Environment

Can tires be made from grass and trees?

Can tires be made from grass a...
The researchers say the discovery gives the prospect of renewable isoprene a real boost 
The researchers say the discovery gives the prospect of renewable isoprene a real boost 
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The researchers say the discovery gives the prospect of renewable isoprene a real boost 
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The researchers say the discovery gives the prospect of renewable isoprene a real boost 
The chemical process combines the boosting of natural microbial fermentation with catalytic refining
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The chemical process combines the boosting of natural microbial fermentation with catalytic refining

Tires are dirty business, and we're not just talking about the mud they gather as they roll beneath your car. Manufacturing rubber is a resource-intensive process that is heavily reliant on petroleum, but now scientists are claiming a chemical breakthrough that replaces the key molecule in conventional tires with one sourced from grass and trees instead, all without affecting the tire's color, shape or performance.

The environmental impact of tire production has prompted a years-long search for a more sustainable method. These efforts have focused on the main component of rubber, a molecule called isoprene. To make isoprene, molecules in petroleum are thermally broken apart and the molecule is isolated from hundreds of other chemicals and purified, at which point it organizes itself into long polymer chains.

Conveniently, isoprene can also be derived from natural sources. While researchers have explored the possibility of using sugars derived from biomass to make tire rubber, doing so on anything near the scale required is no easy feat. In 2010, for example, Goodyear described a method of engineering bacteria to ramp up the microbial production of isoprene, while the cloning of a key enzyme to produce man-made isoprene in 2012 offered yet another potential way forward.

Now researchers at the University of Minnesota are claiming a new breakthrough in the area, by way of a chemical process that combines the boosting of natural microbial fermentation with catalytic refining, similar to the process used to refine petroleum.

The chemical process combines the boosting of natural microbial fermentation with catalytic refining
The chemical process combines the boosting of natural microbial fermentation with catalytic refining

It begins with the microbial fermentation of plant sugars, such as glucose, into something called itaconic acid. This acid is then mixed with hydrogen, causing a chemical reaction that results in something called methyl-THF.

And the third step, which is where the breakthrough lies, involves using a recently discovered catalyst called Phosphorous Self-Pillared Pentasil to dehydrate the methyl-THF into isoprene. This method resulted in catalytic efficiency as high as 90 percent, with most of the product being isoprene, something the researchers say gives the prospect of renewable isoprene a real boost and could even lead to other advanced rubber-based products.

"The performance of the new P-containing zeolite catalysts such as S-PPP was surprising," says Paul Dauenhauer, a University of Minnesota associate professor of chemical engineering and lead author of the new study. "This new class of solid acid catalysts exhibits dramatically improved catalytic efficiency and is the reason renewable isoprene is possible."

The research was published in the journal ACS Catalysis.

Source: University of Minnesota

4 comments
Bob Flint
Rubber trees are they actually plants??
VincentWolf
Wood is an amazing material that hasn't gotten nearly enough attention. For example, by messing with the alpha beta bonds of cellulose you can turn wood directly into an oil for producing gasoline. The trick is making intermediates of acid esters via acetylation processes. I researched this in 79' and it was my senior thesis. Almost worked, needed more time!
Nik
Denuding the planet of its greenery, for things like tyres, is likely to be more damaging than using fossil fuels, to make them. Greenery cools the atmosphere, provides food, and, oxygen! It would be more useful if a more effective way of recycling rubber tyres could be found, given that currently, approximately 290 million old tires are disposed of every year, and 55 million used tires, give or take, are illegally dumped in landfills, on someone else's private property or just thrown away on roadsides. Recovering the ''key element'' from used tyres would solve two problems simultaneously, that of sourcing the material, and disposal of the old tyre. Also, given the literal mountains of old tyres stacked around the world, the material source is readily available, and will require no new sourcing.
Douglas Bennett Rogers
Vegetation warms the Earth so it can survive by pumping water from the ground into the atmosphere. It also frees oxygen by sequestering carbon but this is a much weaker effect than the humidification. Ice ages are always associated with desertification.