Question

When setting up the reflux condenser, does it matter if the water flows into the bottom or the top of the condenser? If so, does it have to flow into the bottom or the top, and why? If not, why does it not matter?

Reaction 2: Reduction NO2 NH4HCO2 NH2 + NO2 Pd/C NO2 NH2 NH2 m-methylaniline p-methylaniline 0-methylaniline ortho meta para Procedure for Reaction 2: 1) The mixture of ortho, meta, and para isomers obtained from reaction 1 (2.4 g, 17.5 mmoles) was added to a 50 mL round bottom flask. 2) Ethyl acetate (12mL) was added followed by 3.6 g (57.1 mmoles) of NH4HCO2 and 100 mg of 10% Pd/C. 3) The mixture was stirred for 15 min at room temperature. 4) A reflux condenser was attached, and the mixture was refluxed with stirring for 1 h. 5) After verifying completion of reaction by TLC, the reaction mixture was dried over anhydrous sodium sulfate and the solids were filtered through a pad of filter-aid and rinsed with ethyl acetate (2 x 5 ml). 6) The solution of the three isomers of methylaniline in ethyl acetate was used directly in reaction 3.

Answer 1

Generally reflux condenser is used for prevention of escaping of organic species having low melting point but reaction is proceeding at higher temperatures.

It will matter that water flows in to top or bottom.

When cold water flows from bottom to top than condenser will able to prevent escaping of organic compounds, because when cold water flows from bottom to top than cold water absorb much temperature from vapour of organic compounds and condense it and prevent escaping.

But when flows from top to bottom than it will least able to prevent escaping of organic compounds.and again hot water vaporise the organic compounds at bottom.

A fig for good set up of condenser-

water out water in