Org Deriv of Water (Alcohol & Phenol) Flashcards
(32 cards)
ORGANIC DERIVATIVES OF WATER
- replacement of (how many?) hydrogen atoms of ____ with an _____ _____
- 4 types
- one or more H atoms
- water / H2O
- organic group
- Alcohols (ROH)
- Phenol (ArOH)
- Ether (ROR)
- Epoxide (Cy ROR)
ROH
- compounds that have _____ groups bonded to a ____ ____ hybridized carbon atom
- 3 classifications?
- hydroxyl group (-OH)
- saturated sp3 hybridized carbon
- Primary
- OH attached to primary C - Secondary
- OH attached to secondary C - Tertiary
- OH attached to tertiary C
ROH - NOMENCLATURE
- rules for the ff:
- common name
- IUPAC
- cyclic alcohols
- enol / ynol
- alkyl name (remove “e”) + -ol
(methanol ; propanol) - longest carbon chain passing thru all α-carbon containing OH = parent name
- numbering begins from end closest to OH group
(2-propanol ; 2-methyl-2-propanol) - ring bearing OH grp = parent name
- position 1 automatic given to OH
- if only 1 OH grp: cyclohexanol
- if 2 or more: cyclohexane-1,2-diol or cyclohexane-1,2,4-triol - ) PRIORITY OH GROUP
ENOL: alkene (remove “e”) + position number of OH grp + -ol
[e.g. 2-propen-1-ol]
YNOL: alkyne (remove “e”) + position number of OH grp + -ol
[e.g. 2-methyl-3-pentyn-1-ol]
ROH - PHYSICAL PROPERTIES
Solubility
- soluble in __ + reason
- determine if solubility in ^^ will increase or decrease if:
1. increase chain length
2. increase branching
- soluble in water due to ability to form H-bonds in the pure state and with water
- decrease solubility in water (due to increase in size of nonpolar region
- increase solubility in water
ROH - PHYSICAL PROPERTIES
Boiling Point
- determine if BP will increase or decrease if:
1. increase chain length
2. increase branching - arrange the ff in DECREASING ORDER in terms of BP:
a. BP alcohols
b. BP alkanes
c. BP halides
- increase BP
- decrease BP
BP alcohols > BP halides > BP alkanes
- if compounds have comparable MW
ROH - PHYSICAL PROPERTIES
Acidity
- arrange the ff in DECREASING ORDER in terms of acidity:
a. water
b. phenol
c. alcohols
phenol > water > alcohols
ROH - PHYSICAL PROPERTIES
Stability
- arrange the ff in DECREASING ORDER in terms of stability:
a. phenoxide ion (-OAr ion)
b. alkoxide ion (-OR ion)
c. hydroxide ion (-OH ion)
+ reason
phenoxide ion* > hydroxide ion > alkoxide ion**
*resonance stabilized since charge is spread over ring
**intensified (-) charge via inductive effect
ROH - PREPARATION
4 ways to prepare alcohols
- fermentation of sugar
- hydration and hydroxylation of alkenes
- halohydrin formation
- rxn of alkyl halides w water or metal hydroxides
what organic compound is the center of all organic compounds?
alcohol
ROH - REACTIONS
- 2 main reactions + 2 subtypes for each
- Cleavage of O-H bond
a. formation of alkoxides
b. oxidation of alcohols - Cleavage of C-O bond
a. conversion of alcohols to alkyl halides
b. acid-catalyzed dehydration of alcohols
ROH - RXNS - CLEAVAGE OF OH
Formation of Alkoxides
- reagents (4)?
- chemical reaction?
- order of reactivity? + reason?
- active metals (Na, K, Li, Mg, or Al)
- NaH
- NaNH2
- Grignard Reagents (RMgX)
ROH + Metal -> RO-M+ + H2(g)
CH3OH > 1° > 2° > 3°
- alkoxide becomes LESS STABLE w/ more R groups on α-carbon
ROH - RXNS - CLEAVAGE OF OH
Formation of Alkoxides
- when will a NO REACTION occur? + reason
- if NaOH is used as reagent
ROH + NaOH -> RO-Na+ + H2O
*H2O is more acidic so backward reaction takes place
ROH - RXNS - CLEAVAGE OF OH
Oxidation of Alcohols
- common oxidizing reagents (4)
- milder oxidizing reagent (1)
- determine the products of the ff classifications of OH:
- 1°
- 2°
- 3°
- COMMON
1. Hot / Hot Acidic KMnO4
2. H2CrO4 (chromic acid)
3. K2Cr2O7, H+
4. Jones reagent: CrO3, H2SO4, acetone) - MILDER
- PCC (pyridinium chlorochromate) in CH2Cl2
1° : Carboxylic Acid (common)
: Aldehyde (mild)
**turns C atom into double bond O + retains OH or turns OH into H
2° : Ketone (common & mild)
**turns OH atom into double bond O
3° : N.R.
ROH
- test for classifying 2 classifications of alcohols
- distinguishes WHAT?
- reagent (3)?
- positive result?
JONES TEST
- distinguishes 1° & 2°
- CrO3
- H2SO4
- Acetone
- production of a green to blue opaque suspension within 2 seconds
ROH - RXNS - CLEAVAGE OF CO
Conversion of Alcohols to Alkyl Halides
- reagents (4)?
- mechanism followed?
- order of reactivity?
- prefers classification of OH
REAGENT: HBr / HCl
- SN1 mechanism
- 3° > 2° > 1°
- prefers 3° OH, then 2° OH only
REAGENT: PBr3 / SOCl2
- SN2 mechanism
- 3° < 2° < 1°
- prefers 1° OH, then 2° OH only
ROH - RXNS - CLEAVAGE OF CO
Acid-Catalyzed Dehydration of Alcohols
- mechanism followed?
- order of reactivity?
- reagents (3)?
- products (2)?
- follows what rule?
- E1 mechanism
- 3° ROH > 2° ROH > 1° ROH
1.) H3PO4 -> heat
2.) H2SO4 -> heat
3.) H3O+
a.) major product - more substituted alkene
+
b.) H2O
- Zaitsev’s Rule - major product is more substituted alkene
ROH
- test for classifying ALL alcohols
- reagents (2)?
- positive result? + result for each classification
Lucas Test
- conc. HCl
- ZnCl2
- formation of an insoluble layer of alkyl
3° : fast reaction (w KMnO4 oxidation)
2° : reaction after several minutes (w KMnO4 oxidation)
1° : only upon heating
ArOH
- general structure?
-OH group attached to aromatic ring
ArOH - NOMENCLATURE
- rules (2)?
- same rules as aromatic compounds
- parent name = phenol
ArOH - PHYSICAL PROPERTIES
type of bond formation?
Hydrogen Bond Formation
- possible in pure samples or with water
ArOH - PHYSICAL PROPERTIES
Solubility
insoluble / slightly soluble in H2O due to large non-polar benzene
ArOH - PHYSICAL PROPERTIES
Boiling Point
phenols have HIGHER BP than alkylbenzenes & alkanes
ArOH - PHYSICAL PROPERTIES
Acidity (2)
- dissociates where?
- forms what?
PHENOLS:
- dissociates slightly in aq. solutions
- form resonance-stabilized phenoxide ions
- dissociates slightly in aq. solutions
- form alkoxide ions (not as stable as phenoxide ions)
ArOH - PHYSICAL PROPERTIES
Acidity of MONOSUBSTITUTED PHENOLS
- 2 groups that affect acidity?
-> disperses / intensifies (-) charge?
-> stability of phenoxide ions?
-> effect on acidity of phenol?
- Electron-withdrawing Groups
- disperses (-) charge
- phenoxide ion is more stable + forms easily
- enhances acidity of phenol - Electron-releasing Groups
- intensifies (-) charge
- phenoxide ion is destabilized & hardly formed
- reduces acidity of phenol
