Corbion: Going Green - Exploring the Potential of Biobased Solvents

The agrochemicals industry is facing an imminent challenge. With the population rising at a rapid rate, the demand for global food supplies, grains in particular, is greater than ever. Farmers are therefore facing mounting pressure to improve crop yield and quality, amidst an increasingly stringent regulatory environment. As pesticide formulators seek innovative solutions that deliver optimum efficacy, safety and legislative compliance, bio-based solvents are showing promise in a challenging market that is constantly evolving.

The changing landscape

After some years with market decline, the agrochemicals market rebounded in 2017 and the outlook for the coming years is positive – 3% growth is expected for 2018.  The ongoing need for innovative agrochemical products results from various challenges farmers are facing to ensure supply to the fast expanding population. Key barriers for farmers to provide high-quality yields are increasing crop losses through pest attacks and lack of available arable land as result of urbanization. As such, there is an ongoing need for agrochemical products that manage these challenges, while providing high-quality yields to meet the rising demand.

While this provides an ongoing market need for new agrochemical products, growing concerns about potentially negative effects of agrochemicals on humans and the environment has led to more stringent regulations across the world. In fact, several recently published reports claim the widespread use of traditional synthetic pesticides, insecticides, fungicides and herbicides at industrial scales is not safe.  With limits being placed on pesticide use, formulators are therefore seeking agrochemical formulations with reduced toxicological classifications.

Ongoing regulatory scrutiny

In recent decades, the number of new molecules brought to the market has decreased. This is partially due to increasingly stringent regulations, resulting in more time to bring new agrochemical active ingredients (AIs) to the market; it now takes 11 years, on an average.  With more and more governments around the world introducing new controls and legislations, the pressure on manufacturers to reformulate existing synthetic agrochemicals is not slowing down. The fact that the EU  has recently banned neonicotinoids – the world’s most widely used group of insecticides – gives an indication of the direction the market is taking. Meanwhile, the Chinese government is now demanding formulations that are safer, with minimal impact on the environment.

Safety is also high on the agenda for formulators, and remains a significant factor in developing new formulations. This is increasingly apparent in the EU, which continues to lead the way in setting regulatory standards – ahead of other countries around the world. For example, the introduction of the EU Directive 1107/2009 (effective from June 2011) and REACH means there is a greater requirement for innovative formulations that are compliant, while maintaining a critical competitive edge.
The current benchmark

Agrochemical formulations commonly comprise solvents derived from petrochemical sources. These include aliphatic paraffinic oils, aromatic solvents (hydrocarbons), alcohols and ketones. Examples include ethylbenzene, N-Methyl-2-pyrrolidone (NMP), cyclohexanone, and 1,2-Dichlorobenzene. Although effective, particularly in terms of solvency, the inclusion of these chemicals can have significant drawbacks. For example, some of them contribute to volatile organic compound (VOC) emissions, which can pose a threat to human health and harm the environment. Furthermore, some of them are also classified as hazardous air pollutant (HAP) substances (i.e. ethylbenzene). As such, they are considered toxic to users and farmers, as well as phytotoxic to crops in some cases. In addition, as these solvents are generally derived from an unsustainable source, their use is an additional cause of concern for the environment.

Bio-based solvents

Thanks to developments in recent years, green or bio-based solvents could offer significant value to crop protection formulations, as well as important improvements in operator safety. Although the definition varies across the industry, green or bio-based solvents generally refer to the fact that they are produced from renewable resources, are biodegradable, non-corrosive and non-toxic. Interest in bio-based solvents is expanding exponentially, both for biocontrol solutions and general pesticides. Besides their use in agrochemicals, bio-based solvents are increasingly applied in other markets such as electronics processing, textile dyeing, cleaning formulations, coating production and various consumer products.  

For formulators it is essential to look for bio-based solvents that can perform at the same level, if not better than petrochemical alternatives, with comparable solvency properties and efficacy of AIs in formulation. It is also crucial that these benefits do not bring a substantial cost impact, particularly given the rising costs of crop protection worldwide.

Lactate ester technology is a relatively new class of bio-based solvents that is gaining traction with formulators. It has been observed that lactate esters, which are derived from natural lactic acid via the processing of agricultural crops, can enhance herbicide efficacy, performing similarly to adjuvants. As such, lactate esters present a viable option for bridging the gap in the market, giving formulators the peace of mind to develop trusted formulations, that not only protect end users, but their businesses too.

Meeting the challenge

In addition to achieving optimum safety, manufacturers seek more diverse properties for their formulations. There is often a requirement to incorporate different formulations of fungicides, insecticides and herbicides into the same tank mix preparation, to save valuable time and costs when it comes to spraying the formulation onto the crops. The development of several AIs in the same formulation prevents physical-chemical incompatibilities, which can lead to reduced spray efficiency, as a result of clogging in the nozzles, for example. In the face of these increasingly complex formulations, complete solvency of AIs is becoming more important than ever.

An important consideration for formulators when choosing solvents includes solubility as a function of temperature. Lactate esters present little variation of solubility for tested pesticides. An additional consideration is the wettability (spreadability) on leaves once the formulation is sprayed. Again, lactate esters display excellent wettability characteristics across a wide range of water concentrations.

Innovative formulations

The current legislative climate, together with pressures from a rising population, are causing manufacturers to reconsider their agrochemical formulations. However, any alternatives to traditional solvents need to exhibit high performance, enhanced safety and strong sustainability credentials, highlighting an ongoing challenge.

Bio-based solvents, such as Corbion’s PURASOLV® lactate esters, provide a practical alternative for formulators of agricultural insecticides, fungicides and herbicides. Using readily available natural ingredients, Corbion’s toolbox of bio-based solvents offers cost-effective, safe options. The solvents exhibit good phyto-toxicological profiles and excellent solvency, making sure formulators can continue to innovate in a constantly evolving market, while also working towards ensuring a more sustainable future.


1. Phillips McDougal, 2018.
2. A. Milner and I. Boyd, ‘Toward pesticide vigilance,’ Science, vol. 357, no. 6357, 2017, 1232-1234.
3. Phillips McDougall, ‘The cost of new agrochemical product discovery, development and registration in 1995, 2000, 2005-8 and 2010-2014’, [report], 2016.
4. ACS, ‘How Industrial Applications in Green Chemistry Are Changing Our World,’ 2015.

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