Opportunities for recycling plastic scrap offered by hydroformylation chemistry

Researchers at the University of Wisconsin–Madison have found a way to reduce emissions by 60% during the chemical recycling of low-value plastic scrap.

They have fine-tuned existing treatments for recovering olefins from pyrolysis oil by using a ‘much less energy-intensive’ process called homogenous hydroformylation catalysis.

The new method, published in the journal Science, could increase the economic incentives for chemical recycling and open a door to recycling new types of plastic, according to Professor George Huber who heads the R&D project.

The UW–Madison team converts olefins into aldehydes, which can then be further reduced into important industrial alcohols. The output includes ingredients used to make soaps and cleaners, as well as other ‘more useful’ polymers.

‘We’re really excited about the implications of this technology,’ says Huber. ‘It’s a platform technology to upgrade plastic waste using hydroformylation chemistry.’

He says a major benefit is that the recycling industry could adopt the process in the short term. At least 10 large chemical companies have built or announced plans for facilities to produce pyrolysis oils from waste plastics and Huber notes many run the oil through steam crackers to produce low-value compounds. The new chemical recycling technique could provide a more sustainable and lucrative way to use those oils.

‘Currently, these companies don’t have a really good approach to upgrade the pyrolysis oil,’ says postdoctoral researcher Houqian  Li. ‘In this case, we can get high-value alcohols worth up to US$ 6 000 (EUR 5 480) per tonne from waste plastics which are only worth about US$ 100.’

The new method is ‘relatively easy’ to scale up as it uses existing technology and techniques.