Lead(IV) acetate or lead tetraacetate is an metalorganic compound with chemical formula Pb(C2H3O2)4. It is a colorless solid that is soluble in nonpolar, organic solvents, indicating that it is not a salt. It is degraded by moisture and is typically stored with additional acetic acid. The compound is used in organic synthesis.[2]
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| Names | |
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| IUPAC name
Lead(IV) acetate
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| Systematic IUPAC name
Tetrakis(acetyloxy)plumbane | |
| Other names
Lead tetraacetate
Plumbic acetate | |
| Identifiers | |
3D model (JSmol)
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| ChEBI | |
| ChemSpider | |
| ECHA InfoCard | 100.008.099 |
| EC Number |
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PubChem CID
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| UNII | |
CompTox Dashboard (EPA)
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| Properties | |
| Pb(C2H3O2)4 | |
| Molar mass | 443.376 g/mol |
| Appearance | colorless or pink crystals |
| Odor | vinegar |
| Density | 2.228 g/cm3 (17 °C) |
| Melting point | 175 °C (347 °F; 448 K) |
| Boiling point | decomposes |
| soluble, reversible hydrolysis | |
| Solubility | reacts with ethanol soluble in chloroform, benzene, nitrobenzene, hot acetic acid, HCl, tetrachloroethane |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards
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Toxic |
| GHS labelling:[1] | |
  
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| Danger | |
| NFPA 704 (fire diamond) | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Structure
editIn the solid state the lead(IV) centers are coordinated by four acetate ions, which are bidentate, each coordinating via two oxygen atoms. The lead atom is 8 coordinate and the O atoms form a flattened trigonal dodecahedron.[3]
Preparation
editIt is typically prepared by treating of red lead with acetic acid and acetic anhydride (Ac2O), which absorbs water. The net reaction is shown:[4][5]
- Pb3O4 + 4 Ac2O → Pb(OAc)4 + 2 Pb(OAc)2
The remaining lead(II) acetate can be partially oxidized to the tetraacetate by Cl2, with a PbCl2 by-product:
- 2 Pb(OAc)2 + Cl2 → Pb(OAc)4 + PbCl2
Reagent in organic chemistry
editLead tetraacetate is a strong oxidizing agent,[6] a source of acetyloxy groups, and a general reagent for the preparation of organolead compounds. Some of its many uses in organic chemistry:
- Acetoxylation of benzylic, allylic,[7] and α-oxygen ether C−H bonds, for example the conversion of dioxane to 2-acetoxy-1,4-dioxane [8]
- An alternative reagent to bromine in Hofmann rearrangement[9]
- Dehydrogenation of hydrazones and hydrazines, for example that of hexafluoroacetone hydrazone to bis(trifluoromethyl)diazomethane[10][11]
- Cleavage of α-hydroxy acids[12] or 1,2-diols to their corresponding aldehydes or ketones, often replacing ozonolysis; for instance, the oxidation of di-n-butyl D-tartrate to n-butyl glyoxylate.[13]
- Reaction with alkenes to form γ-lactones
- Oxidation of alcohols carrying a δ-proton to cyclic ethers.[14]
- Oxidative cleavage of certain allyl alcohols in conjunction with ozone:[15][16]
- Transformation of 1,2-dicarboxylic acids or cyclic anhydrides to alkenes
- Conversion of acetophenones to phenyl acetic acids[17]
- Decarboxylation of carboxylic acids to alkyl halides in the Kochi reaction[18]
Safety
editLead(IV) acetate is toxic. It is a neurotoxin. It affects the gum tissue, central nervous system, kidneys, blood, and reproductive system.
References
edit- ^ "Substance Information - ECHA". echa.europa.eu.
- ^ Mihailo Lj. Mihailović; Živorad Čeković; Brian M. Mathes (2005). "Lead(IV) Acetate". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rl006.pub2. ISBN 978-0-471-93623-7.
- ^ Schürmann, M.; Huber, F. (1994). "A redetermination of lead(IV) acetate". Acta Crystallographica Section C. 50 (11): 1710–1713. doi:10.1107/S0108270194006438. ISSN 0108-2701.
- ^ J. C. Bailar, Jr. (1939). "Lead Tetracetate". Inorganic Syntheses. Inorganic Syntheses. Vol. 1. pp. 47–49. doi:10.1002/9780470132326.ch17. ISBN 978-0-470-13232-6.
- ^ M. Baudler (1963). "Lead(IV) Acetate". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 2. NY,NY: Academic Press. p. 767.
- ^ J. Zýka (1966). "Analytical study of the basic properties of lead tetraacetate as oxidizing agent" (PDF). Pure and Applied Chemistry. 13 (4): 569–581. doi:10.1351/pac196613040569. S2CID 96821219. Retrieved 19 December 2013.
- ^ "(1R,5R)-(+)-Verbenone of High Optical Purity". Organic Syntheses. 72: 57. 1995. doi:10.15227/orgsyn.072.0057.
- ^ Organic Syntheses, Vol. 82, p.99 (2005) Article.
- ^ Baumgarten, Henry; Smith, Howard; Staklis, Andris (1975). "Reactions of amines. XVIII. Oxidative rearrangement of amides with lead tetraacetate". The Journal of Organic Chemistry. 40 (24): 3554–3561. doi:10.1021/jo00912a019.
- ^ Middleton, W. J.; Gale, D. M. (1970). "Bis(Trifluoromethyl)Diazomethane". Organic Syntheses. 50: 6. doi:10.15227/orgsyn.050.0006.
- ^ Robert K. Muller, Renato Joos, Dorothee Felix, Jakob Schreiber, Claude Wintner, and A. Eschenmoser (1976). "Preparation of N-Aminoaziridines: trans-1-Amino-2,3-diphenylaziridine, 1-Amino-2-phenylaziridine, and 1-Amino-2-phenylaziridinium Acetate". Organic Syntheses. 55: 114. doi:10.15227/orgsyn.055.0114.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Ōeda, Haruomi (1934). "Oxidation of some α-hydroxy-acids with lead tetraacetate". Bulletin of the Chemical Society of Japan. 9 (1): 8–14. doi:10.1246/bcsj.9.8.
- ^ Organic Syntheses, Coll. Vol. 4, p.124 (1963); Vol. 35, p.18 (1955) Article.
- ^ M B Smith, J March. March's Advanced Organic Chemistry (Wiley, 2001) (ISBN 0-471-58589-0)
- ^ Álvarez Manzaneda, E. J.; Chahboun, R.; Cano, M. J.; Cabrera Torres, E.; Álvarez, E.; Álvarez Manzaneda, R.; Haidour, A.; Ramos López, J. M. (2006). "O3/Pb(OAc)4: a new and efficient system for the oxidative cleavage of allyl alcohols". Tetrahedron Letters. 47 (37): 6619–6622. doi:10.1016/j.tetlet.2006.07.020.
- ^ Conversion of 1-allylcyclohexanol to cyclohexanone, in the proposed reaction mechanism the allyl group is first converted to a trioxalane according to conventional ozonolysis which then interacts with the alkoxy lead group.
- ^ Myrboh, B.; Ila, H.; Junjappa, H. (1981). "One-Step Synthesis of Methyl Arylacetates from Acetophenones Using Lead(IV) Acetate". Synthesis. 2 (2): 126–127. doi:10.1055/s-1981-29358.
- ^ Jay K. Kochi (1965). "A New Method for Halodecarboxylation of Acids Using Lead(IV) Acetate". J. Am. Chem. Soc. 87 (11): 2500–02. doi:10.1021/ja01089a041.