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INDUSTRIAL AND ENGINEERING CHEMISTRY 20
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12 .*YIELD O~CONVERSION CONTACT TlMEm0.27-0.285EC. LU I
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Vol. 39, No. 7
from the, volu~neof the exit g t standard teniperaturc and pressure, and delivery of the 65.lC'; nitric acid is expre niillinioles of HK0,3. Figure 7 illustrates the effect of tempcraturc on the yield and conversion at an exposure time of 0.27-0.28 second. Ai niaximum coriversiori of lS.Sci, hesed on nitric arid delivtartd, was otitaincd et 465' C ' . and a methane-nitric acid molc ratio of 20.1:l. Siricc thc conversion \\-asnot greatly affected by temprratur ' changw iwtn-ecxn l6Oo and 475' C., it is evitic,nt that a 1::rgc section of the reartor served 2,s a preheatw p.nd vaporiztbr. 7 alw shoi\-s the effect u i teiiiperature 011 thc j-idd and .d a t x n exposure time o i 0.49-0.56 second. A ion of 18.7c; \vas obtained a t 160" (". and a it1 retio of 19.8:l. The increase in c.x-posure time did riot effect the yicld appreciahl>-. Thew expc~imc~iita werv discontinucil since it seemed probable can tJe operatctti moly c4ficiently at lower prt:ssur^ :inti in I c w complex q u i p m e n t . (1
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TE M PER ATU R E 'c . Figure i. Effect of Temperature on Nitration of 3Iethane a t 1000 Pounds per Square Inch Gape
LITER.4TC-RE C I T E D
( l ! Boyti, T.. &lidI%&--.H . B.. ISD. ESG. CHEM.. 34, 300 (1942). ( 2 ) Hnbs. 1 % . B.. Ilodpe, E . B.. and Yaiide~hilt.B. ll,,ICid.. 28 339-44 (1936). \:3) FIRIS. I I . B.. Hodge. I:. R..arid \-aiidei.bilt, B. SI., U. 9 . Patent l , ~ I ~ i 7 , 0 0(.Jul\. 7 24, 1034): R i i t . Patent 443,707 (.June 30. 1937); Caiiadimi P a t e n t 3T1.007 (Jan. 4, 1935).
T o (.lit1 an experiment, valves 11 arid 37 w c ~ wopcLncd, v:tlvc~~ ( 4 1 Kollie, 13.. J . praX.1. ('bun.. 5, 427 (1872)). 2 , 3, and 13 were closud, and the reactor gases were p u q y d ( 5 ) Landoil. C . K.. U. 3 , Patent 2,161,475 (June 6, 19391. through the condenser system. The product in receiver 2.5 \v:ts (6) I l d . , 2,164,774 (July 4 , 1939). removrd through valve 26, combined with the liquid in triips ( 7 j Hideout. 0. JV,, U . 8. Patent 2,291.345 (July 28. 19421. ( 8 ) I\-einier, It. It,, "Thermochemical Cslrulationh," 11, 221. New 32, 33, 34, and 36, and then distilled. The nitric acid \vas T n i k . 1IcG1a1v-Hill Bonk Co.. Inr., 1941. drained from the reservoir through st,opcock 17 and tlirn n-c.ighcd E F F E C T OF VARIABLES ON TITRATION RE.ACTIO>
TYPEOF -\PPARATCS. .4n experiment was coriducted at it gage pressure of 100 pounds per square inch in order that a comparisoii of the efficiencies of the metallic and glass riitration system> might be made. The data and results are listrd in T a l ~ l c1-1. (The contact time reported for experiment 1 is high hecause part of the reactor served to preheet and vaporize the reaction mixture.) Because the average loss in removing end analyzing the products from this complex apparatus was 8.jc;, based on riitromethane recovered, the total nitromethane obtained in each (1speriment was calculated by dividing the w i g h t of the recovc.retl nitromethane by O.Sl5c;. Since the conversion in cqwrinieiit 1, even though conducted at a more unfavorable rsposure timc, \v:w only slightly less than those obtained in experiments 2 and 3, it was concluded t h a t the metallic apparatus had functioned e%ciently a t a gage pressure of 100 pounds per syuare inch. 1101.~RATIO. A conversion of 9.1c-i\vas obtaincd at 460" ('., a mole ratio of methane to nitric acid of 9.6:1, end a gage pressure of 1000 pounds per square inch. K i t h a hydrocarbon-nitric acid mole ratio of 17.2:1, the conversion was increased to 18.7 per cent. Those results show that the nitration of methane is more difficult to control at 1000 pounds per squaw inch than a t loivcr pressures: therefore, the remaining expcrinients \yere contiacted with e mole ratio OS methane to nitric acid of at lrast 16:l. TENPERATI-RE ASD COSTACTTIME. T ~ v oseries of cxpe:.iwere conducted at exposure times of 0.27, 0.28, and 0.4!)0.55 scxcond, respectiv Iy, to detcrmine this maximum convorsion of n'tric acid to nitromethane. Table VI1 is a compilation of the data, obtained from this invc,stiga,tion conducted at tempc~raturcs ranging from 450" t o 475" c'. llcthani: delivery \\-as czlculr:tctl
Calculation of Number of Theoretical Plates for Rectifying ColumnCorrespondence SIR: Attcritiori has been called t o t h r reccint \vork of riitler\vootl (3, 4)ivho derived equations somewhat similar t o those, oht a i n d i)y the author ( P i Sor calculating the numhrr of plat(% r e q u i r d Cor thr. rectification of ideal biliary mixturw. 17ndilr\voodshould be given priority c r d i t for the O ~ J that the use of the two intersections oi operating line and cquilibriuni curve of the extcndetl llcC'abe-Thic~lediagram leads to an cquiLtiori some\vhat simpler in Sorm thnn the equation originally obtainid hy Sniokrsr (1) who worked \vit h only on^ intersection. The author also used thcb double intrrcept concept but a iomc\\-hat different method i ) f derivation. It is not surprising that all three equations (1, 2 , 4)may be skion-11 t o tie identical. since thc re analytical solution> of t h r sznie problem. L I T E R 4 T U R E CITED
(1) Stiiokei,, 1;. H , , Trans. A m . Inst. Chem. E w r s . , 34, 165-72 ( l : f 3 8 ? . ( 2 ) Stoppel, A. E . , ISD. E s c . C'HEK., 38, 1 2 i l - 2 (1946). (3) Underwood. A . 3. V., , J , I n s t . P ~ f i o i r i i m29, , 115-56 (1943). (4) Ihid., 30, 225-42 (1944). .\, Y S I I F.R,SIT\ O F > ~ l S S E i C l T . 4 1 1 I IY E* P(,I.IS, >II ss.
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