WEAR GLOVES DURING THE ENTIRE PROCEDURE
Bromobenzene and the two nitrobromobenzenes are irritating to sensitive skin areas. If you should have these materials on your hands and then accidentally touch your face, can cause a severe burning sensation in the affected area. If this should happen, IMMEDIATELY:
1. Go to the restroom and wash theaffected area with lots of soap and water.
THE SOAP IN THE LAB IS NOT SUITABLE FOR THIS PURPOSE.
2. Return to the lab and apply mineral oil to the affected area.
3. The summary to this warning is NOT TO TOUCH ANY PART OF YOUR BODY
WHILE PERFORMING THIS EXPERIMENT.
If you must leave the lab for any reason:
1. Firstdispose of your gloves in the waste container
2. Immediately go to the restroom and wash your hands
thoroughly with soap and water.
AGAIN, LAB SOAP WILL NOT DO A SUFFICIENT CLEANING
3. Upon returning to the lab, obtain another pair of
gloves from the front of the room, and proceed withthe experiment.
NITRATION OF BROMOBENZENE
Equation: H2SO4 + C6H5Br + HNO3 --------------> C6H4BrNO2 + H2O
Table of Physical Constants
Compound | M.W. | density | mp | bp |
C6H5Br | 157.0 | 1.522 | -31 | 156 |
o-NO2C6H4Br | 202.0 | ----- | 43 | 258 |
p-NO2C6H4Br | 202.0 | ----- | 127 | 254 |
HNO3 | ----- | ----- | ----- | ----- |H2SO4 | ----- | ----- | ----- | ----- |
Table of Amounts of Reactants and of amounts of Products Theoretically Possible
| C6H5Br | HNO3 | H2SO4 | C6H4BrNO2 | H2O |
M.W. | 157 | 63 | 98 | 202 | 18 |
Moles | | | | | |
Grams | | | | | |
mL | 2.6 130 drops | 5ml | 5ml | | |
M | - | 15.6 | 18.0 | - | - |
-------------------------FOR SAFETY REASONS --------------------------
1. Add 700mL of tap water to your 1 L Beaker.
2. Discard any acid washings, plus the contents of the filter flask (from step 9 below) into your 1 L Beaker, WITH STIRRING.
3. Wash the contents of your 1 L Beaker down the sink.
1. Prepare a mixture of 5 mL conc HNO3 and 5 mL conc H2SO4 in a 25 x 150mm test tube. Cool it toroom temperature by means of a water bath, at your hood workstation. Once the tube has reached 300C as read on your glass thermometer, remove the tube from the water bath, wipe off the outside of the tube, and clamp it to your heating mantle ringstand-suspended over an empty 150 mL beaker. (See figure posted in your hood area)
2. To the tube, add 2.6 mL bromobenzene DROPWISE over a period ofabout 5-10 min; gently swirlling the tube to mix the contents after each addition. Keep the reaction mixture between 50 - 55 oC. DO NOT ALLOW THE REACTION MIXTURE TO EXCEED 60 oC. The temperature may be controlled by allowing more time between the addition of successive portions of bromobenzene and by cooling the reaction flask as necessary with an ice water bath.
3. After the addition iscompleted and the exothermic reaction has subsided, heat the tube for 30 min. in a hot water bath, maintaining the temperature in the reaction vessel below 60oC during this period. The settings on your hot plate should be between dial markings 2 & 3.
4. Cool the tube in an ice bath to room temperature.
5. Pour the reaction mixture into 50 mL of distilled water which is in a 150 mLbeaker.
6. Isolate the crude product by vacuum filtration.
7. Wash the filter cake thoroughly with cold (0-10oC) distilled water and dry the filter cake by allowing the vacuum apparatus to draw air through it after you have finished washing.
8. Transfer the crystals to a TARED 50 mL Erlenmeyer flask and obtain the weight of your wet product. Place the washings into the 1L beaker....