Advertisement
Grab your lab coat. Let's get started
Welcome!
Welcome!
Create an account below to get 6 C&EN articles per month, receive newsletters and more - all free.
It seems this is your first time logging in online. Please enter the following information to continue.
As an ACS member you automatically get access to this site. All we need is few more details to create your reading experience.
Not you? Sign in with a different account.
Not you? Sign in with a different account.
ERROR 1
ERROR 1
ERROR 2
ERROR 2
ERROR 2
ERROR 2
ERROR 2
Password and Confirm password must match.
If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)
ERROR 2
ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.
Supercritical water to recycle plastics
The importance of the need to chemically revamp the recycling of waste plastics was appropriately featured in C&EN’s June 18 issue (page 24). Strangely, the successful use of water alone to cleave the bonds in these and other giant molecules in a matter of seconds was not mentioned.
Of course, the water must be in a supercritical state, when it has remarkable solvent and heat transport properties, as collected by Yizhak Marcus in “Supercritical Water: A Green Solvent; Properties and Uses.” A more recent book is “Hydrothermal and Supercritical Water Processes” by Gerd Brunner.
In addition to the extreme rapidity of the supercritical water reactions, simultaneously hydrogen atoms are provided from the water that stabilize the free radicals in the small molecules created by bond cleavage in the substrate and thereby reduce or eliminate the objectionable char formation of conventional, purely thermal pyrolysis processes.
To take advantage of these unique characteristics, a continuous reactor system is desirable, and a demonstration-sized unit has been constructed and patented (US Patent No. 9932285).
Several industrial companies (Licella, Renmatix, and Xtrudx) are actively involved with high-temperature water, and Massachusetts Institute of Technology has a substantial program under the leadership of professor William H. Green of the chemical engineering department.
Graham Allan
Seattle
Editor’s note: Allan is an inventor on the patent mentioned in the letter and is involved in the company Xtrudx.
Chemical & Engineering News
ISSN 0009-2347
Copyright © 2024 American Chemical Society
The power is now in your (nitrile gloved) hands
Sign up for a free account to get more articles. Or choose the ACS option that’s right for you.
Already have an ACS ID? Log in
Join the conversation
Contact the reporter
Submit a Letter to the Editor for publication
Engage with us on Twitter