welcome to chem 334 organic chemistry laboratory i 334-fpbp and 334-07 m. séquin
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Instructor: Dr. Margareta Séquin
Office: Science 106 C
Office Hours: Tu 11 – 12; Th 1 – 2 pm; Fr 1 – 2 pm
e-mail: [email protected]
For phone messages: 415 – 405-0315
Prerequisite: passing grade (C- or better) in C 115, C 333 or C130 (can be taken concurrently). A student who withdraws from C 333 or C130 must also withdraw from C 334.
Text: “Chem 334, 336, and 338 Organic Chemistry Laboratory”, SFSU 2005, with Mayo, Pike, Trumper, "Microscale Organic Laboratory", 4th Edition; Wiley Custom Edition.
Laboratory Materials: Laboratory safety glasses (ANSI Z87) or safety goggles
Laboratory notebook, must be bound (not spiral)
Exams and Grading• Several MiniQuizzes at the end of lab lectures, 2 pts. each • One Midterm Exam (100 points) on October 27, in your lab,
covering the material of lab and lab lecture during the first half of the semester. The exam will be given in the respective lab sessions.
• Final Exam (150 pts.) on Dec. 15, in your lab, comprehensive. The exam will be given in the respective lab sessions.
Please note: An exam not taken earns the grade F.• Standard lab reports: 20 points/ lab report. Lab report Exp.9 is 30
points. Late reports incur point deductions.• Lab Notebooks will be checked regularly. Total class grade will be calculated as follows:40% Exam average (Midterm (100 pts.), Final Exam (150 pts.) and Mini
Quizzes (each 2 pts) 40% Lab reports average20% Lab preparation, notebook, lab skills, maintaining clean work area,
observing safety rules, participation, attendance.
Chem 334
An introduction to
very common organic lab techniques
• Methods to identify organic compounds• Methods to separate organic mixtures
Lecture Lab
SCHEDULE OF LAB EXPERIMENTS
(Refer to your text for Reading Assignments and Procedures)
9/1: CHECK IN. Safety rules. Exp.1, Melting points
9/8: Exp. 2ab; Recrystallization9/15: Exp. 2c9/22: Molecular Modeling. Go to SEGA lab, SCI 2499/29: Exp. 3, Distillation and Gas Chromatography10/6: Exp. 4, Isolation of Eugenol. IR10/13: Exp. 10, Isolation of Caffeine10/20: Exp. 6, Column Chromatography10/27: MIDTERM EXAM in Lab. Complete Exp.611/3: Exp.8, Dehydration of 2-Butanol. GC 11/17: Exp.9, Separation of an Unknown Mixture
12/1: Exp.9 Cont.
12/8: Complete Exp.9. CHECKOUT
12/15: FINAL EXAM in Lab.
Exp.1: Melting points of organic solids
• Which has the highest melting point?
CO2, C6H12O6, NaCl, C5H10, C6H6
• Definition of “melting point”?
Measuring Melting Points Procedure: Simple Capillary Melting Point
• Close-up view of the white crystals in the capillary tube before heating the apparatus.
• M.P. range is the temperature at which solid starts to melt to the temperature at which solid is completely melted.
Thomas-Hoover m.p. apparatus
• Each instrument and thermometer have slightly different calibrations. Use the same instrument each time.
Melt-Temp melting
point apparatus
Measuring Melting Points Procedure: Simple Capillary Melting Point
Melting Point Measurements
T = Temperature
Measure :
m.p. range: T start melting - T completely melted
Example: m.p. 98 - 100 oC
o-anisic acid
Mp.: 98-99o
phenoxyacetic acid
98-100o
Acetanilide
113-114o
Fluorene
114-115o
malic acid
131-143o
Urea
132-134o
diphenylacetic acid
147-149o
Cholesterol
147-149o
Expt. 1 Melting PointsChemical Structures relevant to this experiment
Question of the Day:How does the melting point of two compounds compare to the melting points of the individual compounds?
E.g. pure Phenoxyacetic acid (m.p.98-100 oC) mixed with pure anisic acid (98-99oC)?
Or
Pure Fluorene (m.p.114-115 oC) mixed with pure anisic acid?
?????
Expt 1. Melting Pt of Pure Sample
•You will work in teams of 4 students
•Each student will receive one unknown (1a, 1b, etc)
•Make m.p. measurement of your unknown (pure compound). Note in your lab notebook and on the report form.
•Once your team obtains m.p. range for each unknown, see lab instructor to find out the names of each unknown.
Table 2. M.p. of Pure Compds (p. 247)Example for students in Group 1
Unkn # Cmpd. name Expt. M.P. Lit. M.P.
1a
1b
1c
1d
Procedure
•Student with sample 1a will take a small amount (~10 mg or small amount on a metal spatula) and place it on a clean watch glass and then add a similar amount of sample 1b to make the mixed sample. Stir the solid and break the clumps. Mix the sample well.
•Place the mixed crystals in a melting point capillary tube to the height of about 2 mm. Obtain the M.P. range and record it in Table 3.
•Similarly, mix sample 1b with sample 1c etc. as shown in Table 3 example on the next slide.
Part A: Melting Pt of Mixture
Table 3. Mixed M.P. Data (p. 247)
Cmpd. Predict. M.P. Expt. M.P.
1a
1b
1d
MP
1a 1c
1b 1d
1b
1c
1d
1a
Optional
Optional
M.P. mix of 1a + 1b
Expt. Expt.
Cmpd. MP
1c
Melting Behavior of a Binary Mixture(see Reading Assignment)
.
.
.m.p.
pure A
m.p.
pure B
A 100 80 50 0 0 50 100 B
% Composition
E
Solid A+ liquid A+B
Solid A + Solid B
Solid B
+ liquid A+B
TF
m.p. of E
(TE)
Melting Behavior of a Binary Mixture(see Reading Assignment)
Some key words and expressions (which you should look up and be able to define):
Eutectic point, eutectic mixture, mole %