PARALDEHYDE

PRODUCT IDENTIFICATION

TOXICITY

RAW MATERIALS

CLASSIFICATION

GENERAL DESCRIPTION

Paraldehyde (also called paracetaldehyde) , colourless highly flammable, disagreeable taste and pungent odored liquid, is a cyclic trimer of acetaldehyde contains a six-membered ring of alternating carbon and oxygen atoms with a hydrogen atom and a methyl group attached to each carbon atom. ( tetramer is metaldehyde, which has a similar structure to the trimer but with an eight-membered ring.). It boils at 124 C and melts at a temperature of 12.5 C. It is used as a used as a solvent for fats, oils, waxes, rubber and resins, as a substitute for acetaldehyde and as an intermediate for organic chemicals, dyestuffs, accelerators for vulcanizations, rubber oxidants, etc. It is a sedative-hypnotic drug  But side-effects are expected like digestive upsets and, in large doses, prolonged unconsciousness. Paraldehyde is available on prescription only; paraldehyde should be used with caution in people with disease of the airways or lungs. Paraldehyde is commercially prepared the polymerization of acetaldehyde with a small amount of sulfuric acid; then neutralization with calcium carbonate and purifying by fractional distillation are followed.

PHYSICAL AND CHEMICAL PROPERTIES

REFRACTIVE INDEX

27.5 C

It is easily depolymerized to acetaldehyde

APPLICATIONS

It is used as a used as a solvent for fats, oils, waxes, rubber and resins, as a substitute for acetaldehyde and as an intermediate for organic chemicals, dyestuffs, accelerators for vulcanizations, rubber oxidants, etc. It is a sedative-hypnotic drug

APPEARANCE

ASSAY (G.C)

99.5% min

ACETIC ACID

0.3% max

WATER

0.1% max

Aldehydes are organic compounds containing -CHO radical, in which a carbon atom forms a solid bond with an oxygen atom and is also bonded to a hydrogen atom and another group denoted by R, which can be a second hydrogen atom, an alkyl group, or an aryl group. The most important and the simplest examples are methanal (formaldehyde), HCOH, and ethanal (acetaldehyde), CH₃CHO.( In systematic chemical nomenclature, aldehyde names end with the suffix -al). Formaldehyde is used to make synthetic resins by reaction with phenols, urea, and melamine, as a chemical intermediate, as an embalming fluid, and as a disinfectant. Acetaldehyde is used chiefly to manufacture acetic acid. They are unpleasant-smelling liquids widely used in the chemical industry, whereas aromatic aldehydes frequently have pleasant smells and are used widely as flavourings and perfumes. An example is  benzaldehyde (benzenecarbaldehyde, C₆H₅CHO), a derivative of benzene with an aldehyde group attached to the ring. It is a colourless oil smelling of almonds offer applications to both in perfumes and flavourings. Aldehydes are formed by oxidation of primary alcohols; further oxidation yields carboxylic acids. Aldehydes have certain characteristic addition and condensation reactions. Aldehydes can be reduced to primary alcohols (ketones to secondary alcohols). Aldehydes form cyanohydrins with hydrogen cyanide, acetals with alcohol, yellow-orange solid derivatives with DNP ( 2,4-dinitrophenylhydrazones) and undergo condensation reactions to yield oximes (compounds containing the group C:NOH), hydrazones (organic compounds containing the group =C:NNH₂), and semicarbazones (organic compounds containing the unsaturated group =C:N.NH.CO.NH₂). Aldehydes readily polymerize.