| Revision as of 15:56, 7 August 2011 editCheMoBot (talk | contribs)Bots141,565 edits Updating {{chembox}} (no changed fields - added verified revid - updated 'DrugBank_Ref', 'UNII_Ref', 'ChEMBL_Ref', 'ChEBI_Ref', 'KEGG_Ref', 'StdInChI_Ref', 'StdInChIKey_Ref') per [[Misplaced Pages:WikiProject Chemicals/Chembox validation|Chem/Drugbox valid← Previous edit |
Latest revision as of 11:10, 24 December 2024 edit undoGrendelNightmares (talk | contribs)Extended confirmed users685 edits →Safety considerations: Added mention that CrO2Cl2 is a carcinogenTags: Mobile edit Mobile app edit Android app edit App section source |
| (170 intermediate revisions by more than 100 users not shown) |
| Line 1: |
Line 1: |
|
{{Chembox |
|
{{Chembox |
|
|
| Watchedfields = changed |
|
| verifiedrevid = 443522508 |
|
|
|
| verifiedrevid = 443523900 |
|
| ImageFileL1 = Chromyl-chloride-2D.png |
|
|
| ImageNameL1 = Wireframe model of chromyl chloride |
|
| ImageFileL1 = Chromyl-chloride-2D.png |
|
|
| ImageNameL1 = Wireframe model of chromyl chloride |
|
| ImageFileR1 = Chromyl-chloride-3D-balls.png |
|
|
|
| ImageFileR1 = Chromyl-chloride-3D-balls.png |
|
| ImageNameR1 = Ball and stick model of chromyl chloride |
|
|
| ImageFile2 = Chromyl chloride.jpg |
|
| ImageNameR1 = Ball and stick model of chromyl chloride |
|
| ImageName2 = Chromyl chloride in vial |
|
| ImageFile2 = Chromyl chloride.jpg |
|
|
| ImageName2 = Chromyl chloride in vial |
|
| PIN = Chromium(VI) dichloride dioxide |
|
|
|
| PIN = Chromium(VI) dichloride dioxide |
|
| SystematicName = Dichlorodioxochromium |
|
|
|
| SystematicName = Dichloridodioxidochromium |
|
| OtherNames = Chromic acid chloride<br /> |
|
|
|
| OtherNames = Chromic acid chloride<br /> |
|
Chromium oxychloride<br /> |
|
Chromium oxychloride<br /> |
|
|
Etard Reagent<br/> Chlorochromic anhydride<br/> Chromic oxychloride<br/> Chromium chloride oxide<br/> Chromium dioxide dichloride<br/>Chromium dioxychloride<br/> Chromium oxychloride |
|
Etard Reagent |
|
|
| Section1 = {{Chembox Identifiers |
|
| Section1 = {{Chembox Identifiers |
|
| InChI1 = 1/2ClH.Cr.2O/h2*1H;;;/q;;+2;;/p-2/rCl2CrO2/c1-3(2,4)5 |
|
|InChI1 = 1/2ClH.Cr.2O/h2*1H;;;/q;;+2;;/p-2/rCl2CrO2/c1-3(2,4)5 |
|
| InChIKey1 = AHXGRMIPHCAXFP-GRYJOLFGAD |
|
|InChIKey1 = AHXGRMIPHCAXFP-GRYJOLFGAD |
|
|
|CASNo_Ref = {{cascite|correct|??}} |
|
| CASNo = 14977-61-8 |
|
|
|
|CASNo = 14977-61-8 |
|
| PubChem = 22150757 |
|
|
|
|Gmelin = 2231 |
|
| PubChem_Ref = {{Pubchemcite}} |
|
|
|
|UNII_Ref = {{fdacite|correct|FDA}} |
|
| ChemSpiderID = 21106426 |
|
|
|
|UNII = JQU316FZ5W |
|
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
|
|
|
|UNNumber = 1758 |
|
| EINECS = 239-056-8 |
|
|
|
|PubChem = 22150757 |
|
| RTECS = GB5775000 |
|
|
|
|ChemSpiderID = 21106426 |
|
| ChEBI_Ref = {{ebicite|correct|EBI}} |
|
|
|
|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
|
| ChEBI = 33038 |
|
|
|
|EINECS = 239-056-8 |
|
| StdInChI_Ref = {{stdinchicite|correct|chemspider}} |
|
|
|
|RTECS = GB5775000 |
|
| StdInChI = 1S/2ClH.Cr.2O/h2*1H;;;/q;;+2;;/p-2 |
|
|
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} |
|
|ChEBI_Ref = {{ebicite|correct|EBI}} |
|
|
|ChEBI = 33038 |
|
| StdInChIKey = AHXGRMIPHCAXFP-UHFFFAOYSA-L |
|
|
|
|StdInChI_Ref = {{stdinchicite|correct|chemspider}} |
|
| SMILES = Cl(Cl)(=O)=O |
|
|
| InChI = 1S/2ClH.Cr.2O/h2*1H;;;/q;;+2;;/p-2 |
|
|StdInChI = 1S/2ClH.Cr.2O/h2*1H;;;/q;;+2;;/p-2 |
|
|
|StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} |
|
| InChIKey = AHXGRMIPHCAXFP-UHFFFAOYSA-L}} |
|
|
|
|StdInChIKey = AHXGRMIPHCAXFP-UHFFFAOYSA-L |
|
| Section2 = {{Chembox Properties |
|
|
|
|SMILES = Cl(Cl)(=O)=O |
|
| Formula = CrO<sub>2</sub>Cl<sub>2</sub> |
|
|
|
|InChI = 1S/2ClH.Cr.2O/h2*1H;;;/q;;+2;;/p-2 |
|
| MolarMass = 154.9008 g/mol |
|
|
|
|InChIKey = AHXGRMIPHCAXFP-UHFFFAOYSA-L}} |
|
| Appearance = deep red fuming liquid |
|
|
|
| Section2 = {{Chembox Properties |
|
| Density = 1.911 g/mL, liquid |
|
|
|
|Formula = CrO<sub>2</sub>Cl<sub>2</sub> |
|
| MeltingPt = -96.5 °C |
|
|
|
|MolarMass = 154.9008 g/mol |
|
| BoilingPt = 117 °C |
|
|
|
|Appearance = Blood-red fuming liquid, similar to ] |
|
| Solubility = Decomposes |
|
|
|
|Odor = Musty, burning, acrid<ref name=PGCH/> |
|
}} |
|
|
|
|Density = 1.911 g/mL, liquid |
|
| Section3 = {{Chembox Hazards |
|
|
|
|MeltingPtC = -96.5 |
|
| MainHazards = |
|
|
|
|BoilingPtC = 118.5 |
|
| FlashPt = |
|
|
|
|Solubility = Reacts with water |
|
| Autoignition = |
|
|
|
|VaporPressure = 20 mmHg (20 °C)<ref name=PGCH/> |
|
| RPhrases = {{R49}} {{R46}} {{R8}} {{R35}} {{R43}} {{R50/53}} |
|
|
|
}} |
|
| SPhrases = {{S53}} {{S45}} {{S60}} {{S61}} |
|
|
|
| Section3 = {{Chembox Hazards |
|
}} |
|
|
|
|ExternalSDS = |
|
| Section8 = {{Chembox Related |
|
|
|
|GHSPictograms = {{GHS03}}{{GHS05}}{{GHS07}}{{GHS08}}{{GHS09}} |
|
| OtherCpds = ]; ]; MoO<sub>2</sub>Cl<sub>2</sub>; ]; ]}} |
|
|
|
|MainHazards = Toxic, oxidizer, carcinogenic, mutagenic, reacts violently with water<ref name=PGCH/> |
|
|
|FlashPt = noncombustible |
|
|
|FlashPt_ref = <ref name=PGCH/> |
|
|
|GHSSignalWord = Danger |
|
|
|HPhrases = {{H-phrases|271|314|317|340|350|410}} |
|
|
|PPhrases = {{P-phrases|201|210|280|303+361+353|305+351+338+310|308+313}}<ref>{{cite web |title=Chromyl chloride 200042 |url=https://www.sigmaaldrich.com/catalog/product/aldrich/200042?lang=en®ion=GB |website=Sigma-Aldrich |archive-url=https://archive.org/download/chromyl-chloride-msds/Chromyl%20chloride%20MSDS.pdf |archive-date=2020-09-01}}</ref> |
|
|
|NFPA-H = 3 |
|
|
|NFPA-F = 0 |
|
|
|NFPA-R = 2 |
|
|
|NFPA-S = W+OX |
|
|
|PEL = none<ref name=PGCH>{{PGCH|0142}}</ref> |
|
|
|IDLH = N.D.<ref name=PGCH/> |
|
|
|REL = Ca TWA 0.001 mg Cr(VI)/m<sup>3</sup><ref name=PGCH/> |
|
|
}} |
|
|
| Section4 = {{Chembox Related |
|
|
|OtherCompounds = ]<br />]<br />MoO<sub>2</sub>Cl<sub>2</sub><br />]<br />]}} |
|
}} |
|
}} |
|
'''Chromyl chloride''' is a chemical compound with the formula CrO<sub>2</sub>Cl<sub>2</sub>. This compound is an opaque dark blood-red liquid at room temperature and pressure. It is tetrahedral, somewhat like ]. CrO<sub>2</sub>Cl<sub>2</sub> is similar to the most commonly encountered chromium(VI) derivative ], <sup>2−</sup>; both are tetrahedral Cr(VI) compounds. However, they differ in both oxidizing power and in physical properties: one is a liquid and the other forms salts. |
|
|
|
|
|
CrO<sub>2</sub>Cl<sub>2</sub> is a neutral molecular species. This means that in the liquid and solid forms, the individual CrO<sub>2</sub>Cl<sub>2</sub> entities interact purely via ]. Such weak bonding leads to low melting and boiling points, which is related to the fact that it is a distillable liquid. |
|
|
|
|
|
|
|
'''Chromyl chloride''' is an ] with the formula CrO<sub>2</sub>Cl<sub>2</sub>. It is a reddish brown compound that is a volatile liquid at room temperature, which is unusual for transition metal compounds. It is the dichloride of ]. |
|
The diminished oxidizing power of <sup>2−</sup> vs. CrO<sub>2</sub>Cl<sub>2</sub> can be ascribed to its anionic nature, which diminishes its electron affinity. Also, chloride is a poorer pi-donor ligand than is oxide. |
|
|
|
|
|
|
==Preparation== |
|
==Preparation== |
|
CrO<sub>2</sub>Cl<sub>2</sub> is prepared by the action of HCl on ], or the reaction with ] with concentrated HCl, followed by ] as a dehydrating agent. The heavy CrO<sub>2</sub>Cl<sub>2</sub> separates as an immiscible, dense liquid. It then can be separated using a separatory funnel or by simple distillation, which is normally performed.<ref>Sisler, H. H. "Chromyl Chloride" Inorganic Synthesis McGraw-Hill: New York, 1946; Vol. 2, pp 205–207.</ref> CrO<sub>2</sub>Cl<sub>2</sub> can also be prepared using other chlorinating agents such as ] and ], or by addition of concentrated sulphuric acid to an intimate mixture of ] and ], followed by gentle distillation.<ref>{{cite book |last= Moody |first= B.J. |title= Comparative Inorganic Chemistry |edition= 1 |publisher= Edward Arnold |location= London |chapter= 22 |page= 381 |year= 1965 |isbn= 0713136790 }}</ref> |
|
Chromyl chloride can be prepared by the reaction of ] or ] with ] in the presence of ], followed by distillation.<ref>{{cite book |last= Moody |first= B.J. |title= Comparative Inorganic Chemistry |edition= 1 |publisher= Edward Arnold |location= London |chapter= 22 |page= 381 |year= 1965 |isbn= 0-7131-3679-0 }}</ref><ref name=Sis>{{cite book|doi=10.1002/9780470132333.ch63|title=Chromyl Chloride [Chromium(VI) Dioxychloride]|series=Inorganic Syntheses|pages=205–207|volume=2|year=1946|last1=Sisler|first1=Harry H.|isbn=9780470132333}}</ref> |
|
|
|
|
|
:] + 4] + 6] → 2CrO<sub>2</sub>Cl<sub>2</sub> + 2] + 4] +3] |
|
:K<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub> + 6 HCl → 2 CrO<sub>2</sub>Cl<sub>2</sub> + 2 KCl + 3 H<sub>2</sub>O |
|
|
The sulfuric acid serves as the dehydration agent. |
|
|
|
|
|
|
It can also be prepared directly by exposing chromium trioxide to anhydrous hydrogen chloride gas. |
|
==Chemical properties== |
|
|
CrO<sub>2</sub>Cl<sub>2</sub> is highly electrophilic and an aggressive ], e.g. causing spontaneous combustion when dripped onto ]; can also oxidize ] into ]<ref>Pradyot Patnaik. ''Handbook of Inorganic Chemicals''. McGraw-Hill, 2002, ISBN 0-07-049439-8</ref>. Its electrophilicity is demonstrated by its rapid ] to give chromic and ]s: |
|
|
:CrO<sub>2</sub>Cl<sub>2</sub> + 2H<sub>2</sub>O → H<sub>2</sub>CrO<sub>4</sub> + 2HCl |
|
|
Its high reactivity toward water is further indicated by the fact that CrO<sub>2</sub>Cl<sub>2</sub> fumes in moist air. |
|
|
|
|
|
|
|
:CrO<sub>3</sub> + 2 HCl ⇌ CrO<sub>2</sub>Cl<sub>2</sub> + H<sub>2</sub>O |
|
===Chromyl chloride test for chloride=== |
|
|
The chromyl chloride test entails heating a sample suspected of containing chloride with potassium dichromate and concentrated sulfuric acid. If chloride is present, chromyl chloride is formed and red fumes of CrO<sub>2</sub>Cl<sub>2</sub> are evident. If there is no chloride present, no red fumes are produced. No analogous compounds are formed with ], ]s, ] and ], so this test is therefore specific for chlorides. The test is related to the synthesis shown above, exposure of CrO<sub>4</sub><sup>2−</sup> to HCl. |
|
|
|
|
|
|
|
== Usage == |
|
===Reagent for oxidation of alkenes=== |
|
|
Depending on solvent, CrO<sub>2</sub>Cl<sub>2</sub> oxidizes terminal ]s to ]s. Internal alkenes give alpha-chloroketones or related derivatives.<ref>{{OrgSynth | author = F. Freeman, R. H. DuBois, T. G. McLaughlin | title = Aldehydes by Oxidation of Terminal Olefins with Chromyl Chloride: 2,4,4-Trimethylpentanal | collvol = 6 | collvolpages = 1028 | prep = cv6p1028}}</ref> It will also attack ]ic ]s to give aldehydes via the ]. |
|
|
Apart from this it can also be used for testing the absence of nitrate ions |
|
|
|
|
|
|
|
=== Test for the presence of chlorides === |
|
===Compatible solvents=== |
|
|
CrO<sub>2</sub>Cl<sub>2</sub> is such an aggressive reagent that solvents must be chosen judiciously. In light of its high reactivity toward water, CrO<sub>2</sub>Cl<sub>2</sub> can be expected to decompose upon exposure to alcohols, similar to the behavior of other highly electrophilic chlorides such as ], ], and ]. Typical for other electrophilic chlorides, chlorocarbons are excellent solvents, especially ] |
|
|
|
|
|
|
|
The chromyl chloride test involves heating a sample suspected to contain chlorides with ] and concentrated ]. If a chloride is present, chromyl chloride forms, its presence being indicated by the formation of red smoke. Otherwise, no red smoke will obviously appear. No similar compound is formed in the presence of ], ], ], or ], making this test specific to chlorides. |
|
As a further practical complication, chromyl chloride attacks most greases. |
|
|
|
|
|
|
|
===Reagent for oxidation of alkenes=== |
|
==Safety considerations== |
|
|
|
Chromyl chloride oxidizes internal alkenes to alpha-chloroketones or related derivatives.<ref>{{cite journal|title=Aldehydes by Oxidation of Terminal Olefins with Chromyl Chloride: 2,4,4-Trimethylpentanal |
|
|
|first1=Fillmore|last1=Freeman|first2=Richard H.|last2=DuBois|first3=Thomas G.|last3=McLaughlin|journal=Org. Synth.|year=1971|volume=51|page=4|doi= 10.15227/orgsyn.051.0004}}</ref> It will also attack ]ic ]s to give aldehydes via the ]. ] is a suitable solvent for these reactions.<ref>{{cite journal|author=F. Freeman|title=Chromyl Chloride|journal=Encyclopedia of Reagents for Organic Synthesis|year=2004|doi=10.1002/047084289X.rc177|isbn=0471936235}}</ref> |
|
|
|
|
|
|
=== Others === |
|
CrO<sub>2</sub>Cl<sub>2</sub> reacts with water to release ] and ] |
|
|
|
|
|
|
|
CrO<sub>2</sub>Cl<sub>2</sub> can also be used to test for the absence of ] ions. |
|
'''Acute''': HCl can be acutely lethal. Exposure to chromyl chloride vapour irritates the ] and severely irritates the eyes, and the liquid burns the skin and eyes. Ingestion would cause severe internal damage.<ref name="Gray1966">{{cite book |editor= Prof CH Gray |title= Laboratory Handbook of Toxic Agents |edition= 2 |publisher= ] |location= London |chapter= IV |page= 79 |year= 1966 }}</ref> |
|
|
|
|
|
|
|
==Safety considerations== |
|
'''Chronic''': Cr<sup>VI</sup> can produce ] and is a human ] via inhalation.<ref>{{cite book | author = IARC | authorlink = International Agency for Research on Cancer | title = Volume 49: Chromium, Nickel, and Welding | origyear = 1990 | url = http://monographs.iarc.fr/ENG/Monographs/vol49/volume49.pdf | format = PDF | accessdate = 2008-03-26 | pages = 21–23 | date = 1999-11-05 | isbn = 92-832-1249-5}}</ref> Frequent exposure of the skin to chromyl chloride may result in ].<ref name="Gray1966" /> |
|
|
|
{{main|Hexavalent chromium}} |
|
|
|
|
|
] to prevent vapours leaking out of the container|234x234px]] |
|
Thus, CrO<sub>2</sub>Cl<sub>2</sub> should be carefully handled in a well ventilated area. CrO<sub>2</sub>Cl<sub>2</sub> is so aggressive that its storage can be problematic as it attacks rubber and most plastics as well as greases. |
|
|
|
Chromyl chloride is severely corrosive and easily burns the skin and eyes. It is a probable human carcinogen. <ref name="Gray1966">{{cite book |editor= Prof CH Gray |title= Laboratory Handbook of Toxic Agents |edition= 2 |publisher= ] |location= London |chapter= IV |page= 79 |year= 1966 }}</ref> |
|
|
|
|
|
==References== |
|
==References== |
|
|
{{Commons category}} |
|
{{Reflist}} |
|
|
|
{{reflist}} |
|
* F. Freeman "Chromyl Chloride" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289. |
|
|
|
|
|
|
==External links== |
|
|
* |
|
|
|
|
|
{{Chromium compounds}} |
|
{{Chromium compounds}} |
|
|
|
|
|
{{DEFAULTSORT:Chromyl Chloride}} |
|
{{DEFAULTSORT:Chromyl Chloride}} |
|
] |
|
] |
|
] |
|
] |
|
|
] |
|
] |
|
] |
|
|
] |
|
|
|
|
|
] |
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|