ORGANIC CHEMISTRY 2INDUSTRIAL APPLICATIONS

Teacher's Guide

Organic Chemistry 2: Industrial ApplicationsTeacher's Guide

This guide is designed for use with the OrganicChemistry 2 series of programs produced by TVOntario,the television service of The Ontario EducationalCommunications Authority. The series is available onvideotape to educational institutions and nonprofitorganizations. Ordering information appears on theinside back cover.

Writer: John StrattonConsultant: John EixDesigner: Janice Diner

The SeriesProducer-Director: David ChamberlainProject Officers: John Amadio, David WayWriters: James Moriarty, Cecilia KutasConsultant: John EixAnimation: Cinescan

Canadian Cataloguing in Publication DataStratton, JohnOrganic chemistry 2: industrial applications.Teacher's guide

To be used with the television program, Organicchemistry 2.Includes bibliographical references.ISBN 0-88944-130-8

1. Organic chemistry (Television program)2. Chemistry, Organic - Industrial applications -Study and teaching (Secondary) I. TVOntario. II. Title.III. Title: Oraganic chemistry two: industrialApplications. Teacher's guide.

QD251.2.5771989 547.007 C89-099617-2

Copyright 1989 by The Ontario EducationalCommunications Authority. All rights reserved.Printed in Canada. 3217/89

Cover photo: Computer animation of dioxin effects oncell nucleus. From program 6, "Life after Chemistry."

ContentsIntroduction

Program 1: Fibres

Program 2: Soaps

Program 3: Glues

Program 4: ASA

Program 5: Cosmetics

Program 6: Life after Chemistry

1

2

6

9

12

15

18

IntroductionThe six programs in this series illustrate how theproperties o£ molecules lend themselves to a widevariety of industrial applications. Because the numberof synthetic compounds being developed today issteadily increasing, the series concludes with a programdescribing the benefits and risks of these materials.

The series and guide have as their objectives:

• to explore the properties of synthetic fibres, withemphasis on the chemistry of their long-chainpolymers;• to present the functional behavior of soaps anddetergents at the molecular level, illustrating howmicelles, soluble in both oil and water, are able toremove grime;• to decribe for the viewer various properties ofconsumer glues and their unique methods of bonding:mechanical interlocking, hydrogen bonding, andpolymerization,

• to chronicle the early use of corrosive phenols as painrelievers, leading to the eventual development ofacetysalicylic acid (ASA);• to investigate the effects of cosmetics on the corneallayer of the skin by examining the eosine dyes andlakes that constitute the functional components inlipsticks; and• to chronicle the somewhat dubious history of thelong-lived pesticides, the organochlorides and DDT,focusing on the incidental production of dioxins andthe threat to all life posed by their presence in thebiosphere.

This guide provides teachers with detailed learningobjectives and descriptions for each program, andsuggests classroom activities that will enable thestudents to better understand the concepts presented inthe series.

Program 1: FibresObjectives Before Viewing

After viewing program 1 and completing this chapter,students should be able to:• Appreciate the fact that, in modern society, the

development of fibres depends on the industrialproduction of organic chemicals;

• Recognize, name, and draw the carboxyl, amino, andamide functional groups, and know their importanceas reaction sites;

• Define the following terms: monomer, polymer,hydrogen bonding, tensile strength, addition andcondensation polymerization;

• Be aware of the general properties and uses of fibressuch as cotton, rayon, nylon, and carbon-carbon fibres.

Program Description

Review the meaning of the following terms: polymer,macromolecule, monomer, carboxylic acid, amine,amide, condensation polymerisation, and covalentbond. These are terms either mentioned or shown inthis program, and a review at this time would help thestudents understand the concepts more easily whenthey watch the program.

Try to obtain samples of different types of fabrics andshow them to the students to demonstrate the variouscharacteristics of fibres:• natural fabrics: wool and silk (protein from animals);

cotton and linen (cellulose from plants)• modified natural fabrics (regenerated): viscose rayon,

acetate• synthetic fabrics: nylon, polyester, acrylic

Natural polymers have existed as long as there havebeen plants. The leaf, for example, is made of fibrescomprised of the polymer cellulose. Cellulose is amacromolecule made of roughly fourteen thousandglucose units bonded together. Each macromolecule is,in turn, twisted together with others forming the fibrewhich gives plants their characteristic strength andflexibility.

The structure of the glucose molecule is examined indetail to explain the covalent bonding that links themany molecules in the cellulose chain. This is followedby an explanation of hydrogen bonding, the processresponsible for holding the cellulose macromoleculestogether in the bundles that make up the high-strengthfibres.

The program then goes on to describe how, in the mid-nineteenth century, chemists started to experiment withthe creation of artificial fibres. The process for makingrayon is briefly outlined.

In 1939, nylon was revealed to the world. The programdescribes the long nylon molecule, and how itssegments are held together by amide functional groups.The process of extruding, twisting, and stretching thenylon to give it its strength is also shown.

The program concludes with a description of thestrongest fibres created thus far - carbon-carbon fibres.Their use in reinforcing other materials such as metalsand plastics is shown, along with an example of theiruse by the aerospace industry.

So that students can become familiar with the namesand different kinds of fibres as well as their propertiesand uses, have the students do activity 1 beforeviewing. This program stresses the organic chemistryinvolved in the formation and structure of fibres, andthe background information found in the first activitygives a general introduction to the topic.

After Viewing

Have the students do activities 2 and 3 after viewingthe program.

In activity 2, students will produce nylon, one of thepolymers discussed at length in the program. This willgive them the opportunity to handle and prepare thenecessary organic solutions and, after careful washing,to handle the product of their efforts. This experimentis also suggested in the guide for Organic Chemistry 1, inthe chapter on polyethylene (program 5); if you hadyour class perform it then, you may want to recall theexperiment and discuss its results. In any case, thisexperiment can serve as a link between the two serieson organic chemistry.

In activity 3, the students are called on to makecomparisons among various natural, modified, andsynthetic fibres. Samples of as many as possible of thefibres listed should be provided for them to examineunder microscope.

ACTIVITIES

Activity 1Types of FibresAn analysis of the following data will give a better ideaof the relationship between the properties of a fibre, itstype and its uses.

A. Study the labels on various articles of clothing:winter coats, windbreakers, slacks, skirts, sleeping bags,T shirts, sweaters, shirts, blouses, socks, etc., and fill ina table with the following headings:

Type of Article Fibre Content Properties

1. golf shirt 65% polyester, soft, comfortable35% cotton

2.

B. Make a list of the different types of fibres used in themanufacture of the articles examined above, anddescribe in which type of clothing each fibre is normallyused (e.g., in underclothing, for warm weather use, forcold weather use, for wet weather, for normal indooruse, etc.). A table similar to the following may help youkeep your data straight:

Questions1. Which fibres seem to be best suited for clothing

designed to keep the heat in?2. Which fibres seem to be best suited for clothing

designed to keep water out?'3. Which fibres seem to be best suited for clothing

designed to keep the wearer (or user) cool?4. Which fibres seem to be best suited for clothing

designed to keep the wearer comfortable when wornon a regular basis under normal conditions?

5. Which fibres seem to be best suited for clothingdesigned to keep its press (in other words, thatdoesn't need ironing)?

6. Fibres can generally be divided into three types:e natural fibres: wool and silk (protein fromanimals); cotton and linen (cellulose from plants)• modified natural (regenerated) fibres: viscoserayon, acetatea synthetic fibres: nylon, polyester, acrylic

Examine the table you prepared in part B above. Isthere any relationship between the type of fibre(natural, modified natural, or synthetic) and the type ofclothing or article normally made from that fibre?

Activity 2The Synthesis of Nylon*

A representation of the cellulose molecule in wood fibres.

When two immiscible liquids containinghexamethylenediamine and sebacoyl chloride arecarefully placed in the same container, a nylon film isproduced at the interface between the two liquids. Whenthe film is lifted from the container, it is continuallyreplaced, forming a nylon "rope" that can be woundaround a stirring rod until the reactants are used up.

Materials50 mL 0.5 mol/L hexamethylenediamine

* Adapted from Bassam Z. Shakashiri, Chemical Demonstrations: A

Handbook for Teachers of Chemistry, Madison, Wis.: The University of

Wisconsin Press, 1983. With permission.

(1,6- diaminohexane);

distilled water. Hexamethylenediamine can bedispensed by placing the reagent bottle in hot wateruntil sufficient solid has melted and can be decantedThe melting point is 39-40°C.)

plus 1.0 g NaOH in 50 mL ofsodium hydroxide, NaOH. (To prepare, dissolve 3.0 g

50 mL of 0.2 mol/L sebacoyl chloride,CICO(CH2)8COCI, in hexane.(To prepare, dissolve 1.5 mL to 2.0 mLsebacoyl chloride in 50 mL hexane.)

Gloves (plastic or rubber)250 mL beakerForceps or tongs2 stirring rodsFood-coloring dye (optional)Phenolphthalein (optional)Sodium bisulphate or sodium bicarbonate

Procedure1. Wearing gloves, put the hexamethylene-diamine

solution in a 250 mL beaker.2. Slowly pour the sebacoyl chloride solution as a

second layer on top of the hexamethylenediaminesolution, taking care to minimize agitation at theinterface. Food-coloring dyes or phenolphthalein canbe added to this solution so that the liquid interfacecan be seen better.

3. With forceps or tongs, grasp the nylon film that formsat the interface of the two solutions and pull itcarefully from the centre of the beaker.

4. Wind the nylon thread around a stirring rod a fewtimes until it is firmly attached to the rod. If youcontinue to rotate the stirring rod, the nylon rope willkeep on wrapping itself around the rod until thenylon stops forming. See figure 1.

5. Wash the nylon thoroughly with water or ethanolbefore handling.

DisposalAny remaining reactants should be mixed thoroughlyto produce nylon. The solid nylon should be washedbefore being discarded in a solid-waste container.Separate the organic waste (top layer) from the aqueouswaste (bottom layer). The organic layer should bediscarded in a solvent-waste container, and the aqueous

layer should be neutralized with either sodiumbisulphate (if basic) or sodium bicarbonate (if acidic)and flushed down the drain with water.

DiscussionThe word "nylon" is the name given to severalsynthetic polyamides. The various nylons are describedby a numbering system that indicates the number ofcarbon atoms in the monomer chains. Nylons fromdiamines and dibasic acids are designated by twonumbers, the first representing the diamine and thesecond the dibasic acid. Thus 6-10 nylon (produced inthis experiment) is formed by the reaction ofhexamethylenediamine and sebacic acid. In thisdemonstration the acid chloride, sebacoyl chloride, isused instead of sebacic acid. The equation is:

The method of reaction used in this demonstration has

O O H H O O

Ix H2N(CH2)6NH2 + x CIC(CH2)8CCI ->[- N(CH2)6N- C(CH2)8C-lx + x HCI

been termed interfacial polycondensation. This methodis used because it is a low temperature process, it israpid even at room temperature, and it does notdepend on exact stoichiometry of reactants.

Many diamines and diacids or diacid chlorides can bereacted to make other condensation products that aredescribed by the generic name nylon. One such productis an important commercial polyamide, nylon 6-6,which can be prepared by substituting adipoyl chloride(C6 diacid) for sebacoyl chloride in the proceduredescribed here. The equation is:

Figure 1.

Activity 3The Stretch and Strength ofDifferent FibresThe following activity involves the analysis of theresults obtained when threads of different fibres weretested for their stretch and strength. In each case, thethreads chosen were 100% of the indicated material,were of the same initial "rest" length, and all were two-ply. The following table shows the comparative resultsthat were obtained:

Discussion1. Draw a bar graph to illustrate the stretchability of the

fibre types listed in the above table.2. Examine your sketches of the fibres you observed.

What do you notice about the strands of the fibresthat are the most stretchable?

3. Draw a bar graph to illustrate the strength of the fibretypes listed in the above table.

4. Examine your sketches o£ the fibres you observed.What do you notice about the strands of the fibresthat are the strongest?

5. Examine the two bar graphs. When the stretchabilityof a fibre is compared with its strength, what patternbecomes apparent?

ReferencesBrady, J. E. and J.R. Holum. Fundamentals of Chemistry, 3rd Ed.Toronto: John Wiley and Sons, 1988.

Fritz, Anne. The Fibre o f Clothing. London: Oxford UniversityPress, 1980.

Garforth, F and J. Harding. Clothing Unit: Chemistry ResourceMaterials from the University of York. Provided by the ProgramDepartment, Scarborough Board of Education, 1985.

Pearson, John "Creasing in Fabrics," Chem 13 News (Number148), Waterloo, Ont.: University of Waterloo, March 1984.

MaterialsMicroscopeMicroscope slide1 pair of tweezersFibre samples. Some examples are

• natural: wool and silk (protein fromanimals); cotton and linen(cellulose from plants)

• modified natural (regenerated):viscose rayon, acetate

• synthetic: nylon, polyester, acrylic

Ridley, A. and D. Williams. Simple Experiments in TextileScience. London: Heinemann Educational Books, 1974.

Roberts, J. D. and M.C. Caserio. Basic Principles o f OrganicChemistry. New York: W.A. Benjamin Inc., 1965.

Procedure1. Using the tweezers, tease apart a few threads from

one of the fibre samples. Examine the threads underthe microscope, and sketch several strands; show inparticular how the strands twist or bend.

2. Repeat step 1 for each of the other strands.

Fibre Comparative Stretch(linen =1 unit)

Comparative Strength(linen =1 unit)

wool 3.80 0.30acrylic 3.55 0.44acetate 2.85 0.26nylon 2.70 0.94polyester 2.00 0.85rayon 1.65 0.36silk 1.40 0.69cotton 1.25 0.61linen 1.00 1.00

Program 2: SoapsObjectives

After viewing program 2 and completing this chapter,students should be able to:• Appreciate the fact that, in modern society, the

production of soaps and detergents depends on thedevelopment of organic chemicals;

• Recognize and draw a fat molecule, a soap molecule,and a detergent molecule;

• Define the following terms: polar molecule, nonpolarmolecule, fat, oil, soap, micelle, water hardness,chelating agent, detergent, primary alkyl sulphates;

• Be aware of the general polar and nonpolar propertiesof soap and detergent molecules, in particular, theirability to mix with water, fat, and oil molecules;

• Describe the reaction involving the formation of soapfrom a fat or fatty acid and a base;

• Describe the reaction involving the formation of adetergent from an alcohol, sulphuric acid, and a base;

• Be aware of the ingredients of a bottle of shampoo.

Program Description

This program introduces the idea that, although waterhas always been used to help people get clean, it is nota good cleansing agent in its own right. Viewers arethen shown how water is a polar substance withhydrogen bonding between its molecules. "Dirty"clothes, on the other hand, quite often contain fattysubstances released by the body, these substances arenonpolar in nature. Water and fat molecules will notmix because they have no ability to attract each other.

The program then goes on to show the stucture oftypical nonpolar fat and oil molecules and explainshow, if these molecules were altered by placing an ioniccharge on one end, they would be able to mix withwater molecules.

Steps in the manufacture of soap are shown from thereaction of a base (NaOH) with the fat molecule to theresulting sodium salt of a fatty acid. This final sodiumsalt of the fatty acid is the soap molecule with both anionic end and a nonpolar end. The ionic end of thismolecule will dissolve in water, and the nonpolar endwill dissolve in oil or fat.

Soap molecules are shown forming spheres calledmicelles that surround an oil glob by associating withthe nonpolar end of the soap molecule. The micellesmix with water and suspend the oil glob when the ionicend of the soap molecules interact with the polar watermolecules. The oil glob can then be washed away andrinsed down the drain.

If the water is hard, the sides of the wash tub have to becleaned when the soap molecules interact with the hardwater ions to form an insoluble salt. The use ofexpensive chelating agents is shown as one way toovercome this problem.

As another approach to the problem of hard water,chemists developed soap-like substances calleddetergents. These are molecules with 10 to 18 carbonatoms on the nonpolar chain, and sulphate ions in placeof the carboxylate ion on the soap molecule.

The program concludes with a description of howdetergents are used in shampoos, along with a list oftypical shampoo ingredients.

Before Viewing

Review with your students the dissolving process,paying particular attention to the rule "like dissolveslike." Make sure, too, that your students are familiarwith the meaning of polar and nonpolar molecules, asthese are referred to frequently during the program.

After Viewing

All three activities should be done after viewing theprogram. The first activity has the students preparesoap, the second demonstrates the effect of hard wateron soap, and the third shows how to prepare adetergent. The program discusses all three of thesetopics, and the activities will serve both as review andreinforcement.

Soap molecules, surrounding an oil glob, are suspended in water.

ACTIVITIES

Activity 1Making Soap

Activity 2Using Soap in Hard Water

Fats and oils are the glycerol esters of fatty acids. Theonly real difference between them is that fats areusually considered solids whereas oils are liquids. Inindustry, tallow (fat from cattle) and coconut oil are themost common substances used to produce soap. As theprogram shows, when sodium hydroxide is added tothe fat and oil reactants, both soap and glycerol areproduced; the glycerol byproduct is saved and used forother purposes. In this activity, however, a fatty acidalone will be used to produce soap, and a glycerolbyproduct will not be formed; this process would betoo expensive for industry.

Procedure

2. Slowly add the 16 mL 1.0 mol/L NaOH(aq) to thecontents of the large test tube, and stir with thestirring rod.

3. Put some water (approximately 50 mL) into the"dirty" beaker. Dip the test tube brush into theproduct formed in the large test tube, and then foait up in the water in the beaker. Rinse the beaker a]scrubbing it for 30 s and compare it to the way itlooked before the wash. CAUTION: Do not use thisoap on your hands: it may be acidic or basic.

3. Give two reasons to explain why the traditionalmethod of soap production (using tallow andcoconut oil) is more economical than the methodused in this experiment.

In this activity, you will add soap solution to distilledand tap (hard) water to observe how calcium andmagnesium ions affect soap.

5 mL 0.50 mol/L NaCl (aq) prepared withdistilled water

Distilled waterTap waterStandard soap solutionEye dropper10 mL graduated cylinder

Procedure1. To one of the test tubes, add 15 mL of distilled water.

Label the tube #1.2. To three of the test tubes, add 10 mL of distilled water

and label them #2, #3, and #4.3. To the fifth test tube, add 15 mL of tap water.4. Using the dropper, add standard soap solution drop-

by-drop to each test tube in turn until a permanentlather forms. The lather should last about 15 s.Record your data in the form of a table. Describe theresulting mixture after the bubbles have had a chanceto break.

Discussion1. Distilled water contains only water molecules, with

all other impurities removed. Compare the number ofdrops required to reach a permanent lather in tubes#2, #3, and #4 with the number of drops used in #1.

2. Which ions appear to cause hardness in water?3. Based on your data and visual observations, explain

the problem of using soap in hard water.4. By comparing the number of drops required to reach

a permanent lather in tube #5 with the number ofdrops used in #1, what can you conclude about thetap water that you used?

16 mL 1.0 mol/L NaOH(aq)Test tube brushLarge test tube"Dirty" beakerStirring rodSafetv goggles

Materials5 mL oleic acid, ci:s.

responsible for hardness in tap water, write thebalanced equation for the reaction between theCat+ (aq) ion and the soap. Use the formula for thesoap that you made in activity 1.

i ion is one of the ions5. Assuming that the I

1. Put the 5 ml, oleic acid,into the

large test tube,

prepared withdistilled water

prepared withdistilled water

Materials5 test tubes of equal size

Discussion1. Write the balanced equation for the reaction that

takes place in this activity. This is a neutralizationreaction.

2. If tallow had been used, one of the fats it contains is. Write theglycerol palmitin,

balanced equation for this reaction.

Activity 3Making DetergentThe problems associated with the use of soap in hardwater can be overcome by using detergents. Thefollowing activity asks you to prepare a detergent anduse it to clean oil from a container.

5 mL olive oilElectric hot plateDistilled waterGraduated cylinderGoggles

Procedure1. Wearing goggles, put the 1-hexadecanol (cetyl

alcohol), C16H330H, into the 250 mL beaker andwarm slowly on the hot plate. Using the eye dropper,add the concentrated H2S04 drop-by-drop until the1-hexadecanol completely dissolves. Remove fromthe heat.Cool the mixture and then slowly pour it into 50 mLof distilled water, stirring as you pour.Add the 2.5 mol/L NaOH solution until the solutionjust becomes basic. This can best be done by adding2 or 3 mL of the base, stirring, and then placing theend of the red litmus paper in the solution to see if itturns blue. If not, add 2 more mL of NaOH and testthe solution again; repeat until the litmus paperturns blue.To test for the presence of the detergent, add onedrop of olive oil to 5 ml, of water in the test tube, andthen pour in about 5 mL of the detergent solutionprepared in step 3 above. Place a rubber stopper onthe tube and shake. Describe the appearance of themixture in the tube before and after adding thedetergent.

2.

3.

4.

5. Into the second test tube, pour 5 ml of the detergentsolution prepared in step 3 above. Add 5 mL of the0.50 mol/L Ca(OH)2 solution to this tube, cover witha stopper, and shake. Describe the appearance of themixture in the test tube.

Discussion1. When the sulphuric acid is added to the

ReferencesCapindale, J. B.,"Analysis of Lipids," Chem 13 News ( Number158), Waterloo, Ont.: University of Waterloo, April 1985.

Cherkas, Andy, "Demistry," Chem 13 News ( Number 144),Waterloo, Ont.: University of Waterloo, November 1983.

Messer, M.B. at al. Introductory Experimental Chemistry.Toronto: Prentice-Hall, 1977.

Morrison, R. T. and R.N. Boyd. Organic Chemistry, 3rd ed.Boston: Allyn and Bacon, 1974.

Nimmo, W. S. The World of Carbon. Toronto: Wiley, 1977.

Shapiro, Brenda B. Consumer Appplications in Chemistry.Scarborough: Scarborough Board of Education, 1984,

1-hexadecanol (cetyl alcohol), in step 1 ofthe procedure. a sutnhonation reaction occurs andthe OH of themolecule with one of the H atoms of the sulphuricacid. If the 1-hexadecanol and the sulphuric acidmolecules bond together, the remaining portionsform what is known as a sulphonated alkylate. Showthe balanced equation for this reaction.

2. After the reaction in question 1 above, the acidicproduct is neutralized with NaOH (step 3 of theprocedure). Write the balanced equation for thisreaction.

3. Describe the effect of the detergent on the olive oilmixture.

molecule forms a water

combined with the detergent in step 5of the procedure is one of the ions responsible forhard water. What effect did it have on the latheringproperties of the detergent?

5. In what ways are detergents like soaps?6. In what ways do detergents differ from soaps?

4. The

25 mL of 0.50 mol/L Ca(OH)2

Small bottle of concentratedEye dropperRed litmus paperStirring rod50 rnL of 2.5 mol/L NaOH

Materials2 test tubes2 rubber stoppers to fit the test tubes.75f1 mT. hpakpr2.0 g 1-hexadecanol (cetyl alcohol),

Program 3: GluesObjectives

After viewing program 3 and completing this chapter,students should be able to:• Appreciate the fact that, in modern society, the

production of glues with a variety of differentproperties depends on the development of organicchemicals;

• Define the following: adherend, tensile strength,shear strength, cleavage, peel, cure, and glasstransition temperature;

• Recognize the characteristics of a glue that give itphysical strength, resistance to chemicals, and theability to withstand thermal stress;

• Describe the reaction involving the formation of crazyglue when cyanoacrylate polymerizes in the presenceof water;

• Recognize the importance of glues with a high glasstransition temperature and of glues with a low glasstransition temperature.

according to how the glue will be used. We are shownhow, in order to increase the glue's bonding strength,the chemical inertness of the glue suffers, and viceversa. This is some indication of the compromises thathave to be made in order to come up with a glue that issatisfactory for particular uses.

The glass transition temperature is the highesttemperature at which the glue can begin to solidify.This property can be altered by varying the number ofelectronegative atoms in the polymer. This importantproperty has led to the development of hot-meltadhesives based on ethylene vinyl acetate. Numerousindustrial applications exist for this type of glue which,under heat, turns from solid to liquid, and then turnsquickly back to solid after application. The programends by pointing out the usefulness of pressure-sensitive glues with a low glass transition temperature,especially when you want something like a bandage topeel off easily without removing one of the adherends- your skin.

Program Description Before Viewing

Program 3 begins by examining the concept ofstickiness, and goes on to categorize glues. Water isused as an example of a substance that makes a papercoaster stick to a wet glass when hydrogen bonds formbetween the water molecules and the oxygen atoms inthe glass and paper. When we see the very differenttensile and shear strengths of this "glue" at roomtemperature and below the freezing point, it is obviousthat a good glue should be liquid when it is applied butshould become solid very quickly at room temperature.Since most adherends have imperfections in theirsurfaces, the glue is able to penetrate while it is in theliquid state.

One group of organic substances that can be changedfairly quickly from liquid to solid with the aid ofcatalysts, air, or light, is the polymer group. "CrazyGlue" is used as an example of a liquid thatpolymerizes on contact with a weak alkaline solution orwater moisture. Details are shown of the reactionbetween the thin layer of cyanoacrylate molecules andwater molecules producing a quickly solidifiedpolymer.

Review the concepts of electronegativity and hydrogenbonding, as well as material on polymers. You might wantto view again, or go over the material presented in theprograms "Polyethylene" (Organic Chemistry 1, program 5),and "Fibres" (Organic Chemistry 2, program 1).

After Viewing

This very long activity should be done after viewing theprogram. Much of what is contained in the discussionsection has been covered in the program itself.

You may decide to use this activity as a demonstrationand do it yourself in front of the class. Remember,though, that you will have more consistent results ifyou can use group or class averages.

If you have all the students do the experiment, youmight prefer to have them perform the tests in groups:one quarter of the class could do one of the tests withall their blocks, while another quarter of the class doesanother test, and so on.

The program discusses three good characteristics of acured glue: resistance to chemical attack provided byhydrocarbon chains; structural integrity giving stiffnessand strength -- provided by hydrogen bonding betweenthe electronegative atoms of the hydrocarbon chains;resistance to thermal stress - provided by theappropriate glass transition temperature that varies

ACTIVITIES

Activity 1Preparation and Testing of SomeSimple Glues

This activity shows how to make a variety of glues, andsuggests some simple ways of testing them for strength.

Materials40 g skim milk powder3 g lime (or calcium oxide), CaO40 g all-purpose flour80 g corn starchDistilled water as needed4 250 mL beakersStirring rod10 blocks of wood, their surfaces as flatand smooth as possible. (Although thedimensions are optional, blocks of3 cm x 3cm x 2 cm are recommended.)

10 threaded eyes (to be screwed into thecentre of each of the blocks of wood)

20 elastic bands (to hold the woodenblocks together while the glue sets)

Refrigerator with a freezerSlotted screw driverHammer1000 mL beaker

constantly until the mixture forms a smooth paste. Becareful not to add too much water.

Use the stirring rod to spread this paste on the gluingsurfaces of another pair of blocks, and hold themtogether with two elastics, as above. Use only enoughof the mixture to coat the surface thinly (the excesswill be squeezed out when the elastics are put on).Put this aside to dry until the next day or longer ifnecessary. Make sure to write on the blocks which"glue" has been used.

3. In another 250 mL beaker, use flour in place of skimmilk to make another glue. Apply this paste toanother pair of blocks just as you did before. Writethe name of your "glue" on the blocks.

4. Put 40 g of cornstarch into a 250 mL beaker. Adddistilled water at room temperature and stirconstantly until the mixture is like a smooth cream.Be careful not to add too much water. Slowly addboiling water, stirring constantly until the mixturesuddenly thickens. Then stop adding water butcontinue stirring until the mixture becomes smooth.

Apply this paste to another pair of blocks exactly asyou did above. Be sure to write the name of the"glue" that you used.

ProcedureBefore beginning, screw the eye hooks into the centre ofeach of the wooden blocks.1. Take one pair of wooden blocks and wet the two

gluing surfaces with distilled water as shown infigure 2. Place two elastics around the two blocks tohold them tightly together, and put them into thefreezer until the next day. Write on your blockswhich "glue" has been used.

2. Put the 40 g of skim milk into a 250 mL beaker. Addwarm (about 40°C) distilled water, stirring

Figure 2.

5. Repeat the above step, but combine the 3 g of CaOwith another 40 g of cornstarch before starting to addthe water. Apply the paste to another pair of blocksexactly as you did before, and write on the blocks thename of the "glue" that has been used.

Testing the GluesThe following tests are qualitative in nature and areintended as a means of comparing the glues with oneanother. You will have to decide which glue is "best,"

The polymerization reaction that solidifies "Crazy Glue."

"second best," etc. This might be done more easily ifyou assign a value of 5 for the strongest glue, 4 for thesecond strongest, and so on down to 1 for the weakest.

Set up a table similar to the following on which torecord your data. Once the table is completed, you cantotal the values to determine the overall ratings for eachglue; the glues can also be compared side by side forspecific properties. If you get together with yourclassmates to collect all your results, averages can beworked out to give you a better idea of how the gluescompare with one another.

Tensile strength+

Figure 3.

Test for Tensile StrengthTake each of the glued block assemblies, one at a time,and pull on the screw eyes in the direction indicated infigure 3. Rate each glue as indica ted above. Record yourdata.

Test for Shear StrengthTake each of the glued block assemblies one at a time,and push on the sides in the direction indicated infigure 3. Hold the blocks in the palms of your hands andtry to slide them sideways. Rate each glue as indicatedabove and record your data.

Test for Cleavage StrengthTake each of the glued block assemblies one at a timeand put it on its side. Put the slotted screwdriverbetween the two blocks and give it a tap with a hammeror similar object. If you are able to insert the screwdriver

but the blocks remain stuck together, try to pry themapart by carefully applying force in the directionindicated in figure 3. Rate each glue and record yourdata.

Test for Water ResistancePlace all the glued block assemblies in a 1000 mL beaker ofcool water. Every minute, apply a shear type of force asshown in figure 3. Rate each glue and record your data.

Discussion1. From information provided in the program, explain

how the water was able to act as a glue.Wood is made of cellulose and contains a highproportion of oxygen atoms. Draw and label a simplediagram showing the arrangement of watermolecules between the two surfaces that help explainits bonding properties.What is one obvious drawback of using water as aglue?

2. The composition of flour depends on the type ofwheat and the milling process. However, the mainingredients of flour are proteins and starch, with asmall amount of sugar. Research the structure oftypical proteins and starch. By considering the type ofatoms, the structure of the molecules, and wood withits high proportion of oxygen atoms, would youexpect flour to be an effective glue? Explain.

3. Milk is partly composed of a phosphorus-containingprotein known as casein. Comment on the adhesiveproperties of milk as shown by this experiment, andexplain whether you would expect milk to make agood glue.

4. As mentioned in question 2 above, flour containsboth protein and starch. After the various tests havebeen completed, compare the glue made from flourwith the glue made only from starch.In what way do you think the presence of proteins

and sugars in the flour affected the characteristics ofthe glue?

5. Use the results of the tests to compare the starch-onlyglue with the starch+CaO glue. In what way did theCaO influence the properties of the glue? Explain whyyou think the CaO had this effect.

6. According to the results of the tests, which is the bestglue? Explain your choice.

ReferencesHoadley, R. B., "Glues and Gluing," Fine WoodworkingTechniques. Newtown, Conn.: The Taunton Press, 1978.

Mustoe, G., "Which Glue Do You Use?," Fine WoodworkingMagazine, Nov.-Dec. 1983, Number 43, Newtown, Conn.: TheTaunton Press.

Shapiro, Brenda B. Consumer Appplications in Chemistry.Scarborough: Scarborough Board of Education, 1984.

Type of Glue

Test Water Flour Cornstarch Starch+CaO

Tensile Strength

Shear StrengthCleavage StrengthWater Resistance

Total

Progra: ASA

ObjectivesAfter viewing program 4 and completing this chapter,students should be able to:• Appreciate the fact that, in modern society, the

production and modification of pharmaceuticals suchas pain killers depend on the development of organicchemicals;

• Recognize and draw a molecule of acetylsalicylic acid,salicylic acid, and acetaminophen;

• Define the following: salicylates and prostoglandins;• Be aware of the positive and negative effects of ASA;• Describe the reaction involving the formation of

sodium salicylate from salicylic acid and sodiumhydroxide;

• Describe the reaction involving the formation ofacetylsalicylic acid from salicylic acid and aceticanhydride;

• Be aware of the way in which ASA operates as a painkiller, fever reducer, and anti-inflammatory agent;

• Be aware of alternative nonnarcotic pain killers likeacetaminophen;

• Be aware of the differences among different brands ofASA;

• Be able to describe a method to test aspirin for purity.

A discussion is introduced regarding the possible abuseof ASA, with the one hundred thousand tonnes ofaspirin consumed yearly given as an example. Thedangers of abuse are evident: because pain is the body'ssignal that something is wrong, using aspirin to blockthe pain could mean ignoring a potentially seriousinjury or disease. And chronic use can lead to pepticulcers, caused when the mucous layer of the stomach isreduced by ASA.

The program concludes with information regarding thedifferences among various brands of ASA. As well,other phenol-based analgesics such as acetaminophenare mentioned, and the properties of this latter pain-reliever are briefly compared to those of aspirin.

Before Viewing

Have the students do activity 1 before viewing theprogram. This activity calls for them to prepare ASA.Since the reaction is shown as part of the program, thestudents will better understand the explanation of thereaction if they have used the reactants themselves andcollected the product.

Program Description After ViewingThis program begins by introducing salicylic acid, asubstance originally obtained as an extract from thebark of the willow tree. When it was first given topatients, it failed to cure them; however, it did relievethe pain, fever, and swelling associated with theirillnesses.

Next are shown two attempts made to reduce thecorrosive nature of the salicylic acid. In the first, thereaction of the salicylic acid with sodium hydroxideproduces the too-sweet sodium salt, sodium salicylate.In the second method, the reaction of salicylic acid withacetic anhydride produces acetylsalicylic acid, morecommonly known as aspirin or ASA.

As the program explains, this nonnarcotic drug (ASA)rapidly became the most effective and least harmfulpain reliever known, one that could also reduce feverand swelling. For many years, though, nothing wasknown about how or why ASA worked so well.

The program goes on to outline the manner in whichASA is now believed to work by interrupting theproduction of the different types of chemicalmessengers (prostoglandins) that travel from theinjured or diseased part of the body to the brain.

Activities 2 and 3 are best kept until after the program.They involve either the detection of impurities inaspirin, or a discussion of its possible harmful sideeffects. Because the first part of the program touches onthese topics, the students will be better prepared tounderstand the intent of these activities after they haveviewed the program.

Activity 3 works well as a debate. Divide the class intotwo groups and have one group research the advan-tages of aspirin and its use, while the other groupresearches its disadvantages.

The structural formula o f acetylsaliclic acid (ASA)-common asprin.

ACTIVITIES

Activity 1The Preparation of Aspirin

The following activity shows you how to prepare ASAfrom salicylic acid and acetic anhydride with asulphuric acid catalyst.

Materials5.0 g salicylic acid, HOC6H4000H7.0 mL acetic anhydride, (CHSCO)20Concentrated sulphuric acid (a few drops)2 - 600 ml, beakers250 mL Erlenmeyer flaskFunnelFilter paperCrushed iceSafety gogglesDisposable glovesStirring rod

3. Carefully add 3 drops of concentrated sulphuric acicand gently swirl the contents of the flask for 2minutes.

4. Place the Erlenmeyer flask in a water bath heated to9000, and continue heating for 10 minutes.

5. Remove the reaction mixture from the water bathand, while it is still hot, add 5 mL of water todecompose the excess acetic anhydride.

6. When this reaction stops, add 40 mL of water and lethe flask stand while crystallization starts.

7. To the other 600 mL beaker add water and crushedice until it is approximately two thirds full. Addanother 25 mL of cold water to the Erlenmeyer flaskand stand the flask in the ice bath. Allow it to chillthoroughly.

8. Filter the crystals from the Erlenmeyer flask, washthem with 10 mL of ice water, and allow them to dryovernight (or until the next class). Describe the ASAcrystals. Save them for activity 2.

H2SO4

Discussion1. Draw the structural formula of salicylic acid and

acetic anhydride.2. When the salicylic acid and acetic anhydride

combine, the H atom of the hydroxyl group on thesalicylic acid molecule is replaced with an acetylgroup (-C-CH3)

I IO

from the acetic anhydride molecule to formacetylsalicylic acid.The remaining portion of the acetic anhydridemolecule and the H atom released from the salicylicacid molecule combine to form an acetic acidmolecule.Show the structural formulas of the two products inthis reaction.Write the balanced chemical equation for the reactionthat has taken place.

3. The sulphuric acid used in this activity is a catalyst.What is the role of a catalyst?

4. Considering the way in which the crystals are formedin this activity, comment on the solubility of ASA incold water.

Activity 2Testing AspirinSalicylates in concentrated solution can destroy mucoustissue and cause gastric upset and bleeding. Onceingested, aspirin is hydrolyzed to salicylic acid andacetic acid. It will also slowly hydrolyze in its storagebottle and produce the same products.

This activity gives a qualitative test for salicylic acid.First, salicylic acid is used to confirm that a colorchange does occur when the test reagent is added, andthen the test is carried out for the salicylate ion in theaspirin prepared in activity 1 and in aspirin tabletspurchased commercially.

1. Put 5.0 g of salicylic acid,250 mL Erlenmeyer flask.

in a

2. Wearing the disposable gloves. slowly add theacetic anhydride,the salicylic acid.

to the flask containing

Materials0.324 g aspirin (acetylsalicylic acid crystals) collected in

activity 1Aspirin tablet containing 0.324 g aspirin (purchased

commercially)10.0 g salicylic acid added to enough 2:1 water:ethanol

solution to make 1.0 L of solution

Procedure1. Put approximately 1 mL of the salicylic acid solution

in one of the test tubes. Add about 5 ml, of FeC1 3 testsolution. Record your observations and leave the tubestanding in the rack for comparison with the othertubes after steps 2 and 3.

2. Put 0.324 g aspirin (acetylsalicylic acid crystals)collected in activity 1 in a second test tube. Add 3 or 4drops of the FeC13 test solution to these crystals.Record your observations and leave the tube standingin the rack for comparison with the other tubes.

3. Put one of the commercially prepared aspirin tabletsin the third test tube. Add 3 or 4 drops of the FeC13test solution to the tablet. Record your observationsand leave the tube standing in the rack forcomparison with the other tubes.

4. Compare the effect of the FeC13 test solution on thecontents of the three tubes.

Discussion1. Describe the observations expected when a FeC13 test

solution is added to a substance known to contain thesalicylate ion.

2. Comment on the purity of the aspirin prepared inactivity 1.

3. Suggest reasons for expecting the aspirin collected inactivity 1 to contain impurities.

4. Comment on the purity of the commercially preparedaspirin tablet.

5. Why do you think the commercially prepared aspirintablet might test positive for the salicylate ion eventhough it was prepared under very carefulconditions?

6. Symptoms of mild aspirin poisoning include aburning pain in the mouth, throat, and abdomen. Dothe results of this activity suggest a possible cause forthese symptoms?

7. Aspirin is frequently used by arthritis sufferers, whomay take 12 or more tablets daily and, as a result,may suffer from gastric upset. To counter theseunwanted side effects, people with arthritis may beadvised to take buffered or coated aspirin.

Find out what buffered aspirins contain in addition towhat is found in regular aspirin.Find out how coated aspirins differ in the way theywork once they enter the stomach. If possible, findout what the coating consists of.

Activity 3The Advantages andDisadvantages of Aspirin

With a group of your classmates, research either theadvantages or the disadvantages of aspirin and its use.From your findings, prepare notes that you can use in adebate of the question Aspirin is a helpful drug.

DiscussionThere are many reasons why aspirin is such a populardrug. It is used to relieve pain, to lower bodytemperature, and to reduce inflammation. Because itslows the rate of blood clotting, it may be also useful forpatients subject to heart attacks and strokes.

However, there are several problems associated withthe use of aspirin, including coagulation problems insome people, allergic reactions, stomach irritation,accidental poisoning, and a possible link to Reye'ssyndrome.

In the bibliography below, the works by Linus Pauling,Joe Graedon, and Jo Currie contain references to aspirinas both a wonder drug and a substance that is more of aproblem than a help. There are many other sources ofinformation: these are just a beginning.

References

"Aspirin: History," Scientific American, November 1963.

Canadian Pharmaceutical Association. Compendium ofPharmaceuticals and Specialties, 1986. Toronto: SouthamMurray, 1986.

Currie, Jo, "Heart Attack!", Canadian Living Magazine,September 3,1988.

Graedon, Joe. The People's Pharmacy 2. New York: Avon Books,

1980.

Korolkovas, A. and J. H. Burkhalter. Essentials of MedicinalChemistry. NewYork: John Wiley and Sons, 1976.

Pauling, Linus. How to Live Longer and Feel Better. New York:Avon Books, 1986.

0.10 mol/L iron (III) chloride ) prepared bydissolving 19.9 g ofwater to make one litre of solution.

3 test tubesTest tube rack

in enough distilled

Program 5: CosmeticsObjectives

Program Description

Program 5 is about our skin and some of the cosmeticsthat we use on it every day. Cosmetics include soaps,cleansers, shampoos, toothpaste, lipstick, and manyother products that beautify and cleanse.

The manner in which soaps and detergents remove oilis reviewed from program 2 on soaps. In addition, weare shown why lanolin has to be added to soapsintended for use on the skin.

The program then discusses lipstick as an example ofone substance that is intended to beautify rather thancleanse the skin. Because the skin on the lips differsfrom skin elsewhere on the body, it chaps more readilyand may become infected. These characteristics lead toa discussion of the health hazards associated with usinglipstick that others have used.

Lipstick prevents chapping; the real reason for using it,though, is that it adds color to the lips. A discussion ofthe two types of lipstick dyes is presented, and theadvantages and disadvantages of each are shown.

Consumer demand for lipstick is created throughadvertising; to satisfy this demand, a lipstick is madethat will remain solid until it is applied but becomesliquid once it is on the lips. The final product containsdyes, carnauba wax, beeswax, an antioxidant, andperfume.

Before Viewing

In this program, the manner in which soaps anddetergents remove oil is reviewed from program 2,"Soaps." However, in case this review in the programis too brief, it would be a good idea to go over thismaterial with the students before showing them theprogram on cosmetics.

Since we apply virtually all of these substances to ourskin, the program starts with a detailed study of thisimportant organ, taking us from the cells on the surfaceto the epidermis and the larger dermis below, in whichthe sweat glands, capillaries, and hair follicles arefound. The way in which the keratin, sweat glands, andsebaceous glands all work together to keep the skin softis explained.

The skin is an organ that can renew and cleanse itself.Scrubbing away the oily layer can help remove the dirtand bacteria that collect in it. We are shown how bothalcohol and cleansing creams can accomplish thiscleanup, but we also see why both are not equally goodfor the skin.

After Viewing

All the activities are designed to be completed after thestudents have viewed the program, at which time mostof the materials used will be more familiar.

Because the product of each activity is more appro-priate to one or the other sex, you might want to havethe girls in your class do activity 1, while the boys doactivity 2 (or half of them do 2A, while the other half do2B).

After viewing program 5 and completing this chapter,students should be able to:• Appreciate the fact that, in modern society, the

production of cosmetics used to cleanse and beautifyour bodies depends on organic chemicals;

• Be aware of the positive effects on the skin of sometypes of cleansers and beauty products;

• Label a diagram of the skin, showing the location ofthe epidermis, dermis, stratum corneum, stratumgerminativum, sweat glands, sebaceous glands, andhair follicles;

• Describe how skin naturally remains soft, andindicate why lanolin and oil-soluble substances mustbe added to soaps and other cleansers;

• Be aware of the problems that can arise from usingcosmetics like lipstick that others have used;

• Describe the advantages and disadvantages of thetwo types of dyes (eosines and lakes) used in lipstick;

• Describe the importance of carnauba wax, beeswax,antioxidants, and perfume in the production oflipstick;

• Prepare a liquefying cleansing cream;• Prepare a preshave and an aftershave lotion.

ACTIVITIES

Activity 1Preparation of a LiquefyingCleansing CreamThere are several properties that are expected of a goodcleansing cream. For example, it should be stable, lookattractive, spread easily when applied to the skin, andleave a light emollient film on the skin to preventdrying. Finally, it should clean the skin and poreopenings, and not be absorbed. The following type ofcream is used by people with dry skin.

Materials (to prepare 100 g of cream)62.5 g mineral oil 65/75 cPoise (light-medium

viscosity). This is the solvent for the oils and greasesthat are to be removed from the skin.

18.5 g petrolatum (petroleum jelly). This is an emollientthat stays on the skin to keep it from drying out. Italso adds to the body and stability of the cream.

12.5 g paraffin 125/127 (wax or heavy mineral oil).Another emollient, this keeps the skin from dryingand also keeps the cream slightly thick until it meltswhen rubbed on the skin.

6.25 g beeswax (bleached white, mp = 62-65 OC,acid #17-24). This is another emollient that stays onthe skin to keep it from drying.

0.25 ml, perfume. This is optional: its purpose is makethe product attractive.

Thermostatically controlled hot plateStirrer (overhead or magnetic)2 250 ml, glass beakers (if using an overhead stirrer, one

of the beakers must be metal or plastic)50-100 mL beakerDisposable weighing pan or watch glassBalanceSample bottle in which the product can be kept

8. Turn off the heat and, continuing to stir, allow themixture to cool to 50°C. If perfume is going to beadded, mix it in at this point.

9. Pour the cream into a sample bottle and label it.

Discussion (and testing the product)1. Describe the product after it has come to room

temperature.2. Put some of the cream on your skin and wash it off

with water. Note the results and state what type ofproduct you have made: it will be polar if water willwash it off, and nonpolar if not.

3. Rub some eye makeup or lipstick on your hand.Work some of your cream over it, and wipe it off withtissue paper. Note how effective your cream is as acleanser, and also note how your skin feels afterward.

4. If you were marketing your cream,(a) what name would you give it?(b) what kind of container would you use to package it?(c) what qualities would you promote in youradvertising?

Activity 2Shaving ProductIn general, shaving products are used to prepare theskin for shaving, keep the skin comfortable during theshave, and leave the skin refreshed afterward. Thisactivity involves the preparation of a preshaving lotionfor use with an electric razor, and then of an aftershavelotion.

(A) An Astringent Preshaving Lotion for Use with anElectric RazorThis is an alcoholic lotion whose astrigency will dryand make the skin taut. It also makes the hairs stiff sothat they stand upright.

Procedure1. Weigh the beeswax into the beaker (remember

to choose it according to the type of stirrer beingused).

2. Weigh out the petrolatum (petroleum jelly)onto the disposable weighing pan or watch glass.

3. Weigh out the mineral oil into the 250 ml, glassbeaker.

4. Weigh out the paraffin into the 50 ml, beaker.5. Melt the beeswax on the hot plate and insert the

stirrer. If you are using a metred stirrer, mix at about100-150 rpm.

6. Add the petroleum jelly and stir to blend.7. Add the mineral oil and paraffin and continue to stir.

Adjust the temperature so that all the componentsremain melted or liquid. Computer-animated character used to depict the effect of cosmetics

on the human skin.

Materials (to make 100 g of lotion)1.8 g zinc phenolsulphonate (or lactic acid). This is the

astringent.40.0 g ethyl alcohol (denatured). This is the solvent for

the ingredients.0.1 g menthol. This is used to reduce discomfort.0.1 g camphor. This also helps reduce discomfort.58.0 g witch hazel solution (or perfume + water). If

perfume is used, make sure its scent matches wellwith that of menthol and camphor.

250 mL beakerMagnetic stirrer

Procedure1. Combine all the ingredients in the 250 mL beaker,

and place on the stirrer. Stir until all ingredients havedissolved and a clear solution remains. If perfume oilis used, you may have to add more alcohol to help itdissolve.

2. Bottle and label the product.

Discussion1. Describe the product.2. Put some of the lotion on your hand and wash it

off with water. Note the results and state what typeof product you have made: it is polar if water willwash it off, and nonpolar if not.

3. Feel the skin on your cheeks before applying thelotion. Now put some lotion on your hands, rub themtogether, and rub the lotion on one of your cheeks.Compare the way your skin feels on each cheek.

4. Apply the shaving lotion to one cheek only. Use anelectric razor to. shave the cheek with no lotion andthen repeat the process on the cheek with the lotion.Describe how well the preshave lotion works.

5. If you were marketing your lotion,(a) what name would you give it?(b) what kind of container would you use to packageit?(c) what qualities would you promote in youradvertising?

(B) An Aftershave LotionThe purpose of an aftershave lotion is to relieve thetightness and discomfort caused by shaving. To do this,the product has to refresh and cool the skin, act as amild astringent, soothe minor irritations, and, ifshaving soap was used, neutralize any soap left on theskin.

Materials (to make 100 g of lotion)2.5 g glycerol. This is a humectant that keeps the water

from evaporating.50.0 g ethyl alcohol (denatured).This is a solvent for the

ingredients.0.5 g perfume oil

0.1 g menthol. This is used to reduce discomfort.2.0 g boric acid. This neutralizes the aftereffects of the

soap.44.9 g water. This is a solvent for the ingredients.Methylene blue (optional). This is a coloring for the

lotion.250 mL beakerMagnetic stirrerFunnelFilter paper

Procedure1. Put all the ingredients (except the water) in the 250

mL beaker and place on the stirrer. Start the stirrerand completely dissolve all the ingredients in thealcohol.

2. With the stirrer operating, slowly add the water tothe contents of the beaker. If the water is added tooquickly, the less soluble materials such as the perfumeand menthol may leave the solution.

3. Allow to stand (preferably with chilling) until thepoorly soluble constituents of the perfume oil haveagglomerated, and then filter while the mixture is stillcool.

4. If the lotion is to be colored, add the color solutionafter the mixture is warmed to room temperature,and refilter without further chilling.

5. Bottle and label the product.

Discussion (and testing the product)1. Describe the product.2. Put some of the lotion on your hand and wash it off

with water. Note the results and state what type ofproduct you have made: it is polar if water will washit off, and nonpolar if not.

3. Shave your cheeks in the usual way. Apply theaftershave lotion to one cheek only. Compare the wayyour skin feels on each cheek.

4. If you were marketing your lotion,(a) what name would you give it?(b) what kind of container would you use to package it?(c) what qualities would you promote in youradvertising?

ReferencesBedoukian. P Z. Perfumery and Flavoring Synthetics. NewYork: Elsevier Science Publishing, 1967.

Brown, Keith C., "Chemistry and Cosmetics," Chem 13 News(Number 169), Waterloo, Ont.: University of Waterloo, Apriland May 1987.

James, R. W. Fragrance Technology (Synthetic and NaturalPerfumes). Park Ridge; N.J.: Noyes Data Corporation, 1975.

ObjectivesAfter viewing program 6 and completing this chapter,students should be able to:• Appreciate the fact that modern society depends

onthe development of organic chemicals to improveits way of life;

• Appreciate the fact that modern society has to findsolutions to the problems associated with thedevelopment of organic chemicals;

• Recognize and draw a molecule of an organochloride(DDT), a polychlorinated biphenyl (PCB), achlorophenol (TCP), and a dioxin (2,3,7,8-TCDD);

• Be aware of the importance o£ temperature in theproduction of TCP;

• Describe the reaction involving the formation of2,4,5 -TCP from 1,2,4,5-tetrachlorobenzene andsodium hydroxide;

• Describe the reaction involving the formation of2,3,7,8-TCDD from 2,4,5-TCP;

• Describe the way in which 2,3,7,8-TCDD affects theliver cells in animals,

• Be aware of the problems associated with the disposalof PCBs, TCPs, and dioxins;

• Be aware of the problems associated with the use ofpesticides like DDT and PCB.

Program Description

Program 6 begins by reminding us that humans havealways been trying to improve their life. In this century,organochlorides like DDT and polychlorinatedbiphenyls (PCB) were first developed to make our livesbetter, but their accumulation in animal tissues is nowthreatening to poison us.

More recently, "better" pesticides known aschlorophenols have been developed, but their use alsoposes serious problems. The program illustrates theproduction of one of the chlorophenols, 2,4,5-TCPDuring production, if the temperature is not maintainedat a precise level, an extremely poisonous byproductknown as dioxin or TCDD forms. The 75 differentdioxins now known are all very resistant to breakdown.

An animated sequence then shows how TCDD affectsanimal liver cells: a large increase in liver enzymeproduction results in the subsequent death of theanimal.

Since a so-called acceptable level of TCDD for humanshas yet to be established, we have to make sure thatdioxin sources are strictly controlled. An unwantedbyproduct, dioxins often show up when chlorophenols

are burned in incinerators and are released into the airin the flu gases. Even when the dioxins are collected by"scrubbing" the flu gases, the collected ash is disposedof in landfill sites from which the dioxins make theirway into water supplies, streams, and lakes.

Although dioxins can be broken down at very hightemperatures, this calls for extreme measures andhigher costs - both of which are often subject totaxpayer resistance. This dilemma is not easy to solve,but viewers are reminded that, if society wants thebenefits of organic chemicals, the consequences of theiruse must be accepted as well.

Before Viewing

Well before viewing this program, students should beencouraged to save articles from magazines andnewspapers concerning modern-day use of chemistryand chemicals, and their good or harmful effects. Allthe situations described in the following activities weretaken from such sources. Since situations like thosedescribed here seem to happen regularly, more currentexamples may be substituted for those given below, oradditional examples may be brought up duringclassroom discussions. A brief overview of this questioncould precede the viewing of the program.

After Viewing

After viewing this program, have the students do theactivities. The first one involves dioxins that arediscussed in the program, whereas the second oneposes a different type of environmental problem.

Molecular representation of dioxin formation.

Program 6: Life after Chemistry

ACTIVITIES

Activity 1Dioxin DangerIn the past few years there have been several incidentsinvolving the accidental spillage or burning ofsubstances that either contain or may produce dioxins.This activity asks you to consider two such events.

(A) On the morning of Wednesday, 24 August 1988,3000 residents of St-Basile-le-Grand in the province ofQuebec were evacuated from their homes when smokefrom a burning PCB storage warehouse covered theirtown. Inside the warehouse were 90 000 L of oilcontaining PCBs. This oil had been used by Hydro-Quebec as a coolant in its transformers until thedangers of PCBs became obvious. The owner of thewarehouse had allegedly been ordered to put a fencearound the building, but had not yet done so. Inaddition, the warehouse had no warning signs, safetypatrols, or alarm systems.

While most of the town's residents were evacuated tostay with friends or at hotels, others were allowed toremain in their homes under orders to stay inside, keepthe windows closed, and not drink the water. Still otherresidents slept through the night and found out aboutthe problem only after waking in the morning.

Tests by Environment Canada, Environnement Quebec,and private companies were carried out to determine ifPCBs ended up in the soil and, more importantly, todetermine if dioxins were present. Initial tests showedthe PCB concentration at 13 to 22 times more than theaccepted limits. The dioxins are released by the partialcombustion of PCBs.

Discussion1. Comment on the manner and location in which the

PCBs were stored.2. Quite often, politicians are reluctant to enforce the

laws they themselves have passed regarding thestorage of toxic waste substances. Why do you thinkthis is the case?

3. Some of the residents of St-Basile-le-Grand were toldthey could not stay in their homes, some wereallowed to stay, and others didn't even know therewas a problem. In your opinion, what are the rights o£individuals in a situation like this?

4. Dioxins can form from PCBs when oxygen combineswith the PCBs at high temperatures such as those thatwould occur in a fire like the one described above.Assume the following molecule to be one of the PCBsstored in the warehouse. Complete the equation,showing the dioxin that might form. Use a structuraldiagram to show the dioxin molecule.

cl C1

Figure 4.

5. Research the possible side effects of PCBs even ifdioxins did not form.

(B) It is possible to react phenol with chlorine in such away that all five hydrogens on the aromatic ring arereplaced with chlorine atoms. The resultingcompound, pentachlorophenol, is used to treatlumber to prevent it from being prematurelydestroyed by rot and insects. The Swedishgovernment has now decided to ban this substancebecause, in addition to being a skin irritant, the highheat generated when the wood or sawdust is burnedcauses octachlorodibenzodioxin to form. This is atoxic substance (as all dioxins are), but the problem iscompounded by the fact that octachlorodibenzdioxinis converted by sunlight into the most toxic dioxin ofall - 2,3,7,8-tetrachlorodibenzodioxin - by a processknown as dechlorination.

Discussion1. In the production of pentachlorophenol, the first step

involves the reaction of phenol with three moleculesof C12 to produce 2,4,6-trichlorophenol. Usingstructural formulas for the organic substances, givethe balanced equation for this reaction.

2. The second step in the formation ofpentachlorophenol involves the reaction of2,4,6-trichlorophenol with two molecules of C1 2 in thepresence of FeCl3 catalyst. Using structural formulasfor the organic substances, give the balanced equationfor this reaction.

3. Pentachlorophenol will react under high heat to formoctachlorodibenzodioxin. This occurs when theoxygen on one pentachlorophenol molecule displacesthe chlorine atom adjacent to the hydroxyl on thesecond pentachlorophenol molecule, releasing ahydrogen chloride molecule. This occurs a secondtime between the other hydroxyl group and achlorine atom across from it, causing anotherhydrogen chloride molecule to be released and

octachlorodibenzodioxin to form. This reaction isvery similar to the reaction shown in the programbetween two TCP molecules when2,3,7,8-tetrachlorodibenzodioxin is formed. Usingstructural formulas for the organic molecules, showthe balanced equation for the formation ofoctachlorodibenzodioxin.

4. After the octachlorodibenzodioxin has been releasedinto the air, sunlight causes some of the chlorineatoms to be removed; this results in the formation of2,3,7,8-tetrachlorodibenzodioxin. Using structuralformulas for the organic molecules, show thebalanced equation for the formation of2,3,7,8-tetrachlorodibenzodioxin.

Activity 2The Increase and Decrease ofOzone

Ozone can be a benefit or a problem depending onwhere it is. Close to the earth's surface it is a problembecause of its harmful effect on humans and vegetation.High up in the stratosphere it is a benefit because of theprotection from ultraviolet radiation it offers peopleand plants. This activity considers the two problemscurrently facing society because of the changes in ozoneconcentration that are taking place.

(A) The Increase in OzoneThe ozone increase near the earth's surface can betraced to the use of automobiles. In the car's engine, thehigh temperatures and oxygen-rich conditionsnecessary for complete combustion of the fuel alsocause nitric oxide (NO) to form. This product is inequilibrium with its reactants, but it is usually oxidizedto nitrogen dioxide (N02) before equilibrium can beestablished. This gas is then emitted (along with NOand other products) into the air we breathe.

Once released, the nitrogen dioxide (N02) absorbsultraviolet radiation from sunlight and decomposes togive back nitric oxide (NO) and atomic oxygen or singleatoms of oxygen (0). This atomic oxygen then reactswith the oxygen normally present in the air, and ozone(03) is created.

Ozone is present in our atmosphere from naturalsources such as lightening discharges, and there arereactions that will change it into relatively harmlessproducts. However, during periods of high automobileuse, such as rush hours, ozone concentrations can buildup quite significantly and health problems may result.

These problems include: irritation to the nose, throat,and eyes; breathing difficulties; allergies; a shortenedlife for textiles and rubber products; and damage toplant life, including vegetables.

An example of the seriousness of the situation: a recentair quality report by the Ontario Ministry of theEnvironment stated that, in 1986, ozone levelsexceeded the officially safe limits of 80 ppb (parts perbillion) at 36 of 42 air monitoring stations in theprovince.

Discussion1. Give the balanced equation for the formation of nitric

oxide from nitrogen and oxygen gas in an automobileengine.

2. Give the balanced equation for the formation ofnitrogen dioxide from nitric oxide and oxygen gas inan automobile engine.

3. Give the balanced equation for the formation of nitricoxide and atomic oxygen from nitrogen dioxide afterthe latter has absorbed ultraviolet radiation.

4. Give the balanced equation for the formation ofozone from atomic oxygen and oxygen gas.

5. Gather the following information based on statisticsavailable for your community:• What are the established air quality standards?• What are the main sources of air pollutants• On how many days in the past year was thepollution index reading higher than acceptable?• How do the local authorities respond when smogconditions become dangerously high?• Is data recorded for ozone concentrations on aregular basis?

(B) The Decrease in OzoneIt has been estimated that 550 Canadians will die fromskin cancer this year and another 45 000 will have to betreated for nonmalignant skin cancer caused mainly byoverexposure to the sun. The culprit in both cases is theultraviolet radiation from the sun that passes throughthe atmosphere. Radiation is on the increase becauseozone concentrations in the stratosphere (16-40 kmabove the earth's surface) are being reduced, and ozoneis the substance responsible for absorbing thisradiation.

According to a director of the United StatesEnvironmental Protection Agency, other problemsassociated with this ozone decrease (and subsequentincrease in ultraviolet radiation) include weakenedimmune systems in humans, more respiratory diseases,eye problems, a decrease in world food supplies, andproblems in the oceans due to alterations in the foodchains.

Normally, a self-sustaining chain reaction is at work inthe stratosphere that keeps the ozone (O3)concentration relatively constant. When ultravioletradiation of the appropriate wavelength is absorbed byoxygen (02) molecules, free oxygen atoms are released.These oxygen atoms then react with other oxygenmolecules to produce ozone. This ozone cycle isrepeated as the ozone molecules absorb the ultraviolet(UV) radiation of a different (but equally dangerous)wavelength than that absorbed by the oxygenmolecules. The result of the absorption of the UVradiation by the ozone causes oxygen molecules andatomic oxygen to form. This atomic oxygen recombineswith other oxygen molecules to form more ozone, andthe process continues until something interferes withthe cycle.

The current decrease in ozone concentration has beensudden and dramatic. Estimates vary but, dependingon who is doing the predicting, the global decrease isthought to be from 4 to 8 percent since 1979. Somescientists believe a 1 percent drop in the ozoneconcentration causes a 2 percent increase in surfaceultraviolet radiation. This drop has been caused mainlyby emissions of chlorofluorocarbons (CFCs). This is afamily of volatile, nonflammable, chemically stable,tasteless, and odorless compounds that include CC1 3F,CC12F2, CCIF3, and CHCIF2. These compounds havebeen or are being used as propellants in most aerosolcans, as refrigerants in air conditioners, freezers, andrefrigerators, and as blowing agents in foam plastics.While their use as aerosol propellants has been bannedin the United States since 1978, they are still used forthis purpose in other countries. Once in theatmosphere, CFCs can last for a hundred years beforethey are completely broken down; it is believed that 90percent of all CFCs manufactured are still in theatmosphere.

Discussion1. Give the balanced equation for the formation of

atomic oxygen from oxygen molecules after the latterabsorbs ultraviolet radiation.

2. Give the balanced equation for the formation ofozone from atomic oxygen and oxygen gas.

3. Give the balanced equation for the formation ofatomic oxygen and oxygen molecules from ozonemolecules after the latter absorbs ultravioletradiation.

4. If projections by the experts are correct, by whatrange has the percentage of surface ultravioletradiation increased since 1979?

5. Give the balanced equation for the formation of theCC12F radical and a free Cl atom from a CC13Fmolecule after the latter absorbs ultraviolet radiation.

6. Give the balanced equation for the formation of C10and oxygen gas from ozone and a free Cl atom.

7. Give the balanced equation showing a CIO moleculereacting with a free O atom to form a free Cl atomand oxygen gas.

8. Research the changes brought about by the UnitedNations Environmental Program with respect to theuse and manufacture of CFCs.

ReferencesBaird, N. C., "Photochemical Smog," Chem 13 News ( Number114), Waterloo, Ont.: University of Waterloo, May 1980.

Brady, J.E. and J.R. Holum. Fundamentals of Chemistry, 3rd ed,Toronto: John Wiley and Sons, 1988.

Capindale, J.B. "Organic Chlorine Compounds: A Boon or aCurse?," Chem 13 News (Number 146), Waterloo, Ont.:University of Waterloo, January 1984.

"Organo Chloric Compounds: Insecticides andBacteriocides," Chem 13 News (Number 147), Waterloo, Ont.:University of Waterloo, February 1984.

CFCs that are in the stratosphere absorb UV radiationand the Cl atoms are released one at a time, leavingreactive radicals (like CC12F) that take part in otherreactions. The culprit is the free Cl atom which reactswith ozone (03) and causes disruption of the self-sustaining chain reaction at work in the stratosphere.This happens in two stages: first, the Cl atom combineswith an ozone molecule to form CIO and an oxygenmolecule; and then the CIO combines with a freeoxygen atom (formed when UV radiation breaks anoxygen molecule) to set the Cl atom free again andrelease oxygen molecules. The reaction of one CFCmolecule can lead to the removal of thousands of ozonemolecules since the free Cl atom continues to react andbe set free over and over again.

Dunphy, Catharine, "Is Our Atmosphere Safe?," The TorontoStar, Toronto, Ont.: Saturday, August 13,1988.

Mackay, D. and M. McLachlan, "Toxic Chemicals in the Mistsof Niagara Falls," Chem 13 News ( Number 171), Waterloo,Ont.: University of Waterloo, November 1987.

Pride, Lucy T. Environmental Chemistry-An Introduction.Menlo Park, Calif.: Cummings Publishing Company, 1973.

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