In our previous article from green chemistry and we talked about the 12 basic principles of green chemistry. Now let's take a brief look at the applications of green chemistry.
We know that many of the manufacturing processes involve chemical reactions and processes, and as we can deduce, it is difficult to imagine how we would survive without the chemical industry. However, unfortunately, the amount of product we obtain in these chemical processes is less than the waste and hazardous materials that emerge -most of the time-. We can eliminate these problems with green chemistry that emerged about 25 years ago.
So how? The answer is very simple. Inspired by nature.
Green Chemistry Applications
The biggest chemical factory is actually nature. Reactions in nature with absolute precision. sustainable way it performs. Natural chemical processes are the best inspiration for us to design and implement environmentally friendly, safer and sustainable synthetic routes (Sharma et al., 2020. A glimpse into green chemistry practices in the pharmaceutical industry.).
With this inspiration, let's look at the solvents that are used in almost all chemical reactions in the first stage and increase the waste generation.
Chemical processes use large amounts of toxic, flammable and volatile organic solvents to prepare chemicals and materials. About 20 million tons of organic solvents are released into the atmosphere each year., which is solvent waste and to environmental pollution leads to Greener solvents such as water, supercritical fluids, ionic liquids, non-toxic liquid polymers and various combinations thereof. Its use in chemical processes has become the main focus of research in academia and industry.
A green solvent must meet some key requirements such as low toxicity, availability and ease of recycling, and high process efficiency. It is known that the effectiveness of a process is often highly dependent on the properties of the solvents used. Due to their special properties and functions, green solvents are used to optimize chemical processes, reduce solvent usage and processing steps, and sustainability (Song et al., 2014. Green chemistry: a tool for the sustainable development of the chemical industry.).
In addition, green solvents have proven to be better than conventional solvents in product separation, isolation and post-production processes. Solvents such as dichloromethane, acetone, and ethyl acetate are interchangeable with biomass-derived solvents such as methyl (2,2 dimethyl-1,3-dioxolan-4-yl) methyl carbonate, methyl tetrahydrofuran (2-MeTHF), and y-valerolactone (GVL). found.
For example, 2-MeTHF has been reported to be a superior solvent in the palladium-catalyzed Suzuki-Miyaura coupling of benzoyl chloride and phenylboronic acid, resulting in lower palladium loading, better yields and excellent product purity. In addition, GVL has been used instead of toxic aprotic solvents such as acetonitrile, dimethylformamide (DMF) and N,N-dimethylacetamide (DMA) in palladium-catalyzed Heck-Mizoroki couplings of iodoarenes with acrylic esters.
These applications have started to be made not only by research groups but also by large companies. For example, Pfizer has published a redesigned synthetic route for the production of sildenafil citrate (viagra), and using this improved method, The use of solvents and hazardous reagents is significantly reduced (Figure 1.)
Figure 1. Traditional and newly developed route for sildenafil citrate (Sharma et al., 2020. A glimpse into green chemistry practices in the pharmaceutical industry)
Catalysis plays a key role in the chemical industry because most chemical processes require catalysts to speed up reactions, increase selectivity, and reduce energy requirements. Existing catalysts often rely on expensive, toxic, harmful or noble metals. Green catalysts should have some common properties such as high activity, selectivity and stability, ease of separation and reuse; They must be based on environmentally safe and widely available raw materials such as abundant metals, organic compounds and enzymes.
The discovery and development of new synthetic pathways and chemical processes is highly dependent on progress in catalysis. Environmental Protection The design and use of green catalysts and catalytic systems is an important task and essential for the sustainability of the chemical industry (Song et al., 2014. Green chemistry: a tool for the sustainable development of the chemical industry.)
To solve the catalyst problem biocatalysis (enzymatic catalysis) It has gained popularity especially in recent years and many studies have been done on this subject. Among the main features of this technology Using water as green reaction medium, better selectivity and no product contamination with trace metals.
For example, the company GlaxoSmithKline (GSK) has reported amide coupling of indazole derivatives. This conversion traditionally involves ester hydrolysis followed by acid activation and nucleophilic attack of the amine. As an alternative approach, however, researchers at GSK were able to achieve their desired product by using the enzyme lipase TL to directly link the amine with the ester to access a valuable API intermediate (Figure 2).
Figure 2. Enzyme-catalyzed amidation (Sharma et al., 2020. A glimpse into green chemistry practices in the pharmaceutical industry.)
Green and Renewable Raw Material
Currently, our energy supply and raw materials for the production of organic chemicals and materials are mainly based on non-renewable and dwindling fossil resources.
Biomass and CO2 comic renewable carbon sources. Its use in the chemical and energy industries is extremely important and different ways and processes have been developed. However, biomass and CO2Thermodynamic, kinetic and technical challenges have been encountered in converting fuels and chemicals. Most existing routes are technically feasible but economically prohibitive and only very small proportions of resources are used at present.
Biomass and CO2The development of efficient methods for converting fuel into useful chemicals and liquid fuels through energetically and economically viable industrial processes is of paramount importance, but is currently challenging.
In addition, greener, cheaper, safer raw materials such as oxygen, hydrogen peroxide and solar energy and sustainable energy sources Studies on its use in chemical processes are also ongoing (Sharma et al., 2020. A glimpse into green chemistry practices in the pharmaceutical industry).
to green chemistry In this transition, especially engineering applications and engineers have a great responsibility. Many existing drugs, fine chemicals, commodity chemicals and polymers are harmful. Products that do not harm human health and the environment should be designed and produced to replace hazardous products.
Clearly, the discovery of synthetic pathways, the design of sustainable products and solvents, and the research of new catalysts and chemical processes are closely related and should be integrated. In addition, economic benefits are the main driver for the development of green chemistry and technology (Sharma et al., 2020. A glimpse into green chemistry practices in the pharmaceutical industry).
If we love our planet, we should turn to green and nature and contribute as much as possible to the studies in this field. Who knows, the ideas that will save the world may have already begun to sprout in the minds of those reading this article.
with love and green thick.