THE GEOCHEMISTRY OF NATURAL WATERS

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THE GEOCHEMISTRY OF NATURAL WATERS

• STRUCTURES, PROPERTIES, AND OCCURRENCE OF ORGANIC
  COMPOUNDS IN NATURAL WATERS - II
• CHAPTER 6 - Kehew (2001)
• Ethers, aldehydes, ketones and others

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LEARNING OBJECTIVES

• Continue learning how to classify and name
  organic compounds of relevance to aqueous
  geochemistry (aromatic hydrocarbons, halogenated
  hydrocarbons, alcohols, ethers, aldehydes,
  ketones, etc.).
• Learn about the behavior of organic contaminant
  plumes (petroleum, halogenated hydrocarbons).

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ETHERS - I

• Ethers - can be considered to be formed from
  water by replacing both hydrogens by carbon or a
  carbon chain, i.e., R-O-R.
• Employed as solvents, pesticides and
  manufacturing processes.
• Common in contaminant plumes generally not as
  mobile as alcohols.
• Names formed by naming the groups attached to the
  oxygen atom in alphabetical order and adding
  ether.
• Methoxy (-OCH3), ethoxy (-OC2H5), and phenoxy
  (-OC6H5).

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ETHERS - II
diethylether (ethoxyethane) A common anesthetic.
tetrahydrofuran (perhydrofuran) A common solvent.
methoxychlor 2,2-bis(4-methoxyphenyl) -1,1,1-tric
hloroethane An herbicide.
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ETHERS - III
chlorinated dibenzodioxins 2,3,7,8-tetrachlorodib
enzo b,e1,4-dioxin Among most toxic compounds
known. Occur as impurities in herbicides and
defoliants. Byproducts of incineration of
industrial chemicals. Very immobile in soil and
ground water.
methoxy tert butyl ether MTBE (1-methoxy-1,1-dimet
hylethane) Unleaded gasoline additive. Notoriously
mobile.
chlorinated dibenzofurans 1,2,6,7-tetrachlorodibe
nzob,dfuran
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ALDEHYDES - I

• Aldehydes - one of several classes of compounds
  containing the carbonyl group (-CO). The
  carbonyl group in aldehydes is bonded to only one
  carbon atom.
• The general formula is
• Naming is based on selection of the longest chain
  containing the carbonyl group and replacing the
  -e in the name of the chain by -al.
• Polar compounds relatively mobile in ground water.

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ALDEHYDES - II
formaldehyde (methanal)
isobutyraldehyde (2-methylpropanal)
cinamaldehyde (3-phenyl-2-propenal) (2E)-3-phenyl
prop-2-enal
benzaldehyde
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KETONES - I

• Ketones - contain a carbonyl group bonded to two
  carbon atoms.
• The general formula is
• IUPAC names are formed in the same way as for
  aldehydes, except that the suffix is -one and the
  location of the carbonyl group is designated by a
  number.
• Ketones are soluble and mobile.

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KETONES - II
acetone (2-propanone)
methyl ethyl ketone (MEK) (2-butanone) (butan-2one
)
methyl phenyl ketone (phenylethanone) (acetophenon
e) (1-phenyethan-1-one)
diphenyl ketone (diphenylmethanone) (benzophenone)
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OTHER ORGANIC COMPOUNDS - I

• Esters - The -OH group of a carboxylic acid is
  replaced by an -OR group.
• Amines - based on the structure of ammonia where
  one or more hydrogens are replaced by a carbon
  atom or carbon chain.

Ethyl acetate
Methylamine
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OTHER ORGANIC COMPOUNDS - II

• Anilines - Aromatic amines.
• Amino acids - Important components of proteins.
  Account for 1-3 of NOM. An amino group occurs on
  the carbon adjacent to the carbonyl carbon of a
  carboxylic acid group.

Aniline (phenylamine)
Leucine
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OTHER ORGANIC COMPOUNDS - III

• Thiols (mercaptans) - Contain the -SH group.
  Noted for their odor, they are the main component
  of skunk spray, and are added to natural gas as a
  warning device.
• Less soluble in water than alcohols.
• Sulfides - Have the structure R-S-R.

Methanethiol
diphenyl sulfide (phenylthiobenzene)