Sodium Cyanate
Names
Other names
Cyansan, Sodium Cyanate, Cyanic Acid Sodium Salt, Isocyanate
Identifiers
UNII
  • InChI=1S/CHNO.Na/c2-1-3;/h3H;/q;+1/p-1
Properties
CNNaO
Molar mass 65.01 g/mol
Appearance white powder
Density 2.108 g/cm3
Boiling point 550°C
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
May cause irritation to skin, digestive tract, and respiratory tract.
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Sodium Cyanate (CNNaO) is a salt that is white in color and odorless. It is primarily used as a reagent for research purposes, however it is not limited to experimental use. This compound is used in pharmaceuticals, photographic initiators, heat treatment for metals, and in many insecticides [1]. Sodium cyanate is used in fertilizer to kill weeds because it contains a high volume of nitrogen. A lot of research and experiments have been performed dealing with sodium cyanate. Scientists have done experiments to see if sodium cyanate has any relation to the treatment of cancer. However, there has not been a human-safe form of treatment using sodium cyanate. Sodium cyanate has only been tested on animals even though there has been evidence that this compound is an effective cancer inhibitor. The toxicity of sodium cyanate is unknown so it is unsafe for human practice.

Synthesis

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main article:The Preparation of Pure Sodium Cyanate from Urea


Sodium cyanate can be made via a variety of different compounds, a main one being synthesized by the isomerization of urea. There are two forms of sodium cyanate: one which contain various impurities (which is not suitable for biological use) and one with less impurities that make it a good biological reagent.

Preparation via Silver Cyanate
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This method of preparation involved the reaction between a heated, aqueous solution of urea and silver nitrate. This reaction yielded a precipitate of about 80% AgCNO and about 20% AgCo3. To further with the reaction to obtain sodium cyanate, Walker and Hambly (founders of the mechanism), added NH4Cl to the aqueous suspension to produce NH4CNO. When NaCl was used in excess in place of NH4Cl, the reaction with AgCNO; this would obtain the NaCNO in the aqueous solution and AgCl would precipitate. The NaCNO would be isolated at a pH between 6.0-6.5 because NaCNO is stable at pH of 5.0 or greater. If the pH were less than 5.0, NaCNO would hydrolyze and would not be isolated.

Preparation from Urea under Anhydrous Conditions
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Isomerisation of urea under anhydrous conditions yielded sodium cyanate. This was modified from the previous knowledge that sodium cyanate was produced from the isomerisation of urea under high temperature conditions. NaOH was boiled with urea to yield 75% NaCNO and about 25% Na2CO3. These impurities were due to the equivalent of water that was still left in the solution.


Water under the high temperatures used in this experiment is expected to boil, causing NaCNO to hydrolyze into sodium carbonate, ammonia, and carbon dioxide. To prevent this, dry butanol with sodium butoxide in equal amounts in relation to urea. NaCNO is isolated from the reaction.


Occurrences

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Although sodium cyanate is not commonly found in nature; however, the compound is seen as a product of the oxidation of sodium cyanide. Sodium can then be purified and used in a number of different ways, including a reactant in the synthesis of various products and as a testing chemical in experiments. (see Uses )

Uses

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Sodium cyanate is most commonly seen as a herbicide or insecticide to control the weed and insect population. It acts as the active ingredient in the herbicide to kill the weeds, but the high nitrogen concentration of sodium cyanate doubles the herbicide as a fertilizer. However, according to the Texas Department of Agriculture [2], the use of herbicides containing sodium cyanate must be limited when it is being used for livestock predation prevention.

In addition to herbacides, sodium cyanate can be seen in a number of different reactions. Sodium cyanate is the intermediate in the production of raw materials, such as BPMC, carbofuran and methomyl (carbamate chemicals for agriculture), as well as in the production of various dyes. There are also organic reactions that can take place with the use of sodium cyanate, like adding to amines to form urea derivatives. Some metals undergo heat treatment that require a sensitizer and a salt; often times, this sodium cyanate is used as this catalytic substance. [3]

Sodium cyanate is also commonly seen in various medical researches, many that deal with cancer and how it functions as an inhibitor to these cells. Although there has been positive evidence that sodium cyanate is a qualified protein inhibitor in cancer cell growth, there is no justification that it is safe for human use. All experiments have been tested on animals or voluntary human cell donors (in which these cells are tested in vitro. Other experiments have found that sodium cyanate is a hypothetical diuretic. This was also tested in animal (rats). In addition, sodium cyanate was used to test the effects and of sickle-cell disease and to further study hypoxia.

Experiments

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Sickle Cell Anemia

Sodium Cyanate has been found to be useful in treating sickle cell anemia. Sodium cyanate can be purified and it possesses certain chemical properties that pertain to studies/ clinical trials done on sickle cell anemia. Sodium cyanate can break down into ammonia and sodium bicarbonate, sodium bicarbonate being the one that is detected after sodium cyanate is purified. The way to increase the reaction of cyanate and water is to increase the concentration of it, decrease the pH of the solution, or to increase the temperature of the system. To sterilize sodium cyanate, one should use dry heat. Sodium cyanate is stable compared to the aqueous solution under multiple conditions, like concentration, time, and temperature (these are the conditions that erythrocytes are exposed to in the clinical experiments).

An example of an experiment that was done was when samples of blood were taken from patients who suffered from sickle cell anemia. The blood was pre-incubated with sodium cyanate to observe the effect it had on the sample. From the results of this experiment, sodium cyanate had a similar effect on total protein synthesis in red blood cells from patients with sickle cell anemia, sickle-beta thalassemia, and homozygous beta thalassemia. It was discovered that sodium cyanate has various effects on the red blood cells, which can be due to the increased affinity for oxygen and higher proportion of oxyhemoglobin that can occur with carbamylation instead of a direct inhibition of sickling.[4]

Cancer Treatment

Sodium Cyanate has been shown to inhibit chemical carcinogens in neoplasia with 7, 12-dimethyl-benz(a)anthracene and 1,2-dimethyldrazing (carcinogens) induced tissues under metabolic activation; because of this characteristic, sodium cyanate has been tested for possible cancer treatment. Under an experiment conducted by Lee W. Wattenberg, two subjects were fed with sodium cyanate: DMH-induced neoplasia of large intestine of mouse and DMBA-induced mammary neoplasia in rat, in addition to sampling rats who were raised the same but were not given any sodium cyanate. Although it was shown that sodium cyanate produced low toxicity levels in animals, it possessed some effects in humans that would not be deemed useful for human use. At the end of the experiment, tumor counts were done through autopsy and recorded. Overall, the sodium cyanate fed subjects possessed less tumors than those who were not treated with sodium cyanate. [5]

Hypoxia

Sodium cyanate has been used as a mild chemical toxin to study hypoxia. It is thought to increase the hypoxia tolerance of animals as it increases the affinity of hemoglobin to oxygen. In many of our tissues there are channels called large conductance calcium-activated potassium channels. They play a huge part in regulating the neuronal excitability, cell volume and excitation-contraction coupling. The reduction of oxygen tension has been shown to induce inhibition of these large conductance calcium activated potassium channels in cells from the carotid body, pulmonary smooth muscle, and adrenal glands. A study was conducted to see if sodium cyanate could affect calcium-activated potassium current in hippocampal neuron-derived H19-7 cells. The results of the study showed that during cell exposure to sodium cyanate, activation of the large conductance calcium-activated potassium channels in neurons could be one ionic mechanism that is the cause of decreased neuronal excitability and neurological disorders.[6]

References

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  • "Sodium Cyanate CAS No. 917-61-3." Sparchem. N.p., 1 Dec. 2004. Web. 6 Mar. 2013. <: Cyansan, Sodium Cyanate, Cyanic Acid Sodium Salt, Isocyanate>.
  • "Sodium Cyanate CAS No. 917-61-3." Sparchem. N.p., 1 Dec. 2004. Web. 1 Mar. 2013. <: Cyansan, Sodium Cyanate, Cyanic Acid Sodium Salt, Isocyanate>.