Chromyl Chloride Research Articles

Visible-laser photodeposition of chromium oxide films and single crystals

Visible-laser deposition reactions of the chromyl chloride vapor, CrO2Cl2, have been developed for direct writing of chromium oxides. Deposition at low laser power is by photolysis of adsorbed CrO2Cl2 molecules. Higher powers initiate deposition photochemically and continue it with a combined photolytic/pyrolytic reaction, simultaneously inducing a solid phase conversion of the deposited film. Mixed Cr2O3/CrO2 thin films of 1 nm to several micrometer thickness, as well as 1-mm-long single crystals of Cr2O3, were grown, the latter at rates up to 3 μm/s. The thin films are strongly ferromagnetic. Mass spectrometer and optical transmission measurements show that surface kinetics dominate the nucleation and growth rates.

Multiphoton ionization and photochemistry of chromyl chloride in supersonic cluster beams

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMultiphoton ionization and photochemistry of chromyl chloride in supersonic cluster beamsRobert G. Wheeler and Michael A. DuncanCite this: J. Phys. Chem. 1986, 90, 8, 1610–1614Publication Date (Print):April 1, 1986Publication History Published online1 May 2002Published inissue 1 April 1986https://doi.org/10.1021/j100399a031RIGHTS & PERMISSIONSArticle Views49Altmetric-Citations5LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (679 KB) Get e-Alerts

Determination of organic sulphides by enthalpimetry using chromyl chloride

Thermometric titration with chromyl chloride and direct injection enthalpimetry with the same reagent have been used for the determination of sulphides in hydrocarbon solvents; the second procedure was found to be superior. Chromyl chloride and sulphides react in a 1 : 1 ratio, producing a brown precipitate, the heat of reaction being 250 kJ mol–1. The limit of determination is 3 p.p.m. and the relative standard deviation 3.3% at 60 p.p.m. of sulphide-sulphur. The method can be applied in the presence of unsaturated compounds and polycyclic aromatic hydrocarbons. Polycyclic aromatic hydrocarbons also react with chromyl chloride, but the reaction with sulphides is dominant. The method has been suggested for the determination of sulphide-sulphur in petroleum products.

Oxidation of aromatic amines with chromyl chloride-I : Oxidation of aromatic primary amines

The oxidation of aromatic primary amines with chromyl chloride in carbon tetrachloride or chloroform, results in the formation of intermediate solid adducts (Etard adducts) which, on hydrolysis, give azobenzenes( 1), 1,4-benzoquinones( 2),anilino-1,4-benzoquinones( 3), 1,4-benzoquinone anils( 4)and anilino-1,4-benzoquinone anils ( 5) in yields which depend on the position, nature and degree of substitution of the ring.

Oxidation of aromatic amines with chromyl chloride-II : Studies on the intermediate solid adducts

Oxidation of aromatic primary amines with chromyl chloride results in the formation of intermediate solid Etard adducts (C. Nallaiah and J.A. Strickson, Tetrahedron 42,4083 ( 1986)). Elemental analysis of the adducts indicates that the anilines, which give 1,4-benzoquinone anils in good yields, form adducts close to a 1:1 stoichiometry with the oxidant while those forming 1,4-benzoquinones in substantial yields form 1:2 adducts. Magnetic measurements on the adducts reveal that chromium atoms are mainly present m the oxidation state chromium(IV). IR studies indicate that the adducts comprise of 1,4-benzoquinone imines and di-imines as ligands and that giant molecules are formed by chloro and hydroxy bridges.

Report on the extremely low threshold for the CO2 laser induced multiple photon absorption and dissociation processes in chromyl chloride

Abstract We have studied the behaivior of the CrO 2 Cl 2 molecule upon irradiation with an unfocused, low power (0.45 J/cm 2 pulsed CO 2 laser using a visible dye laser as a probe of the population changes in the vibrationless ground electronic state and various low-lying vibrational levels. Wavelength and time-resolved measurements indicate that the vibrationless ground state is depleted as a result of the CO 2 laser pumping and that the recovery of the ambient population does not take palce even after 5.0 milliseconds. Mass spectroscopic analysis of the CO 2 laser irradiated samples suggests an extremely low thereshold for dissociation in the case of CrO 2 Cl 2 .

Physicochemical studies on solid products of reactions of chromyl chloride and chromyl acetate with alkylaromatics. Part I. Infrared spectra and magnetic measurements

Reaction of chromyl chloride, CrO2Cl2, with various alkylaromatics leads to solid products of composition 2CrO2Cl2 · HR (where HR is an alkylaromatic); however, they are not the simple adducts as the oxidation state of chromium appears to be reduced from VI to IV. The products of chromyl acetate reactions with the same hydrocarbons are monochromo(IV)- and dichromo(IV)-hydroxyacetates depending on the method of preparation. Infrared spectra and magnetic measurements were interpreted as showing that none of these compounds are the adducts of chromyl chloride or chromyl acetate but that all contain chromium(IV).

Reactions of Chromyl Chloride with Carboxylic Acids and Carboxylic Acid Anhydrides

Abstract Chromyl Chloride reacts with carboxylic acids [RCOOH where R = C2H5, n-C3H7, CH2CI, CHCl2 and CCI3] to give reduced chromium(III) carboxylates, [Cr3 O(OOCR)6 (H2O)3 ]Cl. Magnetic susceptibility, UV-visible and IR measurements are all consistent with their trinuclear basic structures. Reactions of chromyl chloride with carboxylic acid anhydrides [(RCO)2O where R = CH3 , C2H5 and n-C3H7 ] give dinuclear oxo-bridged complexes of the type, [Cr2O(OOOCR)3 ]Cl. These compounds behave as non-electrolytes in polar organic solvents. IR spectra suggest the presence of bridging carboxylato groups containing Cr-O -Cr chains. Their low magnetic moment values suggest polymeric structures exhibiting antiferromagnetic coupling between Cr atoms.

Indirect determination of chloride as chromyl chloride by atomic-absorption spectrophotometry

A method for the determination of chloride in aqueous solution by atomic-absorption Spectrophotometry is described. The chloride is converted into chromyl chloride, which is extracted into carbon tetrachloride and subsequently back-extracted and determined in a solution buffered with NH4H2PO4/(NH4)2HPO4. Calibration plots of the atomic absorption of the aqueous back-extracted phase at the chromium 425.4 nm resonance line are linear in the range 5–270μg of chloride. The calibration graph can be obtained directly with aqueous solutions of Cr(VI). The proposed method can be applied directly to mineral and medicinal water samples.

X-Ray crystallographic evidence for intermolecular hydrogen bonding, including a bifurcated hydrogen bond, between nitro and hydroxy groups in two 3-chloro-6-nitrobicyclo[2.2.1]heptan-2-ols

The structures of 3-exo-chloro-6-exo-nitrobicyclo [2.2.1]heptan-2-exo-ol (7) and 3-exo-chloro-6-exo-nitrobicyclo[2.2.1]heptan-2-endo-ol (8), prepared in moderate yields by oxidation of 5-endo-nitrobicyclo[2.2.1]hept-2-ene (3) with chromyl chloride followed by reduction of the crude chloroketone mixture with sodium borohydride, were determined by X-ray crystallography. In compound (7), linear hydrogen bonds occur intermolecularly between the hydroxy and nitro groups, while in compound (8), the intermolecular hydrogen bonds between these groups are unsymmetrically bifurcated.

Thermal investigations of some chromium(IV) complexes

The thermal decompositions of 15 solid products of reactions of chromyl chloride and chromyl acetate with alkylaromatics were studied by means of a derivatograph in argon and air atmospheres. In the case of the chromyl chloride complexes, 2CrIVO2Cl2 · HR (HR= =hydrocarbon molecule), the formation of Cr2O3Cl2 was observed as a labile intermediate in the inert atmosphere, while in air the abrupt decomposition of the complexes leads to Cr2O3 as a residue. The decompositions of monochromium(IV) hydroxoacetate and dichromium(IV) hydroxoacetate proceed through the intermediate Cr2O3(CO3) both in argon and in air atmospheres. Characteristic temperatures are discussed and the activation energiesE a of the particular steps of thermal decompositions were calculated in all cases.

Chromium Contents of Standard Rock Samples: A Detailed Investigation by Radiochemical Neutron Activation Analysis

The reported values for the chromium contents of standard acidic rocks show a large spread, making it difficult to assign firm recommended values. A radiochemical neutron activation analysis procedure was developed and its reliability examined critically. The method involves separation of chromium as chromyl chloride by distillation followed by precipitation as barium chromate. The chromium content of a number of international standard rocks has been determined and results obtained are critically reviewed in relation to the available data.

On the Interaction of CrO2Cl2 Vapor with the Surface of γ-Al2O3 and the Formation of a Chromium Oxide Covering

Abstract Samples of γ-Al2O3 containing different amounts of residual hydroxyl groups were obtained by thermal treatment. The possibility of interaction of the surface hydroxyl groups of γ-Al2O3 with chromyl chloride vapor was studied by IR spectroscopy. The hydrogen chloride evolved as a result of the reaction interacts with both strained Al–O–Al bridges and the surface OH groups. Different types of OH groups show different reactivities with respect to the interaction with CrO2Cl2. Bands at 3780 and 3700 cm−1 are due to OH groups which have a much higher reactivity than the OH groups responsible for bands at 3744 and 3733 cm−1. Not all of the OH groups participate in the surface reaction. Decrease in their surface density results in increase in the reactivity. Modification of the γ-Al2O3 surface is achieved by reaction cycles consisting of treatment with CrO2Cl2 vapor and hydrolysis of the compounds obtained by water vapor. As a result, an increase in the chromium oxide amount on the surface of γ-Al2O3 is observed. This is ascribed to the “secondary” OH groups formed after the hydrolysis.

The state of Cr(VI) on the Phillips polymerization catalyst: II. The reaction between silica and CrO 2Cl 2

The reaction between chromyl chloride vapor and the hydroxyl population on calcined silica was examined at 200 °C in a flow system. When the silica had been calcined at high temperatures (≥800 °C) the CrO 2Cl 2 attached by losing one chloride per Cr. This indicates the formation of a surface-SiOCrO 2Cl species which, upon contact with ethylene, failed to develop any polymerization activity. However, when the silica had been calcined at low temperatures (≤400 °C), most of the CrO 2Cl 2 attached by losing two chlorides per Cr, indicating the formation of a surface chromate species by reaction with hydroxyl pairs. On contact with ethylene this species developed polymerization activity very much like the conventional CrO 3/silica catalysts, suggesting that here too the active species could begin as a surface chromate.

The use of van der Waals molecules to detect a mode selective nonradiative process in chromyl chloride

A free jet expansion was used to form van der Waals complexes of helium and chromyl chloride of the type CrO2Cl2–He(x), x = 1,2,... The vibronic bands of both the complex and the corresponding parent molecule have been excited using a tunable cw dye laser, and the fluorescence excitation spectra were recorded. The lifetimes of the complexes were measured and were found to be in the range 11–121 ps. The complexes undergo vibrational predissociation after excitation. For the van der Waals molecules we have evidence of competition between the vibrational predissociation and a nonradiative process in the CrO2Cl2 portion of the complex. The fluorescence intensity of a vibronic band of the complex relative to the corresponding band of the uncomplexed parent molecule shows that there is a mode selective nonradiative process in the 1B1 excited state of CrO2Cl2. The cross section for this nonradiative process increases with increasing excitation of the ν4 mode, the CrCl2 bend. A kinetic scheme is presented to interpret these observations, and the utility of this effect to measure vibrational predissociation rates in polyatomic molecule–rare gas van der Waals complexes is discussed.

Molecular structure and quadratic force field of chromyl chloride, CrO2Cl2

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMolecular structure and quadratic force field of chromyl chloride, CrO2Cl2C. J. Marsden, Lise Hedberg, and Kenneth HedbergCite this: Inorg. Chem. 1982, 21, 3, 1115–1118Publication Date (Print):March 1, 1982Publication History Published online1 May 2002Published inissue 1 March 1982https://doi.org/10.1021/ic00133a047RIGHTS & PERMISSIONSArticle Views83Altmetric-Citations40LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (441 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

The reaction of chromyl chloride and O-silylated enolates: a novel regiospecific route to α-hydroxy ketones.

Chromyl chloride reacts regiospecifically with O-silylated enolates to form α-hydroxy ketones.

‘Chromyl carbonyl’. Synthesis of [CrO2(CO)2] in low-temperature matrices

Photolysis of [Cr(CO)6] in O2-doped Ar matrices at low temperatures produces, inter alia, a species which contains both CO and O2. Experiments with 13CO-enriched [Cr(CO)6] and with matrices doped with 16O2, 16O18O, and 18O2 show that this species contains two CO groups and two oxygen atoms double-bonded to the metal. This structure is thus ‘chromyl carbonyl’ and further evidence for this comes from the photochemical generation of the species from chromyl chloride in solid CO. The generation of CO and CO2 during the carbonyl photolysis suggests a possible mechanism involving oxidation of CO to CO2 on the metal centre.

Mutagenicity and toxicity of chromyl chloride

Mutagenicity and toxicity of chromyl chloride

The origin of the infrared multiphoton induced luminescence of chromyl chloride

We have studied systematically the luminescence induced when CrO2Cl2 is infrared multiphoton excited by a moderate fluence (0–15 J/cm2) CO2 laser. This includes the dependence of the full luminescence spectrum on CO2 laser fluence, and for various spectral regions of the luminescence their dependence on CO2 laser wavelength and fluence, their intramolecular decay rates, and using a time-of-flight technique the translational temperatures associated with their sources. These measurements show that two species contribute to the luminescence. In addition, a chemical identification of these species is made by preceding the IR laser pulse with a UV laser pulse to photochemically prepare the CrO2Cl fragment, and isolate its contribution to the luminescence. Strong evidence is obtained in support of both CrO2Cl fragment and CrO2Cl2 parent contributions to the luminescence. The relative contributions of the two to the luminescence and an absolute yield for the IR multiphoton induced dissociation of CrO2Cl2 into CrO2Cl as functions of CO2 laser fluence are estimated.