Chemistry World Blog

— coke-bottle

Well, when I say green, I mean in the environmental sense – not in the ‘lets have a green coloured glass of Coca-Cola’ sense!

Basically, The Coca-Cola Company is to start a pilot launch of a new, fully recyclable poly(ethylene terephthalate) (PET) plastic bottle that is from a blend of petrochemical and up to 30 per cent plant-derived materials.

‘The ‘PlantBottle’ is a significant development in sustainable packaging innovation,” says Muhtar Kent, Coca-Cola’s chief executive. ‘It builds on our legacy of environmental ingenuity and sets the course for us to realize our vision to eventually introduce bottles made with materials that are 100 percent recyclable and renewable.’

— pet

A quick google search will show you that PET is made by polymerising monomers of ethylene terephalate. These monomers are made in one of two ways: either by an esterification reaction between terephthalic acid and ethylene glycol; or by transesterification reaction between ethylene glycol and dimethyl terephthalate.

Now comes the ‘green’ part of the tale, which is that some of the ethylene glycol that Coca-Cola has started to use is actually being made from sugar cane and molasses – a byproduct of sugar production.

According to the company’s press release, a study conducted at Imperial College London, UK, indicated that by using 30 per cent plant-based materials to make the bottle would reduce the carbon footprint of each bottle by up to 25 per cent.

So just one question remains – once all of Coca-Cola’s bottles are made from biofeedstocks will there be enough sugar left to make the Coca-Cola itself?

Matt Wilkinson