amfacture of Picric Acid' By Hang S. Reed h~XCl3IGANAOUCVLTWRAL COLLBOZ, EAST
' "'' 'he
''
enrly
Of
LANSING, MZCX.
ground about every rod in the line of the pots. Screw eyes were set in the tops of the posts and a 1-inch M a d s roDe led through the eyes dirccily over the center line of the pots for the entire length of the row. The crocks mere fitted with wooden cove:'s in i ~ h i c hmere two lioics. One ~ I C iil: the centcr admitted a 2 x 2-inch oak stick standing vertically, vc-ith s pin through it at such a height as to allow the lower end to sving just clear of the bottom of the crock. The upper end of the stic!c was fastened to the Manila rope. The otlicr hole tlirough the crocks vas about 6 inches in diameter and near the circuniforence of the crock. T!iis opcniiig \vas used for clinrging t l x crock. Thc operation of this plant consisted in sulfonating the phenol sonicwliere at one side in a lead-linccl moodcn tank, drawizg the plicnolsulioiiic acid into x large crock oii a l~nncl truck, then bringing the truck d o n g beside the ! ~ kdipping , the phcnolsulfonic acicl froin :lie crock on the truck with n
This article is nof an aflempf lo gioe
absolute specifications for a plant f o rnanufacfure picric acid, but simply to gioe some general ouflincs of procedure which came t o fhe wiler's nofice during his experience in manujacluring many lhousnnd pounds of picric acid and ammonium pimatc,
Governn'cnbs "lne to "lis countrk' to place orders for niunitions, ainong mhich TYW picric acid in w r y large quantit,ies. Cousicierable excitoment was aroused among many New York brokers who thought they snw a fortune coming their wcy ovcr 1:ight;and many contracts were let which Mere never filled for various reasons, among vhich wns the very apparent lack of technical experience and information concerning the rnanufncturc of this product. The avaiinble literature on this x b j e c t '~1'23not only woefcily lacking from B technical stnndpoint, but sucii information as t h e literature aroviried *WLS oftcn inislcnciing if thc i-iwiufacturc of picric acid at n rc:ison:hl~ cost, n.ns to bc corieiclcrcci. For exampic, the w i i c r sc:~rciicr! tlic iilcrntuic nvnilnble in many libraries throughout tiik country arid failed to find any esccption to the prcnti1ir:g iwthod of sullonaticg the phenol with one part of 66' EX.sulfuric wid t o one p r t of pheno!, and yet i t is impoF=i!,ic to prodi.ic,e picric ncid of the specifications required for muiiiiior: piirposes, or to procure mywhere near a sctisfactory yield, T!ien the sulfonation is carried en in these pro pori,ions.
pitcher, and pouring it into she crocks in a row used for nitm5ng. This method of transporting liquids TWS then used for the addition of water and finally for the introduction of nitric acid, the n o r h i e n pncsing back s:id forth along the ?OW of crocks, adding nitric acid, a little a t a time, +,ocnch of the s by n, inan at cnch c~ocks. The ngita?ion i ~ a accomplished PLE ACT1oss Isvo LVE.D end oi the rope drslring bnclc nnd forth as they v-0~1~1 operate Frcm t!ie ciicnktry of the production of picric acid, two a crowxi: caw. The lvriter ncvcr s n this ~ p!snC, but !IC has types of resctions are ac?spta!:ie t o priictical applicntion: been tclrl that an attempt t o opcrtitc such nn outfit \\.'a5 actxFirst, tiie riitra;ion of chlorobcnzene with mixed acid: ally maric. C6135CI 3- 2HNOJ CGH3 (I\loz)Sc1 $. 2Hz0 (1 ) 2-In the first plant to come uxder the personal obccrvation The diiiitroc!;lorobcnzcne is ncst treated with caustic soda of the miter, the phenol m s m c l k l in tlic drums in a hot room with tlic i o r m t i o n of dhitrophenol: hca~cclby a steam coil. By t l h mcans it was possible with GO pounds of steaiii to mcit ncnriy d l the phcnol in tliiec 110C&S (1\.'0?)2C1f KaGI3 = CGI-ir (XOz)&X + KaCl (2) The r.ii!iitro~ilicnolis again nitrated with rniscd acid, forming ga;!on drums i n 50 Iiours. T!ic melted phenol was then dro;qmi into cast-iron tsnlcs wit11 GG" 136. sulfuric acid, and pic.ric acid: stirrcd by hand, Tile phenolsuKoiiic acid nns c:inicd by cBHS!xoz)20r~ "i. mio3 = ccFr?(ivo2)m3 + :rzo (3) gravity throtlgh a 2-inch pipe to the nibrating shcd. -4s The second mctliod consists in first sulfo:iat,ing phenol ivith tlicrc as no way of hesting this pipe in cool wcathc:. t h e phenolanlfonic acid solidified bcforc reaclcng t h e nitrating suifcric acid: shed. CpEpOH 3H:SOa CsI-i?(€OzGIl)aOH 4-3IIz0 (4; In :he nitrating shed were large, wooden, shallon., rcctnnguanc! then nltratixig Ciic phenol trisulfonic acid with eitlicr lnr tanks in Whkh mere phccd 15-gdjon crocks with COVCrs nitric or d x c d acid iorming picric acid: having ?>outs leading into a Iatcrd ventilating dilct, w!iich, =I,H,!SOjC)X);Gli j 3HiiO. = C&L(NOd30R f 3H2S0a (5) connecting rvith similar ducts from othrr tanks led into a :~iainvcntihting shsir, fisted \ v i & z i b;o;i-ci. 'TO st PROCESSES 'LiSED crocks viatcr \ m s run into the tanks nnd liectcd by stc3111 From an equipment standpoint two processes hnvc? bcen coils in tlie botton of tlic tanlis. utilized with success--i'iz., thc nitrator method and the pot At one end of each tank were tvo suclion filter., and after method. The nitrator method has been uscd with both the nitration t h e crocks werc dumped into these filters by rneens chlorobcnzcnc an(! plicnol proccsscs, but is more particularly of a trrrvcling thldlasi. The crocks iwre chargcd by liend adaptcd t o tlic iisc of chlorobenzene. On account of the witl: buckets and the nitric acid was Fed s i o ~ l yinto each Frcn.tcr cost of cquipmcn: nnd tlangcr of local overheating, crock by hand wilh ,z pitcher, Tlic ngihtion n*os accomin the writer's upinion t h o pot mcthod j.3 more npplicnblc, glihed Sy mcnn3 of u. 1-inch ghrss rod introtiuccd through a cspcziniiy to -mr-t.irnc conditions, and this article will bc con- hole in thc coi'cr and rotntcd by lintid. A3 will be nnticipatcd fincrl to the ESC of Ihc! 'sot method wit11 phcnol. by the render, no picric acid of any value was cycr produced 1-The first process to come to the writer's attcntiori in tlie in tIGs plant. cnrly days of t'nc w m consisted of two hundred crocks cE 15 3-The first plant obqcrvcd by t h e writer to opcrntc sUCg.zi!ons capscity codi, pI:md in 5 row with a post set in the ccss~"ulIyconqisted of two segrimtc buildings-onc called the "pot lmuse," and onc tlic "wx-11 house." The p o t liotisc WYRS 1 Efcelvcd August 4, 1923, =2
+
January, 1924
INDUSTRIAL A N D ENGINEERING CHEMISTRY
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constructed with plenty of openings for ventilation, and under a line from the sulfonators, where they were charged along each side were placed 50-gallon1round-bottom, earthen- with phenolsulfonic acid and water and then returned to ware pots in boxes and surrounded by cinders or some other the nitrating shed, completing the cycle. The picric acid was removed from the suction filters to insulating material. Through the center of the building and between the two rows of pots ran an industrial railway. Over centrifugal machines placed beside them and still further this railway the phenolsulfonic acid was brought to the pots washed, then whizzed to approximately 10 per cent of water. and later the picric acid produced was carried to the wash house PROCESS PREFERRED BY WRITER over this same railway. Above each pot was placed a carboy The accompanying sketch represents the design of a picric of nitric acid, and after charging the pots with phenolsulfonic acid aad diluting with water, a number of men entered the acid plant made by J. W. Percy. This design, with some modipot house with glass siphons filled with water, introduced the fications, represents in general the writer's idea of the most sucsiphons into the carboys of nitric acid, and so started the flow cessful arrangement for producing picric acid by the pot of nitric acid into the pot. The pot house was then left to met'* '. 3 is the room for the melting of phenol. Th, its own devices until the next day, when the men entered drums of phenol are piled in this room and heated with direct with another set of glass siphons by means of which they steam. 1 is a standard cast-iron sulfonater of 2750 liters drew the spent acid into gutters placed along the base of capacity, equipped with an agitator and steam jacket. From the pots and which drained into a catch basin. The picric the measuring tank, 2, which is about 120 cm. in diameter acid was then removed by hand to a car on the railway and and 150 em. high, the sulfuric acid is introduced through the pipe IC. The tank is refilled from the storage tanks by the carried to the wash house. In the wash house the picric acid was run through rolls to pipe 2a. The melted phenol is poured into the sulfonator break up the large chunks and then placed in a slurry tank through the funnel la. This mixture is agitated at 100" 0. where practically all the sulfuric acid was washed out. After for 12 hours. It is then blown by compressed air through this the picric acid was placed in centrifugal machines and the pipe l b into the nitrator 4. This nitrator is constructed whizzed until it contained not less than 10 per cent of water. of acid-proof brick and Duro cement. It is about 180 em. 4-In another plant 50-gallon earthenware pots were placed in diameter, 2.75 meters high, and of 5500 liters capacity. under hoods for ventilation, the hoods being back to back, 5 is the nitric acid tank of 1600 liters capacity and of similar each pair using the same stack. There were fifty of these construction as the nitrator. The gases given off are carried double hoods placed down the center of a long, narrow nitrating away by the stack 4b. 4a is a trap door through which the shed, and above them were crocks for nitric acid which were final hot mixture may be stirred by hand to prevent caking. charged by gravity from the floor above. The nitric acid This is done when the picric acid first begins to form on the crocks were fitted with earthenware cocks through which the surface. The mixture through the pipe 4e is dropped into flow of nitric acid was regulated through glass tubes into the slurry tank 6. This is a wooden, lead-lined tank about the nitrating pots. This arrangement was advantageous 180 em. in diameter and 4.6 meters high, equipped with the in that the cocks were placed about 2 inches above the header 6a. Water is added and after the crystals of picric bottoms of the nitric acid crocks, allowing space for the acid have settled to the bottom the spent acid is drawn and deposit of sediment, and also, in the same way the trinitrothrough regulating of the flow phenol is washed several times of nitric acid, the nitration with water. When the wash could be better controlled. water is free from sulfuric acid the picric acid is sluicedinto the Shortly after the addition of the nitric acid the picric acid centrifuge 7 , which is of the begins to form a crust on the bottom dump type. At the opening 7a the finished product surface of the liquor and at this time the contents of the pot are is received to be disposed of as given a brief agitation with a desired. wooden paddle. If the crust In the writer's experience again forms it may be necessary the proportion of materials to repeat this agitation as which gives picric acid of the many 8,s three times, although highest melting point and the generally once or twice is all best yield consists of 100 kilothat is necessary. The picric grams of phenol, 500 kilograms acid then commences to crysof 66" sulfuric acid, 400 kilotallize :tnd build up a t the surgrams of 42" BB. nitric acid, 240 face of the liquor. kilograms of water (added to The nitrating pots were then the phenolsulfonate). The sulcovered and moved by means fonation should be carried on of a barrel truck into a warm for about 10 hours in closed room, where they were allowed cast iron tanks fitted with t o stand for 24 hours. During agitators and a t a temperature this time the nitration was comof about 98" C. pleted and the pots were cooled The addition of the water to practically atmospheric to the phenolsulfonate in the temperature. They were then nitrating pot raises the temremoved from the waiting perature to about 70" C., which room to the suction filters in is the ideal temperature a t which f he picric acid was filwhich to start the addition of tered out and washed. The the nitric acid. The flow of the DZSIGNOF P I C R I C ACIDPLANT empty pots were then wheeled nitric acid is started slowly and w = Water; a =Air; s = Steam
fl
I N D U S T R I A L A N D ENGINEERING CHEMISTRY
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maintained at the same rate for 20 minutes, when the temperature of the nitrating liquor should be in the neighborhood of 125" C. From this time on the nitric may be added as rapidly as possible and should have completely entered the nitrating pot within 1 hour. The foregoing is only general, as the rate of flow of the nitric is best determined by practice. The procedure outlined above has given yields as high as 220 pounds of picric acid having a solidification point of 120" + C. to every 100 pounds of phenol used. The average yield should exceed 180 pounds.
Vol. 16, No. 1
If nitric acid is manufactured at the plant where the picric is being produced, it is better to nitrate with straight nitric. If, however, the nitric has to be shipped in, it is better for transportation and handling reasons to substitute mixed acid for the nitric. The mixed acid should have the composition of sulfuric acid 1part, water 2 parts, and nitric acid 7 parts. The ratio of phenol to 66" BB. sulfuric for sulfonation should be changed t o 1:3.
Catalyzers for t h e Oxidation of Ammonia' By Wilfred W. Scott COLORADO SCHOOL
OF
MINES,GOLDEN,COI.0.
A list offifty-two substances, elements or compounds, used by the author for catalytic oxidation of ammonia to nitric acid are gioen in their order of efficiency. The influence of certain substances added as accelerators is indicated and seoeral additional examples are gioen of substances used, showing a marked increased eficiency due to their presence. Cobalt has proved to be one of the most eficient elements, and in combination with small amounts of added substances rioals platinum in efficiency as a catalytic agent f o r oxidation of ammonia. T h e e&ts of beryllium, cerium, bismuth, thor i u m , nickel, ascertained in recent experiments, are shown and a comparative table given. Bismuth appears to be the most efficientaccelerator f o r cobalt; the amount, howeoer, should be kept within certain limits, as large amounts of bismuth will f o r m a n easily fusible alloy andamounts less than 0.1 per cent are not eficient. A good combination is 97 parts by weight of cobalt oxide and 3 parts by weight of
bismuth oxide, though this m a y be varied within fairly broad limifs. Several substances apparently improoe with use and are not so easily poisoned as is platinum. The fixation of nitrogen is one of the most important achievements of modern chemistry. T h e demand of the f o r m of fixation will depend upon the state of war or peace. I n time of war the balance will swing towards nitric acid o n account of its use in explosives; in peace the proportional demand f o r ammonia and its compounds will exceed that for nitric acid and explosioes. Whether in peace or in war we are dependent upon the products of fixed nifrogen-ammoniacal nitrogen f o r the production of our food supply, nitric acid and its derivatives f o r our national security. T h e great source of raw materials f o r the making of either has n o monopoly-free air and water, available fuel, and catalysts that can be obtained in abundance and at low cost.
URIKG the first two years of the World War the au-
Many of these tests, where pumice was used, may be in error from the light of more recent work, since silica combinations occurring under the intense heat of the reaction undoubtedly influenced results. It is worthy of notice that conversions as high as 93 per cent were obtained with metallic platinum a t a temperature of 200" C., which is far below the temperatures used a t the Government plants in their experimental work. Platinized asbestos was found to be a poor catalyst. A short duration of contact of the gases with platinum was necessary for good yields (0.007 second or less). The influence of small amounts of substances in increasing the activity of catalytic substances has been noted by a number of investigators. In previous work on this interesting feature of the subject the writer tested out the effect of added substances as promoters for iron, nickel, and cobalt, the following elements being added in small amounts to each of the elements mentioned: aluminium, antimony, arsenic, barium, bismuth, calcium, chromium, copper, lead, lithium, magnesium, manganese, molybdenum, osmium, ruthinium, strontium, tin, titanium, thorium, tungsten, uranium, vanadium, and zinc. I n the majority of cases the addition was of very little effect and in some cases actually detrimental. The following combinations, however, gave good results : Iron with bismuth resulted in an increased efficiency of more than 20 per cent over the oxide of iron alone; bismuth added to nickel increased the efficiency of nickel oxide 63 per cent, added to cobalt it increased the fficiency of the CObalt oxide over 8 per cent; aluminium h d very little effect as a promoter for iron or nickel, but it increased the efficiency
D
thor was engaged in researches relating to products used by the Allies, and more especially in investigating various substances for ascertaining their efficiency as catalysts in the oxidation of ammonia. During this period a large number of substances were compounded and tested. Pumice was used as a carrier where it was not possible to use the substances direct or where bulk was desired. A list of the more important of these substances based as catalyzers is given in the order of their efficiency as found by the writer: Bright metallic platinum gauze Cobalt metal (surface oxidized) Cobalt oxide Iron oxide Metallic silver Metallic nickel Silver vanadate Copper uranate Cobalt chromate Palladium metal Iron manganate Platinum-coated iron gauze Nickel chromate Stannic oxide Vanadium oxide Silver manganate Iron arsenate Silver arsenate Nickel vanadate Nickel manganate Copper molybdate Silver chromate Cobalt manganate Chromium oxide Iron vanadate Silver molybdate
Nickel oxide Manganese dioxide Silver oxide Copper vanadate Copper tungstate Metallic copper gauze Silver uranate Copper vanadate Iron molyhdate Iron tungstate Copper arsenate Nickel arsenate Cobalt arsenate Nickel molybdate Copper chromate Copper molyhdate Oxides of copper Gold Titanium Uranium Barium Lead Iron uranate Nickel wanate Cobalt uranate Nickel tungstate
1 Received April 30, 1923. Extract from thesis presented in partial fulfilment of the requirements fcir the degree of doctor of science.
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