NOTES AND CORRESPONDENCE: Some Remarks on Standard

NOTES AND CORRESPONDENCE: Some Remarks on Standard Methods of Soap Analysis. Wilson Low. Ind. Eng. Chem. , 1919, 11 (12), pp 1169–1171...
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T H E JOURNAL OF INDUSTRIAL A N D ENGINEERING CHEMISTRY

DR. WM. H. WALKER,Massachusetts Institute of Technology, Cambridge, Mass. Manufacturing Problems of Gas Warfare. January 17, 1920. DR. CHAS.I,. PARSONS, 1709 G St., N. W., Washington, D. C. Nitrogen Fixation and Its Relation to Warfare. January 24, 1920. DR. HENRY FAY,Massachusetts Institute of Technology, Cambridge, Mass. The Amorphous State in Metals. January 31, 1920. DR. CHAS. I,. R E E S ~ E. , I. du Pont de Nemours & Co., Wilmington, Del. Explosives. February 7, 1920. NAVAL ACADEMY,

ANNAPOLIS,

MD.

DR. HENRYFAY, Massachusetts Institute of Technology, Cambridge, Mass. Iron and Steel. November 15, 1919, to post-graduate student officers., DR. JOHN JOHNSTON, Yale University, New Haven, Conn. The Utilization of Research. December 13, 1919, to postgraduate student officers. DR. ARTHURD. LITTLE, Charles River Road, Cambridge, Mass. Natural Resources in Their Relation to Military Supplies. January 17, 1920, to post-graduate student officers. DR. WM. H. NICHOLS,2 5 Broad St., New York City. Sdfuric Acid, the Pig Iron of Chemistry. February 6, 1920, to midshipmen. DR. WILLISR. WHITNEY,General Electric Co., Schenectady, N. Y . Industrial Research. February 7, 1920, to post-graduate student officers. DR. W. LEE LEWIS,Northwestern University, Evanston, Ill. Organic Research in Toxic Gases. .March 6 , 1920, to postgraduate student officers. DR. CHAS. I,. REESE, E. I. du Pont de Nemours & Co. Wilmirigton, Del. Explosives. April 2, 1920, to midshipmen, April 3 , 1920, to post-graduate student officers. DR. WILDERD. BANCROFT, Cornell University, Ithaca, N. Y. Organized Research. April 30, 1920, to midshipmen, May I , 1920, to post-graduate student officers. DR. WM. H. WALKER,Massachusetts Institute of Technology, Cambridge, Mass. Manufacturing Problems of Gas Warfare. May 15, 1920.

AM ERICAN INSTITUTE OF CHEMICAL ENGINEERS The twelfth annual meeting of this organization will be held in Savannah, Ga., December 3 to 6 , 1919, with headquarters a t the Hotel DeSoto. A series of papers and addresses devoted particularly to such southern industries as the naval stores, cotton, and turpentine and rosin industries has been included in the program, and excursions to the various chemical industries of Savannah and vicinity have been planned. The following schedule has been arranged : DECEMBER 3, 1919 9.15 Ax.-Meeting at Hotel DeSoto 12.30 P.M.-AUtO trip 8.00 P.M.-President’s address, A. D. Little DECEMBER 4, 1919 9.00 A.M.-Steamer trip, including visit t o ship building yards, and paper pulp mill 8.30 P.M.-Symphony concert DECEMBER 5, 1919 9.15 A.M.-Business session and reading of papers 2.00 P.M.-Auto trip t o Southern Cotton Oil Company’s plant and Fertilizer Plant of American Agricultural Chemical Company 7.00 P.M.-Dinner at Hotel DeSoto DECEMBER 6, 1919 Special trips to various industries

SOCIETA DI CHIMICA INDUSTRIALE The Societa di chimica industriale has been organized a t Milan for the purpose of promoting the interests of applied chemistry and chemical industry in Italy. Officers have been elected as follows: President: Dr. Alb Pirelli, of Pirelli & Co. Vice Presidents: Prof. Aug. Menozzi and Dr. Giov. Morselli, of the SocietA Elettrochimica del Caffaro. The first issue of the Giornale d i chimica industriale, which is published under the auspices of the new society, appeared in August 1919. The subscription price is 40 lire, and the address of publication via San Paolo IO, Milan.

NOTES AND CORRESPONDENCE SOME REMARKS ON STANDARD METHODS OF SOAP ANALYSIS Editor of the Journal of Industrial and Engineering Chemistry: In the August number of the Jourlzal of Industrial and Engineering Chemistry I noticed the title “Tentative Standard Methods for the Sampling and Analysis of Commercial Soaps and Soap of well known and Products,” by a Committee of the SOCIETY, capable men. The subject interested me, for I have been connected with the manufacture and analysis of soaps, glycerin, and allied products for the. past thirty-two years, and am still actively engaged along the same lines. I do not see how it is possible to have any “Standard Method for Soap Analysis,” except along the lines of a scheme of qualitative analysis which would start out somewhat in this fashion: The soap is liquid. Pass on to page 57. The soap is a solid. See page 60. Turning to page 60 we might find: It is a pure sodium soap. Pass on to page 71. It contains sodium carbonate, but no other foreign matters. Pass on to page 73. It contains alkaline silicates as well as sodium carbonate. Pass to page 74. It contains sodium hydroxide, as well as carbonate, silicate, etc. Pass to page 75. Etc., etc. It is only by such a scheme, which would include all branches of inorganic and organic analytical chemistry, that it would be possible to give orderly directions for the analysis of many soaps. All schemes, without exception, that I have seen for the analysis of soaps appear to have been reasoned or thought out and put

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down on paper without actual trial to see whether they worked as expected. For instance, for moisture, one is generally directed to weigh out a certain amount of the soap and then, either directly or after dissolving in alcohol, to evaporate to approximate dryness and finish drying to constant weight in an air oven at rooo C. to IO^' C., or some other limit. Such a method ignores several things, some of them serious, if accuracy is desired. I-Volatile matters other than water will be wholly or partially lost. 2-Caustic alkalies will be changed, probably‘entirely, to carbonates. 3-Oxidation products of the soaps themselves and organic matters in the soaps will surely be formed. 4-Sodium carbonate will not lose all its moisture a t such temperatures. 5-Sodium silicate will not lose its moisture short of a temperature that would burn up all organic matters present. And still this method is given time after time. We can show by actual tests that the above things happen, and often seriously affect the moisture determination Again for the determination of Free Caustic Alkali you are generally directed to dissolve the soap in strong alcohol, protecting from the air (often omitted) as much as possible, filter through some efficient filtering material, and From hereon it i s assumed that: Matters such as sodium carbonate, silicate, starch, clay, etc., are insoluble in the liquid present and remain upon the filter, while The soap and caustic alkali are t o be found in the filtrate. Salt is sometimes looked for in the residue on the filter, but if

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sufficient wash alcohol has been used it will be entirely in the filtrate. Now as a matter of fact, some of the sodium carbonate will be in the filtrate, for we make use of aqueous alcohol and the moisture in the soap also helps to d k t e it further, and sodium carbonate dissolves to some extent, as can easily be found out by concentrating the filtrate (keeping it strong in alcohol) when a precipitate will form, which will be found to be sodium carbonate. Sodium silicate is pretty insoluble in the liquids; small amounts will usually be found in the filtrate, apparently due either to colloidal solution or to mechanical entrainment in the filtration process. But the most serious thing is that sometimes little or none of the free caustic alkali will be found in the filtrate. Ignoring the fact that it may have been carbonated, and so tend to remain upon the filter, there is a more serious reason in the presence of silicate. The silicate used in soap manufacture is a highly acid silicate and is capable of forming four or five definite silicates of sodium, and this is one reason for adding it t o soaps, that it unites with any excess of free caustic aklali and binds it loosely. Some of these silicates of sodium are beautifully crystalline and can be easily formed and separated from the solution by the proper mixture of sodium hydroxide solution and silicate solution. One at least of these compounds can be filtered off or taken out by centrifugal action, and then forms a pure white crystalline powder, almost permanent in the air. This can be handled with bare hands without injury, and yet when dissolved in water undergoes hydrolysis, leaving the effect of free caustic alkali. Now when a soap containing silicate and caustic alkali is treated with strong alcohol, a combination of the free caustic and silicate takes place, if it has not previously done so, and forms a compound that is not entirely decomposed by neutral alcohol, a t the boiling temperature, and so such a compound remains upon the filter, and ’f sufficient silicate is present, practically all the caustic remains combined with it, on the filter. This point is always overlooked. But we have formed this compound and we have determined the practical composition of the compound of silicate and caustic that remains upon the filter. Again starch and caustic alkalies form combinations, and such combinations are used commercially as detergents, such as cornmeal ground up with strong caustic soda solution, which is dried and made into a soap powder. Such compounds show 1zo free

caustic. I n the determination of total fatty acids usually no reference is made to the fact that even on heating with water some fatty acids will be converted partially into anhydrides. That the neutralizing value and saponifying value of fatty acid, is rarely exactly the same, is due principally to this cause. Precautions are not usually taken to prevent oxidation and volatilization of the fatty acids while drying. Fatty acids (those usually met with in soaps) easily lose weight in a current of air when heated to I O O O C.; they also are subject to oxidation. Petroleum ether is recommended as a solvent by many who seem to prefer this substance to ether on account of its supposed cheapness. When properly purified it is not as cheap as it seems a t first. Petroleum ether is a poor solvent for oxidized or hydroxylated fatty matters, and is favored, commercially, in many cases for this reason. It is a very useful solvent for many purposes, but it should be used intelligently and not assumed to be the equal of ether for total fatty matters. Further than this, petroleum ether not only is apt to leave a residue very hard to volatilize when being evaporated from a substance like fatty acids or soaps, but, more serious, it often, for some unknown reason, acts as a catalyzer in causing rapid oxidation of the fatty acids or soaps during evaporation in air. Direct experiment shows this. The determination of unsaponifiable matters was long a very

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bothersome operation, but a t the present time we have very excellent commercial methods. There are two published methods that give good results, and one unpublished method (our own) that we believe gives better results. Twitchell’s1 method makes use of either to extract a diluted alcoholic solution of the soap. It results in always leaving more or less free fatty acids, of unknown combining weight, in the final weighed residue. He titrates and assumes oleic acid to be present, and deducts the amount found from the weighed residue. In many cases this works nicely, in others i t results in great errors. We used the process for a long time, and often found the free fatty acids left were largely in excess of the actual unsaponifiable matters. The method of the Committee on the Tentative Standard Methods for the Sampling and Analysis of Commercial Fats and Oils2 employed petroleum ether for the extraction of a soap solution containing considerable alcohol. It is a better method than Twitchell’s and evidently the authors of the method thought that no free fatty acids were left with the final residue, for no provision or advice is given for correcting for them. However, in our hands, on various substances, free fatty acids are always left in the final residue, but not nearly as much as with Twitchell’s process. We modify the committee’s method slightly, with the results that our residues, while containing all the unsaponifiable matter possible by this method, contain either none or the smallest amounts of free fatty acids. While very concordant results are easily obtained nowadays for unsaponifiable matters, there is still a question whether we get them all, and also a serious question, in trying to purify them by re-solution and recovery after another saponification, whether we destroy or change some of these matters, or whether we really had impurities in the first place. Such residues are very apt to lose seriously in weight on resaponification and recovery and this may continue through several repetitions before anything like constancy is attained. The final substances in such cases appear purer substances, and we are inclined to think some true unsaponifiable substances are changed by boiling with alcoholic alkali, and so lost to subsequent extraction. Twitchell’s method for rosin was a blessing when it appeared. It has been well tested out and used for years and gives fair results, very good results when one knows what he is dealing with, But it does not recover by weight all the ingredients of the rosin originally present. We found years ago that we got better results by paying no attention to the rosin matters, but recovering the fatty acids. If the mixture of fatty acids and rosin or rosin acids is weighed, to start with, one gets the fatty ethers a t one stage. If these are recovered, saponified, and the fatty acids recovered and weighed, there is all the data necessary for knowing how much rosin was present originally, and it does not make any difference how much of the resinous products was lost during the process. As one starts with fatty and rosin acids and ends up with the same fatty acids, less the rosin acids, the amount lost must have been the rosin acids, etc. I n the analysis of soaps, as with alloys, the determination of one ingredient is so dependent upon the presence of other ingredients that i t is impossible to give a standard method. The chemist has to use all his knowledge and ability, both mentally and mechanically, to arrive approximately a t the truth. It is possible, and desirable, to have standard methods to apply to any one kind of soap, where all the ingredients are known. This is the best covered by specifications where directions to operate in a certain manner are given and it makes no difference whether the result is a true one (for a certain ingredient) or not; the specification states the limits within which the result must come to be acceptable. The difficulties of a soap analysis may be better appreciated 1

THISJOURNAL, 7 (1915), 217. 11 ( 1 9 1 9 ) , 69.

* I b i d . , 10 (1918), 315;

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if it is considered that an ordinary bar of laundry soap generally will contain: Fatty anhydrides Rosin anhydrides Sodium oxide, combined as soap with the above Unsaponifiable matters, from both the fatty and rosin matters, mineral oil, etc. Perfume, or essential oils Sodium carbonate, as filler and hardener Sodium hydroxide, free or free and combined with silicate Sodium silicate, free or hardener, and neutralizer of caustic Sodium chloride Sodium sulfate Unsaponified matter, particularly in cold soaps, rarely in laundry soaps Lime, magnesia, aluminum, iron, or other metallic salts in small amounts Water Glycvrin, always present t o some extent Naphtha, borax, ammonium chloride, etc., always possibilities

This does not begin to exhaust the list, but covers those things usually present, and in getting up a scheme of analysis the efTect of these things on one another and towards the reagents must always be borne in mind. We have methods to determine with considerable accuracy any of the above ingredients, but we would hesitate to try to get up a standard method by which they could all be found in turn. I t takes special methods and special apparatus for many of them. WILSONH. Low THECUDAHY PACKING COMPANY OMAHA,NEBRASKA September 5, 1919

T W O LETTERS ON THE TREATMENT OF LOW-GRADE NICKEL ORES Editor of the Journal of Industrial and Engineering Chemistry: It was with much pleasure and interest that I read the article by Mr. C. W. Davis [THISJOURNAL, 11 ( ~ g ~ g6441 ) , relative to thc. treatment of low-grade oxide nickel ore. While appreciating his courtesy in mentioning my name in his acknowledgment in connection with a reduction test on nickel ore of North Carolina, I wish to emphasize that the reduction was done on my own request and initiative, Mr. Davis being kind enough t o supply me the ore sample. Moreover, the idea of rendering the refractory nickel ore soluble by meam of a reducing roast with gas, without fusing the ore, preventing reoxidation by cooling, originated with me. The results of this reduction test confirmed my theory. No doubt Mr. (2. W. Davis, a friend of mine, must have not purposely forgotten this point in his acknowledgment, and it is therefore with friendly feelings that I bring this matter to his attention. 5 WILHELMINA LAAN M. H. CARON WELTBVREDEN, J A V A ( N . August 31, 1919

E. I.)

............ Editor of the Journal of Industrial and Engineering Chemistry: Referring t o the above criticism of the paper which was published in the July issue of your journal, Mr. M. H. Caron is correct in stating that the idea as well as the actual reduction of the nickel ore was his. I regret exceedingly that this point was not covered in my acknowledgment in that paper, for I had no thought of claiming t o be the originator of a method of ore ti eatment which has been patented by Mr. Caron. CHARLESW. DAVIS BUREAUOF MINES EXPERIMENT STATION GOLDEN,COLORADO November 3, 1919

A SELECTIVE BIBLIOGRAPHY ON WASTE UTILIZATION AS AFFECTED BY THE WAR By E. D. GREENMAN, Librarian, Arthur D. Little, Inc., Cambridge, Mass. “Alcohol from Garbage,” Munzcipal Engzneerzng, 79 (1917). 731-732. Alpera, K. “Utilization of Plum Stones for Oil in Germany.’’ Pharmazeutischc Zeitung, 63 (1918), 534.

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Anderson, J. “Junk is America’s Richest War Brige.” Scientij5c American Supfilement, 84 (1917), 328-329. Austrian War Association of the Oil and Fat Industries. “Fat Recovery from Waste Waters.” Seifenfabrikant, 38 (1918), 596-7, Municipal’ Bamman, F. C. “Army’s Utilization of Camp Wastes.“ Journal, 46 (1919), 304-8, 322-5. Bamman, F. C. “War’s Influence on the Garbage Pail.” EngineeringNews Record, 82 (1919), 373-8. Barbour, P. E. “Waste of Less Common Materials in War.” Journal’ of the American Society of Mechanical Engineers, 38 (1916), 447-448. “Battlefield Salvage of War Metals.” Engineering and Mining Journal, 105 (1918), 380. Brown, T. P. “Food Wastes-Some Causes and Remedies.“ Journal ofthe Franklin Institute, 185 (1918). 585-610. Brownsdon, H. W. “Use of Cartridge Scrap.” Engineering and Mining Journal, 104 (1917), 874. Doten, L. S. “Sewage and Waste Disposal for the U. S. Army.” Proc. Amer. SOC.Civil Engineers, 45, 233-48. Ellison, J. A. “Camp Wastes Yield Large Revenue to the Government.” Engineering News Record, 79 (1917), 731-732. Fahrion, W. “Sources of F a t in Germany in 1916.” Zeitschrift f a r angewandte Chemie, SO (1917), 125-126. “Five War-time Ways to Prevent Waste.” System, 3 1 (1917), 524-525. “Food Administration’s Garbage Utilization Campaign.” Municigal Journal, 46 (1918) 135-136. Hammond, Edward K. “Salvaging Tools in War Time.” Machinery, 24 (1918), 771-779. Hankin, J. “Restoration of Materials after Fires.” Scientij5c American S u p p l e h a t , 85 (1918), 111-112. Harrington, J. W. “The Saving Grace of War.” Scientific American, 119’ (1918), 454. Hatch, L. “The Food Administration and the Nation’s Response.” Scientific American, 119 (1918), 390. Hering, R. “Effect of War Conditions upon Production and Disposal Municipal and County Engineering, 45 (1918), of Municipal Refuse.” 146. Hoover, C. P,, and Banks, T. D. “Production of Alcohol from Garbage, Columbus, Ohio.” Engineering and Contvacting, 47 (1917), 545. Ingram, A. E. “British Utilization of Waste Materials.” U. S. Bureau of Foreign and Domestic Commerce. Daily Consular and Trade Reports, 86 (1917), 161-162. “Junk Men of the War; What Becomes of the Wreckage of the Battlefield.” Scienii.fic American Supplement, 86 (1918), 264-265. “Kitchen Waste Being Used in Making Explosives.” N . Y . Journal of Commerce, August 31, 1917. Klimot, J. “Wartime Vegetable Oils.” Post-51 (1918), 561-2 Pharmaceutische. Kling, M. “New Feedingstuffs Used in Germany during the War.” Landwirtsch. Jahrb. fer Bayern, 6 (1916), 483-513; also in Bulletin Agricultural Intelligence, 8 (1917), 892-9. Knowlton, W. T. “Waste Products of Cities and the War.” Municipal Journal, 46 (19181, 510-513. Koch, F. J. “Harvest of the Battlefields; How the Boundless Fortunes in Old Metal of Every Sort will be Garnered from the War Zone once Peace is Declared.” Metal Industry, 16 (1918), %LO. Lamb, M. C. “Utilization of Condemned Army Boots.’’ Scientific American Supplement,, 85 (1918), 122. “Making Soaps and Munitions from the Garbage Pail. Scientific American, 119 (1918), 200. “Making the War Help Win the War.” Engineering News Record, 8 1 (1918), 387. Manlove, George H. “Junk Pile Transformed into Gold.” Iron Trade Reniev, 62 (1918) 1173-1176. “Meeting Higher Costs by Wasting Less.” System, 3 1 (1917), 99-101. “Metal Salvaged from the Scrap Pile in 1916.” Foundry, 46 (1918), 79-80. Nasmith, F. “Utilization of Cotton Waste by German and Austrian Methods.” Textile World Journal, 49, Sup. 251, May 1915. Osborn, I. S. “Effect of the War on the Production of Garbage a n d Methods of Disposal.” Engineering and Contracting,48 (1917), 483-484. “Power from Refuse.” Journal of Industrial and Engineering Chemistry, 10 (1918). 74. “Reclaim All Industrial Waste as a Patriotic Duty.” Industrial Management, 53 (1917), 785-788. “Recovery of Offal and Wastes of the Army Co.mmissary Centers.” Journ. Pharm. Chim., 14 (1916), 328-329. (Description of the recovery of lard, soap, ox-foot oil, sausage casings, dried blood, bones, etc.) “Salvage .of Waste Material in England.” American Society of Mechanical Engineeus, 40 (1918), 713-714. “Salvaging of High-speed Steel.” Iron Trade Review, 62 (1918), 845-848. “Saving Fats from Garbage; American Chemical Society Offers t o Aid Food Administration.” Journal of Industrial and Engineering Chemistry, 10 (1918), 320. “Saving Waste Lumber a t Army Cantonments.” Scientijk American, 118 (1918), 59. “Sawdust as a Famine-foodin Germany,” Literary Digest, 50 (1915), 1398.