Green Chemistry Blog

Over the past 25 years, Green Chemistry has provided a unique forum for the publication of innovative research on the development of alternative sustainable technologies, efficient utilisation of resources and the concomitant minimisation of waste. We are delighted to bring together a very special issue containing articles by members of the green chemistry community as well as past and present Green Chemistry Board members, to mark and celebrate our first 25 years.

Among the contributions to this themed collection is a Paper on the production of low-cost high-quality carbon fiber using lignin alone without chemical treatment or additives (DOI: 10.1039/D3GC04288J).

Read our interview with Xianglan Bai, the corresponding author.

Could you briefly explain the focus of your article to the non-specialist

Low-cost green carbon fiber is of great interest due to its ability to improve material performance and decarbonize industries. For example, broader applications of low-cost carbon fiber in the automobile industry can improve fuel efficiency and reduce carbon emissions from the transportation sector. The US Department of Energy (DOE) stated in the early 2000s that carbon fiber with a tensile strength of 1.72 GPa and tensile modulus of 172 GPa at costs below $5-7/lb can be widely used in the automobile industries. Although lignin has been considered the most promising low-cost green precursor of carbon fiber, the major bottleneck and barrier in developing commercially relevant lignin-based carbon fibers is their poor mechanical properties far below the commercial petroleum-based carbon fibers. Previous approaches of chemically modifying lignin or processing lignin and co-precursors were ineffective in meeting the cost and property requirements of carbon fiber. We recently discovered a surprisingly simple and low-cost method to improve the tensile properties of lignin-based carbon fiber.  By integrating thermal heating and tension stretching during the carbon fiber processing, we successfully manipulated the intrinsic lignin chemistry and controlled material transformation. Our melt-spun carbon fiber made of unmodified raw lignin achieved unprecedented mechanical properties compared to previous lignin-based carbon fiber (tensile strength of 2.45 GPa and tensile modulus of 236 GPa). Its production cost was only $4.17/lb, suggesting its promising economic potential.

How would you set this article in a wider context?

In addition to traditional pulping industries, lignin is increasingly available as a low-cost byproduct from emerging biorefineries. Developing lignin-based high-value products with market-comparable scale holds the key to the economic sustainability of biorefineries. Lignin-based green carbon fiber can be attractive due to its enormous potential markets, such as the automobile and construction industries. However, previous approaches for producing lignin-based carbon fiber have been mostly unsuccessful due to the poor properties of the resultant carbon fibers. Thanks to the thermo-mechanochemistry of lignin discovered in our recent work, 100% lignin-based carbon fibers meeting the automobile-grade properties and cost requirements were achieved by simply controlling heat and tension applied during carbon fiber processing. The discovery of the novel chemistry of lignin and our proof-of-concept results will alter perceptions of lignin-based carbon fibers as the commercially viable low-cost green carbon fibers, therefore advancing lignin valorization in biorefineries.

What is the motivation behind this work?

Polyacrylonitrile, the standard carbon fiber precursor, has one dimensional repeated polymer structure. During its stabilization and carbonization process, the well-defined structure of polyacrylonitrile transforms into a highly oriented turbostratic graphene structure that offers exceptionally high mechanical properties. In comparison, lignin is an amorphous polymer with three-dimensional crosslinked network. During the conventional stabilization and carbonization process, the non-oriented lignin structure turns into an amorphous carbon structure with pores, which leads to poor mechanical properties. Because the intrinsic lignin structure lacking in molecular orientation is responsible for the poor mechanical properties of lignin-based carbon fiber, previous approaches mainly focused on chemically modifying lignin or blending lignin with other polymers or additives with well-defined linear structures. However, such efforts for modifying precursors were insufficient to overcome the tensile property issues of the carbon fiber.

Lignin undergoes extensive chemical transformation and microstructural changes during the thermal treatments required for producing carbon fiber. Thus, it may be possible to alter the chemical reactions of lignin and microstructural evolution through controlling the fiber processing conditions. However, this potential opportunity for modifying lignin has been largely overlooked. In previous studies, lignin-based precursors were oxidized and carbonized using empirical methods or the method initially developed for petroleum-based precursors. To address the knowledge gap, we carefully tracked the chemical structure and corresponding microstructural formation through various stages of fiber fabrication under different thermal and tension conditions. As a result, we found that combining proper thermal treatment and strong tension stretching of the fiber can manipulate chemical reactions and control the microstructure evolution, transforming lignin into oriented and graphene carbons at a surprisingly low temperature of 700 ℃. Based on our patent-pending fiber processing method tailored for lignin, high-quality carbon fiber can be obtained without needing costly co-precursors or chemical treatment.

What aspects of this work are you most excited about at the moment and what do you find most challenging about it?

The discovery of lignin’s thermo-mechanochemistry in our work will provide many exciting opportunities for converting lignin into interesting and higher-value products. Thermo-mechanochemistry is a new terminology our group invented for lignin, which was previously unknown. Since lignin structure depends on parent biomass origin and lignin extraction methods, more research is required to fully understand this new chemistry of lignin. Combining advanced analytical techniques and computational studies will help understand a novel material chemistry.

What is the next step? What work is planned?

We plan to expand our current research to investigate broader types of lignin. We will improve our understanding of lignin’s thermo-mechanochemistry by developing the structure-process-property relationships for different lignin and precursors. We will also continue to improve our methods to increase the mechanical properties of the carbon fiber and reduce production costs. We hope to collaborate with industries to demonstrate our carbon fiber processing method in scale and utilize lignin produced from different industrial processes.

Please describe your journey to becoming part of the Green Chemistry community

I began my academic career as an assistant professor at Iowa State University in 2013. Since then, the overarching goal of my research group has been developing environmentally friendly and transformative technologies to valorize low-cost, abundant resources. Over the years, our group has developed broader expertise in thermochemical conversion, electrified conversion, and material synthesis to convert biomass, waste plastics, and greenhouse gases into fuels, chemicals, and carbon materials. Studying various technologies and feedstocks allowed us to gain expertise in developing integrated processes and multidisciplinary approaches for solving challenging problems in sustainability. In this work, we combined our knowledge of lignin chemistry and material science to investigate lignin-based carbon fiber, which led to the discovery of a novel material chemistry and a new lignin-tailored process for carbon fiber production.

Why did you choose to publish in Green Chemistry?

Green Chemistry is known for publishing high-quality frontier research on various sustainability topics. In this context, Green Chemistry has always been among the top choices to publish our research. Our group has a long history of publishing in Green Chemistry.

What do you think the Green Chemistry journal has done well in the past 25 years, and what do you think are the main challenges our community will face in the next 25 years?

Green Chemistry journal has been widely recognized as one of the top journals in sustainability research. The journal has published many exciting and groundbreaking research. As environmental and energy issues remain grand challenges for our society, there is no doubt that Green Chemistry will continue to serve as an important platform for communicating scientific discoveries in the broader realms of sustainability. In terms of future challenges, improving the transformative aspect of the research findings to demonstrate technologies in scale and developing system approaches is strongly desired for the novel research to make a real-world impact.

Meet the corresponding author

Xianglan Bai is currently a Professor of Mechanical Engineering at Iowa State University. She is also a courtesy professor of Chemical and Biological Engineering at the same institution. She is the Editorial Board Member of Fuel Processing Technology and Carbon Neutrality. The focus of her research group is the valorization of biomass and waste plastics into fuels, chemicals, and carbon-based materials via developing novel thermochemical conversion, electrified conversion (non-thermal plasma and joule heating), and material synthesis.

Over the past 25 years, Green Chemistry has provided a unique forum for the publication of innovative research on the development of alternative sustainable technologies, efficient utilisation of resources and the concomitant minimisation of waste. We are delighted to bring together a very special collection containing articles by members of the green chemistry community as well as past and present Green Chemistry Board members, to mark and celebrate our first 25 years.

Among the contributions to this themed collection is a Perspective on the 10 years of the Green Chemistry Commitment at Beyond Benign (DOI: 10.1039/D4GC00575A).

Read our interview with Amy Cannon and Juliana Vidal, two of the authors

Could you briefly explain the focus of your article to the non-specialist?

Beyond Benign is a non-profit organization passionate and dedicated to empowering the entire chemistry community to achieve a sustainable future through education. To catalyze the reach and depth of this support in higher education, Beyond Benign created and launched the Green Chemistry Commitment (GCC) program in 2013, a voluntary and non-prescriptive promise from colleges, universities, and institutes worldwide to incorporate green chemistry into their curriculum.

How would you set this article in a wider context?

Education in green chemistry is the fundamental piece to the achievement of a sustainable future since it can give current and future scientists the skills to design products and processes with human health and the environment in mind. Through the GCC program, entire higher education institutions have become part of a collective voice that believes in and works together towards a better planet for this and the generations to come. The green chemistry adoption approaches pursued by more than 150 institutions participating in the GCC reflect the diversity of cultures, resources, locations, and individuals within the community and their impact on over 3,300 faculty members and 840,000 students annually. Since publication, this community has grown to over 215 institutions and 5,000 faculty members reaching over 1.2 million students annually.

What is the motivation behind this work?

Together, we are stronger. Regardless of the approach taken or resources used, the green chemistry community is created and maintained by inspiring individuals who are constantly defying the status quo to achieve systemic change locally and globally. This article is a celebration of all the collective efforts taken to promote this meaningful and impactful change, as well as a recognition of the remarkable work performed in the last 10 years by the institutions participating in the GCC community.

What aspects of this work are you most excited about at the moment and what do you find most challenging about it?

It is very exciting to see the increasing number of colleges, institutes, and universities joining the GCC program, as well as their unique institutional journeys to green chemistry integration, adoption, and dissemination. It is also encouraging to see the green chemistry path of our community members and watch some of them become leaders in the field, acting as ‘agents of change’ to further inspire the adoption of sustainable practices regardless of their environments, locations, and roles. Although several milestones have been achieved in these 10 years of the GCC program, the most challenging aspect is and will always be the resistance to change. Adding ‘something new’ to an already jam-packed curriculum can bring a certain level of discomfort and a sense of control loss to some institutions and individuals regarding the inclusion of green chemistry topics in undergraduate and graduate courses. However, teaching and practicing the traditional chemistry concepts ‘through the lens of green chemistry’ can go a long way and promote impactful incremental changes that could inspire a whole generation of future scientists to think about human health and the environment during their molecular design.

What is the next step? What work is planned? 

The ultimate goal of the GCC program is to host a community of transformation around green chemistry, where the individuals in the participant institutions can promote a revolutionary education reform through the living and interdisciplinary integration of green chemistry and sustainability. To do so, the next step of the GCC is to enhance the support of its current signers through grants, professional development, mentoring, and leadership opportunities, as well as increasing the number of institutions in the program. Through an empowered community of transformation, green chemistry can finally achieve its goal of becoming ‘just chemistry’ and the inherent way molecular designers create benign building blocks for products used by our society every day.

Please describe your journey to becoming part of the Green Chemistry community.

Amy Cannon: I was very passionate about sustainability at an early age, but didn’t know how to apply that passion. I studied chemistry in undergrad and was going to use my chemistry skills to study environmental problems. I applied to graduate programs and was admitted to a multi-disciplinary program at the University of Massachusetts in Boston that was focused on environmental sciences. I was assigned an advisor from the chemistry department due to my chemistry background. That advisor was Dr John Warner. Once I learned about green chemistry from him, I quickly turned back to a chemistry major and helped to create the world’s first Ph.D. program in green chemistry. I was the first graduate from that program in 2005.

Juliana Vidal: I discovered green chemistry in the very last year of my B.Sc. studies. I was reading an environmental chemistry book and studying for my exam when I saw a page with a picture of John Warner and Paul Anastas. I simply fell in love with the field and started to wonder why I had not learned about it before, which was the main motivation for my green chemistry journey and my work as a Program Manager at Beyond Benign. For those reasons, I was thrilled that my debut as part of the Green Chemistry journal community was in a work that discusses, promotes, and celebrates these collective journeys through the GCC program, and it is the result of a collaborative effort with some of my personal heroes, such as Amy Cannon, Natalie O’Neil, and John Warner.

Why did you choose to publish in Green Chemistry?

Besides its reputation for being one of the most influential and important journals in the field, Green Chemistry has recently released a ‘Green Chemistry 25^th Anniversary Collection’ Special Issue. As our team at Beyond Benign also looks to celebrate the work performed by our GCC participant institutions throughout the 10 years of the program, the Green Chemistry journal could not be a better place for this work to live and this double celebration to happen.

What do you think the Green Chemistry journal has done well in the past 25 years, and what do you think are the main challenges our community will face in the next 25 years? 

Throughout 25 years, the Green Chemistry journal has been home to some of the most important discoveries in the field, highlighting diverse approaches to green chemistry innovation and, most importantly, adapting itself to the new and incoming trends in green chemistry teaching and research. However, as new methods, processes, strategies, and even definitions emerge, our community will need to be as collaborative and as adaptable as possible to promote an in-depth inclusion of the field across sectors, organizations, and institutions within our society. However, acknowledging the past, recognizing mistakes, and planning a better future is something our community has excelled at throughout these 25 years, and that can still be our strength for the next 25 years to come.

Meet the authors

Dr Amy Cannon (she/her) is the Co-Founder and Executive Director of Beyond Benign, an organization that develops and disseminates green chemistry educational resources that empower educators, students and the community at large to practice sustainability through chemistry. She holds the world’s first Ph.D. in Green Chemistry from the University of Massachusetts Boston, and she worked as an Assistant Professor of Green Chemistry and Director of Outreach and Community Education at the Center for Green Chemistry at the University of Massachusetts Lowell. Amy was awarded the Kenneth G. Hancock Memorial Award in Green Chemistry in 2004 and the 2012 EPA New England Environmental Merit award for her leadership and work on green chemistry education, where she is focused on better-preparing students and scientists to enter the workforce trained with the skills to create sustainable materials and products. Through Beyond Benign, Amy leads many educational initiatives to bring together multiple stakeholders around this common goal.

Dr Juliana Vidal(she/her) is a Senior Program Manager at Beyond Benign, where she is dedicated to supporting the incorporation of green chemistry in higher education through the Green Chemistry Commitment (GCC) program. She completed her Ph.D. at Memorial University of Newfoundland, investigating new applications for a sustainable material obtained from wood waste. As a Postdoctoral Researcher at McGill University, she helped to develop greener methods for the implementation of a marine biorefinery. Juliana is the Co-Chair of the Global Conversation on Sustainability (GCS) project, a National Representative of the IUPAC’s Committee on Chemical Research Applied to World Needs (CHEMRAWN), a Coordination Member of the Chemicals & Waste Platform of the United Nations Environment Programme Major Group for Children and Youth, and was selected in 2020 a Chemical Abstracts Service (CAS) Future Leader.

Over the past 25 years, Green Chemistry has provided a unique forum for the publication of innovative research on the development of alternative sustainable technologies, efficient utilisation of resources and the concomitant minimisation of waste. We are delighted to bring together a very special issue containing articles by members of the green chemistry community as well as past and present Green Chemistry Board members, to mark and celebrate our first 25 years.

Among the contributions to this themed collection is a Paper on the chemical valorisation of biomass derived furanics and carboxylic acids over niobium-based catalysts (DOI: 10.1039/D4GC00207E).

Read our interview with Margarida M. Antunes, one of the corresponding authors.

Could you briefly explain the focus of your article to the non-specialist (in two or three sentences only)?

Our group wishes to contribute to a greener world by developing sustainable alternatives to fossil fuels using renewable and cheap sources of energy, which can be, for example, available biomass derived waste (e.g., forestry, agricultural or food waste). The main components of vegetable biomass include carbohydrates. Before using this available waste and convert it to green (biobased) products, it is important to investigate the chemical reactions involved. In this work, we investigated the conversion of furfural (which is an industrial platform chemical derived from carbohydrates) to drop-in-fuels, using relatively cheap and green catalysts.

How would you set this article in a wider context?

Niobium based oxides are known to have a lot of advantages, such as water-tolerance. This is very important since water is a co-product of the biomass conversion processes we intend to explore. Moreover, they possess Brønsted and Lewis acidity required for these conversion processes and have shown superior catalytic performance in relation to other metal oxides.

In collaboration with Dr Nicola Pinna and Dr Patrícia Russo (Humboldt University Berlin), niobium oxide nanoparticles embedded in a mesoporous silica matrix were synthesised by a relatively simple methodology. Our group investigated the catalytic properties. The prepared materials were stable in recycling runs in various reactions, such as for the aldol condensation of furfural with acetone, and for esterification reactions of alpha-angelica lactone, levulinic and valeric acid, which are all furfural derivatives. Moreover, they showed high acetone and ethanol consumption efficiency, which is important for an integrated biorefinery concept and sustainability.

What is the motivation behind this work?

Our group enjoys the fascinating field of Catalysis, which is crucial to the Chemical Industry. We explore selective and stable catalysts to efficiently promote target chemical reactions under moderate conditions, which may lead to more sustainable processes.

What aspects of this work are you most excited about at the moment and what do you find most challenging about it?

It was exciting to realize that indeed the niobium oxide nanoparticles embedded in a mesoporous silica (especially SiNb42 and SiNb75) could significantly increase the selectivity towards our main product, 4-(furan-2-yl)but-3-en-2-one (C8), in relation to the niobia nanomaterial Nb₂O₅, or in relation to a commercial micro Nb₂O₅ (which led to sluggish results) or yet in relation to a Nb₂O₅/TUD-1 composite using an equivalent atomic amount of Nb, prepared by embedding the Nb₂O₅ nanoparticles in a mesoporous TUD-1 type silica. Moreover, the Nb₂O₅ alone were partially deactivated in recycling runs, albeit when embedded in a mesoporous silica (using silica tetrachloride), their stability was enhanced. However, for Nb₂O₅/TUD-1 there was observed deactivation. The reasons for such behaviour are still not clear. The inherent properties of each material play an important role in their catalytic performance.

What is the next step? What work is planned?

Our next step is trying to use waste biomass sources instead of model substrates by using the acquired knowledge. This is of course a challenge, but we hope to count on the collaboration of scientists from the academia and industry, attempting to come closer to practical application.

Please describe your journey to becoming part of the Green Chemistry community

Since I integrated the associated laboratory CICECO, at the University of Aveiro, in 2008, I have been engaged in developing research work in the field of catalysis, with a mindset on sustainability and Green Chemistry. Developing research with this mindset is a reason for feeling proud.

Why did you choose to publish in Green Chemistry?

Green Chemistry is a prestigious journal, internationally recognised and read by many scientists, and valorises research that aims to reduce the environmental impact associated with the chemistry industry. In this sense, we thought that Green Chemistry was the best choice for our manuscript.

What do you think the Green Chemistry journal has done well in the past 25 years, and what do you think are the main challenges our community will face in the next 25 years?

During the last 25 years, the Green Chemistry journal has evolved according to the demands for sustainability. Several reviews and perspective papers have been discussed concerning the use of greener alternatives for fossil fuels. Environmental issues and sustainable solutions have been debated through life cycle assessment studies and techno economic studies. Some studies are promising and reliable experimentally, but the costs of the processes are still high. Sustainable processes for producing biofuels and biobased chemicals continues to demand much investigation. In the coming years, the way of use of fossil fuels and the supply chains should be rethought, which calls for the Green Chemistry community.

Meet the corresponding author

Margarida M. Antunes received a Licentiate degree in Industrial Chemistry from the University of Coimbra, Portugal, in 2004, where she studied the polymorphism of erythritol and threitol using differential scanning calorimetry and thermomicroscopy. In 2008, she earned a Master´s degree in Chemistry of Natural Products from the University of Aveiro (UA), where she synthesised and characterised pharmaceutical compounds. Margarida proceeded to doctoral studies at the UA, having concluded her PhD thesis in 2012, on the conversion of polysaccharides to furanic derivatives using either ionic liquids or heterogeneous acid catalysts. In the same year, she was awarded a post-doc grant from the FCT (Portuguese Foundation for Science and Technology) and in 2019 she became researcher at the UA, CICECO – Aveiro Institute of Materials. She investigates the catalytic conversion of several types of biomass derivatives to valuable bio-based products via heterogeneous catalytic routes. For example, D-fructose for food and non-food applications, fuel blends synthesised via condensation between biomass derived compounds (e.g. furfural) and glycerol, and gamma-valerolactone which is a promising fuel additive and intermediate for transportation fuels. She develops multifunctional heterogeneous catalysts to carry out multiple reactions (e.g. acid and reduction) in one-pot synthesis strategies. The heterogeneous catalysts include bimetallic, micro- and mesoporous materials prepared via different procedures, such as hydrothermal syntheses and top-down modifications (leading to hierarchical materials). Besides developing catalysts, Margarida is concerned about the energy efficiency of processes and has investigated different energy supply methods. One of her strong motivations is to study the sustainable repurposing of undesirable waste biomass sources to drop-in-fuels with reduced CO2 emissions compared to fossil fuels, via different catalytic strategies.

Over the past 25 years, Green Chemistry has provided a unique forum for the publication of innovative research on the development of alternative sustainable technologies, efficient utilisation of resources and the concomitant minimisation of waste. We are delighted to bring together a very special issue containing articles by members of the green chemistry community as well as past and present Green Chemistry Board members, to mark and celebrate our first 25 years.

Among the contributions to this themed collection is a Paper on the use of dipyridyldithiocarbonate (DPDTC) as an environmentally responsible reagent leading to esters and thioesters under green chemistry conditions (DOI: 10.1039/D3GC03093H)

Read our interview with Prof. Bruce H. Lipshutz, the corresponding author.

Could you briefly explain the focus of your article to the non-specialist?

This article focuses on developing technology for making fundamental bonds that follow Nature’s lead; that is, using the same types of intermediates used throughout evolution, and as witnessed today in the human body to arrive at these same important bond constructions. This green approach can be used by the pharmaceutical industry in making their drugs, as it provides an alternative that does not use organic solvents that deplete limited petroleum reserves, nor does it create waste. Thus, the major difference between existing methodologies and the one described in this paper is that prior art utilizes reagents that are waste-generating, and organic solvents that are flammable and toxic as the reaction medium, neither being recycled. This technology, however, relies on either no solvent or a recycled green solvent, providing the desired intermediates efficiently, while the by-product formed can be recycled.

How would you set this article in a wider context?

The use of traditional organic solvents, in particular, once spent, leads to organic waste which is to a large degree burned. These carbon-containing solvents, therefore, produce CO₂, a greenhouse gas, and hence, are contributing in a major way to climate change.

What is the motivation behind this work?

There is a need for all of modern organic chemistry to be redone, as it was developed over the past ca. 200 years based on organic solvents that predominantly derive from petroleum. The world needs methods, such as this one, which is representative of the possibilities for doing the same chemistry, but in an environmentally responsible manner.

What aspects of this work are you most excited about at the moment and what do you find most challenging about it?

Perhaps the most exciting aspect is the fact that the thioester intermediates initially formed are precursors to more types of products than the esters and other thioesters reported in this paper. In other words, they are also amenable to amide/peptide bond formation, which is the number one type of bond needed in the pharmaceutical industry. Thus, this technology was applied to the synthesis of nirmatrelvir, the key ingredient in Paxlovid. Once the amide/peptide is formed, the by-product can be easily recycled, so the amount of waste created is very low. This approach also applies to reduction of the same thioester intermediates, which represents a solution to the acid/ester issue that has for decades been done using highly dangerous and flammable hydride reagents, such as LAH and DIBAL. This alternative technology for the same reductions can now be accomplished in very inexpensive, water-containing 95% EtOH. The challenge was to find the “right” intermediate that allows each of these types of reactions to take place. As usual, the answer was to look to Nature, which has had over 4 billion years to develop solutions, as was found and applied to these fundamental problems.

What is the next step? What work is planned?

Applications; sequences; and direct comparisons. Applications:  there is no shortage of bioactive targets that are currently made using traditional, waste-generating activating reagents in waste-generating organic solvents and hence, need to be “re-made” from the green perspective. Sequences, meaning that chemistry involving these new technologies can be telescoped, thereby leading to multi-step processes run in a single vessel. And comparisons, showing the chemistry community, by known examples that going “green” always wins; always.

Please describe your journey to becoming part of the Green Chemistry community

It started by chance back in 2006, when our campus Health & Safety Director informed me, after their weekly pick up and recording of our organic waste, that my group was not only the largest waste-generating on campus or the largest waste generating group in the city of Santa Barbara; but that we were the largest polluter in all of Santa Barbara County. From that moment on, since the vast majority of waste is organic solvents, we focused on developing chemistry in Nature’s chosen reaction medium:  water.

Why did you choose to publish in Green Chemistry?

The readership knows that all papers must pass a rigorous evaluation of “greenness”; that if a paper is published in this journal, the work represents truly environmentally sound chemistry. Hence, as the world begins to shift towards sustainability, papers in Green Chemistry will take on a special meaning:  they represent environmentally friendly processes that are in line with the future, encouraging an awareness that must be eventually considered in all that we as chemists do.

What do you think the Green Chemistry journal has done well in the past 25 years, and what do you think are the main challenges our community will face in the next 25 years?

The most important action that this journal has taken in my view these past 25 years is its claim to the field:  it was an incredibly timely to claim its title:  Green Chemistry. This alone tells the reader all that one needs to know! Other journals getting into the area realize this, and have been/are trying desperately to compete; to find a way to get a similar meaning across. And while certain markets might allow for this competition, the reality is that Green Chemistry highlights the chemistry of the future.

The main challenges over the next 25 years are not in terms of the chemistry that appears in this journal, or any other journal catering to this area. New technologies will be developed and added to a growing toolbox. The problem that has been and is likely to remain is:  people. The science is there, and it will continue to get better. But people can get in the way: egos, money, changing regulations, job security, etc. This is the problem that Green Chemistry, and all journals dedicated to this essential field, must solve. This can be done, over time, with creative thinking, some financial backing, and a lot of effort. The success stories need to be told to a broad audience, and positioned in a way that makes each personal, with which the people reading/listening identify and have influence. We may never have a better chance to do this than today, with sustainability being a buzzword, and especially, climate change on most minds. But will we?

The Lipshutz research group

The Lipshutz research group continues to develop new technologies in green chemistry, with the specific goal being to get organic solvents out of organic reactioons, as organic solvents are, by far, responsible for most of the organic waste created by the chemical enterprise, and derive mainly from finite petroleum reserves. To accomplish this goal, the concept of “designer” surfactants has been introduced within the area of aqueous micellar catalysis. The nanoparticles that form in water from these amphiphiles act as nanoreactors, enabling key transition metal-catalyzed cross-couplings, and many other reactions, to be carried out in water under mild conditions.

The group has also focused its attention on developing new catalysts for key Pd- and several other transition metal-catalyzed reactions that enable C-C, C-N, and C-H bond formation typically at the parts per million level of the metal. Most recently, these newly developed technologies in chemo catalysis are being merged with enzymatic processes, done in tandem in 1-pot, and all in water.

Over the past 25 years, Green Chemistry has provided a unique forum for the publication of innovative research on the development of alternative sustainable technologies, efficient utilisation of resources and the concomitant minimisation of waste. We are delighted to bring together a very special issue containing articles by members of the green chemistry community as well as past and present Green Chemistry Board members, to mark and celebrate our first 25 years.

Among the contributions to this themed collection is a Critical review focusing on lignin, a biopolymer found in plants and trees (DOI: 10.1039/D4GC00745J). Chemical modifications of lignin are discussed and compared to each other in terms of sustainability aspects such as waste production and safety of the employed procedures. This literature review aims to increase awareness of the environmental implications that certain chemical procedures have, moreover wants to serve as a guide for researchers and industries towards more environmentally friendly practices.

Read our interview with the authors.

How would you set this article in a wider context?

There is the need to increase awareness regarding sustainability aspects and we, as scientists, are in a key position to drive sustainable innovations and environmental awareness further. Our article addresses not only the important renewability aspect of lignin, but also emphasizes practical insights as well as safer and less waste producing approaches. Beyond academia, the concepts and methods we discuss are relevant to industries looking for ways to reduce their environmental footprint, for example by utilizing lignin byproduct as a precious starting material for further applications.

What is the motivation behind this work?

The utilization of renewable resources has been a core principle of sustainable chemistry, since Anastas and Warner introduced the 12 Principles of Green Chemistry in 1998, which lay the foundation of sustainable development in chemistry. In this context, lignin remains an underutilized and often overlooked resource. Moreover, usually protocols focus only on the renewability aspect apported by lignin, often neglecting critical factors like toxicity, waste generation, and the reliance on additional petrochemical-based reactants. Our work aims to provide a systematic overview of the key protocols present in the literature based on the environmental factor (E-factor) for waste generation as well as toxicity aspects. We also categorized protocols based on the functional groups introduced to lignin, facilitating readers seeking targeted modifications.

What aspects of this work are you most excited about at the moment and what do you find most challenging about it?

The most exciting aspect of this work is the opportunity to explore and expand the potential of lignin as a sustainable resource. We are particularly enthusiastic about continuing our research into innovative and more sustainable modification techniques for this biopolymer, which could open new possibilities for its application. However, one of the main challenges we faced was obtaining sufficient data for accurate E-factor calculations, as some previous studies did not report critical information such as reaction yields for lignin modifications. We thus also hope our work encourages researchers to consistently report comprehensive data and to also apply metrics for sustainability comparison.

What is the next step? What work is planned?

This review summarizes established procedures for lignin functionalization, along with essential principles for assessing the sustainability and safety of these processes. This assessment was important for us in identifying critical issues related to lignin modification and in designing safer and more sustainable modifications protocols. We would further be very happy if our review would be of value to other research teams in helping them to develop more sustainable uses of lignin within their respective fields of expertise. Currently, we are exploring alternative methods for lignin modification focusing of the use of lignin as macromonomer for various cross-linked polymeric materials.

Please describe your journey to becoming part of the Green Chemistry community

Our group has a strong research focus on Green Chemistry for about 20 years, in particular on the utilization of renewable materials in the most sustainable way possible. It was clear from the beginning that Green Chemistry is the way to contribute to some of the most important challenges of our society. Within the last years, seeing climate change advance and the dependence on fossil resources remain high, our dedication further strengthened – we are happy to be part of this growing community and that Green Chemistry has developed to a mainstream topic over the years. With this growth and all its positive aspects of new and exciting ideas and developments, however, we have to be careful of greenwashing also in academic research.

Why did you choose to publish in Green Chemistry?

We chose to publish in Green Chemistry because it is a highly renowned journal in the chemistry field, that aligns closely with our dedication to sustainable chemistry. Our manuscript discusses and compares different protocols for lignin modification based on their adherence to the principles of Green Chemistry, making this journal the ideal platform to reach a readership dedicated to similar goals. We are excited to contribute to this field and believe our work complements the journal’s mission to promote scientific advancements in sustainable chemistry.

What do you think the Green Chemistry journal has done well in the past 25 years, and what do you think are the main challenges our community will face in the next 25 years?

The journal Green Chemistry has always set high standards in this field by publishing innovative research with sustainable chemistry practices, it was and is a highly important part for the development of the research community. As the demand for greener solutions increases, it will be essential for the Green Chemistry community to continue developing innovative methodologies, ensuring that new processes are implemented by industry in order to contribute to a sustainable development. This is not an easy task, as fossil resources and environmentally unbenign approaches are often established and economically favorable, for instance because the cost of environmental burdens or greenhouse gas emissions are externalized to society. CO₂ pricing might be the necessary gamechanger here, hopefully allowing many of the advances reported by the Green Chemistry community to be put into practice. A further and ongoing requirement will be societal awareness, improved for instance by education and outreach activities.

Meet the authors

	Celeste Libretti received her B.Sc. degree in Chemistry and Technologies for the Environment and Materials, and subsequently her M.Sc. degree in Industrial Chemistry, both from University of Bologna. She is currently a Ph.D. student in the working group of Prof. Dr Michael A. R. Meier, at the Karlsruhe Institute of Technology (KIT). Her research interests include cellulose and lignin structural modifications, as well as green chemistry.
	Luis Santos Correa is a Ph.D. student working in the group of Prof. Dr Michael A. R. Meier at the Karlsruhe Institute of Technology (KIT). He received his B.Sc. and M.Sc. degree in chemistry from KIT. His master thesis focused on the oxidative cleavage of sunflower oil. He is currently working on the synthesis of polycarboxylic acids from renewable resources and their potential application in polymer chemistry.
	Michael A. R. Meier studied chemistry in Regensburg (Germany) and received his Ph.D. from the Eindhoven University of Technology (The Netherlands) in 2006. After further stays in Emden and Potsdam, he was appointed as full professor at the Karlsruhe institute of Technology (KIT) in 2010. He has received several awards and is associate editor of ACS Sustainable Chemistry & Engineering. His research interests include the sustainable use and derivatization of renewable resources for polymer chemistry as well as the design of novel highly defined macromolecular architectures.

Over the past 25 years, Green Chemistry has provided a unique forum for the publication of innovative research on the development of alternative sustainable technologies, efficient utilisation of resources and the concomitant minimisation of waste. We are delighted to bring together a very special issue containing articles by members of the green chemistry community as well as past and present Green Chemistry Board members, to mark and celebrate our first 25 years.

Among the contributions to this themed collection is a Paper on a strategy to prepare hydrogel drug slow-release carriers for efficient mosquito larvae extermination using green biodegradable materials. (DOI: 10.1039/D3GC03625A).

This strategy provides a new way to expand the application of liquid marbles in green chemistry. The highly stable, highly loaded, and biodegradable slow-release hydrogel carrier was prepared based on liquid marble utilizing green and cheap materials for loading pyrethrin to kill mosquito larvae. The liquid marble endowed the drug carrier with superior floating stability at the water surface to kill mosquito larvae hanging below the water surface for survival and the electrostatic interaction between alginate and gelatin of this carrier can effectively reduce the degradation rate of pyrethrin in water exhibiting a long drug release time.

Read our interview with the authors.

What is the motivation behind this work?

People living in humid environments, especially next to lakes and swamps and in rainforests, are often attacked by mosquitoes. So we wanted to prepare a green biodegradable drug slow-release carrier loaded with green anti-mosquito drug (pyrethrin) to kill mosquitoes without damaging the local environment.

What aspects of this work are you most excited about at the moment and what do you find most challenging about it?

We find it most challenging to use the green route to impart good hydrophobicity and superior material stability to the drug carriers, and we are very excited about the long drug release time and superior floatation and storage stability of the drug carriers we have prepared.

What is the next step? What work is planned?

Our next steps will be to explore some research around liquid marbles in other directions of green chemistry. We will use the characteristics of liquid marbles to do some work in the fields of drug loading, adsorption and separation, and catalysis.

Please describe your journey to becoming part of the Green Chemistry community?

We wanted to reduce the number of mosquitoes in our living environment through green chemistry without damaging the environment, so we did work in this area. Green Chemistry, a top journal in the field of chemistry focusing on green chemistry and sustainability, was a perfect fit for our work, so we published our work in Green Chemistry.

What do you think the Green Chemistry journal has done well in the past 25 years, and what do you think are the main challenges our community will face in the next 25 years?

We consider that what the Green Chemistry journal has done best over the past 25 years is to provide a unique forum for the publication of innovative research in green chemistry as well as sustainable development. green chemistry is at the forefront of an evolving interdisciplinary field, so it is important to keep an eye out for innovative advances in green chemistry across disciplines.

Meet the authors   

	Qihui Zhang is a Professor of Pharmaceutical Chemistry at Chongqing University, who received his PhD degree from Shenyang Pharmaceutical University. As a senior visiting scholar, he finished his advanced study at the University of Chicago under the tutelage of Chair Professor Chun-Su Yuan. Professor Zhang is also the invited reviewer for more than ten top international journals. The main research interests of Professor Zhang include extraction, separation and structural modification of natural products based on molecular imprinting technology and nanotechnology.
	Liandi Zhou, born in 1978, Ph.D., graduated from China Medical University in 2008, Associate Professor, Director of Pathogenic Biology and Immunology Department, School of Basic Medical Sciences, Chongqing College of Traditional Chinese Medicine, Director of Chongqing Microbiology Society, and former expert of Chongqing Municipal Science and Technology Commission for reviewing medical projects. He has participated in one national-level project, two school-level projects of Chongqing Medical University, two planning textbooks of Science Press, and one school-level teaching reform project of Chongqing Medical University, and has published five papers on teaching reform. Her main research interests include the regulation of immune-related diseases by active ingredients of traditional Chinese medicine and their mechanisms, and she has published more than 20 SCI papers as a corresponding author.
	Dr. Saimeng Jin obtained his PhD degree in chemistry from the University of York (United Kingdom, with Prof. James Clark) in 2017 and his BSc degree from the Sichuan University (China, with Prof. Bi Shi) in 2010. He currently works as a Associate Professor at the School of Chemistry and Chemical Engineering, Chongqing University. He hosts the National Natural Science Foundation of China (No. 22208036). His research interests include dimethyl carbonate chemistry, conversion of biomass.
	James Clark is Professor of Chemistry at the University of York, and is Founding Director of the Green Chemistry Centre of Excellence and the Bio-renewables Development Centre. He is also Chair Professor at Fudan University in China and holds honorary doctorates at the Universities of Ghent, Leuphana and Umea. He is a Visiting Professor at Sichuan University and was the International Visitor at the University of cape Town. He has won prizes and awards from many organisations including the 2018 Royal Society of Chemistry Green Chemistry Prize and the 2021 European Sustainable Chemistry award. His research involves the application of green chemical technologies to waste or low value feedstocks notably biomass so as to create new green and sustainable supply chains for chemical and material products. Some of his discoveries in research include a new bio-based solvent Cyrene® to replace toxic amides (produced by Circa Group Ltd including in a new €50M manufacturing plant in France), unique bio-based carbonaceous materials (commercialised through his award-winning spin-out company Starbons® Ltd with applications in areas including medical devices) and new routes to waste plastics recycling (through his new spin-out company Addible.Ltd). James has also been very actively involved in green chemistry publishing, education and networking: he was founding editor of the world-leading Green Chemistry journal, heads the advisory board for the RSC Green Chemistry book series and he was founding director of the worlds’ longest running green chemistry MSc program as well as the Green Chemistry network and the Global Green Chemistry Centres network. (“G2C2”).