Aniline, degradation product

Aniline was first isolated in 1826 as a degradation product of indigo, a dark blue dye obtained from the West Indian plant Indigofera anil, from which the name aniline is derived. 

The complexity of the metabolism of alachlor, acetochlor, butachlor, and propachlor has led to the development of degradation methods capable of hydrolyzing the crop and animal product residues to readily quantitated degradation products. Alachlor and acetochlor metabolites can be hydrolyzed to two major classes of hydrolysis products, one which contains aniline with unsubstituted alkyl groups at the 2- and 6-positions, and the other which contains aniline with hydroxylation in the ring-attached ethyl group. For alachlor and acetochlor, the nonhydroxylated metabolites are hydrolyzed in base to 2,6-diethylaniline (DBA) and 2-ethyl-6-methylaniline (EMA), respectively, and hy-droxylated metabolites are hydrolyzed in base to 2-ethyl-6-(l-hydroxyethyl)aniline (HEEA) and 2-(l-hydroxyethyl)-6-methylaniline (HEMA), respectively. Butachlor is metabolized primarily to nonhydroxylated metabolites, which are hydrolyzed to DEA. Propachlor metabolites are hydrolyzed mainly to A-isopropylaniline (NIPA). The base hydrolysis products for each parent herbicide are shown in Eigure 1. Limited interference studies have been conducted with other herbicides such as metolachlor to confirm that its residues are not hydrolyzed to the EMA under the conditions used to determine acetochlor residues. Nonhydroxylated metabolites of alachlor and butachlor are both hydrolyzed to the same aniline, DEA, but these herbicides are not used on the same crops. 

Aniline is released in the presence of denitrifying and methanogenic microbial activity238b. The pKa value suggests that in moist soils, aniline will be protonated, and bound to soil, which inhibits degradation. Volatilization does not take place from dry soils, based on the vapor pressure. Studies have been made on the metabolism of aniline-derived products, such as herbicides and fungicides, in soil. Chloroanilines bind to organics in... 

Reaction of 2,3 4,5-di-0-isopropylidene-D-ribose with a lithiated aniline derivative gave the pentitol (11) and hence, after LAH reduction and hydrolysis, the deoxypentitol (12), which was shown identical to the degradation product from methanopterin, thus establishing the stereochemistry of the polyol in this compound. ... 

Lignin and its degradation products (coniferyl alcohol) can be identified by color reactions The addition of aniline hydrochloride gives a yellow color and the addition of a mixture of 1 g phloroglucine -h 25 ml hydrochloric acid -1- 50 ml water gives a cherry-red color. 

Chloroaniline was photochemically decomposed and the degradation products (cyclopenta-1,3-diene-1-carbonitrile, 2-aminophoioxazine-3-one, and three o-phenyl-disubstituted anilines such as 2-chloro-3-aminophenol) were extracted from water and separated on a C g column (A = 280 nm). A 60/40 methanol/water (with 1.8 g/L ammonium acetate) mobile phase resolved all compounds in < 15 min [102]. 

As an attempt to eliminate the formation of degradation products in the oxidized aniline monolayers, electrochemical oxidation of AnC6SH/Au and AnC7SH/Au was performed in 0.1 M LiClOVCHsCN from 0.0 to +0.9 V vs SSCE, Figure 7. The first oxidation scan for both monolayers produced an irreversible... 

Figure 3.3 Volatile degradation products in two oxidized polymers monitored by head-space GC. (a) Photo-oxidized LDPE with iron dimethyl dithiocarbamate and carbon black 1 = acetaldehyde 2 = methanol 3 = acetone 4 = 1-butanol 5 = butanol 6 = 3-pentanol. (b) Thermo-oxidized nylon 66 1 = acetaldehyde 2 = Cu-acetate 3 = cyclopentanone 4 = aniline.

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