This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: CHM 2201 Fall 2009 Department of Chemistry
Organic Chemistry Lab 1 Villanova University
Preparation/Recrystallization of Acetanilide
Week 2 — August 31 - September 4 , 2009
From Bell, Clark and Taber, pgs 30, 31
E) + (CH3CO)20 + CHSCOZH
. . Acetic acid
Armin Acetic anhydrlde Acetanmde
9 MW: 102.09 MW: 135.16
MW = 93_13 d = 1.08 g/mL Theoretical yield: 9
d = 1.02 g/mL 7 drops = ~220 uL Conduct this Experiment in your hood. Aniline is toxic and acetic anhydride is an irritant
to the eyes and nasal membranes. 1. U) 10. 11. For use in step 5, prepare ahead of time a hot water bath by heating a 250 or 400
mL beaker ﬁlled about 1/2 to 3% full with water on a hotplate. Have a TA place 125 [1L of aniline into a dry 13 x IOO-mm test tube. Add 2 mL of water to the test tube containing the aniline. Add 7 drops (~220 pL) of acetic anhydride to the test tube and gently stir the
resulting mixture with a spatula until a solid (the acetanilide product) forms.
NOTE: If you use more than 7 drops of acetic anhydride, you may not obtam
solid and will have to start over. Add 4 mL of water to the test tube containing the solid and heat the test tube in a
hot water bath with occasional stirring (spatula) until the solid dissolves. Allow the test tube to cool for 5 minutes and then place it in an ice bath for 5 — 10
minutes to thoroughly cool the mixture and to complete the crystallization. Use a spatula to break up any lumps of crystals that have formed during the
crystallization process and to ensure that the crystals are evenly suspended in the
water. Set up a vacuum ﬁltration apparatus using your small Hirsch funnel, a 50 mL
ﬁlter ﬂask, and a rubber adapter (place the funnel in this adapter which is ﬁtted on
top of the ﬁlter ﬂask). To prevent the ﬁlter ﬂask from tipping over, clamp it to a
bar in your hood. Using a vacuum hose (use the black thick-walled hose), connect the ﬁlter ﬂask
side arm to the house vacuum outlet in your hood. Place a small ﬁlter paper on the Hirsch funnel (be sure all the funnel perforations
are covered by the ﬁlter paper) and moisten the ﬁlter paper with a few drops of
water. Turn on the house vacuum and then pour the contents of the cold test tube onto the funnel.
(continued) Page 1 of 2 CHM 2201 Fall 2009 Department of Chemistry
Organic Chemistry Lab I Villanova University 12. Add a small quantity of i_ce go_ld water to the test tube and swirl or scrape loose
the solids remaining in the tube and rinse the resulting suspension into the funnel. 13. Leave the vacuum on and allow air to draw through the collected solids on the
funnel for ~10 - 15 minutes to remove as much water as possible from the solids. 14. While air is being drawn through the solid, use a spatula to carefully break up the
solid cake of crystals to facilitate air drying. Be careful not to tear the ﬁlter paper
during this scraping/breaking process. 15. When the solid appears to be dry and free ﬂowing, use a spatula to remove the
solids to weigh the dried material. If the weight of your product is MORE than
the calculated theoretical yield, the acetanilide is still wet and requires additional
drying l6. Determine the melting point range of your material for comparison with the
literature value and calculate the actual yield of your product. TMBare 8/2009 Page 2 of 2 ...
View Full Document
This note was uploaded on 02/20/2012 for the course CHE 118 taught by Professor Shaw during the Winter '10 term at UC Davis.
- Winter '10