Cátedra de Química Orgánica

Presentación del tema: "Cátedra de Química Orgánica"— Transcripción de la presentación:

1 Cátedra de Química Orgánica
Tensioactivos - Obtención de Jabón y Detergentes Aniónicos Cátedra de Química Orgánica

2 Comprobar la relación entre la estructura de la molécula y sus propiedades como tensioactivo a través de la obtención de dos detergentes de uso corriente. Ejemplificar la hidrólisis irreversible de los ésteres. Ejemplificar la obtención de ácidos grasos para su aplicación posterior. Ejemplificar una reacción de sustitución electrofìlica aromática y el efecto orientador del grupo alquilo. Incentivar en el alumno la conciencia de cuidado del medio ambiente.

3 Los agentes de tensión superficial tienen una estructura molecular particular que les confiere sus propiedades características. Surface active agents or surfactants have a distinct molecular structure that gives rise to their molecular properties. [extra background] Soaps such as sodium oleate are examples of a class of molecules called surfactants. The name "surfactant" comes from somebody who we don't think would spell very well - it actually stands for SURFace ACTive AgeNT. Both detergents and soaps are classed as surfactants. Surfactants are characterised by the essential features that we saw in sodium oleate. A surfactant molecule has a hydrophilic (water-loving) head and a long hydrophobic (water-hating or oil-loving) tail. For this reason, we often describe surfactants is being amphiphilic molecules - they love everything. Surfactants are said to have a "head" and a "tail". The head is hydrophilic which means that it is water loving, and it is generally depicted as a circle. The tail is generally a long hydrocarbon chain and is hydrophobic, which means water-hating (therefore oil-loving). The tail may be depicted either as a straight line or a wavy tail. Properties of Surfactants The molecular structure of surfactants means that they have unusual properties, leading to both widespread and highly specialised applications. The properties of surfactants fall into two broad categories: adsorption and self-assembly. Adsorption Adsorption is the tendency for a surfactant molecule to collect as an interface. Adsorption is very different to absorption (don't get them confused!): the taking up of a gas or liquid at the surface of another substance, usually a solid (for example, activated charcoal adsorbs gases). It involves molecular attraction at the surface. Absorption the taking up of one substance by another, such as a liquid by a solid (ink by blotting paper) or a gas by liquid (oxygen dissolving in water). The adsorption properties of surfactants mean that surfactant molecules are usually found at the interface between an oil phase and a water phase or a water phase and an air phase. This molecular property leads to the macroscopic properties of wetting, foaming, detergency and emulsion formation. Surfactant molecules tend to adsorb to the surface of oil droplets. The hydrophilic heads stick out into the water phase, while the hydrophobic tails happily stick into the oil phase. Self-Assembly Self-assembly is the tendency for surfactant molecules to organise themselves into extended structures in water. This includes the formation of micelles, bilayers and liquid crystals. These structures are formed by when the hydrophobic tails of the surfactants cluster together, forming small aggregates such as micelles, or large layer structures (bilayers) which are similar to a cell wall. These properties make surfactants very interesting study, and are areas of current research. Surfactants can aggregate to from micelles. Forming a micelle allows the hydrophobic tails to get out of the water but still allows the hydrophilic heads to stay in the water. There is usually between a few dozen to a couple of hundred surfactant molecules in a micelle. Surfactants also aggregate to form extended structures in water, such as the surfactant bilayer depicted here. The Key Centre for Polymer Colloids is established and supported under the Australian Research Council's Research Centres Program. To give us feedback or to obtain more information use our feedback form or contact Bob Gilbert. Copyright © Key Centre for Polymer Colloids. Last Modified: Tuesday January Cola (hidrofóbica) Cabeza (hidrofílica)

4 Propiedades Cabezas hidrófilas Agua Colas hidrófobas Aceite
Self-Assembly Self-assembly is the tendency for surfactant molecules to organise themselves into extended structures in water. This includes the formation of micelles, bilayers and liquid crystals. These structures are formed by when the hydrophobic tails of the surfactants cluster together, forming small aggregates such as micelles, or large layer structures (bilayers) which are similar to a cell wall. These properties make surfactants very interesting study, and are areas of current research. Surfactants can aggregate to from micelles. Forming a micelle allows the hydrophobic tails to get out of the water but still allows the hydrophilic heads to stay in the water. There is usually between a few dozen to a couple of hundred surfactant molecules in a micelle. Surfactants also aggregate to form extended structures in water, such as the surfactant bilayer depicted here. The Key Centre for Polymer Colloids is established and supported under the Australian Research Council's Research Centres Program. To give us feedback or to obtain more information use our feedback form or contact Bob Gilbert. Copyright © Key Centre for Polymer Colloids. Last Modified: Tuesday January Las propiedades de adsorción de los tensioactivos determinan que las moléculas se hallen habitualmente en la interfase entre una fase oleosa y una fase acuosa o entre una fase acuosa y una fase gaseosa (aire). Esta propiedad molecular conduce a las propiedades macroscópicas de humectación, espuma, detergencia y formación de emulsiones.

5 Propiedades de los Tensioactivos
Pueden agregarse formando micelas: las colas hidrofóbicas queden fuera de contacto con el agua y las cabezas hidrofílicas permanezcan en el agua. Hay habitualmente entre unas pocas docenas a doscientas moléculas de tensioactivo en una micela.

6 Propiedades de los Tensioactivos
También se agrupan para formar estructuras extendidas en agua, tal como la bicapa de surfactante mostrada en la figura.

7 Diferencias entre jabones y detergentes sintéticos
la estructura de la molécula la composición química el efecto en agua dura Los jabones y otros tensioactivos tienen propiedades muy diferentes en agua dura. La razón de esto es que los jabones tienen un grupo terminal carboxilato, que resulta de la hidrólisis de un ácido graso. El grupo carboxilato forma sales insolubles con los iones metálicos que se hallan en el agua dura (calcio y magnesio). Una de las fuerzas motoras para el desarrollo de los detergentes fue la necesidad de contar con moléculas de propiedades limpiantes similares a las del jabón, que no fueran sensibles a los iones metálicos del agua. Students learn to distinguish between soaps and synthetic detergents in terms of: the structure of the molecule chemical composition effect in hard water Soaps and other surfactants have very different properties in hard water. The reason for this is that soaps have a carboxylate end-group, which is a result of the hydrolysis of fatty acid. The carboxylate end-groups turn out to be particularly good at complexing (i.e. bonding to) metal ions, especially those found in hard water (e.g. calcium ions). This effect is all too familiar for our friends in Adelaide - the complexed metal ions (usually calcium) tend to precipitate out, giving the water a cloudy, murky appearance. (The cloudiness is due to the precipitation of surfactants, while the murky, brown colour is due to tannins in the water, just like weak tea.) Even more exciting for the residents of Adelaide, this precipitate can form a scum on the surface of the bath, the basin and anybody who steps into the water. One of the driving forces for the development of detergents was the need for molecules with soap-like cleaning properties that were insensitive to metal ions in the water. The Key Centre for Polymer Colloids is established and supported under the Australian Research Council's Research Centres Program. To give us feedback or to obtain more information use our feedback form or contact Bob Gilbert. Copyright © Key Centre for Polymer Colloids. Last Modified: Tuesday January 2, 2001

8 Propiedades de Jabones y Detergentes
La protonación del ion oleato para dar ácido oleico puede ocurrir a pH debajo de 4.5. La molécula es insoluble, sin carga y no actúa como tensioactivo (razón por la cual los jabones no son apropiados para usar en medio ácido). Properties of Soaps and Detergents As we have already seen, the principal difference between a soap and a detergent is the behaviour in hard water. Soaps tend to complex with the metal ions in hard water forming a scum, while detergents do not. Another difference between soaps and detergents is the sensitivity of soaps to acidic solutions. If you put a soap into and acidic solution (pH < 4.5), the carboxylate group will be protonated: The protonation of oleate ion to form oleic acid can occur at pH below 4.5. This forms an uncharged, insoluble molecule, which is not surface-active. The protonated soap molecule does not have a charged head, so it is no longer soluble in water. The soap molecules precipitate out forming a cloudy mixture, which (like hard water) leads to the formation of a scum. Soaps are not suitable for use in acidic conditions. Other common soaps: sodium palmitate, sodium myristate and sodium stearate. The Key Centre for Polymer Colloids is established and supported under the Australian Research Council's Research Centres Program. To give us feedback or to obtain more information use our feedback form or contact Bob Gilbert. Copyright © Key Centre for Polymer Colloids. Last Modified: Friday January 19, 2001 Otros jabones comunes: palmitato, miristato y estearato de sodio.

9 Clasificación Cuatro grandes categorías: Aniónicos, Catiónicos,
No iónicos Zwitteriónicos Students learn to distinguish between anionic, cationic and non-ionic synthetic detergents in terms of: - chemical composition - uses Surfactants are said to fall into four broad categories: anionic, cationic, nonionic, and zwitterionic. To help us understand the differences between these categories, we'll have a look at a number of different common surfactants and work out how to categorise them. As we go, we'll also have a look at how these different classes of surfactants are commonly used. It is interesting to note that all of surfactants we will look at here are synthetic surfactants - even the simplest all the surfactants (soap) is in fact synthesised from natural products. Soaps such as sodium oleate are only a couple of synthesis steps away from the original natural products but nonetheless they are man-made. The total US market for surfactants in 1993 was almost 5 × 109 kg, with a total value of $3.5 × 109. The size of this market makes for some quite competitive marketing and research. Between 1992 and 1994, around 1500 world patents were issued for cleaning products. [Source: Bartolo, R.G., Soap, in Encyclopedia of Chemical Technology, 4th ed, J.I. Kroschwitz, Editor. 1993, Wiley Interscience. p ] The Key Centre for Polymer Colloids is established and supported under the Australian Research Council's Research Centres Program. To give us feedback or to obtain more information use our feedback form or contact Bob Gilbert. Copyright © Key Centre for Polymer Colloids. Last Modified: Friday February 23, 2001 Difieren en composición química y usos.

10 Aniónicos La característica definitoria es que es un anión.
Palmitato de sodio (jabón) Alquil sulfato de sodio The defining feature of the anionic surfactant is, of course, that it is an anion (i.e. a negatively charged ion). All of the soaps (the fatty acid salts) are anionic surfactants (see the section on soaps for more information). Some common soaps: sodium oleate, sodium palmitate, sodium myristate and sodium stearate. One of the first steps in the development of surfactants that were insensitive to metal lines was the development of the alkyl sulfate surfactants. Like the soaps, these are anionic surfactants. In fact, probably the most studied surfactant over the years is one of these alkyl sulfates: sodium dodecyl sulfate (SDS). Unlike soaps, alkyl sulfates will not precipitate in low pH solutions. Sodium dodecyl sulfate, one of the most common of the alkyl sulfate style of anionic surfactant. Teacher Note: Unfortunately SDS is also sensitive to hard water. A sample of SDS to which calcium chloride is added tends to form a precipitate just like soaps. Since SDS is commonly used in wool-washing blends, dishwashing detergents and in washing powder, this has interesting consequences. Other commonly used anionic surfactants are the alkyl benzenesulfonates, alkyl sulfonates and the alkyl phosphates. Two alkyl phosphates, an alkyl sulfonate, and an alkyl benzene sulfonate Sulfosuccinates are similar to the alkyl sulfonates and were developed in 1939. The sulfosuccinate surfactant sodium di(2-ethylhexyl) sulfosuccinate (sold under the name Aerosol-OT or AOT). Uses of Anionic Surfactants Anionic surfactants are used all over the place. They make up around 49% of all surfactants made. They are used in shampoos, in dishwashing detergents and in washing powders. In many industrial and commercial applications, anionic surfactants are no longer used on their own. Typically, they are used in conjunction with nonionic surfactants to provide even greater stability. Long-term exposure to anionic surfactants has been linked to swelling of the skin in a conditioned allergic reaction. This swelling is temporary, although it tends to increase the susceptibility of the skin to permeation by other substances. Anionic surfacntants are generally avoided in cosmetic products, but their use in shampoos and other products can still lead to irritation (that's why some people suggest changing shampoos every month or so). The Key Centre for Polymer Colloids is established and supported under the Australian Research Council's Research Centres Program. To give us feedback or to obtain more information use our feedback form or contact Bob Gilbert. Copyright © Key Centre for Polymer Colloids. Last Modified: Thursday January 25, 2001 Alquil benceno sulfonato

11 Usos: Son usados en shampoos, en detergentes lavavajilla y en polvos para lavar. En muchas aplicaciones industriales y comerciales, los surfactantes aniónicos no son ya usados aisladamente. Típicamente se usan junto con no iónicos para proveer mayor estabilidad. The defining feature of the anionic surfactant is, of course, that it is an anion (i.e. a negatively charged ion). All of the soaps (the fatty acid salts) are anionic surfactants (see the section on soaps for more information). Some common soaps: sodium oleate, sodium palmitate, sodium myristate and sodium stearate. One of the first steps in the development of surfactants that were insensitive to metal lines was the development of the alkyl sulfate surfactants. Like the soaps, these are anionic surfactants. In fact, probably the most studied surfactant over the years is one of these alkyl sulfates: sodium dodecyl sulfate (SDS). Unlike soaps, alkyl sulfates will not precipitate in low pH solutions. Sodium dodecyl sulfate, one of the most common of the alkyl sulfate style of anionic surfactant. Teacher Note: Unfortunately SDS is also sensitive to hard water. A sample of SDS to which calcium chloride is added tends to form a precipitate just like soaps. Since SDS is commonly used in wool-washing blends, dishwashing detergents and in washing powder, this has interesting consequences. Other commonly used anionic surfactants are the alkyl benzenesulfonates, alkyl sulfonates and the alkyl phosphates. Two alkyl phosphates, an alkyl sulfonate, and an alkyl benzene sulfonate Sulfosuccinates are similar to the alkyl sulfonates and were developed in 1939. The sulfosuccinate surfactant sodium di(2-ethylhexyl) sulfosuccinate (sold under the name Aerosol-OT or AOT). Uses of Anionic Surfactants Anionic surfactants are used all over the place. They make up around 49% of all surfactants made. They are used in shampoos, in dishwashing detergents and in washing powders. In many industrial and commercial applications, anionic surfactants are no longer used on their own. Typically, they are used in conjunction with nonionic surfactants to provide even greater stability. Long-term exposure to anionic surfactants has been linked to swelling of the skin in a conditioned allergic reaction. This swelling is temporary, although it tends to increase the susceptibility of the skin to permeation by other substances. Anionic surfacntants are generally avoided in cosmetic products, but their use in shampoos and other products can still lead to irritation (that's why some people suggest changing shampoos every month or so). The Key Centre for Polymer Colloids is established and supported under the Australian Research Council's Research Centres Program. To give us feedback or to obtain more information use our feedback form or contact Bob Gilbert. Copyright © Key Centre for Polymer Colloids. Last Modified: Thursday January 25, The Key Centre for Polymer Colloids is established and supported under the Australian Research Council's Research Centres Program. Uses of Anionic surfactants Soaps The most common soaps are the ones shown previously. Since soaps are quite closely derived from natural products, they are quite impure. The typical composition of a couple of common classes of commercial soap are: Tallow soaps: 40-45% oleate, 25-30% palmitate, 15-20% stearate Coconut oil soaps (even more impure): 45-50% various C12 carboxylates, 16-20% various C14 carboxylates, 8-10% various C16 carboxylates, 5-6% oleate, 10-15% various C12 or shorter carboxylates You might be interested to know that a common brand of soap was named because it was derived from palm oil and olive oil (think about it...). The company that started as Palmolive, a soap manufacturer, has now grown to be a large multinational in the personal care industry, having merged with Colgate. In the 1940s, many applications that used to use soaps were altered to use the new synthetic detergents. The synthetic detergents were much better behaved in hard water than the soaps and gave superiour performance. Unfortuately, the detergents needed a small amount of phospate added to them to achieve this performance in many commercial applications (e.g. laundry detergents). The large amounts of phosphates that ended up in waterways in developed countries led to eutrophication (an algal explosion that consumes all the oxygen in the water leading to large-scale fish and plant death). Phosphates have largely been replaced in laundry detergents with other builders such as zeolites or polymers. Soaps are still used in small amounts in most laundry detergents to control the amount of suds produced and to reduce the transfer of dyes. Alkyl Sulfates The alkyl sulfates (like sodium dodecyl sulfate, SDS, shown previously) are commonly used surfactants. They have been found to have similar feel and emolliency properties to soaps. The applications of these surfactants are principally in shampoos, textile processing, emulsion polymerisation, laundry products and in carpet cleaners. (Their use in carpet cleaners is because many of them can make a rich foam that is low in water content.) Alkyl Sulfonates The alkyl sulfonates offer reasonable performance in hard water, although they do tend to form some complexes with calcium and magnesium ions. These surfactants are widely used in some industrial processes requiring anionic surfactants and are also used in low levels in some hand-dishwashing detergents. Sulfosuccinates Sulfosuccinates like AOT (pictured before) have proved to be quite useful surfactants. While ester linkage can be hydrolysed in harsh conditions, these surfactants are generally regarded as being mild and versatile. They are used when strong wetting, detergency penetration and solubilisation characterics are needed. (AOT is a good emulsifier and wetting agent.) Alkyl Benzenesulfonates The alkyl benzenesulfonates have the heaviest usage of the non-soap surfactants. These surfactants have almost entirely replaced soaps in household laundry products. Unfortunately, these surfactants are only slowly biodegradable, leading to a significant build-up of these surfactants in the environment (some water bodies had foam on top of them...). The commercial and industrial success of the alkyl benzenesulfonates is due in part to their performance and part to the low manufacturing cost. Apart from laundry products, they are widely used in hand-dishwashing and in hard surface cleaners. Alkyl Phosphates The calcium and magnesium salts of these surfactants are insoluble, so their performance in hard water is poor, and the ester linkage makes them unstable in acids. There are a number of applications for these surfactants, although they are normally only used in industrial processes where it is known that the water quality is sufficiently good. Their most common uses are in textile mills, industrial cleaning, dry-cleaing fluids and in the emulsion polymerisation of vinyl acetate. These surfactants have also been used as corrosion inhibitors in pesticides and in papermaking processes. [Source: Bartolo, R.G., Soap, in Encyclopedia of Chemical Technology, 4th ed, J.I. Kroschwitz, Editor. 1993, Wiley Interscience. p ] The Key Centre for Polymer Colloids is established and supported under the Australian Research Council's Research Centres Program. To give us feedback or to obtain more information use our feedback form or contact Bob Gilbert. Copyright © Key Centre for Polymer Colloids. Last Modified: Thursday January 25, 2001 La exposición prolongada a se ha asociado a hinchazón de la piel, consecuencia de una reacción alérgica condicionada.

12 Catiónicos La característica definitoria de un es que es un catión.
Like anionic surfactants, it is fairly easy to recognise the cationic surfactants - it has a positive charge. Fatty amine salts (or ammonium salts) were developed as the first cationic surfactants. Fatty amine salts were the first style of cationic surfactant synthesised. Unfortunately, ammonium salts can also be sensitive to pH. If we take these cationic surfactants up to high pH (10 or 11) then it is possible to deprotonate the amine, thus leaving us once again with an uncharged molecule. In the same way as the fatty acid salts tended to precipitate out once they were protonated, these fatty amine salts will precipitate out once deprotonated. In response to this shortcoming, the alkyl pyridinium and quaternary ammonium salts were developed (quaternary means that there are four substituents on the nitrogen atom). These surfactants are incredibly stable so that they do not lose their charge in high pH conditions. The development of alkyl pyridinium and quaternary ammonium salts provided excellent surfactants that could be used over a vast range of conditions. Uses of Cationic Surfactants Cationic surfactants are typically used in things like hair-conditioner and fabric softeners. The fatty amine salts proved quite useful in blends with nonionic surfactants, giving good stability over a range of pH levels. Cationic surfactants are generally rated as being more irritating to the skin than anionic surfactants (although this is probably a gross over-generalisation...). You might be interested to know that having a "bad hair day" is usually due to residual surfactant on your hair. The cationic surfactants used in shampoos and hair-conditioners can stick to your hair even when you rinse it under water. This results in slightly positively charged hairs, which repel each other, giving you that "bad hair day" look. The Key Centre for Polymer Colloids is established and supported under the Australian Research Council's Research Centres Program. To give us feedback or to obtain more information use our feedback form or contact Bob Gilbert. Copyright © Key Centre for Polymer Colloids. Last Modified: Thursday January 25, 2001 Las sales de aminas grasas fueron los primeros sintetizados.

13 excelentes surfactantes que pueden ser usados en un rango amplio de
El desarrollo de sales de amonio cuaternario y de alquil piridinio produjo excelentes surfactantes que pueden ser usados en un rango amplio de condiciones.

14 Usos: Son típicamente usados como
acondicionadores para el cabello y suavizantes de tela. El amonio cuaternario es fuertemente hidrófilo. Estos son primariamente usados en suavizantes para tela, ya que las cabezas hidrófilas cargadas positivamente tienden a interactuar fuertemente con las fibras de la tela cargadas negativamente. Fatty Amine Salts The principle uses of the fatty amine salts are in ore-flotation, corrosion ihibition and wetting. They are rarely marketed on their own, rather in propritery formulations. Quaternary Ammonium Salts and Alkyl Pyridinium Halides The development of the pH insensitive cationic surfactants allowed much wider use of this technology. The quaternary amine is a strong hydrophile, making these good surfactants. They are primarily used in domestic farbic-softeners, as the positively charged hydophilic head tends to interact strongly with negatively charged fabric fibres. [Source: Bartolo, R.G., Soap, in Encyclopedia of Chemical Technology, 4th ed, J.I. Kroschwitz, Editor. 1993, Wiley Interscience. p ]

15 No iónicos Tradicionalmente han usado las cadenas de
polioxietileno como grupo hidrofílico. El polioxietileno es un polímero soluble en agua. Non ionic surfactants differ from both cationic and anionic surfactants in that the molecules are actually uncharged. The hydrophilic group is made up of some other very water soluble moeity, (e.g. a short, water-soluble polymer chain) rather than a charged species. Traditionally, nonionic surfactants have used poly(ethylene oxide) chains as the hydrophilic group. Poly(ethylene oxide) is a water soluble polymer; the polymers used in nonionic surfactants are typically 10 to 100 units long. The two common classes of surfactant that use poly(ethylene oxide) chains as their hydrophilic group are the alcohol ethoxylates and the alkylphenol ethoxylates. An alcohol ethoxylate and an alkylphenol ethoxylate. The poly(ethylene oxide) chain forms the water soluble surfactant "head". Another class of nonionic surfactants are the alkyl polyglycosides. For at least the last 20 years these have been dubbed the "new generation nonionic surfactants". In these molecules, the hydrophilic group is sugar - in this case they are just polysaccharides, but they can be made from disaccharides, trisaccharides, maltose and various other sugars. Examples of alkyl polyglycosides: an alkyl glucoside and a glucose ester. Although they are called polyglycosides, they generally only have one or two sugar groups in the chain. Sorbitan ester surfactants are commercially signicant surfactants. Fairly harsh conditions are required to synthesise them: °C in the presence of an acid catalyst. "Tween 85" (sorbitan trioleate poly(ethylene oxide)) is one of the sorbitan ester surfactants Uses of Nonionic Surfactants The predominant use of these surfacants is in foods and drinks, pharmaceuticals and skin-care products. It is thought that these surfactants are mild on the skin even at high loadings and long-term exposure (although they can lead to a weakening of the skin barrier by helping the transport of molecules. The Key Centre for Polymer Colloids is established and supported under the Australian Research Council's Research Centres Program. To give us feedback or to obtain more information use our feedback form or contact Bob Gilbert. Copyright © Key Centre for Polymer Colloids. Last Modified: Thursday January 25, 2001 En la figura se muestra un alcohol etoxilato y un alquilfenol etoxilato. La cadena de polioxietileno forma la cabeza soluble-

16 Alquil poliglicósidos: en los últimos 20 años han sido considerados la
"nueva generación de tensioactivos". En estas moléculas, el grupo hidrofílico es un azúcar : disacáridos, trisacáridos, maltosa y varios otros azúcares. Non ionic surfactants differ from both cationic and anionic surfactants in that the molecules are actually uncharged. The hydrophilic group is made up of some other very water soluble moeity, (e.g. a short, water-soluble polymer chain) rather than a charged species. Traditionally, nonionic surfactants have used poly(ethylene oxide) chains as the hydrophilic group. Poly(ethylene oxide) is a water soluble polymer; the polymers used in nonionic surfactants are typically 10 to 100 units long. The two common classes of surfactant that use poly(ethylene oxide) chains as their hydrophilic group are the alcohol ethoxylates and the alkylphenol ethoxylates. An alcohol ethoxylate and an alkylphenol ethoxylate. The poly(ethylene oxide) chain forms the water soluble surfactant "head". Another class of nonionic surfactants are the alkyl polyglycosides. For at least the last 20 years these have been dubbed the "new generation nonionic surfactants". In these molecules, the hydrophilic group is sugar - in this case they are just polysaccharides, but they can be made from disaccharides, trisaccharides, maltose and various other sugars. Examples of alkyl polyglycosides: an alkyl glucoside and a glucose ester. Although they are called polyglycosides, they generally only have one or two sugar groups in the chain. Sorbitan ester surfactants are commercially signicant surfactants. Fairly harsh conditions are required to synthesise them: °C in the presence of an acid catalyst. "Tween 85" (sorbitan trioleate poly(ethylene oxide)) is one of the sorbitan ester surfactants Uses of Nonionic Surfactants The predominant use of these surfacants is in foods and drinks, pharmaceuticals and skin-care products. It is thought that these surfactants are mild on the skin even at high loadings and long-term exposure (although they can lead to a weakening of the skin barrier by helping the transport of molecules. The Key Centre for Polymer Colloids is established and supported under the Australian Research Council's Research Centres Program. To give us feedback or to obtain more information use our feedback form or contact Bob Gilbert. Copyright © Key Centre for Polymer Colloids. Last Modified: Thursday January 25, 2001 Ejemplos de alquil poliglicósidos: un alquil glucósido y un éster de glucosa.

17 Los sorbitán (polisorbatos) son comercialmente significativos.
Non ionic surfactants differ from both cationic and anionic surfactants in that the molecules are actually uncharged. The hydrophilic group is made up of some other very water soluble moeity, (e.g. a short, water-soluble polymer chain) rather than a charged species. Traditionally, nonionic surfactants have used poly(ethylene oxide) chains as the hydrophilic group. Poly(ethylene oxide) is a water soluble polymer; the polymers used in nonionic surfactants are typically 10 to 100 units long. The two common classes of surfactant that use poly(ethylene oxide) chains as their hydrophilic group are the alcohol ethoxylates and the alkylphenol ethoxylates. An alcohol ethoxylate and an alkylphenol ethoxylate. The poly(ethylene oxide) chain forms the water soluble surfactant "head". Another class of nonionic surfactants are the alkyl polyglycosides. For at least the last 20 years these have been dubbed the "new generation nonionic surfactants". In these molecules, the hydrophilic group is sugar - in this case they are just polysaccharides, but they can be made from disaccharides, trisaccharides, maltose and various other sugars. Examples of alkyl polyglycosides: an alkyl glucoside and a glucose ester. Although they are called polyglycosides, they generally only have one or two sugar groups in the chain. Sorbitan ester surfactants are commercially signicant surfactants. Fairly harsh conditions are required to synthesise them: °C in the presence of an acid catalyst. "Tween 85" (sorbitan trioleate poly(ethylene oxide)) is one of the sorbitan ester surfactants Uses of Nonionic Surfactants The predominant use of these surfacants is in foods and drinks, pharmaceuticals and skin-care products. It is thought that these surfactants are mild on the skin even at high loadings and long-term exposure (although they can lead to a weakening of the skin barrier by helping the transport of molecules. The Key Centre for Polymer Colloids is established and supported under the Australian Research Council's Research Centres Program. To give us feedback or to obtain more information use our feedback form or contact Bob Gilbert. Copyright © Key Centre for Polymer Colloids. Last Modified: Thursday January 25, 2001 "Tween 85" (polioxietileno sorbitán trioleato) es uno de ellos.

18 Usos: El uso predominante es en comidas y bebidas,
productos farmacéuticos y para cuidado de la piel. Alcohol etoxilatos and Alquilfenol etoxilatos Estos han sido ampliamente usados en formulaciones alcalinas para la limpieza de metales, limpiadores hospitalarios y reacciones de polimerización en emulsión. Debido al impacto ambiental de su uso, surfactantes tales como el nonilfenil polioxietilen éter están siendo dejados de lado. Alquil poliglucósidos Many nonionic surfactants have the problem that they become insoluble in warmer water. This temperature is known as the cloud-point - all of a sudden the solution becomes cloudy and is the surfactant begins to precipitate. This places technical restrictions on their use. Australia had a significant role in the commercial production of nonionic surfactants. The story starts with the large UK company ICI (Imperial Chemicals Industry) that had an Australian arm. In the mid-1990s, ICI Australia bought itself out and changed its name to Orica. Orica still exists today and is the world's largest explosives manufacturer; however, many of its other divisions have been sold to other companies. The surfactants division, which was one of the world's largest producers of nonionic surfactants, was sold in 1999 to Huntsman Chemicals. Huntsman Chemicals is a huge privately owned company based in the US. Alcohol Ethoxylates and Alkylphenol Ethoxylates These surfactants have been widely used in alkaline metal cleaning formulations, hospital cleaners, oil-well drilling fluids and emulsion polymerisation reactions. They have proced to be a robust and useful surfactant. However, there have been fears about the environmental impacts of their use. It appears that there are two problems with these types of surfactants, particularly the alkylphenol ethoxylates (although more recent evidence suggests these fears may be misplaced, but their reputation is already tarnished): It seems that some bacteria are able to digest the poly(ethylene oxide) chain, due to its chemical similarity to polysaccharides. The phenyl group in middle of molecule is toxic to the bacteria. There is some evidence that these surfactants may be an estrogen mimic. (Such compounds are reponsible for malformed animal genetalia and low sperm counts. As a result, surfactants such as the nonylphenyl ether poly(ethylene oxide) pictured above, are being phased out. Alkyl Polyglucosides The alkyl glucoside pictured above contains an ether linkage between the hydrophobic tale and the sugar. Although this is actually relatively easy to synthesise (you could do it in the lab), these have not proved to be cheap surfactants to produce. As a result, they are not widely used, except for a couple of niche markets and in a few dishwashing liquids. The glucose ester is industrially useful and the focus of current research. Australia's CSIRO Molecular Science has a long-running project looking at the biodegradation of these surfactants. Sorbitan Esters The sorbitan esters are a large class of surfactants. The groups that are attached to the sorbitan (the central ring structure of the molecule shown) include oleate, palmitate, stearate and ethoxylated versions of each of these (the ethoxylated oleate is shown in the structure of Tween 85 above). The ethoxylated sorbitan esters are water soluble and used as industrial emulsifiers, antistatic agents, fibre lubricants and solubilisers. The non-ethoxylated sorbitan esters are often water insoluble, but are useful as solublisers in the oil phase. These surfactants have been approved for human consumption and are widely used as emulsifiers in foods, drinks and pharamceuticals. [Source: Bartolo, R.G., Soap, in Encyclopedia of Chemical Technology, 4th ed, J.I. Kroschwitz, Editor. 1993, Wiley Interscience. p ] The Key Centre for Polymer Colloids is established and supported under the Australian Research Council's Research Centres Program. To give us feedback or to obtain more information use our feedback form or contact Bob Gilbert. Copyright © Key Centre for Polymer Colloids. Last Modified: Thursday January 25, 2001 No se ha determinado que sean de producción barata. En consecuencia no son ampliamente usados. Sorbitán ésteres Estos han sido aprobados para el consumo humano y son extensamente usados como emulsificantes en comidas, bebidas y fármacos.

19 Anfóteros o zwitteriónicos
Es un zwitterion con propiedades tensioactivas. A zwitterionic surfactant is a zwitterion that has surface-active properties. (A zwitterion is also known as an internal salt, having an anion and a cation in the one molecule chemically joined together. You may have come across zwitterions when talking about amino acids.) Zwitterionic surfactants are also called amphoteric surfactants as they often comprise a base coupled to an acid. Three zwitterionic surfactants: an ammonium carboxylate, an ammonium sulfate and an amine oxide. A couple of very simple zwitterionic surfactants are shown above. Industrially useful zwitterionic surfactants often have rings or other functional groups on them. Uses of Zwitterionic Surfactants Zwitterionic surfactants are considered to be specialty surfactants as their use is fairly limited. The 1993 US consumption of zwitterionic surfactants consisted of only 2.8% (by value) of the total surfactant trade. The one area where these surfactants have become very popular is in skin-care products. This is because they have a good "skin feel". They do not irritate the skin or eyes, and have good surfactant properties over a wide pH range. They are also said to have a favourable "safety profile", apart from not irritating the skin, they also do not assist in the transportation of other substances across the skin-barrier by solublising them. [Source: Bartolo, R.G., Soap, in Encyclopedia of Chemical Technology, 4th ed, J.I. Kroschwitz, Editor. 1993, Wiley Interscience. p ] The Key Centre for Polymer Colloids is established and supported under the Australian Research Council's Research Centres Program. To give us feedback or to obtain more information use our feedback form or contact Bob Gilbert. Copyright © Key Centre for Polymer Colloids. Last Modified: Thursday January 25, 2001 Ejemplos : un amoniocarboxilato, un amonio sulfato y un óxido de amina.

20 Usos: La única área donde estos surfactantes se han vuelto
muy populares es en productos para el cuidado de la piel. Esto es consecuencia de que tienen un buen ”tacto". No irritan la piel ni los ojos, y tienen buenas propiedades surfactantes en un amplio rango de pH..

21 Parte I: Sulfonación del dodecilbenceno
LABORATORIO Parte I: Sulfonación del dodecilbenceno oleum dodecilbenceno Ac.para dodecilbencensulfonico Reaccion de SEA Unico ej. reversible

22

23 Parte II: Sulfato de dodecilo y sodio
LABORATORIO Parte II: Sulfato de dodecilo y sodio

24 JABONES

25 Acidos Grasos Son acidos carboxilicos de cadena larga (C8 – C20)
Los Acidos Grasos saturados tienen una cadena sin dobles ligaduras ( en grasas animales, manteca) El aceite de oliva tiene acidos grasos con una sola insaturacion El aceite de soja contiene acidos grasos con dos o mas insaturaciones

26 Ácidos grasos saturados
C2 Acético Etanoico C4 Butírico Butanoico C6 Caproico Hexanoico C8 Caprílico Octanoico C10 Cáprico Decanoico C12 Láurico Dodecanoico C14 Mirístico Tetradecanoico C16 Palmítico Hexadecanoico C18 Esteárico Octadecanoico C20 Araquídico Eicosanoico C22 Behénico Docoeicosanoico C24 Lignocérico Tetraeicosanoico

27 Jabon Sal sodica de acidos grasos de cadena
Tienen una parte hidrofobica y otra hidrofilica

28 Accion limpiadora del Jabon

29 Reacción de saponificación
Los jabones se obtienen calentando grasas con NaOH conc.