Aliphatic acids soils

Aliphatic acids such as butyric acid have been previously implicated as being allelopathic compounds (46, 47, 23). Chou and Patrick (23) isolated butyric acid from soil amended with rye and showed that it was phytotoxic. Hydroxy acids have also been shown to possess phytotoxic properties (48) but have not been implicated in any allelopathic associations. Since SHBA is a stereo isomer, and the enantiomer was not identified because of impurity, all bioassays were run using a racemic mixture. The D-(-) stereo isomer of SHBA has been isolated from both microorganisms and root nodules of legumes and is suspected to be a metabolic intermediate in these systems (49). It is likely that only one enantiomer was present in the extract therefore, the true phytotoxic potential of this compound awaits clarification of the phytotoxicity of the individual enantiomers. 

A wide range of simple aliphatic acids are ubiquitous in soils and plants. Amongst these are a number of di- and tri-carboxylic adds, oxalic (1), malonic (2), malic (3), tartaric (4) and citric (5), which are implicated as having metal-binding roles. 

Carbanate and aliphatic acid—a herbicide class with a soil persistence of approximately 3 months... 

Manley, E. Evans, L. (1986). Dissolution of feldspars by low-molecular-weight aliphatic and aromatic acids. Soil Science, 141, 106-12. 

Watteau F. and Berthelin J. (1994) Microbial dissolution of iron and aluminum from soil minerals efficiency and specificity of hydroxamate siderophores compared to aliphatic acids. Euro. J. Soil Biol. 30(1), 1-9. 

The key intermediate 59 required for the synthesis of sulfobacin A (59) is achieved successfully via a coupling reaction of aliphatic acid 57 and amino ester 58 using DEPC.23 Sulfobacin A is biologically active sulfonolipids isolated from the culture broth of Chryseobacterium sp. NR 2993 in a soil sample collected from Japan. 

Under anaerobic soil conditions, organic substrates are often not decomposed completely to carbon dioxide. Incompletely oxidized intermediates and end products toxic to plants often accumulate in waterlogged soils. These intermediates and end products include lactic acid, ethanol, acetaldehyde, and aliphatic acids such as formic, acetic, or butyric acid. Ethylene is also sometimes present in abnormally high concentrations in waterlogged or anaerobic soil. 

Manganese dioxide oxidized five common soil phenolic acids—vanillic (32), syrin-gic (33), ju-coumaric (34), ferulic (30), and sinapic (29) acids — although p-hydroxybenzoic acid (35) was inert (Lehmann et al., 1987). Salicylic acid (31), although strongly held by manganese oxide, was resistant to oxidation (McBride, 1987), as were several aliphatic acids such as citric, lactic, pyruvic and tartaric acids (Stone and Morgan, 1984). 

Aromatic polyesters, such as PET, PBT or PEN, are not degradable in the presence of microorganisms, while their copolyesters with aliphatic acids show some extent of biodegradability [28,81,82]. It was reported that copolyesters based on PBT and polyfbutylene adipate) (PBA) with about 35-55 mol % of terephthalic acid residues exhibited suitable mechanical and physical properties, as well as favorable biodegradability (film approx. 100 pm degradation within 8-12 weeks in soil or compost). Beside copolymerization, the biodegradable properties of polyesters can be improved by increasing the hydrophilicity, for instance by the introduction of... 

Figure 10.13 Weight loss of films of different aliphatic-aromatic copolyesters in soil at ambient temperature and mature compost at 60 °C, film thickness 100 pm [13], components E = 1,2-ethanediol, P = 1,3-propanediol, B 1,4-butanediol, A adipic acid, T terepthalic acid both nnmbers at the end of the identification reflect the ratio of aromatic/aliphatic acid component in mol%, (e.g., ETA38 62 copolyester from 1,2-ethanediol, adipic acid and terephthalic acid with 38 mol% terephthalic acid in the acid component). PTA39 61-copolyester from 1,3-propanediol, adipic acid and terephthalic acid with 39 mol% terephthalic acid in the acid component BTA34 66 copolyester from 1,4-butanediol, adipic acid and terephthalic acid with 34 mol% terephthalic acid in the acid component...

Behaviour and fate of chlorinated aliphatic acids in soil. 

Dalapon (CH3CCI2COOH) and TCA (CCI3COOH) are the main aliphatic acids used. They are quite strong acids of intermediate lipophilicity, having pKa values of 1.8 and 0.65 respectively. Both are rapidly taken up by roots and shoots, inhibiting growth at the root tips and apical meristem. While dalapon is well translocated in the apoplast and symplast, TCA is transported more in the apoplast than in the symplast. Thus, dalapon is usually applied to foliage whereas TCA is applied to soil. 

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