Pharmaceutical Organic Chemistry [EXP 3] Separation and Purification of Organic Compounds

Crystallization

Highly effective method of purifying an organic substance, provided that the physical properties of a given compound permit its ourification in this manner.

Crystallization

Involves the process of dissolving the materials to form a saturated solution in a suitable solvent at an elevated temp.

Filtering; remove; insoluble; crystallization

___________- while hot will __________________ any suspended _____________ particles, and letting _______________ proceed

1. Dissolves the solute readily at an elevated temp, sparingly in a lower temperature
2. No chemical reaction with the solute
3. Sufficiently volatile so that it may be removed from the purified crystals

Desirable Solvent for Crystallization

readily; elevated; sparingly; lower

Dissolves the solute __________ at an ____________ temp, ______________ in a ________ temperature

No chemical reaction with the solute

A desirable solven gives a chemical reaction with the solute. (T or F)

Sufficiently volatile

It mus be ___________ _____________ so that it may be removed from the purified crystals

1) removal of impurities
2) nucleus formation
3) encouragement of growth of crystal to visible form.

3 stages of crystallization

Removal of Colored Impurities

It is done by adding the decolorizing carbon (Animal Charcoal)

Nucleus formation

may be spontaneous or indirect

Seeding

When Organic Substances do not crystalize readily, even in saturated solutions, this technique is done by adding a small crystal of pure materials to induce the process of crystallization.

-Seeding
-Scratching

2 Mentioned ways to induce Crystallization

Crystallization; scratching the sides

_______________ can be induce by ________ ___ _______ in the glass surface provide sharp edges upon crystal growth.

Sublimation

It is the direct conversion of solid to gas without undergoing the liquid phase

Sublimation

It can be applies when the components of a solid mixture differ appreciably in their vapor pressure

Sublimation

Involves gentle heating of the mixture in a confined container, until particles of a solid escape into vapor phase.

Vapos; cold; crystals;high vapor pressure; collected; lower; left

When the _______ are condensed on the ____ surface, _________ of the component with _____ ______ ____________ can be __________ with the component of _________ vapor pressure _________ in the contianer

purification; volatility; vaporized

Sublimation as a process of ____________, it also depend on differences in ___________, that is in this case with which substance can be ___________.

Less volatile or non-volatile impurities

These impurities will remain behind as a residue after purified solid has been collected.

Limited; similar

Sublimation is convenient to apply and require less time, its applicability is _________. It cannot be used for separation of compounds with ________ vapor pressures.

Extraction

This is rhe method of withdrawing or separating from a mixture by use of a solvent

Extraction

When applying this method, the mixture is dissolved in one of two miscible solvents then shaken with the other to distribute the components between them.

Directly proportional

Relationship of amounts of components in each of the two solvents and their solubility

Water

one of the solvents used in the extraction process.

Diethyl ether

One of the most important organic solvents, used extensively as an extracting solvent.

Diethyl ether

Has high solvent power for hydrocarbons and for oxygen-conatining compounds, it is also highly volatile that it is easily removed from an extract at low temperature that evn a sensitive compound is not liable to decompose.

Diethyl ether

often preferred to be used for research because of fire hazard, losses in solvent recovery incident to its volatility, and oxidation to peroxide on long exposure to air, which represents the hazard of able to explode.

Ethyl

Slightly soluble in water. Its efficiency can be improved considerably by the addition of a small amoint of ionize salt, s/a NaCl to the water layer.

Increase; decrease

An ____________ in polar property of the water solution will cause a ___________ in solubility of the non-polar compoun. (inversely proportional)

Slating-out effect

The reduced solubility of the organic compounds in the water in the presence of electrolyte

Extraction with water

process where immiscible solvent is useful for isolation of natural products that occur in animal and plant tissues having high water count.

True

Crystallization can be induced by scratching the sides in the glass surface (True or False)

Turbid red sol'n with some undissolved benzoic acid

Benzoic Acid + NaCl + Congo Red + Distilled Water's appearance before heating

BaCl2

What was added to test for the purity of the Naphthalene in the sublimation set-up?

AgNO3

What was the added to test the purity of Benzoic acid in the crystallization set-up

AgCl

Identity of the impurity of the crystallization of Benzoic acid in case the solution turns turbid

Ba2SO4

Identity of the impurity of the sublimation of Naphthalene in case the solution turns turbid

Intense red color

What color is the gumamela extract after addition of acid?

Green

After the addition of a base what color did the gumamela extract turn to?

Chlorophyll

Identity of the extract in pechay leaves

Naphthalene

The organic compound that was used in the sublimation set-up

Activated Charcoal

This was added to decolorize the carbon in the crystallization bensoic acid

bigger crystals of benzoic acid

Rapid cooling of the filtrate from the crystallization set-up will result to what size of crystals?

smaller crystals of benzoic acid

slow cooling of the filtrate from the crystallization set-up will result to what size of crystals?

95% Ethanol

Solvent used to extract gumamela

Methanol

Solvent used to extract chlorophyll from pechay