Mechanochemistry might be an entirely new topic for many of you. But don’t worry, we’ve prepared a handy mechanochemical glossary to help you get to grips with some of the most used terms and concepts in this fascinating branch of chemistry.
Today’s article is the third in a series of four blogposts. We are launching our personal dictionary, with terms arranged in alphabetical order, of course. This edition covers terms from M to R. If you missed our first and second instalments, you can read them here and here. And now, let’s get started!
Mechanochemical methods
We could say a method is how we do something, a particular way of doing it. So, when we talk about mechanochemical methods, we are talking about the way in which mechanochemistry is performed. This includes the use of devices such as ball mills, bead mills and extruders, among others. But this term also refers to the fact of avoiding solvents and, instead, performing reaction by mashing, crushing and milling the components.
Mechanochemical reaction
Quoting the IUPAC “Gold book”, it is a “chemical reaction that is induced by the direct absorption of mechanical energy”. This energy can take many forms. It may involve milling the components, mashing them, or even mixing the chemicals by exposing them to sound waves. The latter is known as resonant acoustic mixing, and it is also the last term in our glossary.
Mechanochemistry
The term “mechanochemistry” was first coined by the chemist and Nobel laureate Wilhelm Ostwald as “the coupling of mechanical energy and chemical energy”. Today, we can define mechanochemistry as a method of chemical synthesis induced by external mechanical energy, using techniques such as ball milling, twin-screw extrusion or spray drying. An important aspect is that this approach avoids the use of solvents, making it a more sustainable option than traditional chemistry. Another advantage is that it enables reactions that are impossible by conventional methods, due to the levels of energy required and issues of solubility.
Milling dynamics
This term refers to what happens within ball or bead mills. In other words, it describes the complex interactions of forces, motion, and energy transfer during grinding or milling, which influences how solid materials are mixed, crushed, and react. These dynamics are governed by several parameters and factors, including the type of mill, the size and material employed, as well as factors such as impact frequency, impact velocity, and impact energy. Understanding milling dynamics is essential to our work, as what takes place when molecules collide cannot remain a mystery.
Molecule
A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds. It represents the smallest identifiable unit of a pure substance that retains both its composition and chemical properties. Molecules also form the foundation of pharmaceutical products, which is why they are so important to us!
Multicomponent crystalline system
A multicomponent crystalline system is a solid composed of two or more distinct chemical substances, or components, which can enhance the efficacy, solubility, and stability of the overall product. The complexity of such systems increases with the number of components involved. In the solid state, they typically exist as salts, solvates, or cocrystals. More specifically, multicomponent pharmaceutical materials are solids in which at least one component is an active pharmaceutical ingredient (API).
Pharmaceutical industry
The pharmaceutical industry is dedicated to the research, design, development, manufacture, and distribution of drugs and medicines. It is an extensive sector that involves many different stakeholders, including manufacturers, biotechnology companies, and distribution networks. It is also an industry that generates vast revenues and holds significant influence. Pharmaceutical companies may be private or public.
Pharmaceutical supply chain
From the moment a drug is conceived to the point it reaches us and heals us, it goes through many hoops. We are talking about the pharmaceutical supply chain. It involves sourcing raw materials, manufacturing, distribution, and the delivery of medicines. This chain is quite a complex one, as many actors are involved, including suppliers, pharmaceutical companies, healthcare providers, and patients. As a result, it requires careful coordination and strict regulatory guidelines that ensure medicines are safe and effective.
Physical or mechanical force
This term refers to a physical interaction that can cause a change in either the motion or the shape of an object. It occurs when two bodies come into contact or act upon each other at a distance, producing effects such as pushing, pulling, or compressing. As a result, it may lead to acceleration, deformation, or stress within materials. In mechanics, it is treated as a vector quantity, defined by its magnitude, direction, and point of application. And thanks to these physical interactions, we can drive our reactions without using solvents!
Purification
Purification is the process of isolating and separating a chemical substance of interest from contaminating substances, thereby removing impurities and improving the quality of the compound. In chemical reactions, products are not always obtained in pure form, as side products or residual reagents may remain. Purification ensures that these unwanted substances are eliminated, yielding the desired compound. This step is essential, as impurities can affect the reactivity, properties, and feasibility of scaling up of chemical processes.
Resonant acoustic mixing (RAM)
At IMPACTIVE, we use many different mechanochemical techniques, such as ball or bead milling, where balls or beads mash the compounds to induce new transformations. RAM, however, is a bit special. This technique usually needs only the help of low-frequency sound waves to enable chemical transformations by intensively mixing the materials under very high acceleration. This means there are no impacts coming from any external milling media. Instead, the reaction-driving forces come from the shearing of particles alone.