Potential agrochemicals

Miles, D.H. et al.. Potential agrochemicals from leaves of Wedelia biflora, Phytochemistry, 32, 1427, 1993. 

Quite a number of myxobacterial natural products have been produced by cultivation of the respective species in large-scale fermenters, which is often achieved on technical media. This includes processes for generating potential agrochemicals and pharmaceuticals such as the cUnically used anticancer compound epothilone (see Section 12.8.3). 

NAIR Natural Products as Sources of Potential Agrochemicals... 

Biodegradation is a most important parameter for any potential agrochemical. It is essential that residues of chemicals which are applied to soil, or reach it from other sources, are decomposed at a rate fast enough to prevent their build up in soil. It has been observed that the addition to soil of a readily metabolizable substrate, such as a carbohydrate, may enable an"organism to degrade recalcitrant compounds. Examples of such... 

Phospholipid molecules form bilayer films or membranes about 5 nm in thickness as illustrated in Fig. XV-10. Vesicles or liposomes are closed bilayer shells in the 100-1000-nm size range formed on sonication of bilayer forming amphiphiles. Vesicles find use as controlled release and delivery vehicles in cosmetic lotions, agrochemicals, and, potentially, drugs. The advances in cryoelec-tron microscopy (see Section VIII-2A) in recent years have aided their characterization [70-72]. Additional light and x-ray scattering measurements reveal bilayer thickness and phase transitions [70, 71]. Differential thermal analysis... 

The current or potential iadustrial appHcations of microemulsions iaclude metal working, catalysis, advanced ceramics processiag, production of nanostmctured materials (see Nanotechnology), dyeiag, agrochemicals, cosmetics, foods, pharmaceuticals, and biotechnology (9,12—18). Environmental and human-safety aspects of surfactants have begun to receive considerable attention (19—21). 

As for waste from the production of chemicals, the array of structures represented by agrochemicals is truly enormous. Only some illustrative examples are provided, and it is important to emphasize that not only the original compound, but also potential metabolites should be considered. The pathways for biodegradation of many of the structures have been presented in Chapter 9 and reference should be made to these for details. There is increased interest in the degradation of agrochemicals after application, and abiotic reactions including photochemical degradation that are important on the soil surface are discussed in Chapter E... 

Homogeneous catalysis has an important role to play in enantioselective reactions. To improve product safety, the pharmaceutical industry is producing an increasing number of products in enantiomerically pure form. Other important (future) markets include agrochemicals, polymers and fine chemicals. Although the number of practised processes is quite small the potential is high. 

Application rate is generally dictated by the labeled, or anticipated, application rate relevant to the particular use pattern being investigated. To improve analytical detection or to compensate for potentially low zero-time application recoveries, application rates are sometimes increased to 110% of the labeled application rate. An application rate greater than this level would be subject to regulatory scmtiny and may affect the dissipation rates of certain agrochemicals owing to potential short-term effects on sensitive soil microflora. 

Spray nozzle type plays an important role in the success of agrochemical application. For broadcast applications to soil, flat fan nozzles should be used. Newer spray tips such as the DG TeeJet, XR TeeJet, Turbo TeeJet and similar nozzles supplied by Lechler and Hardy have provided acceptable results in a number of studies. For a given nozzle type, the lower the application pressure, the larger is the spray droplet size and the less potential for spray drift. Similarly, the closer the boom is positioned to the soil surface, the less is the potential for spray drift." Most applications are made with spray tips having 80° or 110° spray angles and boom heights of about 50 cm above the soil surface. 

Cyanohydrins have considerable synthetic potential as chiral building blocks, especially in a wide range of pharmaceutical and agrochemical applications. The remarkable properties of the HNLs can be exploited in catalyzing stereoselective synthesis of cyanohydrins. Especially... 

KoC is an important parameter which describes the potential for movement or mobility of pesticides in soil, sediment and groundwater. Because of the structural complexity of these agrochemical molecules, the above simple relationship which considers only the chemical s hydrophobicity may fail for polar and ionic compounds. The effects of pH, soil properties, mineral surfaces and other factors influencing sorption become important. Other quantities, KD (sorption partition coefficient to the whole soil on a dry weight basis) and KqM (organic matter-water partition coefficient) are also commonly used to describe the extent of sorption. K0M is often estimated as 0.56 KoC, implying that organic matter is 56% carbon. 

The ability to efficiently synthesize enantiomerically enriched materials is of key importance to the pharmaceutical, flavor and fragrance, animal health, agrochemicals, and functional materials industries [1]. An enantiomeric catalytic approach potentially offers a cost-effective and environmentally responsible solution, and the assessment of chiral technologies applied to date shows enantioselective hydrogenation to be one of the most industrially applicable [2]. This is not least due to the ability to systematically modify chiral ligands, within an appropriate catalyst system, to obtain the desired reactivity and selectivity. With respect to this, phosphorus(III)-based ligands have proven to be the most effective. 

---