The fate and effects of oils in the enviroment

(1)

ENVIRONMENTAL CHEMISTRY

EPM II

Lecture on

The fate and effects of oils in the enviroment

Jan Hupka

Department of Chemical Technology

OILS

Generic (Lat. genus – kind) relating to or descriptive of an entire group or class; general; not having a trademark or trade name.

(3)

Types of oils

• hydrocarbo n-based

oils

• non-

hydrocarbo n synthetic oils

• renewable oils

•cutting oils

(4)

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).

(5)

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 alkylated aromatics

long-chain alkylcykloalkanes

(6)

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

(7)

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-based oils

(8)

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.)

(9)

Non-hydrocarbon synthetic oils

• polyglycol fluids

• diesters of dibasic acids

• polyesters – esters of polyhydroxyalkohols

• phosphate esters

• alkylated aromatics, e.g. dialkylbenzenes

• silicones

(10)

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

(11)

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

(12)

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.

(13)

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

(14)

Renewable oils

There are three main classes of oils that are derived from renewable biological materials:

• Vegetable oils

• Essential oils

• Fish oils

(15)

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

(16)

Renewable oils

C

H₃ COOH

C COOH H₃

C

H₃ COOH

C

H₃ COOH

C

H₃ COOH

oleic acid, [(9Z)-octadeca-9-enoic acid]

linoleic acid, [(9Z,12Z)-octadeca-9,12-dienoic acid]

linolenic acid, [(all-Z)-octadeca-9,12,15-trienoic acid]

palmitic acid, (hexadecanoic acid)

stearic acid, (octadecanoic acid)

unsaturated acids saturated acids Unsaturated acids lower the melting point of TAGs

(17)

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

(18)

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

(19)

Renewable oils

Essential oils

Some of examples of compounds occurring in essential oils

CH₃

C H₃

CH₃

C H₃

CH₃ C

H₃

C H₃

O

CH₂CH=CH₂

OH

OMe

CH₃ O

H CH₃ CH₃

(+)-α-pinene (-)-α-pinene (+)-camphor eugenol (+)-(Z)-α-santalol

(20)

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