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I. HISTORY

The first soap

The earliest form of soap was created by a French chemist by the name of Michel

Eugène Chevreul and he made the first lump of soap in 1811, using fat, glycerin and fatty acids

as his ingredients. This is a formulation that is similar to the one that we use today, and while

earlier forms of “soap” existed, this version is the one that is used as a model for all modern

soaps.

Earlier version of soap

If you wanted to look at a more antiquated version of the invention of soaps, you’d

need to go way back to the period of the Babylonians in 2800 BC. In this account of soaps, no

real purpose or use for them is given, but a later account from 1500 BC in Egyptian culture

shows that there was a soap like substance that they used for washing, but it formed a paste

instead of a hand held bar like the kind people use today.

How we got the name “soap”?

Soap actually comes from the name Mount Sapo, which is a fictional mountain in Italy,

where the ash on the mountain was known to have some cleaning properties. The Romans gave

soap this name, and used it in many of their infamous bath-homes. They too mirrored the soaps

used by Egyptians and were a paste made of mostly ashes and clay. Soaps began to develop and

got better, until the fall of the Roman Empire, which eradicated almost all development in

hygiene products like soaps. This continued until the period of the Renaissance, where interest

in soaps began again.

Soap is never actually "discovered" , but instead gradually evolved from crude mixtures of

alkaline and fatty materials.

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Figure 1. Development of Soap

During the 1960’s and 1970’s, the composition of detergent underwent rapid

changes because of environmental considerations. Evidence indicates that phosphates from

detergents may contribute to the “eutrophication” of lakes. So the use of phosphates in

detergent was BANNED in some areas. Eutrophication is the ecosystem response to the

addition of artificial or natural substances, mainly phosphates, through detergents, fertilizers,

or sewage, to an aquatic system. Eutrophication is extremely costly to society and recovery

from eutrophication has been estimated to take a thousand years. One example is the "bloom"

or great increase of phytoplanktonin a water body as a response to increased levels of

nutrients. Negative environmental effects include hypoxia, the depletion of oxygen in the

water, which causes a reduction in specific fish and other animals.

1920’s & 1930’s

• From the original short-chain compounds the development has progressed through long chain alcohol sulfates.

1940’s • Through alkyl-aryl long chain sulfonates

1950’s &

1960’s

• To branched chaincompounds

1960’s

• The requirement of biodegradability become important and caused the return to linear long chains, because only the linear chain can easily biodegraded

1960’s & 1970’s

• The composition of detergent underwent rapid changes because of environmental considerations

1800’s

• Soap was believed to be a mechanical mixture of fat and alkali; then Chevreul a French chemist showed that soap formation was actually a chemical

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Figure 2. Eutrophication of river

Raw materials shortages at World War I led Germans to develop “synthetic

soaps” or detergents. These were composed of short-chain alkyl naphthalene sulfonates, which

were good wetting agents but only fair in detergent action. This sparked the interest worldwide

in developing detergents, and new developments are continuing to the present time.

Domeier completed his research on the recovery of glycerin from saponification

mixtures in this period . Until Leblanc’s important discovery producing lower price sodium

carbonate from sodium chloride, the alkali required was obtained by the leaching of wood

ashes or from the evaporation of naturally occurring alkaline waters. (e.g. Nile river)

II.SOAP AND DETERGENT

Soap & Detergent Differences

Detergents are synthetic compounds that have been created through a chemical

process. The most widely-used detergent, sodium lauryl sulfate, is created by reacting

sulfuric acid with dodecanol (a fatty alcohol) adding a few other chemicals, heating it up,

adding more chemicals, and so forth. On average, there are about ten steps between the

original raw materials and the final detergent.

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Soaps on the other hand, are created by mixing a fat (usually a vegetable oil) with

caustic soda (like lye or potassium hydroxide). Soaps have been created like this for

hundreds (maybe thousands) of years. Detergents, on the other hand, have only been

around for a few decades.

Difference in terms of reaction

Synthethic Detergents

Alkylbenzene + Oleum ----------> Alkylbenzene sulfonate

Tallow fatty alcohol + Oleum ----------> Fatty Alcohol Sulfate

Sulfonate + Sulfate + NaOH ----------> Sodium salts

Sodium salts + Builders, etc ----------> Detergents

Soap

Tallow + Hydrolysis (Splitting Fats) ----------> Tallow Fatty Acid

Tallow Fatty acid + NaOH ----------> Sodium salt of Fatty Acid

Salt of Fatty acid + Builder , etc. ----------> Soap

Difference In Action With Hard Water

Soap + Hardwater:

Form insoluble compounds with the calcium and magnesium ions present in hard

water. These insoluble compounds precipitate out and reduce foaming and cleaning action.

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Detergent + Hard water:

May react with the hard water ions, but the resulting products are either soluble or

remain colloidally dispersed in the water

Main Groups Of Detergent

1. ANIONIC

Anionic surfactants possess a negative charge on their hydrophilic end. This

charge helps the surfactant molecules to interact with both the fibers and soil particles, lifting

and suspending soils in “bubble-like” arrangements called micelles.

2. CATIONIC

Cationics have positively charged ends, which makes them ideal in antistatic

formulas like fabric softeners .

Also, cationic surfactants have antimicrobial characteristics, and they are found in

hard-surface disinfectants and cleaners. Formulas containing cationic surfactants cannot be

mixed with those containing oppositely charged anionic surfactants. The molecules would

interact with each other, producing a gooey mess that drops out of solution.

When reading the ingredients list, look for the

words “chloride” or “bromide” (as in alkylbenzene ammonium chloride) to identify cationics.

3. NONIONIC

Nonionic surfactants are also found in many cleaning products, including carpet

products. Nonionics have no charge on their hydrophilic end, which helps make them superior

oily soil emulsifiers.

Some nonionics are high foamers (like anionics), while others do not generate

much foam. Because of their lower foam profile and strong emulsifying potential, these

surfactants are the preferred choice when formulating extraction cleaners and pre sprays.

4. AMPHOTERRIC

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These unique molecules possess both a positive and a negative charge on their

hydrophilic end, giving them a net charge of zero.

Amphoteric surfactants have little utility on their own, but work extremely well in enhancing

the cleaning effect of both anionic and nonionic surfactants. They can serve as “coupling

agents,” which hold the surfactants, solvents and inorganic salt components of a formula

together.

Amphoterics are usually named in some way to indicate that they are

amphoterics, as in amphoterge. Other examples of amphoterics are betaines and amine

oxides.

Cleaning Process

Detergent molecules can aggregate in water into spherical clusters called Micelle. The

surfactants of both soap and synthetic detergents perform the primary cleaning and sudsing of the

washing action in the same way throught the reduction of surface tension.

Thoroughly wetting the dirt and the surface of the article being washed of the soap or

detergent solution.

Removing the dirt from the surface.

Maintaining the dirt in stable solution or suspension (Detergency)

In wash water soaps or detergents increase the wetting ability of the water so that it can

more easily penetrate the fabrics and reach the soil. Soil removal begins. Each molecules of the

cleaning solution may be considered a long chain. One end of the chain is hydrophilic (water-

loving); the other is hydrophobic (water hating or soil loving). The soil loving ends of some of

these molecules are attracted to soil particles away from the fabric and into the water.

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Figure 3. Soil removal process

Micelle

Detergent molecules can aggregate in water into spherical clusters called

Micelle.

The Hydrocarbon part of the molecules gather together on the inside of the micelle and

the polar groups are on the outside.

Oil-soluble water insoluble compounds such as dyes, are often into the center of the

micelle attracted by the hydrocarbon group. This process is known as solubilization.

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Figure 4. The Formation of a micelle

Detergent and soap have water attracting (hydrophilic) groups on one end of the

molecule and water-repelling (hydrophobic) groups on the other. These special properties used

in soil removal.

Figure 5. Soap and Detergent Molecule

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III. DETERGENT MANUFACTURING

Raw Materials

Figure 6. Raw materials in production of detergent

1. SURFACTANTS

Any compounds that affects (usually reduces) surface tension when dissolved in water

or water solutios, or which similarly affects interfacial tension between 2 liquids.

Soap; is such a material, but the term is most frequently applied to organic derivatives

such as; sodium salts of high molecular weight alkyl sulfates or sulfonates.

The surfactants of both soap and detergent perform the primary cleaning and sudsing

of the washing action in the same way the reduction of surface tension.

2. BUILDERS

Boost detergent power.

They prevent redeposition of soil from the wash water on fabrics.

EXAMPLES:

DETERGENT

Additives

Builders Surfactants

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sodium tripolyphosphates

tetrasodium phosphate

During 1960'sthe growth of algae and eutrophication in lakes became linked to the

presence of phosphates in detergents. Several states restricted phosphate use so that

substitute had to be found the 1st compound suggested was nitrilotriacetic acid (NTA), but was

declared carcinogen in 1970. but new research result have vindicated its safety in 1980.

3. ADDITIVES

Corrosion inhibitor protect metal and washer parts, utensils, and dishes from action

of detergent and water.

Anti-redeposition agents (Carboxylmethyl cellulose)

Tarnish inhibitors, carry the work on the corrosion inhibitor and extend protection to

metals such as German silver.

Fabric brighteners, are fluorescent dyes which makes fabrics look brighter because of

the ability to convert ultraviolet light to visible light.

Antimicrobial agents, Carbanilides, Salicylanildes and Cationics.

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Manufacturing Process of Detergent

Figure 7. Simplified continuous flowchart for the production of heavy-duty detergent

granules. (Procter & Gamble Co.)

SULFONATION-SULFATION. The Alkylbenzene is introduced continuously into the

sulfonator with the requisite amount of Oleum, using the dominant bath principle to control

the heat of sulfonation conversion and maintain the temperature at about 55oC. Into the

sulfonated mixture is fed the tallow alcohol and more of the Oleum.

All are pump through the sulfater, also operating on the dominant bath principle, to

maintain the temperature at 50-55oC, thus manufacturing a mixture of surfactantant slurry. The

surfactant slurry is conducted to storage.

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NEUTRALIZATION. The sulfonated sulfated products are neutralized with NaOH solution

under controlled temperature to maintain fluidity of the surfactant slurry. The surfactant slurry

is conducted to storage. The surfactant slurry, the sodium tripolyphosphate, and most of the

miscellaneous additives are introduced into the crutcher. A considerable amount of water

is removed, and the paste is thickened by the Tripolyphosphate hydration reaction.

Na5P3O10 + 6H2O Na5P3O10 * 6H2O

Sodium tripolyphosphate Sodium tripolyphosphatehexahydrate

The mixture is pumped to an upper story, where it is sprayed under high pressure into

the 24-m high spray tower, counter to hot air from furnace. Dried granules of acceptable shape

and size and suitable density are formed. the dried granules are transferred to an upper story

again by an air lift which cools them from 115oC and stabilizes the granules. The granules are

separated in a cyclone, screened, perfumed and packed.

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Alkylbenzene

+

Requisite amt. of Oleum

Sulfonator

Sulfater

Surfactant Storage

(Neutralize by NaOH Sol’n)

Surfactant Slurry

Crutcher

Sodium tripolyphosphate

Addititves

Drop Tank &

High Pressure Pump

Spray Tower

Dried Granules

Upper Story

Cyclone

Screen

Perfumed

Packing

Do

min

ant

Bat

h P

rin

cip

le

55

oC

Figure 8. Schematic Diagram of Detergent Manufacturing

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IV. SOAP MANUFACTURING

Soaps on the other hand, are created by mixing a fat (usually a vegetable oil) with

caustic soda (like Lye or Potassium hydroxide).

The Basic Chemical Reaction In Soap Manifacturing

3NaOH + (C17H35COO)3C3H5 3C17H35COONa + C3H5(OH)3

Caustic Soda Glyceryl Stearate Sodium Stearate Glycerin

Raw Materials

TALLOW

Tallow contains mixed glycerides obtained from the solid fat of cattle by steam

rendering. This solid fat is digested with steam; and tallow forms a layer above the water .

GREASE

Grease are obtained from hogs and small domestic animals and importance source of

glycerides of fatty acids. They are refined by steam rendering or by solvent extraction and are

seldom used without being blended with other fats.

COCONUT OIL

Soap from coconut oil is firm anfd lathers well. It contains large proportions of very

desirable glycerides of lauric and myristic acid

INORGANIC CHEMICALS

Inorganic chemicals such as caustic soda, salt, soda ash, and caustic potash, as well as

sodium silicate, sodium bicarbonate, and trisodium phosphate are added as builders.

Manufacturing Process of Soap

This is the process in making soap. The word milled refers to the fact that, during

processing, the soap goes through several sets of heavy rolls or mills which mix and knead it. A

much more uniform product is obtained, and much direct labor is saved.

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Figure 9. Making Soap in Milled Bars

As soap technology changed, continuous alkaline saponification was introduced.

Computer control allows an automated plant for continuous saponification by NaOH of oils and

fats to produce in 2 hours the same amount of soap (more than 300t /day) made in 2-5 days in

traditional batch method.

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Figure 10. Schematic Diagram of Soap Manufacturing

Other Manufacturing Process of Soap

Soap requires two major raw materials: fat and alkali. The alkali most commonly used

today is sodium hydroxide. Potassium hydroxide can also be used. Potassium-based soap

creates a more water-soluble product than sodium-based soap, and so it is called "soft soap."

Soft soap, alone or in combination with sodium-based soap, is commonly used in shaving

products.

Animal fat in the past was obtained directly from a slaughterhouse. Modern soap

makers use fat that has been processed into fatty acids. This eliminates many impurities, and it

produces as byproduct water instead of glycerin. Many vegetable fats, including olive oil, palm

kernel oil, and coconut oil, are also used in soap making.

Mixer

Chilling rolls

Dryer

Mills

Plodder

Cutter

Stamping

Wrapping

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Additives are used to enhance the color, texture, and scent of soap. Fragrances and

perfumes are added to the soap mixture to

Figure 11. The Kettle Process

The above illustrations show the kettle process of making soap. Cover the odor of dirt

and to leave behind a fresh-smelling scent. Abrasives to enhance the texture of soap include

talc, silica, and marble pumice (volcanic ash). Soap made without dye is a dull grey or brown

color, but modern manufacturers color soap to make it more enticing to the consumer.

The Manufacturing Process

The kettle method of making soap is still used today by small soap manufacturing

companies. This process takes from four to eleven days to complete, and the quality of each

batch is inconsistent due to the variety of oils used. Around 1940, engineers and scientists

developed a more efficient manufacturing process, called the continuous process. This

procedure is employed by large soap manufacturing companies all around the world today.

Exactly as the name states, in the continuous process soap is produced continuously, rather

than one batch at a time. Technicians have more control of the production in the continuous

process, and the steps are much quicker than in the kettle method—it takes only about six

hours to complete a batch of soap.

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The Kettle Process

BOILING

1 Fats and alkali are melted in a kettle, which is a steel tank that can stand three stories

high and hold several thousand pounds of material. Steam coils within the kettle heat the batch

and bring it to a boil. After boiling, the mass thickens as the fat reacts with the alkali, producing

soap and glycerin.

SALTING

2 The soap and glycerin must now be separated. The mixture is treated with salt,

causing the soap to rise to the top and the glycerin to settle to the bottom. The glycerin is

extracted from the bottom of the kettle.

STRONG CHANGE

3 To remove the small amounts of fat that have not saponified, a strong caustic solution

is added to the kettle. This step in the process is called "strong change." The mass is brought to

a boil again, and the last of the fat turns to soap. The batch may be given another salt

treatment at this time, or the manufacturer may proceed to the next step.

PITCHING

4 The next step is called "pitching." The soap in the kettle is boiled again with added

water. The mass eventually separates into two layers. The top layer is called "neat soap," which

is about 70% soap and 30% water. The lower layer, called "nigre," contains most of the

impurities in the soap such as dirt and salt, as well as most of the water. The neat soap is taken

off the top. The soap is then cooled. The finishing process is the

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Figure 12. The Continuous Process

Developed around 1940 and used by today's major soap-making companies, the above

illustrations show the continuous process of making soap.

The Continuous Process

SPLITTING

1 The first step of the continuous process splits natural fat into fatty acids and glycerin.

The equipment used is a vertical stainless steel column with the diameter of a barrel called a

hydrolizer. It may be as tall as 80 feet (24 m). Pumps and meters attached to the column allow

precise measurements and control of the process. Molten fat is pumped into one end of the

column, while at the other end water at high temperature (266°F [130°C]) and pressure is

introduced. This splits the fat into its two components. The fatty acid and glycerin are pumped

out continuously as more fat and water enter. The fatty acids are then distilled for purification.

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MIXING

2 The purified fatty acids are next mixed with a precise amount of alkali to form soap.

Other ingredients such as abrasives and fragrance are also mixed in. The hot liquid soap may be

then whipped to incorporate air.

COOLING AND FINISHING

3 The soap may be poured into molds and allowed to harden into a large slab. It may

also be cooled in a special freezer. The slab is cut into smaller pieces of bar size, which are then

stamped and wrapped. The entire continuous process, from splitting to finishing, can be

accomplished in several hours.

MILLING

4 Most toiletry soap undergoes additional processing called milling. The milled bar

lathers up better and has a finer consistency than non-milled soap. The cooled soap is fed

through several sets of heavy rollers (mills), which crush and knead it. Perfumes can best be

incorporated at this time because their volatile oils do not evaporate in the cold mixture. After

the soap emerges from the mills, it is pressed into a smooth cylinder and extruded. The

extruded soap is cut into bar size, stamped and wrapped.

V. BYPRODUCTS

Glycerin is a very useful byproduct of soap manufacture. It is used to make hand lotion,

drugs, and nitroglycerin, the main component of explosives such as dynamite.

Glycerin

Glycerol (also called glycerine or glycerin) is a simple polyol (sugar alcohol) compound.

It is a colorless, odorless, viscous liquid that is widely used in pharmaceutical formulations.

Glycerol has three hydroxyl groups that are responsible for its solubility in water and

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its hygroscopic nature. The glycerol backbone is central to all lipids known as triglycerides.

Glycerol is sweet-tasting and generally considered non-toxic.

Production

Approximately 950,000 tons per year are produced in the United States and Europe;

350,000 tons of glycerol were produced per year in the United States alone from 2000–

2004. Production will increase as the EU directive 2003/30/EC is implemented, which requires

the replacement of 5.75% of petroleum fuels with biofuel across all Member States by 2010, as

glycerol is a byproduct in the production of biodiesel. It is projected that by the year 2020,

production will be six times more than demand.

Hydrolysis process description to produce fatty acid and co-product glycerol:

This technique is advance in controlling the separation process and high recovery of glycerol in

single process cycle.Zinc oxide catalyst is used during the hydrolysis step that takes place when

water along with high-pressure steam is made contact with counter flow of oil in a separating

column. 5 Mpa pressure and 250-260oC temperature are maintained in the column. Liquid-

liquid contact column is used for this operation, from its bottom the separated glycerol is

removed continuously and from top fatty acids is sent to vacuum dryer and separator. Zinc

oxide and saponified fatty material is removed by the vacuum separator and to improve it

quality in colour and smell. Bottom stream from hydrolizer contains 15-20% glycerine, ZnO and

partially saponified fats. Glycerin is purified by ion exchange and concentrated in triple effect

evaporator to produce yellow glycerol, it is used for industrial application. It is reacted with

activated carbon to obtain white USP grade glycerin with 99% concentration.

Chemical reaction in hydrolyser

(R-COO)3C3H5 + 3H2O ↔ 3R.COO.H + C3H5(OH)3

Tri-glyceride + water ↔ fatty acid + glycerine (sweet water)

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Figure 13. Process flow Diagram of fatty acid and glycerol production from edible oil and fat

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VI. REFERENCES

Who Invented Soap? (2014). Retrieved on October 23, 2014 from

http://invention.yukozimo.com/who-invented-soap/

Eutrophication. (2014). Retrieved on October 23, 2014 from

http://en.wikipedia.org/wiki/Eutrophication

Micelle. (2014). Retrieved on October 23, 2014 from

http://en.wikipedia.org/wiki/Micelle

Anionic, nonionic, cationic — what do they all mean? (2014). Retrieved on October 23,

2014 from http://www.cleanfax.com/articles/anionic-nonionic-cationic-mdash-what-do-they-

all-mean

Glycerin. (2014). Retrieve last October 23, 2014 from

http://en.wikipedia.org/wiki/Glycerol

Continuous process to produce fatty acid and co-product glycerol from oils and fats

(2014). Retrieved on October 23, http://www.inclusive-science-engineering.com/continuous-

process-to-produce-fatty-acid-and-co-product-glycerol-from-oils-and-fats/

Cavitch, Susan M. The Natural Soap Book: Making Herbal and Vegetable-Based

Soaps. Storey Communications, 1995.

Maine, Sandy. The Soap Book: Simple Herbal Recipes. Interweave Press, 1995.

Spitz, Luis, ed. Soap Technologies in the 1990s. American Oil Chemists Society, 1990.

Austin, George T. Shreve’s Chemical Process Industries. 5th Edition USA.