Electrophilc aromatic substitution part 2 lab report Instructions (2)

docx

School

Temple University *

*We aren’t endorsed by this school

Course

1951

Subject

Chemistry

Date

Feb 20, 2024

Type

docx

Pages

Uploaded by AdmiralStarToad7

Lab-report (40 points) CHEM 2924/ 2214 Lab Report Instructions: General Information ● Your report MUST be typed and should NOT be submitted on laboratory notebook pages. Much of the information and data from your lab notebook will be transferred to your report, but you will not submit any lab notebook pages with or as part of your report. ● The lab report is due at the beginning of the lab period on the week following the completion of the experiment for full credit. ● Each lab report is worth 40 total points. General Format The lab report will consist of the following sections. Use the headers listed below to designate each section in bold. ● Top of Page (no separate cover page is necessary): Name, Section Number, TA Name, Date the lab was performed, Due Date of Report, Experiment Number, Experiment Title--2 points ● Objective--2 points ● Experimental Procedure--2 points ● Reaction Scheme--2 points ● Data and Results--7 points Data and Results Table Observations Calculations ● Data analysis and discussion--5 points ● Questions (Answer the questions)--17 points ● Write two thoughtful, researchable questions--2 points ● Works Cited--1 point

Specific Information for Each Section CHEM 2214/2924 SP 2024 Lab Report Instructions for Expt 28: Electrophilic Aromatic Substitution Part 2: Purification and IR Spectrum Analysis Title : The title of the experiment, the experiment number, and the date that the experiment was performed in lab. This information is identical to that required in your pre-lab write-up. The title should be complete and accurate and your own words. Objective : List the goals, or the purpose, of the experiment. List the names of reactants and products (for a reaction) and the isolation/analysis techniques. This information is identical to that required in your pre-lab write-up. Your objective for this week’s experiment should focus on the technique of recrystallization as applied to the purification of your crude reaction product from Part 1, as well as IR and NMR spectral analysis. Experimental Procedure : You do NOT need to copy the experimental details that were included in your pre-lab write-up. It is sufficient to include a reference to the source of the procedure, as well as any modifications that were posted on Blackboard. If necessary, these statements should be followed by a list of any additional modifications to the experimental procedure . It is very important that you document any changes to the procedure in your lab notebook at the time of the experiment, and include them in your report. This section may help to explain unexpected results, for instance. Reaction Scheme : A balanced chemical reaction consistent with the experiment being conducted, including reactants, products, solvent(s), and reaction temperature . This scheme is identical to that required in your pre-lab write-up and should immediately precede the Data and Results Table (see below). The reaction scheme may be handwritten, but please be as neat and clear as possible. For this report, simply copy and paste the same reaction scheme that you submitted with last week’s report (for Part 1 of Experiment 28). If you made any errors, please correct them! Data and Results : Organized in three parts as shown below. Data and Results Table Give original data and calculated values in an organized tabular format, essentially, an updated version of the Reaction Table from your pre-lab. · Include appropriate units and pay attention to significant figures.

· Data may differ slightly from that reported in your pre-lab write-up. You must report and use the actual values in your calculations. In this way, your final results and conclusions match what you actually did in the experiment, not what you intended to do in your pre-lab. · The product amounts in the table (g or mg and mmol) should represent the calculated theoretical yield based on the reaction stoichiometry. The experimental yield should be reported in the Calculations section of the report (see below). Omit the Data and Results Table for this report because the completed table was submitted with last week’s report (for Part 1 of Experiment 28). Please include here the amount of acetanilide used in Part 1, and the calculated theoretical yield . Correct any errors in the theoretical yield calculation in the Part 1 report! Edit the TLC table to include the TLC of the pure product Observations Data includes all relevant observations , such as heat evolved, initial color and color changes, precipitate formation, state and color of product, TLC comparison, product melting point range , etc. Observations should be listed in bulleted, complete sentences. Calculations For all calculated values in Chem 2214/2924, show ALL work . This part does not have to be typed, and you may prefer to leave space in your document and enter the calculations by hand. Please be as neat as possible. 1) Yield of crude 4-bromoacetanilide after drying for one week 2) Yield of recrystallized 4-bromoacetanilide 3) % Yield of 4-bromoacetanilide for the purification step = (recrystallized yield/crude yield) x 100--grade based on this yield 4) % Yield for the bromination reaction = (recrystallized yield/theoretical yield) x 100---yield 5) Rf values Yield 4 points: Greater than 100%-3 points, 85%-100%-4 points, 70-84%-3 points, 60-69%- 2 points, 50-59%- 1 point. Less than 50%---no points Once again, be sure that your theoretical yield from Part 1 is included in the Data and Results section, and correct based on the amount of acetanilide used in the reaction. Data analysis and discussion: Analyze your data and results with respect to the science behind the experiment. As an example, for this experiment analyze the process of recrystallization. Compare the m.pt. & TLC of crude and recrystallised product. Discuss the IR and NMR of 4-Bromoacetanilide and compare them to the spectra of starting materials. Questions : Answer the following questions. Be as complete as possible, and always explain your reasoning.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

1. Which of the following solvent pairs could be used in a solvent pair recrystallization (in general, not for this specific reaction)? For those selected, briefly explain why. For those not selected, briefly explain why not. a) Ethyl acetate and hexane b) Water and diethyl ether c) Water and ethanol d) acetone and water e) ethanol and methanol 2. Would toluene be suitable for a single solvent recrystallization of 4-bromoacetanilide? Why or why not? Please be specific in your explanation (hint: your explanation should focus on polarity of all relevant compounds and solvents). 3. Refer to the FT-IR spectrum, obtained in lab, of your recrystallized product. Please assign specific absorption band frequencies (in cm -1 , from peak picking on the spectrum) to the following functional groups in 4-bromoacetanilide. a) Aromatic C–H stretch b) Amide N–H stretch c) Amide C=O stretch Include a printout of your IR spectrum with your lab report. 4. The solubility of compound “X” in ethanol is 0.80 g per 100 ml at 0 degreeC and 5.00 g per 100 ml at 78 degreeC. What is the minimum amount of ethanol needed to recrystallize a 12.00 g sample of compound “X”? How much would be lost in the recrystallization, that is, would remain in the cold solvent? 5. Below is a 1 H NMR spectrum, and each peak is labeled with a letter. Compare this spectrum to the spectrum of your recrystallized product. a) Is it similar to your spectrum or not? What are the differences, if any? Attach the recorded NMR spectrum here.( answer this part only if you recorded the spectrum! ). b) Explain why this spectrum provides unambiguous evidence that the bromination of acetanilide gave exclusively para -(or 4-)substitution. c) Assign each peak to proton(s) in the structure, and label the structure below accordingly.

Write two questions: Write two questions that come to your mind as you deeply think about the lab and the theory behind it. These need to be your own questions and not some random questions found online. You don’t need to worry about the answers. These questions would usually be “HOW” or “WHY” questions instead of “WHAT” questions and can’t be answered as yes or no. Works Cited : Full references for the experimental procedure(s) in the appropriate format. Include references for any relevant physical properties that were not included in the lab textbook.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version