Loss

Question 1

What causes a loss of product?

Answer 1

1. Too much solvent being added
2. Premature crystal formation during a gravity filtration
3. Crystals are filtered before recrystallization is complete

Question 2

technique used for selectively separating a compound from a mixture

Answer 2

Extraction

Question 3

method used for the separation of a mixture using two immiscible solvents
-typically used to separate organic products from a mixture after an aqueous work up or for the isolation of naturally occurring substances.

Answer 3

Liquid-liquid extraction

Question 4

What are common organic solvents used in liquid-liquid extraction?

Answer 4

petroleum ether, ethyl acetate, methylene chloride, methyl tertiary-butyl ether (MTBE), and toluene

Question 5

How to increase the solubility of organic compounds?

Answer 5

Can add acid/base.
-Strong acid protonates all bases
-week base deprotonates weak acids

Question 6

Distribution Coefficient (Kd)
solubility of solute in organic/solubility of solute in aqeuous

Answer 6

Kd>1—–>organically soluble
Kd<1—–>water soluble
Kd<10=needs multiple extractions
Kd>10=1 extraction is decent

Answer 7

Make sure the aqueous portion is at room temperature, due to many organic solvents havent low bp
-make sure to vent to prevent gas buildup

Question 8

What is salting out?

Answer 8

adding a saturated salt solution to an aqueous layer–>which decreases the solubility of the organic compound in the aqueous layer

Question 9

What are emulsions?

Answer 9

A suspension of insoluble droplets of one liquid in another liquid.
They are fixed by centrifugation and salting out.

Question 10

What is a drying agent?

Answer 10

anhydrous agents that bind to water and react by forming crystalline hydrates, which are insoluble and can be filtered out.
-sodium sulfate
-calcium chloride

Question 11

What factors should be considered when choosing a drying agent

Answer 11

capacity
efficiency
speed
inertness