1938: Chemistry

The progress characteristic of chemistry, so noticeable in the last decade, continued during 1938. Some of the most difficult problems, as they appeared but a few years ago, have been solved, but with each new bit of established knowledge there comes a realization that, while much has been accomplished, after all relatively little is known.

Vitamins.

It seems only yesterday that the scientific world was wondering just what a vitamin might be. Enough had been learned to establish its vital place as an accessory food factor, but its nature and structure were quite baffling. This constituted something of a challenge, and a number of our most brilliant research men undertook to establish the missing information. This led to the identification, isolation, and purification of one vitamin after another; and the one designated B₁ is now manufactured synthetically on a commercial basis and at a price lower than can be realized for material of equal potency derived from natural sources.

During the year, vitamin K. the diet factor necessary for coagulation of blood, has been isolated in crystals. The source was an alfalfa meal oil, and the material is expected to have an important bearing in those fields of surgery which involve hemorrhage.

A highly purified form of vitamin A was prepared — a preparation so concentrated that it is almost fifteen thousand times more potent than ordinary medicinal cod liver oil. This was accomplished by a method involving special absorbing materials prepared from carbon and magnesia. The greater part of the impurities in fish liver oil are first removed by freezing them out, and the residue is then treated to prepare this substantially pure vitamin A.

It was also discovered that vitamin C. the substance in fresh fruits and vegetables which prevents and cures scurvy, is probably formed by plants and animals from a fatty substance, though the vitamin itself belongs to the sugar and starch group of chemicals. This further step in obtaining understanding of the chemical nature of the vitamin is doubtless one which will lead to its ultimate synthesis.

An unexpected use of vitamin A has been discovered in industry. In one factory where household appliances are decorated with white enamel, it is necessary to match carefully the several parts to prevent mixing whites that are a trifle bluish with those that have a yellow tinge. The same problem presents itself in many other industries and those who are engaged in color-matching develop fatigue, eyestrain, and headache. It was suggested that color inspectors exhausted the visual purple in their eyes. This is the chemical believed to be responsible for vision, and its production is helped by vitamin A. The eyes of color inspectors were tested with the biophotometer, and shortages of visual purple were found. The daily use of capsules of carotene, a vitamin A raw material, has caused color-matchers' eyestrain to disappear; and the efficiency of color-matching promptly increased by more than 75 per cent.

Hormones.

Another difficult field which is yielding valuable results through research is that of hormones, which have been found to be as essential to plants as they are to animals. Here, too, synthesis and exact identification through research have furthered the work; and now it is found that organic chemicals like trimethylamine, which is present in many plants and animals, may have a physiological action like that of a sex hormone. The plant hormones have been used successfully to promote rooting of cuttings and even leaves in greenhouses, something important to the nurseryman, and also to promote pollination by dusting or spraying.

Fuels.

In the field of applied chemistry, competition for first place in interest is keen among fuels, textiles, synthetic resins, and the scores of new chemicals that have been introduced during 1938.

There is a striking contrast between the plans of Russia to build trucks to operate on gas generated on the truck itself from wood picked up as it goes along through forests and sparsely settled country, and the plans for the wide exploitation of a new petroleum refining process here in the United States. The operation of trucks, buses, and some automobiles by gases produced from wood and charcoal is not a new thing in Europe; but to depend upon whatever fuel may be found along the roadside, as in the remote areas where gasoline is unobtainable in Russia, is new.

Here, eleven plants are under construction to operate a new cracking process which will enable not only the production of maximal requirements of aviation gasoline from very cheap crude oil, but in fact to make whatever derived products may be in greatest demand. The petroleum industry is faced with widely varying seasonal demands, and the ordinary process yields a number of by-products along with gasoline. With this new process, the refinery breaks down the large molecules of crude oil and reforms the oil in smaller ones of the right size and type to make the fuel desired. The importance of such new processes is emphasized when viewed in the light of research results which indicate that, if gasoline could be produced of a certain configuration of molecule and at a low enough price, it would meet the need for greatly increased driving power. For instance, it is believed that a gasoline molecule with a 7-atom carbon chain would be greater in power than a molecule with a 6-atom line. A hydrocarbon known as 2-2-3 trimethylbutane has more potential power than dynamite, but unfortunately at present it costs about $3,600 per gallon. Further research and development may change that picture at any time.

The petroleum industry continues to go chemical. The majority of the new compounds offered for the textiles, the lacquer, and the synthetic resin industry are made synthetically from gases derived from petroleum. The acetone market was upset a short time ago by the appearance of lower-cost materials derived from petroleum; and now a similar possibility confronts the glycerol (glycerin) industry, itself a by-product of the soap industry.

It was announced that for more than a year a commercial plant had been operating, producing a high-grade glycerol at low cost from petroleum gases; and there seems to be no limit on the quantity that may be produced. This may become of great importance in time of emergency. It is produced from allyl chloride as the starting point. From that is manufactured 1-2-3 trichloropropane.

In a sense the isoöctane which is used in millions of gallons in aviation is a synthetic chemical from petroleum gases and was made possible only by pains-taking research in organic chemistry. The manufacture of alcohols, glycols, ketones, esters, ethers, acetylene, acetic acid, etc., are other products from the utilization of petroleum as a chemical raw material. Furthermore, aromatic hydrocarbons of the toluol type may now be made from the aliphatic hydrocarbons, in which class petroleum belongs. This means that we are no longer dependent on coal tar as the source of chemicals of great use in peace and essential in times of war.

Another fuel of growing importance is the oil used in diesel engines. The rapidity with which these engines are being adopted for all sorts of power purposes is little realized. One of the difficulties has been slow starting. It is reported that a product derived from crude turpentine makes possible a Diesel engine fuel characterized by quick starting and anti-knock. From the crude turpentine, pine oil is derived. When this is reacted with elemental sulphur, the result is a sulphurized terpene. The addition of from one to two per cent of this sulphurized terpene produces the quick-igniting, anti-knock Diesel fuel.

The drilling of oil wells has its chemical phase. Troubles are encountered in deep well-drilling because of the caving in or heaving of the shales, softened by drilling fluid and under the extreme earth pressures of great depths. It has been found that the caving in or filling up of the oil hole can be greatly retarded, if not prevented, by the use of a drilling fluid rich in silicate of soda, commonly called water glass, and sodium chloride, which is common salt.

Textiles.

Turning to textiles and textile fibers, it may be more exciting at the moment to visualize a solid gold gown as within the realm of possibility, but the promise of practically wear-proof hosiery appears the more practical. The gold gown is within reach because of a discovery that gossamer fabrics can be covered with a film of gold less than 1/10,000 of an inch thick at a cost of about $2.50 a yard. An organic compound of gold which breaks up into its constituent parts when slightly heated, leaving a thin film of metal deposited on the fabric like a dye, is the key to the process. A garment of, say, six yards of material would have an amount of metal less in bulk than a ten cent piece, yet uniformly distributed along all the fibers of the fabric.

The really important announcement of the year is that of the perfection of an organic polymer covered by two patents and named Nylon. This is a coined word and is the generic name for all materials defined scientifically as synthetic fiber-forming polymeric amides, having a protein-like chemical structure; derived from coal, air and water, or other substances, it is characterized by extreme toughness and strength and the peculiar ability to be formed into fibers and into various shapes such as bristles, sheets, etc. We will hear much of nylon for many years to come. The first commercial form is the bristle now used in a widely advertised toothbrush. These bristles do not lose their stiffness, nor do they break into slivers, as often happens with natural bristles.

The first commercial unit for the manufacture of nylon fiber is just being started. Nylon is impressive, for in it we have another example of a somewhat unexpected result of fundamental research. It is the second commercial result of a program of fundamental research in organic chemistry begun about 1938 for the purpose of establishing data missing from the literature, and without immediate commercial objectives. Work on the production of organic compounds through polymerization has brought these gratifying results. Furthermore, they are the fruits of group research under competent leadership and not examples of individual accomplishments, though the work centers on the far-reaching discoveries of the group leader.

The nylon fiber has greater elasticity, remarkable recovery after stretching, tensile strength of a high order, and can be produced in fibers far smaller and yet stronger than natural silk. Dyeing offers no difficulties, and the resistance to abrasive wear is little short of marvelous. On one test, a pair of nylon stockings was worn for twenty days with sandals in beach sand, and at the end of that time no appreciable wear was indicated. It can readily be seen that fiber of such characteristics promises to serve a real need in knitted wear of all sorts, including gloves and other garments that are subjected to abrasive action, repeated stretching, and other severe service.

There is another new fiber of promise on the horizon, namely Vinyarn, which will be produced in textiles as soon as a new plant can be erected. Its basis is vinyl acetate, and the ultimate raw materials are acetylene and chlorine.

Improvements have been made in cellulose acetate, Teca (being the trade name of a fiber with a permanent crimp) making possible new effects in various ways. The direct spinning of fiber from alpha cellulose, without going through the viscose process — the principal benefit of which is to change the physical rather than the chemical form of the basic cellulose — is also being perfected, and the first commercial unit put in operation.

A mechanical development effecting some improvements in the strength of the material is the basis of a new plant producing rayon by a continuous process from the viscose, at a rate which represents an important saving in time, and consequently in production costs.

Rayon staple continues to gain in popularity and presents a paradox. Here is a fiber made from cellulose derived from wood, reduced to short uniform lengths, worked on cotton machinery, and producing a fabric that has the appearance and feel of wool. Rayon has entered another field as special cord for passenger-car tires, with records which clearly indicate such cords to be superior to the cotton cords we have known. Here the competition is sharp, with a new cotton cord prepared with a treatment intended to make it also resistant to the high temperatures developed in long non-stop runs of heavy vehicles.

A somewhat different class of textiles is prepared from such protein materials as casein derived from milk and from soybeans. While at the moment uneconomic under American conditions, nevertheless the subject has received attention here. One group in the United States has taken the first steps in producing a fiber from casein which makes it possible to use practically any grade of the raw material, whereas the Italian fiber is more restricted in this respect. Some interesting results have been obtained with soybean protein, and in Japan it is reported that such fiber is about to be produced commercially. From Holland comes the report that bacteria which are able to destroy proteins of the casein class succeeded in completely destroying such synthetic fibers, and this may prove a deterrent to the commercial development of such goods in countries where wool is easily accessible.

Cellulose Wrapping Films.

To the growing list of moisture-proof wrapping films must be added a new class — clear, moisture-proof, and water-insensitive material. In wrapping dairy products, moisture loosens the wax backing of the ordinary cellulose film and soon renders it unfit for service. This is why most butter is still wrapped in waxed paper and not in transparent film. It has been found that a slight etherification of the cellulose film causes wax-coating compositions to adhere to the extent necessary. Some of the resulting films withstand a month of actual immersion in water before disintegration.

Transparent Resins.

Lignin, the principal waste in the manufacture of pulp from wood, has long been the subject of intensive research. It has been used experimentally for the production of a binding resin important in the possible utilization of sawdust and waste wood, but its dark color was a handicap. It has now been found that, by hydrogenation under heat and pressure, the resin becomes transparent, thus opening entirely new fields for investigation. Byproducts of this research include a new compound which appears suitable as a lacquer solvent and as a wood preservative and certain others which may be employed as thickening and toughening agents for varnish.

Metal Plating.

Metal plating, so long employed in many industries, was improved during 1938. Brighter silver deposits are obtained through the use of two organic chemical compounds, thiourea and methylamine. A high-speed process for copper plating was introduced. This involves special salts and anodes; and the result is a smooth, bright, heavy coating of cyanide copper applied in one fourth the time required in present commercial practices. The absence of pitting, of hydrogen, and of noxious fumes are important.

Then an electrolytic process was announced which, without the use of dyes or pigments, can produce almost any desired shade or color on a metallic surface. The various colors are produced in one plating bath, the composition of which is not changed, for the color produced is a function of the plating time. As the amount of plate increases, the color changes in repetitive cycles of violet to blue to green to yellow to red. Variations of color are rendered possible by prior plating with other metals such as copper or nickel.

Molybdenum.

In view of the Far Eastern situation, it is important to note that tungsten, once dominated by China as a source (large deposits of tungsten ore occurring in Southern China), is losing its position to molybdenum, three fourths of which is produced in the United States. It is cheaper than tungsten, and research has shown that it can be used in many places where heretofore tungsten has had preference.

Chinawood or Tung Oil.

The interference with export of tung oil from China and the announced intention of Japanese interests to control the tung nut and oil industry makes more important the success in this country in the production of Chinawood or tung oil. Many of the trees set out a few years ago in the South are coming into bearing; and the production of high-grade oil from these nuts is expected to reach about 4,000,000 lb. in 1938, in contrast to 2,000,000 lb. produced in 1937. Our normal imports are 150,000,000 lb.

Synthetic Resins.

In the field of synthetic resins, where the United States has been a pioneer, progress was notable in 1938. Ethyl cellulose became available in commercial quantities. A new cellulose acelobutyrate was offered, and polyvinyl acetyl plastic sheet made its bow. The acetobutyrate is of low moisture absorption and consequent increased resistance to warping, which has been one of the failings of earlier cellulose acetate plastics. The polyvinyl acetyl, while suitable for use as a plastic cement for materials such as thermo-setting resins and metals, is expected as a resin to be particularly useful as a safety-glass plastic. It is a clear, transparent thermoplastic resin.

Methyl methacrylate (trade name, Lucite) attracted attention as a reflector to mark the edge of highways when lighted by automobile headlights. It was also employed in dental and other surgery to illuminate otherwise inaccessible areas. Light introduced at one end of a rod is transmitted practically 100 per cent, there being no loss through side walls.

Protective Coatings.

The use of resins to bond laminated wood, to improve varnishes and protective coatings for both wood and metal, and to impart non-creasing and other characteristics to textiles was further developed during the year. (See above, Transparent Resins.)

Among the new uses for these and other flexible resins is insulation where low voltages are concerned. The resins are extruded on the wire; and at least one of them resists breaking from repeated flexing, even after the wire itself has been broken by this method.

Lacquers, including synthetic resins, have found extensive use for coating the inside of various containers, and to this list must now be added a thermoplastic coating which resists acids, alkalis, and alcohols. It imparts no odor, taste, or deleterious effect even to foodstuffs and finds application also where sulphuric acid, liquid acids, formaldehyde, and concentrated hydrogen peroxide are to be held.

Research for new uses for silver had led to experiments with this metal as a coating. A lacquer based on methyl methacrylate plastic has been prepared for chromium metal decoration to protect it against exposure and subsequent rusting due generally to too thin a coating or to pinholes in the plate.

Cigarette Paper.

Although the United States manufactures by far the majority of cigarettes consumed in the world, the paper has always been imported. The erection of a mill at Brevard. N. C., marks the first full-scale commercial enterprise to make this paper in the United States. The flax will be obtained in the North and the Northwest. The location of the mill was determined to a large extent by the availability of an adequate supply of very pure water.

Newsprint Paper.

The announcement was also made that the long-expected mill for the production of white newsprint from Southern woods would be erected beginning in 1939. While there has been a great expansion of paper-making in the South, the product is the well-known kraft paper.

Naval Stores.

The year's advances in naval stores include the preparation of a non-crystalizing gum rosin to overcome a serious problem presented in such industries as adhesives, core oil, soap, and paper sizing, where the ordinary variety has frequently caused difficulty. Another is hydrogenated rosin.

Mold and Rope Inhibitor.

Among the reagents to combat the lower organisms must be added Mycobane, which is a mold and rope inhibitor for inclusion with ingredients used in breadmaking. This substance effectively increases the amount of propionates present and thus causes an increased inhibitory effect.

Synthetic Rubber-like Products.

In the field of synthetic materials with rubber-like properties, advances have been made in both increased output and improved quality of neoprene and Thiokol, which are American products. Abroad, great emphasis has been placed on new varieties of Buna, the synthetic rubber-like product of Germany now produced at the rate of from 20,000 to 25,000 metric tons per annum. It is interesting that, while great claims are made for this product, the importation of natural rubber continues even though there is a 100 per cent import duty upon it, the revenue thus realized being used for the construction of further plants for the manufacture of the synthetic material.

Separators.

It is said that each generation lives on the waste piles of the preceding one. This is not universally true, but with the knowledge that certain natural resources are irreplaceable, processes such as the one called sink-and-float, whereby values can be more easily obtained from waste, are significant. This process permits the separation of one or more of the components of a mixture, such as coal and minerals, where specific gravity lies between 1 and 3. The parting liquids used are synthetic organic materials such as pentachlorethane and tetrabromomethane. The process employs pre-treatment with an active agent solution which immunizes the material from the heavy liquids. The process has been demonstrated success-fully on waste piles, principally coal, heretofore regarded as a total loss.

Liquid chlorine is being used on an increased scale: and the delicate mechanisms employed to deliver it to water treatment chlorinators are sometimes obstructed by impurities seldom present in excess of 0.20 per cent. However, this has led to the development of a method whereby impurities have been reduced to 0.01 per cent, thus eliminating the difficulty.

Wetting Agents.

The list of surface active, or wetting, agents has been materially extended; and those made and sold commercially in the United States comprise a list of more than 150. These are used as detergents, as dispersing agents, for wetting and emulsifying, and as penetrants. They are in demand in the textile, laundry, leather and paper industries; they are employed in insecticides, in fruit washing, in the manufacture of pigments, metal cleaning, electroplating, embalming penetrants, and in lubrication. For the most part they are synthetic materials and their number grows as research goes forward in organic chemistry.

Fertilizers.

In the fertilizer field there is some pride in the fact that the American situation is changed from one of 100 per cent importation of the salts of potassium for plant foods to the recent organization of an association for the export of these same potash salts. National sufficiency in a material of this kind is of great importance.

A semi-granular fertilizer compound containing 42 per cent urea nitrogen for use in mixed fertilizers is now available. The urea is synthesized in a grade of highest purity and also serves as a raw material for one of the synthetic resins. For the latter use, such an impurity as iron can be present in no more than a few parts per million.

Soilless Agriculture.

The interest in hydroponies, or soilless agriculture, has been maintained. The harvesting of the fourth crop from such an installation on Wake Island, to provide fresh vegetables for maintenance men and Pacific Clipper passengers and crew, has contributed to this interest. The process is particularly suited to such an isolated community, for high yields of vegetables can be grown in surprisingly small areas. Wake Island's area is too small for ordinary farming, and the expense of shipping food supplies is so great as to give hydroponics an economic advantage.

Results of New Method for Whipping Cream.

During the latter part of 1937 there was introduced a method of whipping cream in which steel siphon bottles of cream are charged with nitrous oxide under pressure. Whipped cream as ordinarily made depends upon mechanical action only as a means of entrapping gases in the form of bubbles within the cream. In this new device, the cream when discharged through a small valve is instantly whipped because the gas is less soluble at the lower pressure. Production has now exceeded a million units annually and has doubled the production of nitrous oxide in this country. The nitrous oxide has no detrimental effect upon the cream.

Clay Bentonite Film.

One of the interesting developments in the field of pure chemistry is a film of the clay bentonite which is coherent, self-supporting, and flexible, without the use of any binder. To what extent it can be developed commercially is yet to be determined, but the material shows excellent electric properties and is comparable with first grade natural mica. There are several industries where it may be a welcome contribution.

Chemistry and Medicine.

The advances in the borderland between chemistry and medicine and always of great importance. Some time ago it was shown that nicotinic acid was a specific for the cure or prevention of black tongue in dogs. The same material has now been shown to be a cure for pellagra in humans, and the rapidity with which severe cases have recovered has caused great interest among the medical profession. The disease has followed various economic disasters in the South. Nicotinic acid is a constituent of the vitamin B₂-complex and for sixty years has been known as one of the chemical constituents of nicotine. It was only a year ago that it was found, in one of the most brilliant discoveries, to be the very drug for which suffering humanity in the South and other parts of the world had been waiting.

Among the synthetic products, ephedrine must now be included. This drug has heretofore been imported from China and has assumed considerable importance in modern therapy.

The remarkable effects in the treatment of many infections with sulfanilamide has attracted much research; and after experiences with hundreds of derivatives, physicians have predicted that one day all infections diseases may be brought under control through the use of such compounds. One relative of sulfanilamide gives some promise as a remedy in some pneumonia cases, and sulfanilamide itself is now finding a new use in treatment of blindness resulting from trachoma. Sodium sulfonyl sulfonylate has been used to cure distemper in animals, and so becomes the first chemical effective in the treatment and prevention of a disease caused by a filtrable virus. Another derivative was found to be more effective than sulfanilamide in combating bacterial infection in animals.

This is not to be taken as the sole line of interesting development bearing on therapy; for a pectin derivative has proved efficient as an aid in healing wounds, and from the research laboratory of the medical chemistry industry there comes a fairly steady stream of improved and beneficial products.

Silica gel has been used as a dry sponge material in which radium can be stored for long periods without loss of effectiveness. Most radium is kept dissolved, and elaborate pumps take off the gaseous disintegration product, known as radon, which is sealed in small metal containers. A dry sponge for this material has long been sought.

Review.

The year 1938 saw a considerable extention of research facilities, with the dedication of new institutes and laboratories. Much has been accomplished in perfecting new equipment delicate enough to aid in the furtherance of some research projects; and industry stands ready to proceed on a scale adequate to make commercially available other new products, as soon as a clarification of business conditions justifies such risks.

With an increasing number of better trained men engaged in all phases of chemical industry, there is some justification for considering 'all that is past is prologue.'