PART 1: RECRYSTALLIZATION OF AN ORGANIC SOLID

Size: px
Start display at page:

Download "PART 1: RECRYSTALLIZATION OF AN ORGANIC SOLID"

Transcription

1 EXPERIMENT 2 PART 1: RECRYSTALLIZATION OF AN ORGANIC SOLID THEORY Recrystallization is a purification technique that is very frequently used for organic compounds. When solid reaction products are isolated, they are seldom "pure" but are usually contaminated with small amounts of impurities such as reaction by-products, unreacted starting material, etc.. The process of recrystallization is used to "purify", or separate, the desired compound from the impurities. If you want to dissolve an ionic (salt-type) or very polar material, you use a polar, ionizing solvent such as water. If you want to dissolve a non-polar material (many organic compounds) you use a non- or relatively non-polar (organic) solvent. For intermediate cases where the material is moderately polar, water and/or organic solvents such as the alcohols, ethers, etc., may be suitable. In most cases the solubility of solids in liquids increases with increasing temperature. In crystallizations (or recrystallizations) we take advantage of this phenomenon by dissolving the solid in the minimum amount of hot solvent, rapidly filtering the hot solution to remove any insoluble impurities, and then allowing the filtrate to cool slowly and undisturbed so that large, well-formed crystals are obtained with the minimum number of imperfections and minimum surface area to trap and hold impurities. After cooling slowly to near room temperature, the material is chilled, in ice, to get maximum recovery of crystals. The solid is then collected by suction filtration and dried. If desired or necessary, the filtrate can be concentrated to give a second crop of crystals. DEFINITIONS AND TERMS: Pure: All molecules of the sample are identical (an impossible goal!) Impurities: Other undesired compounds present in the sample of desired compound. The impurities are usually unreacted starting materials or by-products from the reaction. Solvent: A liquid, either a single compound or a mixture, which will dissolve the solid to be purified. Solute: The material (impure) that is dissolved in the solvent.

2 - 2 - Mother liquor: The solution remaining after the "pure" product has been removed by suction filtration. This solution contains some desired product that did not crystallize but now has a higher proportion of impurities. Saturated solution: A solution that has the maximum possible concentration of solute that can exist at equilibrium with the solid substance, at a given temperature. Solubility: The concentration (in g/100 ml, mol L -1, etc.) of solute in a saturated solution. Solubility generally increases with increasing temperature, though there are exceptions. Crystallization: The process of cooling, without the loss of solvent, a hot, nearly saturated solution of a compound so that as the temperature falls, the solubility of the solute decreases and crystalline material is deposited from the solution. These crystals, that can be collected by filtration, will be of higher purity than the starting solute. Recrystallization: Repetition of the above process using the crystalline product that came out of solution, to achieve further purification. GENERAL Unless an impurity is very insoluble in the chosen solvent, it may remain in solution through the whole process. Since it is only a minor component, there may not be enough of it to form a saturated solution, even after cooling. A very soluble component in small proportions will certainly not come out of solution on cooling. The crystallized sample will only contain any of the soluble impurities if any remaining mother liquor evaporates from the crystals at the end of the cold suction filtration step. The purified product will probably still contain some of the impurities, but at a much lower level. 1. Solvent: The choice of a solvent is an art! In this course, you will be told what solvents to use. In general, one follows the adage "like dissolves like" (e.g. polar solids tend to dissolve in polar solvents, non-polar solids in non-polar solvents), but the choice of a good solvent is much more complex. Some factors to consider for a solvent follow: It must have a reasonably low boiling point, to aid in easy removal from the isolated "pure" product. There should be a wide range between the boiling point of the solvent and the melting point of the product. The solvent should boil well below the melting point of the solute, otherwise the product will not crystallize but separate as an oil as the saturated solution cools. The solvent must not react with the product and must be able to dissolve the product when hot, but not dissolve much of it at 0 C. Frequently, mixtures of miscible solvents (e.g. ethanol and water) are employed. If a solid is very soluble in hot ethanol and still rather soluble in cold ethanol, most of the desired product will remain in solution on cooling and yields will be low. If this solid is insoluble in water, an ethanol-water mixture can be found that has the

3 - 3 - desired properties, e.g. high solute solubility when hot, low solubility when cold. Mixed solvents are used in two ways: Either the mixture is made up before the crystallization then used as if it were a pure solvent, or, more frequently, the solute is dissolved in the hot solvent in which it is very soluble and then the second solvent is added, slowly, to the hot solution (after hot filtration) to force the solute out of solution. This process requires skill; check with your instructor the first time it is attempted. 2. Dissolving the solute: The solute is placed in an Erlenmeyer flask, boiling stones are added and the MINIMUM amount of boiling solvent is added to dissolve the sample. The solution is boiled and if all the solid does not dissolve, more solvent is added and the solution boiled again. This procedure is continued carefully until all the solute is dissolved or until no more remaining solid will dissolve. (The remaining solid could be insoluble impurities.) Use of too much solvent will cause the desired product to remain in solution on cooling, rather than crystallizing. Use of too little solvent will cause premature crystallization in the flask or in the filter paper during the hot gravity filtration. When all of the solute has been dissolved, a few ml of extra solvent (maybe 10% of the solution volume) should be added to compensate for solvent loss that occurs during subsequent heating/boiling. 3. Charcoal: If the solution (solvent + solute) is coloured by high molecular weight impurities, activated charcoal may be added, as it tends to adsorb these impurities and thus remove the colour. The charcoal is removed during the hot gravity filtration. Charcoal particles will cause boiling solvents to foam, so remove the solution from the heat and when the boiling stops (~20 30 seconds), add the charcoal (~0.2g). The solution should be boiled gently for a minute or two before filtering. 4. Hot filtration: This procedure removes insoluble impurities from the solution. Hot gravity filtration employs a fluted #4 (615) filter paper in a glass funnel. The funnel and flask are preheated on the steam bath and are supported in or on the steam bath (in the bath for large flasks or high boiling solvents, on the bath for small flasks or low boiling solvents) during the filtration to avoid cooling the solution and thereby preventing premature crystallization in the filter paper, funnel or flask. When the solvent is non-aqueous, it is advisable to dry the glass funnel, with a towel, just before use. The filter paper should also be kept as full as possible during the filtration by continually adding hot (boiling) solution. This filtration is not done with suction as the vacuum will cause the hot solution, which is to be retained, to boil vigorously which could cause loss of or contamination of the product. 5. Cooling: The hot filtered solution is cooled to cause the crystallization of the product. First the solution is cooled slowly to room temperature and then chilled in an ice bath for 10 15

4 - 4 - minutes. Allowing the solution to stand undisturbed, so that slow steady cooling occurs, allows the formation of large crystals, while swirling the solution causes more rapid cooling, resulting in smaller crystals. 6. Ice bath: For efficient cooling of a flask and its contents, an ice bath should contain enough water to form a slurry of ice cold (0 C) water and ice around the flask. Using only ice results in inefficient cooling as the flask is cooled only at the points of ice contact rather than over the whole immersed surface. 7. Suction filtration: This is used to collect the purified crystals on a flat filter paper (#5 or 610, hardened) in a Buchner funnel placed on a thick walled suction flask that is connected to a water aspirator. The water aspirator, when turned on full, achieves a partial vacuum that pulls the solvent from the crystals quickly. Before pouring the cold crystals/solvent mixture into the funnel, the filter paper, wetted with solvent (read note 8 and/or consult a demonstrator), is sealed onto the funnel by turning on the vacuum. The crystals/solvent mixture should be swirled and poured carefully, but quickly, into the funnel. The "mother liquor" may be used to rinse any remaining crystals out of the crystallizing flask and it may be used to obtain a second crop of product so the suction flask must be clean. It is a good practice to clean out the suction flask before each filtration. If necessary, pressing the crystals with a clean spatula will speed up removal of solvent. 8. Sealing the filter paper: Before the solution is filtered, the filter paper must be sealed onto the funnel. The paper must be sealed by pouring some of the solvent through the paper, placed in the funnel, and applying the suction so that the paper is sealed. If the solvent used is water, the paper will easily be sealed, but if the solvent used is a more volatile organic solvent, such as ethanol, problems can arise. If the solvent used is ethanol, the paper may not seal very easily because the ethanol may evaporate from the paper very rapidly and the seal will be broken. If filtration is attempted after the seal has been broken, the crystals will be sucked through the funnel and will be lost. To prevent this, one of the following methods can be employed. Either Pour a little water through the funnel, apply the suction to seal the paper and then pour some ethanol through to wash the water from the paper. The filtration must then be performed fairly rapidly, before the paper becomes unsealed. Also note that if all of the water was not rinsed from the paper, the paper will likely become clogged with product as the solution is filtered and the filtration will proceed slowly. Or

5 - 5 - Pour a little cold ethanol through the paper, apply the suction until all of the ethanol has been pulled through the paper (and the paper is sealed) and immediately filter your crystals before the paper can become unsealed. 9. Washing crystals: Washing is necessary to remove mother liquor from the solid product after suction filtration. Washing is best done with small volumes of fresh, ice-cold crystallization solvent, but note that this will cause some loss of crystals as the product will still have some solubility in the cold solvent. It is useless simply to pour solvent through the crystals under suction as the solvent goes through so quickly that little is achieved. The proper procedure is to break the vacuum either at the aspirator or by lifting the funnel, add the ice-cold, fresh solvent to the crystals in the funnel, carefully swirl so the solvent mixes with the crystals but does not disturb the filter paper, then reapply the vacuum to remove the washing solvent. Consult an instructor before washing crystals. NOTE: Never turn off the aspirator without breaking the vacuum or water may suck back through the aspirator into the suction flask. 10. Product: The product crystals can be dried on the Buchner funnel by suction for minutes if the solvent is volatile. If not, it is best to scrape the crystals onto a clean dry watch glass and allow them to dry in your locker over the week. Note: Some solid products will sublime if left open in this way, so if you are unsure, check with an instructor. When the crystals are dry, weights and melting points can be determined.

6 - 6 - RECRYSTALLIZATION OF TRIMYRISTIN The crude trimyristin (from lab 1) should be in your locker in a 250 ml round bottom flask. Before proceeding, make sure that you know the mass of the crude product from experiment one. Boil a portion of absolute ethanol. To the crude sample, add hot absolute ethanol (about ml) and heat the solution to boiling (boiling stones!) using a steam bath. If the crude lipid is not completely dissolved, add more ethanol, a few ml at a time, until no more solid will dissolve. (The amount of ethanol needed will vary, depending on the yield of crude material you have obtained, but you should not need more than 15 ml). Remove from the steam, let stand for seconds, then slowly add 0.2 g activated charcoal. Boil the solution gently for 2 minutes on the steam bath. Heat your short stemmed funnel on the steam bath while boiling the sample. Filter the hot solution by gravity through a fluted filter paper into a clean dry Erlenmeyer flask (placed on the steam bath to prevent premature cooling and crystallization during filtration). The flask containing the filtered solution should be set aside to cool to room temperature. As the solution cools, a white crystalline solid should form. When crystals are present you may cool the flask quickly (e.g. in an ice bath) to complete the recrystallization. Chill a small sample of absolute ethanol (10-15 ml in a sample vial) for use in the washing step. Set up the apparatus for a suction filtration, using a clean, dry suction flask and a Buchner funnel (#5, hardened filter paper). Before filtration, ensure that the filter paper is sealed using ethanol (See notes 7 & 8 on page 22). Filter the cold solution by suction through the Buchner funnel. Use some ice-cold absolute ethanol to transfer the remaining crystals out of the Erlenmeyer flask into the funnel and wash them with a small volume of ice-cold ethanol. Use a small clean spatula to squeeze excess solvent from the product and allow the aspirator to draw air through the solid for a few minutes. This will have the effect of drying the crystals. Spread the crystals on to a small pre-weighed watch glass and leave them in your locker for a week to complete drying. At this point, proceed to PART 2 of this experiment. After the product has been drying for a week, weigh the product and determine the melting point of the sample. Crush a small sample of trimyristin on a watch glass and place it into a melting point capillary. You should look up the expected melting point to help determine the appropriate power level. Place the capillary in the melting point apparatus and determine the melting range for the sample and add this to the raw data for lab #2. Compare the experimental melting point to the literature value. Comment on the purity of the sample. After the melting point has been measured, transfer the purified trimyristin to sample vial, label it and store it in your locker until it is needed in lab period 10 and 11.

7 - 7 - PART 2: MELTING POINTS THEORY The melting point is the temperature at which the solid and liquid phases of a compound are in equilibrium. The term "melting point" should be more appropriately be referred to as a "melting range" because even for very pure substances, there is a small temperature range between the start and completion of melting. Pure substances will melt over a narrow range (1-3 C). Impure substances tend to melt at a lower temperature and over a broader range. Both the size of the range and the actual melting point are thus useful indicators of the purity of a compound. PROCEDURE Before coming to the lab, look up the expected melting points for trans cinnamic acid and for urea and read appendix 1 for details on the procedure for determining a melting point. Crush a small sample of trans cinnamic acid on a watch glass and place it into a melting point capillary. Repeat this procedure for a small sample of urea. Combine a sample of your crushed cinnamic acid with a sample of crushed urea on a watch glass and thoroughly mix them together. Place this sample into a third capillary. Place all three capillaries in the melting point apparatus and determine the melting ranges for the three samples. You can melt all three samples during one trial, since the melting point device can accommodate up to three samples at one time. In the Discussion section, compare the experimental melting points to the literature values and comment on the purity of the samples. REPORT In the purpose section, explain (briefly) how the recrystallization procedure removes impurities from the sample. Your explanation should explain how impurities are removed by each of the following steps: the use of charcoal, the hot gravity filtration and the cold suction filtration. Calculate the percentage recovery for the recrystallized product and comment on sources of error. Comment on the melting points of the recrystallized sample.

8 - 8 - QUESTIONS (FALL 2010) 1. A sample of benzoic acid contaminated with borax and sand is to be recrystallized. Compound Solubility in 100 C Solubility in 0 C in g / 100 ml in g / 100 ml Benzoic acid Borax Sand insoluble insoluble The sample initially contained 3.0 g of benzoic acid, 1.5 g of Borax and 1.0 g of sand and was treated with 50 ml of boiling water, filtered by gravity and then cooled in ice to obtain a precipitate which was isolated by suction filtration. How much benzoic acid should be formed and will it be pure (in theory)? Use calculations to aid in your explanation. 2. After the suction filtration, the filtrate in the suction flask contains (among other things) some dissolved product, which had failed to crystallize. Could you process this filtrate to obtain a sample of the product? Explain. Would the second crop of crystals be as pure as the first crop? Explain. 3. Why is 2-methyl-2- propanol rarely used as a solvent for recrystallization? (Look up some of it's physical properties such as boiling point, melting point) QUESTIONS (WINTER 2011) 1. A sample of benzoic acid contaminated with NaCl and sand is to be recrystallized. Compound Solubility in 100 C in g / 100 ml Solubility in 0 C in g / 100 ml Benzoic acid NaCl Sand insoluble insoluble The sample initially contained 3.0 g of benzoic acid, 2.0 g of NaCl and 1.0 g of sand and was treated with 50 ml of boiling water, filtered by gravity and then cooled in ice to obtain a precipitate which was isolated by suction filtration. How much benzoic acid should be formed and will it be pure (in theory)? Use calculations to aid in your explanation.

9 You are given a mixture of solids A,B and C. In the solvent you are using, compound A is slightly more soluble than compound B, while C is essentially insoluble. Could you use the technique of recrystallization to obtain a sample of pure A? Explain. 3. During the suction filtration, the recrystallized product is washed with ice cold ethanol. Explain why this washing solution must be ice-cold. Since the recrystallized sample is not soluble in water, why not use ice-cold water as the washing solvent?

Purification by Recrystallization

Purification by Recrystallization Experiment 2 Purification by Recrystallization Objectives 1) To be able to select an appropriate recrystallizing solvent. 2) To separate and purify acetanilide by recrystallization. 3) To compare the melting

More information

Recrystallization Techniques

Recrystallization Techniques Adapted from: Recrystallization Techniques The Purity and Purification of Solids, CHEM 337M Laboratory Manual; Portland State University, Portland, OR, 1995. Prelab Assignment Read Ch. 13 (all) in your

More information

EXPERIMENT 2: Recrystallization and Melting Point

EXPERIMENT 2: Recrystallization and Melting Point Recrystallization (or Crystallization) is a technique used to purify solids. This procedure relies on the fact that solubility increases as temperature increases (you can dissolve more sugar in hot water

More information

Lab #4: Crystallization

Lab #4: Crystallization Name bjectives: - Purify an impure sample of an antibiotic. - Practice the crystallization technique. Lab #4: Crystallization Introduction: The purpose of this experiment is to introduce the technique

More information

Separation of a Mixture In-Class Prelab NAME

Separation of a Mixture In-Class Prelab NAME 1 Separation of a Mixture In-Class Prelab NAME The amounts of sand, salt, and benzoic acid that will dissolve in 100 g of water at different temperatures: Temperature 0 o C 20 o C 40 o C 60 o C 80 o C

More information

Preparation and purification of Acetanilide

Preparation and purification of Acetanilide EXPERIMENT 5 - Preparation of Acetanilide Preparation and purification of Acetanilide Purpose: a) To synthesis acetanilide by reaction of aniline and acetic anhydride. b) To purify acetanilide by crystallization

More information

CHEM 2423 Recrystallization of Benzoic Acid EXPERIMENT 4 - Purification - Recrystallization of Benzoic acid

CHEM 2423 Recrystallization of Benzoic Acid EXPERIMENT 4 - Purification - Recrystallization of Benzoic acid EXPERIMENT 4 - Purification - Recrystallization of Benzoic acid Purpose: a) To purify samples of organic compounds that are solids at room temperature b) To dissociate the impure sample in the minimum

More information

H N 2. Decolorizing carbon O. O Acetanilide

H N 2. Decolorizing carbon O. O Acetanilide Experiment 1: Recrystallization of Acetanilide Reading Assignment Chatpers 2 4 (Glassware, Reagents, & Heating), Chapter 9 (Filtration) Chapters 14 15 (Melting Point & Recrystallization) The purification

More information

Isolation and Purification of Organic Compounds Recrystallization (Expt #3)

Isolation and Purification of Organic Compounds Recrystallization (Expt #3) Isolation and Purification of Organic Compounds Recrystallization (Expt #3) Recrystallization, which relies on equilibria at a solid-liquid interface, occurs when a solid material precipitates from a cooling

More information

CHM 226 Recrystallization of Acetanilide

CHM 226 Recrystallization of Acetanilide Recrystallization is an important method used by chemists to purify solid compounds. Why is purification so important? Well, from a real world perspective, when a chemist conducts a chemical reaction as

More information

Recrystallization Introduction Solubility

Recrystallization Introduction Solubility 1 Recrystallization Introduction Solubility Most compounds are more soluble in a given solvent at higher temperatures. As you can see from the data in the table below, the solubilities in water of salt

More information

Experiment 3: Acid/base Extraction and Separation of Acidic and Neutral Substances

Experiment 3: Acid/base Extraction and Separation of Acidic and Neutral Substances Experiment 3: Acid/base Extraction and Separation of Acidic and Neutral Substances Introduction You will be given a mixture that contains three substances in equal amounts: benzoic acid, 2-naphthol and

More information

Chem 267. Recrystallization Part 1. (revised 7/10)

Chem 267. Recrystallization Part 1. (revised 7/10) Chem 267. Recrystallization Part 1. (revised 7/10) Recrystallization is the most common method for purifying solid compounds. It will be used throughout this course so it is vital that you understand the

More information

Recrystallization PRE-EXPERIMENT ASSIGNMENT

Recrystallization PRE-EXPERIMENT ASSIGNMENT Recrystallization Recrystallization is a very common technique used to purify solids. A material termed impure is a mixture of two or more components, from which only one component is desired. The other

More information

#15 Synthesis and Characterization of Aspirin

#15 Synthesis and Characterization of Aspirin #15 Synthesis and Characterization of Aspirin ne of the simpler organic reactions that can be carried out is the formation of an ester from an acid and an alcohol. This reaction proceeds as follows: R

More information

Professor Kathleen V. Kilway and Robert Clevenger, Department of Chemistry, University of Missouri Kansas City, 2006

Professor Kathleen V. Kilway and Robert Clevenger, Department of Chemistry, University of Missouri Kansas City, 2006 Professor Kathleen V. Kilway and Robert Clevenger, Department of Chemistry, University of Missouri Kansas City, 2006 1. Crystallization J.R. Mohrig, Chapters 3, 14 and 15 C.N. Hammond, 31-40 (lab notebook

More information

Organic Chemistry 253 Experiment #3 Recrystallization 1

Organic Chemistry 253 Experiment #3 Recrystallization 1 Organic hemistry 253 Experiment #3 Recrystallization 1 Blessed are the pure in crystal Merrit DeBartolo 2002 It is possible to purify compounds by recrystallizing them in a solvent in which they are soluble

More information

Organic 211L Recrystallization. Additional Handout. Recrystallize. Why? To separate a compound from impurities.

Organic 211L Recrystallization. Additional Handout. Recrystallize. Why? To separate a compound from impurities. Organic 211L Recrystallization Additional Handout Recrystallize. Why? To separate a compound from impurities. How to recrystallize (generally): Dissolve your solute in the least amount of solvent necessary.

More information

Covalent Bonding - Benzoic Acid from Ethyl Benzoate by Base Hydrolysis

Covalent Bonding - Benzoic Acid from Ethyl Benzoate by Base Hydrolysis EXPERIMENT 2: Introduction ovalent Bonding - Benzoic Acid from Ethyl Benzoate by Base Hydrolysis Ethyl benzoate (boiling point 211-213, melting point -34 ) belongs to a class of compounds called esters.

More information

9. Recrystallization

9. Recrystallization 9. Recrystallization Recrystallization is a very common technique used to purify solids. A material termed impure is a mixture of two or more components, from which only one component is desired. The other

More information

Experiment 9 Chem 276 Fall Semester 2010 Page 1 of 8. Separation of compounds using acid-base extraction

Experiment 9 Chem 276 Fall Semester 2010 Page 1 of 8. Separation of compounds using acid-base extraction Experiment 9 Chem 276 Fall Semester 2010 Page 1 of 8 Introduction: Separation of compounds using acid-base extraction Organic compounds are generally insoluble in water. Instead, they are soluble in organic

More information

Experiment 8 Synthesis of Aspirin

Experiment 8 Synthesis of Aspirin Experiment 8 Synthesis of Aspirin Aspirin is an effective analgesic (pain reliever), antipyretic (fever reducer) and anti-inflammatory agent and is one of the most widely used non-prescription drugs. The

More information

Hands-On Labs SM-1 Lab Manual

Hands-On Labs SM-1 Lab Manual EXPERIMENT 4: Separation of a Mixture of Solids Read the entire experiment and organize time, materials, and work space before beginning. Remember to review the safety sections and wear goggles when appropriate.

More information

EXPERIMENT 9 (Organic Chemistry II) Pahlavan - Cherif Synthesis of Aspirin - Esterification

EXPERIMENT 9 (Organic Chemistry II) Pahlavan - Cherif Synthesis of Aspirin - Esterification EXPERIMENT 9 (rganic hemistry II) Pahlavan - herif Materials Hot plate 125-mL Erlenmeyer flask Melting point capillaries Melting point apparatus Büchner funnel 400-mL beaker Stirring rod hemicals Salicylic

More information

1. Crystallization. Crystallization 1

1. Crystallization. Crystallization 1 Professor Kathleen V. Kilway and Robert levenger, Department of hemistry, University of Missouri Kansas ity, 2006 1. rystallization J.R. Mohrig, hapters 3, 14 and 15.N. Hammond, 21-28 (lab notebook and

More information

CHEMISTRY Organic Chemistry Laboratory II Spring 2016 Lab #2: Grignard Reaction: Preparation of Triphenylmethanol

CHEMISTRY Organic Chemistry Laboratory II Spring 2016 Lab #2: Grignard Reaction: Preparation of Triphenylmethanol Lab #2: Grignard Reaction: Preparation of Triphenylmethanol Purpose. In this lab you will use the Grignard Reaction, a classic reaction in organic chemistry, for the synthesis of triphenylmethanol from

More information

Lecture and Lab Skills Emphasized Synthesizing an organic substance. Understanding and applying the concept of limiting reagents.

Lecture and Lab Skills Emphasized Synthesizing an organic substance. Understanding and applying the concept of limiting reagents. E x p e r i m e n t Synthesis of Aspirin Lecture and Lab Skills Emphasized Synthesizing an organic substance. Understanding and applying the concept of limiting reagents. Determining percent yield. Learning

More information

experiment #2 - synthesis and recrystallization of dibenzalacetone

experiment #2 - synthesis and recrystallization of dibenzalacetone experiment #2 - synthesis and recrystallization of dibenzalacetone Introduction and Purpose Recrystallization is, by far, the most common way in which solid organic compounds are purified. Since experimental

More information

EXPERIMENT 2 Separation of a Mixture

EXPERIMENT 2 Separation of a Mixture EXPERIMENT 2 Separation of a Mixture INTRODUCTION The physical separation of the components of a mixture is the goal of this experiment. Each component in a mixture retains its individual physical properties.

More information

PREPARATION OF ASPIRIN AND ACETAMINOPHEN

PREPARATION OF ASPIRIN AND ACETAMINOPHEN PREPARATION OF ASPIRIN AND ACETAMINOPHEN 1996 by David A. Katz. All rights reserved. Reproduction permitted for education purposes as long as original copyright is included. OBJECT To synthesize some common

More information

ISOLATION OF CAFFEINE FROM TEA

ISOLATION OF CAFFEINE FROM TEA ISLATIN F CAFFEINE FRM TEA Introduction In this experiment, caffeine is isolated from tealeaves. The chief problem with the isolation is that caffeine does not exist alone in the tealeaves, but other natural

More information

Recrystallization II 23

Recrystallization II 23 Recrystallization II 23 Chem 355 Jasperse RECRYSTALLIZATIN-Week 2 1. Mixed Recrystallization of Acetanilide 2. Mixed Recrystallization of Dibenzylacetone 3. Recrystallization of an Unknown Background Review:

More information

experiment5 Understanding and applying the concept of limiting reagents. Learning how to perform a vacuum filtration.

experiment5 Understanding and applying the concept of limiting reagents. Learning how to perform a vacuum filtration. 81 experiment5 LECTURE AND LAB SKILLS EMPHASIZED Synthesizing an organic substance. Understanding and applying the concept of limiting reagents. Determining percent yield. Learning how to perform a vacuum

More information

Recrystallization I 15

Recrystallization I 15 Recrystallization I 15 Chem 355 Jasperse RECRYSTALLIZATIN Background: Impurities often contaminate organic compounds, whether they have been synthesized in the laboratory or isolated from natural sources.

More information

Separation by Solvent Extraction

Separation by Solvent Extraction Experiment 3 Separation by Solvent Extraction Objectives To separate a mixture consisting of a carboxylic acid and a neutral compound by using solvent extraction techniques. Introduction Frequently, organic

More information

CSUS Department of Chemistry Experiment 4 Chem.1A

CSUS Department of Chemistry Experiment 4 Chem.1A Name: Section: Experiment 4: Synthesis of Alum Pre-laboratory Assignment (Read through the experiment before starting!) 1. a) What are the strong acid and strong base used in this synthesis? b) What should

More information

CH 241 EXPERIMENT #5 WEEKS OF OCTOBER 29 AND NOVEMBER 5, 2001 CHEMICALLY ACTIVE EXTRACTION INFRARED SPECTROSCOPY

CH 241 EXPERIMENT #5 WEEKS OF OCTOBER 29 AND NOVEMBER 5, 2001 CHEMICALLY ACTIVE EXTRACTION INFRARED SPECTROSCOPY CH 241 EXPERIMENT #5 WEEKS OF OCTOBER 29 AND NOVEMBER 5, 2001 CHEMICALLY ACTIVE EXTRACTION INFRARED SPECTROSCOPY A. Background In this experiment you will use extraction and acid-base chemistry to separate

More information

Recrystallization and Melting Point Determination. W. H. Bunnelle, L. A. Meyer, R. E. Glaser (Version 3)

Recrystallization and Melting Point Determination. W. H. Bunnelle, L. A. Meyer, R. E. Glaser (Version 3) Recrystallization and Melting Point Determination W. H. Bunnelle, L. A. Meyer, R. E. Glaser (Version 3) Introduction Consider what happens when a solid material is placed in a solvent in which it has a

More information

Lab # 4: Separation of a Mixture Lab Objective Introduction

Lab # 4: Separation of a Mixture Lab Objective Introduction Name: Lab Partner(s): Date Completed: Lab # 4: Separation of a Mixture Lab Accelerated Chemistry 1 Objective You will be given a mixture containing sodium chloride (NaCl, table salt), benzoic acid (C 7

More information

Separation of Active Components from Excedrin ES

Separation of Active Components from Excedrin ES Separation of Active Components from Excedrin ES Purpose: The purpose of this lab is to isolate the active components present in Exedrin ES tablets, namely acetaminophen, aspirin, and caffeine. To accomplish

More information

2. Synthesis of Aspirin

2. Synthesis of Aspirin This is a two-part laboratory experiment. In part one, you will synthesize (make) the active ingredient in aspirin through a reaction involving a catalyst. The resulting product will then be purified through

More information

EXPERIMENT 1: MELTING POINTS

EXPERIMENT 1: MELTING POINTS EXPERIMENT 1: MELTING POINTS 1. Prepare a known sample of urea and determine its melting point. (Use a well packed capillary with ~1-2 mm of sample, with a rise in temperature of ~ 1-2 o C per min near

More information

The Synthesis of a Medicinal Agent- Aspirin. By Walter Scharf and Charles Malerich Natural Sciences/Chemistry Baruch College New York, NY 10010

The Synthesis of a Medicinal Agent- Aspirin. By Walter Scharf and Charles Malerich Natural Sciences/Chemistry Baruch College New York, NY 10010 The Synthesis of a Medicinal Agent- Aspirin By Walter Scharf and Charles Malerich Natural Sciences/Chemistry Baruch College New York, NY 10010 Introduction Salicylic-acid-containing compounds derived from

More information

Aspirin Synthesis H 3 PO 4

Aspirin Synthesis H 3 PO 4 Aspirin Synthesis Experiment 5 Aspirin is the common name for the compound acetylsalicylic acid, widely used as a fever reducer and as a pain killer. Salicylic acid, whose name comes from Salix, the willow

More information

Experiment C. Acid-Base Extraction: Benzoic Acid, 4-Nitroaniline, Naphthalene

Experiment C. Acid-Base Extraction: Benzoic Acid, 4-Nitroaniline, Naphthalene rganic hemistry I Lab HEM 2211L (Spring 2008) School of Science & Technology Georgia Gwinnett ollege Experiment. Acid-Base Extraction: Benzoic Acid, 4-Nitroaniline, Naphthalene 1. EXPERIMENTAL BJETIVES:

More information

Pure Solid Compounds: Molecules held together in rigid formations by intermolecular forces.

Pure Solid Compounds: Molecules held together in rigid formations by intermolecular forces. Recrystallization: Purification of Solid Compounds Pure Solid Compounds: Molecules held together in rigid formations by intermolecular forces. Types of Intermolecular Forces? 1. Van der Waal s forces London

More information

Experiment 2: Melting Points and the Identification of an Unknown and Cholesterol from Human Gallstones

Experiment 2: Melting Points and the Identification of an Unknown and Cholesterol from Human Gallstones 1 Experiment 2: Melting Points and the Identification of an Unknown and Cholesterol from Human Gallstones Part 1. Melting Points and the Identification of an Unknown Read pp 211-220, Chapter 14, (especially

More information

Experiment 3: Extraction: Separation of an Acidic, a Basic and a Neutral Substance

Experiment 3: Extraction: Separation of an Acidic, a Basic and a Neutral Substance 1 Experiment 3: Extraction: Separation of an Acidic, a Basic and a Neutral Substance Read pp 142-155, 161-162, Chapter 10 and pp 163-173, Chapter 11, in LTOC. View the videos: 4.2 Extraction (Macroscale);

More information

Experiment 5. Acid-Base Chemistry and Extraction

Experiment 5. Acid-Base Chemistry and Extraction Chemistry 21 Fall 2009 Experiment 5 Acid-Base Chemistry and Extraction Pre-lab preparation (1) Read the supplemental material on extraction from Fessenden, Fessenden, and Feist on the principles of Extraction.

More information

EXPERIMENT 1 ISOLATION OF CAFFEINE FROM TEA

EXPERIMENT 1 ISOLATION OF CAFFEINE FROM TEA 1-1 EXPERIMET 1 ISLATI F CAFFEIE FRM TEA In this experiment you will isolate caffeine from tea leaves and prepare the salicylate derivative. Introduction This experiment illustrates the isolation of a

More information

Preparation of Aspirin, Methyl Salicylate and Nylon

Preparation of Aspirin, Methyl Salicylate and Nylon Preparation of Aspirin, Methyl Salicylate and Nylon Experiment #6 Objective: To observe the contrasts in appearance and odor of two different esters of salicylic acid, namely aspirin and methyl salicylate.

More information

Acid/Base Extraction

Acid/Base Extraction Acid/Base Extraction Theory: Extraction is one of the most frequently used separation techniques in organic chemistry. An extraction essentially separates water-insoluble organic compounds from water-soluble

More information

Recrystallization. Good. Bad. solubility ---> Bad. temperature --->

Recrystallization. Good. Bad. solubility ---> Bad. temperature ---> Recrystallization. Recrystallization is the primary method for purifying solid organic compounds. Compounds obtained from natural sources or from reaction mixtures almost always contain impurities. The

More information

2. Add approximately 5 ml of concentrated sulfuric acid to the flask, agitate to dissolve the acetanilide and cool the mixture in an ice bath.

2. Add approximately 5 ml of concentrated sulfuric acid to the flask, agitate to dissolve the acetanilide and cool the mixture in an ice bath. CHM230 Nitration NITRATION OF ACETANILIDE TLC OF THE REACTION Introduction This exercise will follow the course of a nitration reaction using thin layer chromatography, TLC. Nitration is one of the five

More information

Experiment 2: Recrystallization & Melting Point

Experiment 2: Recrystallization & Melting Point Experiment 2: Recrystallization & Melting Point Part A: Choosing a Solvent Part B: Purification of Phenacetin Reading: Mohrig, Hammond & Schatz Ch. 15 pgs 183-197 Ch. 10 pgs 104-113 Ch. 14 pgs 174-182

More information

Experiment 7 Preparation of 1-Bromobutane

Experiment 7 Preparation of 1-Bromobutane Experiment 7 Preparation of 1-Bromobutane In this experiment you will prepare 1-bromobutane (n-butyl bromide) from n-butanol (1-butanol) using a substitution reaction under acidic conditions. This is an

More information

PREPARATION FOR CHEMISTRY LAB: A CHEMICAL SYNTHESIS

PREPARATION FOR CHEMISTRY LAB: A CHEMICAL SYNTHESIS 1 Name: Lab Instructor: PREPARATION FOR CHEMISTRY LAB: A CHEMICAL SYNTHESIS 1. Draw the structural formulas (similar to Lewis Structures, see the reaction in the introduction) for salicylic acid and acetic

More information

EXAMPLE OF LABORATORY WRITE-UP CHM 2201/2202

EXAMPLE OF LABORATORY WRITE-UP CHM 2201/2202 EXAMPLE F LABRATRY WRITE-UP CHM 2201/2202 Experiment Title: Reduction of Benzophenone Date: September 23, 2007 Name: Ima Chemist Course: 2201 Section: Lab Partner: re Ganic Statement of Purpose: To Reduce

More information

Isolation of Caffeine from Tea

Isolation of Caffeine from Tea Isolation of Caffeine from Tea Introduction A number of interesting, biologically active compounds have been isolated from plants. Isolating some of these natural products, as they are called, can require

More information

Gravimetric Analysis: Determination of % Sulfur in Fertilizer

Gravimetric Analysis: Determination of % Sulfur in Fertilizer Gravimetric Analysis: Determination % Sulfur in Fertilizer This is another "real world" sample experiment in this case we will analyze a fertilizer sample for the sulfate content and express the result

More information

Synthesis of Alum from Aluminum

Synthesis of Alum from Aluminum SYNTHESIS OF ALUM FROM ALUMINUM 53 OBJECTIVES Synthesis of Alum from Aluminum Become more familiar with single-replacement redox reactions Practice mass and volume measurement techniques Calculate the

More information

EXPERIMENT 4 QUANTITATIVE SEPARATION OF A MIXTURE OF SAND AND SALT. 1. To understand the difference between Quantitative and Qualitative.

EXPERIMENT 4 QUANTITATIVE SEPARATION OF A MIXTURE OF SAND AND SALT. 1. To understand the difference between Quantitative and Qualitative. EXPERIMENT 4 QUANTITATIVE SEPARATION OF A MIXTURE OF SAND AND SALT PURPOSE: 1. To understand the difference between Quantitative and Qualitative. 2. To determine the Quantitative composition of a mixture

More information

Alternate Methods for Recrystallization and/or Filtration. In recent years several alternative methods have been reported for the

Alternate Methods for Recrystallization and/or Filtration. In recent years several alternative methods have been reported for the 56 TECHNIQUE 5 Crystallization Alternate Methods for Recrystallization and/or Filtration In recent years several alternative methods have been reported for the recrystallization and or filtration of small

More information

EXPERIMENT 6 EXTRACTION

EXPERIMENT 6 EXTRACTION EXPERIMENT 6 EXTRACTION A. PRELAB ASSIGNMENT In your notebook, prepare a Table of Physical Constants for benzoic acid, 2-chlorobenzoic acid, salicylic acid (2-hydroxybenzoic acid), naphthalene, 1,4-dimethoxybenzene

More information

SYNTHESIS AND ANALYSIS OF A COORDINATION COMPOUND OF COPPER

SYNTHESIS AND ANALYSIS OF A COORDINATION COMPOUND OF COPPER Chemistry 111 Lab: Synthesis of a Copper Complex Page H-1 SYNTHESIS AND ANALYSIS OF A COORDINATION COMPOUND OF COPPER In this experiment you will synthesize a compound by adding NH 3 to a concentrated

More information

Preparation of Aspirin, Methyl Salicylate and Nylon

Preparation of Aspirin, Methyl Salicylate and Nylon Preparation of Aspirin, Methyl Salicylate and Nylon Experiment #5 bjective: To observe the contrasts in appearance and odor of two different esters of salicylic acid, namely aspirin and methyl salicylate.

More information

Experiment 7A The Synthesis of Artificial Hyacinth Odor (1-bromo-2-phenylethene), Part I

Experiment 7A The Synthesis of Artificial Hyacinth Odor (1-bromo-2-phenylethene), Part I Experiment 7A The Synthesis of Artificial yacinth Odor (1-bromo-2-phenylethene), Part I This two-step synthesis involves the following conversion: trans-cinnamic acid 2,3- dibromocinnamic acid 1-bromo-2-phenylethene

More information

EXPERIMENT 29 SYNTHESIS OF ASPIRIN

EXPERIMENT 29 SYNTHESIS OF ASPIRIN EXPERIMENT 29 SYNTHESIS OF ASPIRIN INTRODUCTION Aspirin is one of the most widely used medications in the world. It is employed as an analgesic (pain relief), an anti-pyretic (fever control) and an anti

More information

Secondary 3 Science (Chemistry) Chap 3: Separation Techniques Notes

Secondary 3 Science (Chemistry) Chap 3: Separation Techniques Notes Secondary 3 Science (Chemistry) Chap 3: Separation Techniques Notes Name:... Class:..... Date:........ Self-Checklist: Tick off each item after you have understood it Paper chromatography and interpreting

More information

Extraction: Separation of Acidic Substances

Extraction: Separation of Acidic Substances Extraction: Separation of Acidic Substances Chemists frequently find it necessary to separate a mixture of compounds by moving a component from one solution or mixture to another. The process most often

More information

Experiment 2 Separation of Unknown Mixture Using Acid-Base Reactions

Experiment 2 Separation of Unknown Mixture Using Acid-Base Reactions Experiment 2 Separation of Unknown Mixture Using Acid-Base eactions In this experiment you will be given an unknown mixture of three compounds, consisting of one of the two carboxylic acids, one of the

More information

Laboratory 12: Properties of Solutions

Laboratory 12: Properties of Solutions Introduction Solutions are an important class of materials we each encounter daily. This experiment will probe the physical properties of solutions. Discussion A complete discussion of solutions can be

More information

Water Lab. Objective: To distill samples of water that contains volatile and nonvolatile components.

Water Lab. Objective: To distill samples of water that contains volatile and nonvolatile components. Water Lab I. Distillation Hypothesis: Water can be purified by distillation. Objective: To distill samples of water that contains volatile and nonvolatile components. Materials and Equipment: Sodium chloride,

More information

4. Determining the Chemical Formula of an Ionic Compound

4. Determining the Chemical Formula of an Ionic Compound 4. Determining the Chemical Formula of an Ionic Compound What you will accomplish in this experiment You ve learned that compounds are a chemical combination of elements, meaning that they re created when

More information

PHYSICAL SEPARATION TECHNIQUES. Introduction

PHYSICAL SEPARATION TECHNIQUES. Introduction PHYSICAL SEPARATION TECHNIQUES Lab #2 Introduction When two or more substances, that do not react chemically, are blended together, the result is a mixture in which each component retains its individual

More information

10. Extraction: Separation of Acidic Substances

10. Extraction: Separation of Acidic Substances 10. Extraction: Separation of Acidic Substances Chemists frequently find it necessary to separate a mixture of compounds by moving or partitioning a component from one solution or mixture to another. The

More information

H 2 SO 4 heat + H 3 O +

H 2 SO 4 heat + H 3 O + Dehydration of Cyclohexanol DISCUSSION OF TE EXPERIMENT In this experiment, cyclohexanol is dehydrated by aqueous sulfuric acid to produce cyclohexene as the sole product, and carbocation rearrangement

More information

Hazards Density Melting point Salicylic acid Irritating to eyes and skin. Toxic if X

Hazards Density Melting point Salicylic acid Irritating to eyes and skin. Toxic if X Heather Graehl Title: Experiment 2: Synthesis of Aspirin Pre-lab questions: Compound Molecular weight Hazards Density Melting point Salicylic acid 138.12 Irritating to eyes and skin. Toxic if X 156-161

More information

PURIFICATION TECHNIQUES

PURIFICATION TECHNIQUES DETERMINACIÓN DE ESTRUCTURAS ORGÁNICAS (ORGANIC SPECTROSCOPY) PURIFICATION TECHNIQUES Hermenegildo García Gómez Departamento de Química Instituto de Tecnología Química Universidad Politécnica de Valencia

More information

Separation of a Mixture

Separation of a Mixture Separation of a Mixture Introduction: Mixtures are not unique to chemistry; you use and consume them on a daily basis. The beverages you drink each morning, the fuel you use in your automobile, and the

More information

Coenzyme Synthesis of Benzoin 1

Coenzyme Synthesis of Benzoin 1 Coenzyme Synthesis of Benzoin 1 Coenzyme chemistry Benzoin condensation In this experiment, a benzoin condensation of benzaldehyde will be carried out with a biological coenzyme, thiamine hydrochloride,

More information

Experiment 9 ALCOHOL DEHYDRATION (ELIMINATION) 1

Experiment 9 ALCOHOL DEHYDRATION (ELIMINATION) 1 Experiment 9 ALCOHOL DEHYDRATION (ELIMINATION) 1 There are three distinct steps in most organic preparative reactions: 1) the reaction itself, 2) isolation of the crude product, and 3) final purification.

More information

Experiment 8: Reduction of 4-t-Butylcyclohexanone with Sodium Borohydride

Experiment 8: Reduction of 4-t-Butylcyclohexanone with Sodium Borohydride Experiment 8: Reduction of 4-t-Butylcyclohexanone with Sodium Borohydride Introduction: In this experiment you will investigate the facial selectivity of the sodium borohydride reduction of 4-t-butylcyclohexanone

More information

PREPARATION FOR CHEMISTRY LAB: A CHEMICAL SYNTHESIS. 2. What is a catalyst? What is the catalyst used in this week s lab?

PREPARATION FOR CHEMISTRY LAB: A CHEMICAL SYNTHESIS. 2. What is a catalyst? What is the catalyst used in this week s lab? 1 PREPARATION FOR CHEMISTRY LAB: A CHEMICAL SYNTHESIS 1. Draw the structural formulas (similar to Lewis Structures, see the reaction in the introduction) for salicylic acid and acetic acid. 2. What is

More information

Synthesis of Para Red, part 1

Synthesis of Para Red, part 1 Synthesis of Para Red, part 1 In this lab, you prepare p-nitroaniline by the nitration of acetanilide and subsequent hydrolysis of the nitration product. You will then diazotize this compound and use the

More information

CHM220 Steam Distillation

CHM220 Steam Distillation CHM220 Steam Distillation EXTRACTION AND PURIFICATION OF NATURAL PRODUCTS FROM NUTMEG Natural products are substances that are isolated from living organisms. Parts of the plant or animal that contain

More information

Melting Point Determination Lab Melting Point Determination Lab.doc

Melting Point Determination Lab Melting Point Determination Lab.doc Melting Point Determination Lab Melting Point Determination Lab.doc Introduction: Name Date Period How Are Melting Points Used? The melting point (mp) of a pure compound is defined as that temperature

More information

Recrystallization and Melting Points. Benzoic Acid was recrystallized with a 41% recovery using 95% ethanol and water as

Recrystallization and Melting Points. Benzoic Acid was recrystallized with a 41% recovery using 95% ethanol and water as Lab #1 (Section 102) September 17, 2002 Recrystallization and Melting Points Abstract: Benzoic Acid was recrystallized with a 41% recovery using 95% ethanol and water as the mixed-solvent. Benzoic acid

More information

Laboratory 3 Mixtures and Pure Substances

Laboratory 3 Mixtures and Pure Substances Laboratory 3 Mixtures and Pure Substances Matter can be classified into two groups: mixtures and pure substances. Mixtures are the most common form of matter and consist of mixtures of pure substances.

More information

Melting Range. Melting Range 3

Melting Range. Melting Range 3 Melting Range 3 Melting Range Background Information The melting range of a pure solid organic is the temperature range at which the solid is in equilibrium with its liquid. As heat is added to a solid,

More information

Preparation of an Alum

Preparation of an Alum Preparation of an Alum Pages 75 84 Pre-lab = pages 81 to 82, all questions No lab questions, a lab report is required by the start of the next lab What is an alum? They are white crystalline double sulfates

More information

A SERIES OF CHEMICAL REACTIONS

A SERIES OF CHEMICAL REACTIONS A SERIES OF CHEMICAL REACTIONS THEORY In this experiment a massed amount of copper; metal will be made to undergo a series of chemical reaction and will finally be converted into copper metal. The changes

More information

Melting Range 1 Experiment 2

Melting Range 1 Experiment 2 Melting Range 1 Experiment 2 Background Information The melting range of a pure organic solid is the temperature range at which the solid is in equilibrium with its liquid. As heat is added to a solid,

More information

Lab 3: An ester hydrolysis and a carbon dioxide extraction

Lab 3: An ester hydrolysis and a carbon dioxide extraction Chemistry 103 bjective: Lab 3: An ester hydrolysis and a carbon dioxide extraction Introduction: In this experiment, you are going to make orange-scented soap. This requires two parts: first, the extraction

More information

Determination of a Chemical Formula

Determination of a Chemical Formula 1 Determination of a Chemical Formula Introduction Molar Ratios Elements combine in fixed ratios to form compounds. For example, consider the compound TiCl 4 (titanium chloride). Each molecule of TiCl

More information

Experiment 5 Preparation of Cyclohexene

Experiment 5 Preparation of Cyclohexene Experiment 5 Preparation of yclohexene In this experiment we will prepare cyclohexene from cyclohexanol using an acid catalyzed dehydration reaction. We will use the cyclohexanol that we purified in our

More information

Preparation & Analysis of potassium trioxalato ferrate (III) trihydrate

Preparation & Analysis of potassium trioxalato ferrate (III) trihydrate 38 Experiment #2. Preparation and Analysis of Potassium trioxalato ferrate (III) trihydrate Step One: Preparation of Ferrous Oxalate Preparation & Analysis of potassium trioxalato ferrate (III) trihydrate

More information

Experiment 15-Properties of Solutions

Experiment 15-Properties of Solutions A solution is a combination of a solvent (major component) and a solute (minor component. Solutions are heterogeneous mixtures. They may contain more than one solute. Solutes can contain solid, liquid

More information

Molar Mass by Freezing Point Depression

Molar Mass by Freezing Point Depression Experiment OBJECTIVES: Molar Mass by Freezing Point Depression In this experiment, you will determine the freezing point of cyclohexane and the freezing point of a solution containing a weighed amount

More information

FILTRATION TECHNIQUES

FILTRATION TECHNIQUES FILTRATION TECHNIQUES Filtration, the technique used to separate solids from liquids, is the act of pouring a mixture onto a membrane (filter paper) that allows the passage of liquid (the filtrate) and

More information