Monsanto: Alternative route to popular herbicide Roundup®

Additional Information

Roundup® is a widely used weed killer (or "herbicide"). It is very effective because it kills the roots, not just the green part. It also sticks to soil particles, so once in the ground does not affect other plants, and degrades fairly rapidly.

The method originally used to make Roundup® involved first making an intermediate, and then converting this to the product. Unfortunately there are three main concerns associated with this process:

  • Extremely toxic hydrogen cyanide is used
  • Cyanide-containing waste is produced
  • The reaction is exothermic - it produces heat, which must be removed

Monsanto, the company that makes Roundup® has developed, and is now using, a much safer manufacturing route. It uses a different, much less toxic starting material. The reaction also takes fewer steps, making it simpler and cheaper.

This table compares the two processes:

Old process New process
Uses hydrogen cyanide, which is extremely toxic - Just 300 parts per million of hydrogen cyanide in air will kill a person in a few minutes! It is a risk to workers and to those living nearby Starts with a much safer chemical, and does not use hydrogen cyanide at all. Reaction brought about using a copper catalyst
1kg of waste is generated for every 7kg of product, and it must be treated to remove toxic cyanide It is "zero waste", as all the starting materials end up in the product. The catalyst can be used again.
The reaction is exothermic (it gets very hot). If there is a problem and the heat cannot be removed, a dangerous "runaway reaction" (uncontrollable reaction) could occur. The reaction is endothermic (it gets colder if it is not heated). There is not possibility of a runaway reaction.

diagram: old method - new method

The new process is much safer for everyone