influence of New Solvents on Development of Chemical Industries C. L. G A B R I E L /
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N GENERAL the term "solvent" will be construed to mean a liquid product which will dissolve gases, liquids, or solids without the occurrence of any chemical reaction. For the purpose of this discussion new solvents will be considered to be products developed since 1920, and old solvents which have been produced by new processes since that year will be included. In many instances these new materials are also raw materials for chemical syn-
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theses, so that thought should be given t o some of their more important derivatives.
Commercial Solvents Corp., N e w York, N . Y .
duce n-butyl alcohol as the major product and acetone as the secondary material. Butyl alcohol or butanol is unquestionably the first new solvent appreciably to influence the normal growth of the chemiProduction of Butyl Alcohol and cal industry, and after 20 years deAcetone velopments are still being made which The year 1920 is not arbitrarily chosen may be blamed on or credited to it. For a to distinguish between old and new solconsiderable period prior to 1920 there vents. In that year the Weizmahn ferhad been no outstanding developments mentatiqn process first was used to proin solvents. The chief members of this group in use when that year began were the coal-tar solvents, petroleum naphthas, acetone, methanol, ethyl alcohol, carbon I tetrachloride, ether, chloroform, and a limited amount of fusel oil and its derivative, amyl acetate. •-'" J The Weizmann fermentation process was first operated in Kngland during the World War. Corn was used as the raw material, and by means of a special bacillus the carbohydrate content of the corn mash was converted into acetone and butanol. The process was used for the pro-.-". | ,'{L,. j --ZLv—f~•" 3 3JfUr= duction of acetone, as this solvent was badly needed for high explosives and airplane dopes. At that time the only other acetone available was made from calcium \ if]} acetate, which in turn was a product of 1 the destructive distillation of wood. The ".j-i" production of acetone was far below war needs. Therefore in spite of the yield of - *u \ 2 pounds of butanol for each pound of / , *" - acetone by the Weizmann fermentation, - -."_ -•- V'
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The two industrial pictures which are published here show some of the equipment in the nitroparaffin derivatives building of Commercial Solvents Corp.
1 Presented at a meeting of the New York Section, Inc., of the American Chemical Society, Hotel Pennsylvania, New York, N. Y., December 6, 1940.
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132 this relatively inefficient acetone process was put into large-scale use. As about 10 pounds of solvents were produced per bushel of 56 pounds of corn and as only about 3 pounds of these were acetone, almost 20 pounds of corn had to be transported to England to obtain 1 pound of acetone. Because of the great need for ocean shipping space and foodstuffs, operation of the process was transferred to Toronto, Canada. An old distillery was later acquired at Terre Haute, Ind., and when the United States entered the war a second distillery was purchased in that city. Both were operated by a company jointly owned by the British and American Governments. With the cessation of hostilities the Terre Haute plants were shut down. No one could afford to operate the fermentation process solely for the production of acetone, in view of the competition of the wood distillation product and a normal market of only about 4 million pounds per year in this country. However, about the time the World War ended it was found that butanol and its derivative, butyl acetate, could be used to replace fusel oil and its ester, amyl acetate, as solvents for nitrocellulose. Based on the belief that the nitrocellulose lacquer industry could be expanded substantially if solvents were available in practically unlimited quantities, the production of butanol was undertaken at Terre Haute in 1920, and the acetone simultaneously obtained was for the first time considered to be the less important material. Fusel oil, from which amyl acetate is made, was obtained solely as a by-product of ethyl alcohol distillation and the amount of fusel oil produced was therefore definitely limited; the total available in all countries probably did not exceed 5 million pounds per annum. At that time nitrocellulose lacquers were chiefly used for finishing small metal articles. Practically none of the paint and varnish manufacturers produced lacquer. When they wanted clear lacquer to sell with aluminum or bronze powder for the gilding of steam radiators, picture frames, and other similar small items, it was purchased from one of the dozen lacquer producers. However, * this situation changed when in 1924 the availability of butanol and butyl acetate made possible the initial large-scale utilization of nitrocellulose lacquers for finishing automobiles. The first successful application clearly indicated to the paint and varnish industry that lacquer was a finishing material which should be added to its line if sales of its finishing materials to the automobile industry were to be continued. While the production of automobiles is not a part of the chemical industry, nevertheless the advent of lacquer had a great influence on the mass production of these mechanical -contrivances. It cut down the finishing "operations from weeks to hours, so that the production line could be kept in motion right through the finishing room, and resulted in sub-
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stantial savings in labor and space. Imagine the acres of floors which would be required to finish automobiles if production were over 100,000 per week and half a month were needed to paint a car properly. It was not long before nitrocellulose lacquer finishes were used in other industries such as the manufacture of refrigerators and furniture. Synthetic Solvents This huge and rapid growth in the consumption of lacquer and butanol and butyl acetate, the chief solvents used in it, had several important influences on chemical development. In the first place there began to appear competing solvents such as the ethers of ethylene glycol and their acetates, and amyl alcohol produced from pentane and its acetate. The production of synthetic butanol was also started in this country. Plants were installed to produce isobutyl alcohol by high-pressure synthesis from carbon monoxide and hydrogen, and secondary butyl and amyl alcohols from butylene and amylene, respectively. A new butanol fermentation, using blackstrap molasses in place of corn, was developed. The ethers of ethylene glycol are made synthetically with ethylene as the raw material. This is converted into the chlorohydrin which, when treated with a base and subsequently distilled, forms ethylene oxide. The reaction between ethylene oxide and ethyl alcohol produces the monoethyl ether of ethylene glycol. The acetate of this is made by the usual esterification process. Amyl alcohol is produced by first chlorinating pentane and then treating it with caustic soda. Isobutyl alcohol is made in the same type of plant which is used for the synthetic production of anhydrous ammonia or methanol. The synthesis is operated at pressures between 300 and 900 atmospheres. The raw materials required are carbon monoxide and hydrogen, which are obtained from either coal or hydrocarbon gases. Different alcohols from methanol up are made by varying the catalyst, the ratio of carbon monoxide to hydrogen, the speed at which these gases pass over the catalyst, and the temperature. Secondary butyl and amyl alcohols are made from butylene and amylene, obtained from oil-cracking stills. They are first treated with sulfuric acid and the sulfates in turn are hydrolyzed with water to form the alcohols. Synthetic butanol uses as the raw material either acetylene or ethyl alcohol. In either case the first step is the preparation of acetaidehyde, after which each synthesis is identical, regardless of which raw material was used. Acetaidehyde is condensed to aldol. The aldol is converted in the presence of a dehydrating agent to crotonaldehyde, which on hydrogenation goes through butyraldehyde to butanol. The liquid portion of nitrocellulose
Vol. 19, No. 3 lacquers contains not only butanol, butyl acetate, and other solvents with similar evaporating rates which have previously been discussed, but diluents and lower boiling solvents. Formerly toluene was the chief diluent. However, in recent years the petroleum industry has developed special cracked petroleum fractions approximating toluene in evaporation rate and solvent power. These are now largely used in nitrocellulose lacquer, either with or without toluene. The chief lower boiling solvent used in nitrocellulose lacquers is ethyl acetate, but in this case, too, competitive materials derived from petroleum gases have been made. These are methyl ethyl ketone, which is produced by the oxidation or dehydrogenation of secondary butyl alcohol, and isopropyl acetate, an ester of isopropyl alcohol made from propylene gas. Besides solvents and diluen-fcs, nitrocellulose lacquers require resins and plasticizers. Early lacquers used natural dammar gum as the chief resin. The production of synthetic resins as a partial or complete replacement for dammar followed. The more important of these are ester gum and the Glyptals. The former is made from glycerol and rosin, and the latter from glycerol and phthalic ajnhydride. The Glyptals can be modified in many ways, including incorporation of various oils in the resin and inclusion of sucOh acids as maleic and sebacic, which also react with the glycerol. The important plasticizers used are dibutyl phthalate and tricresyl phosphate, both synthetic materials. A few figures on the United States production of some of the chemicals which enter into nitrocellulose lacquer, as given in the U. S. Tariff Commission Heport for 1939, best illustrate the growth of industries which may be attributed to the production of butanol. In 1939, 127 million pounds of butyl alcohols were produced, of whicii about 73 million pounds were normal butanol. A. considerable portion of the various butyl alcohols was converted into butyl acetates, as the Tariff Commission figures show a production of approximately 78 million pounds of these. The figure for ethyl acetate is 68 million pounds. Approximately 8 million pounds of dibutyl phthalate were made in 1939. It is misleading to give here the production figure for the alkyd type resins ax Glyptals, for a good part of the total is used in finishes other than nitrocellulose lacquers. However, approximately 76 million pounds of such resins were produced in 1939, of which 70 million pounds were made with phthalic anhydride and 6 million pounds with maleic anhydride. This is a rapid growth for ajn industry which turned out only 10 million pounds in 1933. Synthetic Finishes The rapidity with which lacquer could be applied brought forth an almost con-
February 10, 1941
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in two ways—as a solvent for dissolving Influence of Acetone e remembered that all known and available at that time were rigid materials. This, then, is the brief background of plastics in apparel. The turning point c a m e simultaneously with the introduction o f the many new plastics which have been placed on the market in the past 12 or 15 years. Four major types of plastics are u s e d : rigid thermosetting materials; rigid thermoplastics; flexible, elastic thermoplastics; and textile fibers made from plastics.
(16); and the same materials in a variety of attractive, transparent, colored shoe heels (IS). Rigid, Colored Thermoplastics The availability of really colorful materials, a feature of thermoplastics, has made them far more important to the apparel industry. Among the thermoplastics which have gained wide acceptance as apparel materials are the cellulose esters, methyl methacrylate, polystyrene, rubber hydrochloride, vinylidene chloride, and polyvinyl esters. Three cellulose esters, the nitrate, acetate, and acetobutyrate, and combinations of glass fibers and cellulose acetate have all been employed t o some extent. Cellulose nitrate collars are obsolete, but cellulose nitrate shoe-heel covers (4) have attracted considerable attention. This plastic suffers the disadvantage of its high flammability and its less flammable homolog, cellulose acetate, has therefore assumed a greater importance. Molded cellulose acetate is used in bracelets, brooches, necklaces, shirt studs, cuff links, hat brims (4), slide fasteners, and buttons (17). Its adaptability, moldabilit}r, and availability in color have all contributed to improvements in such items. Another interesting application is the appearance of glass fibers coated with cellulose acetate for the braided tops of women's shoes (7) and for bracelets. Cellulose acetobutyrate, which has greater toughness than the regular grade of acetate, is employed for football helmets.
Thermosetting Plastics The thermosetting materials appear in tfcie apparel field as casein, molded phenolformaldehyde, cast phenolics, and ureaformaldehyde. All are used in buttons of various types, although several have been applied i n articles which are part of women's ensembles. Representative of tfciese uses are molded phenol-formaldeh y d e in jewels for studding handbag fabrics, the so-called findings; cast phenolics io. handbag frames and costume jewelry MODERN PLASTICS A N N U A L C O M P E T I T I O N
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Presented at a meeting of the New York Sect i o n , Inc., of the American Chemical Society, N « w York, N . Y., December 6,1940.
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A flexible, resilient Vinylite plastic is used around insteps of these shoes.
