Fall Organic Chemistry Experiment #1
Introduction to the Organic Chemistry Lab
Suggested Reading:
"The Student's Lab Companion: Laboratory Techniques for Organic Chemistry”, by John W. Lehman
Introduction
p. 11-18 Laboratory Safety,
p. 19-26 Finding and Using Chemical Safety Information
p. 35-54: OP-1 (Cleaning and Drying Glassware) OP-2 (Using Specialized Glassware) OP-3 (Using Glass Rods and Tubing) OP-4 (Weighing) OP-5 (Measuring Volume) OP-6 (Making Transfers)
Appendices I-V
Procedure:
You should record all laboratory procedures as well as observations and calculations in your laboratory notebook!
Pre-laboratory work
(1) In order to prepare for work in the organic chemistry laboratory, you must properly label each day’s laboratory activity. There is no substitute for a well-organized, complete record of your experiments. The following directives will give you a head start:
a. Give this experiment a title and record today’s date
b. Write out the purpose/hypothesis of today’s experiment
c. Write out (using structures) the reaction between acetic acid and ethanol using hydrochloric acid (as a catalyst) to yield ethyl acetate and water.
d. If we start with 25 mL of acetic acid and 20 g of ethanol, and we receive 1.5 g of ethyl acetate at the end of the reaction, write out the calculation that shows the % yield of ethyl acetate.
(2) Preparing the Physical Properties Appendix.
Some guidelines: For each laboratory experiment that you perform this year, we expect that you will enter all of the pertinent physical property (MW, density, bp, mp, flash point, solubility) and safety information (NFPA coding, primary health hazards, PPE, accident procedures, etc) for reagents used. Information can be most easily obtained by looking at the Material Safety Data Sheet (MSDS) which can be found either via a web-based repository (several sites are linked to http://www.ilpi.com/msds/) or through our in-house El Cid Inventory Tracking program. In addition, you can also find information on physical data in the Aldrich chemical catalog (copies are available in S303). Once the information for a particular reagent has been entered into your notebook, you will not need to enter it again. This saves considerable time and this is why we want you to keep this running record of reagent information toward the back of your laboratory notebook (in a labeled Appendix section).
a. Acetone – find its boiling point, flash point, and synonyms according to information from a filed MSDS in S303 – according to its flashpoint and boiling point, is acetone considered a highly flammable (Class 1A) material?
b. Methylene chloride – find all health effects, first-aid measures, and fire-fighting measures for this compound listed in an on-line MSDS resource
c. Diethyl ether – find all synonyms, exposure limits, and personal protective equipment for this compound from an on-line MSDS resource – according to its PEL or TLV values, can we use diethyl ether out on the bench top or should we use it in a fume hood?
d. Hexanes – find health effects and first-aid measures pertaining to this compound
e. Chloroform – find its density
f. Benzoic acid – find solubility data for this compound in various solvents by looking in the Merck Index (available in the Science Center, S303).
g. Toluene – find NFPA safety data ratings (health, flammability, reactivity, and special precautions), handling, storage, and stability/reactivity information for this compound
(3) Go to the following web address and watch Video #11 (Using a Balance)
http://ocw.mit.edu/ans7870/resources/chemvideo/index.htm
Work completed during lab
(1) Operations (compounds listed in BOLD should be entered into your physical properties and safety appendix)
a. Learn how to operate the fume hood.
b. Walk through the laboratory and locate where glassware and equipment is routinely stored. It may be helpful to use the glassware/equipment inventory sheet posted on the organic website.
c. Locate the items in Figure A2 (page 40 in the Lehman text) from the lab drawers and assemble them according to the diagram. Show to your instructor for evaluation. Prepare a sketch of the glassware setup and enter it into your laboratory notebook.
d. Using appropriate glassware and volumetric devices, measure out the following volumes of water and then transfer according to the directive shown.
1. 110 mL of water to a 250 mL Erlenmeyer flask
2. 10 mL of acetone to a 25 mL round-bottom flask. Clamp the to a ring stand and set up for reflux. Take the RBF and remove the solvent using the rotary evaporator.
3. 4 mL of dry THF to a 100 mL 2-neck round-bottom flask under an inert nitrogen (gas) atmosphere. Set up for cooling via an ice bath. Once cooled, transfer via pipette to a 50 or 100 mL beaker.
e. Weigh out 225 mg of acetanilide and transfer to a properly labeled vial. Cap the vial and place in the drawer assigned to your lab section for storage.
f. Properly wash some glassware and put it away. Samples can be obtained from your instructor.
(2) Clean-up (YOU ARE REQUIRED TO FOLLOW THESE BASIC STEPS EACH AND EVERY WEEK OF LAB)
a. Dispose of any remaining organic solids and liquids in the appropriate waste container
b. Dispose of broken or disposable glassware in appropriate containers
c. Clean-up all equipment and glassware according to the directives in Operation 1 of the Lehman text (p. 36-37) – be sure to dispose of any acetone washings in the appropriate waste container
d. Place all clean glassware in its appropriate drawer
e. Clean your work area/bench/fume hood
f. Compile any data, spectra, etc and enter into your lab notebook
g. Be sure to provide any data file information for cross-referencing (e.g. NMR data files)
h. Write up lab summary statement/conclusion
i. Have laboratory partner sign your lab notebook