Eisco - Separating Funnel, 250ml, Pressure Equalizing, Pear Shaped - 19/26 Plastic Stopper, PTFE Key Stopcock, Borosilicate Glass

This 250mL pressure equalizing separating funnel is made from borosilicate 3.3 glass in a pear shape, with a PTFE key stopcock, a 19/26 socket, and an interchangeable polypropylene stopper. A side arm runs from the funnel body past the stopcock into the vessel below, sharing headspace pressure between the two. Without that connection, adding liquid into a sealed system creates a partial vacuum above the reaction that stalls the flow and can pull the funnel dry. With it, addition proceeds at a set rate into apparatus under reflux, under nitrogen, or otherwise closed to atmosphere. The funnel is built for controlled reagent addition and distillation rather than extraction alone. The PTFE key stopcock runs without grease, gives leak-proof flow control down to dropwise addition, and resists chemical attack during prolonged contact with aggressive organics and strong acids. The funnel is autoclavable at 121°C, and the polypropylene stopper seals securely and resists chemical exposure. Borosilicate 3.3 glass provides thermal shock resistance and chemical durability.