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Alkyl benzene sulfonates

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Alkyl Benzene Sulfonates Gisha G.P MSc Biotechnology Mahatma Gandhi University, Kottayam Environmental Impact and Remedies
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Page 1: Alkyl benzene sulfonates

Alkyl Benzene Sulfonates

Gisha G.PMSc

BiotechnologyMahatma Gandhi

University, Kottayam

Environmental Impact and Remedies

Page 2: Alkyl benzene sulfonates

Introduction • Domestic waste water is one of the important

pollution sources affecting the water quality

adversely in many countries.

• Waste waters containing detergents are the

basic constituents of organic pollutants and they

cause great environmental damages by

introducing into the soil, lakes and rivers.

Page 3: Alkyl benzene sulfonates

• Detergents are the mixtures of surfactants and

their isomers and preferred to soap because of

their many superior properties. As a result of

economic development and population growth,

environmental problems caused by detergents

are increasing day by day.

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Chemistry …..• Alkyl benzene sulfonates are the major

components of anionic detergents.

• alkyl benzene is a family of organic compounds with the formula C6H5CnH2n+1.

• Typically, n lies between 10 and 16, although generally supplied as a tighter cut, such as C12-C15, C12-C13 and C10-C13, for detergent use .

• This molecule has a polar( sulfonate ) and non polar(alkyl) end.

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• Alkyl benzene sulfonates classified into 2

groups:

branched and linear chain

Page 6: Alkyl benzene sulfonates

• Type of substance : organic acid sodium salt

• Physical state(20ºC): solid

• Molecular weight: 342.4

• Vapour pressure(25ºC) : 3x10-13 Pa

• Boiling point : 637ºc

• Melting point: 198.5ºc

• Water solubility: 250g/l

• Density : 1.06kg/l

• pH (5%LAS soltn): 7-9

• Trade name: Marlon A

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ABS & LAS

• Linear and branched alkylbenzene sulfonates (LAS and ABS) are the most important anionic surfactants widely used in the formulation of house hold detergent and industrial cleaning products.

• The concentration of this anionic material in the detergent industries wastewater is too high and discharges generate critical problems and unrestorable damages such as poisoning of waterlife , pollution of ground water, and formation of foams in rivers.

Page 8: Alkyl benzene sulfonates

• Although ABS was an effective detergent it has slow rate of biodegradation in the environment.

• It become apparent that ABS based detergent were contributing to pollution of lakes and streams by forming relatively stable foams .

• Resistance of branched ABS to biochemical degradation in aquatic environments also posed to threat to municipal drinking water supplies , which were using surface water as a source for drinking water production.

Page 9: Alkyl benzene sulfonates
Page 10: Alkyl benzene sulfonates

• LAS was first commercialized in 1965s as a replacement for the poorly biodegradable Alkylbenzene Sulfonate (ABS) which caused persistent foam in sewage treatment plants, streams and rivers. LAS was the first surfactant introduced to solve an environmental problem.

• LAS has been shown to affect the flora and fauna of aquatic ecosystems. It has been observed that this compound denatures proteins in the cell membrane, altering the permeability of the membrane to nutrients and other chemical substances , but it can readily destroyed by microbial action.

Page 11: Alkyl benzene sulfonates

Manufacturing route

• The first ABS was obtained by the Friedle-Crafts alkylation of benzene with polyproplenetetramer. The tetramer is a mixture of C12 olefins. As a result the corresponding ABS is highly branched .

• The detergent produced is then sulfonatedwith oleum or sulfer trioxide followed by neutrilization with NaOH or soda ash.

• LAS is comprised of linear alkyl carbon chains (C10-C13), SO3- and Na+. LAS is made from kerosene and benzene through Linear AlkylBenzene (LAB) with further sulphonation

Page 12: Alkyl benzene sulfonates
Page 13: Alkyl benzene sulfonates

Human health assessment

• The toxicological data show that LAS was

not genotoxic in vitro or in vivo.

• The critical adverse effect identified after

repeated long term high dosing of LAS to

animals was a change in renal

biochemical parameters.

Page 14: Alkyl benzene sulfonates

Environmental risk assessment

Aquatic

• Toxicity tests have been conducted with LAS on a wide

range of fresh and saltwater fish, invertebrates and

algae.

• Acute toxicity of LAS to most fish and invertebrates is in

the 0.5 mg/L to 20 mg/L range.

• The aquatic toxicity of LAS to algae has a greater spread

of responses, with 90% of the species having an EC50

between 0.1 mg/L and 100 mg/l .

• The alkyl chain length affects the acute toxicity of LAS.

The EC50 for the different chain lengths of LAS to

Daplznia magna were found to be 0.68, 2.6, 5.9, 21.2

and 27.6 mg/L for the C14, C13,C12, C11,and C10 LAS

Page 15: Alkyl benzene sulfonates

Sediment

• The results from the U.S.G.S. study indicate that LAS concentrations in the sediment are more than five times lower than the lowest NOEC reported for the most sensitive species tested.

• The data indicate that LAS is not impacting sediment organisms in spite of the large wastewater input and the lack of secondary treatment by several large metropolitan cities along the river.

Page 16: Alkyl benzene sulfonates

Biodegradation

• Destruction of chemical by the metabolic

activity of micro organisms

• LAS are biodegadable surfactants.

Page 17: Alkyl benzene sulfonates

• Mechanism of breakdown involves the

degradation of the straight alkyl chain, the

sulphonate group and finally benzene ring.

• Alkyl chain breakdown starts with the

oxidation of the terminal methyl group( -

oxidation) through alcohol, aldehyde to

carboxilic acid.

• The reaction is catalyzed by alkane

monooxygenase and two dehydrogenase.

Page 18: Alkyl benzene sulfonates
Page 19: Alkyl benzene sulfonates
Page 20: Alkyl benzene sulfonates

• The carboxylic acid undergoes -oxidation

and two carbon fragment enters TCA cycle

as acetyl CoA.

• In case of ABS , the side chain methyl

group cannot undergo -oxidation by

micro organisms

• Second stage of breakdown , is the

degradation of sulphonate group.

Desulphonation occurs through either of

the 3 proposed way:

Page 21: Alkyl benzene sulfonates
Page 22: Alkyl benzene sulfonates

• Breakdown product of LAS is sulphite ,

and is oxidised to sulphate in the

environment.

• Loss of alkyl and sulphonate group from

LAS leaves either phenylacetic or benzoic

acid

• Microbial oxidation of phenylacetic acid is

fumaric and acetoacetic acids and

benzene is converted to catechol

Page 23: Alkyl benzene sulfonates

• The complete biodegradation of

surfactants requires a consortium of

bacteria due to the limited metabolic capacities of individual microorganisms.

• Consortium of bacteria comprises of

Pseudomonas aeroginosa, Bacillus

subtilis, Bacillus aglomerans, Bacillus

cereus, Bacillus alvae

Page 24: Alkyl benzene sulfonates

• Cultures isolated from the fresh water

layer of river had greater ability to degrade

LAS than those from the underlying saline

water layer.

• Degradation rates was faster for the

longest alkyl chain LAS and slower for

isomer having the sulphophenyl group

situated in the middle of the alkyl chain.

Page 25: Alkyl benzene sulfonates

Literature cited• Biodegradation of Surfactants in

the Environment. Matthew J

Scott , Malcom N Jones

• FATE OF THE BENZENE RING OF

LINEAR ALKYLBENZENE

SULFONATE IN NATURAL

WATERS . R. J. Larson* and A. G.

Payne ., APPLIED AND

ENVIRONMENTAL

MICROBIOLOGY.

• BIODEGRADATION OF LINEAR

ALKYL BENZENE SULFONATE

BY BACTERIAL CONSORTIUM.

Praswasti PDK Wulan, Misri

Gozan, Anondho W, Dianursanti,

Mahmud S

• MICROBIAL METABOLISM OF

. A. J. Willetts and R. B. Cain., Biochem. J. (1972)

• LINEAR ALKYLBENZENE

SULFONATE TOLERANCE IN

BACTERIA ISOLATED FROM

SEDIMENT OF TROPICAL WATER

BODIES POLLUTED WITH

DETERGENTS. Kehinde I.T.

Eniola & Albert B. Olayemi

• LAS -Linear Alkylbenzene

Sulphonate , Revised

ENVIRONMENTAL Aspect of the

HERA Report February 2013

• Linear Alkylbenzene Sulphonate -

The Soap and Detergent

Association

Page 26: Alkyl benzene sulfonates

Thank you


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