Solvents are typically used in oil containing formulations such EC, EW, SE, but sometimes even in water soluble compositions like SL. In general, there is an increasing reluctance to accept solvents which are classified as CMR (carcinogenic, mutagenic, or reprotoxic). With logP as a criterion, solvents can be categorized in three groups i.e. hydrophobic (logP > 3), water soluble (log < 0), and partially water soluble ones in between (logP=0-3). Within the group of hydrophobic solvents for example, toluene is classified as CMR, xylene a reproductive hazard, and solvent naphtha as carcinogenic. As for water soluble solvents, the formamide, acetamide, NMP are all teratogenic. In addition, some traditionally used solvents like xylene and toluene have the problem of low flash point and high volatility. Consequently, there is a need for safer alternatives. Any new solvent development must combine suitable physico-chemical properties with acceptable tox and ecotox profiles to satisfy regulations outlined by REACH and the EPA (40 CFR part 180). When alternatives become available, their performance often does not meet industry benchmarks such as NMP, which is a versatile product with outstanding solvency. However, there can be an antagonistic effect on plants to the point where phytotoxicity occurs after application on certain crops. Ideally, a good new solvent enhances the biological performance of actives. This paper will give an overview about recent solvent developments and suitable methods. While the portfolio of standard solvents for formulation chemists has diminished, safer alternatives exhibiting an improved performance profile have been developed. With high regulatory hurdles in place, the rate of solvent innovation is decreasing.

Solvents: Latest innovations in agrochemical formulations and applications

248th National Meeting (2014)

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