INDUSTRIAL AND ENGINEERING CHEMISTRY
July 1947 \ 011E\
C LATURE
.I= ,, au~fac~c, area oi >iiray droplets in tower a t any tinie, .q. ft. A , = surfac>earea of wett,ed wall, sq. ft. b = tliffusivity of solute gas, consistent units Ci, C2 = constant coefficients in ronsistent units r of spray dropleb, mic.wii-
gas flow rate through duct a t toxyer entrance, 1)). mole.* !niin.) (sq.ft.) e loss across cyclone, inches oi watei, re expressed as number of entrance velocity head. K , , ~= niiis- transfer coefficient for spray droplets, 11). nioles ' j n i i n . ) i s q . ft.) (atm.) K , ,, = nia+ transfer coefficient for the wetted wall, Ib. moles: [niin.) 'sq. Et.) fatm.) L = liquid rate, gal.;niin. w , (1 = expnnential constaiits n = numher of nozzles = n u m h ~ . of r transfer units on spray surface &VT = total iiuniher of transfer unit:: in tover S,, = numher of transfer units on \retted vial1 5urface p = partial p r e ~ w r eof solute gas, atni. Subscript 1 refew to inlct gas, subscript 2 to outlet gas, anti aqtrriik to equilibrium preysure R = distanre from center of tower, ft. S = c.ro~s-sectiona1area of gas inlet, sq. ft.
G
=
rt at ton-er entrance, f t . miii.
817
I', = gas velocity near the na11, ft. i n i i i . = total pressure of qns, atni. = density of air, l h ~ m ft. ~. p u = viscosity of air, ronsist,ent u n i t %
T
LI1'ER.ATURE CITED
(1) .Ilden. .J. L., Ht,fii/iy oliri T ' t t f t i / f i t ; r ( y 35, 4& (1935,. ( 2 ) - h t I i o i i y , A . I\-., J:.. (.o Pease-hnthon? fcliiipincxit Co.), U. S. Patent 1,986,,013(Jan. 8, 1 0 3 5 ~ . ( 3 ) I / ) i d .2,155,853 f,.kpr, 2 5 , 19391. ( 4 ) 16id..2,281,261(?.pi,. 2 $ , 1942). ( 5 ) Anthony, 1. K , JI ., private ro~iiiiiuiiication,AIarch 1946. (40) Chilton. T. H.. a n d Colhiirri, A. P., IND. E m . CHEM.,26. 1183
(1934). ( 7 ) .John3tone. H . F., :mri Kl:~iiis-titi~idt, l t . I,., T r a m . Am. Znst. Chrm. Engrs.. 31, 1'11 (19381. (8) Johnstoue. H. F . , aiid Yingh. h. I ) . . I Z D . l h c , (''HEAI,, 29, 286 (1937). (I)) Kleirisehinidt, I t . \',, ('hem. t t .\Id. Eng.. 4fj, 4h7 (1939'1. (10) Kleinschriiidt. 11. V., and .hthotiv, A TI-.,.TI... T r a m . .am.S o r . M ~ c h Engr,?., . 63, 349 (19.11). (11) Pea-e. F.F.. C . Y. P a t m t 1,99:!,7~i2 ( l . e l ~2li, . 1'1:45]. (12) Shepherd. C. B., a n d Lapple, C ' . I-:., I N D .l:scl. H HI:^,, 31, 972
(1939). 11X I'tid., 32. 12440 (1940t. (141 Silcox. H. E., Ph.D. t h e i s , I-iiiv. of Ill., 1942. PRESESTED before t h e Di 111 of Industrial and Engineering Pheiiiiitry a t rhe 109th l f e e t i n g of t h e . l \ r a ~ r r a v~ H F ; \ I I C & LS O C I E T Y , .Atlantic City, N. .1.
Vapor-Phase Nitration of Saturated Hydrocarbons J
H. B. HASS AND H. SHECHTER' Purdue Cniversity and Piirdiie Research E'oicndation, Lafayette, I n d .
S
I S C E 1930 considerable interest has been directed toward developing a new unit process, the vapor-phase nitration of aliphatic hydrocarbons. As a result the Commercial Solvents Corporation established a n efficient industrial process for the production of nitromethane, nitroethane, 1-nitropropane, and 2nitropropane by the reaction of nitric acid and propane a t temperatures above 400' C.; recently Imperial Chemical Industries, Ltd., announced the availability of these four nitroalkanes. On the bn4s of the investigations tvliich have been conducted at Purdue University and in many other laboratories during the past sixteen years, it is now possible to generalize about ninny of the complex actions of the vapor-phase nitration reaction. .Is a result a number of empirical rules based on quantitative experimental evidence have been formulated which characterize the reactions betn-een the various nitrating agents and saturated hydrocarbons. RULE 1
If pyrolytic temperatures are avoided during the nitration of alkanes or cycloalkanes, no carbon skeleton rearrangements occur. This rule is in harmony with the corresponding one for the monochlorination of alkanes. Sitration temperatures usually range from 150" to 475" C., and thus pyrolysis of the parent hydrocarbon does not constitute one of the principal high temperature reactions. However, coneiderable decomposition of the various nitrated and oxidized compounds occurs and results in the formation of olefins and degraded products. For example, pyrolysis of nitroethane and 1-nitropropane yields olefins, alde1
P r e s e n t address,
The Ohio S t a t e Cniversity, Columbus, Ohio.
hydes, carbon monoxide, carbon dioxide, and nitrogen but no loner nitroalkanes (18). The data presented in Table I indicate t h a t nitration of 2,2dimethylpropane, 2,2-dimethylbutane, 2,2,:3-trimethylhut:u1f~. and cyclopropane yields no product's resulting from structurd isomerization. Since nitroneopentane is obtained from neopcittime and neohexane, the reactions producing hydrogen or nll
