carboxylic acids unit 6. general formula rcooh and arcooh functional group = o c -oh
TRANSCRIPT
Common Names…1C – Formic Acid (Methanoic Acid)
From Formaldehyde (methanal)
2C – Acetic Acid (Ethanoic Acid)From Acetaldehyde (ethanal)
3C – Propanoic Acid (Propanoic Acid)From Propanaldehyde (propanal)
4C – Butyric Acid (Butanoic Acid)
From Butyraldehyde (butanal)
Uses – Just FUN Facts – Not Tested!
Formic Acid – First Isolated from AntsUsed in dyeing and finishing textiles and many
other uses!
Acetic Acid – Naturally produced by usAka vinegar – many uses
Propanoic Acid – in Greek, means “first fat”Grain Preservative and antifungal
Butyric Acid – Naturally occurring – Greek for butterSmells like vomit
Preparation of Carboxylic Acids – You already know this
Oxidation of aldehydes
O KMnO4 O
R-C-H R-C-OH
RCHO KMnO4 RCO2H
Reactions of Carboxylic Acids
1.Halogenation: RCO2H + X2 RXCO2H + HX
ArCO2H + X2 FeX3 ArXCO2H + HX
Form 2,3,4 – trichloroheptanoic acid (str,cond)
O Cl Cl Cl O
C-C-C-C-C-C-C-OH + 3Cl2 C-C-C-C-C-C-C-OH
+3HClCH3(CH2)5CO2H + 3Cl2CH3(CH2)2(CHCl)3CO2H + 3HCl
Reactions of Carboxylic Acids
2. Nitration of benzanoic acid
ArCO2 + HNO3 H2SO4 ArNO2CO2H + H2O
Form metanitrobenzanoic acid (str,cond)
Reactions of Carboxylic Acids
Acid Salt formation can be done 2 ways…
1.RCO2H + M° ArNO2CO2H + H2O
Metal can be same 7 as before
Examples
React ethanoic acid with sodium (str,name,cond)
O O
2C-C-OH + 2Na2(C-C-O-)Na+ + H2
2CH3CO2H+2Na2(CH3CO2-)Na+ +H2
Sodium ethanoate
Examples
To name acid salts:
1.Name Metal ion
2.Drop –ic acid and add –ate
Ex: React butyric acid with magnesium (str,cond,name)
Acid Salt Formation – 2nd Way!
2. Carboxylic acid + metal hydroxide acid salt + water
RCO2H + MOH(RCO2-)M+ + H2O
React butanoic acid with magnesium hydroxide (str,cond, name prod)
Other Reactions of Carboxylic Acids
Convert carboxylic acids to “functional derivatives”
Functional Derivative – an organic compound containing the acyl group O
Acyl group = RCO = R-C-
Conversion to acid chlorides
O O
4. R-C-OH + SOCl2 R-C-Cl + SO2 + HCl
RCO2H + SOCl2 RCOCl + SO2 + HCl
Carboxylic acid + thionyl chloride acid chloride + sulfur dioxide + hydrogen chloride
Examples
React hexanoixc acid with thionyl chloride (s,c,np) O O
C-C-C-C-C-C-OH + SOCl2C-C-C-C-C-C-Cl + SO2+HCl
CH3(CH2)4CO2H + SOCl2 CH3(CH2)4COCl + SO2+HCl
To name acid chlorides:
1.Drop –ic acid
2.Add –yl chloride
Conversion to amides
5. Converting carbox. Acids to amides
O H O H
R-C-OH + H-N-H R-C-N-H + H2O
Carboxylic acid + ammonia amide + water
Example
Rct pentanoic acid w/ammonia (s,c,np) O H O H
C-C-C-C-C-OH + H-N-H C-C-C-C-C-N-H + H2O
CH3(CH2)3COH + NH3 CH3(CH2)3CONH2 + H2O
To Name Amides: pentanimide
1. Drop –e from corresponding alkane
2. Add –amide
Conversions to Esters
Fischer Esterification
O OR-C-OH + R’-OH H2SO4 R-C-O-R’ + H2O
RCO2H + R’OH H2SO4 RCO2R’ + H2O
Carboxylic acid + alcoholester + water
Example
React propanoic acid with butanol (s,c,np) O O
C-C-C-OH + C-C-C-C-OH H2SO4 C-C-C-O-C-C-C-C + H2O
CH3CH2CO2H + CH3(CH2)2CH2OH H2SO4 CH3CH2CO2(CH2)3CH3+ H2O
butyl propanoate