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The heterogeneous decomposition of nitric oxide on supported catalysts
Atmospheric Environment Pergamon Press 1969. Vol. 3, p. 493. Printed in Great Britain.
THE HETER~~ENEOUS DECOMPOSITION OF NITRIC OXIDE ON SUPPORTED CATALYSTS* THE MANUSCRIPT relates to the study of the decomposition of NO over metal oxide catalysts. The results are in qualitative agreement with other published reports on the subject, with one important exception: Shekf, Otto, and Gandhi conclude that the decomposition of NO is a tirst order reaction w&mart the earlier resuits of Yur’eva (reviewed in the paper) indicated the decomposition reaction to be of second order. The nrpaimcntal approach in the two studks are sliBhtiy different: Yur’eva employed pure NO whereas authors of this paper have employed mixtures of NO and He for the &ermination of the reaction order, It would be helpful if the authors included a mention of the concentration range of NO-He employed by them. The calculations described on page 120 under ‘Estimation of converter employing the decomposition of NO’ are unwarranted. The problem of the decomposition of the NO present in automobile cxha~ts (ot 8tack gases) is radically different from the decomposition of pure NO or NO-He mixtures in vkw of the other gascapresent in automobik exhausts (or stack gases). Previous inve&atom have reported ditBculty in am&ring mixhues of oxides of nitrogen by mass SPCC!RXW~IY, p8rtiably mixcontaining NOa, (F~U.XDEL et 41. (1953). Was a special “conditioning” technique used? Were synthetic blends am&red? United Status Dept. of the Inter&r, Bureau of Mines, 48CWF&s Ave., Pittsbuqqh, Pent&m&, 15213. U.S.A. REFERENCE Frurroat. R. A., !IA. 0.. Jr, SHULTZJ. Land H~JM~ERT C. R. (1953) Mass spectometric analysis of mixtures containing nitrogen dioxide. Art&t. Chem. 2!t, 1314-13#3. l
Am&tic
Envlionment (1%9) 3 (2). X07-122.
AUTHOR'S REPLY F~QURB 3 @es directly the NO concentrationa employed, which were between 5 and 100 per cent NO. The point of the c&x&ion on p. 120 is preckely to demonstrate that the dcconrpariHon of NO to ekmeatsisrlowandimpracticablt.TheotherOesestowhichMr.~~refusmny,ifpresmtinthe exhaust in aufBcknt amounts, r&ice the nitric oxide. We would like to take this opportunity to dkcourep the often encountered hunpinq of the decomp&tion and reduction of NO under one term. There wu a nurkcd di!Tcrcnce bctwacn our mw-spwtron~~I~ andysaz and those of Frkdel et ul. Wehvaemploytda~~~~caplllprykakinstrumtntwhich~at~p~cpreasuraand monitarsa~~channinr~katapressunottheotduof1torr~~theOoidlePk.~ instrumentofFrkdelwaaab8t&-typeopmatingatlow pmmurea (-100~). Even Friedal lma obtaipod good 8tability after upedal “conditioning” with NOa to remove by reaction carbon and polymsrizea hy&oarbone. ‘Ibe amount of tkee contaminants with compa&m to the large amounts ofNOI ooino c~ntimnmsly through our &trument can be considered as negligibk and did not cause instabilitkaintheN0,peak.Tbe corm&Kmoftheanaly!dswasalsoborneoutbythematerial bakmxs. M. SHEZEP Fwl Scfeneee Dept., Ford Motor CompMv, P.O. Box 2os3, Dearborn, M&h&an 48121. U.S.A. 493
THE HETER~~ENEOUS DECOMPOSITION OF NITRIC OXIDE ON SUPPORTED CATALYSTS* THE MANUSCRIPT relates to the study of the decomposition of NO over metal oxide catalysts. The results are in qualitative agreement with other published reports on the subject, with one important exception: Shekf, Otto, and Gandhi conclude that the decomposition of NO is a tirst order reaction w&mart the earlier resuits of Yur’eva (reviewed in the paper) indicated the decomposition reaction to be of second order. The nrpaimcntal approach in the two studks are sliBhtiy different: Yur’eva employed pure NO whereas authors of this paper have employed mixtures of NO and He for the &ermination of the reaction order, It would be helpful if the authors included a mention of the concentration range of NO-He employed by them. The calculations described on page 120 under ‘Estimation of converter employing the decomposition of NO’ are unwarranted. The problem of the decomposition of the NO present in automobile cxha~ts (ot 8tack gases) is radically different from the decomposition of pure NO or NO-He mixtures in vkw of the other gascapresent in automobik exhausts (or stack gases). Previous inve&atom have reported ditBculty in am&ring mixhues of oxides of nitrogen by mass SPCC!RXW~IY, p8rtiably mixcontaining NOa, (F~U.XDEL et 41. (1953). Was a special “conditioning” technique used? Were synthetic blends am&red? United Status Dept. of the Inter&r, Bureau of Mines, 48CWF&s Ave., Pittsbuqqh, Pent&m&, 15213. U.S.A. REFERENCE Frurroat. R. A., !IA. 0.. Jr, SHULTZJ. Land H~JM~ERT C. R. (1953) Mass spectometric analysis of mixtures containing nitrogen dioxide. Art&t. Chem. 2!t, 1314-13#3. l
Am&tic
Envlionment (1%9) 3 (2). X07-122.
AUTHOR'S REPLY F~QURB 3 @es directly the NO concentrationa employed, which were between 5 and 100 per cent NO. The point of the c&x&ion on p. 120 is preckely to demonstrate that the dcconrpariHon of NO to ekmeatsisrlowandimpracticablt.TheotherOesestowhichMr.~~refusmny,ifpresmtinthe exhaust in aufBcknt amounts, r&ice the nitric oxide. We would like to take this opportunity to dkcourep the often encountered hunpinq of the decomp&tion and reduction of NO under one term. There wu a nurkcd di!Tcrcnce bctwacn our mw-spwtron~~I~ andysaz and those of Frkdel et ul. Wehvaemploytda~~~~caplllprykakinstrumtntwhich~at~p~cpreasuraand monitarsa~~channinr~katapressunottheotduof1torr~~theOoidlePk.~ instrumentofFrkdelwaaab8t&-typeopmatingatlow pmmurea (-100~). Even Friedal lma obtaipod good 8tability after upedal “conditioning” with NOa to remove by reaction carbon and polymsrizea hy&oarbone. ‘Ibe amount of tkee contaminants with compa&m to the large amounts ofNOI ooino c~ntimnmsly through our &trument can be considered as negligibk and did not cause instabilitkaintheN0,peak.Tbe corm&Kmoftheanaly!dswasalsoborneoutbythematerial bakmxs. M. SHEZEP Fwl Scfeneee Dept., Ford Motor CompMv, P.O. Box 2os3, Dearborn, M&h&an 48121. U.S.A. 493