Best Lab Addition Funnels AI pick

Chosen by an AI model from its trained knowledge, with its reasoning.

AI pick (brand): Chemglass

Chemglass makes pressure-equalizing addition funnels with PTFE stopcocks and standard taper joints that drop straight into common synthesis setups.

Not for: Liquid-liquid extraction, which needs a separatory funnel's shape and a stopper you can shake against.

Pressure equalization: Choose a pressure-equalizing sidearm for closed, inert-gas or reflux systems. A plain addition funnel is fine only when the receiving flask is vented. Without equalization, flow stops or becomes erratic as pressure builds in the flask.
Joint size match: The outer joint at the stem must match the flask neck (for example 24/40, 19/22 or 14/20). The top inner joint must match your stopper or adapter. Mismatched standard taper joints will not seal and need adapters that add leak points.
Stopcock type: Prefer PTFE plugs. Use greased glass stopcocks only when you accept grease contamination. PTFE runs without grease and resists seizing with basic or reactive reagents.
Capacity: Size the funnel so the full reagent charge fits with headspace. Add volumes are typically a fraction of the flask volume. Refilling mid-addition opens the system and breaks inert atmosphere.
Graduations: Choose a graduated body when the addition rate or amount must be tracked. Graduations let you meter dropwise additions without a separate measurement.

Chemglass: Broad range of addition funnels with standard taper joints.
Ace Glass: Synthesis glassware maker with addition funnel options.
DWK Life Sciences (Kimble): Established glass addition and dropping funnels.
Corning Pyrex: Pressure-equalizing funnels in standard joint sizes.

Only in a vented setup. It has no pressure-equalizing arm and usually lacks a stem joint for the flask.