copyright © 2010 pearson education, inc. quimica organica jabones/tensioactivos/detergen tes/soap
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Copyright © 2010 Pearson Education, Inc.
Quimica Organica
Jabones/tensioactivos/detergentes/soap
Copyright © 2010 Pearson Education, Inc.
Recordemos Acidos carboxilicos
Estructura de Lewis del acido formico
O
CH O
H
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Propiedades fisicas de acidos carboxilicos
Acidos carboxilicos son polares:
O
CO
HCH3
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Carboxylic acids pueden formar puentes hidrogeno:
CH3 C
O
O
H
CH3C
O
OH
Propiedades fisicas de acidos carboxilicos
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Propiedades físicas de los ácidos carboxilicos
• Carboxylic acids also interact with water molecules by hydrogen bonding through both the carboxyl oxygen and the hydroxyl group.
H OH HO
H
HOH
H
OH
O
CCH3 O
H
H
H
O
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Preparation of Carboxylic Acids
Oxidation of Primary Alcohols
CH3(CH2)5CH2OHH2CrO4 CH3(CH2)5COH
O
HOCH2CH2CH2CH2OH HOCCH2CH2COH
O OKMnO4
1-heptanol heptanoic acid
1,4-butanediol butanedioic acid
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Reactions of Carboxylic Acids
Acidity• Los acidos carboxilicos son levemente
ionizados en soluciones acuosas y por tanto clasificados como acidos debiles (weak acids)
CH3CO2H CH3CO2 + HH2O
[H ] [CH3CO2 ] [CH3CO2H]Ka = = 1.8 x 10-5
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Acidity of Carboxylic AcidsAll carboxylic acids, whether soluble or
insoluble in water, react quantitatively with NaOH, KOH, and other strong bases to form salts
CO2H CO2 Na
+ H2O + NaOH
benzoic acidlevemente soluble en agua(only slightly soluble in H2O)
sodium benzoate soluble en agua(very soluble in water)
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Acidity of Carboxylic AcidsCarboxylic acids also react with weaker
bases such as sodium bicarbonate to form salts
CO2 K
CH OH
CHO H
CO2H
CO2 K
CH OH
CHO H
CO2 Na
+ NaHCO3 + CO2 + H2O
potassium hydrogen tartrate (cream of tartar)
sodium bicarbonate (baking soda)
Acidity of Carboxylic AcidsCarboxylic acids solo reaccionan con bases
debiles como el bicarbonato de sodio para formar sales
CO2 K
CH OH
CHO H
CO2H
CO2 K
CH OH
CHO H
CO2 Na
+ NaHCO3 + CO2 + H2O
potassium hydrogen tartrate (cream of tartar)
sodium bicarbonate (baking soda)
Baking powder: una mezcla de bicarbonato de sodio con tartrato acido de potasio. Cuando se añade agua, la parte acida de la sal del tartrato reacciona , y se libera dioxido de carbono.
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Acidity of Carboxylic Acids• Otro ejemplo: cuando se mezcla
bicarbonato de sodio con suero de leche, el cual contiene ácido lactico:
OH
CH3CHCO2H
OH
CH3CHCO2 Na
+ NaHCO3
+ CO2 + H2O
2-hydroxypropanoic acid (lactic acid)
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Derivatives of Carboxylic Acids
O
CR O
C
O
R
O
CR O
R
O
CR N
R
R
O
CR Cl
an acid chloride an anhydride
an ester an amide
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NomenclatureEsters
• El grupo alquil o aril unido al oxigeno es el que se nombra segundo para los españoles (The alkyl or aryl group attached to the oxygen is named first).
O
CCH3 O
CH2CH3
Alkyl Group: Carboxylic Acid: Name of Ester:
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NomenclatureEsters
• The alkyl or aryl group attached to the oxygen is named first.
O
CCH3 O
CH2CH3
Alkyl Group: ethyl Carboxylic Acid: acetic acid Name of Ester: ethyl acetate
EtiloAcido acéticoAcetato de etilo
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Nomenclature
• Another ester
Alkyl Group: isopropyl Carboxylic Acid: benzoic acid Name of Ester: isopropyl benzoate
O
CO
CH
CH3
CH3
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Nomenclature
• Another ester
Alkyl Group: isopropyl Carboxylic Acid: benzoic acid Name of Ester: isopropyl benzoate
O
CO
CH
CH3
CH3
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Nomenclature
• Another ester
Alkyl Group: isopropyl Carboxylic Acid: benzoic acid Name of Ester: isopropyl benzoate
O
CO
CH
CH3
CH3
isopropilÁcido benzoicoBenzoato de isopropilo
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Practice Problems
Name the following esters:
O
CCH2 O
CH3CH
CH3
CH3
O
CO
CHH
CH3
CH2CH3
methyl 3-methylbutanoate(methyl isovalerate)
sec-butyl formate
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Physical Properties of EstersEsters are polar compounds. Most esters are insoluble in water. Esters are soluble in polar organic solvents
such as diethyl ether and acetone.
Methyl acetate
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Reacciones de esteres
Hidrolisis• Los Esteres son normalmente no-reactivos con
agua. • Sin embargo, en presencia de acidos (aq. HCl
or H2SO4) o bases (NaOH or KOH), pueden
hidrolizarse
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Hidrólisis Catalizada por ácidos
El reverso de la esterificación de Fischer:
O
CCH3 O
CH2CH3
O
CCH3 OH
+ H2O
+ HOCH2CH3
H
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Base-Promoted Hidrolisis promovida por bases
Esta reacció es usada para la obtencion de jabones
O
CCH3 O
CH2CH3
O
CCH3 O Na
+ NaOH
+ HOCH2CH3
H2O
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Mechanism of Saponification
Step One – Nucleophilic addition of hydroxide anion:
O
CCH3 O
CH2CH3
OHO
CCH3 OCH2CH3OH
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Mechanism of Saponification
Step One – Nucleophilic addition of hydroxide anion:
O
CCH3 O
CH2CH3
OHO
CCH3 OCH2CH3OH
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Mechanism of Saponification
Step Two – Elimination of alkoxide anion:
O
CCH3 OCH2CH3OH
O
CCH3 O
H + OCH2CH3
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Mechanism of Saponification
Step Two – Elimination of alkoxide anion:
O
CCH3 OCH2CH3OH
O
CCH3 O
H + OCH2CH3
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Mechanism of Saponification
Step Three – Proton reorganization (acid–base reaction):
O
CCH3 O
+ HOCH2CH3
O
CCH3 O
H + OCH2CH3
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Mechanism of Saponification
Step Three – Proton reorganization (acid–base reaction):
O
CCH3 O
+ HOCH2CH3
O
CCH3 O
H + OCH2CH3
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Ejemplo Problema
Complete the following reaction:
O
CCH3 O
hydrolysis inaqueous acid
H3OO
CCH3 OH
HO+
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Complete the following reaction:
O
CCH3 O
hydrolysis inaqueous acid
H3OO
CCH3 OH
HO+
Ejemplo Problema
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Sample Problem
Complete the following reaction:
OC
O
CH3CH2
O
CCH3 O
CH2saponification in aqueous NaOH
O
CCH3 O Na
NaOH H2O
2 + HOCH2CH2OH
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Sample Problem
Complete the following reaction:
OC
O
CH3CH2
O
CCH3 O
CH2saponification in aqueous NaOH
O
CCH3 O Na
NaOH H2O
2 + HOCH2CH2OH
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Sample Problem
Complete the following reaction:
OC
O
CH3CH2
O
CCH3 O
CH2saponification in aqueous NaOH
O
CCH3 O Na
NaOH H2O
2 + HOCH2CH2OH
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Soaps/ Jabones• Sodium stearate/ estereato de Na:
ionic(hydrophilic)
hydrocarbon(hydrophobic)
Soaps/ Jabones a partir de grasa
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Soap• A soap micelle:
Na
CO2
CO2
CO2
CO2
CO2O2C
O2C
O2C
O2C
O2C
O2C
CO2
O2C CO2
O2C
Na
Na
Na Na
Na
Na
Na
Na
Na
Na
Na
Na
Na
Na
Na
H2OH2O
H2O
H2OH2O
H2O H2O
H2O
Hidrofilica
Hidrofobica
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Soap• A soap micelle:
Na
CO2
CO2
CO2
CO2
CO2O2C
O2C
O2C
O2C
O2C
O2C
CO2
O2C CO2
O2C
Na
Na
Na Na
Na
Na
Na
Na
Na
Na
Na
Na
Na
Na
Na
H2OH2O
H2O
H2OH2O
H2O H2O
H2O
Mancha grasa
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LAS
Algunas propiedades de los tensioactivos son:
Clasificación de los detergentes (tensioactivos):
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Ejemplo de formacion de un detergente anionico
H2SO4
cold
NaOH
OH
OSO3H
OS
O
OO Na
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H2SO4
cold
NaOH
OH
OSO3H
OS
O
OO Na
hydrophilichydrophobic
Sodium dodecyl sulfate
Ejemplo de formacion de un detergente anionico
Detergentes anionicos• Alkyl benzene sulfonate detergents (ABS)
– Non-biodegradable
hydrophilichydrophobic S
O
OO Na
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Copyright © 2010 Pearson Education, Inc.
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