Chemistry 317, Organic Chemistry Laboratory, Fall 2008

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),
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 into contact with your clothing, skin, or mucous membranes. Your safety goggles, laboratory apron and rubber gloves will help. Work carefully and safely during your 317 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.

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 and Spectral Notebooks
40% Experimental Results and Products
20% Exams (2 of them)
20% Personal Estimate

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 2 right hand pages for the table of contents for 317, 319. Remember that all entries are to be in ink. Place a single line through any mistake. 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.

Synthesis Experiments [A -----> B] (Parts a-c below are completed prior to the laboratory period)

a) Title of the Experiment

b) 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 316-317, Cal Poly, Spring 2008 ).

c) Chemical Reaction and Quantities of Materials (An example is shown below for the commercial like manufacture of solvent grade ethanol.)

d) Procedure (This is the actual account of your work. It is what you did, and it is to be written in the past tense while avoiding the first person. Be sure to keep track of date and time that any work has been done. This is a big help in repeating experiments and in troubleshooting. See the example below for the hydration of ethylene indicated in the equation above.)

23 September 2008

8:30 - Ethylene gas (2.24 liters, 100mmole) was metered into an evacuated 2.5 liter bulb.

8:45 - Water (3.6g, 200mmole) was injected into the bulb along with 12N HCl (1.0ml,12mmole).

8:55 - The sealed bulb was heated to 150oC with an electrically heated oil bath for a period of one hour.

9:55 - After that time the bulb was allowed to cool and ........................etc.

Note how the procedure is written in the past tense since I am recording that information after each task is completed. Also notice that I have avoided the use of "I or my" in the procedure. This is a convention we follow. Be sure to include enough detail in the procedure so it may be reproduced by another chemist familiar with the subject.

e) Signature (Place your signature immediately below each day’s entries.)

f) Conclusion and Presentation of Results (In this section you tell the story in a condensed form presenting documentation for the results which you have received. Look below for an example of what you might say.)

After chemical drying and micro-distillation 4.1g(89%) of material was obtained that had a boiling point of 77.5-78oC. My yield was 3% better than that reported for the same procedure in the literature. The boiling point of my material correlated well with the reported literature value of 78oC and I am therefore confident that the reaction was successful in producing the product in reasonable purity. In addition, we were able to obtain an IR spectrum that showed the characteristic absorptions at 3600cm-1 and 1250cm-1 for the H-O and C-O stretch of the alcohol.

Note how I have tried to address the following questions: Did the experiment work? How do you know that it did? How well did it work? Always address these questions in your conclusion section. If you have other things to report that is fine.

Non-synthesis Experiments (Parts a-c below are completed prior to the laboratory period.)

a) Title of the Experiment and Date

b) A Reference (Your procedure is a result of what source ? Did you go to the literature to find a procedure, or was it the Laboratory Handout for Chemistry 317?)

c) A Brief Description of the work to be done and a Purpose clearly stated

d) Procedure, Data, Notes, Results (See the comments for this section which are given in the synthesis experiment.)

e) Signature (Place your signature immediately below each days entries.)

f) Conclusion (See the comments for this section that are given in the synthesis experiment.) 

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:

name of the experiment	percent yield (for a synthesis experiment)
draw the structure of the product	physical property (m.p. or nD)
actual mass	your name

Laboratory Exams:

A laboratory midterm and final will be given during the quarter. They are scheduled for the 5th and 11th week of the term.

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://scistore.cambridgesoft.com/sitelicense.cfm?sid=797 (Free download of ChemDraw Std 11.0 is currently unavailable).
http://hazard.com/msds/index.php (University of Vermont archive of material safety data sheets).
http://www.sigmaaldrich.com/ (Catalog of chemical supplies including useful physical properties and some MSDS information. Use search products).
http://webbook.nist.gov/ (An additional site for IR, UV, mass spectra and other chemical information).

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.

1. When you are attempting to create a vacuum seal for your apparatus, you must use grease (e.g., in a vacuum distillation, or on permanent fixtures of the rotary evaporator or a similar apparatus).
2. Grease must also be used when you have created a basic reaction mixture. Base is notorious for causing ground glass joints to fuse. This concern over basic reaction mixtures applies not only to solutions containing common bases such as sodium hydroxide, but also to those containing alkoxides and hydrides.

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.