PARALDEHYDE

PARALDEHYDE



Brand Names : Paracetaldehyde; Paraldehydum; The trimer of acetaldehyde.



Paraldehyde is a polymer of acetaldehyde prepared by the polymerization of acetaldehyde catalyzed by HCl and H2SO4, at medium to high temperature. When a drop of concentrated H2SO4, is added to acetaldehyde, a vigorous reaction takes place.


 The polymerization to paraldehyde is controllable if concentrated HCl is used in place of HSO, At the end of the reaction, the product is shaken with a dilute solution of sodium bicarbonate, separated, dried over fused potassium carbonate and fractionally distilled.

Paraldehyde is a colourless liquid, b.p. 123-126°, with characteristic aromatic odour and warm, but disagreeable acrid taste; neutral to litmus. 


It is soluble in 8 parts of water at 25°, in 17 parts boiling water; miscible with alcohol, chloroform, ether and volatile oils. It is solidified at 12° to form a crystalline mass which should be liquefied before use. It has solvent action upon rubber, polystyrene and styrene acrylonitrile copolymer, therefore, paraldehyde should not be taken in plastic syringes made with these materials. It gives acetaldehyde on heating with dilute HCl or on warming with concentrated HSO. 

It may be oxidized to form acetic acid on storage. Since oxidation occurs more rapidly in opened, partially filled containers, the drug should not be dispensed from container that has been opened for more than 24 hours.

Uses: Paraldehyde is a hypnotic and sedative with anticonvulsant effects.

Side Effect
As paraldehyde decomposes on storage, deaths from corrosive poisoning have followed the use of such material. It has an unpleasant taste and imparts a smell to the breath; it may cause skin rashes.


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