Esters, herbicidal properties

Chem. Descrip. Sulfonate and POE ether blend Ionic Nature Anionic/nonionic Uses Specialty emulsifier for phenoxy-ester herbicides Properties Liq. oil-sol. 

Two groups of sucrose derivatives of herbicidal acids have been reported. The herbicidal properties of the sucrose esters of (2,4-dichlorophenoxy)-acetic acid and other analogs differed somewhat from the salts of the free herbicide acids. This could be accounted for as being due to differences in solubility and penetration, since it is unlikely, by analogy to the fatty acid esters, that the sucrose esters would remain intact in the plant. 0 The second set of sucrose esters were water-soluble sirups, having surfactant properties, prepared from reaction products of hydroxyethyl ethers of sucrose or diglycidyl ethers of poly(oxyetbylene glycol) with (2,4,5-tri-chlorophenoxy) acetic acid or other herbicidal acids. 1... 

Pebulate (8), S-propyl butylethylthiocarbamate, is a thiocarbamic acid ester containing an asymmetric amine. Its herbicidal properties have been described by Burt (1959). 

Esters. The ester forms of acid herbicides are always more volatile and less water soluble than the acid or salt forms (Tables IV and XI). The ester forms are eventually hydrolyzed to acid anions in aqueous and soil systems, but in the ester forms they are nonionic and relatively volatile. Properties of several ester herbicides are given in Table XL... 

Table I. Herbicide Property Ranges for Commercial Products and the Ring-Fused 2-Pyridinone Ester Library...

Uses Surfactant for use with postemergent herbicides Properties Amber Ilq. ester odor emulsifies in water sp. gr. 0.90 b.p. 275 F flash pt. >300 F pH 6-7... 

Chloroacetaldehyde, production from acetaldehyde, 1 105 Chloroacetamide, l 142 herbicides, 13 303 Chloroacetate esters, 1 142 physical properties of, 1 142t Chloroacetic acid, 1 136-139 end use of chlorine, 6 135t physical properties of, l 137t producers, l 139t... 

It has long been known that detergents increase the effectiveness of auxin herbicides. This may now be interpreted as perhaps not due entirely to the wetting properties of the detergents and it would be of interest to compare fatty acid ester detergents with those not containing fatty acid groups in herbicide trials. 

Phosphate esters are widely used in metalworking and lubricants. A C12 h with 6 mol of ethylene oxide (diester) can be used as an emulsifier but also as an extreme pressure additive - it can reduce wear where there is high pressure metal to metal contact. PEs can also show corrosion inhibiting properties, as with petroleum sulphonates and the emulsifying power of PEs with low foam is used in agrochemical formulations. PEs can act as dispersants or hydrotropes in plant protection formulations, allowing the development of easy-to-handle and dilute formulations of both poorly miscible and insoluble herbicides. 

The enzymatic assay of herbicides is methodologically based on their common pharmacological property to inhibit the activity of a group of enzymes involved in the hydrolysis of choline esters. When an enzyme activity is measured under controlled conditions, the degree of inhibition induced by the sample is a measure of the quantity of the target herbicide. The enzymatic analytical process involves competitive interactions between the enzyme and the substrate, on the one hand, and between the enzyme and the target analyte, on the other. 

Dichlorophenoxyacetic acid (2,4-D) is a selective herbicide used for weed control, water hyacinth control, and various other uses. Several companies manufacture 2,4-D. 2,4,5-T, salts, and esters are used widely to control woody plants on industrial sites and range land. Amine formulations are used extensively for weed control on rice. The action and properties of these compounds are similar to those of 4,5-T preparations. 

The physicochemical properties of compounds affect not only the transport of compounds in plants but also their penetration through the leaf cuticle. This topic is discussed in Chapter 8, and here only brief comment is made on the implications of penetration for subsequent transport. The influence of physicochemical properties on the movement of compounds across cuticles seems to be rather similar to that observed for membranes, in that compounds of intermediate lipophilicity (log Ko values of 1 to 3) appear to penetrate the most rapidly. Uptake of more polar and more lipophilic compounds can, however, be greatly increased by the use of appropriate surfactants. Acidic compounds are taken up relatively slowly, presumably because of poor penetration of the anions in consequence, they are often applied as esters which enter the plant rapidly and are then metabolized to the active acid. Thus, herbicides of a wide range of structures and physical properties are applied to plant foliage the use of surfactants and adjuvants increases the uptake of chemical into the leaf and hence its availability for transport via xylem and phloem but does not otherwise influence transport patterns. 

Uses Emulsifer, coupling agent for agric. pesticides and herbicides, emuision polymerization, metalworking lubricants, die-cast lubricants Properties Gardner 9 max. yel. cl. liq. ester-like odor sol. in most min. oils, aromatic solvents, low m.w. alcohols and ketones water-disp. sp.gr. 1.02 vise. 200 cps HLB 10.4 sapon. no. 97 flash pt. (PMCC) > 350 F 100% cone. 

Uses Emulsifier for agric. toxicants, ind. chlorinated insecticides and herbicidal esters primary emulsifier in emulsion polymerization of acrylic monomers, vinyl acetates, and vinyl acrylics textile antistet and lubricant cosmetics additive prin-cipai detergent in industrial alkaline deanersfor bottles, laundry, dairy, aircrafL metai, steam, or electrolytic deaning paint and stripping agent solvent cleaner Properties Yel. d. liq. disp. in water sp.gr. 1.05-1.06 acid no. 100-120 (pH 5.5) ... 

Uses For fbrmuiation of emuisifiabie cones, of herbicides and pesticides may be used aione or in combination with other nonionic and/or anionic surf. act. agents Properties Pt-Co 200 max. hazy vise, iiq. soi. in water, aicohois, aromatics, simpie esters, chiorinated hydrocarbons, and giycoi ethers insoi. in aiiphatic soivs., min., vegetabie, and paraffin oii sp.gr. 1.06 vise. 4000 cP (20 C) HLB 14.3 pour pt. 18 C cioud pt. 89 C (1% aq.) pH 6-8 (1% aq.) 100% act. 

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