Stopper protection, tin foil for rubber

Stirrer, mercury seal, 7, 80 Stoppers, asbestos and water glass 5, 9 Stopper protection, tin foil for rubber, 4, 68... 

A 2-1. round-bottom flask is clamped to a ring-stand and equipped with a rubber stopper protected with tin foil and carrying a glass stirrer with mercury seal and a reflux condenser. (Cf. Org. Syn. i, 4, Fig. 1, a.) As an outlet for the hydrogen chloride, the top of the condenser is provided with a bent tube which almost touches the surface of the water in a half-filled i-l. flask. 

Cork stoppers, or screw caps of plastic or metal, are used for glass bottles screw caps with inserted seals only are used for cans to provide a vapor-tight closure seal. C rks must be of good quality, clean, and fiee from holes and loose bits of cork. Never use rubber stoppers. Contact of the sample with the cork can be prevent by wrapping tin or aluminum foil around the cork before forcing it into the bottle. Screw caps must be protected by a cork disk faced with tin or aluminum foil, an inverted cone polyseal or other material that will not affect petroleum or petroleum products. The fluorinated bottles are supplied with polypropylene screw caps. 

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