It is important to incorporate green chemistry when designing a novel reaction.
12 Principles of Green Chemistry
Learn more at the [US EPA](Basics of Green Chemistry | US EPA an BeyondBenign). University of Toronto has some videos to introduce the concepts:
- Prevention. Preventing waste is better than treating or cleaning up waste after it is created.
- Atom economy. Synthetic methods should try to maximize the incorporation of all materials used in the process into the final product. This means that less waste will be generated as a result.
- Less hazardous chemical syntheses. Synthetic methods should avoid using or generating substances toxic to humans and/or the environment.
- Designing safer chemicals. Chemical products should be designed to achieve their desired function while being as non-toxic as possible.
- Safer solvents and auxiliaries. Auxiliary substances should be avoided wherever possible, and as non-hazardous as possible when they must be used.
- Design for energy efficiency. Energy requirements should be minimized, and processes should be conducted at ambient temperature and pressure whenever possible.
- Use of renewable feedstocks. Whenever it is practical to do so, renewable feedstocks or raw materials are preferable to non-renewable ones.
- Reduce derivatives. Unnecessary generation of derivatives, such as the use of protecting groups, should be minimized or avoided if possible; such steps require additional reagents and may generate additional waste.
- Catalysis. Catalytic reagents that can be used in small quantities to repeat a reaction are superior to stoichiometric reagents (ones that are consumed in a reaction).
- Design for degradation. Chemical products should be designed so that they do not pollute the environment; when their function is complete, they should break down into non-harmful products.
- Real-time analysis for pollution prevention. Analytical methodologies need to be further developed to permit real-time, in-process monitoring and control before hazardous substances form.
- Inherently safer chemistry for accident prevention. Whenever possible, the substances in a process, and the forms of those substances, should be chosen to minimize risks such as explosions, fires, and accidental releases.
Reaction Conditions
Process Mass Intensity Prediction Calculator - Can be used to evaluate a potential reaction, or benchmark the outcome.
Process Mass Intensity Calculator - To benchmark and quantify green improvements.
Convergent Process Mass Intensity Calculator (for convergent processes)
Drug Manufacturing Scorecard calculator
Software to predict reactions
DOZN2.0
DOZN2.0 by MilliporeSigma is a free virtual tool that scores reactions and chemicals according to their environmental health and safety impact. It also offers alternative solutions if your original reaction uses toxic chemicals or is very energy demanding.
IBM RXN
Web-based program that allows chemists at home to just draw molecules and receive information on the resulting chemical reaction or to find the optimal synthetic route from commercial starting materials.
Currently does not currently include Green Chemistry, but after conversations with Green Your Lab has promised to put this into it’s next iteration!
- Was used by Department of Chemistry at St. Edward’s University in Austin Texas to teach Chemistry to students during COVID-19 University shutdown.
- Easy to use graphical interface to draw molecules
- Pre-loaded database of reactions from 25 million patents
- Can submit your own training dataset
- Can interface with commercially available laboratory robotics units. This allows you to take your predicted reaction and test it autonomously using a robot lab unit
Our test
Reaction prediction mode
Mercaptan oxidation - The program very quickly predicted the correct result.
Cyclo-oligomerization of acetylene - The nickel tetracarbonyl catalyst caused an error, and submitting without the catalyst gave the wrong result. In the case without the nickel catalyst, IBM RXN clearly marked out that the prediction is of “low confidence”.
Retosynthesis mode
(users draw the target molecule and the system suggests a synthesis route from commercially available molecules)
Nitrobenzene - IBM RXN provided five synthesis routes with a confidence level of 1 (the highest). Some of these reactions missed critical steps, such as generation of the correct electrophile, so would be unlikely to result in successful synthesis. However, the classic synthesis route using nitric acid and sulfuric acid was one of the top five results.
Ibuprofen (multistep reaction) - Most attempts resulted in errors and none of the predicted routes included the two most common synthesis pathways, Boots or Boots Hoechst Celanese Company. It did provide some other reasonable synthesis suggestions.
Other
For Green Analytical Chemistry, including analytical chromatography, please see this section here.
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