• Toxicological Research
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• v.29 no.2
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• pp.143-147
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• 2013

Cyanogenic glycosides are HCN-producing phytotoxins; HCN is a powerful and a rapidly acting poison. It is not difficult to find plants containing these compounds in the food supply and/or in medicinal herb collections. The objective of this study was to investigate the distribution of total cyanide in nine genera (Dolichos, Ginkgo, Hordeum, Linum, Phaseolus, Prunus, Phyllostachys, Phytolacca, and Portulaca) of edible plants and the effect of the processing on cyanide concentration. Total cyanide content was measured by ion chromatography following acid hydrolysis and distillation. Kernels of Prunus genus are used medicinally, but they possess the highest level of total cyanide of up to 2259.81 $CN^-$/g dry weight. Trace amounts of cyanogenic compounds were detected in foodstuffs such as mungbeans and bamboo shoots. Currently, except for the WHO guideline for cassava, there is no global standard for the allowed amount of cyanogenic compounds in foodstuffs. However, our data emphasize the need for the guidelines if plants containing cyanogenic glycosidesare to be developed as dietary supplements.

• Journal of the Korean Applied Science and Technology
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• v.6 no.2
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• pp.29-37
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• 1989

Using the quarternary ammonium salts as phase transfer catalyst, the nucleophilic substitution reaction of 1-chlorooctane with sodium-cyanide was investigate kinetically with respect to the formation of octanenitrile. The product was analyzed with gas chromatograph, and quantity of octanenitrile was measured. The reaction condition was considered by the effect of the reaction temperature, of the species and the amount of catalyst, of the speed of strirring, and of the concentration of reactants. The reaction was carried out in the first order on the concentration of 1-chlorooctane and sodium cyanide, respectively. The over-all order was 2nd. The activation energies for the nucleophilic substitution reaction of 1-chlorooctane and 1-bromooctane under tetrabutylammonium hydrogen-sulfate were calculated as 2.05 and 10.08kcal/mol, respectively. The effect of various caltalysts was decreased in the order of tetrabutylammonium bromide, terabutylammonium, tetrabutylammonium hydrogensulfate, and tetrabutylammonium iodide. The reaction rate was dependent on the concentration of sodium-cyanide dissolved in the aqueous phase, and the good result was shown when the mol ratio between 1-chlorooctane and sodium cyanide was one per three.

• Journal of Microbiology and Biotechnology
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• v.26 no.12
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• pp.2179-2183
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• 2016

Nitrilases pose attractive alternatives to the chemical hydrolysis of nitrile compounds. The activity of bacterial nitrilases towards substrate is intimately tied to the formation of large spiral-shaped oligomers. In the nitrilase CynD (cyanide dihydratase) from Bacillus pumilus, mutations in a predicted oligomeric surface region altered its oligomerization and reduced its activity. One mutant, CynD Y70C, retained uniform oligomer formation however it was inactive, unlike all other inactive mutants throughout that region all of which significantly perturbed oligomer formation. It was hypothesized that Y70 is playing an additional role necessary for CynD activity beyond influencing oligomerization. Here, we performed saturation mutagenesis at residue 70 and demonstrated that only tyrosine or phenylalanine is permissible for CynD activity. Furthermore, we show that other residues at this position are not only inactive, but have altered or disrupted oligomer conformations. These results suggest that Y70's essential role in activity is independent of its role in the formation of the spiral oligomer.

• Analytical Science and Technology
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• v.6 no.1
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• pp.47-55
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• 1993

The quantitative determination of trace cyanide ion in the presence of sulfide ion has been studied by addition of cupric ion using differential pulse Cathodic Stripping Voltammetry. The detection limit of cyanide ion in the presence of $5.0*10^{-5}M$ sulfide ion and $1.0*10^{-3}M$ cupric ion was $2.0*10^{-7}M$ in KCI-Phosphate buffer(pH=7.0) at accumulation potential -0.30V and accumulation time 3.0 min.

• Journal of the Korean Chemical Society
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• v.17 no.6
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• pp.411-415
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• 1973

The reaction between cyanide ion and triphenyl methane dyes is subject to marked catalysis by cationic micelles of cetyltrimethyl ammonium bromide(CTABr) and retarded by anionic micelles of sodium lauryl sulfate(NaLS). Added salts, anions inhibit the catalysis by CTABr, and cations, especially $Zn^{++},\;Cd^{++}$ decrease the retardation of the reaction rates in the presence of NaLS. The kinetic effects of the ionic micelles are much larger in water than in ethanol-water, methanol-water, propanol-water and acetone-water, but strange solvent effects, acceleration the reaction rates, was found in the reaction with malachite green in water-methanol system.

• Corrosion Science and Technology
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• v.21 no.2
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• pp.89-99
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• 2022

A versatile method for performing non-cyanide electroless gold plating using thiomalic acid (TMA) as a complexing agent and 2-aminoethanethiol (AET) as a reducing agent was investigated. It was found that TMA was an excellent complexing agent for gold. It can be used in electroless gold plating baths at a neutral pH with a high solution stability, makes it a potential candidate to replace conventional toxic cyanide complex. It was found that one gold atomic ion could bind to two TMA molecules to form the [2TMA-Au⁺] complex in a solution. AET can be used as a reducing agent in electroless gold plating solutions. The highest current density was obtained at electrode rotation rate of 250 to 500 rpm based on anodic and cathodic polarization curves with the mixed potential theory. Increasing AET concentration, pH, and temperature significantly increased the anodic polarization current density and shifted the plating potential toward a more negative value. The optimal gold ion concentration to obtain the highest current density was 0.01 M. The cathodic current was higher at a lower pH and a higher temperature. The current density was inversely proportional to TMA concentration.

• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1675-1680
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• 2012

Three new cyanide-bridged $Cr^{III}Mn^{II}$ binuclear complexes, $[Mn(phen)_2Cl][Cr(bpmb)(CN)_2]{\cdot}H_2O$ ($\mathbf{1}$) (phen = 1,10-phenanthroline, $bpdmb^{2-}$ = 1,2-bis(pyridine-2-carboxamido)-4-methyl-benzenate), $[Mn(phen)_2Cl][Cr(bpmb)-(CN)_2]{\cdot}H_2O$ ($\mathbf{2}$) ($bpdmb^{2-}$ = 1,2-bis(pyridine-2-carboxamido)-4,5-dimethyl-benzenate), and $[Mn(phen)_2Cl]-[Cr(bpClb)(CN)_2]{\cdot}CH_3OH{\cdot}H_2O$ ($\mathbf{3}$) ($bpClb^{2-}$ = 1,2-bis(pyridine-2-carboxamido)-4-chloro-benzenate) were obtained based on $Mn(phen)_2Cl_2$ and a series of dicyanidechromate(III) building blocks. Single crystal X-ray diffraction analysis shows the structures of the three complexes are dimeric type with two different metal centers linked by a cyanide group from corresponding dicyanidechromate(III) building block. Magnetic investigations indicate the existence of relatively weak antiferromagnetic coupling between Cr(III) and Mn(II) ions with best-fit constants $J_{CrMn}=-2.78(5)cm^{-1}$ for $\mathbf{1}$, $J_{CrMn}=-3.02(2)cm^{-1}$ for $\mathbf{2}$ and $J_{CrMn}=-2.27(3)cm^{-1}$ for $\mathbf{3}$ based on the spin exchange Hamiltonian = $-2J_{CrMn}\hat{S}_{Cr}\hat{S}_{Mn}$. The magneto-structural correlation of cyanide-bridged $Cr^{III}Mn^{II}$ complexes has been discussed at last.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.337-341
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• 2001

A new method to extract gold from pyrite roster cinder, which combines ultra-fine-grinding with resin-in-pulp, has been studied in this paper. Compared with traditional leaching technology, it can short leaching time, avoid complex filter process, lower sodium cyanide consumption and increase gold recovery by 35%. During leaching, aluminium oxide ball was used as stirred medium, hydrogen peroxide as leaching aid and sodium hexametaphosphate as grinding aid. With the high efficiency and chemistry effect of ultra-fine-grinding, the leaching process was developed and the gold leaching rate may reach 88%. With AM-2 Б resin as abosorber and sulfocarbamide (TU) as eluent, gold was recovered from cyanide pulp by resin-in-pulp. AM-2 Б resin has good adsorbability in cyanide solution(pH=10). It was easy to elude gold from the loaded resin with 0.1㏖/L cholhydric acid and 1㏖/L sulfocabamide. The effect of contact time, temperature and acidity etc. on the gold absorption had been examined with static methods. The results showed that the adsorption and desorption of gold could both reach over 98%. The effects of flow rate of solution on dynamic adsorption and elution of gold had been examined with dynamic methods. Breakthrough curve and elution curve had been drawn in this paper. A mild condition was determined through a number of experiments: leaching time 2 hours, liquid solid ratio 4:1, sodium cyanide 3kg/t, hydrogen peroxide 0.05%, sodium hexametaphosphate 0.05%; adsorption time 30 minutes, temperature 10-3$0^{\circ}C$, resin($m\ell$) solid(g) ratio 1:10, eluent resin ratio 10-20:1, velocity of eluent $1.5m\ell$/min. Under the mild condition, the gold recovery may reach 85%.

• Journal of the Korean Chemical Society
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• v.9 no.2
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• pp.67-70
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• 1965

Polarographic studies of reduction of Ni(Ⅱ)-CN complex on Hg-electrode have indicated that $Ni(CN)_4^{2-}$ is reduced by two paths, via one electron process Ni(CN)42- + e [1]↔[2] Ni(CN)43- =(eq) Ni(CN)2- + 2CN- and via two electron process Ni(CN)42- + 2e [3]→ 1/2[Ni(CN)33-]2 + CN- of which reduction [1] must be faster than reduction [3]. At very dilute cyanide concentration (0.004 to 0.01 M) cathodic wave is practically responsible for reaction [1] and two cyanide ions appear to contribute to the reaction. As increasing cyanide ion concentration the rate of oxidation reaction [2] catalysed by Hg increases and reaction [1] and [2] approach to equilibrium. Therefore, reaction [3] represents the cathodic wave at high concentration of cyanide (above 0.2 M). This mechanism can also explain the fact that limiting current at $[CN^-]$ = 8 M is approximately twice of that at 0.004 M CN.

• Journal of Environmental Science International
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• v.17 no.12
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• pp.1343-1351
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• 2008

The activated sludge obtained from wastewater coke oven plant was immobilized by entrapment with polyethylene glycol (PEG). The effects of several factors on the biodegradation of $CN^-$ from. synthetic wastewater were investigated using batch and continuous reactors. The degradation rate of $CN^-$ increased with increasing of the immobilized bead volume in the reactor. Approximately 7.65mg/L of $NH_4-N$ was produced upon the degradation of 35mg/L of $CN^-$. When high concentrations of the toxic cyanide complex were used in the testing of cyanide degradation, the free activated sludge could be inhibited more than that of the immobilized activated sludge. When the phenol concentration was higher than 400mg/L in the synthetic wastewater, approximately 98.4% of $CN^-$ was removed within 42 hours by the immobilized activated sludge. However, the cyanide was not completely degraded by the tree activated sludge. This indicates that high phenol concentrations can act as a toxic factor for the free activated sludge. A $CN^-$ concentration of less than 1mg/L was achieved by the immobilized sludge at the loading rate of 0.025kg $CN^-/m^3-d$. Moreover, it was found that the HRT should be kept for 48 hours in order to obtain stable treatment conditions.