[Capitalmind]

Hi all, I'm preparing to experiment with alkaline hydrolysis of polyethylene terephthalate largely using NaOH in a solution at around 100 celcius. Sodium Hydroxide (Lye, Caustic Soda) is dangerous and I don't fancy any Fight Club style burns. What types of gloves and neutralizing options are there both in handling and disposing of waste solution?

[Corribus]

It kind of depends on the amount you are planning on using.  White vinegar will work fine as a neutralizing agent, but if you've got a lot of concentrated NaOH to neutralize, you may want to use a stronger acid if you can find one.  Once the base is neutralized, you can probably just pour the waste down the drain, assuming of course there was nothing else in the waste but NaOH and your neutralizing acid.  If you've got other stuff dissolved in there, you will need to check local rules about chemical waste disposal.

As far as safety, good quality rubber gloves will be acceptable for handling concentrated NaOH solutions. I'm talking about the kinds that are made for handling strong acids and bases, not surgical gloves here.  You can usually get them at a hardware store - just ask for the kind you'd use to handle battery acid, that kind of thing. Safety goggles are highly recommended as well - strong base in eye is no fun.  And don't rely on regular glasses either. I splashed drops of base bath on my glasses once and it ate through the coating.  That was an expensive mistake.

Also: find yourself a lab coat.  Lab coat, goggles, thick rubber gloves, all necessary for handling large volumes of strong acids and/or bases.

[Archer]

Talk us through your proposed methodology.

[Capitalmind]

Hydrolysis of PET resin in NaOH solution

To a 10% NaOH solution in 100 ml mixed solvent of ethanol and water (20:80) in a 300 ml flask, add 2g PET resin and heat the flask to 110C for 0.5 hr.

Unreacted residue to be filtered (unsure how) and the filtrate to be acidified by 20% hydrochloric acid to give a solution with white solids. White solids separated by filtration (unsure how) to be washed with water, dried, and identified by IR and melting point measurements to determine terephthalic acid (TPA) purity and yeild, expecting an optimum yield of around 89%.