Nov., 1919
T H E JOURNAL OF INDUSTRIAL A N D ENGINEERING CHEMISTRY
gum veneer, such as is ordinarily used in packing boxes, while 5 0 lbs. per sq. in. is sufficient t o pull t h e fiber from any of t h e kinds of paper usually used for making built-up board for shipping containers and wall-board. T h e tensile strength of silicate of soda mixtures used for acid-proof cements is easily brought u p t o 1700 lbs. per sq. in. for air-dried briquettes, while t h e bond produced by baking silicate of soda and clay, as is t h e practice in t h e manufacture of abrasive wheels, easily yields a strength above 2,000 lbs. per sq. in. T o recount all t h e uses of silicate of soda and t h e properties on which they are based is beyond t h e scope of this article, b u t in spite of its diverse applications in t h e arts a t this tine i t is plain t o those who have worked with it t h a t much remains t o be learned. Studies are in progress which it is hoped may be useful.
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CHEMICAL DEPARTMENT PHILAI>ELPHIA QUARTZ COMPANY PHILADELPHIA, P A .
PHTHALIC ANHYDRIDE.
I-INTRODUCTION
By H. D. GIBBS Received August 19, 1919
Early in t h e year 1916 my attention was directed to t h e shortage of phthalic anhydride and its derivativesl and t h e difficulty attending t h e manufacture of this valuable intermediate for certain dyes and medicinals b y t h e known processes. The best known and most economical process consisted in the oxidation of naphthalene by means of sulfuric acid in the presence of mercury compounds as catalyst.2 An extensive study of this process on a laboratory scale was very disheartening and my experience in this regard was borne out by t h a t of many other investigators. The yields were very erratic for unknown reasons, occasionally reaching 55 per cent of t h e theoretical, b u t averaging nearer 2 5 per cent. This line of investigation was discarded very early and experiments on the vapor phase oxidation of naphthalene in t h e presence of catalysts were begun with a view t o paralleling a similar process for t h e production of benzaldehyde b y t h e air oxidation of toluene. The shortage of t h e supply of benzaldehyde for commercial uses had resulted in requests upon t h e Bureau of Chemistry for information concerning t h e best methods of manufacture and led t o studies on t h e chlorination of t o l ~ e n esince ,~ this process is generally regarded as t h e first step in t h e large-scale pro1 At this time very little phthalic anhydride or phthalic acid rras made in this country and the little that was made was produced a t great expense by t h e use of sulfurlc acid as an oxidizing agent for naphthalene. Consequently there arose a shortage of phthallc anhydride derivatives and the prices were very high. The abnormal prices were about as follo-s Phthalic anhydride, $7.50, and small lots a t $14 per lb , phenolphthalein, $8 t o $20; rhodamine Bx, $75; eosine, $12 t o $15; erythrosine, $24, and purified for food color 530, rose bengale, $50. In 1917 (the Tariff Commission, Census of Dyes and Coal-Tar Chemicals 1917) small quantities of rhodamine B, uranine, phloxine P, and rose bengale B weie manufactured and average prices for the following are reported: Phthalic anhydride, $4.23 per lb.; phenolphthalein, $9 65, eosine, $8.58, and erythrosine, $11.31. Levinstein, J . Soc. DYeYs Colouists, [61 17 (1901), 138, “Uber Indlgodarstellung,” Chem.-Ztg., 32 (1908), 602. 8 Gibbs and Geiger, U. S. Pat. 1,246,739 (1917).
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duction of benzaldehyde and some other valuable compounds. This laboratory was engaged in studies on malachite green and was therefore interested in t h e production of benzaldehyde. Very shortly afterwards I was impressed b y the advantage of a direct oxidation process, if such could be devised, eliminating several troublesome steps in t h e introduction of t h e oxygen in t h e side chain of toluene. Many methods have been proposed for oxidizing t h e methyl group of toluene in t h e wet way with solutions of various oxidizing substances, b u t these were not studied, being discarded in favor of vapor phase studies. Mixtures of oxygen and toluene, and later atmospheric air and toluene, were passed into contact with various substances a t temperatures varying from t h e boiling point of toluene t o 5 5 0 ~ . Every substance tested by this method, and they were very numerous, catalyzed t h e reaction more or less, t h e valuable products being benzaldehyde and benzoic Ultraviolet light was acid, t h e former predominating. without effect. The oxides of the metals1 of t h e fifth and sixth groups of t h e periodic system were found t o be most efficient, vanadium first and molybdenum second. I first gave a summary of this work at t h e Fifty-third Meeting of t h e AMERICAN CHEMICAL SOCIETYin New York, before t h e Division of Industrial Chemists and Chemical Engineers, September z 7 , 1916. A further account of t h e work was read a t t h e Kansas City Meeting in April 1917. Studies of t h e remarkable properties of t h e compounds of molybdenum and vanadium, both in a pure state and mixed with various other ingredients, in their power t o catalyze other oxidation reactions were prosecuted and t h e next success was in producing phthalic anhydride from naphthalene. The principal reactions t h a t have been developed are: naphthalene t o phthalic anhydride,2 anthracene t o a n t h r a q ~ i n o n e ,phenanthrene ~ t o phenanthraquinone.4 Others are under investigation. Methods for purification of phthalic anhydride have also been studied.6 The demand for phthalic anhydride being most acute, t h e naphthalene oxidation was t h e first t h a t was carefully investigated, t o determine t h e best conditions of temperature, gas mixture, time of contact, and condition of catalyst t o produce t h e optimum yield. The best laboratory experiments gave a conversion equivalent t o 8 2 per cent of t h e theoretical yield or about 95 g. of phthalic anhydride for each I O O g. of naphthalene. A small-scale factory unit was constructed in t h e laboratory and operated for one hour with t h e production of about 1 5 0 g. of phthalic anhydride. The operation was then discontinued because of evident defects in t h e construction. T h e Department of Agriculture issued an announcement6 on June 16, ~ 9 1 7 ,offering cooperation with 1
Gibbs, U. S. Pat. 1,284,887 (1918); application filed September 22,
1916. Gibbs and Conover, U. S. Pat. 1,284,888 (1918) and 1,285,117 (1918). U.S. Pat. 1,303,168 (1919). Lewis and Gibbs, U. S. Pat. 1,288,431 (1918). Conover and Gibbs, U. S. Pat. 1,301,388 (1919). THISJOURNAL, 9 (19171, 815; 022,Paint and Dyug Reporlev, June 25, 1917, p. 16. 2
a Conover and Gibbs,
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chemical manufacturers for the purpose of introducing t h e process into t h e plants on a commercial scale. Some months later all of the cooperation t h a t could be handled advantageously was effected and the constantly increasing pressure of war problems employing t h e laboratories and personnel made it advisable t o withdraw t h e offer, which was done on Iiovember I, 1 9 1 7 . ~ Shortly after the signing of the armistice it was decided t o reopen the offer of cooperation and a n announcement t o t h a t effect was issued on March 17, 1 9 1 9 . ~The reasons for this action were several. First-The work upon war problems was prdctically over and men and funds were again arailable for t h e work for which this laboratory was planned. Second-Several manufacturers stated t h a t they could not enter into the cooperative agreement when first announced because a t t h a t time their entire staff was devoted t o work on hand, but t h a t now their resources were larger, war work was over, parts of the plant were idle, and they would like t o be put in position t o utilize t h e information originally given t o other cooperators and upon the same terms. Third-Publications of the completed work will not be ready for an indefinite period, since t h e scope of t h e investigations is undergoing great expansion, and it is considered desirable t h a t the manufacturing process first be firmly established in this country. I n t h e interim cooperators are furnished immediate reports on t h e latest developments. Fourth-It seems desirable t h a t a number of plants work upon t h e same problem in order t h a t t h e best commercial installation be ultimately obtained. Although t h e development was delayed somewhat b y war conditions, t h e large-scale manufacture of phthalic anhydride is now proceeding in a satisfactory manner, and it is believed t h a t eventually t h e details of the factory units will be so worked out t h a t this process will be t h e most economical and practicable known for making phthalic anhydride. I n fact, phthalic anhydride may become one of the cheapest organic compounds. It is interesting t o note t h a t the phthalic anhydride produced b y this process is of a remarkable degree of purity. Naturally it is free from chlorine or sulfur compounds, common impurities in phthalic anhydride as formerly found on t h e market. Many d a t a on t h e work have accumulated and new facts are continually being discovered. A series of papers descriptive of t h e work is now in preparation and will appear a t intervals when t h e status of this and other investigations will permit. COLOR LABORATORY
U.S. BUREAUOF CHEMISTRY
Vol.
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t h a t of whether black powder in which a small part of t h e potassium nitrate had been replaced by potassium perchlorate was less resistant t o moisture t h a n straight black powder. This led t o a brief study of t h e conditions under which black powder absorbed atmospheric moisture, t h e results of which are presented in this report. The fact t h a t powder is more effective in the moisture-free condition is embodied in t h e old admonition t o ‘‘keep.your powder dry.” The methods followed were those of a previous investigation on moisture absorption by detonators.1 The rate of moisture absorption in a saturated atmosphere was determined a t 2 j 0 C. by exposing the material in shallow flat-bottom crucibles. Ordinary ’ quart jars closing with glass tops and spring clamps were filled about an inch deep with distilled water; in each jar was placed a copper wire tripod for supporting one crucible. The jars were then closed and submerged completely in a large water thermostat electrically heated and stirre’d, and controlled b y a toluene thermoregulator within * O . O I O of 2 j 0 C. Two grams of the material whose rate of moisture absorption was t o be determined were spread evenly over t h e bottom of t h e crucible (3. 7 cm. in diameter), t h e crucible brought t o 2j0, and placed in one of t h e jars. After a certain number of hours t h e crucible was removed, placed in a weighing bottle, and weighed. Each result was obtained from a separate crucible, as it was found unsatisfactory. t o return t h e same crucible t o t h e jar, on account of change in temperature of t h e crucible during weighing and slight losses in moisture while handling. I t was found in t h e previous investigation* t h a t t h e moisture absorbed in a given time b y pure salts under t h e conditions above outlined was independent of t h e weight of salt taken within certain limits (0.j t o 2 . 0 g.) and also independent of t h e degree of fineness t o which the salt was ground. The relative rates of moisture absorption of different salts were found t o be proportional t o t h e difference between t h e vapor pressures of their saturated solutions and t h e partial pressure of water vapor in t h e surrounding atmosphere. It follows t h a t when this difference is zero or when t h e partial pressure of water vapor in the surrounding atmosphere is less t h a n t h e vapor pressure of t h e saturated solution of the salt no moisture will be absorbed. I n the latter case a moist salt would dry out. I n American practice black powder is a mixture of 7 5 per cent potassium or sodium nitrate, I O per cent sulfur, and I j per cent charcoal. Moisture absorption is largely due t o t h e nitrate or soluble constituents. Charcoal plays a small part.
WASHINGTON, D. C. E X P E RI & E NT !I A L
HYGROSCOPIC PROPERTIES OF BLACK POWDERa By G. B . TAYLOR Received May 21, 1919
Among t h e questions referred t o t h e Bureau of Mines b y t h e military authorities during t h e war was 1 2
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THIS JOURNAL, 9 (1917), 1148. Ibid., 11 (1919), 489. Published by permission of Director, U. S. Bureau of Mines.
Two samples of black powder were submitted by t h e Ordnance Department for test. These were given t h e laboratory numbers M - 2 3 3 2 and M - 2 3 3 3 . The size of grain appeared t o be F. For comparison, t h e 1 G . B. Taylor and W. C. Cope, “Hygroscopic Properties of Sodium, Potassium, and Ammonium Nitrates, Potassium Chlorate, and Mercury Fulminate,” Met. & Chem. Eng., 16 (1916), 140. 2 L O C . cit.
