546-67-8 Usage
Chemical Description
Lead tetraacetate is a chemical reagent used in organic chemistry to oxidize alcohols to aldehydes or ketones.
Uses
Used in Organic Synthesis:
Lead tetraacetate is used as a highly selective oxidizing agent in organic synthesis for various applications. It is particularly useful in the oxidation of glycols into aldehydes, the preparation of cyclohexyl acetate, the production of oxalic acid, and in the structural analysis of sugars.
Used in the Structural Determination of Sugars and Polyols:
Lead tetraacetate is used as a reagent in the structural determination of sugars and other polyols. The rate of oxidation of cis glycols is more rapid than that of trans isomers, a property widely used to differentiate between these isomers.
Used in the Preparation of 1,4-Dioxene:
Lead tetraacetate is used as a reagent in the preparation of 1,4-dioxene from dioxane, involving 2-acetoxy-1,4-dioxane as an intermediate.
Used in the Preparation of Bis(trifluoromethyl)diazomethane:
Lead tetraacetate is used in the preparation of bis(trifluoromethyl)diazomethane from hexafluoroacetone hydrazone.
Used in the Synthesis of Gamma-Lactones, Cyclic Ethers, and N-Butyl Glyoxylate:
Lead tetraacetate reacts with alkenes, alcohols having a delta-proton, and di-n-butyl d-tartrate to produce gamma-lactones, cyclic ethers, and n-butyl glyoxylate, respectively.
Used in the Kochi Reaction:
Lead tetraacetate is used in the Kochi reaction for the decarboxylation of carboxylic acids to alkyl halides, serving as an alternative reagent to bromine in this process.
Used in the Hofmann Rearrangement:
Lead tetraacetate is used as an alternative reagent to bromine in the Hofmann rearrangement, a chemical reaction that involves the conversion of an amide into a primary amine.
Preparation
Lead tetraacetate is prepared by dissolving lead tetroxide in warm glacial acetic acid followed by cooling. On cooling, the tetraacetate crystallizes out while lead acetate remains in the solution:
Pb3O4 + 8CH3COOH→Pb(CH3COO)4 + 2Pb(CH3COO)2 + 4H2O
Yield is improved by adding chlorine gas to the mixture. Alternatively, the compound may be prepared by adding a mixture of glacial acetic acid and acetic anhydride to lead tetroxide and heating the solution gently. Acetic anhydride converts the water formed in the reaction into acetic acid, thus preventing hydrolysis of the product lead tetraacetate.
Preparation
Lead tetraacetate can be prepared by reaction of red lead with acetic acid The other main lead acetate is lead (II) acetate.
Reactions
Lead tetraacetate, on treatment with water, hydrolyzes to lead dioxide and acetic acid:
Pb(CH3COO)4 + 2H2O → PbO2 + 4CH3COOH
Lead tetraacetate is a selective oxidizing agent causing oxidative cleavage of polyhydroxy compounds. It cleaves compounds that have hydroxyl groups on adjacent carbon atoms, breaking the carbon-carbon bonds to form carbonyl compounds, such as aldehydes, ketones or acids. The reaction is carried out in organic solvents. A typical example is as follows:
OH—CH2—CH2—OH + Pb(CH3COO)4 → 2CH2O + Pb(CH3COO)2 + 2CH3COOH
Air & Water Reactions
Unstable in air. Reacts with water to form brown lead dioxide and acetic acid [Merck 11th ed. 1989].
Reactivity Profile
Organometallics are strongly reactive with many other groups. Incompatible with acids and bases. Organometallics are good reducing agents and therefore incompatible with oxidizing agents. Often reactive with water to generate toxic or flammable gases. Generally highly toxic. Often react on contact with tissues to give toxic products.
Health Hazard
Early symptoms of lead intoxication by ingestion are most commonly gastrointestinal disorders, colic, constipation, etc.; weakness, which may go on to paralysis chiefly of the extensor muscles of the wrists and less often of the ankles, is noticeable in the most serious cases. Ingestion of a large amount causes local irritation of the alimentary tract; pain, leg cramps, muscle weakness, paresthesias, depression, coma, and death may follow in 1 or 2 days. Contact causes severe irritation of eyes and can burn skin.
Fire Hazard
Behavior in Fire: Can increase the intensity of a fire when in contact with combustible material. Cool containers with plenty of water.
Safety
Lead (IV) acetate may be fatal if ingested, inhaled, or absorbed through skin. It causes irritation to skin, eyes, and respiratory tract. It is a neurotoxin. It affects the gum tissue, central nervous system, kidneys, blood, and reproductive system.
Check Digit Verification of cas no
The CAS Registry Mumber 546-67-8 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 5,4 and 6 respectively; the second part has 2 digits, 6 and 7 respectively.
Calculate Digit Verification of CAS Registry Number 546-67:
(5*5)+(4*4)+(3*6)+(2*6)+(1*7)=78
78 % 10 = 8
So 546-67-8 is a valid CAS Registry Number.
InChI:InChI=1/4C2H4O2.Pb/c4*1-2(3)4;/h4*1H3,(H,3,4);/q;;;;+2/p-4
546-67-8Relevant articles and documents
Metal hydrates and salts of carboxylic acids
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, (2008/06/13)
A metal salt of a carboxylic acid is formed by contacting a carboxylic acid with an activated metal. The activated metal is formed by combining a first metal with a second metal which has an affinity for hydrogen in the presence of a proton source. Typically, an activated aluminum is formed from a highly pure aluminum rod combined with an alloy of indium and gallium in the presence of hydrochloric acid. The addition of excess water in the presence of the carboxylic acid and activated metals forms a polymeric metal salt from a water soluble carboxylic acid.
