FRANK J. SELLER RESEARCH LABORATORY

FJSRL-TR-82-0006

JULY 1982

DENSITIES, ELEC'TRICAL CONDUCTIVITIES,

VISCOSITIES AND PHASE EQUILIBRIA OF

1,3-DIALKYLIMIDAZOLIUM CHLORIDE -

ALUMINUM CHLORIDE BINARY AND

TERNARY MELTS

ARMAND A. FANNIN, DANILO A. FLOREANI,

LOWELL A. KING, JOHN S. LANDERS,

BERNARD J. PIERSMA, DANIEL J. STECH A

ROBERT L. VAUGHN, JOHN S. WILKES,

JOHN L. WILLIAMS

PROJECT 2303

40 •AIR FORCE SYSTEMS COMMAND

UNITED STATES AIR FORCE

MDT1ON STAbt M Un.i it0 8_ ufmstrlbuuv iUrajnited

Sr ..- r-. .-- •, .• ? ,• •- " ;• "- r- rv .¶ -- - . .... .- . ... V - - .. . • •

FJSRL-TR-82-0006

This document was preparea by the Electrochemistry Division, Directorateof Chemical Sciences, Frank J. Seiler Research Laboratory, United States AirForce Academy, CO. The research was conducted under Project Work Unit number2303-F2-10. Lowell A. King was the project scientist.

When U.S. Government drawings, specifications or other data are used forany purpose other than a definitely related government procurement oper-ation, the government thereby incurs no responsibility nor any obligationwhatsoever, and the fact that the government may have formulated, furnished orin any way supplied the said drawings, specifications or other data is not tobe regarded. by implication or otherwise, as in any manner licensing the holderor any other person or corporation or conveying any rights or permission tomanufacture, use or sell any patented invention that may in any way be relatedthereto.

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National Technical Information Service (NTIS). At NTIS it will be availableto the general public, including foreign nations.

This technical report has been reviewed and is approved for publication.

Lowell A.Kine Ariand A. Fannin, Jr, Lt CoProject Scientist Director, Chemical Sciences

WIliam D. Siuru) Jr., Colonel

Commander

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I. REPORT NUMBER 12. GOVT ACCESSION NO. 3. RECIPfENT'S CATALOG NUMBER

FJSRL-TR-82-0006 , lADA.I/ ,.9 . E

4, TITLE (ad Subtitle) 5. TYPE OF REPORT & PERIOD COVERED

Densities, Electrical Conductivities,Viscosities and Phase Equilibria of 1,3- Interim 6/81-7/82Dialkylimidazolium Chloride-Aluminum Chloride 6. PERFORMING ORG. REPORT NUMBERBinary and Ternary Melts

7. AUTHOR(&) Armand A. Fannin, Jr., DaniloTT".Floreaeini, 8. CONTRACT OR GRANT NUMBER(s)

Lowell A. King*, John S. Landers, Bernard J.Piersma, Daniel J. Stech, Robert L. Vaughn, JohnS. Wilkes, John L. Williams

9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT, PROJECT, TASK

The Frank J. Seiler Research Laboratory (AFSC) AREA & WORK UNIT NUMBERS

FJSRL/NC, USAF Academy, CO 80840*Universal Energy Systems, Inc. 2303-F2-10

Ani Dayton-Xenia Road. Dayton, OH 45432 .. ..It. CONTROLLING OFFICE NAME AND ADDRESS 12. REPORT DATE

The Frank J. Seiler Research Laboratory (AFSC) July 1982FJSRL/NC 13. NUvMSEAoF PAGESUSAF Academy, CO 80840 38

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Approved for public release; distribution unlimite

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molten salt.densityconductivityviscosity

19. KEY WORDS (Continue on reverse side if ne,'esaary and identify by block number)

'1%. ABSTRACT (Coqtinue n reveree side If necessary and Identify by block number)

/.xperimental values are reported of the specific electrical conductivities,densities and kinematic viscosities of representative examples of binary 1,3-dialkylimidazolium chloride-aluminum chloride mixtures. The electrical con-ductivities of ternary mixtures of 1-methyl-3-ethylimidazolium chloride, al-uminum chloride, and several organic and inorganic third components also arereported. All of these data were collected over wide temperature and com-position ranges. The phase diagram for the l-methyl-3-ethylimidazolium chlo-ride-aluminum chloride system was determined.

IFORM

DD jAN 73 1473 EDITION OF I NOV 65 IS OBSOL i'E

SECURITY- CLASSIFICATION OF THIS PAGE (When Data Entered)

FJSRL-TR-82-0006

DENSITIES, ELECTRICAL CONDUCTIVITIES, VISCOSITIESAND PHASE EQUILIBRIA OF 1,3-DIALKYLIMIDAZOLIUM CHLORIDE-

ALUMINUM CHLORIDE BINARY AND TERNARY MELTS

Lt Col Armand A. Fannin, Jr.2Lt Danilo A. Floreani

Dr. Louell A. KingMaj John S. Landers

Dr. Bernard J. Piersma2Lt Daniel J. Stech

Maj Robert L. VaughnDr. John S. Wilkes

Capt John L. Williams

JULY 1982Approved for public release; distribution unlimited.

Directorate of Chemical SciencesThe Frank J. Seiler Research Laboratory

Air Force Systems CommandU. S. Air Force Academy, Colorado 80840

II

TABLE OF CONTENTS

S lUMMARY i*i

PREFACE. . . . . . . . . . ............ ii.

INTRODUCTION . . . . . . . . . . . ..

-EXPERIMENTAL . . . .. .. .. .... ... .... 2

RESULTS AND DISCUSSION ................ ...... 7

REFERENCES . . . . . . . . . . . . . . . . . . . . 34

• iI

AcceSCAOfl ForNTIS Gr P•&tDTIC Tt3B

I;IDistributilol/

• j ~Availabilitt Codles

.Avail j nd/or l

i

SUMMARY

1'

* - Experimental values are reported of the specific electrical conductiv-

ities, densities and kinematic visccsities of representative examples of

binary 1,3-dialkylimidazolium chloride-aluminum chloride mixtures. The elec-

trical conductivities of ternary mixtures of l-iethyl-3-ethylimidazolium

chloride, aluminum chloride, and several organic and inorganic third compon-

ents also are reported. All of these data were collected over wide temper-

ature and composition ranges. The phase diagram for the 1-methyl-3-ethyl-

imidazolium chloride-aluminum chloride system was determined.

I II

I'I

4 ii

PREFACE "

Many binary compositions of 1,3-dialkylimidazolium chloride and aluminum

chloride are ionic liquids which are liquid near (and in some cases well

below) room temperature. They are potentially useful as electrolytes in bat-

teries, for electroplating, and in photoelectrochemical cells. They have also

been used as solvents in the investigation of a number of organic, organo-

metallic, and inorganic solutes. The work described here is part of a con-

tinuing study designed to develop new low temperature electrolytes for battery

applications. Experimental work is continuing, and theoretical modeling of

the results is in progress. More complete results and their interpretation

will be reported at a later date.

Dr. King gratefully acknowledges the financial support of the Air ForceI -I"Wright Aeronautical Laboratories. Dr. Piersma gratefully acknowledges his

support by the Air Force Office of Scientific Research as a University Res-

ident Research Professor at the Frank J. Seiler Laboratory. Maj Landers par-

ticipated in the project as a USAF Academy Faculty Research Associate. Lts

Floreani, Stech and Wilson contributed to this effort while on temporary duty

with the Frank J. Seiler Laboratory, awaiting Air Force assignment.

iii

INTRODUCTION

Molten salts have been considered as potential primary and secondary bat-

tery electrolytes for several years. As part of ongoing programs at the Frank

J. Seiler Research Laboratory and the Air Force Aero-Propulsion Laboratory, we

report here the specific electrical conductivities, densities, and kinematic

viscosities of several bi'Jary mixtures of 1,3-dialkylimidazolium chloride and

aluminum chloride over wide temperature and composition ranges. We also

report the specific conductivities of certain l-methyl-3-ethylimidazolium

chloride (MeEtImCl)-aluminum chloride binaries to which several organic and

inorganic compounds have been individually added. We have determined the

phase diagram for the MeEtImCl-AlC1 3 binary system over most of the poss-

ible composition range.

One other major class of room temperature molten salts has been studied as

a potential battery electrolyte and for other applications; that is the

1-alkylpyridinium chloride-aluminum chloride system. Extensive work has been

done on this system in various laboratories. Studies in room temperature

aluminum halide-containing melts in general were the subject of a recent

review by Chum and Osteryoung (1). The present study parallels our early work

on the densities, conductivities, and viscositiec of the alkylpyridinium

systems (2).

The dialkylimidazolium chlorides used in this study are shown below:

Compound Ri R9

MeMeImCl methyl methylcv+ NR C- MeEtlmCl methyl ethyl

MePruImCfl methyl n-propyl

MeBuImCil methyl n-butylBuBuInCl _n-butyl n-butyl

1

The rationale for the choice of these imidazolium salts has been discussed.,

elsewhere as has their synthesis and the preparation of the binary melts

(4,5).

The third components which were added to the dialkyl imidazolium chloride-K

aluminum chloride binaries were acetonitrile, propionitrile, butyronitrile,

benzene, xylene, and lithium chloride.

EXPERIMENTALF Sample preparation.- The dialkylimidazolium salts and their binary mix-

tures with AlCl, were prepared as described elsewhere, (4,5). Ternary mix-

4 tures were prepared by adding redistilled reagent grade third components to

previously prepared binary melts (except for LiCl, which first was dried by

prolonged heating just below its melting point). All sample preparation and

handling (except in sealed dilatometers and viscometers) was conducted in a

argon filled glove box (Vacuum/Atmospheres Company box and Model MO-40 DRI

TRAIN), having moisture and oxygen concentrations less than 10 ppm.

Density measurements.- Densities were measured in sealed Pyrex dilato-

metric tubes whose volumes had been calibrated with mercury or distilled water

in the conventional manner. Etched on each dilatometer was a reference mark

midway up the stem (6). Samples which could be handled conveniently as

liquids (except for the MeEtImCl binaries) were loaded into dilatometers with

bulbs on the bottom of a relatively small diameter stem. The volume of this

type of dilatometer to the reference mark was typically 6.5 cm', and that of

the stem typically 0,085 cm'/cm. The remaining samples were loaded into

straight tubes of typical volumes and cross sections of 1.5 cm' and 0.24

cm'/cm, respectively.

2

Weighings were made inside the glove box. Loaded dilatomneters were stop-

.pered, removed from the glove box, evacuated, and sealed with a torch. The

dilatometers were placed in a B. Braun Thermomix Model 1420 water bath, and

temperatures monitored with an Air Force Standard Platinum Reference Thermo-

meter. Estimated uncertainty in sample temperature was ±0.05 *C. At temp-

eratures below 20 0C and above 85 0C, the dilatometers were placed in the con-

stant temperature bath described below in the viscosity section. The experi-

mental measurements of sample volumes were made by measuring with a cathe-

tometer the distance of the bottom of the meniscus from the reference mark.

Cathetometer readings of the index mark Pand meniscus locations were made to an

accuracy of ±0.05 mm. Appropriate corrections were made in calibration and

sample measurements for bouyancy, thermal expansion, and meniscus shape

effects. Overall precision in density was estimated to be ±0.1% and ±1%

for samples in the large and small dilatometers, respectively.

Conductivity measurements.- The same conductance cell was used for all

samples, and is shown in Fig. 1. It was a Pyrex capillary approximately 0.5

cm long with a nominal i.d. of 0.05 cm. The capillary wi.s sealed to a 0.6 cm

i.d. Pyrex tube. Bright platinum wire coils were placed inside the larger

Pyrex tube, immediately above the capillary, aud on the outside surface of the

capillary. A thermocouple was also inserted into the larger Pyrex tube. The

assembly was immersed to approximately the same depth in small containers of

each sample. Before each filling the cell was carefully cleaned by washing

with acetonitrile and water and was dried in a 100 *C oven.

The conductance cell was calibrated at 25 'C using 0.1 demal aqueous KCI

(7). The cell constant was 214.93 cm , and was corrected for thermal

expansion as appropriate for each individual experimental measurement.

Conductivity measurements were made at 1 kllz with a Beckmani Model RGLS8A

conductivity bridge. Measurements at 1 kHz and 3 kHz were identical within

exp~rimental error, so no frequency corrections were considered necessary.

The sample containers were loaded and the conductance measurements made in

the glove box. The containers were immersed in a well stirred lninerai oil

bath to a depth where the surface of the sample was at least 5 cm below the

surface of the oil, in order to minimize temperature gradients within the

sample. Temperature stability of at least ±0.05 'C was attained over the

entire temperature range, and the actual temperatures were known to within

±0.1 *C. A Bayley Model 124 proportional temperature controller was used.

overall precision in specific conductivity was estimated to be ±1%.

Viscosity measurements,- A closed, submersible, all Pyrex viscometer

was employed, anid is shown in Fig. 2. The viscometer could be opened for

emptying, cleaning, and refilling, then resealed. The viscometer was calib- Irated at various temperatures with cyclohexanol, ethylene glycol, and glyc-er-

ol. Flow times for calibration varied between 19 and 4550 s. The calibration

data were fit to a straight line passing through the origin of a time-

*kinematic viscosity plot. The average deviation of calibration data from the

* line was ±1%.

The viscometer was mounted on a vertical platform submerged in a well

stirred silicone oil bath, The platform could be rotated in the vertical

plane by remote control to fill the upper. chamber of the viscometer. The

passage of the liquid meniscus past two arrow marks above the capillary was

timed with a precision of better than ±1.5% with a. stop watch. At least six

* runs were made for each sample at each temperature, and the mean efflux times

were used in the calculation of kinematic viscosity.

4

S.•= . , i •,• • ••• .• ,. - • .I . .. . . . . - ..•• •_ " • • • • .-. .--.------ ,• , • • '.

9 CM

2 CM

10.5 CM

12 CM

Fig. 1. Conductivity cell. Fig. 2. Viscometer.

The oil bath was equipped with submerged heaters, but the principal temp-

Lrature control was achieved with submerged coils attached to a NESLAB Endocal

Model RTE-9B refrigerated circulating bath. The oil bath could be maintained

at temperatures ranging from -15 0C to 100 'C with a long term stability of

±0.5 *C. The actual sample temperatures were known to within ±0.1 'C at

near ambient temperatures and ±0.5 'C at the temperature extremes. On com-

bining the above uncertainties with those in composition and misalignment of

4 the capillary from the vertical, an overall error in kinematic viscosity of

±2.5% was estimated.

Melting nnd freezing point measurements.- The solid-liquid phase tran-

sitions, and in some case, glass transitions were measured by two methods;

visually and by differential scanning calorimetry (DSC). Since most tran-

5

- * -c rIr. ., . mr. -.- -•**r•*r" P 9W W - - r1W . *

sitions were at sub-ambient temperatures, a conventional melting point appar-

atus could not be used for the visual determinations. A temperature con-

trolled dewar (Wilmad WG-821 variable temperature insert, WG-836 transfer

dewar, and WG-838 heater) designed for an electron paramagnetic resonance

(epr) cavity proved to be convenient for measurements to -1000 C. Samples

were sealed in quartz epr tubes and their temperature was controlled by a

stream of dry N2 gas cooled by a glass coil inmiersed in liquid N2 .

The phase transitions were observed with a magnifying glass chrough the double

quartz walls of the dewar. Many of the samples supercooled, so melting

points, rather than freezing points, were taken as the true transition temper-

ature. Glass transitions were clearly distinguished by an increase in viscos-

ity with cooling, terminated by a sudden fracturing of the melt at the glass

transition temperature.

The differential scanning calorimetry was done on a Perkin-Elmer DSC-2

calorimeter fitted with the sub-ambient accessories. Temperatures below 30 'C

were attained using liquid nitrogen cooling with a helium purge of the DSC

head. The instrument was calibrated with acetone and with water before and

after each set of experiments. The samples were contained in stainless steel

large-volume pans which were loaded and sealed inside a glove box. The temp-

erature was scanned at 10 or 20 0 C/min.

Most compositions were observed both visually and by DSC. The two methods

usually agreed within less than ±1 0C, with an estimated "worst case" error

of ±2 *C.

6

( RESULTS AND DISCUSSION

The concentrations of binary melts are expressed as the "apparent mole

fraction" of AICd 3 . This is the melt composition calculated as though the

melt were comprised of monomeric AlCl3 and the appropriate imidazolium

chloride. In fact, however, probably no measureable AlCl3 exists in these

melts (8); they are comprised of imidazolium cations and Cl, AIC 1 4,

and A1 2 CI 7 anions. The molecular weight of the binary melts is

given by

M = M + 133.34 x N 0(1-N) (1)

where M is the molecular weight of the dialkylimidazolium chloride and N is

the apparent mole fraction of AIC1 3 . Notice that this is not the custom-

ary formula for the evaluation of the molecular weight of a binary molten salt

mixture; rather it allows for the fact that the number of ions present in the

4 mixture is governed solely by the number of moles of imidazolium chloride

present, and is not changed by the addition of AIC1s (9).

Concentrations of species in ternary melts are expressed as though a third

4 component were added to an existing binary melt (which, in fact, is how they

were prepared). Aluminum chloride concentration is expressed as the apparent

mole fraction in the original binary, as defined above. The mole fraction of

4 the third component, X3 , was calculated from

X3= moles third / (moles third + moles binary) (2)

7

1. - . -

where the moles of binary can be calculated from its mass and eq. 1. Here

again, the third component does not contribute to the production of ionic

species. In the case of added LiCl, the third component does contribute ionic

species, and this method of expressing concentrations is no longer suitable

for making comparisons. (The actual mole fraction of LiCI in the one ternary

melt studied was 0.052, whereas eq. 2 would have yielded the value 0.15.)

The raw experimental data were converted into densities, specific conduc-

tivities and kinematic viscosities, and are presented for the binary melts in

Tables I, II, and III, respectively. Included in Tables I and II are the

densities and conductivities of the pure 1,3-dialkylimidazolium chlorides.

The viscosities of the pure salts and of the two lower AlClI content

binaries with MeMeImCl were not measured because of the experimental diffi-

culties which were anticipated in working with these relatively high melting

compounds in the present viscometer. It was not possible to work at an appar-

ent mole fraction AlCI 3 higher than 0.666, for the melting temperature

rose extremely rapidly with increasing AIC13 content in this composition

region. Pure aluminum chloride is a non-electrolyte, and its physical pro-

perties are not considered here.

The specific conductivities of the ternary melts to which propionitrile

has been added are given in TLble IV. Densities and viscosities of the

ternary mixtures have not been measured.

The MeEtImCl-AIC 1 3 system was chosen as a "base-line" melt, primarily

because of its relatively favorable conductivity and viscosity behavior and

its wide liquid range, as shown below. Other studies are underway in our lab-

orat-;y on nuclear magnetic resonance spectroscopy of this system and on the

electrochemical behavior of a number of inorganic and organic solutes in

MeEtImCl-AICI 3 melts.

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or * * * * X r * * * * C or * * * * * or .L w-uw L w-")'oi'U Wl~S 'U ClAI a.-0ý e_ Moo~ OOT0 ' S0 Ch QC

.4V4 Vw4 .4 .s

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a> aaa

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a, w W r- w 4 r r- r- " r- w CI-cown~ au WcuW4WPW4m WIir 4W qIDý c i( W'W~ 4W Mue nw UWWWIfWS0C(

I cu en v4rv CUlw) nWCUC4'U) 0 *4C en V44Ot *se rwo IIIxO

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15

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16-

.. 4I rUU)LI ()W~C v N Wmv--w 0 WMI.DOflQ""O 4w(mr'-mm I-- wlO-mwm- cy - %p (U-4 r- (0

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.- 4 (D o~ Ln T T)m (T (U-)141qu.4I I w T P V"ITr

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m r IT ()9 (U V-1 4 0)W fu 4 T -4 0) r UW tAV

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[~to

*.*~~~~~*~(7 hM (Dr-~- LA (1)r~ *M V V m- W- *-A .- rwi-tT mj 0- v

T-49 >D 0O )c h0Wlflt r- ( 0U T U- v> Wmh r-O W tC )1FV

Cy- WW W ,0o44c- W'nOWCn (

F. 0D01l 0< 0 D *D (4 Wt........ow 0o ... Wr(D -7flubD(DII-i~~~< 9 W9 D( (D w-rW fllro-rON W (Lff~r N D (DW

.4 .. 4 . . . .I 00>0 D (S)C D0 D>00

A 1 OF- (DOF-c e

*M oo WLDLLAifWWWUv 00 roWWWW tDW IWf-I *) * 9 * 9 M 9f (D CA9 .

*q M D &0 00D0 0 a # 0Q-000000<D0O

fg > >.4C

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0 : I ILL aIxo.. .WO

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180

ft- V *T :q-4 00 (D N* 00i~ ONr C: r Y rw r 4 % rrý'~~ %Dnt; r-** 0 (n ~ %D I

v41 C;n(-tcn w O -4 ONwoý -4 r n-%D w nNDm n%0 wI CN c'

eir r,- OI C! 0O0 1-1%10InltfInl f OWN Wo IC -C4r 0In r

00NO O 00

1- 0 r4C 4C4MD 00 ) DC , r4,4-I,-v I-. 000v-Na 0 0-lwI wI

$4 C

"04r N 00 v-NCOC- M In 00\'.NCO0OON00 0 0nIflCoO- fl" 4N 0m

1 Hi C Q n- o in f. . .*

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-H0 C4'nC It) 0r 0 C NtnO n-, 0nn% 0v-.# ýt LnD0ONN m mr0\ .

144 1: v4 -4

0 0

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4 r-I INI n N- Ný cn ON. i'4. 0 N N)0' WtN cI) vI N1 C- 0c) %D r-. It'. %T

0 I 0 o)%.-týt - c- N%'. 'D-4 - WN~ . o 'Tr 4Ncja In NO' 0040Z (n ( 40 00 O4-I o 000 0000

44 0 . in * . * If ON * * m *4 *C)0r IC4 CI, 4 ,-v.N CIt V.C NC I*CIn' N0 P It'I

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I- v-4 III II II ý 0c)ý rlrl n r- 0U)r

In 1.4 ,. .a 1to. ICIC

H~~ I 4Izi. 0 C v-Cv-1' I I ~ ~ I ICO '0

19

0

(0

41J

0

40 C: N4I 40 O qC, 0- I ' )U o0

C,4 -4 C4 4y) -1.o 'Jl L

0- m ii IiC)0 % 0 n10 r a)4 0I

C; Cý ( (ý r:

I C1 \Q-C C r ,CH .oýo~ 'o ~ ~ r O0co A 0 0 ~

20

The freezing, melting, and glass transition data for MeEtImCl-AlCI 3

"binaries are shown in Table V.

Table V. Solid-Liquid Phase TransitionTemperatures for MeEtImCl-AlCI 3..

K T N T N T

0.00 84 0.36 -68 8.56 -18O.0S ?2 0.38 -72 0.58 -230.10 62 0.40 -7S 0.60 -310.15 S4 0.41 -27 0.61 -330.20 Al 0.42 -24 0.62 -950.25 39 0.44 -19 e.64 -950.30 32 0.46 -10 0.66 -96e.31 28 0.48 -3 0.68 450.32 21 0.50 7 0.70 790.33 19 0.S2 -3 0.73 1100.34 17 0.s4 -9 1.00 195

a Temperatures in *C.

The solid-liquid phase diagram for MeEtImCl-AlCl 3 binary melts is

shown in Fig. 3. Qualitatively, the phase equilibria are similar to those

reported by Hurley and Weir for !-ethylpyridinium bromide - aluminum chloride

binaries (10). They are not qualitatively similar to the chemically similiar

system NaCl-AICl,, as is evident from Fig. 3. All of the melting tran-

sitions are lower than for any previously reported chloroaluminate melts. In

two regions the temperatures for the transitions abruptly became lower, then

abruptly rose again. The transitions in these low temperature regions were

glass transitions, and all attempts to induce true freezing for these compo-

sitions were fruitless. The glass transitions were clearly identified by DSC

(slope change rather than a peak) and visually (fracturing of -he melts rather

than solid formation). The melting points for mixtures having aluminum chlor-

ide mole fractions greater than 0.666 were done in sealed tubes and presumably

under significant AIM. vapor pressure. No measurements were made on com-

positions greater than a mole fraction aluminum chloride of 0.73.

21

NaCI-AlC13

CD,

L 200

SMeEtImCI-AICI3

I-

0.0 0.2 0.4 0.6 0.8 1.0MOLE FRACTION AICI 3

Fig. 3. Phase diagram for MeEtImCl-AlCI 3.

Experimental densities were least squares fitted to equations of the form

P = P0 + P, (t - 60) (3)

where t is the temperature in 'C. The values of the fitted parameters are

given in Table VI, together with the valid temperature range for each compos-

ition. No unusual features were found in the densities. As expected, there

was a relatively smooth density decrease as the size of the imidazolium cation

increased. This is illustrated in Fig. 4 for N = 0.50 melts at 60 °C; similar

behavior was noted at other compositions and temperatures.

22

Table VI. Least Squares Fitted Parameters for BinaryMelt Densities.a

R1 R3 N P0 pX10x Tmin Tmax

METHYL ETHYL 0.00 1.1378 -7.8253 31 91METHYL ETHYL 0.31 1.1955 -6.0420 -20 tooMETHYL ETHYL 0.36 1.2151 -6.8975 -20 100METHYL ETHYL 0.42 1.2244 -6.3662 -20 100METHYL ETHYL 0.48 1.2531 -7.0695 0 100METHYL ETHYL 0.51 1.2667 -7.6121 0 10tMETHYL ETHYL 0.56 1.2933 -8.9639 -11 100METHYL ETHYL 0.61 1.3205 -8.5937 -20 100METHYL ETHYL 0.66 1.3498 -9.0610 -20 100METHYL METHYL 0.00 1.1745 -5.5647 127 151METHYL METHYL 0.33 1.2739 -7.5142 60 152METHYL METHYL 0.50 1.3053 -6.7460 59 152METHYL METHYL 0.66 1.3725 -9.1391 11 83METHYL PROPYL 0.00 1.0918 -7.3377 11 83METHYL PROPYL 0.33 1.1734 -6.9507 11 81METHYL PROPYL 0.50 1.2348 -7.8879 11 81METHYL PROPYL 0.66 1.3198 -8.9647 11 81METHYL BUTYL 0.00 1.0965 -6.0315 11 83METHYL BUTYL 0.33 1.1590 -4.1182 11 82METHYL BUTYL 0.50 1.2113 -7.6234 11 81METHYL BUTYL 0.66 1.303.0 -8.8205 11 82BUTYL BUTYL 0.00 1.0085 -6.7284 28 93

BUTYL BUTYL 0.33 1.0841 -6.5641 11 82BUTYL BUTYL 0.50 1.1391 -7.1948 11 82BUTYL BUTYL 0.66 1.2237 -8.1797 11 82

Temperatures in 0C; densities in g/cm

•MeMe1.30- - e TEMPERATURE 600C

,_ MOLE FRACTION AIC13= 0.50

CO MeEt:1.25 - S "•1ePr

1.20

w

1.15I I ! I IB u

2 3 4 5 5 7 8NUMBER OF ALKYL GROUP CARBONS

Fig. 4. Dependence of density on imidazolium cation size.

23

The composition dependence of the density of MeEtImCl-AlC] 3 melts at

60 0C is shown in Fig. 5. Density appears to be a monotonic function Af

AlCl3 content. Similar behavior was observed for other temperatures. For

MeEtImCl-AICI3 melts the density at each experimental composition lid

temperature was obtained by least squares fitting the methyl-ethyl billary

densities in Table I (excluding pure MeEt~mCl) to the equation

= a 0 + a, (N - 0.5) + a 2 (N - 0.5)2

+ a, (t - 60) + a, (t - 60) (N - 0.5) (4)

where the fitted values of the coefficients are a 0 1.26229, a,

0.456947, a 2 0.602142, as -7.67027 X 10- and alt

-8.97573 X 10 4.

1.35- I I I

TEMPERATURE :60%O

CI)

2 1.30 MeEtImCI-AICI 30

1.25

I.-Iz 1.20

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7MOLE FRACTION ACI 3

Fig. 5. Dependence of density on MeEtImCl-AlCl 3 melt

composition.

24

. . . . .. . - . .. . . . . . .. .- -. .-.-. .- -.. . . . . . .. . . .--. . . . . . . . .- . . . . . .. . . . + -_•. . . . • . . • . . . .

We assumed the dependence of density upon AlC13 content would be

similarly monotonic for the other four dialkylimidazolium chloride - AlCi,

systems, and therefore measured densities only at AICls mole fractions

0.00, 0.33, 0.50, and 0.66.

Experimental specific conductivities were least squares fitted to equa-

tions of the form

K= + K' (t- 60) + K 2 (t -60)2 (5)

The values of the fitted parameters are giveýn in Table VII, together with the

valid temperature range for each composition.

The dependence of specific conductivity on composition and temperature was

not as simple as for density. The dependence on cation molecular weight was

not as regular as for densities. A typical representation of this behavior

can be seen in Fig. 6, where the conductivity of equimolar MeEtImCl-AlClI

is nearly as high as that of the corresponding dimethyl salt binary, and very

substantially higher than that of the methyl-propyl analog. Similar behavior

was noted at other temperatures and compositions, as shown in Figs. 7 and 8.

These latter two figures clearly show that the specific conductivity is mark-

edly dependent upon composition of the melt, with equimolar melts being the

best conductors. The dibutyl system appears to be an exception to this at low

temperatures, where the AICl3 rich melt is the better conductor. In the

basic composition region, the relative decrease in conductivity for imidazol-

ium rich compositions becomes greater at lower temperatures, as can be seen by

comparing Figs. 7 and 8. (Missing data on these figures correspond to samples

below their melting points.)

The effects of temperature and melt composition on the equivalent conduc-

tivity of MeEtImCl-AlCls melts are shown on Fig. 9.

25

Table VII. Least Squares Fitted Parameters for BinaryMelt Specific Conductivities.2

R1 R3 N Koxle1 K1 xIe K2 xIe0 Tmin TmaxMETHYL ETHYL 0.00 0.5485 3.0871 6.4687 s2 110METHYL ETHYL 0.30 1.0401 3.648? 3.3282 36 58METHYL ETHYL 0.33 1.2276 4.0044 3,186 21 104METHYL ETHYL 0.34 1.3301 4.1150 3.4135 R2 100METHYL ETHYL 0.36 1.5267 1.4399 3.3888 8e leeMETHYL ETHYL 0.40 2.0239 5.0962 3.349? 16 85METHYL ETHYL 0.44 2.7631 S.7S40 2.5818 31 leeMETHYL ETHYL 0.48 3.8661 6.7385 2.5829 19 56METHYL ETHYL 0.49 4.1523 6.7567 2.1262 17 teoMETHYL ETHYL 0.50 4.4799 7.0092 1.9378 22 100METHYL ETHYL 0.51 4.3883 6.8528 1.?390 30 100METHYL ETHYL 0.52 4.24S4 6.6614 1.8959 18 I16METHYL ETHYL 0.58 3,6404 5.9530 2.1441 36 s8METHYL ETHYL 0.64 3,0935 4.8956 1.4423 17 100METHYL ETHYL 0.66 2.9277 4.6334 1.3388 22 104METHYL METHYL 0.00 -5.0593 15.8865 1.3204 153 164METHYL METHYL 0.33 1.4978 4.4066 4.656S 80 106METHYL METHYL 0.50 4.6324 8.4086 0.7210 80 110METHYL METHYL 0.66 3.1296 5.3115 1.?539 20 100METHYL PROPYL 0.00 0.2087 0.7552 4.8038 70 152METHYL PROPYL 0.40 1.2284 3.5281 2.7283 21 100METHYL PROPYL 0.50 2.8821 5.4980 2.1200 26 100METHYL PROPYL 0.60 2.5669 4.6650 1.6184 30 100

METHYL BUTYL 0.00 0.1231 0.1466 3.2Z60 75 110METHYL BUTYL 0.33 0.5726 2.0957 2.2568 36 100METHYL BUTYL 0.50 2.4127 4.6583 1.9272 18 100METHYL BUTYL 0.66 2.0170 3.6113 1.3517 18 100BUTYL BUTYL 0.0e 0.21S5 -0.9381 8.0692 102 11eBUTYL BUTYL 0.33 0.2268 0.88280 1.3791 6s 100BUTYL BUTYL 0.50 1.3407 2.9590 1.6109 21 100BUTYL BUTYL 0.66 1.4003 Z.6490 1.08825 18 100

Temperatures in *C; specific conductivities in ohm 1 cm 1

~0.050.05 MeMe.• ,•:•• MeEt TEMPERATURE =60*C

MOLE FRACTION AIC 3 :0.50

S~BuBu

0

I-I

RU 0.0310. 2 3 4 5 6 7 8

NUMBER OF ALKYL GROUP CARBONS

Fig. 6. Dependence of specific conductivity on imid-

azolium cation size.

26

- 0.08 TEMPERATURE-- OOC 1000

. 0.06

S0.04 MeBu

0- / BuBuo 0.02

w 0.00we----- IjI I I I IC- 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7Cl)

MOLE FRACTION AIC13

Fig. 7. Dependence of specific conductivity on R1 R3 ImCl-A1C1 3- melt composition at 100 *C.

0.025 1 1TEMPERATURE- 250C

0 0.020 t -

I- 0.015-

MePr

0.010-O Me Bu0U 0.005-_o 0.005 BuBu

U-

wU 0.000 I I Ia. 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7CoMOLE FRACTION AIC13

Fig. 8. Dependence of specific conductivity on RIR3 ImCl-A1Cl 3

melt composition at 25 *C.

27

.1.

TEMPERATURE0

0.8

0.4

0.0 MelEtImCI-AICn 3

K 00.3 0.4 0.5 0.6 0.7

MOLE FRACTION AIC13

Fig. 9. Dependence of equivalent conductivity onMeEtImCl-AlCI3 melt composition and temperature.

Work is now in progress on theoretically modeling the conductivities of

these binary melts, so that the experimental results can be matched to equa-

tions derived from the transport model chosen. As was observed in

1-alkylpyridinium-AICls melts, the equivalent -onductivities did not dis-

play Arrhenius behavior very satisfactorily. This work will be reported later.

The kinematic viscosities given in Table III were converted to absolute

viscosities by

P =o (6)

The absolute viscosities of the MeEtImCl-AlCl3 melts were determined using

densities calculated from eq. 4. Kinematic viscosities of the remaining bin-

ary melts were measured at the ;ame compositions Pt which their densities were

28

determined. Therefore densities used in eq. 6 for these melts were calculated

from eq. 3.

The absolute viscosities were least squares fitted to equations of the form

loglo n 1 no + nl/T + n2/T2 (7)

where T is the temperature in kelvin. The values for the fitted parameters

are given in Table VIII, together with the valid temperature ranges for each

composition.

Table VIII. Least Squares Fitter Parameters for Binary MeltAbsolute Viscosities.a

R R N no0 ?71 X ×l) q 2 X×1O TmIn Tmix

METHYL ETHYL 0.31 7.9219 -6.1188 13.3555 10 9gMETHYL ETHYL 0.36 4.3939 -3.6006 8.7177 10 8gMETHYL ETHYL 0.46 1.7983 -1.8460 5.1768 11 98METHYL ETHYL 0.33 0.7459 -3.9566 1.7028 t2 92METHYL ETHYL 0.61 2.5833 -0.8276 5.7888 20 g8METHYL ETHYL 0.66 0.1483 -1.4269 2.1597 g 98METHYL PROPYL 0.33 8.0934 -6.2378 13.7206 11 81METHYL PROPYL e.5e 0.9359 -1.0317 3.5183 It 81METHYL PROPYL 0.66 1.5723 -1.3605 3.7797 11 $1METHYL DUTYL 0.33 4.6521 -3.9661 10.0434 20 82METHYL BUTYL e.se 2.5339 -2.e077 S.0078 2e 82METHYL PUTYL 0.66 1.6298 -1.40C8 3.9005 11 82BUTYL BUTYL 0.33 2.7968 -2.6367 7.9071 11 82BUTYL OUTYL 0.50 2.0506 -1.7679 4.8542 11 82BUTYL BUTYL 0.66 1.5038 -1.3622 3.9500 11 82

A Temperatures in *C; absolute viscosities in cP.

As implied by eq. 7, the absolute viscosities did not exhibit Arrhenius

behavior. This is in contrast to the l-alkylpyridinium-AiClI melts, which

did obey the Arrhenius equation (over a somewhat smaller experimental temper-

ature range) (3). The viscosities of the imidazolium melts were "mirror

images" of their equivalent conductivities. Representative viscosities are

shown in Fig. 10. The dependence of viscosity on the size of the dialkylimid-

azolium cation is even more anomalous than the conductivity behavior. Figure

29

11 shows that MeEtImCl-AlCl3 melts have substantially lower viscosities

than do the other melts studied. The theoretical modeling of transport

pheiomena cited above includes modeling of absolute viscosities.

3.0 IiI l

S2.5 MOBU

MoPr B U t3 U

2.00

Me-) TEMPERATURE

S1.5

o2500

10*.1 50 00

75000 .5 ., l. IIIIlIJ

0.3 0.4 0.5 0.6 0.7

MOLE FRACTION AlC13

Fig. 10. Dependence of absolute viscosity on meltcompoitioa and temperature.

The experimental specific conductivities of the ternary melts (including

those presented in Table IV) were least squares fitted to eq. 5, and the

resulting parameters are given in Table IX, togcther with the valid tempera-

ture range for each composition. Addition of the relatively polar molecules

acetonitrile and propionitrile to MeEtImCl-AlCI 3 binaries increased the

specific conductivity. Butyronitrile produced a smaller but still significa'nt

improvement in conductivity. The conductivity increases presumibly were due

to the lowering of melt viscosities; viscosities of the te-nary melts have not

been measured, but the solutions appeared to the eye noticeably more fluid

when they were handled.

30

I II

11 TEMPERATURE 60 OC01

MOL.E FRACTION AIC13 :0.50

Bu-u

S1.0! 0 Musu

MeMeI•Il

OgLi... MeEt3//'LF•~O•o306

0.8_ _ __I_ _ _ _I I I

2 3 4 5 6 7 8

NUMBER OF ALKYL GROUP CARBONS

Fig. 11. Dependence of absolute viscosity on imidazoliumcation size.

Additions of benzene had veiy little effect on conductivity, and xylene

significantly lowered the conductivity. Only small amounts of LiCi markedly

lowered the specific conductivity. Some of these effects may be seen in Fig.

12.

The organic cosolvents appeared to be soluble over large composition

regions. They apparently were miscible in all proportions with the equimolar

MeEtImCl-AlCl 2 binary melt at room temperature. The nitriles were mis-

cible in all proportions with N - 0.33 melts. An immiscibility region was

observed from 0.10 > X3 > 0.33 for propionitrile in the N = 0.66 binary

melt. In basic melts LiCl was the only alkali chloride that had a substantial

solubility (up to 0.1 mole fraction). In acidic melts all of the alkali

chlorides were soluble up to at least 0.1 mole fraction, but many of the

31

resulting ternaries were no longer liquid at room temperature. Alkali chlor-

ide solubilities were sharply reduced in equimolar melts.

Table IX. Least Squares Fitted Parameters for Ternary Melt SpecificConductivities.a

THIRD COMPONENT N X3 KOX10 KIX1X K2 XlI Tmin Tmax

ACETONITRILE 0.33 0.72 3.1083 5.4505 - 1B 80PROPIOMITRXLE 0.33 0.17 1.8436 4.5419 2.5903 14 leePROPIONITRILE 0.33 0.30 2.3086 5.0440 2.671S 31 leePROPIONITRILE 0.33 0.6S 4.3398 5.63S9 0.9570 28 100PROPIONITRILE 0.33 9.79 4.8528 4.9701 0.6041 21 99BUTYRONITRILE 0.33 0.14 1.4721 4.2394 3.4535 27 116BUTYRONITRILE 0.33 0.32 1.9577 4.6074 4.0041 28 100ACETONITRILE 0.50 0.7? 6.1811 7.5687 - 19 100ACETONITRILE 0.50 0.77 7.3380 8.0714 -0.2533 17 100ACETONITRILE 0.50 0.87 8.4408 9.1128 - 30 1o0ACETONITRILE 0.50 0.93 9.6865 8.7136 - 18 100PROPIONITRILE 0.50 0.21 5.2429 7.2817 1.4231 20 100PROPIONITRILE 0.50 0.36 5.9837 7.5e0o 1.0658 21 100PROPIONITRILE 0.50 0.75 7.S696 6.7759 -0.7188 17 100PROPIONITRILE 0.50 0.84 7.7976 6.4320 0.6093 1? 100PROPIONITRILE 0.50 0.91 6.6727 4.7537 1.0422 16 100BUTYRONITRILE 0.50 0.18 4.5765 7.0354 1.3607 29 100BUTYRONITRILE 0.50 0.31 4.8747 7.0043 1.3644 35 t0oBUTYRONITRILE 0.5e 0.64 5.6268 6.6056 O.5578 30 99BUTYRONITRILE 0.50 0.31 4.8351 5.1629 0.0991 30 19BENZENE 0-50 0.64 S.1047 6.8984 1.1378 is tooBENZENE 0.50 0.78 4.5274 4.8981 - 81 70BENZENE 0.50 0.8? 3.9348 3.8973 - 18 60XYLENE 0.50 0.03 4.2946 6.7084 1.8978 17 100XYLENE 0.50 0.23 4.2241 6.467s 1.4934 34 100XYLEME 0.50 0.73 3.524i 4.6637 - 85 t00XYLENE 0.60 0.27 3.4723 5.2782 1.4164 18 100PROPIONITRILE 0.66 0.28 2.6691 4.5585 1.4563 26 100PROPIONITRILE 0.66 0.88 5.6048 5.4898 0.1561 22 100

-Temperatures in deg. C; specific conductivities in ohm- cm-.

The greatest conductivity improvements were with acetonitrile and propio-

nitrile. At the highest temperatures reached in this study, acetonitrile

evaporated rapidly out of the liquid phase, but propionitrile did not. The

latter counlvent therefore was chosen as the "base-line" third component. A

detailed study is now underway of the density, conductivity, and viscosity of

propionitrile in MeEtImCl-AlCl 3 within the composition matrix 0.46 < N

< 0.54 and 0 < X3 < 0.75.

32

2 0.07 r 1 1 1 1 1 1 1 "

0.06- TEMPERATURE" 25° ACETONITRIL E

0• 0.05 - PROPIO NITRILE,,d

0.04 -MOLE FRACTION AICI 3

-- ~IN B•N A .Y

o .BUTYRONITRILEz 0. 0 2r0

o 0.01 L

L MeEtImCl-AICI 3 BINARIESL) O 0 - iI I I I I

a. 0.0 0.2 0.4 0.6 0.8 1.0MOLE FRACTION OF THIRD COMPONENT

Fig. 12 Specific conductivity of ternary melts.

33

REI ERENCES

1. H. Chum and R. A. Osteryoung, in "Ionic Liquids," D. Inman and D.Lovering, Editors, p. 407, Plenum Press, New York, NY (1981).

2. R. A. Carpio, L. A. King, R. E. Lindstroi,, J. C. Nardi, and C. L. Hussey,J. Electrochem. Soc., I2.6, 1644 (1979).

3. J. S. Wilkes and C. L. Hussey, Frank J. Seiler Research LaboratoryTechnical Report FJSRL-TR-82-0002, USAF Academy, Colorado, 1982;ADA 111651.

4. J. S. Wilkes ard J. A. Levisky, Frank J. Seiler Research LaboratoryTechnical Report FJSRL-TR-81-0001, USAF Academy, Colorado, 1981;ADA 094772.

5. J. S. Wilkes, J. A. Levisky, R. A. Wilson, and C. L. Hussey, Inorg. Chem.,2 1263 (1982).

6. L. A. King and D. W. Seegmiller, J. Chem. Eng. Data, 16, 23 (1971).

7. G. Jones and B. C. Bradshaw, J. Am. Chem. Soc., 55, 1780 (1933).

8. R. J. Gale, B. Gilbert, and R. A. Osteryoung, Inorg. Chem., 17, 2728(1978).

9. C. A. Angell, I. M. Hodge, and P. A. Cheeseman, in "Proceedings of theInternational Symposium on Molten Salts," J. P. Pemsler, J. Braunstein, K.Nobe, D. R. Morris, and N. E. Richards, Editors, p. 138, TheElectrochemical Society Softbound Proceedings Series, Princeton, NJ (1976).

10. F. H. Hurley and T. P. Weir, J. Electrochem. Soc., 98, 203 (1951).

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