{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}


biodegradability - TA BLE 5-20 Fill-LES 0F THUMB FOR...

Info icon This preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: TA BLE 5-20 Fill-LES 0F THUMB FOR BIODEGRADABILITY Factors Branching — Highly branched compounds are more resistant to biodegradation. ii 2i 3] Unbranched side chains on phenolic and phenoxv compounds are more easily mtaimlized than branch aikyi moieties [164]. 2,4—Didilorophenoxyalkanates with side chains of 4 or more rbons degraded easily, the propionate more slowly, and the dichlorophenoxyacetate not at all by a Flamhecterium 5p. {99] . Branched alkyl benzene sulionates degrade more siowly than straight-chain [155] . Chain Length — Short chains are not as quickly degraded as long chains. 1] 2i 3] 4] Si 5} Rate oi oxidation oi straight-chain aliphatic hydrocarbons is correlated to length of chain [39]. Soil micros attack long—chain mononuclear aromatics faster than fluid-Chain [152] . Micros grow on normal alkanes from noctane to n-eicosane but not an nAhept-ane to methane [43] . Sulfatereducing bacteria more rapidly degrade long-length carbon chains ldeoana to hentriaoontane} than short—length carbon chains [22] . ABS detergents increase in degradability with increase in chain length irom C6 to (.11 2 but not) C” [T1156]. Rate oIl mineralization of N in urea-formaldehwie complexes declines with Substitumts lNumbar at} on Simple Organic idolaqu ll 2i 3] 4} 5} 5i 3'} Alcohols, aldehydes, acids, esters, amides, and amino acids are more sus- ceptible to biodegradalion than the corresponding alkan-es, olefins. ketonea, dicarboxylic acids, nitrites, amines, and chioroalkanes [I18]. Increased substitution hinders oxidation responsible for breakdown of alkyl chains [5?! . No significant oxidation oi paiwyclic aromatic hydrocarbons containing more than three ring: 1104] . Longer persistence of chloroacetit: acids. til-substituted prooionic acids. isopropvl NAphenVicalbamllfl, and iwpmnvl phenylcarbamates with yeater number of {marines [Bl]. Diaminobenzene: show ten availability than mom-aminohentenes [9]. 0n aromatic ring: benzolc acid quit:le degraded; monochloro- Ind monofluoro hemoates are more resistant out can be degraded; di-, tri- and telra- are quite resistant. The more chlorides, the more resistant the compound [99] . Presence of more than one methyl group attached to a carbon strongly inhibits alkane utilization [1(1)] , Subttituants {Position oi} on Simple Organic Molecules “i l2} [3 q.- (5] [ii Branching Q": CH3— CH2 “an? — CH, —CH3 2:- {CH - CH CH3 0H OH > : CHQCH-‘iEI-Ha c” CH3 “ CH3 Chain Length CH3 - CH3— CH2— CH7- mi,— cu; — CH3 Schematic Examplea Sobstituonts {Number ol} C1430“ — CH3 — CH3 > NH? — tit-I2 -OOCIH > C‘H—CH 3 I 0 :9 CHJ—C—CHa cu; a CH; - cu: MHz—CH, I 0 CH I 3 2 — C\— CH: CHIC": > cna— on, — CH3 orig—cit, 4212431241 > on, —cH—ri:n ~fH— n a on or NH: # 5‘ —0'—~.* c n on; )v c | n Substituants lPositionII Factors Schematic Example“ Substituents {Position ofl [Conhl H H H 4i 0n the other hand, ortho isomers ol nitrophertols. methyianilines, sull'oneles of m. > No? l-phenyld-odecane, and chlorine-containing impropvl phenylcamonates are most Hi . NO? persistent [9, BI, 15?], 2 5] in fatty acids, introduction ol halogen or phenyl group on alpha carbon reduces cuiqct-tflficoott CHJICHngcl-lmml ' rate of degradation as opposed to same group on omega carbon [23, 3% . {Si 6} Parahtpdroxybenroale degrades more rapidly than ortho or meta [fewer micros 2’ degrade these] [148} . 7] For ABS. para sultonates are more readily degraded than ortho ultimate: of phen'vfdodecane and phanvltetradmne. In diheptybanzttno sulfonates the meta is man msoeptihle than the para substituent [156, 157] . CH2CICH3I1CH3 CH2ClCHalzCH3 . . . . . } l Bi NED-panrvl group addition inhibits aikane utilization ll carbon atom banded Is [3} CHJCHzéHCHICH2_fi machnch-Izcilrn next to last on the chain [IUD] . Stbstituunts [Type of} on Simpll Orpnic Malawi“ Subltittllnt {Type} Fl Mono- and dicarboxytic acids, aliphatic alcohols, and ABS are decreasingly CH3 d l egraded when hydrogen is replaced by methyl groups [34, 57, 155] . I” CH3 __ CH? _ mo" > at: _ (I: _ mo” CH3 CIII 2| Aliphatic acids are less easily degraded when chlorine replaces a hydrogen [3"]. {2] CI — (EH — E — OH > CI — c; - if .- OH C! 0 Cl 0 F3619?! Schematic Ettarnpllaa Substituentt [Two oil iComJ 5] Succefiive replacement at hydroxyls of cyanuric acid with amino groups make: compounds lass degradabte [Bl ] 7 El For naphthalene compounds, nuclei bearing single small allwi groups CH O [mflth ethyl or vinyl) oxidize at more rapid rate than those with a phenyl ~ I) g substituent [104]. ['51 g I-"I 3-phenvi -1.i-dimethvlurea [lenuronl is more rapidly degraded than 3-lp- chlorophenvllu . lrnonuroni. or Bile-dichlorophenvl]. . . ldiuron] i143] . NH: "NEH: "NCHacHa Ell N‘wb‘itItuunl methyl and ethyl groups in aniline-s are harder to oxidize [1}. In: Q } © > © 9i Behalogenalion may be specific for the halide substitucnt lo.g., achlom- propionate, not 3-hromo-: trihromoacetate. not tritluorol H519] . i9} cocoons“; :- arjccoocua ...
View Full Document

{[ snackBarMessage ]}