Instructor: Michael
G. Silvestri
Office: FOE 25-335
Phone: 756-1686
E-Mail: msilvest@calpoly.edu
Website:
http://www.calpoly.edu/~msilvest
Textbooks:
"Organic Laboratory Techniques", by Fessenden, Fessenden and Feist,
"Laboratory Manual for Organic Chemistry" (Available at El Corral).
Materials:
Safety Goggles (rated Z-87 or better), a pair of Rubber Gloves (not surgical type),
Protective Apron will be provided
Bound Laboratory Notebook and a Lock for your drawer
Safety: In general chemistry laboratory you learn to work carefully so that you may obtain good results from your effort. In organic chemistry you will work carefully not only to obtain good laboratory results, but also to avoid potential accidents. Even though our exercises have been carefully screened to limit potential hazards and disaster, a single careless act could change that picture. As better methods of testing have become available, chemicals once thought to be without hazards are now suspects. Toxic, irritant, and cancer suspect agent have become common descriptions for many organic chemicals. In addition, the majority of organic chemicals are at least moderately flammable, and they possess significant vapor pressure that makes their inhalation a possibility. You must avoid allowing chemicals to come in contact with your clothing, skin, or mucous membranes. Your safety goggles, laboratory apron and rubber gloves will help. Work carefully and safely during your 316 laboratory, and remember that the hazardous nature of many organic molecules is balanced by their participation in the preparation of helpful materials, including medicinals to treat burns, inflammation, infection, cancer, heart disease, mental illness and more. One of the early realizations of a chemistry student is the large number of hours that are required in the laboratory. There are no two ways about it, your friends in non-science classes can sit in the sun and do their reading assignments while you spend 6-20 hours per week in the laboratory. Don't fight it or try to rush it. This is a sacrifice we make as scientists and professionals.
Purpose: In the 316 laboratory we will expose you to the most common techniques used by the practicing organic chemist, and in addition, we will help begin the building of your intuition about the nature of organic chemicals. Methods of separation, purification, identification, and purity assessment will be stressed in 316. You will learn to prepare at least one useful material, and set the stage for further explorations in 317 and 319.
Grading: A laboratory grade based upon 100% will be compiled with your lecture work to determine your final score for the course. The average lab score is usually about 80% while the minimum passing score is 60%. You must receive a 60% or better grade in laboratory to pass the lecture part of the course. The 100% is based upon the following parts:
20% Laboratory Notebook
35% Experimental Results and Products
25% Exams (2 of them)
20% Personal Estimate
Useful Websites:
http://www.chemfinder.com
(For chemical structure and physical property searches).
http://riodb01.ibase.aist.go.jp/sdbs/cgi-bin/cre_index.cgi?lang=eng
(Excellent source for viewing and downloading IR, HNMR, 13CNMR and
mass spectra).
http://www.mdl.com
(After login and registration at this site, go to dowloads for a free ISIS/Draw
in Mac or Windows versions).
http://hazard.com/msds/index.php
(University of Vermont archive of material safety data sheets).
http://scistore.cambridgesoft.com/sitelicense.cfm?sid=797 (Free download of ChemDraw Std 11.0 in Mac or Windows
versions).
http://www.sigmaaldrich.com/
(Catalog of chemical supplies including useful physical properties and some
MSDS information. Use product search).
http://webbook.nist.gov/ (An additional
site for IR, UV, mass spectra and other chemical information).
Laboratory Notebooks:
Purchase a hard bound notebook with lined format and prepare it by writing page numbers in all of the upper right hand corners beginning with 1,2,3, etc. You will treat the left-hand page, or the back of each page as you may prefer to view it, as a place for note taking and calculations. The left-hand pages are substitutes for paper towels or loose notepaper. Your organized laboratory material will be placed on the right hand pages. Save the first 3 right hand pages for the table of contents for 316, 317, and 319. Remember that all entries are to be in ink. Place a single line through any mistakes. Don't try to erase or use a WhiteOut material.
There are really two types of experiments that are done in our organic chemistry laboratory. Two slightly different lab book formats are used. We will first use the non-synthesis format.
(Parts a-c below are completed prior to the laboratory period.)
a) Title of the Experiment (e.g., Simple and Fractional Distillation)
b) A Reference (Your procedure is a result of what source ? Did you go to the literature to find a procedure, or was it e.g., Laboratory Handout for Chemistry 316, Cal Poly, Summer 2009 ).
c) A Brief Description of the work to be done and a Purpose clearly stated (e.g., A comparison between simple and fractional distillation will be performed, utilizing as a test solution, a 50:50 mixture of ethanol and butanol. Throughout the distillations, temperatures will be monitored and samples will be collected for analysis through gas chromatography and refractive index measurements.).
d) Procedure, Data, Notes, Results (e.g. below)
23 June 2009
12:20 - An apparatus was assembled for simple distillation.
12:40 - Three boiling stones were added to the round bottom flask, and 60ml of a 50:50 mixture of ethanol and butanol was added via a glass funnel.
12:45 - The thermometer was positioned over the three-way adapter, and the flow of water in the condensor was started.12:50 - The heating unit was turned on high for a few minutes until some gentle boiling was observed in the round bottom flask, and then the setting was adjusted to 4.5 to maintain a desirable reflux................etc.
e) Signature (Place your signature immediately below each day's entries.)
f) Conclusion - In general you will try to answer three basic question. 1) Did the experiment work? 2) How well did it work? 3) How does the evidence of the experiment support your assertion? I am looking for substantive and in-depth conclusions.
Laboratory Reports:
After the completion of some experiments a short report will be required. This report will serve two functions. It will encourage you to review the experiment in a thoughtful manner, thereby reinforce your learning, and it will allow practice in writing and presenting scientific information. Regardless of your discipline, you will be expected to report scientific information in your careers. The reports must be typed double-spaced. I will give you further guidelines on the report writing later.
Products:
Any material that you prepare or purify will be turned into to me. It will be necessary to place the sample in a screw-cap vial with a label describing the contents. On each label I want the following information:
experiment name percent recovery structure of product physical property (m.p. or nD) actual mass your name
Laboratory Exams:
A laboratory midterm and final are scheduled for the 4th and 8th week of the term.
Use of Grease on Ground Glass Joints:
A) When do you need to use it?
Evolution is a curious phenomenon. At one time, Bunsen burners were frequently used to heat mixtures of organic materials. With the development of efficient electrical sources of heat and the use of Teflon as a material for stopcock valves, etc., the use of grease to seal ground glass joints has fallen far to the wayside. There are however, two legitimate times when grease should be used.
If you develop the good habit of not using grease, remember to use it when it is essential.
B) Why should the use of grease be restricted?
Most greases used for ground glass joints are soluble in organic solvents. This means that the grease will eventually work its way into your solvents, and into your final product. You will not find an experimenter who is accustomed to working on small scale, use grease, except in the instance of vacuum distillation or vacuum transfer. Teflon tape is sometimes used in place of grease for small-scale reactions. On larger scales, washing grease into your solvent and eventually into the product is common, although somewhat less annoying.
C) Keep your ground glass joints clean and sparkling.
We commonly remove grease with solvents such as ligroin (30-60), hexane, or dichloromethane. A ground glass joint can be dipped into a small beaker of one of these solvents and wiped quickly with a Kimwipe before drying (Use your gloves!). The resultant is an opaque joint surface.
When using grease for a reaction, be certain to remove it before attempting to pour your contents out of the flask. Wipe the bulk of the grease away with a dry Kimwipe, then use a Kimwipe wet with one the degreasing solvents to remove the remainder of the grease (Use your gloves!). Remember that small amounts of materials can best be removed from flasks with disposable pipettes, rather than by pouring.