UNCLASSIFIED

AD NUMBERAD525359

CLASSIFICATION CHANGES

TO: unclassified

FROM: confidential

LIMITATION CHANGES

TO:

Approved for public release, distributionunlimited

FROM:

Controlling DoD Organization. EdgewoodArsenal, Aberdeen Proving Ground, MD21010.

AUTHORITYTD, ECBC [AMSRD-ECB-CB-CR], DA Form 1575,11 Jul 2006; TD, ECBC [AMSRD-ECB-CB-CR],DA Form 1575, 11 Jul 2006

THIS PAGE IS UNCLASSIFIED

-- • AD- 52535P

_- • SECURITY REMARKING PEo•UIREMENTS

DOD 520(ji-R, OEC 78

= • REVIEW ON 28 MAR 93

1p

t9

I9

I9

- 9

Ii

SECURITYMARKING

The classified or limited status of this repodl applies

to each page, unless otherwise marked.

Separate page printouts MUST be marked accordingiy.

THIS DOCUMENT CONTAINS INFORMATION AFFECTING THE NATIONAL DEFENSE OFSTHE UNITED STATES WITHIN THE MEANJNG OF THE E•P1ONAGE LAWS, TITLE 18,

U.S.C., SECTIONS 793 AND 794. THE TRANSMISSION OR THE REVELATION OFITS CONTENTS IN ANY M, ANNER TO AN UNAUTHORIZED PERSON IS PROHIBITED BYLAW.

NOTICE: When government or other drawings, specifications or otherdata arc used for any, purpose other than in connection with a defi.-nitely related government procurement operation, the U. S. Governmentthereby incurs no responsibility, nor any obligation whatsoever; andthe fact that the Government may have formulated, furnished, or in anyway supplied the said drawings, Epecifications, or other data is notto be rcgarded by implication or otherwise as in any manner licensingthe holder or any other ptrson or corporation, or conveying any rightsor permission to manufacture, use or sell any patented invention thatmay in any way be related thereto,

CONFIDENTIAL

[ADz

EDGEWOOD ARSENALTECHNICAL REPORT

EATR 4710

VAPOR PRESSURE MEASUREMENTS OF

SOME CHEMICAL AGENTSk' USING DIFFERENTIAL THERMAL ANALYSIS

PART 1. (U)

by

Frederic Belkin

Harry A. Brown, Jr.f Chemical Laboratory

March 1973

{ DEPARTMENT OF THE ARMYHeadquarters, Edlewood Arseni

Aberdeen Proving Ground, Mayland 21010

CWthesd by AR 311046EExempt from GDS of EO 11652

E xontocwt CafsgVwy 3DoediWfv on: tC# conroot be ptedetetmrnd

CONFIDENTIAL

Disclaimer

Dhe findings in this report are not to be construed as an official Department of theArmy posiors unless so designated by other authorized documents.

The use of trade names in this report does not constitute an official endorsement orapproval of the use of such commercial hardware or software. This report may not be cited forpurposes of advertisement.

Dispo sit ion

When this report is no longer needed. Department of the Army organizations will"-lestroy it as prescribed by AR 380-5. Navy and Air Force elements will destroy it in accordance

with applicable directions. Department of Defene contractors will destroy the report as prescribedby paragraph 19 of the Industrial Security Manual for Safeguarding Clamsified Information. Allother recipients will return the report to ('ommantIdcr. Fdge%%ood Arsenal, Attn: SMU|FA-A(;-ClasDocu. Aberdeen Proving (;round, Maryland 21010.

CONFIDENTIAL

EDGEWOOD ARSENAL TECHNICAL REPORT

EATR 4710

VAPOR PRESSURE MEASUREMENTS OF SOME CHEMICAL AGENTS

USING DIFFERENTIAL THERMAL ANALYSIS. Part I (U)

by

Frederic BelkinHarry A. Brown, Jr.

Chemical Research DivisionChemical Laboratory

March 1973

Projict 1TO16 IO1AQ)IA

DEPARTMU NT 0IF THi1 ARMYlicatqcttarters. Fdgcv, ood Arwn•i

Aterdeen P'omin. Ground. MarYLand 1O!O

(lamfied by AR 11,-,.V-. ietu!! froin W;S of 1:0 116 5:

,_- CONFIDENTIAL,..- t~t " •..,. +,

"\4-,*'

UNCLASSIFIED

(U) FoR__woRI_

The work described in this report was authorized under Project I T061 10 1 A9 I A.In-House Laboratory Independent Research Program (U). This work was started in February 1970and completed in May 197 1, The experimental data are recorded in notebooks 8343 and 8337.

Reproduction of this document in whole or in part is prohibited except withpermission of the Commander, Edgewood Arsenal, Attn: SMUFA-TS-R, Aberdeen Proving Ground.Maryland 21010: however, DDC is authorized to reproduce the document for United StatesGovernment purposes.

Acknowledgment

The authors wish to acknowledge the technical assistance of the personnel oi theChemical Research Division, Analytical fi-emitr\ Branch. who performed the analyses.

UNCLASSIFIED

\

UNCLASSIFIED

(U) DIGEST

A method for determining vapor pressure-temperature relations for chemical agents ha.;been developed using a modified differential thermal analysis (DTA) apparatus. Vapor pressure datafor 10 compounds have been generated. These compounds are: GF, VX, EA 1356, EA 2222, EA

2223, EA 4923, EA 5365, EA 5403, EA 5414, and EA 5488. A computer program was used toreduce the eyperimental data and fit it to the Antoine vapor pressure equation. In addition,volatility and heat of vaporization were calculated for each compound over selected temperatureranges.

The DTA metho'4 permits vapor pressure measurements to be i-Lade of relativelyunstable compounds at higher temperatures thaii can be made with the Knudsen cell or theisoteniscope. Significantly smaller amounts of materi.i are required for the DTA method. Thetechnique ;s presently useatle at pressures between approximately 1 and 760 tort, at temperaturesabove 35* to 40* C.

I

UNCLASSIFIED

.............................................. ...,,++.•••••--

UNCLASSIFIED

1. INTROD)UCTION .. . . . . . . . . . . . . . . . .7

It. APIPARA T1 S . . . . . . . . . . . . . . . . . . . . . . . . . . 7

III. PIRO'I:I)URI:S. .. .......... ......... . ........ ................ 8

A. Ex.p.r...................... . . ..... .. .. .........13. (.dcukd ion's...................................... . .. ... . . .. .. .. ........

IV. RESULTS. .. ................... .................... ...... 12

A~. \todcd mtim Ih............... .. .. .. ............. 2h. Sample Anari-I".'.................... . .. .. .. .. . . .. ..C. \apor 1'rc'sturtr )-lta... .. ............ ... . . .. . .. .. . . .. ..

V. D)ISC'USSION.............. ........................... 14

VI. ('ONULUSION\S . ...........

LUTIRMU.RI' ('111) . ...... .................. .. .. .. .. .... 1

GLO( SSARY . . . .... .. ....

PINtI)UIO\ LIST q

I, 1% 01 1AMU 1

1,. (licnis~a Piitl of~ .h4-nhJ t Saml i.k ' -'% 'tt~IA~'

II. Ag i V- ot Pr;wkot,. Mit la tiwtolIt.z 1,;

UNCLASSIFIED

CONFIDENTIAL

(C) VAPOR PRESSURE MI.ASUREMENTS OF SOME CHEMICAL AGENTSUSING I)IIFI.RENTIAL THERMAL ANALYSIS

1. (U) INTRODUCTION.

The measurement ot vapor pressures of some chemical agents has been, in the past,limited to relatively low temperatures with respect to their normal boiling points, since many ofthese compounds are thermally unstable and will decompose more rapidly at elevated temperatures.The methods presently in use in our laboratory. such as the isoteniscope and the Knudsen celltechniques. compotund the proilenis because they require that the material remain at constanttemperature for times ranging from several minutes to several hours. These isothermal methodscannot. therefore, be used at temperatures where appreciable decomposition of the compound mayoccur.

A method of vapor pressure measurement was sought which would have advantagesover the standard methods. Desirable features would include: (1) elimination of the necessity to"subject the compound under study to high temperatures for extended periods: (2) rapid acquisitionof data: f3) small sample requirements for each experimental determination: (4) also, it would beavailable commercially. requiring only minimal modification to provide adequate performance.

There are several reports which describe the use of differential thermal analysis (DTA)methods for the determination of boiling points of pure organic liquids] and for the determinationof vapor pressures.2 4 The initial experiments presented here with model compounds showed thatDTA methods could be succcssftully used for measuring the vapor pressures of a variety of chemicalagents at temperatures where the isothermal methods could not be used.

11. (U) APPARATUS.

The apparatus used for the experimental determinations was a modified version of' theCalorimeter Cell.* Modifications introduced included: (1) substitution of a standard DTA block forthe Boersma-type air cell. (2) rewiring of electrical connections to obtain negative 'y' axis deflectionfor endothennic reactions. (3) attachment of flow and pressure controls to the base of the cell, and(4) a modified version of the bell jar to allow measurement of cell pressure close to the samplelocation.

Ancillary equipment included two types of vacuum systems. For pressures between 15and 760 torr. a vacuum pump was connected to the system through a manostat. a 25-liter ballasttank, and a cold trap filled with dry-ice-acetone mixture. The system pressure is controlled by the

I Vasulo. D.A.. and Iiarden. J.C. Preciw Phase Transition Mleaurements of Organic Materials by Differential Thermal Analysis.Anal. Chem. L4.132 (1962).

2 Krawetz. A.A.. and Tovro,-.. r. I)etermlnatlio ot Vapor I're-,rt, 1h) Differential Thermal Analytis. Rev. Scl. Inotrum. U. 1465(1962).

3 Barra,,. E.%I.. Pkorler. I.S.. -and Jihm'on. J. %licroboiling Point D)etermination at 30 to 761) Torr by Differential ThermalAnalki. Anal. Chem. 17. 11153 119651.4 mKenme. II.R.. and Krep. S.I. Vapor 1're%%ur I)0t0rnMnathii Ilk Differential Thermal Analyi%. Anal. Chem. 41, 1969 (1969).

* Manufactured 1,y F.I. dPlont tic Nemour% & Co.

CONFIDENTIAL7 MECEDTM *PAGE BLUNE.NO' F•UI4ED

UNCLASSIFIED

manostat and measured by a precision mercurial manometer connected to the system through aport in the bell jar. A diagram of this system is shown in figure 1. For pressures below 1 5 torr. themanostat, the ballast tank, and the manometer were removed from the system. Pressure in the cellwas regulated by using an adjustable continuous-leak valve attached to the cell base. Cell pressurewas measured with a size "D" McLeod gauge (pressure range 0 to 15 torr) mounted directly on thebell jar.

The cell was connected to a Model 900 DTA apparatus.* This unit provided

temperature control of the pressure cell and a means of recording the experimental data.

1ll. (U) PROCEDURES.

A. (U) Experimentation.

Experimental precedures were very similar to those used for normal operation of theDTA apparatus except for control and measurement of cell pressure. Between 1-and 5-microlitersof the liquid sample was placed on 100 to 140 mesh glass beads contained in either a standard 2-mmsample tube or a 4-mm-diameter by 28-mm-long sample tube. The tube was generally filled to adepth of 2 mm with glass beads. The reference sample consisted of a similar amount of glass beads.The reference and the sample tubes were placed in the DTA heating block, the sensingthermocouples were inserted into the tubes, and the bell jar was put in place. After the vacuumpump was started and the desired pressure was established in the cell, the run was started. Linearheating rates of between 10* and 20* C/min were generally used.

The thermogram obtained for each experimental run exhibited an endothermic peak atthe temperature where the sample boiled at the experimentally fixed pressure. The boiling pointtemperature was determined by extrapolation of the foreslope of the peak back to the baseline. 5

For each run, the boiling point could be determined to an accuracy of ±0.5"C. Figure 2 showstypical thermograms for pure and impure compounds.

Vapor pressures below 15 torr were measured with a '"D" scale McLeod gauge accurateto ±3%. Higher pressures were measured in initial experiments using a Wallace & Tiernan Model FA135 manometer, accurate to ±0.25 torr. This manometer was subsequently replaced with a Wallace& Tiernan Model FA 187 manometer, accurate to ±0.15 torr. The Model FA 187 manometer wasused in vapor pressure measurements of agents EA 2222, EA 4923, EA 5403, and EA 5488.

B. (U) Calculations.

Using a computer program and plotting techniques developed by Penski and Latour, 6

the experimental data obtained for each compound were fitted to the Antoine vapor pressureequation

Manufactured by E. 1. duPont de Nemours & Co.5 Smothers, W. J., and Chiang, Y. Differential Thermal Analysis: Theory and Practice. p 45. Chemical Publishing Co., Inc., New

York, New York. 1958.6 Penski, E. C., and Latour. L.J. EATR 4491. Conversational Computation Method for Fitting the Antoine Equation to Vapor

Pressure-Temperature Data. February 1971. UNCLASSIFIED Report.

UNCLASSIFIED

8

UNCLASSIFIED

I -P.

JI- -D

l - l

UNCLASSIFIED

\9

P 5 \:

UNCLASSIFIED

/B. P

fB.R

10

(b)

TEMPERATURE ,, -

2"gr (C ( t-"} Tp,•=i l~ Fndothcrtmi

(a) Pwu• C•ompound. (hi Impu~rc onipound

UNCLASSIFIED

UNCLASSIFIED

log P A - B/(C + t) (I)

where

P = vapor pressure in tortt temperature in degrees centigrade

A. B. C constants

The Antoine equation has advantages over other vapor pressure-temperature equationsbecause of the small number of constants required, and the extrapolations are believed tr be morereliable than for other equations.?.

From the vapor pressure data, other physicochemical values can bc calculated. Thecomputer was programmed to calculate the heat of vaporization (Kc.a!tnole) and the volatility(gm/cu m) for each compound from the following equations

14.57(,h × I03¾BT2

heat of Vaporization = X -3)B21C + t)+

lPs 10 3volatility . .. ... ... __3

0.082053T

where

B and -C = alnc conttants

It a tenp-•ratur in dc-riee vntgipde

T tempcreatur- w &pcc• )Kehlin

P = apor pfe',ur in aro tt

4 s mokcu.at u't-

7 %ad.R $t zdSrv4 I TB toU T ~(.sm tl s; i.,' p I *Act;- 4W %f' 00 %.4- --4k st

Tumawft. W The AR~ouW I rp~am f"t v4ms* Oata c~u-f. *r% 1%. i 1

UNCLASSIFIED

IJ

UNCLASSIFIED

Substitution into the Antoine formula permits the vapor pressure to be calculated atany desired temperature. The standard deviation (SD) was calculated for each Antoine equationusing the following equation:

SD ( 2 (4)

where

S = E(log Pcalc - log Pexp)

Using the logarithmic values prevents excess weighting of the higher values.6

IV. (C) RESULTS.

A. (U) Model Compound.

Aniline was used as a model compound to aid in the development of the DTA methodfor determining vapor pressure. Stull's data 9 were used to develop an Antoine equation for thiscompound.

log P = 6.5605 - 1264.69/(158.03 + 0

The vapor pressure of Reagent Grade, A.C.S. aniline was experimentally determined at temperaturesbetween 44°C and its normal boiling point. 'hit calculated vapor pressures obtained from theAntoine equation for the literature values were correlated with experimental values. The maximumerror between these results was about 5%. which is the expected maximum error for the Antoineequatioo."1

B. (U) Sample Analysis.

Chemical purities of the compounds used in this study were determined by peIronnelof the Analytical Chemistry Branch. The results of the analyses are presented in tables I and 11. Thestructures iind nomenclature for these compounds are presented in the Glossary.

C. (C) Va-or Pressure Data.

(U) The vapor pressure of two samples of FA 2223 having different purities were nieasuredand compared. Since comparable data were obtained with the two samples ol tUA 2223. the datawere combined and treated as one data set.

9 Stull, D. R. Vapor Pressure of Pure Substances. Ind. and Eng. Chem. 9,. 517 (1•141.

UNCLASSIFIED

12

UNCLASSIFIED

Table I (U). Chem'cal Purity of Agent Sari-ples

WCompound Purity Method of analysis

VX 91.9% Hydrolytic

G F 84.4% Hydrolytic44 mg H+/ 100gm

EA 1356 85.6% Hydrolytic1 mg,4+7l100gm

EA 22221 90-617 Thiono content

91.47( Hydrolytic

One peak Gas chromatography

EA 2223 8 87.6% HydrolyticSample 1 2 mg H+/100 gm

EA 2223 94.0'; HydrolyticSample 2 <1 mg H+/ 100 gm

EA 5365 88% Base hydrolysis

98% Acid hydrolysis

EA 5403 95.5%If Total amine

jSet' table I I Elemental analysis

EA 5414 See table 11 Elemental analysis

EA 5488 98% Titrimetric()5% HydrolyticTrace impurity Gas chromatography

EA 4923 84.9%rt (wý chromatography4.71% EA 21.5% Unknown

8.11% Not clutcd

UNCLASSIFIED

A CONFIDENTIAL

Table 11 (C). Elemental Analysis of EA 5403, FA 5414. and EA 5488 (U)

EA 5403 EA5414 EA5488E le m en t .. . .. .... .. .... ..... ..

Calculated Found Calculated Found Calculated Found

C 30,6 40.1 39.6 30.9 45.8 45.8

1H 8.6 8.7 8.6 8.8 7.7 8.0

F 8.95 8.35 8.95 8.51 8.04 *

N 13.2 12.1 13.2 12.9 11.9 11.8

0 15.08 * 15.08 130.45

P 14.60 14.13 14.6 14.5 13.11 13.06

* Not determined.

tU) Table III provides a compilation of the constants for the Antoine equations for thechemical agents studied. Table III also provides the experimental range over which the data wereobtained, as well as the boiling point as calculated from the Antoine equation for each agent. The

standard deviation of th- experimental data from the Antoine equation, which was calculated usingequation (4), is also presented in table III. Thc appendix provides line plots constructed from theAntoine equation. Volatilities and heats o•f p,''irtion were calculated using equations (2) and (3).these values are provided at selected temp.,.' in tablc IV.(U) The calculated value brt (" in thc Antoine equation is often found to be less than 273.

"The dependence of C on the experimental data points is rather scnsitive; and if there are deviationsin the data or if the data range is too narrow, a value of C( may be calculated which is not realistic(it . less than 100 or over 300). Therefore. if C was found to be out.ide this range, the value 273.15was used. This converts the Antoine equation to the C(laumus-Clapeyron equation.

V IU). DISCUSSION.

The method of vapor pressure ineasuretnent desctribd in this report has severalimportant advantages over the standard metho•s. It is a dynmmic method which doer not subjectthe material to high temperatures for extended penriod The viet hod is relatively rapid. requiringonly small amounts of material for each experimuntal dtetermina.tion. An apparatus is availabk onthe commercial market which requires only minor nuodifcataion• to 1e used for thesedetc-rmnations. These modifications. hovever. do not preclnde u&C of the instrinment fof itsprinau,, purpose --differential thermal analysis.

CONFIDENTIAL14

UNCLASSIFIED

Teble V provides a comparison of the normal operating parameters for the DTAmethod with those of the isoteniscope 10 and the Knudsen 1 methods. It should be noted that thecoiparisons made are general in nature and that any of the methods may be useable, under certaincircomstances, outside of the listed ranges.

Comparing the vapor pressure determinations performed by Lafferty 12 (from 600 to

140C() on EA 2223 with this work, there is a maximum difference of less than 6% between the

calculated vapor pressures of the two determinations. In another vapor pressure study, by Link. 1the maximum difference between the overlapping curves (from 600 to 900C) was about M,.L-fc.-'y's s. np!-z ha'1 a parity of 91.3% and that of Link, 84%.

Table III (U). Agent Vapor Pressure Data

Agn Antine ,-inst,...ts Experimental Boiling Standard deviationAgenA B C ..... range point* 10-2

°C °C log (torr)

GF 6.5679 1516.31 171.81 55-17C 239.4 4.11

VX 3.7840 3E47.39 273.15** 110-235 293.9 2.52

EA 1356 6.3580 1384.13 157.34 (.0-2.5 240.7 4.58

EA 2222 7.1814 1482.28 222.64 40-120 122.0 3.00_ 60-2 _. 226.6 2..17EA 2223 7.9819 2485.60 2t'O.70 6-" 266.1EA 4923 7.7754 .030.91 241.67 ,--75 '31..3 1.12

EA 5365 8.8125 2877.64 26C.38 60-150 22'.8 2.61EA 540.3 8.8879 2947.07 269.72 60-150 220., 2.48

EA 5414 9.7060 3320.35 .)o2.36 00-155 2 N.1 2.30FA 5488 8.4629 3226.38 1,S."1i 30-215 304.8 .09

The tcnmperature calculated frnm th, Antoine e;juatton at P = 760 torr.

C ( is taken as 273.1l 50 .

I OSmnith. A.. snd Micnti. A.W.C. Sudi•cs mn Vapor Pte III. A Static Meihtkid ft kctrmirn$nn the VpaclP=um ofSohds nd .quids. J, Am. Chem. Soc j. 0t4 91 :O1.

.homon. C. W. Physi4cal UttIds t, (.) (luhmtwtry,. Part I. A. -Weisse. ha- p 14)1 In etcnm Publaxhrti.

New York. Ne4w York. 1949.

WLjerty. J.P. Notebook 6955. pp 6.8, Febtuuy 1963, CONFID'N"IAL Not-(.E,# .

WLink. R. Notebo* 63". p 42. Auzs, MO60. -OF3DItNTIAL tthbOk.

UNCLASSIFIED

CONFIDENTIAL

Table IV (C). Calculated PhysicocihemiLal Propcrti•% of Sone (hchmiacI Agents (U)

Agent Temperature Previtre Volaitility licat of vaporization

'C torr gm/cu mI KcaI/mrole

GF 250 0.07-3 0-71 15.t2Iso* 0.*4 4.82 14.73

100 9.76 75.55 13.08150 71.80 490.1') 12.00)

200 308.84 1885.7 11.24

VX 1000 0.65 7.48 15.32150 7 47 75.7 15.32200 51.20 4n,4.0 15.32250' 242.41 I490.8 15.32

FA 1.356 50* 0.48 4 14 15..,1003 0 54 1.58 1 32150 7-5, ,2, 3 Mt))

200 i.ti 12 2100114 I Il

IA 2222 25" IS •," l0 1,8 "50 55.53 I5,_ , 5

100 kx(..43 I 2c, 3 " t

FA 2223 50° 10,, ,• "4 I 10

100 8 .O -. ,- I2 1'

IS0O .3)601 t I2011

I'A 4W2.1 50( 141) tO t5 II at100 t. |.o 0 II 08I

150 3014 19401 4.08

I-,A 5.10 50 0 If 1 42 14''1to0 '2 5, 14 12ISO 0-. 15 4'4 1 14tll

*A 40 0 4'" 4 01, 1.100 i Ii -5 -I '1

ISO .*144 It 0

4'A W414 s0" 0:,10t oo 49 11 ) , I,, t lISO AS u, 4 , 0.

100* 0 fý 6 14~ISO k 961 M 1(

004405 3!t: 14

CONFIDENTIAL

16

UNCLASSIFIED

Table V (U). Comparison of Methods for the Measurcntent of Vapor Pressure

Experimental DTA Knudsen kolniscopeparameter method metod reti hod

Sample required tor a series of 0.05 0. I to 0.5 I to I ()vapor pressure points (gm)

Sample required for a single 0.005 0.05 I to I 0vapor pressure determination (gni)1Pressure range (.to'rr) I to 760 0.00)1 to 0.7 5 to 7o0

Temprature range (C0 40 to 400 -40 to 15( -40 to 200

Time the sample is exposed Few minutes Few hiour [ew I1urNto ektvated temperatures

Time the sample is exposed seconds Minutes Minutes

to tie specific test temperaite I_ _

UNCLASSIFIED

17

. . . . . . .. . . . . . . . . . . . . . . ..N4~- **~'

UNCLASSIFIED

For EA 4923, there was an overlap of I vapor pressure point with another vaporpressure study. 14 The vapor pressure from this study was 18.4 torr versus 18.2 torr for the vaporpressure determined by the DTA method at 70 'C.

Vapor pressure data are available for GF, 15 ,16 VX, 16' 17 EA 135618 and EA 5365.17All of the literature data were obtained over a temperature range lower than the vapor pressurereported here. The extrapolated DTA datum was compared with the vapor pressure data point atthe highest reported temperature. Extrapolating our GF data to 30*C shows a deviation of 7% fromthe literature data point).5 There is about a 29% difference between the extrapolated DTA datapoint for VX and the vapor pressure measured at 100* C by Savage. 17 This discrepancy may be dueto a difference in sample purity. There is a 17% difference between the calculated vapor pressure forEA 1356 at 25*C and a data point measured by Fielder. 18 The correlation between the EA 1356data is satisfactory, considering the long extrapolation of the DTA data and the fact that samples ofdifferent purities were used. An excellent correlation exists between the extrapolated DTA data andthe data for EA 5365 measured by Savage 17 at 45'C. There is about a 4% difference between thetwo results.

Kemme and Kreps1 9 noted that discrepancies in vapor pressure data reported in otherstudies appear to be due more to differences in purity than to differences in experimental methods.Extremely high chemical purity could not be obtained on the agents investigated in this studybecause of the lack of chemical and thermal stability, small sample size, and difficulty involved inthe purification of samples. The presence of soluble high-boiling impurities generally causes adecrease in vapor pressure. Impurities which have a higher vapor pressure than the pure sample hascould increase the vapor pressure of a sample.

With pure samples, the DTA method will produce a vertical foreslope for the boilingendotherm indicative of a constant boiling point. If the sample is not pure (less than 99.5 molepercent), 4 there will be a deviation from the vertical foreslope, as the boiling range is no longerconstant. An increase in the foreslope, as vapor pressure is measured at higher pressures and highertemperatures, generally indicates the presence or generation of an impurity. The DTA method,therefore, has an advantage over other methods since it allows estimation of the purity and thermalstability of the sample at the moment the vapor pressure is being determined.14 Snyder, A.D., et al. Monsanto Research Corp. Final Report. Contract DAAA 15-68-C-0316. Physical and Colloid

Chemical Research on Agents (U). December 1970. CONFIDENTIAL Report.

15 Neale, E. PTP 341. The Vapor Pressures of Some Organic Phosphorus Compounds (U). April 1953.UNCLASSIFIED Report.

16 Melanson, B.M. Suffield Technical Note No. 49. Physical Properties of Some Toxic Agents and Simulants (U).March 1963. SECRET Report.

17 Savage. J.J. Notebook 8080. pp 49-52. April 197 1. CONFIDENTIAL Notebook.

18 Fielder, ,). r 3tebook 7318. p 109. December 1968. CONFIDENTIAL Notebook.

19 Kem.ne ..A.. and Kreps, S.l.. Vapor Pressure of Primary n-Atkyl Chlorides and Alcohols. J. Chent. and Ung.Data. )4, 98 (1969).

UNCLASSIFIED18

UNCLASSIFIED

From the generally good correlation of our data for both the agents and the standardcompounds with that of the literature values, it appears that the accuracy of our experimentalmethod is comparable to standard methods of vapor pressure determination.

The range over which the experimental data were obtained varied widely for differentcompounds, as can be seen in table Ill. The utility of the technique at low pressures is limited bythe accuracy of the pressure-measuring apparatus and the ability to maintain and control a specificlow pressure. At present, pressure measurements czaiinot be determined accurately below about 1tort. Mechanical problems in cooling the cell below room temperature have, thus far, limited theuseable range to temperatures above approximately 35*C to a maximum of about 500TC. Thehighest temperatures at which reliable data could be obtained was limited to the temperature atwhich decomposition of the sample in the cell became significant. Initial sample purity is also afactor affecting the upper temperature limit at which a useable endotherm can be generated. In allcases the upper temperature limit for the DTA method is above that for the isothermal techniques.

It should be noted that some of the data presented in table IV are values calculatedabove and below the experimental range. Thus, values outside of this experimental range are, ofnecessity, extrapolated values with a loss of accuracy corresponding to the degree of extrapolation.For this reason, the data as presented have been rounded-off to a degree consistent with theaccuracy of the experimental technique.

VI. (U) CONCLUSIONS.

A method for determining vapor pressure-temperature relations for chemical agents hasbeen developed using a modified differential thermal analysis (DTA) apparatus. Vapor pressure datafor 10 compounds have been generated. These compounds are: GF VX, EA 1356. P-A 2222, FA2223. EA 4923, EA 5365, EA 5403, FA 5414. and FA 5488. A computer program was used toreduce the experimental data and fit it to the Antoine vapor pressure equation. In addition.volatility and heat of vaporization were calculated for each compound over selected temperatureranges. The method permits vapor pressure measurements at higher temperatures and pressures thanafforded by conventional methods, such as the Knudsen cell and the isoteniscope. The dynanmicnature of the technique reduces problems of agent decomposition, and the method provides reliabledata. Only small amounts of samp!K are needed to determine a vapor pressure curve.

UNCLASSIFIED10

UNCLASSIFIED

LITERATURE CITED

I. Vassallo, D. A., and Harden, J. C. Precise Phase Transition Measurements of OrganicMaterials by Differential Thermal Analysis. Anal. Chem. L4, 132 (1962),

2. Krawetz, A. A., and Tovrog, T. Determination of Vapor Pressure by DifferentialThermal Analysis. Rev. Sci. Instrum. 23, 1465 (1962).

3. Barrall, E. M., Porter, E. S., and Johnson, J. Microboiling Point Determination at30 to 760 Torr by Differential Thermal Analysis. Anal. Chem. V. 1053 (1965).

4. Kemme, H. R., and Kreps, S. 1. Vapor Pressure Determination by DifferentialThermal Analysis. Anal. Chem. 41. 1869 (1969).

5. Smothers, W. J., and Chiang, Y. Differential Thermal Analysis: Theory and Practice.p 4 5. Chemical Publishing Co., Inc., New York, New York. 1958.

6. Penski, E. C., and Latour. L. J. EATR 4491. Conversational Computation Methodfor Fitting the Antoine Equation to Vapor Pressure-Temperature Data. February 1971. UNCLASSI-FlED Report.

7. Reid, R. C., and Sherwood, T. K. The Properties of Gases and Liquids. p 135.McGraw-Hill, New York, New York. 1966,

8. Thomson, G. W. The Antoine Equation for Vapor Pressure Data. Chem. Rev. 38.1 (1946).

9. Stull, D. R. Vapor Pressure of Pure Substances. Ind. and Eng. Chem. 39.517(1947).

10. Smith, A., and Menzies, A. W. C. Studies in Vapor Pressure: II. A Static Methodfor Determining the Vapor Pressures of Solids and Liquids. J. Am. Chem. Soc. 32, 1412 (! tlOy.

It. Thomson, G. W. Physical Methods of Organic Chemistry. Part 1. A. Weissberger.ed. p 193. Interscience Publishers, New York, New York. 114).

12, Lafferty, J. P. Notebook 6955.pp 6-8. February 1963, CONFIDENTIAL Notebook.

13. Link, R. Notebook 6355. p 42. August l1b0. CONFIDIENTIAL Notebook.

14. Snyder, A. D_. et al. Monsanto Research Corp. Final Report. ('ontrnct DAAA 15-68-C0316. Physical and Colloid Chemical Research on Agents (UI. December 1170. CONFHDIN-TIAL Report.

UNCLASSIFIEDI.R _1C D T 0AG S B IA MK NOT 1'4' jtj

UNCLASSIFIED

15. Neale, E. PTP 341. The Vapor Pressures of Some Organic Phosphorous Compounds(U). April 1953. UNCLASSIFIED Report.

16. Melanson, B. M. Suffield Technical Note No. 49. Physical Properties of Some

Toxic Agents and Simulants (U). March 1963. SECRET Report.

17. Savage, J. J. Notebook 8080. pp 49-52. April 1971. CONFIDENTIAL Notebook.

18. Fielder, D. Notebook 7318. p 109. December 1968. CONFIDENTIAL Notebook.

19. Kemme, H. R., and Kreps, S. I. Vapor Pressure of Primary n-Alkyl Chlorides andAlcohols. J. Chem. and Eng. Data. L4 98 (1969).

UNCLASSIFIED22

CONFIDENTIAL

GLOSSARY

(C) STRUCTURE AND NOMENCLATURE FOR COMPOUNDSDISCUSSED IN THIS REPORT (U)

(U) GF - ,yclohexyl methylphosphonofluoridate

0('113jP Q

(U) VX - d .h e thylphosphonothioatc

C113 .-'P S (',t14 N0 . 211-5 lh l. +

(C) V-A 1356 " ,thvkyclohexy1 tcthytlMhonotluoridat

!..

F; (11P

CONFIDENTIAL2+1

\ i

CONFIDENTIAL

(C) EA 2-222 0-methyl methylphosphonofluoridothioate

sI

CH3 -P-O--CH 3

F

(C) EA 2223 -0-cyclohexyl rnethylphosphonofluoridothioate

S

CH3 -. p--o-

F

(C) lEA 4922 3-mcln~hoxy cyclhtptatictrinc

(C) LEA 4923 -I -nwtjio,%cy-cjohcptarjct

CONFIDENTIAL

CONFIDENTIAL

(c) I-A 5365 -dimethylamituxthy I N.N-dime thtlyliphosplioriimidtotliorickate,

0

(CII~ N 1~('11~14 N (C113h

F

(c) VA 5403 - I-dimiihtly uiuoiiA-2-p~rnpyI NN-.Iitdyiiet)-iiosplioruiidoftuoridat

0I(CIt,),N p -0 (i~ p(11, N 101.1)

(c) VA W4 4 31nk

p ( 'M

VA 54M

CONFIDENTIAL

UNCLASSIFIED

APPENDIX

LINE PLOTS CONSTRUCTED FROM THE ANTOINE EQUATION

S.. . . . . . . ... .. . . . .

-7.*EA EA 5403:

E5488 -

EA 5414 4 4- -

I x

-- 1*>A--

C (LSrALE

Figure A- I (U). Log p Versus lI/T Curves for Selected Agents Described in Table IV

BestAV~IC~I3CopyUNCLASSIFIEDoCt A7

MUM PAE.N-OTP14

___ UNCLASSIFIED"I....--... . ... ... .

I .... .... L-L•... ..

T..{-. ' ...' . . .i . .- •- - ].. . ... . .

"I ,-

•- GF experimental data from 55f to 170"C•: .-L I . I _.

4 W'. |

EA134 EA 221231 -- : EA 4923- +1 EA 2222:- EA-:3.6 r. KI) ... , E KZ- ZI. .-: •• .... - i L.. . . ..

4--, -., 2 .3 , 9- . . • . 9•... .,

* L

I , : .4

* I

I ; . .. .• N

tx t

• " i-- . -A- ,- - i ..

IN

- .:-- ._I- - ___... ... .,_

. . . . . .. .

. ... .I-..--..-gi .._ &.._.......

I ., " _L. ....

-;

"0 : 60 240 2,4, 200 100 100 A O .O

Figure A-2 (U). Log p Versus l1T Curves for Selected Agents Described in Table IV

UNCLASSIFIED

tDISTRIBILIION LIST I

AftenY Copise Alwncy

FL)GFWOOD ARSENAL MANUFACTURING TECHINOLOGYDIRIRE(1ORA1 I-

Chemniciil & Plant% Division

OFFICE OF THE COMMANDER ATTN: SMIJEA.MT-C

Aswiatc Tech Directorftot Engineering DATeN: SMUEA-MT-n

ATT'N: SMUEA-TD- T': MEMD

F~OREIGN INTELLIGENCE OFFICE 3 DEPARTMENT 01: DEFENSEATTN: SMUEA-FI

VIGAL OFFICE. ATTN: SMUFA-LF I

I)Irc, tot, USAMUCOM operations Research Group Defense Documentation Center 2

ATTN: AMSMIJ-DR Camseronl Station

PlISIAMC Liaison Office 2 Alexandria, VA 22314

Record Set. RHA. APG-FA, Bldg.5 179 2 1tneItllgneAec

Authors; Copy. Chemical Laboratory2 DensItligceAnyATT'N: OIA-DI6E

TECHN~ICAL SUPPORT DIRECTORATE Washington, DC 20301

Technical Releases Division2 CntaItllgceAeY

ATecnica Libraryivsio ATTN: ORD/DDS&T

WATecNi:a LSti' DivTon Washington. DC 20505

Test & Evaluation Division I OFC 1rl UGO EEA

IiATTN: SMUEA-TS-T OF:Q I oiA SGD URGEN GEERA

PRODUCT ASSURANCE DIRECTORATE. HQ A ShiGRO-MOP-8 I0

Product Assurance Test Division WahItnD 01

ATTN: SMUEA-PA-T

p"roduct Quality Assurance Division US ARMY MATERIEL COMMAND

ATTN: SMfUEAPA-QD Commanding~ Ceneral

CHEMICAL LABORATORY US Army Matetiel Command

Chemical Research Division ATTN: AMCRD-WlI

ATTN: SMUT A-CIC II Washington. DC .10315

ATTN: SMUEA-CL-CAATTN: SMUEA-CL-COIATTN: SMUEA.CL-CP

Physical Researeh DivisionIATTN :SMUFA-CI -P

AATTN: SMUFACL-PR I Comtmanding Gtncrl

M. Deisiet Tcit Cminte

. ..... ltIo!41.DIAL LABORATORY ATTN: Toeeinial Llibmy

ATTN SMUMA-01 M*113 100. soldice\I Cmkt

ATTN SMVFA-BL-M 1,*i tlw%14% ItT 411

ATzcN. RSeVArch - t6i~lI i ARMY NIVNlTION2S COMMAXII

AtTN: SMUEA-111L-RC

ATTIN SMVt A4IL-TI I S Arfl) Muntwmis Comnt"4M~

AITN: SMM-A41,V ATTN A~mst-Rt A

ATIN AMSMVIkt -t't

ti V & NG DIRFMLTOkATVF 01%t AMMt-i\M

ATTNi Smut A-0V M )er ) 0711111

I nirtafttftt A vsl-fat Ofl ic

ATTx SwmVEA4)V

ATT S..V '\ji OV tmi IntsantY 5%tiwAI

ATTNIII a1 Petr lvcr pt. (1.-tV4 SptIr

AtTN S~UVIA4)-M 4INceiIieiini MR.( 04tMt!"

I MIUan4-o 110

DISTRIBUTION LIST I (Cont'd) D)ISTRIBUITION LIST FOR DD) 1473"%

Agency Copies Agency (opic.

C'omma~ndant Technical Support DirectorateUSA Chemical Center & School AT:SUAT-

ATTN: ATSCMA.AD ATN MUAT-I ort MctClellan. AL 36201 ATTN: SMUEA.TS-L 2OFPARTMENT 01: THE NAVY

Offtvtc in ChargeNaval Biomedical Research Laboratory, NSCIOa land, CA 94625

10

.......

CONFIDENTIAL .

DOCUMENT CONTROL DATA. R & D(Security clasificatiofn of title, body of abestrct and Index#ng ainotetlon must be entered when the overall repo0t Is cleaeillied

1. OMIGINA TING ACTIVITY (COrporte eOM00) 20. 09POAT SICURITY CLASSIFICATION

Commander, Edgewood Arsenal CONFIDENTIALAttn: SMUEA-CL-CPA oh. GRU,

Aberdeen Proving Ground, MD 210103. NqlPORl" TIIL.

VAPOR PRESSURE MEASUREMENTS OF SOME CHEMICAL AGENTS USING DIFFERENTIALTHERMAL ANALYSIS. PART I (U)

4. OESCRIP TIVE NOT1S (Type of tegprt and Ineluetve dates)

This work was started in February 1970 and completed in May 1971S. AtUTWORII) (FPilt name. midlle Mitiol, last name)

Frederic Belkin and Harry A, Brown. Jr.

S. liEPON T CA T I 7*. TO TAL NO. OF IAG S '7b. NP -S

March 1973 31 19SOL CON11TRACT OI GPRANT NO. W*. ORIGINATOWS RIPORT NUIMFRI(S)

J. 140. 1C No. IT061101A91A EATR 4710

I. sL OTHER RE9PONT NO $t 1 (Ary o ier numb*#e tiatm i•,' be a*&## #4

V.~W reportd.

to. OISTRNIOUTION STATE69EN1T

t-. 6UPWL9baEN'TA'ry NOTIES III. SPONSO4R1ING MILITASI* ACTIVITY

In-house laboratory independent research

(U) A method for determining vapor pressurir-temperature relations for chemical agents has been'

developed using a modified differential thermal analysis tI)TA) apparatus. Vapor pressure data for 10compounds have ben generated. These compounds are: GF. VX, FA 1356. I.A 2222. FA 2223 FA 4023,FA 5365. EA 5403, EA 5414, and FA 5488. A computer program was used to reduce the ext-rimentaldata and fit it to the Antoine vapor pressure equation. In addition. volatility and heat of vapxriiation werecalculated for each compound vver electcd lempcrature rangs. The method permits vaptor prc-.%%uremeasurements at higher temperatures and pressure% than afforded by conventional methods. %uchm a% theKnuden cell and the isotcniscope. T'he dynamni% nature of the technique reduces 1-foblem, of agentdecomposition. and the method provides reliable data. Only r.mall amount& of sample are needed todetermine a vapor prttsre curve.

14ý KEIYWORDS

DTA FA 222ZVapor pressure IA 22'3Volatility FA 4923"Heat of vaporization t A 5305Differential thermal analys.i t A 5403GF FA 5414V % F A 54KA

F A 1.,56 l:, . . .

9~~~~~ It. J .~RU

DD t.aeftv 1473 " .. bet CONF1111WNTIAL

Securtiy Classifimtton n ,_ _

L4. A I LINK 0 LINK C

KIgY WORDSROLS WT MOL. NT ROLE WT

/ •Ib bcwy Vje :&(Th paese"\sen~f

REQUEST FORIOR NOTIFICATION OF REGRADING ACTION DAEJUL 1 1 2006FILE

For use of this form, see AR 380-5; the proponent agency is OACSI.AMSRD-ECB-CB-CR

READ INSTRUCTIONS ON REVERSE SIDE BEFORE COMPLETING THIS FORM

TO: (Include ZIP Code) FROM: (Include ZIP Code)Defense Technical Information Center (DTIC) TD, ECBCATTN: DTIC-OCQ (LARRY DOWNING) ATTN: AMSRD-ECB-CB-CR8725 John 1 Kingman Road, Suite 0944 5183 BLACKHAWK ROADFt. Belvoir, VA 22060-6218 AND APG, MD 21010-5424AMSBRD-ECB-CB-SI/PATSY D'ERAMO

XHE DOCUMENT(S) DESCRIBED BELOW HAS/HAVE BEEN REVIEWED FOR REGRADING AND ACTION HAS BEEN TAKEN ASINDICATED. APPROPRIATE ACTION SHOULD BE TAKEN TO MARK YOUR COPIES AND NOTIFY ALL RECIPIENTS TO WHOMADDITIONAL DISTRIBUTION WAS FURNISHED IN ACCORDANCE WITH AR 380-5. DOCUMENTS CONCERNING THIS SAMESUBJECT SHOULD BE REVIEWED FOR POSSIBLE REGRADING.

LREQUEST DOCUMENT(S) DESCRIBED BELOW BE REVIEWED TO DETERMINE WHETHER THEY CAN BE DOWNGRADED ORDECLASSIFIED AT THIS TIME. (Include justification in the "REMARKS" section of this form.)

EREQUEST APPROPRIATE CLASSIFICATION/REGRADING INSTRUCTIONS FOR DOCUMENTS DESCRIBED BELOW.

DESCRIPTION CLASSIFICATION[

CONTROL NUMBER (TYPE, FILE REFERENCE, UNCLASSIFIED SUBJECTOR SHORT TITLE, REGRADING INSTRUCTIONSINDORSEMENTS, INCLOSURES)

OLD NEW

AD525359 Vapor Pressure Measurements of Some Chemical Agents Using CON UNCLASDifferential Thermal Anaylsis. Part 1 (U) - MAR 1973 Unlimited

REGRADED UNCLASSIFIED BY AUTHORITY OF ECBCORIGINAL CLASSIFICATION AUTHORITYUNLIMITED DISTRIBUTION

PRINTED OR TYPED NAME AND TITLE OF OFFICER SIGNATUREJ.H. ZARZYCKItechnical DirectorECBC OCA

DA FORM 1575, SEP 77 EDITION OF 1 SEP 62 IS g9SOLETE. USAPPC V3.00