Manuale di laboratorio JoVE

Basic Organic Chemistry Techniques

Basic Organic Chemistry Techniques

CONCETTI

PREPARAZIONE ISTRUTTORI

Student Protocol

Lab Manual
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Basic Organic Chemistry Techniques

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Learning Objectives

What type of glassware is used to measure the volume of liquids?

Volumetric glassware, such as graduated cylinders and volumetric pipettes, should be used to measure liquid volumes. Always used the smallest volumetric glassware possible for the volume being measured. If you are dispensing a liquid, ensure that the glassware is for dispensing the precise volume.

What advantages do round bottom flasks have over traditional Erlenmeyer flasks?

Round-bottom flasks are used to perform reactions under high heat or vacuum because the round shape is more resistant to cracking. They also provide more uniform heating or cooling than Erlenmeyer flasks.

What is the difference between vacuum and gravity filtration?

Gravity filtration uses the force of gravity to separate solids from liquids. The solution is simply poured through a funnel containing a filter paper. Vacuum filtration utilizes a vacuum to pull the liquid through the filter paper. Vacuum filtration requires using a Büchner funnel and vacuum flask setup.

Why is a Bunsen burner typically not used in the organic lab?

Bunsen burners are not used in the organic chemistry lab because most organic compounds and solvents are flammable.

What is the reflux setup and why is it used?

Reflux is used when a reaction must remain heated at a certain temperature in order to proceed. The reflux setup utilizes a condenser that turns gaseous vapor back into the liquid phase, which prevents the loss of solvent due to evaporation.

List of Materials

Lab stand

10
2-prong clamp

15
50-mL beaker

15
100-mL beaker

10
250-mL beaker

5
400-mL beaker

5
600-mL beaker

5
10-mL graduated cylinder

15
50-mL graduated cylinder

5
25-mL Erlenmeyer flask

5
250-mL filter flask

5
20-mL test tube

5
Glass stirring rod

5
10-cm Büchner funnel with rubber filter adapter

5
Thermometer (acid-resistant)

5
Pipette bulbs

10
Lab tape

5 rolls
Marker or pen

5
18.4 M Sulfuric acid (98 wt%)

100 mL
15.7 M Nitric acid (68-70 wt%)

100 mL
Methyl benzoate

20 mL
Ice machine or crushed ice

5 L
Deionized water

250 mL
Weighing boats

5
20-mL glass bottle with acid-resistant cap

10
Pasteur pipettes

-1 Dependent on lab size
Circular filter papers

5
Laboratory wipes

-1 Dependent on lab size
Top-loading balance (at least 1)

-1 Dependent on lab size
Spatula

3
10-mL graduated cylinder

2
Glass funnel

2
Sodium bicarbonate

500 g

Lab Prep

Source: Lara Al Hariri at the University of Massachusetts Amherst, MA, USA

Preparation of the Laboratory

Here, we show the laboratory preparation for 10 students working in pairs, with some excess. Please adjust quantities as needed.

To set up for this lab experiment, wear the appropriate personal protective equipment, including a lab coat, chemical splash goggles, and gloves.
Ensure that there are labeled waste containers for non-halogenated organic waste, hydrochloric acid waste, aqueous waste, and glass waste.
Place a container of sodium benzoate and a small waste container for excess sodium benzoate by the balances.
Ensure that the balances have enough weighing boats, spatulas, and lab wipes for the class.
In a fume hood, place 150 mL of tetrahydrofuran in a 250-mL glass bottle. Cap the bottle and label it ‘tetrahydrofuran’.
Carefully place 35 mL of 3 M hydrochloric acid in three 50-mL glass bottles. Cap the bottles and label them with the solution's name and concentration.
Place these bottles of THF and HCl in a central hood and put away the stock bottles.

Set out the following glassware and equipment at each student lab station (we suggest that students work in pairs):

2 Lab stands

1 Stirring hotplate

1 Lab jack

1 Small thermometer clamp

3 Medium 3-prong clamp

1 Condenser

2 Rubber tubing

2 Vacuum tubing

3 50-mL beaker

2 250-mL beaker

1 600-mL beaker

1 5-mL graduated cylinder

1 10-mL graduated cylinder

1 50-mL graduated cylinder

1 250-mL filter flask

1 50-mL round-bottom flask with cork holder

1 Büchner funnel with rubber adaptor

2 Pasteur pipette bulbs

1 Stir bar

1 Glass stirring rod

1 Roll of lab tape with pen

1 Thermometer

Fill plastic wash bottles with deionized water and distribute them around the lab. Set out a tube of vacuum grease and boxes of circular filter papers, laboratory wipes, and Pasteur pipettes in a central location.

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JoVE Lab Chem Lab: 50 Prep