydroxide in boiling water for 20 min. At pH 4.0, in the presence of ammonium thiocyanate, the thiol group of the degradation product of ampicillin sodium could reduce copper(II) to copper(I) due to the formation of the emulsion cuprous thiocyanate precipitation. By determining the residual amount of cop per(II) in the solution and calculating the flotation yield of cuprous thiocyanate, the indirect determination of ampicillin sodium can be performed. When the concentration of cooper(II) was 5.0 μg/mL, a good linear relationship was obtained between the flotation yield of cuprous thiocyanate and the amount of ampicillin sodium in the range of 0.40~9.6 μg/mL. The linear equation is E = 4.1469 + 3.7949c with the correlation coefficient r = 0.9992, and the detection limit (3σ/K) of 0.37 μg/mL. Each parameter has been optimized and the reaction mechanism has been studied. The method has been successfully applied to the determina tion of ampicillin sodium in pharmaceutical, human plasma and urine samples. Analytical results obtained are satisfactory.

ChemInform Abstract: Conversion of Epoxides to Thiiranes Catalyzed with TiO(TFA)2 and TiCl3(OTf) in the Presence of Ammonium Thiocyanate or Thiourea.

Abstract TiO(CF3CO2)2 and TiCl3(CF3SO3) are efficient catalysts for the conversion of epoxides to thiiranes in the presence of ammoniun thiocyanate or thiourea under non-aqueous conditions.

Preparation of iron-deposited graphite surface for application as cathode material during electrochemical vat-dyeing process

Iron-deposited graphite surfaces were prepared, characterized and employed as cathode materials for electrochemical vat-dyeing process containing very low concentration of sodium dithionite. The electrodeposition, in presence of ammonium thiocyanate and gelatin or animal glue as binding additives, were found to give finer iron deposits for improved electrochemical dyeing application. The electrodeposits were characterized using scanning electron microscopy, electron-dispersive X-ray spectroscopy and X-ray diffraction methods, before and after electrochemical dyeing process. The electrochemical activity of the iron-deposited graphite electrodes always stored in water seems to depend on the surface-bound Fe 3+/Fe 2+ redox species. Vat dyes like C.I. Vat Violet 1, C.I. Vat Green 1 and C.I. Vat Blue 4 could be efficiently dyed employing these above electrode materials. The colour intensity and washing fastness of the dyed fabrics were found to be equal with conventionally dyed fabrics. The electrodes could also be reused for the dyeing process.

Indirect Determination of Sodium Cefotaxime with N‐Propyl Alcohol‐Ammonium Sulfate‐Water System by Extraction‐Flotation of Cuprous Thiocyanate

AbstractA novel method for the indirect determination of sodium cefotaxime by the extraction‐flotation of cuprous thiocyanate is described in this paper. The experiment indicated that the degradation of sodium cefotaxime took place in the presence of 0.20 M sodium hydroxide in a boiling water bath for 40 min. At pH 4.0, the thiol group (‐SH) of the degradation product of sodium cefotaxime could reduce Cu(II) to Cu(I) for the formation of the emulsion CuSCN precipitation in the presence of ammonium thiocyanate. By determining the residual amount of Cu(II) in the solution and calculating the flotation yield of CuSCN, the indirect determination of sodium cefotaxime can be achieved. When the concentration of Cu(II) was 5.0 μg mL−1, a good linear relationship was obtained between the flotation yield of CuSCN and the amount of sodium cefotaxime in the range of 0.50∼20 μg mL−1. The linear equation is E = 1.329 + 2.654C with a correlation coefficient r = 0.9988. The detection limit of sodium cefotaxime of this proposed method evaluated by calibration curve (3σ/k) was found to be 0.39 μg mL−1. Every parameter has been optimized and the reaction mechanism has been studied. This method has been successfully applied to the determination of sodium cefotaxime in pharmaceutical formulations, human serum, and urine samples, respectively. Analytical results obtained with this novel method are satisfactory.

Ultrasound-assisted thiocyanation of aromatic and heteroaromatic compounds using ammonium thiocyanate and DDQ

Thiocyanation of various aromatic and heteroaromatic compounds has been achieved in the presence of ammonium thiocyanate (NH4SCN) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in methanol solution under ultrasound irradiation. An ultrasonic probe of 24kHz frequency has been used for this study. Whereas the use of ultrasound increases the rate of reactions compared with reactions at reflux conditions, the electron-donor ability of aromatic nucleus enhances also the rate of reaction.

EQCM study of the electrodeposition of manganese in the presence of ammonium thiocyanate in chloride-based acidic solutions

The influence of ammonium thiocyanate (NH 4SCN) on the mechanism of manganese electrodeposition from a chloride-based acidic solution was investigated by cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM). The EQCM data were represented as plots dΔ m d t −1 versus E, known as massograms. Because massograms are not affected by interference from the hydrogen evolution reaction, they clearly show the manganese reduction and oxidation processes. By comparing the voltammograms with their corresponding massograms, it was possible to differentiate mass changes due to faradaic processes from those due to non-faradaic processes. Morphology, chemical composition and structure of the manganese deposits formed in different potential ranges were analyzed by scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), and X-ray diffraction (XRD). The results showed that in the absence of NH 4SCN, Mn(OH) 2(s) is formed in the potential range −1.1 to −0.9 V due to the hydrogen evolution reaction in this region. At more cathodic potentials, the deposition of β-manganese and the inclusion of Mn(OH) 2(s) into the deposit occur; both of these species underwent dissolution by non-faradaic processes during the anodic scan. In the presence of NH 4SCN, the formation of α- and γ-manganese was observed. When the potential was ≤−1.8 V and [NH 4SCN] exceeded 0.3 M, the α-manganese phase was favored.

MILD, EFFICIENT, AND CONVENIENT CONVERSION OF OXIRANES TO THIIRANES WITH AMMONIUM THIOCYANATE AND THIOUREA IN THE PRESENCE OF CERIUM(IV) POLYOXOMETALLATE

ABSTRACT Selective conversion of various oxiranes to the corresponding thiiranes in the presence of ammonium thiocyanate and thiourea can be effectively carried out by ammonium decatungestocerate(IV) icosahydrate, (NH4)8[CeW10O36]ċ20H2O.

Iron(III) 5,10,15,20-Tetrakis (pentafluorophenyl)-porphyrin as an Efficient Catalyst for Conversion of Epoxides to Thiiranes

Iron(III) 5,10,15,20-tetrakis(pentafluorophenyl) porphyrin, Fe(TF5PP)CI, is a new catalyst for the conversion of epoxides to the corresponding thiiranes in the presence of ammonium thiocyanate in excellent yields.

Comparison of physical chemical properties of llama V HH antibody fragments and mouse monoclonal antibodies

Antigen specific llama V HH antibody fragments were compared to antigen specific mouse monoclonal antibodies with respect to specificity, affinity and stability. The llama V HH antibody fragments and the mouse monoclonal antibodies investigated were shown to be highly specific for the protein antigen hCG or the hapten antigen RR-6. The affinity of the interaction between monovalent llama V HH antibody fragments and their antigen is close to the nanomolar range, similar to the bivalent mouse monoclonal antibodies studied. Llama V HH antibody fragments are similar to mouse monoclonal antibodies with respect to antigen binding in the presence of ammonium thiocyanate and ethanol. The results show that relative to antigen specific mouse monoclonal antibodies, antigen specific llama V HH fragments are extremely temperature stable. Two out of six llama V HHs are able to bind antigen specifically at temperatures as high as 90°C, whereas four out of four mouse monoclonal antibodies are not functional at this temperature. Together with the finding that llama V HH fragments can be produced at high yield in Saccharomyces cerevisiae, these findings indicate that in the near future antigen specific llama V HH fragments can be used in for antibodies unexpected products and processes.

Iron(III) 5,10,15,20-Tetrakis (pentafluorophenyl)porphyrin as an Efficient Catalyst for Conversion of Epoxides to Thiiranes

Iron(III) 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin, Fe(TF5PP)Cl, is a new catalyst for the conversion of epoxides to the corresponding thiiranes in the presence of ammonium thiocyanate in excellent yields.

Conversion of Epoxides to Thiiranes Catalyzed with TiO(TFA)2 and TiCl3(Otf) in the Presence of Ammonium Thiocyanate or Thiourea

TiO(CF3CO2)2 and TiCl3(CF3SO3) are efficient catalysts for the conversion of epoxides to thiiranes in the presence of ammoniun thiocyanate or thiourea under non-aqueous conditions.

Spectrophotometric study of diclofenac-Fe(III) complex

A multifactor optimisation technique is successfully applied to develop a new spectrophotometric method in which diclofenac sodium is analysed and determined as it's Fe(III) complex. The effect of simultaneously varying the pH, ionic strength and concentration of colour reagents in the reaction mixture were studied. A four-variable two-level factorial design was used to investigate the significance of each variable and interactions between them. A response surface design was used to optimise complex formation and extraction. It was established that diclofenac reacts with Fe(III) chloride, in the presence of ammonium thiocyanate, in the pH range 4.2–6.5, forming a red chloroform extractable (2:1) complex with maximum absorbance at 481 nm. By applying the methods of Sommer and Job involving non-equimolar solutions the conditional stability constant of the complex, at the optimum pH of 6.0 and an ionic strength μ = 0.19M, was found to be 10 6.4. Good agreement with Beer's law was found for diclofenac concentrations up to mmol l −1. The nominal percent recovery of diclofenac was 98.8% ( n = 10). The lower limit of sensitivity of the method was found to be 14.7 μg ml −1.

Stereospecific formation of S(−) styrene sulfide: Efficient conversion of epoxides to thiiranes catalysed with Ru(III)

Ru(III) catalysis the efficient conversion of different epoxides to their corresponding thiiranes in the presence of ammonium thiocyanate in exellent yields. Stereospecific conversion of R(+) styrene oxide to S(−) styrene sulfide was achieved in high optical purity.

ChemInform Abstract: Synthesis of 2‐Aroyliminopyrimido(3,2‐b)‐1,2,4‐thiadiazolines.

AbstractCoupling of the 2‐aminopyrimidines (I) with the aroyl chlorides (II) in the presence of ammonium thiocyanate (III) produces the aroylthioureas (IV) which undergo cyclization upon heating in phosphorus pentachloride and phosphorus oxychloride, forming the thiadiazolopyrimidines (V).