My watch list
my.chemeurope.com  
Login  

Breaking down plastic waste

Organo-ruthenium mediated hydrogenation under mild conditions

30-May-2017

Nagoya University

Design of a sterically confined bipyridine-ruthenium (Ru) framework allows controlled confinement of adsorbed H2 and its delivery to inert amides enabling catalytic hydrogenation of a wide range of amide bonds. Cleavage of both C=O and C-N lactam bonds achieved by activation of a single precatalyst.

What to do proteins and Kevlar have in common? Both feature long chain molecules that are strung together by amide bonds. These strong chemical bonds are also common to many other naturally occurring molecules as well as man-made pharmaceuticals and plastics. Although amide bonds can give great strength to plastics, when it comes to their recycling at a later point, the difficultly of breaking these bonds usually prevents recovery of useful products. Catalysts are widely used in chemistry to help speed up reactions, but breaking the kinds of amide bonds in plastics, such as nylon, and other materials requires harsh conditions and large amounts of energy.

Building on their previous work, a research team at Nagoya University recently developed a series of organometallic ruthenium catalysts to break down even the toughest amide bonds effectively under mild conditions.

"Our previous catalysts could hydrogenate most amide bonds, but the reactions needed a long time at high temperature and high pressure. This new ruthenium catalyst can hydrogenate difficult substrates under much milder conditions," says lead author Takashi Miura.

Hydrogenation is the key step leading to breakdown of amide bonds. The catalyst features a ruthenium atom supported in an organic framework. This ruthenium atom can adsorb hydrogen and deliver it to the amide bond to initiate the breakdown. The team probed the position of hydrogen on the catalyst in the reaction pathway and modified the shape of the supporting framework. By making sure that the hydrogen molecule was is the best possible position for interaction with amide bonds, the team achieved much more effective hydrogenation.

Group leader Susumu Saito says, "The changes we made to the catalyst allowed some tricky amide bonds to be selectively cleaved for the first time. This catalyst has great potential for making designer peptides for pharmaceutics and could also be used to recover materials from waste plastics to help realize an anthropogenic chemical carbon cycle."

Facts, background information, dossiers
  • ruthenium catalysts
  • peptides
  • temperature
  • recycling
More about Nagoya University
  • News

    Flipping the switch on ferroelectrics

    Many next-generation electronic and electro-mechanical device technologies hinge on the development of ferroelectric materials. The unusual crystal structures of these materials have regions in their lattice, or domains, that behave like molecular switches. The alignment of a domain can be ... more

    Turning metal catalysis on its head for a sustainable future

    The uncertain future of oil feedstocks and environmental pressure are forcing the chemical industry to adapt and find new renewable sources to sustain its activities. Biomass from sources including wood, agricultural waste, and even human garbage, represents a widely available renewable fee ... more

    New coating surface for superior rust resistance with 'colorless' color

    Polymer chemists at Nagoya Institute of Technology in Japan invented a novel and simple coating process to color metals, leading to higher performance and saving the energy. The method involves a chemical modification to non-ionic polymers and nanotechnology. Electrophoretic deposition is a ... more

Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE