City College of New York
Department of Chemistry and Biochemistry
CHEM 37400: Organic Chemistry Laboratory 2
Lecture: 50 min; Lab: 4 hr 50 min
Hours: 6 hr./wk; 3 cr.
Prerequisites: CHEM 26300 and either 26200 or 27200. A grade of C or higher is required in the prerequisite courses.
Text: C.F. Wilcox, M.F. Wilcox, "Experimental Organic Chemistry, A Small-Scale Approach", (2nd edition).
The laboratory techniques described in Chapters 1 to 15 are widely used in an organic chemistry laboratory. The physical theory of these techniques is also described in these chapters. Sections of the chapters 1 to 15, especially chapters 1 to 10, must be read carefully and frequently. Chapters 16-56 describe reactions used in preparative organic chemistry and exercises found in these chapters will be performed.
Organic Chemistry Laboratory II will build on the basic skills and operations of a synthetic organic chemistry laboratory and introduce advanced techniques. Stress will be placed on the identification and isolation of the products of common reaction types as well as use of Infrared and nuclear Magnetic Resonance Spectroscopy. To this end, we will develop the basic skill set introduced to you in Chem 262/272 and extend the set to include advanced methods for the execution of reactions, isolation and purification of crude product, identification of pure product, and purification and identification of unknown materials. You will be introduced to advanced equipment used in the Organic Laboratory to safely carrying out reactions, isolation and purification of crude product, identification of pure product, and purification and identification of unknown materials. In addition, you will perform exercises in reaction evaluation and product purification using chromatographic methods as well as spectroscopic and chemical identification methods on purified products.
After completing this course students should be able to:
1. Understand the fundamental principles and theory behind organic laboratory techniques commonly used for purification of compounds and separation of reaction mixtures, monitoring the course of the reactions, and analyzing reaction mixtures and products.
2. Use advanced techniques and equipment such as, vacuum distillation, soxhlet extraction, steam distillation, TLC, and GC to isolate and purify crude product and unknown materials.
3. Identify purified chemicals using spectroscopic methods (e.g. FT-IR, FT-NMR, GC-MS).
4. Identify purified chemicals using chemical methods (e.g. reactive indicator tests such as Tollen's test).
5. Perform organic reactions in different environments (e.g. air sensitive reagents, multi-step synthesis, solid-phase synthesis, and “green chemistry”).
6. Demonstrate proficiency in recording and evaluating experimental data including maintaining a proper laboratory notebook.
7. Write a proper laboratory report including abstract, introduction, experimental methods, results, discussion, and references.
8. Follow the safety requirements for an organic chemistry laboratory.
9. Access and utilize chemical information technology for proper experimental design and interpretation.
10. Apply ethical responsibilities and professional conduct in laboratory.
Laboratory Exercises: 4 preparative exercises and 3 technique exercises will be performed in this lab course. An exercise consists of one to many steps. It is expected that for each exercise a separate laboratory report is written.
The Laboratory Report: All your lab work should be recorded in a lab notebook and not on scraps of paper. Data recorded in the notebook must be properly dated, and neatly written. Based on this information, you will generate a laboratory report that needs to be submitted on time for grading.You are to submit hardcopy type-written reports. Handwritten reports will not be accepted. Your TAs will provide the rubric tailored to each experiment. A general format for a synthesis-type laboratory report is provided below (total point is 10 for each lab).
Name, ID number and section
Title of experiment
Theory and objective of the experiment
Reaction and Mechanism: Any equations chemical structures relevant to the experiment as well as any pertinent mechanisms.
Physical Properties: A table listing the compounds used, their molecular weights, amounts used in grams and moles, boiling points and density (for liquids), as applicable
Hazards: determine flammability, toxicity or corrosiveness of the compounds used in this experiment.
Limiting Reagent: Based on the balanced equation in section 1, calculate the limiting reagent of the reaction
Theoretical Yield: Calculate the theoretical yield of the experiment
Side Reactions: Try to postulate possible side reactions that might lower the yield of the reaction
Separation Scheme: The separation scheme is a flow chart that illustrates how the compound is isolated or separated from the reaction mixtures once the reaction is done.
Procedure and Observations: Describe exactly how you performed the experiment and exactly what observations were made (e.g., color change, if any spillage occurred etc.). The observations have to be very specific. Draw a separation scheme or a flowchart. Always write this part in the third person and in past tense.
Results: This part should include identification of the limiting reagent and calculation of the theoretical yield of the product. Actual yield of the product, physical properties of the compounds such as color or nature of product (e.g., colorless needles of compound X were obtained). Melting or boiling points.
Conclusion & Discussion: Did you achieve what had to be achieved? Did you have any problems? Other scientific comments on the experiments, such as suggestions if you feel you could do something differently to improve the outcome of the experiment.
Sections 1, 2, and an outline of 3 should be prepared at home, during the week preceding the first laboratory session for the new experiment. This preliminary laboratory report must be ready at the beginning of the lecture of the laboratory session for that experiment. Section 4 must be completed in the laboratory. The completed laboratory report must be handed in on the last day assigned for the particular experiment. Failure to do so may result in a 10% - 50% point penalty for the report grade.
The sections of the report are discussed in the textbook on pages 10 to 18, and pages 531 to 534 (Appendix D). Note that we require a slightly different sequence for the presentation of the sections than is described in the textbook; however, the textbook will provide valuable information and samples for you to follow in the proper preparation of the laboratory report.
The final exam: The final exam will test your knowledge on the theoretical basis of the exercises that are performed and will be conducted to evaluate your preparedness for the experiments. They will be based on the lectures delivered at the beginning of each lab, the theory of the experiments performed, the conceptual aspects and the techniques applied.
The chapters which describe techniques especially relevant to each exercise are listed on the schedule with the exercise numbers. You are strongly advised to read the chapters in the textbook.
Make-up Sessions, Absences: Unless in an extraneous circumstance, no make-up exams, or laboratory sessions, will be arranged. It is your responsibility to ensure that you attend all the laboratory sessions, on time. An absence from a laboratory without a suitable strong excuse will result in a score of zero being assigned.
Grading: There are 13 experiments, some relate to techniques, some to reactions and mechanisms, and some are aimed at synthesis of compounds. Of the 13 experiments, the best 12 will be used in computing the final grade.
Laboratory reports for each experiment must be handed in no later than one week after completion of that experiment.
Student laboratory performance will be evaluated by the TA (as well as professor) and is worth a total of 5 points. That includes your work skill, punctuality and attendance in both lecture and lab. A summary of the points assigned to each portion of the course is shown below.
Experiments 13 in all, best 12/13 x 10 points each = 120 pts = 50%
Midterm exam = 20 %
Final exam (comprehensive) = 25 %
TA/instructor evaluation = 5 %
TOTAL = 100%
Safety: All of the safety regulations that are outlined in chapter 1 must be adhered to. (Safety goggles will be worn at all times. Neither contact lenses, nor open-toe shoes are allowed in the lab). Any willful violation of our safety rules will result in the student’s immediate expulsion from the laboratory and the award of a grade of F.
Breakages: You will be charged the replacement cost of any equipment which you break during the lab course. Some glassware are extremely expensive. Therefore, handle them carefully.
TENTATIVE SCHEDULE OF EXPERIMENTS
Introduction, Lab Safety, Check In, Chemical Literature Search; FT-IR (ATR) instrumentation and orientation
Ref: Chapter 13
NMR Spectroscopy. Lecture, Problem Solving, and Homework
Introduction of NMR instrumentation and orientation
Ref: Chapter 15
Esterification reaction using an unknown alcohol.
Identification of an unknown alcohol by NMR; TLC.
Saponification – base hydrolysis of an ester
Analysis of product by FT-IR (ATR)
Diels-Alder Reaction: Two-step reaction – synthesis of N-Phenyl-4-cyclohexene-1,2-dicarboximide (precursor and adduct). Analysis of product by TLC, FT-IR (ATR)
Part I: Steam distillation or Part II: Soxhlet Extraction. Separation of Cinnamaldehyde from Cinnamon Sticks via Steam Distillation or Soxhlet Extraction
Part II: Soxhlet Extraction. or Part I: Steam distillation Separation of Cinnamaldehyde from Cinnamon Sticks via Steam Distillation or Soxhlet Extraction
Part III: Synthesis, IR, wrap-up. Synthesis of Cinnamaldehyde from Cinnamyl alcohol
Part IV: IR, GC-MS, and 1HNMR Analysis. Characterization of Cinnamaldehyde by IR, GC-MS and 1HNMR.
Expt 40.3 A, B
Liquid Column Chromatography. Isolation of [R]-[-]- Carvone from Spearmint Oil or [S]-[+]-Carvone from Caraway Seed Oil
Part I: Functional group analysis by chemical test reactions. Identification of two unknown compounds
Part II: Structure Identification by NMR and Mass Spectral analysis (No IR). Identification of two unknown organic compounds
Final Exam; Check Out.
Make-up lab (just in case…); Check Out