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Space and Missile Systems Organization[USAF] ltr dtd 28 Feb 1972

THIS PAGE IS UNCLASSIFIED

AIR FORCE REPORT NO. AEROSPACE REPORT #00.

GAM80T4-421 To-oa~o1-1

Iron Containing Contaminants in N20 4

~ Prepared by H. H. TAKIMOTO, G. C. DENAULT, and P. A. MARSHAerodynamics and Propulsion Research Laboratory

September 1968

Laboratory OperationsAEROSPACE CORPORATION I ''

Prepared for SPACE AND MISSILE SYSTEMS ORGANIZATIONAIR FORCE SYSTEM COMMAND

LOS ANGELES AIR FORCE STATIONILos Angeles, California cy-

THIS DOCUMENT IS SUBJECT TO SPECIAL* EXPORT CONTROLS AND EACH TRANSMITTAL

TO FOREIGN GOVERNMENTS OR FOREIGNNATIONALS MAY BE MADE ONLY WITH PRIORAPPROVAL OP SAMSO(SMT1. THE D1 I -EUTION Ofr THE REPORT I8 UMIfTED ECUSEIT CONT'rN TECHNOLOGY REICTE n..'D MYMUTUAL SECURITY ACTh L5

Air Force Report No. Aerospace Report No.&4m~o-TR-68-I.21 mR-oeoo( 4210-lu) -1

IRON CONTAINnG CORTAMINANTS IN i"2 04

Prepared byH. H. Takimoto, G. C. Denault, and P. A. MarshAerodynamics and Propulsion Research Laboratory

September 1968

Laboratory OperationsAmROSPACE CORPORATION

Prepared for

SPACE AND MISSILE SYSTEMS RGAkIZATIONAIR FORCE SYSTDB CO4WMD

LOS A3ELM AIR FORCE TATIONLos Angeles, California

This document is subject to special export controlsand each transmittal to foreign governiints or foreignnationals may be made only with prior approval ofSAMSO (SWT). The distribution of the report islimited becasue it contains technology restricted bymutual security acts.

4 4

%his repwrt is published by Th Aerospace Corporation, El Segundo,Catlfomia, Air For-A Contract 70o01- -Co2O.

Mai report, vhIoh docmnts research carried out from Augut 1967thronLn Aii 1968, Was xsudt"d on 14 October 1968 to Lieutenant Jobn F.Turk, ]n, e SY , for review -- approvml.

fInf tion in this report is ="roed uider the Deratment of State

Mintrnaticsl Traffic Mm Arm Regulations. Tbis report mny be released toforeign goverots byv deparments Or agencies of the U. 8. Oovrntsubject to approval of Spae Wd Missile SYSteem Orpndsation or higher

mza% riaty within the Deprmmt of the Air Force Private individuals orfir require a Deparmat of State ex]pt liceeee.

Approved

a. W. LigOpemutin General INemr

Pblicatin of this rort does not contitute Air Force aproval of

rthe r tw's findings o noasis. is publisbed onJ1 for the exchange

and tim tion of Ideas.

jo i. Ttrk, 17, 2nd Lt., U

project Oficer

-ii -

The contanenmuts found in N coming flowr bloolaes at the loumch site

lawe been analyzed and Identified as nitrosyl tetrouitratofrate * An authentic

*sW1e of this material wra synthesized In the laboratory for ocaipwson purposes.

The carTSI action of the oxdizer an the Iron conteining materils of con-structions results In the fuzutiom of this contminant.

A6118TPJM o . . . . . . i

no. 33411M . . . . . . . . . . 3

IMI* EUMR6 AND M8Ot38IP .o o . 5

IfiUimU . . . . . . . .... .. .. ..

1. Infrm Spsctaru of Nitrosyl Tetrntratofermte......

Ip

The contaminants present in nitrogen tetroxide can seriously affect theperfomance of bipropellant rocket motors. The deposition of impurities in the

oxidizer can cause decreased N20 flo by partially or completely cloUiginjectors, screens, and filters in the propellant line. One such cotminant

believed to be present in any N 2% that has came'in contact with iron-containing

mterials Is nitrosyl tetranitratoferrate (MWni). Although the presence of this

compond in N2 04 has been shown in the laboratory, its actual Isolation

the oxidizer used In the field has not been previously reported. This report

describes the identification of NM as a mjor constituent in the gel-Like

material that causes blockage of a filter in the transfer line between the

oxidizer transport trailers and the ready storage vessel at Vandenberg AFB.

Si

* II. nCfD 1a=

The stainless steel filter containing the c-ontmiant. asS obtained f

Sic-rI West at Vandenberg Anh. Approximotely 18,000 gal of NI2)4 had been passedthrough this filter, which was located In the transfer Line between the oxidizertransport trailers and the ready storage vessel. The filter and Its contentsbad minimum exposure to moisture during removal and were placed In an air-tightstainless steel container while still copiousliy evolving N02. The containerwas transported to the l.aboratory at Aerospace Corporation and then opened Ina dry box under nitrogen atmosphere.

Etraction of the filter contaminants with ethyl acetate and removal of

the solvent yielded a dark amer-brown viscous material.* The crude contaminants

were purified by the following procedure: (1) dissolution In ethyl acetate,

(2) filtration, (3) remval of the volatile from the filtrate, and (4) Pro-cipitation with fresh N204. This purification process was repeated severaltimes wile excluding moisture to yield a ligbt amber -co:lored solid. The Infra-red spectrum of this conpoxmd (Fig. 1) was taken on a halocazbonmulal between

polyethylene film since YM? reacted with 1a~l when placed directly on thee salt plate and gave extraneous absorptions. Characteristic absorption bands

observed at 225, 1597, 1550, 1280, 1013, 916, and T65 cm- 1 are similar to thatreported for 11W. Further, an authentic s"MU of NMTH was prepared from thereaction of Iron powder and 1 20 in ethyl acetate catalyzed by ferric chloride.This synthetic material yielded an infrared spectrum identical to that for theIron compound obtained from the filter.

In an analysis of i(eNO) ron (Hof.- 5), a kown quantity of 11W wasdissolved In water. Aliquots were taken, and the Iron content of the solutionwas determined colarimstrically using 2-pbsnathrollne as an Indicator on aBecmn Spectrinater EK-2 at 510 ap. The procedure described in AMB IST-58was followed. The values vere obtained by a carpison with a calibration

curm obtained on standard Iron solutions:

Calculated: 16. 8% Fun: 16.8%

-3

IS'

cLAJ

J -

I=

30NVBNiOSBV

IM MOMMaS AND DMBcUMsxE

Addison, at al. (Hof . 1), have described the synthesis of YM by thereaction of 120 with either Iran filitgs, ferric chloride, or iron penta-

carbonyl. Of particular Interest Is the first reaction Involving the mtalliciron that resembles In paut the corrosion process taking place between N204and steel stozege tanks. N204 is reported not to react with metallic ironunleus a catalytic quantity of iron chloride in added. Hmpever, trace smontsof chlorides are known to be present in all proelant grade 1204.. Further,In a synthesis program such as that undertaken by Addison, where a relativelylarge amount of the product was expected, the foration of parts per mllionquantity of MW could be very easily overlooked. In fact Cain, et al. (3sf. 2),have reported that the presence of Iron N20% can be detected a few bows afterthe odiaLer is In contact with the mrtal, powder, stainless statel, or carbonsteel. This reaction is limited by the solubility of YM in the ozidizer, andthe reaction stops when the concentration of the Iron caspounds reaches 1 to 2pAn (detezined an iron).

The reaction product of 124and Iron, Identified by Addison, was later* verified by Cain as nitrosyl tetranitratoferrate (NW) having the following

struture:

This cpoad Is frequently called ferric nitrate N204 "addhct" for sialicity.

The presence of RM even In low concentrations can bring about flow restrictionin the laboratory by conpiete blockage of a tiny orifice by the deposition ofcrystalline or gel-like contaminant (Hsf.- 3). Upon contact with moistume, it isreadily convered to hydrated ferric nitrate, nitric acid, and nitrous acids.

The Iron contmnants In N 2 can take various form, such as straw-coloredsolid, gel, or black oil (3sf. 4),, depending on the purity of the mterli4 anthe water content of the mdia. Althcu* the exact conditions necessary forthe flow restriction process to occur are not camletly understood, two factors

appear to be Inortant, viz., reduction in temperature and the presence of

inall Orifices in the proellnt line. The former causes the separation of

the adduct Out Of solution, and the latter, a location for the accmlation of

the MM. Other factors such A configuration of the orifice, pressure drop,

flow rate, &a turbulence are also believed to influence the deposition of NM.The isolation end Identification of YM from the field in difficult due

to Its extremely bygroecopic nature. Wehi compound is generally convete to

bwdrated ferric nitrMa befre* it can be transferred to the laboratory foranalysis. However, this copond together with other contminnts can be col-lected by passing a large volbin of 12%. through fine filters. *in this study,by taking precautions to minimise exposure to misture, the contents of thefilter were transferred to the laboratory for analyses. M ves Isolated andParifi~dby extraction with dry ethyl acetate and reprecipitation with fresh

%2oh. Te Infrared spectn of this cospyoumd taken on a hslocaz'bon -1ll betweenpolyethlelne film (Fig. 1) showed absorption bends essentiallyv identical to thatreported for MW. Its structure mas further verified by comparison of thespectru of an authentic samile of MUj prepared by the reaction of iron powderwith N12% In ethyl acetate.

Frther substantiation of the NKU structure was carried cut by analysesfor Iron =A nitrite ions after bydrolysis and determination of Its equivalentwaet by titration with a base.* The results aze in aremint with the structure

In additio to NM, other contaminants were also fbxwd to be collected Inthe filter. The residue (app ozmtely 2o% of total contaminant), after extrac-tion with &W-1 aetate, was divided Into a water soluble and insoluble portion.

The foimr was found to be prinarily ferric nitrate nobydrate, which probablyresulted from the hydroljysis of MUI. The water Insoluble fraction consistedof brownish-black magetic imaterial. An x-ray diffraction pattern taken on thismaterial showed this solid to be a mixture of To 3O% and j s

The maJor contamnant trapped In the filter ba been Identified as theferic nitrate N24 "adout. A sufficient qantity of this imaterial am be

collected to result in flow restriction in the propellant Line of the oxidizer

loading unit at the rocket launch alto. This Iron copound results froa the

reaction of N0with the iron containing material of construction. Since the

oxdizer is inuatured In stainless steel apparatus and transported and stored

In either stainless or abon steel equipment, It appears that all N20 (unless

specially parifled) will contain iMW. Further, if the oxidizer had undergone

considerable fluctuation in tempaxsture over an extended period of ttm,, it mycontain a much higher quantity of MIO than realized fran the solubility data.

Vader these conditions, it can exist as a separate phase in the oxidizer in the

fa of a solid, gel, or an oil.

The oxides of Iran are believed to result fra the action of wet 204 with

can steel. Indications are available which show that when the water content

of the oxidizer Is high (such as Incomlete drying of transport trailers after

hydrostatic testing) a larger quantity of Iron oxides is observed in the oxi-

diver.An aqueous solution of NOY in water was analyzed for nitrite ion (Ref. 6)

by a coloelastric method using sulftnilie acid and e-naphtylafine (Griess

reaent). The rric ion which Interferes with this analysis was camplezed

with the addition of 1% HP solution. Coarison of the absorption to a standard

curve yielded the value for nitrite content.

Calculated: 13.8% Fu:3.9%

In the determination of equivalent weight, a solution of I'M can be titratedwith base to a pH endpoint of 5.7 according to the following equation:

Ncft(NO3 )4 + 5 on - fte(Off) 3 + 4I 303 + N0; + 12

Equivalent w igtht of the iron-containing acmpound from the filter can be calcu-

lated by the above equation.

Calculated: 67.80 Found: 67.3%

-7-

"T"

%" IK

1. C. C. Addison, P. 14. Dooiua4 and N. Tomn, "haducts of iron (ni) itawates

with Oxde of Nitrogen," J. Cm. Soc. 11978 (1965).2. Z. 3'. C. Cain, ot &I., Methods for MflIiation of CorroIan Products of

w -age Totrowdde, Fia Report AIRPL-T-6T-2TT, nocketdyne Division ofNorth American Aviation, Inc.*, Canoga Park, Calif. (July 196T).

3.* B. J. Salvinaki, Investigation of the Fomtion and Debavior of Clogging

IOterIal In art and Spame Storable Propellents, Interim Report (38133-

6007-300, TRW Sstem Group, Redoudo Reach, Calif.- (October 1967).-II. G. C. Demult, F. D. Hoe, L. Schieler, and ff. H. Takinoto, AnaLyses of

Nitromz Ttd.CnnasCllected on screens and Filters Toa-oO

(3116-35)-i, Aerospace Corp. (December 196T).

5. AMD tadards Ceical Analysis of NetalU; Somling and Analysis of Neta

Dearing Ovs, Part 32 (May W965).XtieAnlIs6. 0. Charlot and D. Dozier, Quantitative Inorganic AnaLyis.1 translated from

tVm 3rd. French ed. (1955), Jobm WileY and Sows 3hc., New York (1957),.

p. 522.

-9-

UlCIASSIFIEDSecurity Classification

IRQOCUEN CONTROLu DATAIIM' -R&

I OURIPAINATIV I T (y pe, athor 20.aIv REOTaM.)YC ASIIAT

S AUTHOR(S) (Lost nam~e. fint nm. initial)

Takimato, Hideyo H., Densult Genevieve C.*, and 1Mrsh, Peter A.

G* REPORT DATE 70. TOTALNo. or PAGES 7b. No. all RaeS

September i9q68 Ul 6So. CONTRACT OR GRANT NO. SO. ORIGINATOR'$ REPORT NUMDER(S)

FO'IO1-8-c -om -o( 1 20l)-61 PROJECT No.TOM 20-)l

is. ~T4:JPORT NO(S) (Any other, numb.,e tat m~ay be assido

d, SAM~O-T-68-Il210, AV VA IL ASILITY/LWMITATIOW NOTICIRS

This documnt In subject to special export controls and each transmittal toforeign goernts or foreign nationals my be mde only with prior apprvalof SAMUO (SIM'). The distribution of the report is (continued on reverse side)

11. SUPPLEMENTARY NOTES 1. 4IISORINO MILITARY ACTIVITYSpace and Missile System OrganizationAir Forces System CinmaLos Angeles, California

13 AESTRACT

5The contamnants found In I(-,'r' causing flov blockage at theImohe site hae been =nlye and Identified as nitrosyl

tetrmnitratoftrrate * An authentic s=le of this uterialwas synthesimed, In the laboratory for comarison purposes.The corrosive action of the o~ddizer on the iron containingintsrial of constructions results :in the fozuation of thiscontaminants 1,

00 FORM 14n -LCAB~nPA CSIILEP

Security Classification

Socutity Classiicatiwa14. KEY WORDOS

mitloyal Tatzesnitaatoferrate

Ferric Nitrate

K ?@Ztlc Nitrate *1N04 Adiuct,

NA Costeinant

10. (coixtrnued)

limited because it contains toohnoloUr restricted by mntual security sets.

Socurity Clagificatia