Chromyl chloride

Chromyl chloride
Wireframe model of chromyl chloride
Ball and stick model of chromyl chloride
Names
Preferred IUPAC name
Chromium(VI) dichloride dioxide
Systematic IUPAC name
Dichlorodioxochromium
Other names
Chromic acid chloride

Chromium oxychloride

Etard Reagent
Chlorochromic anhydride
Chromic oxychloride
Chromium chloride oxide
Chromium dioxide dichloride
Chromium dioxychloride
Chromium oxychloride
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.035.491
EC Number
  • 239-056-8
RTECS number
  • GB5775000
UNII
Properties
CrO2Cl2
Molar mass 154.9008 g/mol
Appearance blood red fuming liquid, similar to bromine
Odor musty, burning, acrid[1]
Density 1.911 g/mL, liquid
Melting point -96.5 °C
Boiling point 117 °C
Very soluble,hydrolysis
Vapor pressure 20 mmHg (20 °C)[1]
Hazards
Main hazards carcinogen, reacts violently with water[1]
GHS pictograms [2]
NFPA 704 (fire diamond)
Flash point noncombustible [1]
NIOSH (US health exposure limits):
PEL (Permissible)
 none[1]
REL (Recommended)
 Ca TWA 0.001 mg Cr(VI)/m3[1]
IDLH (Immediate danger)
 N.D.[1]
Related compounds
Related compounds
 SO2Cl2; VOCl3; MoO2Cl2; WO2Cl2; CrO2F2
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y verify (what is YN ?)
Infobox references

Nilered have a big shlong

Preparation

Chromyl chloride can be prepared by the reaction of potassium chromate or potassium dichromate with hydrogen chloride in the presence of sulfuric acid, followed by gentle distillation.[3][4]

K2Cr2O7 + 6 HCl → 2 CrO2Cl2 + 2 KCl + 3 H2O

The sulfuric acid serves as the dehydration agent. It can also be prepared directly by exposing chromium trioxide to anhydrous hydrogen chloride gas.

CrO3 + 2 HCl ⇌ CrO2Cl2 + H2O

The method used to prepare chromyl chloride is the basis for a qualitative test for chloride: a sample suspected of containing chloride is heated with a mixture of potassium dichromate and concentrated sulfuric acid. If chloride is present, chromyl chloride forms as evidenced by red fumes of CrO2Cl2. Analogous compounds are not formed with fluorides, bromides, iodides and cyanides.

Reagent for oxidation of alkenes

Chromyl chloride oxidizes internal alkenes to alpha-chloroketones or related derivatives.[5] It will also attack benzylic methyl groups to give aldehydes via the Étard reaction. Dichloromethane is a suitable solvent for these reactions.[6]

Safety considerations

CrO2Cl2 hydrolyzes to release hydrochloric acid (HCl) and hexavalent chromium (CrVI)

Acute: Exposure to chromyl chloride vapour irritates the respiratory system and severely irritates the eyes, and the liquid burns the skin and eyes. Ingestion would cause severe internal damage.[7]

Chronic: CrVI can produce chromosomal aberrations and is a human carcinogen via inhalation.[8] Frequent exposure of the skin to chromyl chloride may result in ulceration.[7]

gollark: That would be "very fast", yes.
gollark: I simply type very fast.
gollark: An alternative to using CD or USB images for installation is to use the static version of the package manager Pacman, from within another Linux-based operating system. The user can mount their newly formatted drive partition, and use pacstrap (or Pacman with the appropriate command-line switch) to install base and additional packages with the mountpoint of the destination device as the root for its operations. This method is useful when installing Arch Linux onto USB flash drives, or onto a temporarily mounted device which belongs to another system. Regardless of the selected installation type, further actions need to be taken before the new system is ready for use, most notably by installing a bootloader and configuring the new system with a system name, network connection, language settings, and graphical user interface. The installation images come packaged with an experimental command line installer, archinstall, which can assist with installing Arch Linux.
gollark: Arch is largely based on binary packages. Packages target x86-64 microprocessors to assist performance on modern hardware. A ports/ebuild-like system is also provided for automated source compilation, known as the Arch Build System. Arch Linux focuses on simplicity of design, meaning that the main focus involves creating an environment that is straightforward and relatively easy for the user to understand directly, rather than providing polished point-and-click style management tools — the package manager, for example, does not have an official graphical front-end. This is largely achieved by encouraging the use of succinctly commented, clean configuration files that are arranged for quick access and editing. This has earned it a reputation as a distribution for "advanced users" who are willing to use the command line. The Arch Linux website supplies ISO images that can be run from CD or USB. After a user partitions and formats their drive, a simple command line script (pacstrap) is used to install the base system. The installation of additional packages which are not part of the base system (for example, desktop environments), can be done with either pacstrap, or Pacman after booting (or chrooting) into the new installation.
gollark: On March 2021, Arch Linux developers were thinking of porting Arch Linux packages to x86_64-v3. x86-64-v3 roughly correlates to Intel Haswell era of processors.

References
  1. NIOSH Pocket Guide to Chemical Hazards. "#0142". National Institute for Occupational Safety and Health (NIOSH).
  3. Moody, B.J. (1965). "22". Comparative Inorganic Chemistry (1 ed.). London: Edward Arnold. p. 381. ISBN 0-7131-3679-0.
  4. Sisler, Harry H. (1946). "Chromyl Chloride [Chromium(VI) Dioxychloride]". Inorganic Syntheses. 2: 205–207. doi:10.1002/9780470132333.ch63.
  5. Freeman, Fillmore; DuBois, Richard H.; McLaughlin, Thomas G. (1971). "Aldehydes by Oxidation of Terminal Olefins with Chromyl Chloride: 2,4,4-Trimethylpentanal". Org. Synth. 51: 4. doi:10.15227/orgsyn.051.0004.
  6. F. Freeman (2004). "Chromyl Chloride". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rc177..}}
  7. Prof CH Gray, ed. (1966). "IV". Laboratory Handbook of Toxic Agents (2 ed.). London: Royal Institute of Chemistry. p. 79.
  8. IARC (1999-11-05) [1990]. Volume 49: Chromium, Nickel, and Welding (PDF). pp. 21–23. ISBN 92-832-1249-5. Archived from the original (PDF) on 2008-12-24. Retrieved 2008-03-26.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.