Complete degradation

Heating isoxazole derivatives with aqueous-alkaline permanganate leads to a complete degradation of the heterocycle. With arylisoxa-zoles this results in readily identifiable aromatic acids, from which can be deduced the orientation of electrophilic substitution reac-tions. ° Also, the stability of various heterocycles can be compared. Thus, under these reaction conditions, the pyrazole ring is more stable than that of isoxazole (cf. 197198). ... 

Complete degradation of organocoppet aggregates may ocair when diey react widi tertiary pbospbines. Hiis is illustrated by treatment of arylcoppet compounds widi bis-fdipbetiylpbospbino)mediane fDPPM) and widi 1,2-bis-fdipbenylpbospbino)-ediane fDPPE) fsee Sdieme 1.11). 

A medium containing bile salts such as lithocholic add along with carbohydrates and peptone has been used to isolate gut organisms. One such isolate has been shown to completely degrade the lithocholic add (structure given in Figure 9.1). 

In the modified OECD Screening Test (OECD 301E), which indicates complete degradation or elimination according to the German Chemical Substances Control Act, alkanesulfonates are biodegradable to 95% (decrease in DOC, the dissolved organic carbon). 

In disc form, when prepared by compression molding, the more hydrophobic polymers, PCPP and PCPP-SA, 85 15, displayed constant erosion kinetics over 8 months. By extrapolation, 1-mm-thick discs of PCPP will completely degrade in over 3 years. The degradation rates were increased by copolymerization with sebacic acid. An increase of 800 times was observed when the sebacic acid concentration reached 80%. By altering the CPP-SA ratio, nearly any degradation rate between 1 day and 3 years can be achieved (4). 

Stndies of the antoxidation of carotenoids in liposomal suspensions have also been performed since liposomes can mimic the environment of carotenoids in vivo. Kim et al. stndied the antoxidation of lycopene," P-carotene," and phytofluene" " in liposomal snspensions and identified oxidative cleavage compounds. Stabilities to oxidation at room temperature of various carotenoids incorporated in pig liver microsomes have also been studied." The model took into account membrane dynamics. After 3 hr of reactions, P-carotene and lycopene had completely degraded, whereas xanthophylls tested were shown to be more stable. 

The sulfonyl urea sulfometuron methyl is stable at neutral or alkaline pH values, but is hydrolyzed at pH 5 to methyl 2-aminosulfonylbenzoate that is cyclized to saccharin (Figure 1.21) (Harvey et al. 1985). The original compound is completely degraded to CO2 by photolysis. 

Cook AM, R Hiitter (1984) Deethylsimazine bacterial dechlorination, deamination and complete degradation. J Agric Food Chem 32 581-585. 

For complete degradation of an aromatic hydrocarbon to occur, it is necessary that the products of ring oxidation and fission can be further degraded to molecules that enter anabolic and energy-producing reactions. 

Benchmark 4 Prefer - Safer Chemical. Only organic chemicals with low inherent toxicity to humans and wildlife, that do not bio accumulate, and rapidly and completely degrade to benign degradation products or metabolites reach Benchmark 4. These are chemicals that would meet the principles of green chemistry that relate to hazard. 

STABREX Stabilized Liquid Bromine9 is far more stable than liquid chlorine bleach. For example, several tons of the new product were shipped to India and stored for one year above 90 °F. The product remained within specification (less than 10% degraded) for the entire year, after which it was successfully used to control fouling in an industrial water system. Chlorine would have completely degraded in this time under these conditions. Chemical wastage was eliminated. Accident risk in transporting oxidant was reduced because less volume was necessary. Table 2 shows the stability of the new product compared to industrial strength chlorine bleach in well-controlled laboratory tests. 

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