Creative Chemistry Part 11

The chemist is an economizer. It is his special business to hunt up waste products and make them useful. He was, for instance, worried over the waste of the cores and skins and sc.r.a.ps that were being thrown away when apples were put up. Apple pulp contains pectin, which is what makes jelly jell, and berries and fruits that are short of it will refuse to "jell." But using these for their flavor he adds apple pulp for pectin and glucose for smoothness and sugar for sweetness and, if necessary, synthetic dyes for color, he is able to put on the market a variety of jellies, jams and marmalades at very low price. The same principle applies here as in the case of all compounded food products. If they are made in cleanly fashion, contain no harmful ingredients and are truthfully labeled there is no reason for objecting to them. But if the manufacturer goes so far as to put strawberry seeds--or hayseed--into his artificial "strawberry jam" I think that might properly be called adulteration, for it is imitating the imperfections of nature, and man ought to be too proud to do that.

The old-fashioned open kettle mola.s.ses consisted mostly of glucose and other invert sugars together with such cane sugar as could not be crystallized out. But when the vacuum pan was introduced the mola.s.ses was impoverished of its sweetness and beet sugar does not yield any mola.s.ses. So we now have in its place the corn syrups consisting of about 85 per cent. of glucose and 15 per cent. of sugar flavored with maple or vanillin or whatever we like. It is encouraging to see the bill boards proclaiming the virtues of "Karo" syrup and "Mazola" oil when only a few years ago the products of our national cereal were without honor in their own country.

Many other products besides foods are made from corn starch. Dextrin serves in place of the old "gum arabic" for the mucilage of our envelopes and stamps. Another form of dextrin sold as "Kordex" is used to hold together the sand of the cores of castings. After the casting has been made the scorched core can be shaken out. Glucose is used in place of sugar as a filler for cheap soaps and for leather.

Altogether more than a hundred different commercial products are now made from corn, not counting cob pipes. Every year the factories of the United States work up over 50,000,000 bushels of corn into 800,000,000 pounds of corn syrup, 600,000,000 pounds of starch, 230,000,000 pounds of corn sugar, 625,000,000 pounds of gluten feed, 90,000,000 pounds of oil and 90,000,000 pounds of oil cake.

Two million bushels of cobs are wasted every year in the United States.

Can't something be made out of them? This is the question that is agitating the chemists of the Carbohydrate Laboratory of the Department of Agriculture at Washington. They have found it possible to work up the corn cobs into glucose and xylose by heating with acid. But glucose can be more cheaply obtained from other starchy or woody materials and they cannot find a market for the xylose. This is a sort of a sugar but only about half as sweet as that from cane. Who can invent a use for it! More promising is the discovery by this laboratory that by digesting the cobs with hot water there can be extracted about 30 per cent. of a gum suitable for bill posting and labeling.

Since the starches and sugars belong to the same cla.s.s of compounds as the celluloses they also can be acted upon by nitric acid with the production of explosives like guncotton. Nitro-sugar has not come into common use, but nitro-starch is found to be one of safest of the high explosives. On account of the danger of decomposition and spontaneous explosion from the presence of foreign substances the materials in explosives must be of the purest possible. It was formerly thought that tapioca must be imported from Java for making nitro-starch. But during the war when shipping was short, the War Department found that it could be made better and cheaper from our home-grown corn starch. When the war closed the United States was making 1,720,000 pounds of nitro-starch a month for loading hand grenades. So, too, the Post Office Department discovered that it could use mucilage made of corn dextrin as well as that which used to be made from tapioca. This is progress in the right direction. It would be well to divert some of the energetic efforts now devoted to the increase of commerce to the discovery of ways of reducing the need for commerce by the development of home products. There is no merit in simply hauling things around the world.

In the last chapter we saw how dextrose or glucose could be converted by fermentation into alcohol. Since corn starch, as we have seen, can be converted into dextrose, it can serve as a source of alcohol. This was, in fact, one of the earliest misuses to which corn was put, and before the war put a stop to it 34,000,000 bushels went into the making of whiskey in the United States every year, not counting the moonshiners'

output. But even though we left off drinking whiskey the distillers could still thrive. Mars is more thirsty than Bacchus. The output of whiskey, denatured for industrial purposes, is more than three times what is was before the war, and the price has risen from 30 cents a gallon to 67 cents. This may make it profitable to utilize sugars, starches and cellulose that formerly were out of the question. According to the calculations of the Forest Products Laboratory of Madison it costs from 37 to 44 cents a gallon to make alcohol from corn, but it may be made from sawdust at a cost of from 14 to 20 cents. This is not "wood alcohol" (that is, methyl alcohol, CH_{4}O) such as is made by the destructive distillation of wood, but genuine "grain alcohol" (ethyl alcohol, C_{2}H_{6}O), such as is made by the fermentation of glucose or other sugar. The first step in the process is to digest the sawdust or chips with dilute sulfuric acid under heat and pressure. This converts the cellulose (wood fiber) in large part into glucose ("corn sugar") which may be extracted by hot water in a diffusion battery as in extracting the sugar from beet chips. This glucose solution may then be fermented by yeast and the resulting alcohol distilled off. The process is perfectly practicable but has yet to be proved profitable. But the sulfite liquors of the paper mills are being worked up successfully into industrial alcohol.

The rapidly approaching exhaustion of our oil fields which the war has accelerated leads us to look around to see what we can get to take the place of gasoline. One of the most promising of the suggested subst.i.tutes is alcohol. The United States is exceptionally rich in mineral oil, but some countries, for instance England, Germany, France and Australia, have little or none. The Australian Advisory Council of Science, called to consider the problem, recommends alcohol for stationary engines and motor cars. Alcohol has the disadvantage of being less volatile than gasoline so it is hard to start up the engine from the cold. But the lower volatility and ignition point of alcohol are an advantage in that it can be put under a pressure of 150 pounds to the square inch. A pound of gasoline contains fifty per cent. more potential energy than a pound of alcohol, but since the alcohol vapor can be put under twice the compression of the gasoline and requires only one-third the amount of air, the thermal efficiency of an alcohol engine may be fifty per cent. higher than that of a gasoline engine. Alcohol also has several other conveniences that can count in its favor. In the case of incomplete combustion the cylinders are less likely to be clogged with carbon and the escaping gases do not have the offensive odor of the gasoline smoke. Alcohol does not ignite so easily as gasoline and the fire is more readily put out, for water thrown upon blazing alcohol dilutes it and puts out the flame while gasoline floats on water and the fire is spread by it. It is possible to increase the inflammability of alcohol by mixing with it some hydrocarbon such as gasoline, benzene or acetylene. In the Taylor-White process the vapor from low-grade alcohol containing 17 per cent. water is pa.s.sed over calcium carbide. This takes out the water and adds acetylene gas, making a suitable mixture for an internal combustion engine.

Alcohol can be made from anything of a starchy, sugary or woody nature, that is, from the main substance of all vegetation. If we start with wood (cellulose) we convert it first into sugar (glucose) and, of course, we could stop here and use it for food instead of carrying it on into alcohol. This provides one factor of our food, the carbohydrate, but by growing the yeast plants on glucose and feeding them with nitrates made from the air we can get the protein and fat. So it is quite possible to live on sawdust, although it would be too expensive a diet for anybody but a millionaire, and he would not enjoy it. Glucose has been made from formaldehyde and this in turn made from carbon, hydrogen and oxygen, so the synthetic production of food from the elements is not such an absurdity as it was thought when Berthelot suggested it half a century ago.

The first step in the making of alcohol is to change the starch over into sugar. This transformation is effected in the natural course of sprouting by which the insoluble starch stored up in the seed is converted into the soluble glucose for the sap of the growing plant.

This malting process is that mainly made use of in the production of alcohol from grain. But there are other ways of effecting the change. It may be done by heating with acid as we have seen, or according to a method now being developed the final conversion may be accomplished by mold instead of malt. In applying this method, known as the amylo process, to corn, the meal is mixed with twice its weight of water, acidified with hydrochloric acid and steamed. The mash is then cooled down somewhat, diluted with sterilized water and innoculated with the mucor filaments. As the mash molds the starch is gradually changed over to glucose and if this is the product desired the process may be stopped at this point. But if alcohol is wanted yeast is added to ferment the sugar. By keeping it alkaline and treating with the proper bacteria a high yield of glycerin can be obtained.

In the fermentation process for making alcoholic liquors a little glycerin is produced as a by-product. Glycerin, otherwise called glycerol, is intermediate between sugar and alcohol. Its molecule contains three carbon atoms, while glucose has six and alcohol two. It is possible to increase the yield of glycerin if desired by varying the form of fermentation. This was desired most earnestly in Germany during the war, for the British blockade shut off the importation of the fats and oils from which the Germans extracted the glycerin for their nitroglycerin. Under pressure of this necessity they worked out a process of getting glycerin in quant.i.ty from sugar and, news of this being brought to this country by Dr. Alonzo Taylor, the United States Treasury Department set up a special laboratory to work out this problem. John R. Eoff and other chemists working in this laboratory succeeded in getting a yield of twenty per cent. of glycerin by fermenting black strap mola.s.ses or other syrup with California wine yeast. During the fermentation it is necessary to neutralize the acetic acid formed with sodium or calcium carbonate. It was estimated that glycerin could be made from waste sugars at about a quarter of its war-time cost, but it is doubtful whether the process would be profitable at normal prices.

We can, if we like, dispense with either yeast or bacteria in the production of glycerin. Glucose syrup suspended in oil under steam pressure with finely divided nickel as a catalyst and treated with nascent hydrogen will take up the hydrogen and be converted into glycerin. But the yield is poor and the process expensive.

Food serves substantially the same purpose in the body as fuel in the engine. It provides the energy for work. The carbohydrates, that is the sugars, starches and celluloses, can all be used as fuels and can all--even, as we have seen, the cellulose--be used as foods. The final products, water and carbon dioxide, are in both cases the same and necessarily therefore the amount of energy produced is the same in the body as in the engine. Corn is a good example of the equivalence of the two sources of energy. There are few better foods and no better fuels. I can remember the good old days in Kansas when we had corn to burn. It was both an economy and a luxury, for--at ten cents a bushel--it was cheaper than coal or wood and preferable to either at any price. The long yellow ears, each wrapped in its own kindling, could be handled without crocking the fingers. Each kernel as it crackled sent out a blazing jet of oil and the cobs left a fine bed of coals for the corn popper to be shaken over. Driftwood and the pyrotechnic fuel they make now by soaking sticks in strontium and copper salts cannot compare with the old-fashioned corn-fed fire in beauty and the power of evoking visions. Doubtless such luxury would be condemned as wicked nowadays, but those who have known the calorific value of corn would find it hard to abandon it altogether, and I fancy that the Western farmer's wife, when she has an extra batch of baking to do, will still steal a few ears from the crib.

XI

SOLIDIFIED SUNSHINE

All life and all that life accomplishes depend upon the supply of solar energy stored in the form of food. The chief sources of this vital energy are the fats and the sugars. The former contain two and a quarter times the potential energy of the latter. Both, when completely purified, consist of nothing but carbon, hydrogen and oxygen; elements that are to be found freely everywhere in air and water. So when the sunny southland exports fats and oils, starches and sugar, it is then sending away nothing material but what comes back to it in the next wind. What it is sending to the regions of more slanting sunshine is merely some of the surplus of the radiant energy it has received so abundantly, compacted for convenience into a portable and edible form.

In previous chapters I have dealt with some of the uses of cotton, its employment for cloth, for paper, for artificial fibers, for explosives, and for plastics. But I have ignored the thing that cotton is attached to and for which, in the economy of nature, the fibers are formed; that is, the seed. It is as though I had described the aeroplane and ignored the aviator whom it was designed to carry. But in this neglect I am but following the example of the human race, which for three thousand years used the fiber but made no use of the seed except to plant the next crop.

Just as mankind is now divided into the two great cla.s.ses, the wheat-eaters and the rice-eaters, so the ancient world was divided into the wool-wearers and the cotton-wearers. The people of India wore cotton; the Europeans wore wool. When the Greeks under Alexander fought their way to the Far East they were surprised to find wool growing on trees. Later travelers returning from Cathay told of the same marvel and travelers who stayed at home and wrote about what they had not seen, like Sir John Maundeville, misunderstood these reports and elaborated a legend of a tree that bore live lambs as fruit. Here, for instance, is how a French poetical botanist, Delacroix, described it in 1791, as translated from his Latin verse:

Upon a stalk is fixed a living brute, A rooted plant bears quadruped for fruit; It has a fleece, nor does it want for eyes, And from its brows two wooly horns arise.

The rude and simple country people say It is an animal that sleeps by day And wakes at night, though rooted to the ground, To feed on gra.s.s within its reach around.

But modern commerce broke down the barrier between East and West. A new cotton country, the best in the world, was discovered in America. Cotton invaded England and after a hard fight, with fists as well as finance, wool was beaten in its chief stronghold. Cotton became King and the wool-sack in the House of Lords lost its symbolic significance.

Still two-thirds of the cotton crop, the seed, was wasted and it is only within the last fifty years that methods of using it have been developed to any extent.

The cotton crop of the United States for 1917 amounted to about 11,000,000 bales of 500 pounds each. When the Great War broke out and no cotton could be exported to Germany and little to England the South was in despair, for cotton went down to five or six cents a pound. The national Government, regardless of states' rights, was called upon for aid and everybody was besought to "buy a bale." Those who responded to this patriotic appeal were well rewarded, for cotton rose as the war went on and sold at twenty-nine cents a pound.

[ILl.u.s.tRATION: PRODUCTS AND USES OF COTTONSEED]

But the chemist has added some $150,000,000 a year to the value of the crop by discovering ways of utilizing the cottonseed that used to be thrown away or burned as fuel. The genealogical table of the progeny of the cottonseed herewith printed will give some idea of their variety. If you will examine a cottonseed you will see first that there is a fine fuzz of cotton fiber sticking to it. These linters can be removed by machinery and used for any purpose where length of fiber is not essential. For instance, they may be nitrated as described in previous articles and used for making smokeless powder or celluloid.

On cutting open the seed you will observe that it consists of an oily, mealy kernel encased in a thin brown hull. The hulls, amounting to 700 or 900 pounds in a ton of seed, were formerly burned. Now, however, they bring from $4 to $10 a ton because they can be ground up into cattle-feed or paper stock or used as fertilizer.

The kernel of the cottonseed on being pressed yields a yellow oil and leaves a mealy cake. This last, mixed with the hulls, makes a good fodder for fattening cattle. Also, adding twenty-five per cent. of the refined cottonseed meal to our war bread made it more nutritious and no less palatable. Cottonseed meal contains about forty per cent. of protein and is therefore a highly concentrated and very valuable feeding stuff. Before the war we were exporting nearly half a million tons of cottonseed meal to Europe, chiefly to Germany and Denmark, where it is used for dairy cows. The British yeoman, his country's pride, has not yet been won over to the use of any such newfangled fodder and consequently the British manufacturer could not compete with his continental rivals in the seed-crushing business, for he could not dispose of his meal-cake by-product as did they.

[Ill.u.s.tration: Photo by Press Ill.u.s.trating Service

Cottonseed Oil As It Is Squeezed From The Seed By The Presses]

[Ill.u.s.tration: Photo by Press Ill.u.s.trating Service

Cottonseed Oil As It Comes From The Compressors Flowing Out Of The Faucets

When cold it is firm and white like lard]

Let us now turn to the most valuable of the cottonseed products, the oil. The seed contains about twenty per cent. of oil, most of which can be squeezed out of the hot seeds by hydraulic pressure. It comes out as a red liquid of a disagreeable odor. This is decolorized, deodorized and otherwise purified in various ways: by treatment with alkalies or acids, by blowing air and steam through it, by shaking up with fuller's earth, by settling and filtering. The refined product is a yellow oil, suitable for table use. Formerly, on account of the popular prejudice against any novel food products, it used to masquerade as olive oil. Now, however, it boldly competes with its ancient rival in the lands of the olive tree and America ships some 700,000 barrels of cottonseed oil a year to the Mediterranean. The Turkish Government tried to check the spread of cottonseed oil by calling it an adulterant and prohibiting its mixture with olive oil. The result was that the sale of Turkish olive oil fell off because people found its flavor too strong when undiluted. Italy imports cottonseed oil and exports her olive oil. Denmark imports cottonseed meal and margarine and exports her b.u.t.ter.

Northern nations are accustomed to hard fats and do not take to oils for cooking or table use as do the southerners. b.u.t.ter and lard are preferred to olive oil and ghee. But this does not rule out cottonseed.

It can be combined with the hard fats of animal or vegetable origin in margarine or it may itself be hardened by hydrogen.

To understand this interesting reaction which is profoundly affecting international relations it will be necessary to dip into the chemistry of the subject. Here are the symbols of the chief ingredients of the fats and oils. Please look at them.

Linoleic acid C_{18}H_{32}O_{2} Oleic acid C_{18}H_{34}O_{2} Stearic acid C_{18}H_{36}O_{2}

Don't skip these because you have not studied chemistry. That's why I am giving them to you. If you had studied chemistry you would know them without my telling. Just examine them and you will discover the secret.

You will see that all three are composed of the same elements, carbon, hydrogen, and oxygen. Notice next the number of atoms in each element as indicated by the little low figures on the right of each letter. You observe that all three contain the same number of atoms of carbon and oxygen but differ in the amount of hydrogen. This trifling difference in composition makes a great difference in behavior. The less the hydrogen the lower the melting point. Or to say the same thing in other words, fatty substances low in hydrogen are apt to be liquids and those with a full complement of hydrogen atoms are apt to be solids at the ordinary temperature of the air. It is common to call the former "oils" and the latter "fats," but that implies too great a dissimilarity, for the distinction depends on whether we are living in the tropics or the arctic. It is better, therefore, to lump them all together and call them "soft fats" and "hard fats," respectively.

Fats of the third order, the stearic group, are called "saturated"

because they have taken up all the hydrogen they can hold. Fats of the other two groups are called "unsaturated." The first, which have the least hydrogen, are the most eager for more. If hydrogen is not handy they will take up other things, for instance oxygen. Linseed oil, which consists largely, as the name implies, of linoleic acid, will absorb oxygen on exposure to the air and become hard. That is why it is used in painting. Such oils are called "drying" oils, although the hardening process is not really drying, since they contain no water, but is oxidation. The "semi-drying oils," those that will harden somewhat on exposure to the air, include the oils of cottonseed, corn, sesame, soy bean and castor bean. Olive oil and peanut oil are "non-drying" and contain oleic compounds (olein). The hard fats, such as stearin, palmitin and margarin, are mostly of animal origin, tallow and lard, though coconut and palm oil contain a large proportion of such saturated compounds.

Though the chemist talks of the fatty "acids," n.o.body else would call them so because they are not sour. But they do behave like the acids in forming salts with bases. The alkali salts of the fatty acids are known to us as soaps. In the natural fats they exist not as free acids but as salts of an organic base, glycerin, as I explained in a previous chapter. The natural fats and oils consist of complex mixtures of the glycerin compounds of these acids (known as olein, stearin, etc.), as well as various others of a similar sort. If you will set a bottle of salad oil in the ice-box you will see it separate into two parts. The white, crystalline solid that separates out is largely stearin. The part that remains liquid is largely olein. You might separate them by filtering it cold and if then you tried to sell the two products you would find that the hard fat would bring a higher price than the oil, either for food or soap. If you tried to keep them you would find that the hard fat kept neutral and "sweet" longer than the other. You may remember that the perfumes (as well as their odorous opposites) were mostly unsaturated compounds. So we find that it is the free and unsaturated fatty acids that cause b.u.t.ter and oil to become rank and rancid.

Obviously, then, we could make money if we could turn soft, unsaturated fats like olein into hard, saturated fats like stearin. Referring to the symbols we see that all that is needed to effect the change is to get the former to unite with hydrogen. This requires a little coaxing. The coaxer is called a catalyst. A catalyst, as I have previously explained, is a substance that by its mere presence causes the union of two other substances that might otherwise remain separate. For that reason the catalyst is referred to as "a chemical parson." Finely divided metals have a strong catalytic action. Platinum sponge is excellent but too expensive. So in this case nickel is used. A nickel salt mixed with charcoal or pumice is reduced to the metallic state by heating in a current of hydrogen. Then it is dropped into the tank of oil and hydrogen gas is blown through. The hydrogen may be obtained by splitting water into its two components, hydrogen and oxygen, by means of the electrical current, or by pa.s.sing steam over spongy iron which takes out the oxygen. The stream of hydrogen blown through the hot oil converts the linoleic acid to oleic and then the oleic into stearic. If you figured up the weights from the symbols given above you would find that it takes about one pound of hydrogen to convert a hundred pounds of olein to stearin and the cost is only about one cent a pound. The nickel is unchanged and is easily separated. A trace of nickel may remain in the product, but as it is very much less than the amount dissolved when food is cooked in nickel-plated vessels it cannot be regarded as harmful.

Even more unsaturated fats may be hydrogenated. Fish oil has. .h.i.therto been almost unusable because of its powerful and persistent odor. This is chiefly due to a fatty acid which properly bears the uneuphonious name of clupanodonic acid and has the composition of C_{18}H_{28}O_{2}.

By comparing this with the symbol of the odorless stearic acid, C_{18}H_{36}O_{2}, you will see that all the rank fish oil lacks to make it respectable is eight hydrogen atoms. A j.a.panese chemist, Tsujimoto, has discovered how to add them and now the reformed fish oil under the names of "talgol" and "candelite" serves for lubricant and even enters higher circles as a soap or food.

This process of hardening fats by hydrogenation resulted from the experiments of a French chemist, Professor Sabatier of Toulouse, in the last years of the last century, but, as in many other cases, the Germans were the first to take it up and profit by it. Before the war the copra or coconut oil from the British Asiatic colonies of India, Ceylon and Malaya went to Germany at the rate of $15,000,000 a year. The palm kernels grown in British West Africa were shipped, not to Liverpool, but to Hamburg, $19,000,000 worth annually. Here the oil was pressed out and used for margarin and the residual cake used for feeding cows produced b.u.t.ter or for feeding hogs produced lard. Half of the copra raised in the British possessions was sent to Germany and half of the oil from it was resold to the British margarin candle and soap makers at a handsome profit. The British chemists were not blind to this, but they could do nothing, first because the English politician was wedded to free trade, second, because the English farmer would not use oil cake for his stock.

France was in a similar situation. Ma.r.s.eilles produced 15,500,000 gallons of oil from peanuts grown largely in the French African colonies--but shipped the oil-cake on to Hamburg. Meanwhile the Germans, in pursuit of their policy of attaining economic independence, were striving to develop their own tropical territory. The subjects of King George who because they had the misfortune to live in India were excluded from the British South African dominions or mistreated when they did come, were invited to come to German East Africa and set to raising peanuts in rivalry to French Senegal and British Coromandel.

Before the war Germany got half of the Egyptian cottonseed and half of the Philippine copra. That is one of the reasons why German warships tried to check Dewey at Manila in 1898 and German troops tried to conquer Egypt in 1915.

But the tide of war set the other way and the German plantations of palmnuts and peanuts in Africa have come into British possession and now the British Government is starting an educational campaign to teach their farmers to feed oil cake like the Germans and their people to eat peanuts like the Americans.

The Germans shut off from the tropical fats supply were hard up for food and for soap, for lubricants and for munitions. Every person was given a fat card that reduced his weekly allowance to the minimum. Millers were required to remove the germs from their cereals and deliver them to the war department. Children were set to gathering horse-chestnuts, elderberries, linden-b.a.l.l.s, grape seeds, cherry stones and sunflower heads, for these contain from six to twenty per cent. of oil. Even the blue-bottle fly--hitherto an idle creature for whom Beelzebub found mischief--was conscripted into the national service and set to laying eggs by the billion on fish refuse. Within a few days there is a crop of larvae which, to quote the "Chemische Zentralblatt," yields forty-five grams per kilogram of a yellow oil. This product, we should hope, is used for axle-grease and nitroglycerin, although properly purified it would be as nutritious as any other--to one who has no imagination.

Driven to such straits Germany would have given a good deal for one of those tropical islands that we are so careless about.