.1,896,627 component solutions, but when the proportions are varied care should be taken that after the reaction is completed the base exchange bodieq remain strongly alkaliiie to litmus and preferably neutral or alliali-ne to phenolphthalein. The components used in formiiig the nollsilicious base exchajige bo,-Iies iiiay be citalytically active or activ,,tting, or tl-iey inay 10 possess the character of stabilizer proluo@ll @ers. In all cases they are coiiibined iii the no.-,Iexchaligeabl@e iilicleu I s of tl-ie col-nplex be,,se exchange niolecule in a @orm in which their efficiency for the catalysis is very high. 15 In this example diluent bodies are elllbedded in the base exchange bo-dies by the preferred method that is to sa the,y tre y formed in situ, but iindiluted base excliange bodies may also be used effectively for the oxidation of ammoiiia. For eco-non-i,:c I ai pro. . duction of contact i-nasses, howe-@,er, it is vantaaeous to el'i'lbed diluents therein. Partictila;ly desirable diluents are those coiltaining oxides of the M-Itals of the iron gro-tip with or without smaller amclints of rare earth metal oxides. By the proper choice o],c the component solutions used in forininu tl-ie contact n-lasses it is possible to obtain products havino- a very great resistaiace to the high temperatures which are encotintered in the reaction. Exa,inple 4 (1) A 10@'o soclium alumihate so'Lution is prepared containing 20 part,--- of Al 0,. (2) 10 parts of basic copper carbonate are dissolved in 5@'o ammonia, ivater to foriii the cor.responding cuprainnionium conipoulicl. (3) A IOTO solut'on is prepared coii,',a,,ning a mixture of Om m e chr iu and iron nitrat in '%Vhich the proportion of Cr,03 to Fe,O,, is approximately 1 to 5. The alum;.nate and cuprami-ii0niLlill S61utions are poured togetiier and solution (3) is then added until the inother liquor of the reaction product jus'u remains s'lightly EL!kaline to phenolphthalein. The precipitate obtained is filtered off, washed with water and dried. The product is leached as described in flie foregoing exampl-'s and is then pulverized and coated onto iron oxide granules or pieces of unglazed porcelain Lising calciuiin or i-nao,r, nesium compoui-ids as adliesives. The conE5 tact mass thus prepared is filled into a suitable converter, and a mix'L- Lire of amnionia and air contaiiiing 5-7To of alumonia, by volume is I)assed over at 600--SO,O" C., goocl yields of oxides of nitrogen beinly obtained. CO The coiit,,tct rii-cisses which co-.it,,,,ii, vada,dium, for example wheii a vanadite or vanadyl sulphate is a coinponent, are well siiited for the oxidation of aminoni,,t which contains impurities such as sulphur: bodies, phenolic fj5 bodies and the like, as is the case f or example with ammonia pr oduced as a by-product in the distillation of coal tar or si@nilar tars. The impurities are oxidized to products which are harn-iless. The contact mass may be used as a coiiiposii"e contact iiiass and the TO ptirific,,ition a-,qd amiploni-i oxidation may 'uake place si-ii-itiltaneotisly. I'l desired the co,ni'act rtiass luajr, hov7ever, be tised as an amnionia plirification contact mass as when the temperatures:are iiaailitained at a lower 75 poi--Lit, ioi- ex@niil,le 400-4500 C.1 the same contact niass, or those described in the forelai-t of the pr6sent or in Example 4 niay be useci for th,,, second stage in which the amI'@10111a ls oxidized to niti-ogen oxides, thfs reacti-on of course takii i iz L place at higher temperatures. I ' n the claims the t6rin "permutogenetiell cov6rs bas@ e I xchano-e bodies, silicious or nonzn silicious tile products obtained by the acid 1 lea6hing of these base e-vehange bodies and ti-ic s,,It-like bodies obtained by the reaction 6f@ these bas-, excha.-i(re bodies with coinpound ihe a6ld radic@als of which are capabie of reac'cing the base exchange go -IDodies to p:rodtice prodticts which show most Of thepro@--rties of salts. When so used iia t!,io cllims, the tern-i "permutogenetic" will have iio otlier rneaning. Wh-at i clain-ied as new is: 95 1.@'A inetliod of oxidizing ammohia to oxides of iiitrogeii, wliich c prises pa . ssing Om -iia i aiiiiuoi dmixed with air at an elevated tenip-@r,,Lture over a contact iiiass containing an adicl leached b se exchange body. a .100 2. A iiiethod of oxidizing ammonia, to oxides of iiitroge-u, whicli con-iprises passing ainii,ionia adinixed Nvitl-i air at ali elevated to@nperature over a cojitact mass containing ,n @cid leached hoiiiogeneously diluted base @105 exchaiige body. : 3. A inethod accorc[ing to claiin 1 in which at least one of the c@talyticall-_v effective compoiiell,6s is I)r6selit ill tlle contact inass chemi clilly co mb ned in the base exchange body. 110 4.'A iiietiiod according to claim I in ivhich at least ope of the cataly'.ically effective com ponents is present i-@i th,- contact mass chemlically colubined in the base exclianze bod y iii non-exchangeable -.Iorin. 115 5. A ir@ethod accordi-ii g to claiih 2 in Nvhicli at, least 6lie of- the catalytically @.ffective comp n's is preseiit - the coiitact mass chemoiie icaliy coiaibineci iii the,base exchange body. I 6. A niethocl ace6i,dillF, ,o claiiii 2, in whicli 120 at leas4.- op-e oi the catall,tically e:ffective coiilponents is prese-n-t" iii the contact ihass cheini.ca'LIv combiiied in the base, exchange body in not-i e:@,chaiigeable form. 7. 7 A n-iethocl accorcl @lng 'Lo claii-n 1 i.-i wh4leh "-25 thc, co@-itact I-nass coiitaiiis iron oxide. S. 1.1'1 the ox@dation of iinpure ainmonia coii'Llaining cxidizable impurities, the step ivhich con-il)risc-s bringing about reaction betwee-ii the ptire -@miiaonit ,tnd air at an ele-

1,896,627 vated ten-iperature in tl-ie presence of a contact n-iass containing an acid leached base exchange body which f avors the selective oxidation of the impurities. 9. A iiiethod of oxidizing impure aiiinionia coiitainiiio- oxidizable iliipurities, which comprises passiiig the mixture of the amiiionia aiid an oxygen contaiiiin- gas over a contact mass which f avors the selective oxida10 tion of the implirities but Nvhich cloes liot favor the oxidation of aminonia at the ten-iperature used, aild theii passilig the purified ainmonia adiiiixed with air over a contact iiiass favoring the oxidation of aiiimonia, at 15 least oiie of the contact masses contaiiiing a leaclied pernlutogenet;-c body. 10. A iiie'Lhod of oxidizing impure amn-lonift containiiig oxidizable inipurities, whiel-i comprises passiiig the inixture of the ammonia 20 aiid an oxygen containiii- gas over a contact ii'lass Nvhich f avors the selective oxidation of tl-ie impurities but which does iiot favor the oxidation of aiiimonia at the teiiiperature used, aiid then passiing the purified 25 aiiiiiioni,,L admixed v,,itli air over a contact iiiass favorii-ig the oxidatioii of amiiionia, at least one of the contact n-i,,tsses containing a leached diluted periiiutogenetic body. 11. A niethod of oxidizing impure am30 iiioiiia containin(,- oxidizable ilapurities, el which con-iprises passina tho mixture of the ai-iiiiionia and an oxygen containin(y gas over a contact i-nass whicli f avors tl-ie selective oxidation of the, iinpurities but which does not 35 favor the oxidation of ai-niiaonia at the teiiiperature used, aiid then passing th(,, purified amiiioi-iia ,Ldiiiixed ivitli air over a cont,,tct inass favoring the oxidation of an-imoiiia, botl-i of the contact iiiasses containing leached 4.0 periiiutogenetic bodies. 12. A inethod of oxidizii@g impure aiiimonia containiiig oxidizable impurities -which comprises passiii(y tlile iaixtiire of the ain@n inoni,i and an oxygen containing gas over 45 a, contact mass which favors the selective oxidation of the impurities but which does not favor the oxiclation of aniinoni,,t at the, teiiiperature used, and theii passing the purified aiiirnoiiia admixed with air over a con50 tact n-iass favoring the oxid,,ttion of @tmmonia, botli of 'u-Iie contact niasses containin- leached diluted I)ermuto(yeiietic bodies. 13. A iiiethod according to clain-i I in whicli the contact mass contains a compound of 55 vanadium. 14. A iiiethod according to claim 9 in which the contact iiiass for the oxidation of amn-ionia contaiiis a compound of vanadiun-i. Signed at Pittsburo@ll, Pennsylvania, tl-iis r'O 20tli day of March, 19 9. ALPHONS 0. JAEGE, R.

Patented Feb. 7, 1933 19896@627 UNITED STATES PATENT OFFICE ALPHONS 0. TAEGER, OF CRAPTON, PFNNSYLVANIA, ASSIGNOR TO THE SELI)EN COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPOR@ATION OF DELAWAP.E CATALYTIC OXIDATION OF AMNONIA No Drawing. Application filed March 22, 1929. Serial No. 349,275. This invention relates to the cataiytic oxidation of ammonia to oxides of nitrogen. In the past ammot-iia has been oxidized to oxides of nitrogen at elevated temperatures by means of air or 6ther oxidizing g,,tses in the presence of contact masses, usue@lly platinum gauze. The present initention is dirceted to the catalytic oxidation of ammonia in the presence. ol' a new class of c6ntact niasses. The contact masses used in the present invention are the acid leached products of bise exchanging bodies, either ze6lites or -nonsilicedlis. The base exchange bodies which are acid leached may be of the ordinary +@wocomponent zeolite type, that is to say tli@-, reaction product of a. silicate witl-i either one or more me',-allates or one or more inetal salts, or they may be multi-com onent zeolit-'s which ,tre the reactioil products of a'L. leist 29 one silicate, at least one i-netallate and at least one salt the bas-ic radical of which is a metal ca,pable of elitering in@o the non-exchaiioeable nticleus of a zeolite. The unleached inult@-1component zeoli.tes, diluted or undiluted, are 25 described in my prior Patent No. 1,728,732, dated September 17,1929. The nonsiliceous base exchang-- bodies are described in my prior Patent No. 1,694,122 dated December 4, 1928. 3( The base exchange bodies or their derivatives produced by introducing other bases by base exchange or . by caus; no, the base exchanue body to react with a compotind coiitaining an anion capable of reacting therewith to forill 35 a salt-like body -will be referred to ger@erall@y as 4@ permutoge@etic bodies". The catalytically active conipoiients iiiay be associated in or with the permutogenetic bodies, di.l'uted or tindiltiated in five main 40 forms:-(l) Tliev may be hysict,,Ily adp mixed or impre na@ed into the periiiutoo,enetic body. (2) They may be physicarly, hom6geneotisly iiicorporated into the pernautogenetic bodies before the latter have 45 been . coiiipletely formed, acting as catalytically activo diluerts' or diliieiits which have beeii impi,eo-nated with catalytically qclc-ive substances. (3) They na,,@y be cheinicaII37 combined in the permutogenetic body in non50 exchangeable form, that @is to say tl-ey may f orm part of the non-exchangeable nucleus of the pei-mutogenetic body. (4) They may be chemically combined in eichangeable form either durinz or after formation of the permiitogenetic body. (5 They maybe Chem i- '56 cally combined with the permutogenetic body in -the f o,rm of catalytically active anions -which have reacted with t-he base exchange body to form a salt-like body. Obviously, of colirse@ the ,ame or difterent catalytically @6-@ activ,@ compoiient.s may be present in more than one of the above described forms, and it is an advant,age of the present invention that catalytically active substances may be introduced in a wide variety of forms -Which 65 gives a wide f-- .eld of cl-ioice to tlie catalytic chemist. :Wliile four of the methods of combination of cat-alytically active substances may be@ effected With -Lindiluted as well, as diluted per- 70 mutogenetic bodies, I have found that for th(3 catalytic oxidation of amraonia the diltited peirmutogenetic bodies present many advantages, particillarly where the diluents are of a physical nature stich as to exert a desired 7,5 intluence on the catalytic activity of the contact -masses as when, for exam le- the diluents @ p I by reason of high porosity capillarity or surface energy may be considered as physical catal.ysts or activators. 8,0 The permtitogenetic bodies described above are treated with, dilut-e acids either mineral or organic and this leaching process renioves part or all of the exchanoeable base present which is usually alkali or if carried further, 85 part of the basic portion of the nucleus of the permiito-uenetic body is lil@cewise removed. Contact masses of remarkable effectiveness are thus obtained by reason of the desirable phy-ical struct,-Lire of the leached permiito- 90 genetic booies and the wide limits of homogeneous diluti6n 6f catalytically active molecules with re@Liltinv@ uniformit@ and smoothness of actioii whi-@h is of oreat importance. A-nother important advantage of the con- 95: tact masses coiitaining leached permutogeiietic bodies lies in the f act that these contact masses are extremelv resistant to high temperatlires, especially when most or all of tb-e exchaiigeable alkali has been leached out. As lo(

the oxiclation of ammoiiii reqtiires very teiiiperatures, this characteristic of the coiitact masses of 'uhe 1)reseiitL-ivei-i'ui.oi. is of (yreat practical importance. The leachila(, of the I)eriiiuluo-eii(-,@u-ic boclies zn tn transforms excliaii!D ,@eable tlkali iqfo coiiipounds of the alkali-formin- iiiet,,ils @vliieh n act as stabilizers for "he i-e.Let;.oii. stabilizers may be noii,,tlkaline, .Lll@a10 line, or stroiioly all@aline, depencliiio- , on ,-he exteiit to -which the leael-iiiio- ip, ou"-. Tii adclitioii to the presence of,v,,hicli ,ircN iiii-I)ortaiit in coniaectioii Avith iiiany of the cont,,tct iiiasses used in the prosei-tt i,,ivention5 it has beel-i fouia(l tlo at the stabilizer action ai-id the overal'Iefficiciicy o@'L 'u-i-le coi-itact m,.Lsses cin iii @@iiiilv cases be, -Iicreased or eiihqi-iced by @he - ssociat;lon 'L"with or chei-nical coii-ibiiii'ui,,)Ti o'L el,--- 20 iiieiits or radicals or (-ro-,iT)swhich,,irec,,i-ql@,,tically active 1- )Lit -which do iiot poss,,@ss s,,)Qcific cat',Il XTtic activity for the oxiciatioii of oxidec, .1 of nitro(ren. Thiis, for i' lyil'; '@l@ iioted that the reaciioii iiivolve-s the -t-li7oclue25 Lion aiid splittiiig of-r of iv, atei,. Fci, i-ei - son it is desiribl@'in mii-iy o'L coii i- ii,-t iiia,@scompositions of the presei,'L- ;-,ivei-itioii 'L-o ii,corporate or inel.ude catal)7s'us or ca'L-al., yt-jcomt)onents -wliieh are r@ot sl)eeitic - cat,)I,)IS'S 30 for ilie oxidatioii o'L aminoi-iii 'L-o the of iii.trogeii btit wl-iieli .- ii,,Lv f,,ivor tiori. In other caso,,,@ clifr@reiit iiop.-sT)'ecifi@-, c,,italysts m,,i-v be iised ind ar(,, of Thi-is, for example, -when coal tLr -ammoiii,,i 35 is beiiiy oxiclize(l, it. ;s i-iec.-,ssary to biiri-i o-L,,'@ the organic ii-npiii-i4uies preczejit-,(ii-@d iv',iile sori-io catal,itic compoi,,ei-Lts -wh@leli ,ire oxiclizei'S of ammonia to oxiclc-s Of -Llitro(,On @-ilso f ,Lvor 'uh2 selective, c,,it,,ilytic combtisl-on of or(rinic iiyi40 p-Lirities, iii otlier cont,,ict masses coiiipoi-iei-itF, rnay be incorporated wliieh f avor the selective catalytic coii-ib-tistion of orgtilic impurities or their transfori-i-iati-o-i i-,,ito coiiil)oiliios which ftre h,,tri-iiless or -qsiliT fi,or,,i 45 the final procliict, Aihicli c,-'Mi @@i-ieiit i@-i,,iv iiolu be specific c,,.t,,)Ivsts for the o-f @immonia to oxide@ i-f ritro(-eii, ,l,+@ lef@Ft a"-, tl,o reaction teml)erati-ires i,,secl. Tn this co-,iiiectio--q it shoul(l be notecl tli,.it crie,-tii-onQgs 60 of differeiat c,.italyti,- comi)o-ieits -,Vill l,qr), with the teniperatiire at iA-7L-icb t,@ikes place ,incl that it otic component ma,, be ,L s-@@ecific cat,,tlv-st Avlereas at another fr@eileiiti@, a 85 reaction temperattire, tl@e coiill)onent may no loi-iger be a s-I-)eclfic ca'L,-,I@,-,,t, These iioia-specitic ca'L@ilvstp, b@@ T-(@f to tl-tro-Lighoiit the I)ron-ioters" and t,ie to 60 h,.ive iio other '- Plie coneet)t oT stabilizer promoters ;s, tli,3,-eTore, iiot i-@, I - teiided to defille tlio indivici-Lials or 0; oups b Lit is relati-%7e aii(i 1-@el'crs to ti-io actioii Ir Of tl-ie catalytic roups iiiider the reactioji @-I conditions obtai.niii(,. TI-ie use o@ the ex1,896,627 p@,essioi-i "s'u-,,,,bilizer proiiioter" shoiilcl i-i-i iio se@,ise be tal@eii 'Lo limit the ijiveiition to t pirticul-,r thoo,@y of IC'uio,-i of these liolisi)ecific cat,,tlys2-S ,incl iii fact in some ca@@es I u stabilizer promoters may be preseiit iihei-c therc,. are lio stabilizers. trcm,.,iici ous riii(ye of cheiitiea l (yroiips 1 - @ @ f , ii-hich may be coiiib-'@iie,'L in or ",ith the leacheci p@- ,P.,iiuto(,@c@iietic boclies pc-rmits a -@vicle elioice of stab;.Iizer promo'Lcrs as ivell 7 qs sp-cific iiicl permits their associatioii Av'ltli the contact masses in ai-i extreiiiely lioino,,eiieo,,--,s aiid catalvtic,-Llly efficiejit f orill. The forniati-oii of the b,.ise excli,@in,e bodies is, of course. ca,,@ric(l oi-i III the ustial ni,,Iil-@ier i) as, l'ol- ex@llli3)le. to ,-be clescrII)tioilg c,,T' ii-iy priir p,,@,tC-Dt ",IICI 11)Pliccltion ,-efoi,red to. The i)reseii4L ii-,-,Tentioll does iio,, depend 1 fo3-- o-;-i aiiv part@ctilar inetlio-,'t of the cxchiii'Yc bo(ly. While, as has been stated above, the presel 111,7CIII@-i(ll aiiiiaionit oxiclatioii ,,I@ i@ wl-i@-,ii CLilii',e(I or 'LiDOipe-riiii,,to-)-eiietic Lodies are use(l, c, zn ilu is iii iiiost to iitilize diItite@L 1,-,ach,-,,! periiii!to-eiietic bo(lies iii the foi@ I u OU@LL tl-ie P,!esellt t@ 'II,-%7 entio@i. ir, ,iltlioii(,Ii ]lot estli.@@ be 1-ioiiio(-eiieoi,,Fly [5 i-iito "iie perm-L,,to--Cnetic 1,,odi-es be-llo.--c of. the latter or @it e a s t b f o r IL I i o I e,-, c'l,, o Ct 1) c,,,@ 1 11 boA,- lias -'@ltily clillients, inei-t, stal)iliziiig. citalyti(.-all,T' ae- i,- t:vc, or siabilizer I)roiiio'L-ei, effec'L-s, ciii be, fey,,7 of the dil.iiejits )vill b,-, base exbo(ii,,,s, nati-ir,,il oi- artificial I)ow(lers of i@ocli:s, trass, 1,,tva. ,).nci sir.,lilarly volegiiie )],Ollt,,cts AA@hich ire fi,2qiici)tly s@ ptilverized sla(' -vtool, S. ptilvei-lzeci tlieninaro,, -'Liillep"s e,,i-eth,'-ale. 5,lass 1)oivdi2r, p,,ii-iiiee iileal, U ,) s b @,,F 'Llog, Ii?ll_,t_ a(,ti,,,ifc,- - ,, , - , , i carbor@., qiinrtz mc-al, vai-io,,iE; iiiiiierils rich in qua,,"Lz. ',)-oAvdei-s qii(i m(@tal -,Iloy po\i,- der,,-,, sqlts of ox-,'iiiet,-,! ,;,cicls s,,ucli ,ts t-Liii-- sta4.-es, iiialliiolyb(lit?F,@ 7 etc., I)artictilar coppe-,--, i,@-,on, sili@@,r or t,io,,@:liiin silts of tlif@ licatc-- ")b,)Ve, si@- a., coppe,,@ s -te, iron sili-cate, cobal'u- altiiiiiI-tLilli sllic,--te, zircoi,,iiim siliC,-tte, niiier,,ils 01- o@,cec@, esi@n;"Illy r;cll j in copper ,in(I iroii, etc. Finely divi(le(I (iii,)re of great espocially wilep tli,@@ Pize ig les@@ th,-Ln 60 ml--roils, ill th,@@ h@,y i ei,,ero, , -wl-iieli lb- II- 5 sor-@-@t;1,7e (-,ii(I a-,Isoupt;v-, c,Lpiciti, of the coita-,It Tii,-is@, the speed ancl - 1)oro@@itv. fiiiclv, (liv@cip-c! diltieiats ii-iL), I)e coiisic'Lerecl @,p, catalysts or - activttors. Dll-uen@lts or'iiiidiliite(-l b,,ise exch,,ti-i,,o _;e bodie-, 70 E,5

.17896,627 3 or their derivatives, siliceous or non-sil;-ceous, may. be finely divided and tised as part or all of the diluents of the letched pei,mutogenetic bodies used in the contacl masses of the present invention. lvhile the iiivention is in i,.o seiase lim;lted to anyparticular method of introducing diluents, they are preferablv iiitroduced by oiie of the nine methods described in coi-inection 10 witli zeolites in my pr@.or Patent No. 1,694,i23 dated Deceniber 4,1928. The' nucleus or non-exchangeable portion of the molecules of tlie leached permutogenetic bodies n-iay be coiisidered t6 contai-.i two types of oxides, nan'le@y, relatively basic metal o-ide@, ustially ampliot,eric, and relitivel3T acidic oxides, stich as SiO, and certain other oxides 6f similar prol)erties which cin replace part or all of the SiO,. The nueleus 20 behtves is a single acid raclical and cannot b-splif ky ordinary chemical m-,ans withotit far reachiing decomdosition btit it is adva,nrtions of the tao,eous to consider the two po nucleus as b,,tsic and acidic portio-.is, bear25 ing iii mind, of c6urse, that the nt,,cle-Lis behaves as a sin(,Ie group. The metal component@ which qre c,@tpable of formi,ig ti,,.e basic portion of the nucletis are s,,tlt or metallates of the followi--ig inetals:-copper, 30 S;.Iver, golo@, bisinutl-i, beryllium, zlnc cadillitim, boro-n, allunairium titrtn;.Vm. .niuni, tin, lead, thorium, niobium, alitiinony, t,,tntalum chromitim molvbdenun-i, tungste-n, uranium, va-tiaditiin, niangaiiese, iron, nickel, t PI pal 3"5 cob,,il , atiniiin, tdiuna. Coii-ipou,-id-s of these elements i-nay e introduced siligly or in mixtures in any esired proporti-oiis, ad-cl pay I be ii-i the fol-I of siniple or conple.-, ions@ It should be uiic,erst'lood thlt soid-e of40 the elements in cei-t,@iiii stayes of oxidati-on may be introdticed either as iiietoilatc-s or iiietal salits. Oti-iers nllty be inti-od-Liced il'i oiily oiie: form, and still others iiiay be iiitrocliieed ir. ,t sta-e oic oxidati6ii 6tlier th,,ziii 45 that desired i'@q the final base exchai-ge body or i-n the fo,,rn of corlplex ceml)6,.i.-i,-Is. AD-iong the complex iono(,ens are ,tiiiiiloiiia, acicl, oxalic ,,cid, fori-iic acid, t-,irtaric acid, C;.tr;.,- acid, gl3reeri-Tie, -,tiid the 50 like. Many of the metals are specific catalvsts T-or the oxidaticn of ammonia, otl-iers ,tre stabilizers ancl still others are stabil-izer profiiioters. The status of an element as catalyst 55 or sta,],-ilizer promoter niay varv w;,th the partici,ilar reaction coT-id4.t;,ons a.@d w;tl-i the nature of the contact mass. Exami)les of conlponents forming the rela4@ . L;ively acid portion of @the le,,tched permutogenetic bod;.es nucil-eiis ire alkaj.i ml eta! siliIcates, wi-iieh are soli-ible in alkali, and alkali r,,ie'u-al salts of acids, slic!h .-,s those of boron, phosph.orti , nitrooeii, 6tc. The exeha.naeabl@e bases of the le,,i,el-ied permutogenetic bodies may, be siibstituted by base exchanp,,e, and tl-ie elemeiits -which can be introduced singiy or in admixtilre by base exchar-ole are the i'ollowing:-copper, Silveri g beryll.i-lim cale-'.um, iiianold aiiimoniiiiii, gaii-ese, zinc, stroiitlulll, eadmii-im, barium, leid, alui-ninlim, titaniiiiii, zirconiui-ii, till, tntiaaon@,T. tlio,-iuin, vana-,!;,tim, thallium, b;lsmuth,'cl@rolilull-lil Liraiiiunl maiiganese, iroii, cc-balt, D-i-cj'-,el, pal'l,,idium, platiitum, and cerium. Tlle exchaia.(@eqble '@,-ases 'i-itroduced M,,ty be specific C,- ,Ltall.-@,sts, tl-.tey @-.i,%y be stabilizers, or they n-i,).y be - tabiiizer proiii-o!"ei@s. 'I'hey m,.ty be introelticed ,zs simi,)I@e ioiis or as coiii-Dlex io-Tis tiid ma.)T eilliaice the catalytic acti@ity of '@-he 4i-Tial c,)D-t,-tet inass, i-r@iprove ilus physical strei-igtli, or both. Leach,-,cl' Ter-@,@a-,@i'ucgenctic bodies i-iia3 T also be - @o,,tted iii the foriil 6f films o,,i inassive ca@r'-erg@,tTl,.iles or iray. b@ ir-ripregnited ther-@in. The massive'cqrriers inay be inert, '@ICtilTatino, oi- tleiiisekves catalysts. @--) iive,-tition i-@iay be carr-Lecl o, t T@--e prc-,sen' i as a singi-- cat,-Llyt-le reE-,ction, n,,tmely, oxidatiop, Of amiiionia to oxides of @.-iitrogeil a,@,iO, where a ptire ai--qmonia sulch as, 'Lor exaiiaple, aramonia cat,alytically synthesized fro,,i t i.ts is used tlils ivill be tl-ie I.Ilo riiiil reac@u-ion. is, ho-v,,-,ever, tr, aclva I ntao-e o--' tho resn,r.'Ll ijiven'u@loii that eree'uive p c ompp site coiitp,,@t masses may be Lisp-cl and -th con impure aiiimonia caii be oxidi7,ed w' co inittnt Fe'-Iec'uive trol.,rsfoimation o-'L impurities ;nto ea,sily s-.p,- ,rab-le or iiiiobjectio-nable products. Tlius, for extmple, aid-monia produced Ps 9, by-prodtic4u T,.6iiLi the diFtillat-'-On of coal ' ivood, ind o-,@ller prodilicts is normally donllaminated v,,itli considerable ainouiits of Oro.D. iii-c ,,Iiiii,,urit,.es or i@.i-ip-Lirities containiilg sulfur, eith(,r -i-oro-,anic such as hvdro-en stilfid, 01, orga-.iie. 'Tt is quite coi-amon f or sucli @'7-1 d -,L)roCl@llCt @IJIMonift jo co-ntain considerable tmo-Lints of pheiiols. -TATI-ie,,i s,,jch an imip -,.IC is P@isseC, oiter a- stiitable 0 41-jic n@,c@ mass con ',II @ly --hed perm,,itogepetic bod t.'t-ie organ'@i2c and otlier iinpuriy ties are oxi Otiz-cl to easily separtible or liarmless prodlicts rnd @it the s,,ii-iie tiliie the a-Tnmo-iiia is ox:cl. iz--d to oxi-cles ol nitrogen. Nil.-Uraillr, of eoiirse , 4-he r --c'Lion rr,,ay or may u e not be absolutely sir@i,,iltaneoti ,tiid lu-11-@ere is 'to believe that ivi-tli composite co,.i'Lact masses a select;--@To oxid--tio,@i o'L imptirities tal.@es place befolze the -.m@- Monia is O-xidized. li'l som,- iiiociIii@tl-,a'c-ioiis ol.' tite 'DrIseiit ip-Nention i'u i-s -,t-]_so desir.@,b',,- I.o arrcing.-- the ca@L,alyst -in 7@ones, -'or extlinple, gases frs-'u t6 encoiil,i,',er tl-ie cio,@itqct i-iiisses which i'avor t"le C4- @i_ile oxiclation of -Elul es tind then I.-o eii-,(--,tlnter a co-utpet mtss i-,hlclal permits ti-@e oi@:leta'u--'-o-i of- ai-timon.i-a to oxides of i-iitrog.-n. Tli.e zo@ies ina-,,T be separated 0-' contiguous. The preseiit invention is iiot concerned with' a, particiiiar temperature a--qd the tem.A

4 1,896,627 perature ran-es "-Iiiel-i have beeii -Lisecl Avitl-i other contact iiiasses aiicl -",hicli normally rtin from 500-800' C. iiiay be employed .tnd the opt-iiiiuiii teiiiperattire ivill of course depe-.id oii the precise n,,tture of +.lie contact iiiass utilized. The proportions of re,,icting incrredie-.,its i-iiay also vary ancl the reaction iiiay be carried oiit a'Ll atmosplieric pressure or at Iressures @ibove or below the atmos1-3 phere. A feav represent,@itive processes comin(y ",,tlii-n the sco,,)e of tli-- I)reseiit i-iivention Avill 'oc set f oi-t.li in gi-eater etet,,til in the folIoNv-lii,ly speel-fic exaii-iples, it beiiicy cleaily 'Lli-iderstoocl tliit the iiivcntioii is not limit-@d thereto. Exa,i7,bple 1 The followii(y tliree sol-LitioDs are - prepared: 1. 24 -)),-trts of SI-0i, in the fori-ii of 330 B6. soditi@,it Nvater(ylass soltition @ire dil,,ited ",ith 64 volliii-ies of w,,),ter. -.Itiiiiinum nitrate is acicl rather tlian alkaline. The conta-l@, ma,ss is leaclied in the, same maniier as described aboire. Examp7c 3 70 (1) 50 pai,ts of freshly precipitated iron oxide -ire prep@ired by acldin- 5-6@'o am11-IODia to a 10-15@/0 ferrolis ilitrate - sollition @,,t 40-500 C. -Lintil the reaction is aminoniacal. The fiiiely clivideOL iron o@,ide is -",ashed - with -43 dislilled ivater to remove the ammonium niiicl clried a@ teiy-iperattires below 100' C. 24 I)arts of lead dioxi-cle in the form of sodii,,iii plumbite are dissolved in ivater to form a 5 @'o solution. 80 (,9)) 5 1),,trts of aluminuin o.-@ide in the form of q freslil.y precipitatecl hydroxide are dis1. Soill@ecL ill a 2 N. potassitim hydroxide soli-ition fo foriii the correspodding potassiuin alui-iii@iate. 85 2. A 5@l,, sodluiii ,tlvmli-tate soliitioii is pre- (4--) IS parts of tliorium nitrate containing p.,,reci froi,-i a corresl)ondiiia aliiiiiiniii-it iii1 9 - i i i o l s o f i v a t e r , i r e d i s s o l v e d i n 1 0 0 p a r t s o f - v v a t e r . trate soltitioi-i contaiiiii-it@ 5 I)arts of Al.(). (5) 2 , , , , i ) a r t s o f c o p p e r n i t r a t e c o i i t a i n i n g 3. r)o p,,irts of f ei-ric iiil-r,@te wlth 9 1- ti o l: ,o f 9 - loy ) IIIO IS of\Yite r are disso lved ii-i 100 parts of 90 lylater are dissolvecl iii ii7ater to form a 0 'water. Sollitiol'i. The f reshly 1)@,,ecil)tated iron oxide is added 50 ,)ai@ts of ,i ii-i;xtiire of rare ezrtlis, mo--Lia- to a iiii-@-ture of the p'lumbite ,tiad aliiminate zite sai,, cl or iiioi-iazite 9,@iTid rof tise are Icldeci s(,I-,it;lo,,is i-il "-liereiipon the tlior,"uiii nitrate to sol-Lition 1. aiid then the aliiminate sol-Lition ,tii (-t coppei, Pitrate sol@,itio.@is, ivhi ch have been 1)5 ispotirediiiNi,-ithvi(-orousa,(-,,-i@atioii. Tothis , i7 togetlier, are ,tddecl. The reaction iiiixtiii-(,, is tlic,,.i aclded siiffici.e-@it fei,ri-c iiitr,,it'e obt,@inecl ig tliorou(ylily pressed and soliitioii so that a sli tn ,gl-it - Ikaliiilt@,7 to PI nol- dr;ecl at 80- 900 C. ancl then brol@en iiito fra(rphthaleiii remain-,, the iciclition to be @ffecteOL i i - i l l i i r s . T h e p r o d - L i e t i s a n o n - s i l i c i o l i s b a s e ivl'tli i,ig@oroiis stil@i-ina. Tlio @-,-'Iati-tioiis p,-eexel ),@.i i-e Lod y co,itain inu alumi DlIM, lead, 100 cll)itq,te ol@'L@,,iiiecl is zeolite contaiiiiii-- a!-Lii-iii-iiiiii aiicl iron @.n non-ex- tl,,oi,iiii,-t and col)per in noi-iexehangeable f o-,@m iiicl iron oxide iii t]- i(, form of ,t diluent. (,Ii.iiigeable forii-i a-ncl rire eartlis eiiiljedcted ,is The prodtic' is leached -with diliite n-iineral (Tiltients. The @);el is separateot from the ,icicl or soiiie-,vli-,t stroiit2:er orgaiiie acid, for llqiioi@ by 'Ls exai-iipl_e lOc7c ,icetic teid, in the maiiner de- 105 Ay,i@@hed Avitli ivqter, dried ,i.t teiiiT)ej-aLlIres scj-ibed iii Eyample 1 vintil p,,Lrt or ,ill of the -pref(,,r,,tb!N, I)elo-N-v 100' C., ,iiid the cake b-,-o- exchin(,eable alkali hts been reiiaoved. l@eii into I)Ieees. A (-Iiliite solittio-i-i o:f 1/@ to 2@,) lvdroel-tioric Ttiei-eiipon the contact ii-ia,@s is ivashecl, driecl, and filled iii".o a coiiverter aiid tl-ie iiiixture of Or siilfiii-ic acicl is ti@ick.ie(l. ov,-r 'LI-ie frq@-meiits of tlie, zeolit'e iititil siil)st,,iiitially qll of tl-ie tiiimo-nj,.i -nci air contiiniiig by volume II( o' aniiiioiia 4-s passed over it at 600-8000 C., exch,iiig,-able. bas beeti The ' - C,- ,)Ocl Y,.@c,,Ids of iii'uro(Ireii o:@icle I)eiii(Y obtained. fra(iiiieiitg a,.,(,, -washeci iv@tli clried n Iii-.td I filled in'Lo ,) coii@,erter, ivlieretipoii a i-o-ix' Tlic, leiel-Led base exchaii(,e body containinii,on oxide iiiay be considereci botl-i as aii adtilre o-f imi-tioni,@t atici qir, 5-15cl, ., iiesiie apcl -,is a st,,tbilizer T)romo4uer whicli 115 of ig i),,i@;sed over the cont-,ct mass it eiiiiaiiees the cat,,ilytic activity of the iron 650-K)OO C., (100(i Yiel(is O'L iiitl,oyell oxid-,s - oxicle. beiii(r oot@iiiied. Otl-ier mo(lified coiit,,,ct masses iiiay be obtained by using cliftereiit componei-it soluIiistead of a tliree-compoiient ze,-,Ii'L-e as (le- tions, for ex,,iml)le the aliiminate and I)Itim- 123 scribed in 1, -, two-coi-tipoiie-,it zeo- bite solutiotis may be par'lv or eiitirely reI.i'Lle ma-,, be I)reT)arecl. b-,, - orr,@spo-.i@,iiiy placed by corresponding ainolints of other -iiiiviti soliitoi -,,imetallates suel-i as, for exainple, chromites. liliioliiit@, of ali,.- ..i i L . stead of ',lie so(li@,im F,,o,iit;- on. Similirly the tiiori-Liiii and copl)er s,,ilt solualu,.i-ii,-iiiii nitm, @Lle solliitic,-,i is iii-@xed tl-@e tions n-ity be p,,irtly or -wholly replaced by -is contaipin- oi-ie or more salts of f,,rric Di-tr,-,te s,) tl)q' op@e i),,irt of sollitioi -,te the ferric nitr, I)rese-,)t foi, etel-i I)art of m,,in(,,-,,inese, zirconium, i-iiekel, cobalt, el-iro,,ilu,l,liiiiii,-i oxide. Tli,,@ oj' Pli Lim, cerium, tit,,tni-Lim or cadmium. tr,ite-altiiiiiiium iiitrate solulion tOde,-! m,,17, Other modified cont,,ict masses m,,iy be obbe sli,-I-itly less thaii in Ey,.aniple I is tli,- teiiiecl by varying the proportions of the 130 kk