CHM 211 LABS
CHM 211 ORGANIC CHEMISTRY I
Textbook: Carey's own website at U Calgary
Textbook: Carey's textbook site
I AM YOUR HOST
MR RICE, MS
803-530-4895
ricegs@yahoo.com
LAB MANUAL: Hill and Barbaro,
- Experiments in Organic chemistry
Microscale and Miniscale Organic Chemistry Lab Experiments, 2/e website
LAB #1 INTRODUCTION: SAFETY AND NOTEBOOK
Goggles, long sleeves, covered top shoes.
Bound notebook, ink entries on right hand pages, number all pages
LAB #2 RECRYSTALLIZATION
More Information The University of Toronto at Scarborough has a page that describes the technique for Recrystallization of Crude Solids.
Organic Chemistry Help
LAB #3 MELTING POINT DETERMINATION
See the reuslts and effects of finding the melting point of a pure substance and a misture. Using old type of apparatus. Make sure your thermometer is in the right place and that you do not heat your sample too quickly. Single open sided capillary tubes are used to hold your samples. Be sure that your sample is all the way on the closed end of the capillary tube.
LAB #4 FRACTIONAL DISTIALLATION OF BINARY MIXTURE
A separation of two acetates. Ethyl and Butyl Acetate. Set up apparatus with two packed columns, condensor, and make sure that the boiling chips are in the misture.
LAB #5 GAS CHROMATOGRAPHY
GC uses a carrier gas and possibly a gas that is ignited. The detector type determines the gases used. Helium is a common carrier gas. As is all chromatography, the peaks have retention values. Retention time is the time required for the sample to travel through the GC column. The area of each peak is found using the half hieght width and the peak height. Assuming that the peaks have a trangular shape, the area of hte peaks are 1/2*base*height = 1/2*[half-height width*peak height]. You will confirm the computer/integrater calculations for relative areas using this formula.
LAB #6 THIN LAYER CHROMATOGRAPHY
Compounds will be separated using TLC. The retention value for TLC is the Rf, retention factor. The Rf = [spot distance]/[solvent front distance]. Be careful not to put the spots too close to each other or the edge of the TLC paper. Draw your pencil line on the TLC paper above where the solvent exist in the beaker. Place your spots on the pencil line and above the solvent depth in the beaker. You will use UV light to find your spots. By compoaring knowns and unknown, all spot locations should be identified.
PREPARE UNKNOWNS PROPERLY
ONE UNKNOWN WITH ONLY ONE CMPD
ANOTHER UNKNOWN WITH TWO CMPDS
Be careful to use proper wavelength UV to visualize spots. Remember that Asprin should be BLUE
LAB #7 INFRARED SPECTROSCOPY
A demo lab. Infrared Spectroscopy is used to determine the structure of compound. Infrared, the heat portion of the em spectrum, is due to molecular vibrations. A convenient unit used in IR spectroscopy os the wavenumber or 1/cm. Wavenumbers are used since they are easily converted to energy values. Specific bond types are easily recognized by IR spectroscopy. Solid, liquid, and gas samples may be examined with an IR spectrometer. Solids are ussually mixed with Nujol to create a pasty mass that is readily transferred to the IR cell. Liquids are usually placed a drop at a time between two NaCl plates, then placing the plates into the cell. Some liquids and gases are examined directly in cells specially made for those samples.
LAB #8 PROTON NMR
A demo lab. Nuclear magnetic resonance is another method used to identify the sturcture of compounds. Unlike IR which measures absolute transmittance or absobance at certain frequencies, NMR uses a scale based on the ratio of the [return energy]/[sent energy] called ppm. NMR for C and H are used for the identification of carbon compounds. Hydrogen-1 and carbon-13 each have nuclear spins of 1/2. Due to some quantum mechanics and the 1/2 spins, the number of peaks seen for each type of carbon or hydrogen may be found. The number of peaks for each type of H one more than the number of H's on the nearest neighbor carbons. For most organic compounds, the number of hydrogens attatched to any one C atom will be 3,2, or 1. Consequently, most of the H integrals of an NMR spectrum will be multiples of 3, 2, or 1.
Please remember to limit the spectra to 4 carbon or less acyclic alkanes and alkyl halides.
LAB #9 DEHYDRATION OF 2-METHYL-2-BUTANOL [tert-amyl alcohol]
Acid catalyzed dehydration of 2-METHYL-2-BUTANOL [tert-amyl alcohol] forms two possible organic products and water. The carbocation may wander with a hydride shift to make the most stable product. The reaction will be carried out in two steps. First a reaction step, then an extraction and second distillation separation step.
FIRST REACTION STEP
1. ADD H3PO4 SLOWLY
2. USE VIGREAUX COLUMB + CONDENSOR + ICE ON COLLECTION FLASK
SECOND EXTRACTION
1. ADD SALT SOLUTION
2. BURP UNTIL NO MORE SOUND
3. LET THE LAYERS FORM ON SETTLING
4. DRAIN AND KEEP UPPER TOP LAYER
5. ADD DRYING AGENT TO FLASK WITH PRODUCT
SECOND DISTILLATION
1. SIMPLE DISTIALLATION
2. KEEP BOTH FLASK - JUST TO BE SURE
3. PRODUCTS SHOULD BE IN COLLECTION TRY TO GET TO NEAR DRY
GC ANALYSIS
1. SHOULD SEE 2 PEAKS IN RATIO OF EXPECTED PRODUCTS
2. CHECK BOTH FLASKS AND TRY TO SEE RELATIVE AMOUNTS.
After the products are isolated, GC analysis will be used to show the ratio in which the products formed. The boiling points of the products are low, so use an ice bath for the collection flask and do not seal the reaction with the eye dropper heads.
LAB #10 DIES-ALDER REACTION
Electrocyclic reactions are so fun. Fill the condensor from bottom to top and keep it running if you turn up your heat on the mantle. Otherwise wait for the reaction time, then procede with isolation and identification of products.
LAB #11 PREPARATION OF n-BUTYL BROMIDE
REMIND STUDENTS OF EXTRACTION PROCEDURE
1. MACROSCALE
2. ADD 9M SULFURIC ACID CAREFULLY
3. WATCH YOUR REFLUX RING AND POT TEMPERATURE
4. ISOLATION/SEPARATION SEQUENCE
A. FROM POT MIXTURE - EXTRACT PRODUCT = BOTTOM
DENSITY OF WATER LESS THAN PRODUCT
B. ADD WATER EXTRACT PRODUCT - BOTTOM
DENSITY OF WATER LESS THAN PRODUCT
C. ADD SULFURIC ACID EXTRACT PRODUCT – TOP
DENSITY OF PRODUCT LESS THAN SULFURIC ACID
D. ADD SODIUM HYDROXIDE EXTRACT PRODUCT = BOTTOM
NEUTRALIZE SULFURIC ACID MAKE WATER
DENSITY OF WATER LESS THAN PRODUCT
NOTE
IF SEPARATION NOT COMPLETE BY WATER SODIUM BROMIDE FROM POT MAY FORM SODIUM PHOSPHATE WHEN REACTED WITH SULFURIC ACID. DURING SULFURIC ACID EXTRACTION C, SODIUM SULFATE FORMS AND MAKES EXTRACTIONS DIFFICULT TO IMPOSSIBLE.
Lab Material Sites
Organic Chemistry Helper
Pendarvis U Calgary
OCHeM.com Virtual Lab Tutor
links CU Bolder
Lecture Material Sites
Wade, Preston Hall 4th Edition
Organic Chemistry Helper
Pendarvix U Calgary
links CU Bolder
Still more Angelfire Services