Patrick Reany
9 May 2024
Preface:
Green Chemistry is that division of actual chemistry that can contribute to cheaper, less toxic means of producing the chemicals we need for coverings, bottles, containers, food additives, and much more. We've only just begun to explore what green chemistry can do for us and for all of God's green earth. We don't have to just accept the status quo. We can do better, people.
This article is a short essay on the book
Green Chemistry, Theory and Practice by Paul Anastas and John Warner, Oxford University Press, New York, 1998.My intension is merely to briefly highlight each chapter. On occasion I asked Copilot to explains certain things to me.
Chapter 1: Introduction:
The first part of this book is dedicated to defining and characterizing green chemistry from within general chemistry. Viewed philosophically, I'd say that the authors want us to agree with their conclusion that green chemistry is the attempt to put into place practical standards for "ethical chemistry," which is to be interpreted in the grandest sense, that we design the safest synthesis pathways that least negatively impacts earth's environments, both as intermediate and end products. And because the earth is a dynamic system, no fouling of the earth in one place will remain local forever.
Green Chemistry involves the design and redesign of chemical syntheses and chemical products to prevent pollution and thereby solve environmental problems. [p. 8-9]Green chemistry is the use of chemical principles and methodologies for source reduction, the most desirable form of pollution prevention. [p. 9]
Chapter 2: What is green chemistry?
This chapter emphasizes the synthesis of chemicals, while emphasizing the toxic intermediate stages of production and the toxicity of the final products for industrial or ordinary use. It doesn't stress the quantity of energy needed to undergo this process, but perhaps it should these days.
Chapter 3: Tools of green chemistry
The selection of a feedstock has a major effect, not only on the efficacy of the synthetic pathway, but also on the environmental and health effects of the process. [p. 21]Currently, the largest feedstock is petroleum.
Chapter 4: Principles of green chemistry
The authors listed twelve principles which they believe should be the foundations to ethical and sustainble green chemnistry. I will list only the first three of them to keep within fair use:
Did you know that supercritical fluids can be used as nontoxic solvents in the chemical synthesis process?
Chapter 5: Evaluating the effects of chemistry
Chapter 6: Evaluating feedstocks and starting materials
The materials we start with need to be chosen carefully, keeoing in mind that some feedstocks will eventually run out.
Chapter 7: Evaluating reaction types
"This section provides some illustrative examples of how one may enhance the evaluation process of a given synthetic scheme beyond these traditional measures to predict some environmental consequences and use this information to design greem chemistry alternatives." (p. 72)
Various alternative reactive processes are discussed, including elimination, pericyclic, and oxidation/reduction reactions. One goal discussed is to "avoid unnecessary redox chemistry."
Chapter 8: Evaluating of methods to design safer chemicals
This chapter emphasizes how to make the desired end product, while minimizing its toxicity and bioavailability.
According to Wikipedia: In pharmacology, bioavailability is a subcategory of absorption and is the fraction (%) of an administered drug that reaches the systemic circulation.
Chapter 9: Examples of green chemistry
This chapter is this book's deepest dive yet into specific organic molecular reactions. Polymers and glucose make for good feedstocks in the green laboratory. Supercritical CO2 can be used as a replacement for organic solvents.
Chapter 10: Future trends in green chemistry
"Since the chemical industry currently relies almost exclusively on petroleum-based feedstocks, which are of course in their nearly fully reduced state, it is oxidation chemistry that allows these feedstocks to become the chemical products ultimately used by the consumer." [p. 115]
I presented the above quote to Copilot for it to explain this bit of redox chemistry to me, saying, Please explain to me what is meant by the following [above] quote from a book on green chemistry (emphasizing the oxidation of reduced feedstocks by oxidation chemistry).
Copilot:
Certainly! Let's break down the quote and explore its meaning:
1. Feedstocks:
- Feedstocks are the main ingredients used in the production of chemical products. They serve as the starting materials for chemical synthesis.
- In the context of green chemistry, feedstocks play a crucial role, and there are different types of feedstocks:
- Depleting Resources: These include non-renewable resources like petroleum. The environmental impact of obtaining such feedstocks must be considered.
- Recycled Materials: Using recycled materials as feedstocks is preferable from a sustainability standpoint, but their availability is limited.
- Renewable Resources: These are materials obtained from sources like photosynthesis and biological processes [1].
2. Reduced State of Petroleum-Based Feedstocks:
- Petroleum-based feedstocks (such as crude oil) are primarily composed of hydrocarbon molecules.
- These hydrocarbons are in a highly reduced chemical state because they contain a large number of hydrogen atoms relative to their carbon atoms.
- In other words, they have a high hydrogen-to-carbon ratio, which makes them fully or nearly fully reduced.
3. Oxidation Chemistry:
- Oxidation chemistry involves the process of adding oxygen or removing electrons from a substance.
- When applied to feedstocks, oxidation chemistry allows these highly reduced hydrocarbons to be transformed into chemical products.
- By introducing oxygen or removing electrons, the feedstocks undergo chemical reactions that lead to the formation of more complex molecules.
4. Role of Oxidation Chemistry:
- Since the chemical industry heavily relies on petroleum-based feedstocks, oxidation chemistry is essential.
- Through oxidation reactions, these feedstocks can be converted into various chemical products that are ultimately used by consumers.
- Examples include the production of polymers, plastics, synthetic rubber, and other chemicals derived from petroleum-based feedstocks.
In summary, oxidation chemistry plays a critical role in transforming reduced feedstocks (such as petroleum) into the diverse range of chemical products we use in our daily lives [1]. By harnessing oxidation reactions, the chemical industry can create valuable materials from these raw ingredients.
If you'd like to explore more about sustainable feedstocks and their impact on the chemical industry, I recommend checking out additional resources on this topic [2,3].
Source: Conversation with Bing, 5/8/2024
(1) 13.15: Feedstocks and Reagents - Chemistry LibreTexts.
https://chem.libretexts.org/Bookshelves/Environmental_Chemistry/Green_Chemistry_and_the_Ten_Commandments_of_Sustainability_%28Manahan%29/13%3A_The_Anthrosphere_Industrial_Ecology_and_Green_Chemistry/13.15%3A_Feedstocks_and_Reagents.
(2) Sustainable feedstocks in chemicals | McKinsey. https://www.mckinsey.com/industries/chemicals/our-insights/sustainable-feedstocks-accelerating-recarbonization-in-chemicals.
(3) A Comprehensive Review of Feedstocks as Sustainable ... - Springer. https://link.springer.com/article/10.1007/s12155-022-10440-2.
(4) RENEWABLE FEEDSTOCKS - Green Chemistry Toolkit. https://greenchemistry-toolkit.org/wp-content/uploads/2020/07/GC-4-Day_Training-Day-2-03-Feedstocks-Presentation-LU.pdf.
My last comment on this chapter is from p. 116, which states that the goal of green chemistry during the oxidation phase needs to be cataclytic rather than stoichiometric.
Lastly, I asked Copilot this request: Please explain this addendum to the previous quote: The goal of green chemistry during the oxidation phase needs to be catalytic rather than stoichiometric.
Copilot:
Certainly! Let's dive into the concept of catalytic versus stoichiometric reactions in the context of green chemistry during the oxidation phase:
1. Stoichiometric Reactions:
- In stoichiometric reactions, reactants combine in fixed ratios according to their chemical equations.
- The term "stoichiometry" refers to the quantitative relationship between reactants and products in a chemical reaction.
- For example, consider the combustion of methane (CH4) with oxygen (O2):
CH4 + 2O2 -> CO2 + 2H2O
- In this balanced equation, the stoichiometric ratio is 1:2:1:2 for CH4, O2, CO2, and H2O, respectively.
- Stoichiometric reactions often require precise amounts of reactants, and any excess reactants are typically wasted.
2. Catalytic Reactions:
- Catalytic reactions involve the use of a catalyst -- a substance that accelerates a chemical reaction without being consumed.
- The catalyst provides an alternative reaction pathway with lower activation energy, allowing the reaction to proceed more efficiently.
- Unlike stoichiometric reactions, catalytic reactions do not follow strict stoichiometric ratios.
- Catalysts enable the transformation of reactants into products while remaining unchanged themselves.
- For example, consider the oxidation of alcohols to aldehydes or ketones using a palladium catalyst:
R-CH2OH + O2 \xrightarrow{\text{Pd catalyst}} R-C(=O)-H + H2O
- Here, the palladium catalyst facilitates the oxidation of the alcohol group (R-CH2OH) to the carbonyl group (R-C(=O)-H).
3. Green Chemistry and Catalysis:
- Green chemistry aims to minimize the environmental impact of chemical processes.
- During the oxidation phase, green chemistry advocates for catalytic reactions over stoichiometric ones.
- Why?
- Efficiency: Catalytic reactions reduce waste by allowing lower reactant quantities.
- Resource Conservation: Catalysts can be reused, minimizing the need for excess reactants.
- Reduced Energy Requirements: Lower activation energy means less energy input.
- Environmental Benefits: Fewer byproducts and less pollution.
- By emphasizing catalysis, green chemistry promotes sustainable and eco-friendly chemical transformations.
In summary, the goal of green chemistry during the oxidation phase is to favor catalytic reactions over stoichiometric ones. Catalysis offers efficiency, resource conservation, and environmental benefits, aligning with the principles of sustainable chemistry.
Where to recycle electronic components in your area:
Links provided "as is," but not vetted by me. Follow safety precautions if the device has a lithium battery in it.
Of interest is the toxicity to humans, wildlife, and the local and global effects.
Recycling Page:
Facts and Definitions:
Fact: The world currently creates about 2 billion tons of trash every year, and that is projected to go even higher if we don't do something about it.
Fact: One person's trash is another person's valuable raw material.
Fact: Polyester is a non-natural material made primarily from petroleum-based raw materials.
Fact: By the year 2000, polyester was used in fabrics more than was cotton, and it has grown in percentage ever since.
Definition: Biowaste -- waste in the form of organic matter, such as manure, wood cuttings, etc..
Definition: Bio-plastics -- plastics made more of biological materials, than of petroleum.
Definition: Upcycling -- making use of a waste product that would otherwise be taken to a landfill, converting it into a product of higher value than the original.
Definition: Greenwashing -- According to Wikipedia, Greenwashing (a compound word modeled on "whitewash"), also called green sheen, is a form of advertising or marketing spin in which green PR and green marketing are deceptively used to persuade the public that an organization's products, aims, and policies are environmentally friendly.
Definition: Reduce -- this is a term I'm stipulating to mean 'to break down into simpler components'.
Definition: Recyc -- a recyclable material or object.
Definition: E-waste -- electronic waste.
Definition: Green chemistry -- similar to sustainable chemistry or circular chemistry,[1] is an area of chemistry and chemical engineering focused on the design of products and processes that minimize or eliminate the use and generation of hazardous substances -- electronic waste. [Source: Wikipedia]
Definition: VOCs -- volatile organic compounds. As many as 10,000 chemical could be so classified. GreenGuard and GreenSeal might be able to recommend what products are safest from the measure of off-gassing VOCs.
Sequestering CO2 from burning waste:
The Beauty of Green Chemistry | Heidi Bialk | TEDxBoston TEDx Talks [5:29 min]. Intro talk on the subject.
There are journals dedicated to green chemistry.
What is Green Chemistry? Michigan EGLE [1:45 min]. Intro talk on the subject.
The Green Chemistry Revolution | Volvo Environment Prize 2021 Volvo Environment [10:32 min]. Intro talk on the subject.
M1A MoDRN Introduction: "Why Green Chemistry?" Yale Courses [7:31 min] Intro to the series. There are follow-up YouTube videos expanding on this topic, if you're interested. See the description.
EPA Green Chemistry US Environment [6:21 min] Green chemistry is the design of chemical products and processes that reduce or eliminate the use or generation of hazardous substances.
Green Chemistry - Principle 1 | Environmental Chemistry | Chemistry | FuseSchool US Environment [2:23 min] This first video of a multipart series.
Green chemistry | Sustainable Energy CNBC International Chemistry [24:51 min] Business and science. Green stands for eco-friendly, the US dollar, and a new and fresh approach to industrial chemistry. Microbes make gold from waste e-boards. Urban mining. Paul Anastas, Yale University, Center for Green Chemistry.
Why This Ultra Dense Battery Breakthrough Matters Undecided with Mike Fareell [16:07 min] DAC = Direct air capture. Switchgrass. Pyrolysis. Biochar.
The Reality of Carbon Capture Yale Center for Green Chemistry [2:07 min] Main idea: Solvents dissolve things to be taken away or to allow for even mixing. Safer green solvents, and some processes can be reconstructed to do without the need for solvents.
French startup uses plastic-chewing enzymes in 'closed-loop' recycling FRANCE 24 English [6:54 min]
Green Chemistry: In conversation with Professor John Warner on creating a sustainable future. Monash University Faculty of Science [17:49 min]
Making Cyrene: the Next Common Solvent? Chemiolis [10:20 min]
Dissolving cotton, paper and wood cellulose with a green solvent Sasarello [4:55 min] The Lyocell Process. Journal BioResources.
Making Polymers and Materials From Waste Biomass and Carbon Dioxide Green chemistry. [1:04:26 time]. Brandon University Science Seminar. A lot of information in the description. (Quite recent.)