From Laboratory Sample to Scale-Up: Interview with Klára Novotná from Zenthin Chemicals R&D
Developing a successful laboratory sample is a demanding and complex step in itself, but in chemical development, it is only the beginning. Scaling a formulation up from a glass flask to a multi-tonne reactor, accounting for the physical effects that emerge during scale-up, meeting regulatory requirements and delivering consistently reproducible quality to procurement teams requires far more than textbook chemistry. In this interview, Klára Novotná from Zenthin Chemicals Research & Development (R&D) takes us behind the scenes of industrial chemistry and explains why successful R&D depends on precise data, robust processes and the ability to bridge the gap between laboratory development and full-scale production.
People often imagine product development as taking place in a quiet laboratory filled with bubbling test tubes. In reality, however, the work doesn’t end once you have produced a functional sample. Beyond the “textbook chemistry” itself, what else has to be addressed before a product can be scaled up to industrial production, remain stable over time, meet regulatory and customer requirements and still make economic sense?
Preparing a functional sample in the laboratory is “only” the first step. Even finding a suitable process is rarely a matter of a single experiment. We naturally draw on specialist literature and published research, but a specific technological process for the required product is often simply not available. Our customers are also no longer looking only for “textbook” surfactants. Increasingly, we work with atypical raw materials or requirements for a specific composition and precisely defined product properties.
Another crucial stage is scaling the laboratory process up to full production. A process that works perfectly well at a scale of a few millilitres or litres may behave very differently when several tonnes are being produced. We therefore have to consider factors such as raw-material dosing, mixing, heat transfer, reaction behaviour, by-product formation, subsequent purification and the overall robustness of the process. At the same time, we need to identify process conditions that are not only technically feasible, but also safe and economically viable.
Product stability is another major part of development. We monitor how the product behaves at different temperatures and during storage, checking whether characteristics such as appearance, viscosity, homogeneity and other key parameters change over time. We also have to allow for slight variations in the properties of incoming raw materials from one delivery to another, so the process must be sufficiently robust to accommodate these differences.
Customers sometimes make mistakes when defining their requirements. In what specific sense? Ideally, what would you need to know at the very first meeting to avoid dead ends and save the customer weeks of unnecessary testing?
When the requirement concerns a new product or blend, the first thing we need to understand is its intended application, the properties it should have, what it should look like and which parameters it needs to meet. The more precisely we understand the intended application and required properties, the better we can steer development in the right direction from the outset and avoid pursuing variants that would ultimately be unsuitable for the customer.
If a customer is looking for an alternative to a product already available on the market, having access to a physical sample and its technical specification is extremely helpful. This allows us to compare not only the declared parameters, but also how the product actually behaves, giving us a much clearer indication of the direction the development work should take.
When a procurement specialist or process engineer comes to you with a requirement for a new raw material or a change to an existing one, what is the very first thing you do?
When changing a purchased raw material, the first step is to analyse the new material and compare its technical parameters with those of the material currently in use. If the new raw material is very similar in terms of composition and purity, we use it to prepare a trial product and verify whether its appearance, behaviour and analytical parameters are comparable with those of the product made using the original material. In practice, however, this also depends on which raw materials are currently available and what the logistics team is able to source.
An Zenthin Chemicals surfactant may have excellent parameters on its own, but once a customer adds it to a finished formulation, a particular fragrance system or the presence of salts may lead to unexpected interactions. When something like this happens, how difficult is it to return to the surfactant itself and fine-tune it for that specific customer formulation?
Surfactants are amphiphilic molecules, meaning that they contain both a water-attracting part (hydrophilic) and a part with a greater affinity for non-polar substances (hydrophobic), such as oils. Because of this structure, they can organise themselves in different ways in solution, and their behaviour in complex multi-component systems is therefore not always easy to predict. Depending on the composition of the formulation, both the way in which the surfactant molecules aggregate and the phase behaviour of the overall system may change.
These changes may manifest themselves as changes in viscosity, clouding, precipitation of certain components, phase separation or gelation. When dealing with this type of problem, it is therefore essential to know the composition of the customer’s formulation as precisely as possible. Only on the basis of this information can we assess in a targeted way whether the best solution is to modify the surfactant itself, adjust its concentration or change the ratio of the individual components in the formulation.
Large chemical groups tend to work with fixed product catalogues and very high minimum order quantities. Zenthin Chemicals, by contrast, is built around a high degree of flexibility and customer-specific modification. How challenging is it for R&D to accommodate these individual requirements, from adjusting the hydrophilicity of copolymers to fine-tuning foaming performance?
It varies considerably from case to case. Sometimes a relatively small change to the formulation is enough to achieve the required properties within a matter of hours or days, for example when the sales team needs to prepare a blend from surfactants that we already manufacture. In such cases, we usually optimise the process and the order in which the individual raw materials or products are mixed. Where necessary, we also look for a suitable emulsifier, dispersant, preservative or other auxiliary ingredient so that the product meets the required expectations. At other times, development is considerably more complex because changing one parameter can affect several other properties at the same time. Development is therefore often iterative: we prepare different variants, test them and look for the optimum balance between product properties, manufacturing feasibility and economics.
The most demanding projects are those where it takes several months to find a suitable formulation. It is all the more disappointing when, after a long development process, we finally succeed in fine-tuning the product to the required specification, only to find that the customer or the market is no longer interested in it. That, too, is part of the reality of development. Sometimes the technical solution is found only when the original commercial opportunity is no longer current. The experience and data gained, however, can often be used in subsequent development work.
In the laboratory, you prepare a perfect one-litre sample. But what happens when the process is transferred to a multi-tonne reactor? Where are the greatest technological risks during scale-up, and why can heat transfer, mixing or the dosing method be just as important as the chemistry itself?
One major advantage of laboratory-scale preparation is that you can see directly into the glass sulfonation flask. You can immediately observe, for example, a change in colour, foam formation or phase separation. With a multi-tonne reactor, you do not have this option. Instead, you have to rely on process parameters such as temperature, pressure or agitator power consumption. This is why scaling a product up from the laboratory to production is always carried out in close cooperation with a process engineer, and the process is only handed over once production is stable and reproducible.
For procurement, the key question in the end is not whether the first batch was successful, but whether the fiftieth will be exactly the same. It is precisely the link between the laboratory and production through the process engineer, together with repeated verification at production scale, that makes this level of reproducibility possible.
Today, development is no longer just about chemistry; it also has to contend with increasingly stringent regulatory requirements. How much do these requirements affect the development process itself, and why should procurement teams pay close attention not only to the price per kilogram, but also to raw-material quality and documentation?
Increasingly stringent legislation has a significant impact on development work. For us, this means having to develop and refine analytical methods so that we can reliably determine even very low concentrations of the impurities being monitored. Naturally, this is also reflected in the price. A product subject to stricter purity requirements requires more complex processing, higher-quality raw materials and more costly quality control. This is why purchasing decisions should not be based solely on price per kilogram, but also on the consistency of the raw material and the reliability of the supplier’s documentation.
One major issue today is reducing undesirable substances, such as 1,4-dioxane in ethoxylated surfactants. How do you deal with this pressure in practice?
In ethoxylated surfactants, the 1,4-dioxane content is reduced by vacuum stripping, which at Zenthin Chemicals is carried out directly in production rather than in the R&D laboratory. Our aim is not to “purify the product at any cost”, but to bring the 1,4-dioxane content safely below the required limit while maintaining product performance. We then check the content in the laboratory using gas chromatography-mass spectrometry.
From your perspective as a chemist, where does a genuine effort to make production more environmentally sustainable end and marketing greenwashing begin?
From a chemist’s point of view, I would regard sustainability measures as genuinely meaningful above all when they have a measurable impact: using more suitable raw materials, reducing the energy intensity of production, reducing waste or lowering the content of undesirable substances. I would start to describe something as greenwashing when one “green” parameter is emphasised while the overall production process, energy consumption and transport are no longer taken into account. For us in R&D, working with concrete data is more important than relying on a marketing label.
Working in industrial R&D clearly requires a very broad range of skills. If you were advising young chemists, what would you say matters most for success in the laboratory?
Everyone has to start somewhere, and the most important things are to be interested, willing to learn and unafraid to ask questions. We have two colleagues here who started at Zenthin Chemicals as interns. One now works with us full-time, while the other is currently working with us alongside her studies under a part-time work agreement.
Knowledge gained at university is an important foundation, but it is not enough on its own. In practice, you need to combine theoretical knowledge with laboratory experience and the practical possibilities of production, while working closely with colleagues from other departments. It’s precisely the combination of technical expertise, common sense, patience and a willingness to look for solutions that is key to success.
And finally, on a lighter note: do you suffer from occupational habits? Do you ever catch yourself studying shampoo labels in the drugstore?
It is true that since I started working at Zenthin Chemicals, I pay much more attention to the ingredient lists of shampoos, hair-care products and cleaning products. You automatically start noticing which types of surfactants the manufacturer has used and why. But you still can’t determine the exact formulation from the label. Cosmetic products at least list the individual ingredients by name, although without their concentrations, while cleaning products may list some ingredients only by category, for example “non-ionic surfactants”. So yes, I definitely have an occupational habit, but unfortunately a label is still not enough to reconstruct the complete formulation. 😊
