A) SOAP & DETERGENT

I) Definition of Soapo Soap are sodium or potassium salts of long-chain carboxylic

acidso The general formula of a soap : RCOO Na / RCOO K

R is an alkyl group which contain 12 to 18 carbon atoms.

II) The history of soap manufacturing.

Solvay Process- Carbon dioxide ( obtained from heating CaCo ) is passed into concentrated NaCl solution which is saturated with ammonia .NaCl +NH +H O + CO – Na HCO +NH Cl- NaHCO is then heated to obtain soda.2NaHCO – Na CO +H O +CO .

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Babylonians made soap around 2800 B.C.

Purifying oils is recorded on Hebrew Tables around 4000 B.C.Ash + Lime – Caustic potashCaustic Potash + fats – soap

Process of making soap ashes or sodium carbonate from common salt is patented by Nicholas Leblane (French).

Sodium carbonate Na CO is produced cheaply & used for glass making , soaps and detergent.

After 20 years, Ernest Solvay ( Belgian Chemist) developed Solvay process.

Michel Chevreul (French) discovered animal fats are cmposed of fatty acids and glycerol ( Causes rapid development of soap & candle.)

Later on, vegetables oil is used to replace animal fats.

III) Preparation of Soap by Saponification

Saponification is a process whereby the soaps are prepared by hydrolyzing fats or oils under alkaline conditions. It is also the alkaline hydrolysis of esters using alkaline solutions.

Fats/ Vegetable oils + concentrated alkalis – soap + glycerol(Fats- tallow from cow)( Vegetable oils – palm oil or olive oil)

For example,- Glyceryl tristearates

is a naturally occuring esters found in fats or oils.

Example of soap,1) sodium palmitate, C H COONa2) Sodium oleate, C H COONa3) Sodium stearate, C H COONa

To enhance the soap’s marketability,additives are used such as perfume, colouring matter and antiseptic. Production of soap can be precipitated by adding common salt to the reaction mixture in order to reduce the solubility of soap in water. Properties of soap depends on

a) type of alkali used for saponificationb) type of animal fats or vegetable oils used

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CH COOC H

CHCOOC H + 3 NaOH(concentrated alkali)

CH COOC H(glyceryl tristearate)

3C H COONa + CH OH( sodium stearate)Soap CHOH

CH OH(glycerol)

Potassium soap are softer, milder than sodium soap which can be used for bathing.

IV) Structure of soap molecule. When soap is dissolved in water, it will dissociate and produce sodium

ions and carboxylate ions. The active substances in soap is carboxylate ions which consists two

parts:a) the ‘ Head’1. negatively charged

2. contains the – C – O – ion3. is hydrophilic ( like to dissolves water)

b) the ‘Tail’1. positively charged2. is a long hydrocarbon chain3. is hydrophobic ( do not like to dissolves water)

I )Definition of DetergentDetergent is a synthetic cleasing agents which is made from hydrocarbons obtained from petroleum fraction.It is a kind of petrochemicals.There are 3 types of detergent which depends on the charge on detergent ion.a) Anionic Detergent.Head of the detergent particle contains a negatively charged ions.Example : R – O – SO NaDivide into two types:Sodium alkylbenzene sulphonate ( detergent molecule with a benzene ring)

R - - S – O Na R SO

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Sodium alkyl sulphate ( without a benzene ring)R – OSOb) Cationic DetergentHead of the detergent particle contains a positively charged ion.Example : R – N(CH ) Brc) Non- ionic detergentExample : R –O –CH CH OH

II) Preparation of DetergentSodium alkyl sulphate Sodium alkylbenzene sulphonates

- can be prepared from alcohols with chain lengths of 12 to 18 carbon atoms.- Step 1:Reaction with Concentrated sulphuric acid

Step 2 : Neutralisation with sodium hydroxide solution

Starting materials - long chain alkene, RCH = CH , obtained from the cracking of petroleum.Step 1 :Alkylation ( introduction of the alkyl group to an organic molecule)

Step 2 :Sulphonation ( introduction of the sulphonic acid group to an organic molrcule to form sulphonic acid)

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Sodium alkyl sulphate Sodium alkylbenzene sulphonates

Example :Dodecan - 1- ol, CH (CH ) CH OHDetergent prepared from dodecan – 1 – ol is called sodium dodecyl sulphate / sodium lauryl sulphate

Step 3 :Neutralisation

III) The Structure of Detergent Molecule When a detergent is dissolved in water, it dissociates to form sodium ions

and detergent ions. It consists of two parts:a) the ‘ Head’ (sulphate group, - OSO / sulphonate group - SO)

1. negatively charged2. hydrophilic ( like water)

b) the ‘Tail’ ( long hydrocarbon chain)1. neutral2. hydrophobic ( hates water)

The cleansing action of soap and detergentThe cleansing action of soaps and detergent results from

the ability to lower the surface tension of water, to emulsify oil/ grease and to hold them in suspension in water

This can be occurred due to their chemical bonding and the structure.Oil cannot be washed away from clothing with water only as it is a covalent molecule which is insoluble in water.

1. sodium soap dissolves in water to form soap (-ions) and sodium (+ions).

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2. Anion consists of a long hydrocarbon chain with a carboxylate group on one end.3. the hydrocarbon (hydrophobic)soluble in oil/ grease.4. carboxylate group (hydrophilic) soluble in water.

Process of the cleaning action of soap and detergent. A piece of cloth is stained with grease and then dipped into

soap/ detergent water.

Through this, the wetting ability of water increases.

Thus, the surface of cloth is wetted thouroughly.

The hydrophobic part of the soap/ detergent anion dissolve in grease while the hydrophilic part is attracted to water molecule.

Because of the forces of attraction between water molecules and negatively-charged heads, the grease begins to be lifted off the surface when the water is agitated slightly.

Mechanical agitation during scrubbing helps the process of emulsfication occurs whereby the grease is broken into small droplets.

The droplets do not coagulate and redeposit on the surface of the cloth due to the repulsion between the negative charges on th surface. These droplets are suspended in water to form emulsion. The droplets is rinsed and washed away and leave the surface clean.

IV) Additives in detergentsAdditives in detergent is used to increase their cleaning power and make the detergent more attractive and saleable.

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Additives Function Example

Builders To enhance the cleaning efficiency of detergent by softening the water.To increase the pH value of water.

Sodium tripolyphosphate

Drying agents To ensure that the detergent in powdered form is always in dry condition.To add to the bulk of the detergent and enable to pour it at ease.

Sodium sulphateSodium silicate

Fragrances To add fragrance to both detergent anf fabrics.

Foam control agents To control foaming in detergent.

Optical whitener To add brightness and whiteness to white fabrics.

Fluorescent dyes

Suspension agents To prevent dirt particles removed from redepositing onto cleaned fabrics.

Carboxymethylcellulose (CMC)

Biological enzymes To remove protein stains such as blood.To break down fat and protein molecules in food stains.

Amylases ,proteases, cellulases and lipases

Whitening agents To convert stains into colourless substances.To make the fabrics whiter and more beautiful.

Sodium perborateSodium hypochlorite (NaClO)

V) The effectiveness of soaps and detergents as cleansing agents

Cleansing agents

Advantages Disadvantages

Soap 1. very effective in soft water to wash clothes.( water does not contain Mg & Ca ions)2. Do not cause pollution as soaps are made from fats and oils and can be decomposed by the action of bacteria.

1. Ineffective in hard water.2. A grey scum (Magnesium stearate & calcium stearate) will be produced in hard water.

3. Not effective in acid water.( exist as

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molecules & do not have hydrophilic ends)- H ion from rainwater (acid) will react with soap ions to produce carboxylic acid molecules of large molecular size that are insoluble in water. Example,

Detergent 1. effective in soft water and hard water.( magnesium salt and calcium salts are formed aand soluble in water)( scum is not formed)

2. Synthetic cleansing agents- structure of hydrocarbon chain can be modified to produce detergent.3. effective in acidic water as H ions is not combine with detergent ions.

1. non-biodegradable2. water pollution occurs.3. Decrease in oxygen content in water and the aquatic lives are given the harm.( phosphates in detergents)4. a lot of foam will be produced in water that prevent oxygen from dissolving in water.As a result, fish and other aquatic lives face the death.5. Additives (sodium hypochlorite ) releases chlorine gas that is highly toxic and kills aquatic life.

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B) FOOD ADDITIVES

- Definition of Food Additives – are natural or synthetic substance which are added to food to:

i) prevent spoilage ii) improve its appaerance , taste or textureiii) prevent growth of microorganismsiv) prevent oxidation of fats and oils by oxygen in airv) restore the colour of food destroyed during food

processing.- Type of Food Additives and Their Functions1. Preservatives – substance added to food to slow down and prevent the growth of microorganisms in order to kepp the lasts longer.- salts, vinegar and sugar have been used for centuries to preserve food.

Preservatives Molecular Formula

Uses

Saltsugar

Drwas water out of the cells of microorganisms Retards the growth of microorganisms.

Vinegar Provides acidic condition that inhibits the growth of microorganisms.

Sodium nitriteSodium nitrate

NaNO NaNO

To preserve the meat, sausage, cheese and dried fish.To prevent food poisoning in canned food.To maintain the natural colour of meat. To make the meat look fresh.

Benzoic acidSodium benzoate

C H COOHC H COONa

To preserve sauces, fruit juice, jams and margarine.

Sulphur dioxideSodium sulphate

SO

Na SO

Used as antioxidants to prevent browning in fuits.Maintain the colour and freshness of vegetables.To prevent thr growth of yeast.

2. Antioxidants- added to food to i) pevent oxidation that causes rancid fats

and brown foodsii) to slow down the oxidation process.

- food containing fats or oils are oxidised and become rancid when exposed to air. This makes the food unpalatable. Th rancid products are volatile organic compounds with 4 odours.

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( exp : butanoic acid, C H COOH)

Antioxidants UsesButylated Hydroxyanisole (BHA)Butylated Hydroxytoluene (BHT)

To retard rancidity in oils.

Sodium citrate To stop fats from turning rancid.Vitamin C Inhibits the formation of carcinogeic nitrosamines.

Stimulates the immune systems.Protects against chromosome breakage.Preserve the colour of friut juice.

Vitamin E Neutralizes free radical compounds before the cell membrane are damaged.Reduce the risk of heart diseases and cancer.

3. Flavourings - Flavourings are the largest group of food additives.- Function : to improve the taste of food restore taste loss due to processing.- There are 2 types of flavourings :

i) Flavour enchancers- Flavor enchancers are chemicals that are added to food to bring

out the flavours/ to enhance the tastes of food.- Exp : monosodium glutamate (MSG)

MSG is a sodium salt of glutamic acid.It exists as solid fine white crystal.It is added to savoury prepared and processed

- frozen foods- spice mixes- canned and dry soups- salad dressings- meat and fish based products

In order to protect the public health, MSG is not allowed in baby foods and less used for the adults.

ii) artificial sweeteners Aspartame

Aspartame is a white , odourless powder, approximately 200 times sweeter than sugar.

It is used in a variety of foodstuffs.

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It is stable when dry or frozen but breaks down and loses its sweetness over a time when stored in liquids at temperature above 30.

Exp : diet drinks and soft drinks- Synthetic Essences

o contain chemicals which are made to resemble natural flavour.o Exp :pentyl ethanoate, CH COOC H – give banana flavour and is

cheaper to use.- Many of compounds are used to produce artificial flavours belong to the homologous series of esters.

4. Stabilizers- a substance which helps to prevent on emulsion ( oil /water droplets suspended in water/oil droplets) from separating out.- It is used in margarine, butter, ice cream and salad cream.- exp : lecithin, mono- and di-glycerides of fatty acids.

5. Thickeners- are chemicals that are added to food to thicken the liquid and to prevent the food from liquefying.- They absorb water and thicken the liquid in food to produce a jelly-like structure.- They are natural carbohydrates.- Exp:Thickeners ExplanationModified starch Used in instant soups and puddings.pectin Used in jams and jellies.

Forms a firm jel when there is sufficient sugar in a mixture.Is not digested.Can be considered as a beneficial and dietary fibre.

Acacia gum To thicken chewing gum, jelly and wine.Gelatine To thicken yogurt.

6. Dyes- chemicals that are added to food to give the colour so as to improve the appearance of food.- is used to add or restore the colour in food in order to

enhance its visual appeal match consumer expectations give colour to food that have no colour.

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- artificial food dyes are oftenly used as they are more uniform, less expensive and have brighter colours than natural food dyes.- many food dyes are

i) azo compounds ( red , orange, yellow)- orang drinks, custard powders, sweets and apricot jam.

iii) triphenyl compounds( blue-brilliant blue FCF, green)- main trend in colour of food towards the use of natural colours is anthocyanin.* found in red grapes, red cabbage sweet potatoes* have antioxidants properties.

Effect of Food Additives on Health.Effects ExplanationAllergy Caused by Sodium sulphite, BHA and BHT , MSG

and food dyes( yellow No.5). Cause an diseases named ‘ Chinese restaurant

syndrome’ (giddiness, chest pain and difficulty in breathing)

Cause ‘blue baby’ diseases occuring on babies which iits synptoms is lacking of oxygen and the presence of sodium nitrate /nitrite.

Cancer Caused by carcinogens(sodium nitrite) Nitrite reacts with amines to produce

nitrosamine( cause cancer)Brain damage Caused by excessive intake of nitrites.Hyperactivity Caused by tartrazine (additives)

Difficul to sleep or relax and felt restles.

The Rationale for Using Food Additives

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AdvantagesTo prevent food spoilage.

To improve nutritional value

Medical reasons

C) MEDICINE- medicine is a substance used to prevent or cure diseases or to reduce pain and suffering due to illness.- it is classified as

i) traditional medicine is a medicine derived from natural resources without being

processed chemically. Can be obtained from plants and animals. Any medicinal plant containing alkaloid is potentially toxic to

liver. Some of it interacts with medications resulting in serious side

reactions. Exp : garlic capsules combined with diabetes medication can

cause a sudden decrease in blood sugar

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Life without food additives

Food spoilage always occur

Diseases will occur oftenly

Malnutrition will occur particularly.

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ii) Modern Medicinethey usually contain a mixture of active ingredientsprepared in different forms such as capsules, pills, solution and suspensions.Exp: Alka-Seltzer (used as antacid) contains sodium bicarbonate (NaHCo ), citric acid and aspirin to neutralises the excess stomach acid.can be classified as follows based on their sffect on the human body :a) analgesics (painkillers)medicines that relieve pain without causing numbness or affecting consciousness.

Analgesics Uses Side effectAspirin Pain relief and anti-

inflammatory action. Acetyl salicylic acid (IUPAC

name) Contains 2 functional

groups(carboxylic acid/ester) Acidic.

oReduce feveroRelieve headaches,

muscle aches and joint aches.

oTreat arthritisoActs as an anticoagulant

– prevent clotting blood.o Reduce the risk of heart

attack and strokes.

Cause brain and liver damage of illed- children. Cause bleeding in the stomach. Cause allergy reactions, skin rashes, asthmatic attacks.

Paracetamol neutral

oTo relieve mild to moderate pain (headache,muscle and joint pain, backache , period pains)

oDoes not irritate the stomach to bleed.

Causes skin rashes, blood disorders and acute inflammation of the pancreas.

Cause liver damage.

Codeine Is an organic compounds that

contains carbon, hydrogen oxygen and nitrogen elements.

Uesd in headache tablets and cough medicine

Is synthesized from morphine

Is a nacortic drugs. Is a strong analgesics.

Cause addiction, depression, nausea, drownsiness

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b) antibioticsCemicals that destroy / prevent the growth of infected microorganisms.Will not cure the infection caused by viruses such as cold and flu.Obtained from bacteria/fungi.Broken down by acid in the stomach.Antibiotics Uses Side effectsPenicillin Derived from the mould

penicillium notatum

oTreat diseases caused by bacteria such as oneumonia, gonorrhoea, syphilis and tuberculosis.

Cause allergic reactions

Cause daeth for people who allergiuc at it.

Streptomycin Produced by soil and bacteris at the genus streptomyces

o Treat tuberculosis, whooping cough and some forms of pneumonia.

Cause nausea,vomitng, dizziness, rashes and fever. Loss of hearing following long term use.

c) psychotherapeutic medicines.A group of dugs for treating mental / emotional ilness.

Psychotherapeutic medicines Uses Side effectsStimulantsA medicine which activates the level of arousal and alertness of the central nervous system to reduce fatigue and elevate moon in most people.

i) AdrenalineA need in demanding energetic activities.ii) caffeineweak, naturally occuring stimulantfound in coffee, tea and cola drinks.iii) AmphetaminesStrong synthetic stimulantsIncrease alertness & physical ability.Increase the heart *repiration rates & blood pressure.

Cause addiction

AntidepressantsMedicine used primarily in the treatment of depression.

i) tranquilizersto clam down a personreduce tension & anxiety

cause drowsiness, poor coordination and light headedness, respiratory difficulties, sleeplessness, coma and death if overdose.

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i) BarbituaratesTo sedate, calm and relax individual in low doses.

Cause sleep (high dose)Cause addiction and habit formingCause death.

Antipsychotici) chlorpromazineii) haloperidoliii) clozapine

To treat psychiatrie illness such as schizophrenia (loses touch with reality)

Cause mild, dry mouth, blurred vision, urimary retention, constipation, tremor and less rrest as well as sedation(more clmer/sleepy)

! Drug Abuse – taking drugs excessively and without a doctor’s prescription.the examples of drugs are ectasy and ice.

D) THE EXISTENCE OF CHEMICALS

The chemicals for consumers such as soap, detergents , food additives and medicine play an important role in our life . However, they can contribute negative effects to our health and the environment if these chemicals are not used wisely .

Some proper management of these chemicals :-Detergents Wear gloves when working with strong detergents to protect your

hands . Use biodegradable detergents . Use appropriate amounts of detergents.

Food additives Be wise when we consume the food with food additives. Avoid consuming too much salt and sugar . Avoid foods with additives which you are sensitive to . Avoid rewarding children with junk food .

Medicines No self medication . Do not take medicine prescribed for someone else . Check for expiry date . Follow your doctor’s instruction for taking medicine . Keep away from children . Do not overdose .

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Intensive scientific research must be carried out to produce new substances and this takes more time . Scientists must patient and persevere for their research and development to produce new chemicals in future .

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