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organic derivatives and their properties
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EXERCISE 7:
EXERCISE 7:Organic Derivatives of Water
oxygen containing compounds in addition to carbon and hydrogen
arise from the replacement of one or both of the hydrogen atoms of water by an organic group Organic Derivatives of Water
Alcoholone hydrogen atom is replaced by an alkyl group
Functional group is a hydroxyl group
can be classified as a primary, secondary or tertiary depending on the number of carbon substituents bonded to the hydroxyl bearing carbonOrganic Derivatives of Water
Phenolone hydrogen atom is replaced by an aryl group
hydroxyl group is directly bonded to an aromatic systemOrganic Derivatives of Water
Etherboth hydrogen atoms are replaced by an alkyl or aryl groups
relative inert molecules since the C-O-C bond is quite stable and can be cleaved only under drastic conditionsOrganic Derivatives of Water
SampleH2ONaOHH2SO41-butanol--+2-butanol+/--+tert-butanol+-+phenol-++diethyl ether--+
SOLUBILITY TESTS
Solubility in waterimmiscibility of 1-butanol, phenol and diethyl ether in water is explained by the size of the hydrophobic portions of the molecules as compared to their hydrophilic partssize of the hydrophobic parts in each molecule is so great compared to the hydrophilic portion, rendering each molecule as water-insoluble.SOLUBILITY TESTS
Solubility in waterEffect of branchingas degree of branching increases, the molecule becomes more spherical in shape. The increase in spherical shape reduces the surface area of each molecule which reduces the intermolecular forces of the alcohol molecules. This makes it easier for water to solvate the molecules. SOLUBILITY TESTS
tgh8
Solubility in NaOHboth alcohols and phenols under certain conditions can act as Lewis acids due to the proton present in the moleculethe solubility test in NaOH clearly shows that phenols are stronger Lewis acids than alcoholsthe difference in acidities can be explained by the relative stabilities of the conjugate basesSOLUBILITY TESTS
Solubility in NaOHThe negative charge on the O atom of the butoxide is intensified by the electron releasing alkyl group and is therefore destabilizedMost alkoxides are strong bases and will easily attract protons to form back the alcoholsFor phenol, it forms upon losing a proton the resonance-stabilized phenoxide ionBecause of the resonance forms of the phenoxide, phenol has a greater tendency to lose a proton to form the more stable phenoxide ion. Phenol is thus a stronger acid than butanolSOLUBILITY TESTS
Solubility in H2SO4Most organic derivatives of water are soluble in sulfuric acid
Used to indicate the presence of oxygen atoms in a moleculeSOLUBILITY TESTS
Reagent: hot acidic KMnO4Positive result: loss of purple color and formation of brown precipitateused to detect presence of primary and secondary alcohols and phenolsPotassium Permanganate Test
SampleResultSample Result1-butanol+tert-butanol-2-butanol+phenol+diethyl ether-
Potassium Permanganate Test
Potassium Permanganate Test
KMnO4MnO2(s)MnO2(s)
Potassium Permanganate Test
KMnO4MnO2(s)
KMnO4MnO2(s)
Reagent: HCl-ZnCl2Positive result: appearance of cloudiness due to alkyl chloride formedused to detect presence of secondary and tertiary alcohols
Lucas Test
Lucas Test
HCl/ZnCl2H2O
HCl/ZnCl2H2O
Reagent: FeCl3Positive result: formation of a colored (usually red or purple) complexdetect presence of phenolsFerric Chloride Test
SampleResult1-butanol-phenol+
Ferric Chloride Test
FeCl3Fe3+33Cl-3H+
Reagent: I2/KIPositive result: formation of yellow precipitatedetect presence of methyl alcoholsIodoform Test
SampleResult1-butanol-2-butanol+
Iodoform Test
I2/OH-
Reagent: Ag(NH3)2+Positive result: formation of silver mirrordetect presence of phenols
Tollens Test
SampleResult1-butanol-2-butanol-phenol+
Tollens Test
Ag(NH3)2+Ag0
SampleHot acidic KMnO4Lucas TestFeCl3 testTollens TestPrimary ROH+---Secondary ROH++--Tertiary ROH-+--Ar-OH+NA++R-O-R-NA--
Generalization