Download OILS

ENVIRONMENTAL CHEMISTRY
EPM II
Lecture on
The fate and effects of oils in the enviroment
Jan Hupka
Department of Chemical Technology
Recommended reading
A. Kołodziejczyk, „Oils in the environment”,
Proceedings of the 4th International Conference on Oils and Environment,
June 20-23, 2005, Gdańsk
OILS
• Oil is a generic term for a
chemical compound that is
not soluble in water and is
liquid at ambient temperature
• Oils exhibit hydrophobic or
lipophilic properties
• Oils differ from fats and
waxes by the length of
molecular chain
• Emulsifiers allow mixing oils
with water to form an emulsion
Generic (Lat. genus – kind) relating to
or descriptive of an entire group or
class; general; not having a trademark
or trade name.
•
hydrocarbo
n-based
oils
• nonhydrocarbo
n synthetic
oils
• renewable
oils
•cutting oils
Types of oils
Hydrocarbons as a major component of oils
The majority of commercial oils consist mainly of hydrocarbons.
They predominate in the following oily products:
• fuels (gasoline, diesel oil, mazout)
• heating (furnace) oil
• engine oils and other lubricants
• transmission, turbine and hydraulic liquids, drawing oils, etc.
All of them are complex mixtures of straight chain alkanes
(n-alkanes), branched chain alkanes (isoalkanes), cycloalkanes
(naphthenes) and arenes (aromatics).
Hydrocarbons as a major component of oils
CH3(CH2)16CH3
C18H38
octadecane - an example of a group of straight-chain alkanes (n-alkanes), formerly
called paraffins
branched alkane (isoalkane)
short-chain alkylcykloalkane
long-chain alkylcykloalkanes
alkylated aromatics
Hydrocarbon-based oils
Mineral oils
• Products of atmospheric or vacuum distillation of petroleum
(contain hydrocarbons of longer chain than gasoline)
• Chemically inert, transparent, colorless liquids composed
mainly of alkanes and cyclic paraffins,
• Used as lubricants and diesel oils
Hydrocarbon-based oils
Transformer oil
• Usually a highly-refined mineral oil that is stable at high
temperatures and has excellent electrical insulating
properties. It is used in oil-filled transformers, some types of
high voltage capacitors, fluorescent lamp ballasts, and some
types of high voltage switches and circuit breakers. Its
functions are to insulate, suppress corona and arcing, and to
serve as a coolant.
• Prior to 1970, polychlorinated biphenyls (PCB) were
used as a dielectric fluids due to their high resitance to
the breakdown
• Today, nontoxic, stable silicone-based or fluorinated
hydrocarbons may be used, where the added expense of a
fire-resistant liquid offsets additional building cost for a
transformer vault
Hydrocarbon-base oils
Tar oils
• Products of the distillation of coal tar
• Depending on boiling point: light, carbolic, naphthalenic,
anthracenic tar oils
• Depending on application: impregnation, washing, flotation tar
oils
• Tar oils are the source of aromatic compounds (benzene,
naphthalene etc.)
Non-hydrocarbon synthetic oils
• polyglycol fluids
• diesters of dibasic acids
• polyesters – esters of polyhydroxyalkohols
• phosphate esters
• alkylated aromatics, e.g. dialkylbenzenes
• silicones
Non-hydrocarbon synthetic oils
Polyglycols
• Polyglycols are represented by several polymers, including
polyethylene glycol and polyethylene glycol dimethyl ether
• They have good lubricity, a high viscosity index, and are stable
in high temperatures
• They have been applied as automotive hydraulic fluids,
industrial gear oils, metal working fluids, and gas compressor
oils
• Most polyglycols are soluble in water and their solutions in
water serve as fire resistant fluids.
Non-hydrocarbon synthetic oils
Diesthers of dibasic acids
•
Diesters of long-chain alcohols and dibasic acids provide
excellent lubricity in low temperature, low volatility, high flash
point, and good thermal stability
• They are prone to hydrolysis so they have to work in
anhydrous conditions
• Diesters of dibasic acids are fluids recommended for aircraft
engines and compressors, as well as for preparation of
greases for use in low temperatures
• They easily undergo chemical and biological degradation
Non-hydrocarbon synthetic oils
Polyol esters
•
Polyol esters are prepared by acylation of polyols (diols, triols
or tetraols)
• They are show higher thermal stability and a much lower
coefficient of friction than lubricants based on mineral oils
• Currently, modern jet aircrafts almost obligatorily use
lubricating oils based on polyol esters. They are also used for
gas turbines working in high temperature and for preparing
hydraulic and heat exchange fluids.
Non-hydrocarbon synthetic oils
Silicones (R3SiO(SiR’R’’O)nSiR3)
• They are water sensitive and easily undergo transformation to
an abrasive polymerised product
• Silicones have a high viscosity index, high thermal stability,
and good low temperature performance
• They are used as a component of certain greases, torsion
dampers and automotive brake fluids
• They are not very popular as lubricants because they are
unserviceable for steel surfaces
Renewable oils
There are three main classes of oils that are derived
from renewable biological materials:
• Vegetable oils
• Essential oils
• Fish oils
Renewable oils
• Both vegetable and fish oils are triacylglycerols
(TAGs) which belong to the same chemical group of
compounds as esters of polyols
• Triacylglycerols are made up usually of different fatty
acid residues, with a varying number of carbon
atoms (chain length) and number of double bonds
(mono- or polyunsaturated acids), with various
proportion in a given fat (oil)
• Triacylglycerols are obtained mainly by extraction of plant
and animal oily parts and are called fats when they are
solids or oils when they are liquids
Renewable oils
Unsaturated acids lower the melting point of TAGs
COOH
H3C
oleic acid, [(9Z)-octadeca-9-enoic acid]
H3 C
COOH
H3C
palmitic acid, (hexadecanoic acid)
COOH
COOH
H3C
stearic acid, (octadecanoic acid)
linoleic acid, [(9Z,12Z)-octadeca-9,12-dienoic acid]
COOH
H3C
linolenic acid, [(all-Z)-octadeca-9,12,15-trienoic acid]
unsaturated acids
saturated acids
Renewable oils
Fish oils
• Fish oils are characterised by a considerable
contribution of polyunsaturated acids, so they are very
unstable and smell badly
• The poly-unsaturated acids occurring in fish oils belong to
essential fatty acids (EFA) and are an excellent
supplementary source of these acids in case of their
deficiency in a mammalian organism
• Triacylglycerols from fatty fishes contain unique w-3-polyunsaturated fatty acids (eicosapentaenoic acid – EPA and
docosahexaenoic acid – DHA), which are able to lower
the number of heart and arthritis diseases very effectively
Renewable oils
Essential oils
• Natural compounds produced by plants and accumulated
in their special structures such as oil cells, glandular hair,
cavities of heartwood, and oil or resin duct glands
• They may occur in different parts of plants, e.g. in flowers,
fruits, leaves, stems, wood, bark, or roots and are
obtained by pressing of plant parts, water-steam
distillation, solvent or fat extraction, and the newest way –
by supercritical fluid extraction which is considered the
most effective
• Chemically the components of EOs are hydrocarbons,
alcohols, esters, ethers, ketones, or even peroxides,
whose parent compounds are mainly mono- or
sesquiterpenes (dimers or trimers of isoprene).
Renewable oils
Essential oils
Some of examples of compounds occurring in essential oils
CH3
CH3
H3C
H3C
(+)-α-pinene
H3C
CH3
CH2CH=CH2
CH3
CH3
H3C
H3C
(-)-α-pinene
H3 C
OMe
O
(+)-camphor
OH
eugenol
CH3
HO
(+)-(Z)-α-santalol
TREATMENT OF OIL POLLUTION DEPENDS ON THE
FORM OF OIL PRESENCE IN THE ENVIRONMENT
Forms of oil/solvent presence in the environment:
• vapor
• mist (aerosol)
• dissolved
• dispersed (emulsified)
– colloidal
– solubilized
– suspended
– multiple emulsions (e.g. fire fighting wastewater)
• free-floating (bulk)
• water-in-oil emulsion
• oil-solid aggregates
In many cases several forms occur simultaneously