Chem 334 Organic Chemistry Laboratory I 334-FPBP and 334-07 Welcome to Chem 334 Organic Chemistry Laboratory I 334-FPBP and 334-07 M. Séquin

Instructor: Dr. Margareta Séquin Office: Science 106 C Office Hours: Tu 11 – 12; Th 1 – 2 pm; Fr 1 – 2 pm e-mail: msequin@sfsu.edu For phone messages: 415 – 405-0315 CHEM 334 Expt 1 Lecture

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 average 20% Lab preparation, notebook, lab skills, maintaining clean work area, observing safety rules, participation, attendance.

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very common organic lab techniques 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; Recrystallization 9/15: Exp. 2c 9/22: Molecular Modeling. Go to SEGA lab, SCI 249 9/29: Exp. 3, Distillation and Gas Chromatography 10/6: Exp. 4, Isolation of Eugenol. IR 10/13: Exp. 10, Isolation of Caffeine 10/20: Exp. 6, Column Chromatography 10/27: MIDTERM EXAM in Lab. Complete Exp.6 11/3: 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

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

Measuring Melting Points Procedure: Simple Capillary Melting Point Each instrument and thermometer have slightly different calibrations. Use the same instrument each time. Melt-Temp melting point apparatus

Melting Point Measurements T = Temperature Measure : m.p. range: T start melting - T completely melted Example: m.p. 98 - 100 oC

Chemical Structures relevant to this experiment Expt. 1 Melting Points Chemical Structures relevant to this experiment o-anisic acid Mp.: 98-99o phenoxyacetic acid 98-100o Acetanilide 113-114o Fluorene 114-115o malic acid 131-143o diphenylacetic acid 147-149o Cholesterol 147-149o Urea 132-134o

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 Cmpd. name Expt. M.P. Lit. M.P. Unkn # 1a 1b 1c 1d

Part A: Melting Pt of Mixture 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.

Table 3. Mixed M.P. Data (p. 247) Expt. Expt. 1a 1b 1b 1c 1c 1d 1d 1a Cmpd. MP Cmpd. MP Predict. M.P. Expt. M.P. M.P. mix of 1a + 1b 1a 1b 1b 1c 1c 1d 1d 1a 1a 1c Optional 1b 1d Optional

Melting Behavior of a Binary Mixture (see Reading Assignment) . . m.p. pure B m.p. pure A TF Solid B + liquid A+B . Solid A + liquid A+B m.p. of E (TE) E Solid A + Solid B A 100 80 50 0 0 50 100 B % Composition

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 %

Next class: Wrap up Exp. 1: “Melting Points” Introduction to Exp. 2: “Recrystallization”