6BL - Experiment 10B: Multistep Synthesis of Nylon- 6,6 from Cyclohexene

Purpose

-to synthesize the polymer Nylon-6,6 from the readily available starting material cyclohexene

Why do we need excess hydrogen peroxide but not Aliquat 336?

Aliquat 336 transfers the Tungstate from the aqueous layer and into the organic layer where cyclohexene is. As the cyclohexene is turned into adipic acid, tungstate is reduced and returns back to the aqueous layer, where it is oxidized by hydrogen peroxide to be able to keep catalyzing the reaction. However, hydrogen peroxide does not regenerate like Tungstate and turns into water instead. This is why excess hydrogen peroxide is needed.

How can you ID if a Nylon is made from on or two monomers?

Nylon 6 vs Nylon-6,6

What makes nylon good for the above materials?

Nylon is versatile and tolerant of many different mechanical and thermal stresses

What is the final product?

Nylon-6,6 polyamide

How are polymers made in step growth polymerization (condensation polymers)?

Polymers made by this method are assembled from monomers that have a reactive functional group at each end of the polymer unit. Thus chains can grow by addition of monomers (one unit), dimers (two monomer units), or oligomers (multiple monomer units) -made by linking monomers as a result of removing (in most cases) a small molecule, generating water or alcohol

What does the more reactive acid chloride species allow?

The more reactive acid chloride species allows the polymerization to happen at a faster rate and at room temperature

What is Le Chatlier's principle?

When a system experiences a disturbance (concentration, temperature, pressure changes) it will respond to restore a new equilibrium state. Example, if more reactants are added to the system, Le Chatlier's principle predicts that the reaction will generate more products to offset the change and restore equilibrium

Since adipoyl chloride was so reactive, what method had to be used and why?

a method named unstirred interfacial polymerization is used, which provides a controlled reaction that will not disturb the interface of the reaction and cause the nylon to polymerize into ball

What is Aliquat 336?

a phase transfer catalyst

Why is interfacial polymerization beneficial?

can be sued to achieve a rapid and controlled polymerization because of the fast reaction rate

In what products is nylon found in?

clothing,rope, tents, toothbrush bristles, and automobile nd aircraft materials

What is the limiting reagent?

diamine monomers

What is normal polymerization reaction like?

difficult to control as it is fast, irreversible, and highly exothermic

What does nylon polymerization with an acid chloride instead of the corresponding carboxylic acid do?

greatly reduces the temperature at which this polymerization takes place and increases the reaction rate

Why was an acid chloride used instead of the corresponding carboxylic acid?

greatly reduces the temperature at which this polymerization takes place and increases the reaction rate

oxidizer - oxidizing agent

has the ability to oxidize other substances - causes them to lose electrons

Safety: Aliquat 336 is an _______________ and skin contact should be avoided

irritant

Safety: sodium tungstate is an ____________ and ______________. Must be kept away from ________

irritant, lachrymator (irritates eyes and causes tears to flow)

Why are Low concentrations of both reagents crucial for this reaction?

is important to keep a controlled reaction

What is the reaction state of the third phase?

ocurs at room temperature and low concentration

Safety: 30% hydrogen peroxide is an ___________, _____________, and can cause sever damage to skin and eyes. gloves should be worn throughout the experiment

oxidizer, corrosive

What is interfacial polymerization?

polymerization occurs at an interface between an aqueous solution containing one monomer and an organic solution containing a second monomer

Nylon is a polyamide polymer made by _____________________

step growth polymerization

What is the full name of the reaction taking place in the third transformation?

step growth unstirred interfacial polymerization

Why is there no need to ensure correct stoicheometry in this experiment?

stoicheometry is controlled at the interface as a result of diffusion and the removal of the polyamide products

Safety: hydrochloric acid is a _______ and _________ acid

strong, corrosive

What is the second transformation of the multi-step preparation of Nylon-6,6?

the conversion of adipic acid into adipoyl chloride, which involves the catalytic amount of dimethylformamide solvent to react with oxalyl chloride to form the active Vislmeier chlorinating agent. This active species allows the conversion of the carboxylic acid to the corresponding acid chloride

What is the first transformation of the multi-step preparation of Nylon-6,6?

the oxidation of cyclohexene to adipic acid using using sodium tungstate

What is the third transformation of the multi-step preparation of Nylon-6,6?

the polymerization of the hexamethylenediamine with the adipoyl chloride

What is the purpose of Aliquat 336?

transfer the tungstate from the aqueous layer to the organic phase, which speeds up the reaction by bringing the two necessary compounds into the same phase where they can react

What is happening in the process of polymerization?

when the polyamide strand is pulled, the diamine monomer reacts to form a bond with a diacid chloride terminus and the process repeats. As the strand is pulled, the product is removed causing the monomers in solution to diffuse so that there are units at or near the polymerization site until one of the monomers is no longer available