Question

Explain why the preparation of nylon-6,10 occurs under milder conditions when decanedioyl dicholride is used instead of decanedioic acid

Answer 1

Polymers are large molecules made up by joining together many small molecules. The small molecules that go into making a polymer are called monomers. Polymers are formed by condensation reaction where two (or more) molecules join together to form one larger molecule and a small molecule typically water or HCl being produced as a side product.

In the preparation of Nylon-6,10 the monomers which condense are 1,6-hexanediamine ( hexamethylene diamine) and sebacoyl chloride ( decadioyl chloride ). Both amine ends of the 1,6-diaminohexane react with both acid chloride ends of the sebacoyl chloride to form new amide linkages. The polymer which forms is made up of alternating 1,6-diaminohexane and sebacoyl groups. This is called an alternating copolymer. This particular Nylon is made of units of 6 carbons between two nitrogen atoms, an amide linkage, an another unit of 10 carbons. This repeats many many times; therefore this is Nylon-6,10.    

The reaction can also be carried out using diacid (decadioic acid) instead of diacid chloride. However, the advantage of using diacidchloride is that acid chloride being much more reactive than acids, the same reaction can be carried out at much milder condition.