October 1990

Poison Ivy If scratching doesn’t spread it, what does? Itchy myths shattered! 4

MysteryMatters The Fox River Fish Kill 6 Thousands of fish were dead. The neighbors were raising a stink. The scientists investigating it were stumped.

Light Your Candy Get some wintergreen candies...put a little sparkle in your mouth! 10 The Phantom Flame A chemistry student transforms a common assignment into a metaphor for science. 13

The Back Burner Friedrich Wöhler’s Lost Aluminum 14 Shiny, cheap, useful aluminum is around us, everywhere. Wasn’t it always?

The Puzzle Page The Margarine Puzzle 16 What common substance is added to margarine to lower the calorie count? pOisoN IVY

By Eric Witzel Dormant, not dead Urushiol is actually a mixture of four It was a pleasant sunny afternoon, different but similar phenolic com­ and I was helping my father stack pounds called catechols, which con­ firewood. Some of the logs had con­ sist of a benzene ring with two venient handle-like vines that had hydroxyl (-OH) groups on grown firmly onto the tree. I grasped adjacent carbons them to carry the logs, blithely igno­ and a 15-carbon side rant of the type of vines they were. I chain (Figure 1). The paid for that ignorance. The next day catechols in urushiol are rela- I developed the red, itching rash that tively small, stable organic~~ ...~·­ comes from touching poison ivy compounds. Because vines-and so learned that the irritat­ they are stable, any ing agent in poison ivy remains active article that becomes con- '. long·after the plant is dead. In fact, I taminated with urushiol later learned that even 100-year-old should be washed to specimens in botanical collections make sure that it doesn't can cause a rash. spread the irritant.

Poison ivy belongs to the Picking up a rake two I. Anacardiaceae or cashew family, months after it was which includes many other rash­ used to rid a garden of poison ivy can causing plants such as poison oak cause a rash. Contaminated articles and poison sumac. Poison ivy is should be washed thoroughly native to North America and unfortu­ because the amount of urushiol on a nately is widespread. Equally unfortu­ pinhead would be enough to cause nate, the plant defies easy identifica­ rashes in 500 people. tion. The leaves do appear in groups Urushiol is one of the most com­ of three, which gave rise to the mon causes of allergic reactions in woodsman's old warning: "When the United States. The rash is leaves are three, let it be." However, caused by the immune system, the surface of the leaves may be whose normal function is to destroy either hairy or shiny, and their edges p9tentially lethal microbes such as may be either toothed or smooth. bacteria, fungi, and viruses. The sys­ All parts of the poison ivy plant tem recognizes the microbes in part produce the oily irritating agent, because they contain very large urushiol (OR-oo-shee-ol). To elicit a molecules. The catechols in urushiol rash, urushiol must touch the skin do not, by themselves, trigger the directly. Luckily, the irritant is not immune system because their volatile (and so does not evaporate molecules are so small. readily) and is released only when the plant is disturbed. Unluckily, it Ten-minute warning does not take much of a disturbance You can avoid getting a rash by to release the oil. Simply brushing washing your skin soon after expo­ against the plant is enough. It is also sure with lots of plain, cold water. possible for droplets of urushiol to be Avoid using soap because it removes carried through the air on particles of natural oils that help protect the skin, smoke. Inhaling urushiol smoke can and warm water only spreads the severely damage breathing pas­ urushiol further. Gasoline and other sages. My older sister was once hos­ organic solvents are not recommend­ pitalized after walking downwind of a ed because they also spread the oil. brush fire in an area where poison ivy Ten minutes after exposure, this fat­ grew. soluble irritant penetrates the outer TINAMION 4 CHEM MAnERS, OCTOBER 1990 BenadrylTM) reduce the itching, and calamine lotion and hydrogen perox­ ide dry out oozing blisters. The popu­ lar CaladrylTM combines calamine and Benadryl. For severe rashes, doctors may prescribe cortisone, giv­ ing it in pills or injections. The only certain way of avoiding poison ivy rash is to avoid the plant. 3-n-Pentadecadienyicatecllo! However, this is impossible for peo­ ple who must venture into poison ivy­ OH infested areas, and the U.S. Forest Service estimates that at any given time about 10% of its employees are Figure 1. several compounds are pre­ on sick leave because of exposure to sent in urushiol, the irritating oil exud­ poison ivy or poison oak (in general, ed by polson ivy. poison ivy grows in the eastern layer of skin and binds to proteins on states, poison oak in the western the surface of cells in deeper layers. states). Soon there may be ways of The combined urushiol-protein protecting people against urushiol. molecules are large enough to trigger For instance, researchers have found the immune system. The deep skin that swallowing small amounts of cells internalize and modify the urushiol makes people less sensitive urushiol-protein complexes (for to the irritant, and their allergic reac­ example, enzymes cut pieces off the tions are milder and less frequent. protein), and then the modified com­ Also, people may soon be able to plex returns to the surface of the cell. protect themselves against urushiol There, an urushiol complex is bound by using an aerosol spray called Ivy­ by an immune system cell called a Block. Developed for the Forest helper T cell, which then divides Service, Ivy-Block contains activated rapidly and produces many copies of bentonite clay, a mineral used in itself. These T-cells release proteins antiperspirants that can absorb called Iymphokines that attract anoth­ enough water to increase its volume er type of immune system cell called several fold. Besides forming a pro­ macrophages, which in turn cause an tective barrier between skin and inflammatory syndrome that includes urushiol, bentonite binds the oily irri­ swelling, redness, itching and, in tant so it can't penetrate the skin. severe cases, a rash of oozing blis­ FDA approval of Ivy-Block is pend­ ters. Contrary to popular belief, these ing. blisters do not contain urushiol, so The next time I stacked firewood scratching them will not make the at my parents' home, you can be rash spread. However, scratching sure I was on the lookout for suspi­ does increase the likelihood of infec­ cious vines. I also wore gloves and tion and should be avoided. washed my hands. This time, I escaped getting that awful itchy rash. Itching for treatment Although there is no way to cure a Eric Witzel is a former high school chem­ poison ivy rash, you can ease the istry teacher and former editorial intern at discomfort. Ice packs soothe the Chern Matters. He now works as a research assistant at the University of inflamed skin, over-the-counter medi­ Maryland's Center ofMarine cations (such as hydrocortisone Biotechnology in Baltimore where he is creams and the antihistamine studying chemotaxis in marine bacteria.

CHEM MATIERS, OCTOBER 1990 5 Fox River Fish Kill oxygen, which is commonly found as Dead wrong a cause of a fish kill." Could it be pesticides and herbicides By Harvey Black Usually low levels of dissolved washing into the river from a nearby oxygen can be recognized just golf course? The section of the city The fish were dying, by the tens, before sunrise. "The reason is," said bordering the river is a filled-in wet­ hundreds, thousands. No one knew Ball, ''there is plenty of dissolved oxy­ land. Could some long-forgotten toxic why. Experts at the Wisconsin gen during the day, when algae are material, used as part of the fill, now Department of Natural Resources busy using sunlight in photosynthe­ be leaking into the river? Were there (DNR) were scratching their heads, sis. At night the plants are taking barrels rusting on the river bottom, unable to explain why the dead stur­ back the oxygen (emitted during pho­ 20 or so feet below the surface, with geon, white bass, walleye, and other tosynthesis), and threatening the fish poisons oozing into the water? In fish were floating on a three-mile with suffocation." But the scientific fact, Ball said, recently a barrel con­ stretch of the Fox River that flows sleuths discovered no lack of dis­ taining chemical residue had been through the city of Oshkosh. This solved oxygen in the water. found floating in the river. stretch of river links Lake Winnebago 'We had no idea what to look for," A number of storm sewers dis­ and Lake Butte des Morts. said Ball. "Any of a thousand things charge into the river. Had a "midnight Solving the mystery would mean might be doing it." countless hours of tracking down, and "finally discarding, all the plausi­ ble explanations and eventually set­ tling on an explanation that the scien­ tific literature seemed to rule out. According to Joe Ball, a DNR water resources specialist, there had been fish kills on that stretch of river for about 30 years. One or two major kills had occurred annually. Ball explained that fish kills are not terri­ bly unusual. They're often the result of natural causes, such as the stress of spawning or a lack of dissolved oxygen in the water; the latter can be caused by an overabundance of algae or decaying plants. But in 1986 the frequency and severity of the die-...... offs increased so noticeably that th~e...•...... J.i/.•. DNR began to investigate. :f

"People were starting to think 4. J •.". i there was something going on here '_.it..~ besides natural factors," Ball said. The kills would typically go on for between one and three days, then stop. The largest kill occurred just after Memorial Day weekend in 1988, when an estimated 30,000 white bass and sheepshead died. A kill that size meant something unnatural was going on, explained Ball. "There shouldn't be that many fish dying in this section of the river, especially since monitoring hadn't indicated any problem with dissolved

6 CHEM MATTERS, OCTOBER 1990 I _MA1JEnS~ _

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When Wisconsin officials suspected that the fish kills in the Fox River might be caused by the effluent from the Oshkosh Sewage Treatment Plant, they conducted a practical test. Here, a Department of Natural resources worker lowers a cage of live fish into the river near the effluent discharge point.

dumper" been toxic But this wasn't a novel. There was breathe easier but not the people motn"",ic into trlern'? What about bio· something harmful in the environ· who lived near the river. The dead "iI"ti,-,n? Were insect lanfae ment, and the DNR had to find it. fish stank and they weren't pretty to f""",,,,t;,,1'1 on contaminated sediments Attention focused on the Oshkosh look at. The public wanted an end to becoming poisoned food fOi sewage treatment plant, which dis­ the mess. Were the fish infected with charges its waste into this section of harmful bacteria or virus? the river, because large numbers of Last chance rYt,,"'tOr\/ novel, there were anum· dead fish appeared just downstream With just about every explanation of plausible explanations. Bail from the plant. Furthermore, accord­ examined and rejected, the scientists ch€!ckEJd them all. ing to Ball, low levels of chlorine turned their attention to the testing "We were testing the water. We used to treat the waste can be toxic facility of a major outboard motor cor­ testing the sediment. We were to fish. poration. It is located across the river numerous water samples and "We were able to detect concen­ from the sewage treatment plant, a analyzing for toxic organic com­ trations of chlorine in the water that few hundred yards downstream. pounds and toxic metals. We were were borderline," Ball continued. To "It was a process of elimination," also testing the fish," Ball explained. check out this possibility, cages of said Ball. "After doing a lot of analy­ The intensive work continued live fish were hung directly in the sis, taking a lot of samples, and com­ through the summers of 1986, 1987, path of the plant's discharge. "The ing up with zeros for everything, we and the spring of 1988. And, as in a fish survived. We totally eliminated finally started looking at that plant." good mystery novel, the plausible the sewage treatment plant as hav­ According to Ball, the firm tests as leads, one by one, turned into blind ing anything to do with the fish kills," many as a dozen prototype motors at alleys. The tests were all negative. said Ball. The plant's operators could a time. Mounted on boats that are

CHEM MATTERS. OCTOBER 1990 7 tethered along the shore, they can collectively burn as much as 4,000 gallons of gas a day and generate up to 3,000 horsepower. Focusing on the testing facility raised a new set of questions. What could the motors be putting in the water? What kind of tests were need­ ed to examine these compounds? According to Ball, researchers had examined the effects of outboard motors on the environment, but both industry and independent findings White bass were brought to the laboratory to test the hypothesis of carbon monoxide poisoning. After the gas was bubbled into the water, blood was with· showed no reason to be concerned. drawn from the fishes' hearts, and the degree of carbon monoxide saturation was Nevertheless, officials at the DNR measured with a specialized spectrometer. examined the scientific literature to see what was coming out of the request. He wanted me to take a oxygen were bound up with carbon exhaust pipes of the motors. Volatile stab at ruling out carbon monoxide monoxide instead. The control fish organic compounds were one prod­ poisoning in fish." showed less than 10%. Ecker uct. But Ball said they ''were nowhere Ecker said he had never heard of thought the results showed the car­ near lethal levels for fish." the possibility that fish could suffer bon monoxide hypothesis was "on to from carbon monoxide poisoning. something." Cold-blooded victims When Ball told Ecker of another fish "I usually look at human blood, Eventually the search narrowed the kill, the chemist got ready to test the where we see fatalities at anywhere possible culprit to carbon monoxide. fish blood for carbon monoxide. In a from 30% to 90% [CO concentra­ A product of incomplete combustion, sense Ecker was flying blind. The tion]," he said. CO is a colorless, odorless gas. And instrument he used was a CO­ Because of the newness of these it can be lethal. If inhaled, it attaches Oximeter, a standard instrument findings, Ecker was not satisfied with itself to the hemoglobin molecule in used to test for CO in human blood. one test. He used the palladium the blood, preventing this molecule The CO-Oximeter measures the reduction method to confirm the from doing its job of carrying Iife­ transmission of light wavelengths results (see Chern Matters, Dec. giving oxygen to the tissues. Carbon through blood, allowing investigators 1984). This involves using acid to monoxide not only takes the place of to determine the percent of oxyhe­ decompose the carbon oxygen but also forms a much tighter moglobin, carboxyhemoglobin, total monoxide-hemoglobin bond. The bond to hemoglobin than does oxy­ hemoglobin, and oxygen content released carbon monoxide is trapped gen. The result is suffocation (see (Figure 1). But Ecker said no one in a solution containing a palladium "Pumping Oxygen," Chern Matters, had tested fish blood for this com­ compound. The palladium, as a February 1984). pound before, so there were no stan­ result, changes from its ionic state to As a possible culprit, carbon dards of judgment. its metallic form. monoxide brought along its own Ball brought the samples of fish "A mirror tends to form," explained share of problems. For one thing, blood to the lab. Ecker tested control Ecker. "You have metal formed at the Ball said, there is no convenient way samples-fish not exposed to carbon surface of the liquid that looks like a to test for it in water. Second, it's not monoxide. He compared those mirror. The more carbon monoxide, very soluble in water and disperses results with tests of blood from fish the more of this is formed." rapidly into the air, so it appears killed in the infamous stretch of the There were other tests. Ball said unlikely that fish would take it up. Fox River. carbon monoxide was injected into a "We had looked at everything "I got significant differences," said tank of live fish. The fish died quickly. else," explained Ball. Ecker. The blood of the fish that were Caged live fish were placed at a site "I got a call from Joe Ball," killed showed a 60-70% saturation of near the outboard motor tests in the remembered Tom Ecker, a chemist carbon monoxide, which means that Fox River. A similar cage was placed at the Wisconsin State Laboratory of 60-70% of the hemoglobin at a control site. In eight hours the Hygiene, "and he had this weird molecules that would normally carry fish near the test site were either

8 CHEM MAnERS, OCTOBER 1990 dead or dying. Their blood carbon monoxide saturation was between 50% and 80%. The control fish were healthy. "As scientists, we were sure-as sure as you can possibly get-that carbon monoxide was responsible for killing the fish," asserted Ball. Finding that carbon monoxide was responsible for the fish kills meant more than solving a mystery. It helped teach a valuable lesson: Use caution in interpreting the scientific literature. As both Ecker and Ball said, previous experiments had Red shown that carbon monoxide was not a threat to fish. 500 600 "Scientists are taught you Wavelength (nm) shouldn't have to reinvent the wheel," said Ecker. "We're told to go to the literature. " Figure 1. When light is passed through blood, some of it Is absorbed. The amount But it's important to be alert to the absorbed depends on the color of the light and the chemical condition of the limitations of past experiments and blood. The black line on the graph shows the absorbance spectrum of blood that note how the phenomenon being is saturated with oxygen; the colored line Is blood saturated with carbon monox­ investigated differs from the pub­ ide. A computerized spectrometer known as the CO-Oximeter measured the spec­ trum of blood samples taken from the dead fish and calculated the percentage of lished experiments. O2 and CO in the samples. As both Ecker and Ball pointed out, the Fox River situation differed from published reports because in into the water. With the installation of that system the Fox River immense amounts of When the DNR presented its find­ in the spring of 1989, the problem carbon monoxide were being forced ings to the firm, its environmental and appears solved. No fish kills were into the water by powerful propellers safety director said he was surprised reported in the summer of 1989 in (outboard motors vent their exhaust at the results. He declined to discuss that once-deadly stretch of the Fox underwater because the water muf­ the matter further because of lawsuits River. In July 1990, the company paid fles the noise). When this was com­ over the cost of the fish kills. But a the state of Wisconsin $40,000 in bined with higher water temperatures company-hired consultant verified the penalties for the fish kill. They also in the summer, the fish were more findings, though he said, "When I first paid $20,000 to finance a study of susceptible to the CO's lethal effects. heard the suspicion [that the CO was fish in the Fox River. Ball said that when water tempera­ responsible for the fish kills], I If you're worried about outboard ture increases, the metabolism of fish laughed. It was so far out. ..." He, motors on lakes threatening fish with does also, but the amount of oxygen too, declined further comment carbon monoxide poisoning, you can in the water decreases. Consequently, because of the lawsuits. relax. Both Ball and Ecker say the the fish pump more water-in this In light of the findings, the compa­ testing facility is unique in the force instance laden with carbon monox­ ny installed an exhaust venting sys­ with which it injected large amounts ide-through their gills. tem. Now the outboard motors are of gas into a small stretch of the river. But why did the fish kills suddenly attached to a system of pipes, which The amount put into lakes by normal increase in the last few years? The prevents the carbon monoxide from outboard motors is generally so small company's test facility has been there getting into the water. The pipes carry and the lakes are so large that there for nearly 30 years. Ball said that the exhaust gases directly from the is little to be concerned about. company recently had started running motors to a stack, where they are dis­ Harvey Black is a science writer for more powerful motors, meaning more persed into the air high above the News and Information Service, University carbon monoxide was being injected city. of Wisconsin, Madison, WI.

CHEM MAnERS, OCTOBER 1990 9 LIGHT YOUR CANDY By Linda M. Sweeting

Would you like to really amaze your friends? Gather some sugar cubes, wintergreen candies, and adhesive tape, and take them (along with your friends) into a room with no windows, such as a closet or bathroom. Turn out the lights and wait about five or 10 minutes. During that period, your eyes will begin to adapt to the dark­ ness, and you may begin to be able to see a little of your surroundings. Take two sugar cubes and strike one against the other as if you were try­ ing to strike a match. If your eyes are sufficiently adapted to the dark, you will see a bluish white glow from the sugar cubes when you strike them. Now for the candy. The best way to see the candy is in your mouth. Keeping your mouth open, place the candy between your teeth and (unless your dentist forbids it) bite down and crush the candy. Your friend will see blue light coming from your mouth. If a friend is not avail­ Figure 1. When you crush a Wint-O-Green Lifesaver it gives off a burst of blue light. able, use a mirror. If you don't see You can see this demonstration of triboluminescence only if you first let your eyes adapt to a dark room. anything, try again, being careful not to let the candy get wet. The flash of professional scientists. energy when standing on stair two, light from the candy is usually To understand triboluminescence, more potential energy when on stair brighter than the one from the sugar let's look at how atoms and three, but you can't have the energy cube. The tape? Watch closely while molecules emit light, a phenomenon that's midway between these you quickly pull a few inches of it that was first explained by Niels because there is no stair 2 1/2. After from the roll. Bohr. If you supply a lot of energy to electrons are transported up the atoms, for example by heating them energy "stairs" by heat or electricity, Rubbing for light in a flame or by passing electricity they are able to go back to the lowest This fascinating phenomenon has through them, they emit light of a energy (the ground floor) by steps. been known for centuries and has color that is characteristic of the kind As they cascade down the steps, the several names: triboluminescence of atom. If the spectrum of the light is energy they lose is released as light (from the Greek tribein, to rub), examined to determine the primary whose color is determined by the mechanoluminescence, and fractolu­ colors that compose the light, it is size of the step. minescence. The last part of the found to consist of sharp, colored Molecules behave the same way name, luminescence, means "light lines, that is, very specific wave­ except that the steps are closer emission." Once you break the lengths. Bohr explained these sharp together and wiggling (like a rope names down, they aren't so mysteri­ lines by proposing that electrons in ladder) and so they emit many col­ ous: we have light emission from rub­ atoms have only certain allowed ored lines that are so close together bing, mechanical action, or fracture. potential energies, just as you are that we often cannot separate them I've been studying this phenomenon allowed to have only certain energies readily into individual colors. Our for several years, with help from and positions when you are standing eyes are able to see only a small undergraduate students and other on stairs. You can have potential fraction of the light that atoms and

10 CHEM MATTERS, OCTOBER 1990 molecules emit, namely, that between violet (big, high-energy steps) and red (smaller steps). Light we cannot see is called ultraviolet (the high-energy emissions that cause sunburn) and infrared (that we can detect as heat). Lightning in your mouth Where does the light from sugar and candy come from? The first clue is in the spectrum of the light from sugar - it is exactly the same as the spec­ trum of lightning. Lightning is simply an electrical current (electrons) pass­ ing through air, exciting (giving ener­ gy to) the nitrogen molecules of the air. It appears that triboluminescence is lightning on a very small scale. When a sugar crystal is cracked into two pieces, each has an electrical charge, one positive and the other negative (Figure 2A). When there is II a big enough charge accumulation (voltage), the electrons jump through the air, colliding with and exciting the nitrogen molecules. Most of the light emitted by the nitrogen in the air is ultraviolet, at an energy too high for our eyes to detect; thus the emission appears faint. But why is the emission from the candy so much brighter? In addi­ tion to the sugar (sucrose) in candy, flavoring has been added. Some fla­ vorings are themselves luminescent. Given enough energy, wintergreen molecules will emit light too, and their LORI SESKIN-NEWMAN emission is mostly in the visible region of the spectrum (Figure 2B). Because they are not in the air but in A"gure 2. When a Wint-o-Green Lifesaver is cracl

CHEM MAnERS, OCTOBER 1990 11 ---...... -..,...... , • - -__...... - ....,-.--.. , _...... 10_.....__ , ..__or-...._...... , lIJIIO_·_lUYl__-___..... _ , __CIlI '""l- ~ _ "'"_lIp.-.o: I _~"'<-O_'- "'_

FRIEDRICH WOHLER'S This was the first synthesis of an LOST ALUMINUM organic compound from inorganic substances. The result was the first By Benjamin M. Gimarc step in the downfall of Vitalism, the doctrine that the origin and phenome­ Several years ago I was elected to na of life are due to or produced by a serve a term as chairperson of the vital principle, as distinct from purely chemistry department at the chemical or physical forces. For University of South Carolina. As I example, it was believed that com­ moved my things into the new office, pounds characteristic of living organ­ I looked through the desk drawers of isms (such as urea-the principal my predecessor and came across an compound in urine) could be made compared to 776 oC for KCI). Davy old cardboard box containing a fold­ easily by animals but couldn't be syn­ suspected that there was an undis­ ed piece of paper. Opening the first thesized in the lab. Wohler's synthe­ covered metallic element in the min­ fold revealed a message, written by sis of urea was the first step in the erai alumina and, in 1807, tried to hand and iron-brown with age: unification of organic and inorganic separate the element from the miner­ chemistry as aspects of the same aI. Even though he failed to isolate "Aluminum foil from Wohler. science. the element he gave it the name alu­ Don't open it in the wind." In 1827, Wohler was the first per­ minum. Other Europeans adopted son to prepare aluminum metal in the variation aluminium, but Ameri­ Inside were a few small scraps of pure form and to describe its chemi­ cans still use Davy's original spelling aluminum foil. Who was Wohler, I cal properties. He made aluminum by and pronunciation. In 1825 in Copen­ wondered, and what was so impor­ reacting aluminum chloride with hagen, H.C. Oersted reported the tant about these fragments of such a potassium metal: preparation of aluminum by reacting common material? I decided to look AICl with a mixture of potassium and AICl + 3K -. AI + 3KCI s into it. s iron. What he obtained was not pure Today aluminum is almost part of Potassium was a costly substance aluminum but an alloy or metal mix­ the natural landscape. Indeed, alu­ ture. When Wohler heard of Oerst­ minum is the most abundant metal in because it had to be produced elec­ trolytically, using an electric current ed's work, he repeated it using pure the Earth's crust. Its principal ore, potassium and obtained a small ?auxite, contains alumina (AI 0 ) and generated from other expensive 2 s chemicals in a voltaic cell. amount of pure aluminum in the form IS found on every continent. The electrolytic method of separa­ of a gray powder. By 1845, Wohler Friedrich Wohler (1800-1882) was was making metallic aluminum parti­ a German chemist who studied tion of a compound into its compo­ nent elements was pioneered in the cles that he described as being big ~edicine at Marburg and Heidelberg early 19th century by Sir Humphry as pinheads. In 1854, Henri St. Claire In Germany and chemistry under Deville, Professor of the Ecole Nor­ Berzelius at Stockholm, Sweden. Davy, an English chemist, who had isolated the metals potassium, sodi­ male in Paris, improved Wohler's About 1825 Wohler began teaching method and produced lumps of alu­ at a technical school in Berlin. In um, calcium, barium, boron, magne­ sium, and strontium by electrolysis. minum the size of marbles. He 1831 he took a university post at reduced the cost somewhat by using Cassel, then moved to Gottingen The electrolytic separation of potassi­ um from one of its salts, say KCI, sodium metal instead of potassium in where he stayed until he retired in the reaction with aluminum chloride. 1880. He is best remembered for his requires passage of an electric cur­ rent through molten KCI: He also succeeded in producing alu­ preparation in 1828 of urea from minum by the electrolysis of molten ammonium chloride and lead(lI) electric current aluminum chloride. cyanate: 2KCI (molten) .. Better than the crown jewels ~ 2K (molten) + CI (gas) 2NH4CI + Pb(OCNb 2 Deville's work caught the attention of ammonium lead(lI) chloride cyanate The electrolytic method seemed to Napoleon III of France who financed be impractical for aluminum com­ further study of aluminum and its

2H2NCONH2 + PbCI 2 pounds because their melting points methods of preparation. Napoleon urea lead(lI) are almost inaccessibly high (the had dreams of lightweight helmets chloride melting point of AI20 s is 2000 oC, and armor for his armies, but the first

14 CHEM MAnERS, OCTOBER 1990 and cryolite, Na3AIFs, has a lower melting point than either alumina or cryolite has separately - just as a mixture of ice and salt melts (or freezes) at a lower temperature than either does independently. The alu­ mina in the molten A1203-Na3AIF6 mixture could then be electrolyzed to produce pure aluminum metal. As production of the metal became more efficient, the price of a pound of alu­ minum fell from $545 in 1852 to $115 in 1855, to $7 in 1886, and to $0.70 in 1900. Napoleon III, emperor of France, ordered a set of spoons made from alu­ Forgotten foil minum because it was more This information was interesting, but precious than silver or gold. it didn't solve the mystery of the alu­ Today, aluminum sells for minum foil fragments in my new 1/10,OOOth the price of gold. desk. Were they really made by Wohler? How did they get to South Carolina? Clearly, they were more the size of Wohler's pinheads than Deville's lumps. If our specimen did come from Wohler, as claimed by the aged handwriting, we can date it to between 1845 and 1880; it's probably closer to the earlier date, when he was still interested in aluminum. Wohler's laboratory in Gottingen was a popular destination for American article fashioned from aluminum was at $1.1 0 per oz- the largest piece of chemists who went to Germany in a baby rattle made for the emperor's aluminum that had ever been cast. the 19th century for advanced study. son. Aluminum was too expensive for Before its installation, it was dis­ Perhaps one of Wohler's American everyday use but luxury goods soon played at Tiffany's in New York. students returned home with a sou­ followed, including a set of forks and The production of aluminum venir of his year's study abroad. spoons used by honored dignitaries depended either directly or indirectly (lesser guests of the emperor had to on the production of an electric cur­ Benjamin M. Gimarc teaches chemistry suffer with tableware of gold or sil­ rent for electrolysis. Davy's electricity and does research in theoretical chem­ ver). Napoleon III presented his came from voltaic cells made of zinc istry at the University ofSouth Carolina, Columbia, SC. cousin, the King of Denmark, with an and copper, expensive materials that aluminum helmet. The public got its meant high costs for electrolytically References first view of aluminum when bars of produced elements. The electric gen­ Cowles, A. The True Story ofAluminum; H. the new metal were exhibited along erator was invented in 1866, permit­ Regnery: Chicago,1958. with the French crown jewels at the ting the conversion of steam or water Hofmann, A.W.v. "Friedrich Wohler," in Great Paris Exposition of 1855. In the power into electricity. This lowered Chemists, E. Farber, Ed.; Interscience: New United States, the first bars of alu­ the price of electrolytic separations, York, 1961; p. 507. minum were produced in 1856 by but the big advance came in 1886 Alfred Mounier of Camden, NJ, and when Charles Hall in the United Richards, J.W. Aluminum: Its History, Occur­ rence, Properties, Metallurgy, and Applica­ were exhibited at the Franklin States and Paul Heroult in France tions, Including Its Alloys; H.C. Baird; Philadel­ Institute in Philadelphia. When the independently devised a process that phia, 1890. Washington Monument was complet­ freed aluminum electrolytically from Van Klooster, H.S. "Friedrich Wohler and His ed in 1884, its apex was capped with the alumina in bauxite ore. Hall and American Pupils," J. Chem. Educ. 1944, 21, a solid aluminum tip weighing 100 oz Heroult found that a mixture of AI20 3 158.

CHEM MATTERS, OCTOBER 1990 15 THE MARGARINE PUZZLE By Donald Glover with Kenneth Kolb Bradley University, Peoria, IL When I walked into the kitchen my wife, who was baking a cake, asked, "Don, can you melt a tablespoon of margarine while I get the other ingre­ dients?" But when I heated some Fleischmann's Light margarine it didn't behave properly. Naturally, I had ignored the warning on the pack­ age that said "Do not use use for cooking." "You're a chemist," my wife said. "What's going on here?" I didn't have an answer, so I went to the gro­ cery store where I found Fleischmann's regular margarine, Fleischmann's Light margarine with 20% fewer calories, and Fleischmann's Extra Light margarine with 50% fewer calories. I wondered how they could keep lowering the calories in a product that's mostly fat. The ingredient list on the labels offered a clue, so I bought a pound of each and took them back to our labo­ ratory. My colleague, Ken, put one serv­ ing (14 grams) of each kind of mar­ garine in a separate test tube, immersed the three tubes in warm water, and we waited. The margarine quickly melted, and after about 15 minutes the liquid separated into two layers. The fat (actually partially hydrogenated vegetable oil) rose to the top while a layer of water settled to the bottom. And in each test tube there were different amounts of fat and oil. There was the answer! The regular margarine is 21% water, the low calo­ rie variety is 43% water, and the extra low calorie is 57% water. The manu­ facturer reduced the calories simply by adding water! When I checked the sales receipt I got another surprise. The regular margarine sold for $1.19 per pound, the ligHt for $1.29, and the Extra Light for $1.69. I hadn't real­ ized that water is so expensive! What is the percentage of water in real butter? How much is in your mar­ garine? Test them and see for your­ self!

16 CHEM MAnERS, OCTOBER 1990