Precipitation is also useful to isolate the products of a reaction during workup. Ideally, the product of the reaction is insoluble in the reaction solvent. Thus, it precipitates as it is formed, preferably forming pure crystals. An example of this would be the synthesis of porphyrins in refluxing propionic acid.
Freebase(0.00 / 0 votes)Rate this definition: Cellophane. Cellophane is a thin, transparent sheet made of regenerated cellulose. Its low permeability to air, oils, greases, bacteria and water makes it useful for food packaging.
Cellophane is a plastic, foil-like material, like the Saran Wrap you would use to cover foods. It is made of Celluose fibers from wood, cotton, or hemp, which is dissolved in alkali and carbon disulfide, and then soaked in sulfuric acid and sodium sulfate.