Picloram physical

Van der Waals forces were considered to be involved in the physical adsorption of Carbaryl, Parathion, Alachlor, Picloram, and 2,4-D by SPHs [17,25,152, 160-162]. 

Phosphoric Acid Phosphorus Photoallergens Photochemical Oxidants Phthalate Ester Plasticizers Physical Hazards Picloram Picric Acid Piperazine Piperonyl Butoxide "Plants, Poisonous" Platinum (Pt) Plutonium (Pu) Poinsettia Poisoning Emergencies in Humans Pokeweed Pollutant Release and Transfer Registries (PRTRs) Pollution Prevention Act "Pollution, Air" "Pollution, Air Indoor" "Pollution, Soil" "Pollution, Water" Polybrominated Biphenyls (PBBs) Polybrominated Diphenyl Ethers (PBDEs) Polychlorinated Biphenyls (PCBs)... 

Davidson, J.M., and R.K, Chang. 1972. Transport of picloram in relation to soil physical conditions and pore water velocity. Soii Sci. Soc. Am. Proc. 36 257-261. 

The physical properties of pyridine-containing acids make them particularly attractive starting points for combinatorial libraries for herbicide screens. Pyridines are relatively polar (log P = 0.60 for pyridine vs. 2.13 for benzene) (4) and the sinq>le unsubstituted acids are weakly acidic (nicotinic acid pKa 4.8). (5) Perhaps for these reasons, pyridine-containing acids have found considerable utility as herbicides. Representative examples of commercially successful, phloem mobile, pyridine acids (or dieir derivatives) include picloram, clopyralid, and triclopyr (synthetic auxins) imazethapyr and nicosulfuron (ALS inhibitors) clodinafop and haloxyfop (ACCase inhibitors). Each has a direct counterpart in the conesponding benzene series but, in these instances, the pyridine analog is invariably the superior herbicide. 

A wide variety of aromatic acids have been used as herbicides. Some of these, such as amiben, dicamba, and picloram, mimic auxin in their mode of action, similarly to 2,4-D however, they possess chemical, biochemical, and physical characteristics that make them more suitable for particular applications than 2,4-D is. Expiration of patent protection for many of the aromatic acid herbicides has led to their manufacture by a number of companies. 

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