Question

In the Polymers Lab .... If the same amounts of sebacoyl chloride, 1,6-hexanediamine and sodium hyrdroxide were combined as above, but a solvent was used to afford a homogenous reaction mixture, would the yield of polymer increase, decrease, or remain the same? Explain?

Answer 1

Ans. Sebacoyl chloride immediately reacts with water to from HCl. It reduces the reactivity of sebacoyl chloride towards 1,6-adiamniohexane, thus also reduces formation of product nylon or reduces the yield.

So, the reaction mixture is set up in three different layers in the beaker (reaction vessel)-

Bottom layer (layer 1). Sebacoyl chloride

Middle layer (layer 2) : 1,6-adiamniohexane

Uppermost layer (layer 3): aqueous solution of NaOH. Water with density lower than 1,6-adiamniohexane floats on the middle layer.

This set up maximizes reaction of sebacoyl chloride with 1,6-adiamniohexane forming nylon simultaneously with separating sebacoyl chloride from the aqueous phase.

Carrying the reaction in a solvent that better homogenizes the three layers will reduce the yields because sebacoult chloride reacts with water and no longer be useful to react with 1,6-adiamniohexane .