Module 4: SOLUBILITY OF ORGANIC COMPOUNDS Flashcards
- a physicochemical property that refers to the ability of a given “solute” to be “dissolved” in a given amount of “solvent”
Solubility
property of solute to dissolve in a solvent
Solubility
a substance dissolved to create a solution
solute
dissolving medium
solvent
a solution that contains “less amount of solute” than the solvent
unsaturated solution
liquid mixture composed of the solute uniformly dissolved in the solvent
solution
the process of dissolvin
dissolution
a solution that contains “more amount of solute” than the solvent
supersaturated solution
a solution with the “maximum amount of solute” dissolved in the given solvent
saturated solution
certain substances exhibit “solubility property” wherein they “mix in all proportions”, forming a homogenous mixture, this property is termed as
miscibility
predicting solubility is important:
- in “purifying or isolating” a compound
- when “extracting a molecule” from its natural source
- when “designing a pharmaceutical product” which needs to be soluble enough to elicit its desired effect
- when performing “synthesis reactions” especially in the formulation of organic drugs
- the “partitioning of drug molecules” within the body between the blood and various tissues are governed by the solubility concept
predicting solubility is important:
- “purifying or isolating”
- “extracting a molecule”
- “designing a pharmaceutical product”
- “synthesis reactions”
- “partitioning of drug molecules”
the solubility is controlled by the energy balance of intermolecular forces of attraction between which molecules?
- solute-solute
- solute-solvent
- solvent-solvent
IFA means
intermolecular forces of attraction
pertains to the polarity of compounds
the rule of “like dissolves like”
Van der Waals dispersion forces
non-polar molecules
polar molecules
dipole-dipole interaction (or hydrogen bonding under certain circumstances)
dipole-dipole interaction (or hydrogen bonding under certain circumstances)
polar molecules
non-polar molecules
Van der Waals dispersion forces
depends on the “polarities of the
individual bonds” and the “shape of the molecule”
Polarity
! * evaluating these factors are quite complicated because of the “complexities of the molecules”themselves
All hydrocarbons are _____________
non-polar
Compounds with electronegative element (O and N) are generally
___________, but the degree of polarity varies from slightly polar to highly polar.
polar
The presence of __________ does not alter the polarity of the compound; therefore, these compounds are only slightly polar
halogen
Adding more “carbon” to the
chain makes the compound more
___________
non-polar
this bonding makes it possible for the solute to be dissolved in the solvent
Hydrogen bonding
- this phenomenon is also applicable to organic compounds that can exist as ions - converting the organic molecule to its salt form by ________________ (acid-base reaction)
neutralization reaction (acid-base reaction)
Solubility
= aspirin
+5% NaOH - S
+5% NaHCO3 - S
Solubility
= chloroform
conc. H2SO4 - INS
Solubility
= acetaminophen
+5% NaOH - S
+5% NaHCO3 - INS
Solubility
= n-propanol
H2O - S
pH test - 5-8 (neutral)
Solubility
= sulfadiazine
+5% NaOH - S
+5% NaHCO3 - INS
Solubility
= salicylic acid
+5% NaOH - S
+5% NaHCO3 - S
Solubility
= aniline
5% HCl - S
SOLUBILILTY CLASSIFICATION
= acetaminophen
HMW weakly acidic
SOLUBILILTY CLASSIFICATION
= aspirin
HMW strongly acidic
SOLUBILILTY CLASSIFICATION
= chloroform
HMW neutral (does not contain N or O)
SOLUBILILTY CLASSIFICATION
= n-propanol
LMW neutral
Solubility
= phenol
+5% NaOH - S
+5% NaHCO3 - INS
SOLUBILILTY CLASSIFICATION
= sulfadiazine
HMW weakly acidic
SOLUBILILTY CLASSIFICATION
= salicylic acid
HMW strongly acidic
SOLUBILILTY CLASSIFICATION
= aniline
HMW basic
SOLUBILILTY CLASSIFICATION
= phenol
HMW weakly acidic
pH > 8
LMW basic
(i.e. amines)
pH 5 – 8
LMW neutral
(i.e. contains N or O)
pH < 5
LMW acidic
(i.e. carboxylic acids)
soluble in 5% HCl
HMW basic
(i.e. amines)
soluble in 5% NaHCO3
HMW strongly acidic
(i.e. carboxylic acids)
insoluble in 5% NaHCO3
HMW weakly acidic
(i.e. phenols)
soluble in H2SO4
HMW neutral
(i.e. contains N or O)
insoluble in H2SO4
HMW neutral
(i.e. does not contain N or O)
soluble in H2O –> pH test
insoluble in H2O –>??
5% HCl test
insoluble in 5% HCl?
5% NaOH test
5% NaOH test
soluble = 5% NaHCO3
insoluble = ??
H2SO4 test
