Experiment 25:

ORGANIC POLYMERS: THE SYNTHESIS OF NYLON

Objectives:

To synthesize Nylon 6,10 from hexamethylene diamine and sebacoyl chloride.

To determine the length of the Nylon formed using a simple mathematical calculation.

SYNTHESIS OF AN AMIDE

Carboxylic Acid

Reacting a carboxylic acid with an amine yields an amide. Water is a by-product, and this reaction is slow without a catalyst.

R N

H

H

+ C

O

HO

R catalystR N

H

C

O

R + H2O

amine amide

SYNTHESIS OF AN AMIDE

amine Acid chloride

amide

R N

H

H

+ C

O

Cl

R R N

H

C

O

R + HCl

By using a carboxylic acid chloride, a more reactive carboxylic acid derivative, the rate of reaction can be increased. In this reaction, HCl is the by-product.

MECHANISM

RC

Cl

O

+

R'N

H

H

RC

Cl

O

NR' H

H

+ OHR

CCl

O

NR' H

RC

N

O

H

R'

SYNTHESIS OF NYLON 6,10

In order to make a polyamide, such as Nylon 6,10, the amine molecule must have a –NH2 group at each end, and the acid chloride must have a –COCl group at each end.

The diamine and the diacid chloride bond together, end-on-end, to form very long chains.

Nylon 6,10 is made from hexamethylene diamine (the diamine) and sebacoyl chloride (the diacid chloride).

Hexamethylene diamine

Sebacoyl

chloride

N

H

H

CH2CH2CH2CH2CH2CH2 N

H

H

C

O

Cl

CH2CH2CH2CH2CH2CH2CH2CH2 C

O

Cl

SYNTHESIS OF NYLON 6,10

N

H

H

CH2CH2CH2CH2CH2CH2 N

H

H

C

O

Cl

CH2CH2CH2CH2CH2CH2CH2CH2 C

O

Cl

HN CH2CH2CH2CH2CH2CH2

HN C

O

CH2CH2CH2CH2CH2CH2CH2CH2 C

O

HN CH2CH2CH2CH2CH2CH2

HN HCl

HN (CH2)6

HN C

O

(CH2)8 C

O

+

+

Nylon 6,10 =n n

Hexamethylene diamine

Sebacoyl

chloride

CLASSIFICATIONS OF SYNTHETIC POLYMERS

Synthetic polymers are classified by their method of synthesis.

Chain-growth Step-growth

polystyrene Polyamides (nylon)

Synthetic Method

NATURAL ORGANIC POLYMERS

Proteins

hair, skin, tissue

Polysaccharides

cellulose, starch

Polynucleotides

DNA, RNA

SYNTHETIC ORGANIC POLYMERS

Nylons Polyesters Acrylics Polyvinyls

Plastic sheeting and plumbing materials

Polystyrenes Insulating materials

EXPERIMENTAL PROCEDURE

(Synthesis)

Pour diamine solution and diacid chloride in separate beakers.

Using forceps, grasp the film that forms at the interface of the two liquids.

Pull up slowly and wrap end of nylon string around a test tube.

Rotate the tube and count the number of revolutions made before no more nylon can be produced.

EXPERIMENTAL PROCEDURE

(Analysis)

Calculate the length of the nylon string produced (in meters) using the following equation:

Nylon produced (m) = (test tube diameter (m)) X () X (# test tube revolutions )

Table 25.1

Test tube diameter (mm)

# of test tube revolutions

Length of nylon (m)

SAFETY CONCERNS

CAUTION:All chemicals are hazardous to the skin and eyes. Safety goggles and gloves are required during the experiment!!!

WASTE MANAGEMENT

Pour all waste from synthesis and solubility tests into container labeled “ORGANIC WASTE (Polymers)”

CLEANING

Clean all glassware with soap, water, brush, and rinse with wash acetone before returning to lab drawer!

DO NOT return any glassware to lab drawer dirty or wet!