CHE 321 – OLEOCHEMICALTECHNOLOGY

Afiqah Tasneem Binti AbdKhalil

2013487008

EH110 4A

FATTY ALCOHOLS

WHAT IS FATTY ALCOHOLS?o Fatty alcohols (or long-chain alcohols) - usually high-molecular-weight, straight-chain primary alcohols, but can also range from as few as 4-6 carbons to as many as 22-26, derived from natural fats and oils.

oSome commercially important fatty alcohols are lauryl, stearyl, and oleyl alcohols. They are colourless oily liquids (for smaller carbon numbers) or waxy solids, although impure samples may appear yellow.

oUsually have an even number of carbon atoms and a single alcohol group (-OH) attached to the terminal carbon. Some are unsaturated and some are branched.

oFatty alcohols - oleochemicals derived from vegetable feedstocks. The feedstock raw materials include coconut and palm kernel oils. These refined vegetable oils are first converted to a methyl ester or fatty acid. This reaction generates crude glycerine.

oThe intermediate methyl ester or fatty acid are then fractionated and hydrogenated to produce fatty alcohol. Alcohols are often distilled and fractionated to achieve the chain length distribution that meets

PRODUCTION PROCESS- Acid Route

- Ester Route

- Wax Ester Route

1) ACID ROUTE

o Based on the routes given in the previous slide, fatty alcohols can be produced from acid route, ester route and wax ester route.

o Through Acid Route, oil or fat first go through pre-treatment, splitting and then fractionation. The side product of the splitting go to another process, which is glycerine recovery to produce glycerine.

o From fractionation, fatty acid is produced and they go through slurry hydrogenation. Lastly, the products go again through fractionation to produce the final products, which is fatty alcohol.

2) ESTER ROUTE

Production using Fatty Acid Methyl Esters

oThe process of production of fatty alcohols from natural fats and oils via Fatty Acid Methyl Esters and Fatty Esters is selected.

oFor Fatty Acid Methyl Esters (FAME) , the process primarily involves Transesterification of oil with methanol to form FAME and a byproduct glycerin (80% pure) .The FAME thus obtained is hydrogenated to form fatty alcohol and methanol.

oThe fatty alcohol thus produced can be reacted with phosphorous pent oxide to form mono alkyl phosphates.

TRANSESTERIFICATION

Transesterification - is the displacement of the alcohol from an ester by another alcohol in a process similar to hydrolysis, except that an alcohol is used instead of water. This reaction, cleavage of an ester by an alcohol, is more specifically called alcoholysis and is represented by the general equation:

oIn this case, a new ester is formed. Generally, alkaline catalysts are used with sodium methylate said to be the most effective, although sodium hydroxide can also be used.

oTransesterification is an equilibrium reaction. To shift the reaction to the right, it is necessary to use a large excess of alcohol or to remove one of the products from the reaction mixture.

oThe second option is preferred where feasible, the reaction can be driven to completion. Transesterification is a general term. More specifically, if methanol is used, the reaction is termed methanolysis. But other alcohols can be used.

oTransesterification of fats and oils is the most commonly used process for manufacture of methyl esters, except in cases where methyl esters of specific fatty acids are needed.

oTriglycerides can readily be transesterified batchwise at atmospheric pressure and at a slightly elevated temperature of approximately 333-343 K with an excess of methanol and in the presence of an alkaline catalyst.

oThe mild reaction conditions requires the removal of free fatty acids from the oil by refining or pre-esterification before transesterification.

oThis pretreatment is not required if the reaction is carried out under high pressure of 9000 kPa and high temperature of 513 K. Under these conditions, simultaneous esterification and Transesterification take place.

oThe mixture at the end of the reaction is allowed to settle. The lower glycerin layer is drawn off whereas the upper methyl ester layer is washed to remove entrained glycerine and is then processed further.

oExcess methanol is recovered in the condenser, sent to a rectifying column for purification, and recycled. Continuous transesterification is well suited for large capacity requirements.

HYDROGENATION

oThe fractionated methyl esters can be converted into fatty alcohols by the high-pressure hydrogenation process in the presence of a catalyst. Usually, copper chromite catalyst is used.

oCopper chromite catalyst also converts any unsaturated carbon double bonds so that only saturated fatty alcohols are formed. If unsaturated fatty alcohols are desired, a special zinc-bearing catalyst is employed.

oThe hydrogenation process is carried out at 25,000–30,000 kPa and a temperature of 523–573 K in a tubular column. Depending on the method by which the catalyst is employed, the hydrogenation can be conducted using the suspension process or the fixed bed process.

PRODUCTION USING FATTY ESTERS

oFor the production of C12–C14 alcohols, only coconut oil and palm kernel oil can be used. Palm oil, soybean oil and tallow are the main sources for C16–C18 alcohols. Rapeseed oil is mainly for fatty alcohols with 20 or 22 carbon atoms.

oContaminants such as phosphatides, sterols or oxidation products and impurities such as seed particles, dirt and water were removed during pre-treatment of triglyceride.

oThe refined triglycerides are then transesterified with lower alcohols to yield fatty acid esters. The refined fatty acid esters (mostly methyl esters and, more rarely, butylesters) are used for hydrogenation to produce fatty alcohols.

Hydrogenation process of Fatty Ester to produce fatty alcohols Methyl esters or fractionated methyl esters can be converted into fattyalcohols by the high pressure hydrogenation process in the presence ofcatalyst.

Usually, copper chromite catalyst is used. Copper chromite catalyst alsoconverts any unsaturated carbon double bonds so that only saturated fattyalcohols are formed.

If unsaturated fatty alcohols are desired, a special zinc catalyst isemployed.

3) WAX ESTER ROUTE

o Its almost the same with the other routes, where oil and fats go through pretreatment, splitting when the side product glycerine is produced, fractionation when the fatty acid is produced.

o And then, a little bit difference where the fatty acid go through esterification to produce wax ester. Wax ester then undergo fixed bed hydrogenation process and fractionation again to give fatty alcohols as the final product.

FIXED BED PROCESSo Has the catalyst ‘‘fixed’’ as a bed inside the reactor. The catalyst is either compact pelletized or supported on a carrier.

o The reaction is conducted in vapor phase where a part of the organic feed is vaporized in an excess of hydrogen gas (20–25 moles) through a peak heater before passing through the fixed catalyst bed.

o Hydrogenation is carried out at 20,000– 30,000 kPa and 200–250°C. The reaction mixture leaving the reactor is cooled and separated into the gas and liquid phases.

o The gas phase, mostly excess hydrogen, is recycled. The liquid phase is expanded into a flash tank to strip off the methanol from the fatty alcohol.

o Operating conditions are comparatively mild, so that fatty alcohol produced does not require further processing. The overall yield is 99% hydrocarbons and unreacted ester not exceeding 1.0%. Catalyst consumption is claimed to be below 0.3%.

DERIVATIVES OF FATTY ALCOHOLS

- Alkyl polyglycolethers- Alkylsulfates- Alkyl polyglycolethersulfates - Alkyl methylammoniumchlorides - Alkyl polyglucosides

Raw materials

(Fats/Oil)

- Tallow

- Coconut Oil

- Palm Oil

- Palm Kernel Oil

Primary Oleochemicals

Fatty Alcohols

Oleochemical Derivatives

- Alkyl polyglycolethers

- Alkylsulfates

- Alkyl polyglycolether sulfates

- Alkyl methylammonium

chlorides

- Alkyl polyglucosides

o Fatty alcohols and their derivatives are used at about 70% in surface active substances and in addition in polymers, oil additives, cosmetics and have many specialty uses.

Alkyl polyglycolethers (fatty alcohol polyglycolethers, fatty alcohol ethoxilates) - the first nonionic surfactants which were manufactured in technical scale. For synthesis of this substance class, fatty alcohols are reacted with ethylene oxide in a base-catalyzed reaction. In addition, the fatty alcohol alkylenoxide adducts have to be mentioned, which are also manufactured in a base-catalyzed reaction of fatty alcohols, ethylen oxide and propylen oxide. The latter, in comparison to the first mentioned compounds, are low-foaming surfactants.

Alkylsulfates (fatty alcohol sulfates) - belong to the group of anionic surfactants and to the longest known synthetic surfactants. To synthesize this class of compounds, fatty alcohols reacted with SO3, chlorosulfonic acid, oleum or sulfuric acid. The resulting semi-esters are subsequently neutralized with an alkali base, mostly NaOH.

Alkyl polyglycolether sulfates (fatty alcohol ether sulfates) - also belong to the group of anionic surfactants. For the synthesis, fatty alcohols reacted with ethylenoxide and the resulting adducts are caused to react with sulfuric trioxide or chlorosulfonic acid. The subsequent neutralization is usually carried out using caustic soda, ammonia or ethanolamine.

Alkyl methylammonium chlorides - belong to the group of cationic surfactants and are produced using fatty alcohols especially in the range of C16-18 .

Alkyl polyglucosides (APG) - manufactured from fatty alcohols and sugar molecules following various procedures. They are kind to the skin and, if necessary, can be manufactured from renewable raw materials only. However, high production costs are usually a limiting factor.

USES OF FATTY ALCOHOLS IN INDUSTRY

REFERENCES

• http://noweck.com/vortrag_fatty_alcohols_karlsruhe_2011.pdf

• http://en.wikipedia.org/wiki/Fatty_alcohol

• http://www.pgchemicals.com/products/fatty-alcohols/

• http://raavviraaj9.blogspot.com/

That’s All. Thank You