Enthalpies of vaporization of aliphatic C5 and C6 alcohols

Fluid Phase Equilibria,

20 (1985) 111-118 Elsevier Science Publishers B.V., Amsterdam-Printedin The Netherlands

ENTHALPIES

V.

OF VAPORIZATION

MAJER,

V. SVOBODA,

Department

V. UCHYTILOVA

of Physical

166 28 Prague

OF ALIPHATIC

Chemistry,

111

C5 AND C6 ALCOHOLS

and M. FINKE Institute

of Chemical

Technology,

6 /Czechoslovakia/

ABSTRACT New eight

calorimetric isomers

enthalpies

of pentanol

cent. The results

were

tic Cl-C4

alcohols,

the variations

related

and OH-group

and hexanol

combined

regarding closely

of vaporization with

with

in enthalpies with

determined

an accuracy

literature

and some qualitative

properties

were

values

conclusions

of

0.3 per

for alipha-

were

of vaporization

for

drawn

and in

chain

length,

degree

contribution

methods

are increasingly

of branching,

position.

INTRODUCTION Various used

types

of group

in thermochemistry

modynamic

quantities,

and chemical including

et al.,

1979,

Lebedev

and Miroshnichenko,

enthalpy

of vaporization

are usually boiling

1983; Ducros

estimated

temperature

The determination requires est

tic alcohols studied

or some other

for which of truly

are

groups

types

among the most

experimental

important

are only available

for Cl-C4 members

With

of three

of vaporization l-alcohols

for higher

at 298.15

037%3812/85/$03.30

group

isomers aliphatic

data for the largAlthough

alipha-

frequently data

of the homologous of pentanol,

Q 1985 Elsevier Science Publishers B.V.

needed.

contributions

and most

alcohols

quantities

the normal

frequently

experimental

K, and not always with

1980;

1983/. The

related

of compounds.

sufficient

et al.,

K and/or

the data are most

of accurate

of compounds,

the exception

closely

ther-

1979; Hoshino

and Taylor,

at 298.15

representative

set of various

et al.,

1980; Ishizuka

1981; Guthrie

in this way

the knowledge

possible

et al.,

to estimate

engineering

AH v /Majer

on

AHv

series.

the enthalpies,

are only known

sufficient

for

accuracy.

112 For

the

other

and

the

indirect

via

the

sures, relate ture,

isomers

Clapeyron if

at

to

the

method

known

these

temperature

tigating

temperature

aliphatic

alcohols.

gous

isomers

2-pentanol,

nol,

below

results

a suitable results

degree

the

of

decided

to

vapour

most

normal

AH v at

whatever, pressures,

feasible:

expand

of

deliberately and

and

pres-

frequently

boiling 298.15

aHv

for a

tempera-

K by

this

equation.

available

analysis

of

branching,

data

for

One

variation

and

OH-group

of C5

and

analo-

aim

of

of this

‘%Hv for to

work

these

supplement

Another

was

to

aim

alcohols

and

with

of

combine

to make

the

comthe

parameters

nHv

C6

3-methyl-l-buta-

the

in

inves-

eight

to evaluate

Cl-C4

the

of

by

4-methyl-l-penta-

temperatures, and

data,

a group group

1-pentanol,

dependences

boiling

knowledge

1-hexanol,

2-methyl-2-pentanol.

normal

our

chose

hexanol:

temperature

correlating

of

data vapour

accuracy,

near

dependences

literature

with

litative

range

we

We

the the

with

not

2-methyl-2-butanol,

to measure

pounds

usually

sufficient

evaluation

of pentanol

2-hexanol,

was

calorimetric

impossible.

reasons,

nol,

no

0.f AH v from

is

with

a credible

entirely

For

are

equation

all

making

there

determination

chain

our a qua-

length,

position.

EXF'ERIMENTAL The vakia/

purified

under ned

compounds

reduced

were by

repeated

were

as

2-pentanol,

follows:

99.51.

was

The

which removed

samples water

content

a thermal

low

during O.C3 The

not

by means

were

kept was

with

mass

per

measurements

on a

use

of

were

for

of A3

for

determi-

ionization

detec99.95;

1-hexanol,

2-methyl-2-pentanol,

part

other

99.89;

alcoholic

significantly.

sieves, period

before

samples,

column

as

98,95;

in whose

with

starting

the water

the

content

isoWater

presence

of measurements.

chromatographically

detector all

1 m packed

98.64;

most

the

Czechoslo-

3-methyl-l-butanol,

n I1v-values

molecular

throughout checked

the

the

Brno,

purities,

a flame

99.82;

2-hexanol,

affect

conductivity them:

the

l-pentanol,

99,55;

impurities could

/Lachema

mole-percentage

2-methyl-2-butanol,

99.78;

4-methyl-1-pentanol,

mers

products

distillation

The

pressure.

chromatographically

tor,

and

commercial

use

the

the

The of

measurements was

always

be-

cent. were

zation

calorimeter

already

abling

measurements

from

made

with

described room

an

adiabatic /Majer

temperature

et to

isothermal al.,

378

1978/,

K at

vaporien-

saturated

113 vapour

pressures

from

1 to 200 kPa. The technique

controlled

withdrawal

occurring

as a result

meter

below

head

serves

its intensity.

is vaporized which

range

small,

outside

the time Three

in the and to

all of the sample

/l-2 g/

from temperatures

was near

pressures,

of results.

at each temperature.

the calori-

valve

vaporization

starting

pressures

unduly

outside

the calorimeter.

the calorimeter

vapour

on

vessel,

A throttle

equilibrium

In an experiment,

vapour

extending

reproducibility ple

to ensure

for which

at lower saturated was

the pressure

pressure.

were performed

the saturated

pressure

vapour

and condensed

The measurements

from the vaporization

of reducing

the saturated

calorimeter control

of vapour

relies

the lower

had been

at

limit of

designed

/l kPa/:

the intensity

of vaporization

of measurement

and impairing

to five runs were

The reproducibility

made

was about

for a sam-

0.15 per

cent. RESULTS

AND DISCUSSION

Experimental Table tion.

enthalpies

1 gives

average

On the basis

lysis, we believe available

temperature. sults with smoothed

values

data were

in the

data

was

from other

and parameters

and

with

of vaporizaan error

in the values

combined

literature,

The objective

enthalpies

of results

that the uncertainty our

for C5 and C6 alcohols

of measured

of reproducibility

than 0.25 per cent. values

of vaporization

is not more

calorimetric

and correlated Next,

selected

of the temperature

aHV-

as a function

to check the consistency

sources.

ana-

values

correlation

of

of our rewere

of

AH V

were

evaluated.

The purpose

of this procedure

a temperature range wider than that reveal possible systematic errors. over

The final of Wads6

ted error, measured with

error

stated

error, compound

temperature, with

the following

of Counsel1 range

/1980/

from

%/: and

et al. /1970/

as it was

high-pressure

the above

literature

for

/the sta1-pentanol

nHv-value Our values data.

measurements

and 3-methyl-l-butanol source,

closest

not our aim to extend

region.

V

and to

362 to 411 K /four points

for 1-pentanol

only a single

DH

data: measurements

and l-hexanol

0.5 B/. From the last named

to the high-pressure

sistency

of our measurements

K for 1-pentanol

of 0.1-0.2

and Lydersen

for either tion

0.3 %/; values

a stated

boiling

involved

at 298.15

over a temperature

of Radosz /the

correlation

/1966/

was to correlate

showed

Enthalpies

we included

to the normal the correlaexcellent

con-

of vaporization

114 at 298.15 K for isomeric /1963/

exhibited

therefore were

measured by McCurdy and Laidler negative deviation of about 2 PO and

were not considered.

klso excluded from the treatment of Mathews /1926/ for 3-methyl-l-butanol,

the old measurement

and a value of M&sson 0.35 % higher with our data,

TABLE

pentanols

a systematic

et al. /19'77/ for 1-hexanol

than that measured

and

which

about

is

is not consistent

either.

1

Observed

values

of enthalpies

T/K/ Name

of vaporization 313.151

298.15

328.15

343.15

358.15

368.15

51.22 49.69 46.87 41.97 55.18 53.94 50.74 46.05

45.44 40.30 53.64 52.65 49.21 44.37

AH -

l-Pentanol 3-Methyl-1-butanol 2-Pentanol 2-Methyl-2-butanol_ l-Hexanol 4-Methyl-l-pentanol 2-Hexanol 2-Methyl-2-pentanol X

by Wadsb

- value

measured

,kJ,:ol,

_ 55.21x 54.17 50.07

55.69 54.21 52.70 48.40

54.75

56.82 52.84

at temperature

54.43 52.91 50.90 46.36 5a.51 57.41 54.96 50.73

52.96 51.39 48.98

44.24 57.06 55.70 53.00 48.45

303.15 K

TABLE 2 Enthalpies

results

of vaporization,

Name

K

of correlation

a

B

/W

/kJ/mol/ 1-Pentanol 3-Methyl-1-butanol 2-Pentanol 2-Methyl-2-butanol l-Hexanol 4-Methyl-1-pentanol 2-Hexanol 2-Methyl-2-pentanol The data were al.,

AHv-

67.55 68.92 61.59 58.46 72.06 74.90 65.48 69.24

smoothed

Tc

-0.8195 -0.5980 -1.2689 -1.4989 -l.c)59o -c-7757 -1.4306 -1.;!302 with

0.8272 0.7228 1.0462 1.2301 1.0052 0.8766 1.1616 1.1694

588.2 579.4 551.6 545.0 610.0 603.5 568.2 559.5

s /J/mol/ 103 58 47 45 97 36 90 24

the aid of the equation

AT

/W 298-431 303-432 298-368 298-368 298-368 328-368 314-368 298-368 /Majer

et

19&4/

Kexp(-aTr)(l-Tr)B

/I/

115 K, a,

where ted

with

al.

was

critical

by

ranges

these

For

over

with

the

It has

ends

out

again

are

less

than

/Majer

range,

observed

of

for

temperature

et

and

al.,

We

the

range,

for

1984/

that

with

may

be

of Eqn./l/

AHv

correlation

close

that

the

proximity.

for

capable,

Cl-C4

even

This

studied

in

AH

V

behaviour

here:

the

deviations

positive

over

variation

concavity.

negative

and

columns temperatu-

assume

variant

in its

compounds

systematic

the

%.

is not

strong

2,

Ambrose

of vaporization

representing

of its

gave

valid.

C.3

redu-

in Table

two

and

sufficient

equation

the

of

other

a two-parameter is

is

forwhichestimate

The

enthalpies

1981/

because

a report

correlations

temperature

two-parameter

correlation

of the

of

et al.,

temperature

once

the

from

/1955/.

the

parameters

boiling

temperature,

rameter

of

T

r summarized

of 2-pentanol

Lydersen

compounds,

pointed

the

the

an error

normal

limited

with

of

and

are

/l/

taken

exception

parameters

organic

been

alcohols

was

which

a - fl /TekbE

below

the

method

with

most

of Eqn.

deviations,~,

smoothing

calculated

a

the

parameters,

temperatures

with

standard

adjustable

Parameters

/19&o/,

made

give re

fl are

temperature.

along et

and

at

deviations

in

two-paboth

the

middle.

Enthalpies

of vaporization

for

Cl-C6

alcohols

at

characteristic

temperatures Table 298.15 and

K

all

changes

3 gives

a summary

and

normal

the

isomers in

of

lower

AH v and

in

The

first

taken

from

the

literature

Dykyj

and

Rep&s,

1979/.

the

boiling

temperature,

zation, gas

li&d

derived

taken The

AH'

and

were

table

from

vapour

at 298.15

a compilation

needed a virial

coefficient.

K/

between for

This

thus

related

quotes

In

to

of

and

from

The

values

and

AHv

of state

coefficient

was

an overview with

the

al.,

enthalpies

of

of vapori-

Cl-C4

/to

ideal

/298.15

estimated

K/

was

after by

be

gas

of

and

saturated

estimated

the

were

published/.

and

the

ideal

alcohols

measurements,

Svoboda

vapori-

enthalpies

for

Tb,

1973;

normal

at

the

of

alcohol

temperatures,

enthalpies

truncated

alcohols

et

given

of

at

C6

Boublik

the

calorimetric

enthalpies

and

boiling

between

of Majer the

CS

vaporization

standard

/difference

for

permitting

1980;

addition

K/.

of vaporization

quantities

normal

entropies

calculating

equation

enthalpies

temperatures

/Ambrose,

Asv/T,/,

/298.15

exclusively

difference

using

column

lists

the

alcohols,

closely

structure.

zation,

of

boiling

second

method

by virial of Hayden

116 and

O_Conne11/1975/

for

Tsonopoulos

/1974/

for

no

values

were

reliable

tion

parameters

apparent for

listed

that

is

in Table

curacy

increases

with

is

for

Cl-C4

alcohols,

TABLE

it

former

from

the

isomers

to

obtained the

length

to

an must

the in

of

method

the

From

error

by

extrapolation;

of

less

1 %.

increase

in

be

into

taken

For

the

associa3 it

error

correction

the

values

0.3

here, but

values by

is

the

than

of extrapolation,

exceeci

and

that

an

case

Table

pentanol,

Vie assume

of

latter

radii

method.

negligible.

subject

by

gyration

the

thought

conversion

for

in

values

cases

the

since

almost

3 are

of

the

to

and

alcohols,

available

starting

exception

alcohols,

required

nonideality

the

Cl-C4 higher

%, with

the in

inac-

none

of

of aHv/298.15 G.2

to

0.3

K/

% due

account.

3

Enthalpies

of vaporization

at

298.15

K and

normal

boiling

temperature

AHV/Tb/

Tb /K/ l-Methanol l-Ethanol l-Propanol 2-Propanol l-Butanol 2-Methyl-l-propanol 2-Butanol 2-Methyl-2-propanol l-Pentanol 3-Methyl-1-butanol 2-Pentanol 2-Methyl-2-butanol l-Zexanol 4-Methyl-1-pentanol 2-Hexanol 2-Methyl-2-pentanol X

- value

obtained

Comparison tive

of

conclusions

ing

chain

the

primary, be

mal

boiling

not

constant:

kJ/mol,

and

in

degree

Table

its

value

3 enables

changes of

or

37.83 42.46 47.50 45.48 52.42 50.89 49.81 46.75 57.04 55.63 54.23 50.17 61.61 60.47 58.47 54.82

AHv

make

takes

higher

positive

for

and

increas-

position

This

from

qualita-

with

alcohols.

decreases

both

some

OH-group atom.

methylene-increment

in nHv/Tt,/ it

carbon

for

to

quantities

and

branchin%,

the

us

in the

tertiary

in predicting

temperature,

for nSV/Tb/

37.43 42.32 47.45 45.39 52.35 50.82 49.72 46.69 57.02 55.61x 54.21 50.10 61.61 6O.47x 58.46x 54.76

104.2 109.7 111.9 112.1 110.7 109.8 109.3 109.9 107.9 109.0 105.5 104.3 103.2 104.6 99.3 100.4

extrapolation

secondary,

helpful

35.21 38.56 41.44 39.85 43.29 41.83 40.75 39.07 44.36 44.07 41.40x 39.13x 44.45x 44.47x 41.01X 39.5gx

regarding

length,

may

data

nH;/298.15/

AHv,'298.15/

/kJ/mol/

337.8 351.5 370.4 355.4 390.9 381.1 372.7 355.5 411.2 404.2 392.4 375.0 430.7 425.0 413.1 394 -2 by

ASv/Tb/

3.5

at

information At

the

nor-

l-alcohols to

0.1

negative

is

117 values. with

The

AHv/298.15

increasing

between from

a

4.6

5.1

l-alcohol

to

re

reproducible

re.

Transition

nHv/298.15 from

chain

and

2.1

at to

I:/, kJ/mol

opposite

tendency being

tert-form, /5.7

mal

length,

the 298.15

the

is

found

of

the

a constant boiling

for

group

298.15

K do to

not

the

differ

group

greatly,

contribution

3.2

boiling with

values both

going far

mo-

temperatu-

a decrease

in

increasing

chain

for

C6 alcohols.

The

the

magnitude

the

kJ/mol. is

In

found

for

kJ/mol/.

the

reference

preferable

to

of

AH

quantitizs

and are

length

of

passing

/6.9

methods, is

on again

kJ/mol

hexanol

K/

varying

are

normal

decrease

and

/298.15 the

1.1

to

smaller

As

the

set-alcohols,

contribution

temperature

increase

quantities

tert-form

with

2.1

pentanol

temperature.

suited

at

to

with

from

or

is associated

alcohols

enhanced

in the

set-

K than

regular

methylene-increment

diminishes

C3

a fairly

Changes

iso-form

which

than

the

iso-,

a substantially

kJ/mol/

cations of

shows

kJ/mol.

for

decrease

K/

to the butanol In applilevel

that

AHo

V

at

of nor298.15

equally

approach.

REFERENCES Ambrose, D., 1980. Vapour-Liquid Critical Properties. NPL Report Chem. 107, Teddington. Boublik, T., V. Fried and E. H&la, 1973. The Vapour Pressures of Pure Substances. Elsevier, Amsterdam, 626 pp. Counsell, J.F., J-0. Fenwick and E.B. Less, 1970. J. Chem. Thermodyn. 2: 367-372. Ducros, M., J-F. Gruson and H. Sannier, 1980. Termochim. Acta 36: 39-65. Dykyj, J.,and M. Rep%, 1979. Tlak Nasytenej Pary Orqanickych Zlucenin. Veda, Bratislava, 516 pp. Guthrie, J.P.,and K.F. Taylor, 1983. Can. J. Chem. 61: 602-607. Hayden, J.G. and J.P. O*Connell, 1975. Ind. Enc. Chem., Process Des. Develop. 14: 209-216. Hoshino, D., K. Naqahama and M. Hirata, 1979. J. Jap. Petr. Inst. 22: 32-37. Hoshino, D., K. Nagahama and M. Hirata, 1983. Ind. Eng. Chem., Fundam. 22: 430-433. Ishizuka, I., E. Sarashina, J. Arai and S. Saito, 1980. J. Chem. Eng. Jap. 13: 90-97. Lebedev, Yu.A.,and E.A. Miroshnichenko, 1981. Termokhimiya ParoVeshchestv, Nauka, Moskva, obrazovaniya Organicheskikh PP. 186-203. of Critical Properties of Organic Lydersen, A., 1955. Estimation Compounds. Univ. Wisconsin, Coil. Eng., Exp. Stn. Rep. 3, Madison. Wis. Majer, V., V. Svoboda, V. Hanek and J. Pick, 1978. Collect. Czech. Commun. 43: 1313-1324. Chem. Majer, V., V. Svoboda, S. H&la and J. Pick, 1979. Collect. Czech. Chem. Commun. 44: 637-651.

Ii

118 Majer, V., V. Svoboda and V. Hynek, 1964. J. Chem. Thennodyn. in press. V. and V. Svoboda, Enthalpies of Vaporization of Crcanic Majer, Critical Review and Cata Compilation. IUPAC Project, Compounds, to be published. Msnsson, 16., P. Sellers, G. Stridh and S. Sunner, 1977. J. Chem. Thermodyn. 9: 91-97. Mathews, J.H., 1926. J. Amer. Chem. Sot. 48: 562-576. McCurdy, K-G. and X.J. Laidler, 1963. Can. J. Chem. 41: 1867-1671. Radosz, M. and A. Lydersen, 1980. Chem.-Ing.-Techn. 52: 756-757. Tek6E, V., V. Majer, V. Svoboda and V. Hynek, 1981. J. Chem. Thermodyn. 13: 659-662. Tsonopoulos, C., 1974. AIChE J. 20: 263-272. WadsG, I., 1966. Acta Chem. Stand. 2C: 544-552.