Nitration of Chlorobenzene

               

NOTE

      WEAR GLOVES DURING THE ENTIRE PROCEDURE

Chlorobenzene and the two nitrochlorobenzenes are irritating to sensitive skin areas.  If you should have these materials on your hands and then accidentally touch your face,  this can cause a severe burning sensation in the affected area.  If this should  happen, IMMEDIATELY:

             1. Go to the restroom and wash the affected 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 scenario 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. First dispose 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

                JOB

 

             3. Upon returning to the lab, obtain another pair of

                gloves from the front of the room, and proceed with

                the experiment.

                                                                                                     

 

------------------------- 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.

 

  PROCEDURE

 

 1. Prepare a mixture of 4 mL conc HNO3 and 4 mL conc H2SO4 in a 25 x 150 mm test tube.

    cool it to room temperature by means of an ice-water bath.

 

 2. Add 1.5 mL chlorobenzene to the test tube DROPWISE, using the plastic pipet provided.

    Cork the tube and shake after each drop added.

 

            Should the test tube become warm ( over 35oC ), immerse it momentarily in an ice-water

            bath until the contents are cooled to room temperature before adding more

            chlorobenzene.

 

 3. After the addition is completed and the exothermic reaction has subsided, stopper and shake

    the tube for 5 min, until most of the upper layer of chlorobenzene is gone.

 

 4. Allow the tube to stand at room temperature for 10 mins., to complete the reaction.

 

 5 Pour the reaction mixture into 25 gm. of ice in a 100 mL beaker.

 

 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 after you have finished washing.

 

 9. 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.

 

10. Calculate the volume of 95%(v/v) ethanol needed to just dissolve the

    nitrobromobenzenes at 78.2oC (the boiling point of 95%(v/v) ethanol). You will need

    approx. 5 mL 95% ethanol per gram of crude product.  Now, add 1 mL more of solvent.

    SHOW THIS CALCULATION IN THE PROCEDURE PORTION OF YOUR REPORT.

 

11. Bring this mixture to boiling to dissolve the crude product, then set the flask aside and

    allow the contents to cool slowly to room temp.  If the product does not completely dis-

    solve after 2 minutes of boiling, add 5 mL of 95%(v/v) ethanol.  If solid still remains you

    will have to do a hot filtration.

 

12. Isolate the nearly pure crystals of 4-nitrochlorobenzene by vacuum filtration.

 

13. Wash the crystals with a little ICE COLD ethanol, allowing the washes to drain into the

    filter flask with the mother liquors.

 

DISCARD THE LIQUID PORTION INTO THE ETHANOL RECOVERY BOTTLE PROVIDED IN HOOD #1.

 

WASH DOWN YOUR BENCHTOP WITH A SMALL PORTION OF 95% ETHANOL ON A PAPER TOWEL.  THROW THE PAPER TOWEL INTO THE TRASH.  DO NOT USE THE LAB SPONGE TO WIPE DOWN YOUR BENCHTOP !!!!!*

 

14. Allow the crystals to dry overnight in the top of your filter funnel

 

15. Determine their weight and melting point. WASH YOUR BENCHTOP AS ABOVE.*

 

16. Place your product in the recovery jar in Hood #1.