Nitrogen trichloride

Nitrogen trichloride. (NCl 3 ), also known as trichloroamine is a pungent-smelling, oily, yellow colored liquid most commonly found as a by-product of chemical reactions between ammonia derivatives and chlorine.

Summary

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  • 1 Properties
    • 1 Solid Phase
    • 2 Liquid phase
    • 3 Gas phase
  • 2 Obtaining
  • 3 Applications
  • 4 Reactions
  • 5 Pollutant gas
  • 6 Effects on humans
    • 1 Higher risks
  • 7 Sources

Properties

  • Gas properties:
  • Molecular Weight: 71,019 g / mol

Solid phase

Melting point: -206.69 o C Latent heat of fusion (1,013 bar, at the melting point): 5,603 kJ / kg

Liquid phase

  • Liquid density (1,013 bar at boiling point): 1,537,863 kg / m 3
  • Liquid / Gas Equivalent (1,013 bar and 15 oC (59 o F)): 510.1 vol / vol
  • Boiling point (1,013 bar): -129.01 oC
  • Latent heat of vaporization (1,013 bar at boiling point): 162,708 kJ / kg
  • Critical point
    • Critical Temperature: -39.15 oC
    • Critical Pressure: 44.61 bar
    • Critical Density: 562.47 kg / m3
  • Triple point
    • Triple point temperature: -206.69 oC
    • Triple point pressure: 1.854E-06 bar

Gas phase

  • Gas density (1,013 bar y 0 oC (32 o F)): 6.2404 kg / m 3
  • Gas density (1,013 bar y 15 oC (59 o F)): 3.0158 kg / m 3
  • Compressibility factor (Z) (1,013 bar y 15 oC (59 o F)): 0.99594
  • Specific gravity (air = 1): 2.46
  • Specific Volume (1,013 bar and 21 oC (70 o F)): 0.3432 m 3 / kg
  • Constant pressure heat capacity (Cp) (1 bar and 25 oC (77 o F)): 0.0536 kJ / (mol.K)
  • Constant pressure heat capacity (Cp) (1,013 bar and 15.6 oC (60 o F)): 0.0451 kJ / (mol.K)
  • Specific heat ratio (Range: Cp / Cv) (1,013 bar and 15.6 oC (60 ° F)): 1.1876
  • Viscosity (1,013 bar and 0 oC (32 o F)): 1.8123E-04 Poise
  • Thermal Conductivity (1,013 bar and 0 oC (32 o F)): 16,023 mW / (mK)
  • Miscellaneous
    • Solubility in water (20 oC and 1 bar): 0.021 vol / vol

Obtaining

The compound is prepared by treating ammonium salts, such as ammonium nitrate with chlorine: 4 NH 3 + 3 Cl 2 = NCl 3 + 3 NH 4 Cl

The intermediates of this conversion include chloramines and dichloramine, NH 2 Cl and NHCl 2 , respectively. Like ammonia, NCl 3 is a pyramid molecule. The N-Cl distances are 1.76 and the Cl-N-Cl angles are 107. It is a rare example of a binary compound that cannot be prepared directly from the elements (ie Nitrogen does not react with Fluorine) .

Almost all the other elements on the periodic table react directly, often violently, with fluorine.

After the first attempt at synthesis in 1903 , Otto Ruff produced 25 years later, nitrogen trifluoride by electrolysis of a molten mixture of ammonium fluoride and hydrogen fluoride . This turned out to be much less reactive than nitrogen trichloride. Today, it is arranged both by the direct reaction of ammonia and fluorine and by a variation of the Ruff method. It comes in pressure bottles.

Applications

Nitrogen trifluoride is used in the plasma engraving of silicon wafers. Prevailing work is being done on cleaning the PECVD chambers in the high-volume production of thin-film and liquid crystal displays based on silicon solar cells. It can also be used with tungsten silicide and tungsten produced by cardiovascular diseases. NF3 has been considered as an environmentally preferable substitute for sulfur hexafluoride or perfluorocarbons such as hexafluoroethane .

Nitrogen trifluoride is also used in deuterium and hydrogen fluoride lasers , which are the types of chemical lasers.

Reactions

Despite the similarities of the Pauling electronegativities of nitrogen and chlorine, this molecule is highly polar with negative charges residing on nitrogen. So the nitrogen in NCl3 is often considered to have the oxidation state of -3 and the chlorine atoms are considered to be in the oxidation state of 1. Most of its reactivity is consistent with this description. Hydrolyzes with hot water to release ammonia and hypochlorous acid. NCl 3 + 3 H 2 O? NH3 + 3 HOCl

Polluting gas

Nitrogen trifluoride is a greenhouse gas with an extremely high global warming potential (it has a GWP index 17,200 times higher than that of carbon dioxide (CO 2 ) compared to more than one year in period 100). Its global warming potential is second only to sulfur hexafluoride .

Effects on humans

Nitrogen trichloride can irritate mucous membranes, it is tear gas , but has never been used as such. The pure substance is a dangerous explosive, being sensitive to light, heat, even moderate shock and organic compounds. Pierre Louis Dulong in 1812 lost two fingers and one eye in two explosions. An NCl 3 explosion temporarily blinded Sir Humphry Davy , prompting him to hire Michael Faraday as a co-worker.

In 2006 , Belgian researchers reported a possible relationship between NCl 3 and the increased number of childhood asthma cases, in what they call the pool chlorine hypothesis, as an alternative to the hygiene hypothesis with a closer causal link.

It is a lung irritant with toxicity comparable to nitrogen oxides, and overexposure by inhalation causes the conversion of hemoglobin in the blood to methemoglobin , which can lead to the condition of methemoglobinemia .

Greater risks

Inhalation, Skin Contact and Reactivity

 

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