Lab Manual Organic Analytical Chemistry

ORGANIC ANALYTICAL CHEMISTRY Laboratory Guide This module provides guidelines for safety, Laboratory Report and note book. It’s also providing students with Laboratory manual for subject of Organic Analytical Chemistry (CLB 10803).

FIRST EDITION 2010

Laboratory Information Before each lab session, you should prepare by reading the lab manual, reference book and summarized it in a jotter book. We expect you to have a good understanding of the purpose, details of the procedure, the use of all chemicals and any significant hazards, and the underlying science of the experiment when you come to lab.

CONTENTS

Preface

i

Laboratory safety Guidelines

ii

Safety Declaration Form

vi

Chemistry Laboratory Report Guidelines

vii

Laboratory Notes Books Guidelines

x

Experiment 1

Saponification Reaction reaction of Fat: Soap Production

1

2

Analysis of Food Colour

4

3

Determination of Benzoic acid /caffeine in Soft drink

8

4

Organic Synthesis: Formation of Ester.

11

REFERENCES

14

APPENDICES

15

PREFACE

This manual provides laboratory guidelines, safety declaration form, Chemistry Lab Report guidelines and Laboratory manual for subject of Organic Analytical Chemistry (CLB 10803). The primary purpose of this manual is to compile all necessary information regarding laboratory component in one manual. The manual contains four parts. Part 1 provides a description of laboratory quidelines and safety declaration form. It is compulsory for student to understand all those guidelines and submit safety declaration for recording purposes. Part 2 is laboratory report guidelines containing all requirements such as format and arrangement in order to produce good quality of laboratory report. Part 3 is guidelines for preparation of laboratory notes book. Part 4 is compilation of laboratory manual that will provide student practical guidelines in Organic Analytical Chemistry.

There may be shortcomings which we had overlooked but hopefully these should not hinder the process of enhancing laboratory skill.

Mohd Zulkhairi Abdul Rahim Nor Nadiah Mohamad Yusof

PART 1 LABORATORY SAFETY GUIDELINES General Guidelines 1. Conduct yourself in a responsible manner at all times in the laboratory. 2. Be familiar with your lab assignment before you come to the lab. Follow all written and verbal instructions carefully. If you do not understand a direction or part of a procedure, ask the instructor before proceeding. 3. No student may work in laboratory alone. The lab instructor or co-coordinator grant exceptions on a case by case basis. 4. When first entering a laboratory, do not touch any equipment, chemicals or other materials in the laboratory area until you are instructed to do so. 5. Do not eat, drink beverages or chew gum in the laboratory. Do not use laboratory glassware as containers for food or beverages. 6. Smoking is not allowed in any indoor area. 7. No music allowed in the laboratory. Radio (including walkman) and other entertainment devices are not permitted. 8. No cellular phone is allowed in this laboratory. 9. Perform only those experiments authorized by the instructor. Never do anything in the laboratory that is not called for the laboratory procedures or by your instructor. Carefully follow all instructions, both written and oral. Unauthorized experiments are prohibited. 10. Observe good housekeeping practices. Work areas should be kept clean and tidy at all times. 11. Horseplay, practical jokes, and pranks are dangerous and prohibited. 12. Always work in a well-ventilated area. 13. Bring only your laboratory instructions, worksheets and report to the work area. Other materials (books, purses, backpacks, etc) should be stored in the cabinet. 14. Know the locations and operation procedures of all safety equipment including the first aid kit, eyewash station, safety shower, spill kit and fire extinguisher. 15. Be alert and proceed with caution at all times in the laboratory. Notify the instructor immediately of any unsafe condition you observe. 16. Label and equipment instructions must be read carefully before use. Set up and use the prescribed apparatus as directed in the laboratory instructions provided by your instructor. 17. Experiments must be personally monitored at all times. You will be assigned a laboratory station at which to work. Do not wander around the room, distract other students or interfere with laboratory experiments or others. 18. Write your name and equipment use every time you come in to the laboratory in the log book. 19. Defeating safety devices or using equipment in a manner other than that which is intended will be grounds for dismissal from the lab.

Clothing 1. Safety goggles and safety jacket must be worn whenever you work in lab. 2. Gloves should be worn whenever you use chemicals that cause skin irritations or need to handle hot equipment. 3. Mask should be worn every time you prepare the chemicals. 4. Safety shoes and hard hat should be worn at all times while in the laboratory. 5. Contact lenses should not be worn in the laboratory unless you have permission from your instructor. 6. Dress properly during a laboratory activity. 7. Long hair, dangling jewelry and loose or baggy clothing are a hazard in the laboratory. Long hair must be tied back and dangling jewelry and loose or baggy clothing must be secured. 8. Sandal, open-toed shoes, high heels or shoes with holes in the sols will not be worn in the lab. 9. Short and skirts are not permitted. 10. Instructor and laboratory assistant have a right dismiss to you from the laboratory if they found that you are not wearing proper safety clothing. Handling Chemicals 1. Treat chemicals with respect and understand the chemicals you are using with Material Safety Data Sheet (MSDS). The MSDS are available in the analytical room. 2. All chemicals in the laboratory are to be considered dangerous. Do not touch, taste or smell any chemical unless specifically instructed to do so. 3. Check the label on chemical bottles before removing any of the contents. Take only much chemical are you need. Smaller amounts often work better than larger amounts. 4. Label all containers and massing papers holding dry chemicals. 5. Never return unused chemicals to their original containers. 6. Never use mouth suction to fill a pipette. Use pipette bulb or pipette filler. 7. Acids must be handled with extreme care. Always add acids slowly to water, with slow stirring and swirling, being careful of the heat produced, particularly with sulfuric acid. 8. Handle flammable hazardous liquid over a pan to contain spills. Never dispense flammable liquids anywhere near a flame or source of heat. 9. Never take chemicals or other materials from the laboratory area. 10. Take good care when transferring acids and other chemicals from one part of the laboratory to another. Hold them securely and in the method demonstrated by the instructor as you walk. 11. All wastes generated during the course of an experiment must be disposed of according to the lab instructor’s directions. 12. Never mix chemicals in sink drains. 13. Sinks are to be used only for water and those solutions designated by the instructor.

14. Solid chemicals, metals, matches, filter paper, and all other insoluble materials are to be disposed of in the proper waste containers, not in the sink. 15. Checks the label of all waste containers twice before adding your chemicals waste to the container. 16. Cracked or broken glass should be placed in the special container for “broken glass”. 17. Keep hands away from your face, eyes, mouth and body while using chemicals. Wash your hands with soap and water after performing all experiments. Personal Hygiene 1. Wash hands before leaving the lab and before eating. 2. Gloves should be removed before leaving the lab, using telephones, or entering common areas Accidents and Injuries 1. Report any accidents (spill, breakage, etc) or injury (cut, burn, etc) to the instructor immediately, no matter how trivial it may appear. 2. If you or your lab partners are hurt, immediately tell to the instructor. 3. If a chemical should splash in your eye(s), immediately flush with running water from the eyewash station for at least 20 minutes. Notify the instructor immediately. 4. Spills should be cleaned up immediately. Handling Glassware and Equipment 1. Inserting and removing glass tubing from rubber stopper can be dangerous. Always lubricate glassware (tubing, thistle tubes, thermometer, etc) before attempting to insert it in a stopper. Always protect your hands with tower or cotton gloves when inserting glass tubing into, or removing it from a rubber stopper. 2. When removing an electrical plug from its socket, grasp the plug, not the electrical cord. 3. Hands must be completely dry before touching an electrical switch, plug or outlet. 4. Examine glassware before each use. Never use chipped or cracked glassware. 5. Never use dirty glassware. 6. Do not immerse hot glassware in cold water; it may shatter. 7. Report damaged electrical equipment immediately. Look for things such as frayed cords, exposed wires and loose connections. Do not use damaged electrical equipment. 8. If you do not understand how to use a piece of equipment, ask the instructor for help. 9. Be careful when lifting heavy objects. Lift comfortably, avoid unnecessary bending, twisting, reaching out, and excessive weights, lift gradually and keep in good physical shape. 10. Do not transfer a glassware form one laboratory to another without permission from instructor.

Heating Substances

1. Do not operate a hot plate by yourself. Take care that hair, clothing, and hands are a safe distance from the hot plate at all times. Use of hot plate is only allowed in the presence of the teacher. 2. Heated glassware remains very hot for a long time. They should be set aside in a designated place to cool, and picked up with caution. Use tongs or heat protective gloves if necessary. 3. Never look into a container that is being heated. 4. Do not place hot apparatus directly on the laboratory desk. Always use an insulated pad. Allow plenty of time for hot apparatus to cool before touching it. 5. If leaving a lab unattended, turn off all ignition sources and lock the doors.

Ended the Experiments 9. At the end of the laboratory sessions, you should; ⇒ Shut-off main gas outlet ⇒ Turn-off the water inlet ⇒ Desk top, floor area and sink are clean ⇒ All equipment is cool, clean and arranged 9. All equipment use should be flushed using deionized water.

SAFETY DECLARATION FORM The Dean/Head of Campus Universiti Kuala Lumpur Malaysian Institute of Chemical and Bioengineering Technology Lot 1988, Vendor City Industrial Area Taboh Naning, 78000 Alor Gajah Malacca Dear Sir, SAFETY DECLARATION I ………………………………..…………………………………………………………. ID No ………………………. declare that I have read and understood the safety rules and regulations in UniKL MICET. I hereby agree to abide by all the rules and regulations stated in the safety guidelines.

9. I hereby understood the contents and will disciplinary action will be taken against me, if I do not abide by the stated rules.

9. I am fully responsible for all my actions during laboratory sessions.

Thank you. Yours faithfully,

………………………………. Name: Matrix No: Subject: Date:

PART 2 CHEMISTRY LAB REPORT FORMAT

You should type your lab report. Make sure that you check your document for any spelling errors. Each lab report is worth 100 points. You should also read the student handbook on the subject of plagiarism. Your data and observations will be similar, but your interpretations should not be written identically. You may not copy another student’s lab report in part or in its entirety. If you are found guilty of this infraction, you and the person from whom you copied will both lose points or shared total marks. In extreme cases or repeated offenses, both students may receive a zero for the lab.

Title Use a separate title page. Include the title of the experiment, YOUR NAME, and the date. Also clearly indicate the name(s) of your lab partner(s). Summary/Abstract (not more than 1 page) It should be written after conclusion of experiment OR project. Its cover briefly about Introduction, Objectives, Methodology, Result & discussion, Conclusion Objectives State the objectives of the experiment or report (point form) Example: The objective of the experiments was ……. Introduction Background to the work / experiment Example: The purpose of this experiment was to identify the present of heavy metal in river water by using Atomic Absorption Spectroscopy (AAS). AAS is …………. Theory / formula used in the experiment. Do not just copy word for word from the lab handout. The introduction should be of 1– 3 pages.

Materials List the chemicals and equipment needed to perform the experiment. Procedure Write the procedure in chronological order. Again, DO NOT COPY DIRECTLY from the lab handout. Rearrange your procedure become a passive sentence. Example: Prepare 0.5M NaOH solution (from manual) 0.5M NaOH was prepared (your report)

Result & Discussion

Analyze all data qualitative and quantitative. Then transfer finding into Table, Graph, Histogram and Pie chart if necessary. This includes any observations. Make sure that your graphs have titles, labeled axes with units, and legends. You should include the proper units with any numbers, as well as use the proper number of significant figures based upon the lab equipment used. DO NOT place any calculations or data analysis in this section. It may be a good idea to reproduce here any data tables that you completed during the lab. Base on above point, discuss on your findings and relate to your theory and objective of experiment. Example: Table 1: X vs. Y Samples A B C D

X (unit)

Y (unit)

parameter X (unit)

50 45 y = 4.4557x + 0.9714 40 R2 = 0.9893 35 30 25 20 15 10 5 0 0 2 4

6

8

10

12

parameter Y (unit)

Figure 1: Relationship between X and Y Conclusions This is the most important section. Please include the summary of the results and relate in brief the findings / results with the theory. Answer the questions, “What did you learn?”, “Did I accomplish the purpose?”, “How would I improve the experiment next time?”. Recommendation is optional. The conclusion should be one paragraph of 5 – 7 sentences. References Write down any sources such encyclopedia, books, etc. that you used. • • •

as

your

textbook,

the

Internet,

electronic

A list of lab manuals, books, reports, journal, world wide web (www) etc. Arrangement (year, alphabetical order) Author, title, publisher, year, chapter or page number

Example: Smith J.M and Van Hess H.C., Introduction to Chemical Engineering Thermodynamics, McGraw-Hill, New York, 2001, p229 Appendix Here is where you attach any material that you think is pertinent to the lab report such as summary of calculation involved. Also answer any questions here that are in the lab report. You do not have to re-write the questions, but label and number them appropriately.

PART 3

LABORATORY NOTEBOOKS

You are required to use a bound notebook in CLD 10004 Lab to record all primary data and observations. You should prepare your notebook before coming to a lab by writing the title of the experiment on a new numbered page, summarizing relevant information from the lab manual, and starting calculations involving molar masses, etc. Take note of theoretical ideas and special instructions given by your instructor at the start of each experiment. Your notebook should be a complete record of your work in lab. Notes should be able to understand in the future, not just during the current experiment. Good note taking in a lab is a valuable skill that you can learn with a little effort and practice. Guidelines to be followed: 1. Always bring your notebook with you to lab. You will be graded on the completeness of your previous note taking and your preparation for the current experiment. You may use your notebook during a lab quiz. 2. Number the pages sequentially and reserve space at the beginning for a table of contents. 3. Take your notebook during laboratory hours and record all values directly in it – not on loose scraps of paper. 4. Specify each measured quantity by name and include the units. 5. If you make a mistake in your notebook, simply draw a solid line through the error and write the correction nearby. 6. Tables greatly simplify data entry; they should be set up before coming to lab. 7. Write down all observations if necessary – don’t rely on your memory. 8. Save time by doing trial calculations in your notebook before filling out any report sheets. 9. Save time by making preliminary sketches of graphs (flow Chart) on the ruled lines in your notebook.

PART 4

EXPERIMENT 1

SAPONIFICATION REACTION OF FAT: SOAP PRODUCTION

OBJECTIVE • •

To synthesize a sample of hard soap To test the soap produced

INTRODUCTION

The procedure of making soap involves the basic hydrolysis (saponification) of a fat. Chemically, fats are referred to as triglycerides. They contain ester functional groups. Saponification involves heating fat with an alkaline solution. The alkaline solution hydrolyzes the fat to alcohol and the salt of a long chain carboxylic acid (soap).When common salt is added, the soap precipitates. The soap is washed free of unreacted alkaline solution and molded into bars.

O

O R

C

O

CH

R

C

O

C

Fat

3 NaOH

3R

C

O

Na

CH

HO

CH

HO

CH2

+

Sodium salt of an acid (soap)

O R

CH2

2

+

O

HO

O

CH

2

glycerol

MATERIAL AND METHODS Materials Chemicals: NaOH

50% water/ethanol mixture NaCI Solution

95% ethanol

4 % calcium shloride solution

Fat

Trisodium phospahte

Apparatus: Conical Flasks

Hirsch / Buchner funnel

Beaker

Watch glass

Filter funnel METHODS Preparation of Soap 1.

Prepare a NaOH solution (about 0.25 g sodium hydroxide dissolved in a mixture of 1.0 ml of distilled water and 1.0 ml of 95% ethanol)..

2.

Place about 0.25 g of fat in a 50 ml conical flask and add the prepared sodium hydroxide solution to the flask.

3.

Heat the mixture in a in a bath of 100 oC.

4.

Cover the flask with some aluminum foil to help reduce evaporation. Swirl the Erlenmeyer flask every few minutes. Use tong to do this.

5.

The soap will precipitate from the boiling mixture within 20 minutes.

6.

If you observe that some alcohol and water is evaporating from the flask, you may add up to 0.4 ml of a 50 % water/alcohol mixture to replace the solvent.

7.

Heat the mixture for a maximum time of 25 minutes.

8.

Place 4 ml of NaCI solution in a 15 ml beaker and transfer the saponified mixture from flask to beaker.

9.

Stir the mixture while cooling the beaker in an ice-water bath.

10.

Collect the prepared soap on a Hirsch funnel of ice cold distilled water to remove excess NaOH.

11.

Continue to draw air through the filter for a few minutes to partially dry the product. Test your soap with the procedure below. Analysis of Data

1.

Remove about 0.01 g of soap from the filter paper and placed it in a clean 10 ml graduated cylinder

2.

Add 3 ml of distilled water, close the cylinder with your thumb and shake the mixture vigorously for about 15 sec. After about 30 sec standing, Record your observation. Note down the level of the foam.

3.

Add 5 – 10 drops of 4% calcium chloride solution to the soap mixture from a Pasteur pipette .Shake the mixture for 15 sec and allow it to stand for 30 seconds. Record your observation on the effect of addition the calcium chloride.

4.

Then add 0.5 g of trisodium phosphate and shake the mixture again for 15 seconds. After 30 sec. Again observe and record the result.

APPENDIX

Pre Laboratory Question 1. Give a definition of saponification 2. Explain how soap can function as “dirt remover”. 3. Synthetic detergent functions in the same way as soaps. Give the advantages of synthetic detergent over soaps.

Post Laboratory Question 1. Reaction of fat with NaOH will produced long chain carboxylic acid (soap) in form of Bar. What would be happen if sodium Hydroxide (NaOH) is replaced by Potassium hydroxide (KOH).

EXPERIMENT 2

ANALYSIS OF FOOD COLOUR

OBJECTIVE (1) To determine λmax of Colourant (wavelength scan) (2) To prepare a serial dilution and generate a standard calibration graph for sample quantitation (photometric scan)

INTRODUCTION

Food coloring (colouring) is any substance that is added to food or drink to change its color. . Synthetic Food Colours, also known as Artificial Food Colours, are manufactured chemically and are the most commonly used dyes in the food, pharmaceutical and cosmetic industries. Besides that , a growing number of natural food dyes are being commercially produced, partly due to consumer concerns surrounding synthetic dyes. Some examples include Caramel coloring (E150), made from caramelized sugar, used in cola products and also in cosmetics.Annatto (E160b), a reddish-orange dye made from the seed of the Achiote A green dye made from chlorella algae (chlorophyll, E140) and etc. All those colourant can be analyze by using an ultraviolet/visible spectrophotometer. Figure 1.0 below gives a schematic diagram of a double beam spectrophotometer. Instruments for measuring the absorption of U.V. or visible radiation are made up of the following components; Sources (UV and visible), Wavelength selector (monochromator), Sample containers, Detector, Signal processor and readout

Figure 11.1

Schematic diagram of double beam UV – Vis spectrophotometer

When a beam of parallel radiation passes through a layer of solution of thickness, b (cm) and a concentration, C (moles per liter) of an absorbing species, absorption of radiation occurs. The transmittance (T) of the solution is the fraction of incident radiation transmitted by the solution. Transmittance is often expressed as a percentage. The absorbance (A) of a solution is defined as the negative log of the transmittance (T) of the solution. The absorbance is directly proportional to the path length of the radiation through the solution and the concentration of the absorbing species.

A=εbc Where;

A = absorbance (no unit) ε

= molar absorptivity coefficient (M-1 cm-1)

b

= pathlength (cm)

c = concentration (M or mol/L)

This relationship between absorbance, A and ε bc is known as Beer’s Law. Beer’s Law is successful in describing the absorption behavior of dilute solutions only. At high concentrations, absorbance of the solution does not obey Beer’s Law and is no longer proportional to C. In this experiment you are going to conduct two main applications which are wavelength scanning and photometric scanning.

MATERIALS AND METHODS Materials Chemicals 100 ppm colorant stock (100 ml), Unknown (two), Distilled water Apparatus Perkin – Elmer UV/Vis Spectrophotometer Lambda EZ210, Sample cuvettes, path length 1 cm, Volumetric flask 50 ml (five) , Pipette 5 ml, 10 ml and 25 ml (one each),Rubber bulb (three),Beaker 100 ml (one),Graduated cylinder 50 ml (one),Dropper (one),Labeling sticker,Tissue paper Methods 1.

Prepare serial dilutions (5 ppm, 15 ppm, 25 ppm, 35 ppm and 45 ppm) in 50 ml volumetric flask from the 100 ppm carmoisine stock.

2.

After preparing the serial dilutions, your instructor will brief on the standard operating procedure of Perkin – Elmer UV/Vis Spectrophotometer Lambda EZ210.

3.

Fill a cuvette with 45 ppm dilution and another cuvette with blank solution; insert them in the sample compartment. Wipe clean the sides of the cuvettes and remember not to touch on the clear surface. Do the wavelengths scan and obtain the λmax. Record your data..

4.

For photometric scan, fill the cuvette as step no 3 but use the serial dilution prepared and scan one by one. Record the absorbance readings and look at the standard calibration graph produced.

5.

Also determine the concentrations of Unknown #1 and Unknown #2.

Analysis of Data The purpose of wavelength scan is to determine at what wavelength the carmoisine able to absorb in the range of 200 nm to 700 nm. From spectrum obtain, please identify λmax . The purpose of photometric scan is to determine the concentration (single component) of an unknown sample, after generating a working 'standard curve' from a series of known standards (known concentration). Record the absorbance readings for a series of prepared dilution generate standards calibration curve and identify concentration of unknowns. All calculation must show in detail.

Pre Laboratory Question 1. State the Beer’s lambert law.

2. What is the volume needed to prepare a 50 ppm of carmoisine from a 100 ppm of carmoisine in 100 ml volumetric flask?

Post Laboratory Question 1. Why we need to wipe the sides of the cuvette clear surface?

2. Describe the function of wavelength scanning and photometric scanning.

EXPERIMENT 3

Determination of Benzioc acid / Caffeine in Soft drink

Objective : 1. To Identify the present of Benzoic acid/ Caffeine in soft drink sample 2. To determine amount of caffeine in soft drink sample.

Introduction:

High Performance Liquid Chromatography (HPLC) is a chemistry based tool for quantifying and analyzing mixtures of chemical compounds. It can be used to separate compounds that are dissolved in solution. HPLC instruments consist of a reservoir of mobile phase, a pump, an injector, a separation column, and a detector. Compounds are separated by injecting a plug of the sample mixture onto the column. The different components in the mixture pass through the column at different rates due to differences in their partitioning behavior between the mobile liquid phase and the stationary phase.

The area of this peak (in relation to the area of other peaks) is proportional to the concentration of that particular species in the sample. The identity can also be found by comparing the sample peaks to standards. Identical substances (peaks) will have identical retention times.

MATERIALS AND METHODS

Materials: Isocratic HPLC system with UV detector, C18 column, Vacuum, Funnel, 0.45 µm filter paper 0.45 µm filter syringe,100 µL syringe,60 mL syringe,Volumetric flask Chemicals Caffeine 1000 ppm standard (stock solution), Methanol (HPLC grade), Double distilled water (filtered with 0.45 µm filter paper), Soft drink sample

Methods: 1. Preparation of Benzoic acid/ caffeine standards ⇒ Prepare standard caffeine samples of 20 ppm, 40 ppm, 60 ppm, 80 ppm and 100 ppm by diluting portions of the 1000 ppm solution with distilled water. 2. Preparation of soda samples ⇒ Obtain a soft drink sample. ⇒ Degas the sample by placing it in a vacuum flask and connecting the flask to a vacuum pump or water aspirator. Leave it under vacuum until no more bubbles appear in the soda sample. (If no vacuum is available, allow the soda to stand open overnight.) ⇒ Filter the degassed soda through #42 filter paper. 3. After preparing the serial dilution and sample, your instructor will brief on standard operating procedure of HPLC. Analysis of data 1.

Use standard benzoic acid /caffeine retention time to identify the benzoic acid/caffeine peak and then record their retention time.

2.

By using above information, clarify and justify the present of benzoic acid/caffeine in the soda sample.

3.

Record different concentration of standards peaks area and construct a standard calibration curve (concentration vs peak area).

4.

Measure the caffeine peak in the soda sample chromatograph, and use standard calibration curve (concentration vs peak area) to determine the concentration of Benzoic acid/ caffeine in the soda sample.

Note: All raw data must be record in table form.

Pre – Lab Questions: 1. Briefly explain how HPLC is used as a separation technique. 2. What is the purpose of the mobile phase? Of the stationary phase? 3. What is the purpose of the caffeine standards? Post – Lab Questions: 1. Why does the syringe have to be carefully rinsed before each use? 2. Retention of caffeine in standards. How could you be identify a peak in the soda was caffeine and not another substance by using retention time?

EXPERIMENT 4

ORGANIC SYNTHESIS: FORMATION OF ESTER

OBJECTIVE •

To synthesis ethyl acetate (ethyl ethanoate)

INTRODUCTION

Chemist use organic synthesis to make larger amounts of useful natural compounds and to invent totally new compounds. Depending on the choice of R’ and R, we have a variety of the final ester, R’COOR. Small chain side groups give very aromatic compound, while long – chain side groups form waxy compounds.

Carboxylic acid

alcohol

ester

water

The reaction of a carboxylic acid with an alcohol to produce an ester plus water is known as the Fisher esterification reaction. A mineral acid, usually sulfuric acid is used as a catalyst. MATERIALS AND METHODS Chemical: Ethanol, Glacial acetic acid, Conc. sulfuric acid, 30% Sodium carbonate solution, Calcium chloride, Granular anhydrous Calcium chloride, anti-bumping granules. Apparatus: Round bottom flask, Water condenser, retort stand, separating funnel

Methods 1. Set – up a reflux system. 2. Mix 50 ml of 95% ethanol and 50 ml of glacial acetic acid thoroughly in a 250 ml round – bottomed flask. Add slowly with cooling and shaking 10 ml of concentrated H2SO4. Ensure that the mixture is homogenous, and then fit the flask with a reflux water – condenser and boil the mixture gently for 10 minutes. Cool the flask and its content. 3. Rearrange the position of the condenser for distillation set –up. 4. Put a few boiling chips in the flask. A filter flask, whose side arm is joined to a rubber tube leading over the edge of laboratory bench, is used as a receiver. Ethyl acetate is highly flammable. Therefore any vapors should be conducted off the table towards the floor. Distlled off about 2/3 of the mixture. 5. Transfer the distillate to a separating funnel and add about 25 ml of 30 % Na2CO3 solution. Stopper the funnel, invert it and shake it, opening the stopcock from time to time. Allow the two layers to separate. Carefully run off and reject the lower layer, ensuring that the sodium carbonate is removed as completely as possible. 6. Prepare a solution of 25 g of calcium chloride in 25 ml of water. Add if to crude ethyl acetate in the funnel. Shake vigorously. Allow the mixture to separate. Run off the lower aqueous as completely as possible. 7. Run the ethyl acetate into a small conical flask. Add a few lumps of granular anhydrous calcium chloride. Shake occasionally until the liquid is clear. 8. Decant the liquid some anti bumping granules. Arrange for distillation (with a 0 – 100 oC thermometer in the apparatus). Pre – weight the receiving flask. The distilling flask should be placed in cold water bath, which is gradually heated. 9. The ether that is always formed in this reaction will distill off at 35 – 45 oC and may be discarded. Continue to heat and collect the fraction that boils between 74 oC and 79 oC. 10. Weight your product and calculate the percentage yield. 11. Run FTIR of your product and characterize it smell. 12. Inject substrate and product into Gas chromatography.

Analysis 1. From mass of acid, determine the percent yield of your final product (Show all calculation in detail) 2. Interpret the FTIR of this compound. Identify the principles peaks. 3. Interpret Gas chromatography result.

Appendix Pre – Lab Question 1. Reaction of acetic acid with ethanol to produce will produce ethyl ethanoate and water. Based on that the reaction, how many grams of ethyl ethanoate would be produced if 50 ml of ethanol were react with 50 ml acetic acid? (given 1.06 g/ml and

ethyl acetate:

ethanol:

0.8 g/ml and

acetic acid

:

0.9g/ml). Calculate the percentage yield if 50.0 g of ethyl

ethanoate was obtained from the experiment.

Post – Lab Question 1. What are percent yields? How this can be improves? 2. Based on result above, does the FTIR show any contaminant from initial reactants? Explain.

REFERENCE 1. Francis A Carey, Organic Chemistry, 7th Edition, McGraw Hill ISBN : 0073311847 / 9780073311845 2. T.W. Graham Solomon,Organic Chemistry, 8th Edition, Wiley QD253.2.S65 2004 3. Douglas A. Skoog, Donald M. West and F. James Holler, Fundamentals of Analytical Chemistry, 8th ed., Saunders College Publishing, 1997. QD75.22.F86 2003 4. Mohan, Jag, Organic Analytical Chemistry: Theory and Practice, Alpha Science International, Ltd, 2004 ISBN :0849339529 / 9780849339523 5. Mohan,Jag, Organic Spectroscopy: Principles and Applications, Alpha Science International, Ltd. ISBN :0849339529 / 9780849339523

APPENDIXS

Mass 1 lbm = 0.453592 kg 1 ton = 2000 lbm 1 kg = 2.20462 lbm

Force 1 lbf = 4.448222 N 1N = 0.224809 lbf = 1 kg.m/s2

Volume 1 ft3 = 0.028317 m3 1 L = 0.001 m3 1 m3 = 35.32 ft3 1 cm3 = 0.06102 in3 1 gal =0.0037854 m3 1 gal/min = 6.31 x 105 m3/s

Density 1kg /m3 = 0.062428 lbm/ ft3

Pressure 1 pascal (Pa) = 1 N/m2 1 atm = 760 mmHg = 760 torr 1 atm = 101.325 KPa

Table 1.0 Characteristic Infrared Absorption frequencies Bond

Compound Type Alkanes

C-H CH3 Umbrella Deformation C-H Alkenes Aromatic Rings C-H Phenyl Ring Substitution Bands Phenyl Ring Substitution Overtones

Frequency range, cm-1 2960-2850(s) stretch 1470-1350(v) scissoring and bending 1380(m-w) - Doublet - isopropyl, tbutyl 3080-3020(m) stretch 1000-675(s) bend 3100-3000(m) stretch 870-675(s) bend 2000-1600(w) - fingerprint region 3333-3267(s) stretch

C-H Alkynes 700-610(b) bend C=C Alkenes

1680-1640(m,w)) stretch

C C Alkynes

2260-2100(w,sh) stretch

C=C Aromatic Rings

1600, 1500(w) stretch

C-O Alcohols, Ethers, Carboxylic acids, Esters 1260-1000(s) stretch C=O

Aldehydes, Ketones, Carboxylic acids, Esters

1760-1670(s) stretch

Monomeric -- Alcohols, Phenols

3640-3160(s,br) stretch

O-H Hydrogen-bonded -- Alcohols, Phenols Carboxylic acids N-H Amines

3600-3200(b) stretch 3000-2500(b) stretch 3500-3300(m) stretch 1650-1580 (m) bend

C-N Amines

1340-1020(m) stretch

C N Nitriles

2260-2220(v) stretch

NO2 Nitro Compounds

1660-1500(s) asymmetrical stretch 1390-1260(s) symmetrical stretch

v - variable, m - medium, s - strong, br - broad, w - weak

∼THIS IS THE END OF THE LABORATORY MANUAL ~