Densities of Aromatic Hydrocarbons (Landolt-Bornstein, Numerical Data and Functional Relationships in Science and Technology , Vol 8)

354 Pages·1998·1.73 MB·English

by  R.C. Wilhoit

Landolt-Börnstein
Numerical Data and Functional Relationships in Science and Technology
New Series / Editor in Chief: W. Martienssen
Group IV: Physical Chemistry
Volume 8
Thermodynamic Properties
of Organic Compounds
and their Mixtures
Subvolume E
Densities of Aromatic Hydrocarbons
R.C. Wilhoit, X. Hong, M. Frenkel, K.R. Hall
Edited by K.R. Hall and K.N. Marsh
12 3
Editors
K.R. Hall
Thermodynamics Research Center
TheTexas A&M University System
College Station, Texas 77843-3111, USA
K.N. Marsh
former
Thermodynamics Research Center
TheTexas A&M University System
College Station, Texas 77843-3111, USA
now
University of Christchurch
New Zealand
Authors
R.C. Wilhoit
X. Hong
M. Frenkel
K.R. Hall
Thermodynamics Research Center
TheTexas A&M University System
College Station, Texas 77843-3111, USA
Preface
Critically evaluated experimental data covering the densities of organic compounds is essential for
both scientific and industrial applications. Knowledge of densities is important in many areas, including
custody transfer of materials, product specification, development of various predictive methods, and for
characterizing compounds and estimating their purity.
Various compilations of densities for organic compounds have been published. The early Landolt-
Börnstein compilation [23-ano] contained recommended values at specific temperatures. International
Critical Tables [28-ano-1] provided recommended densities at 0 (cid:176) C and values of constants for either a
second or third order polynomial equation to represent densities as a function of temperature. This
compilation also gave the range of validity of the equation and the limits of uncertainty, references used in
the evaluation and those not considered. This compilation is one of the most comprehensive ever
published. Timmermans [50-tim, 65-tim], Dreisbach [55-dre, 59-dre, 61-dre] and Landolt-Börnstein
[71-ano] published additional compilations, primarily of experimental data. These compilations contained
experimental data along with reference sources but no estimates of uncertainty for the data nor
recommended values.
The Thermodynamics Research Center has published recommended values for the densities of organic
compounds since 1942 in its two loose leaf publications: TRC Thermodynamic Tables - Hydrocarbons
and Non-Hydrocarbons. These compilations are updated with four supplements per year. References to
the literature values used in the selection and those not used in the selection appear in the references for
each table. The accuracy of the values ia apparent from the number of significant figures provided. More
recently, the Design Institute of Physical Property Data, Project 801 has assembled a set of recommended
equations for the densities of over 1500 compounds [89-dau/dan, 91-dau/dan, 92-dau/dan, 93-dau/dan,
94-dau/dan, 95-dau/dan, 96-dau/dan, 97-dau/dan]. Densities are represented by an equation fit to selected
values from the freezing temperature to the critical temperature. References to sources of data used in the
evaluation and those not used are given along with a quality assessment. In many cases, the equation does
not fit density values at intermediate temperatures, especially at 293.15 K and 298.15 K, within the
experimental uncertainty. Thus, the equation is not useful for purity comparisons, custody transfer, or
product specification when the highest accuracy is required. Smith and Srivastava [86-smi/sri, 86-smi/sri-
1] recently have published a compilation (in two volumes) which contains recommended values in tabular
form as well as equations with statistical information regarding the fit. However, this compilation contains
no indication of data quality or uncertainties.
The present volume contains densities for monocyclic aromatic hydrocarbons including alkylbenzenes,
alkenylbenzenes, alkynylbenzenes, alkadienylbenzenes, dialkenylbenzenes, alkatrienylbenzenes,
alkatetraenylbenzenes, and other related compounds which have been collected from the literature
published from 1870 to early 1997. The various compilations listed above also have been consulted for
sources of original data. This volume continues our effort in evaluation of the densities of organic
compounds [see volume IV/8B (96-wil/mar) for the densities of alkanes, volume IV/8C (96-wil/mar-1) for
the densities of alkenes, alkynes and alkadienes, and volume IV/8D (97-wil/hon) for the densities of
monocyclic non-aromatic hydrocarbons]. All experimental density values have been evaluated critically
and assigned numerical uncertainties individually. These assessments have been used to derive an
equation to fit the data and to obtain recommended values with uncertainties. Detailed evaluation
procedures appear in Chapter 1. Algorithms for the automatic selection of data used in the fit and for the
selection of the type of equation and order of polynomial have been developed. The algorithms depend
upon the assigned uncertainties, the distribution of density values over the experimental temperature
range, and the magnitude and distribution of differences between observed and smoothed values. These
algorithms can fit any kind of data to a function of independent variables. We have collected data for
674 compounds, consisting of data sets drawn from 1137 sources.
The volume contains six chapters; a list of references, and two indexes (Chemical Abstracts Service
Registry Number Index and Chemical Name Index). Chapter 1 contains: a short introduction; a
description of the tables; a detailed description of the methods used in the evaluation, selection and
smoothing process; a glossary of symbols and a description of the nomenclature used. Chapter 2 covers
the alkylbenzenes, Chapter 3 contains the alkenylbenzenes, Chapter 4 has the alkynylbenzenes,
alkadienylbenzenes, and dialkenylbenznes, Chapter 5 provides the unsaturated alkylbenzenes of general
formula C H , and Chapter 6 presents the unsaturated alkylbenzenes of general formula C H . The
n 2n-12 n 2n-14
tables contain the original literature data along with their estimated uncertainties and the evaluated data in
both numerical form and as coefficients to equations with selected statistical information. When data
cover a sufficient temperature range, graphical plots of the deviations of the experimental data from the
recommended equation are given. The chemical name index contains the IUPAC names for the
compounds, as well as alternate names that often appear in practice.
This volume should be useful to a wide community of researchers, data specialists, and engineers
working in the field of physical and organic chemistry, chemical engineering, material science,
environmental chemistry, chemical aspects of energy technology, and those engaged in the development
of new predictive procedures. The book should also be of use to students and faculty in Chemistry and
Chemical Engineering departments at universities as a reference book of evaluated thermophysical
properties.
College Station, April 1998 The Editors
Acknowledgments
The authors wish to express their sincere appreciation to staff members of the Thermodynamics
Research Center (TRC), part of the Chemical Engineering Division of the Texas Engineering Experiment
Station in The Texas A&M University System. Our special thanks to Manuf Chasmawala, Cheryl Clark,
Yong Lee, Brad Chin, and James Requenez for their assistance in data collection and entry, formatting the
text, preparing the graphs, and composing the camera-ready copy of the manuscript.
College Station, April 1998 R. C. Wilhoit, X. Hong, M. Frenkel, K. R. Hall
References
23-ano Landolt-Börnstein Physikalisch-Chemische Tabellen, Hauptwerk, Vol. 1, Roth,
W.A., Scheel, K. (eds.), Springer-Verlag: Berlin (1923).
28-ano-1 International Critical Tables of Numerical Data, Physics, Chemistry and Technology
Vol. III, Washburn, E. W. (ed.), McGraw-Hill: New York (1928).
50-tim Timmermans, J.; Physico-Chemical Constants of Pure Organic Compounds, Vol. 1,
Elsevier: New York (1950).
55-dre Dreisbach, R. R.; Physical Properties of Chemical Compounds, Advances in
Chemistry Series No. 15, Am. Chem. Soc.: Washington, D. C. (1955).
59-dre Dreisbach, R. R.; Physical Properties of Chemical Compounds - II, Advances in
Chemistry Series No. 22, Am. Chem. Soc.: Washington, D. C. (1959).
61-dre Dreisbach, R. R.; Physical Properties of Chemical Compounds, Advances in
Chemistry Series No. 29, Am. Chem. Soc.: Washington, D.C. (1961).
65-tim Timmermans, J.; Physico-Chemical Constants of Pure Organic Compounds, Vol. II,
Elsevier: New York (1965).
71-ano Landolt-Börnstein Sechste Auflage, II Band, Eigenschaften der Materie in ihren
Aggregatzuständen, 1 Teil, Mechanisch-thermische Zustandsgrössen. Springer-
Verlag: Berlin (1971).
86-smi/sri Smith, B. D.; Srivastava, R.; Thermodynamic Data for Pure Compounds, Part B.
Halogenated Hydrocarbons and Alcohols, Elsevier: New York (1986).
86-smi/sri-1 Smith, B. D.; Srivastava, R.; Thermodynamic Data for Pure Compounds, Part A.
Hydrocarbons and Ketones, Elsevier: New York (1986).
89-dau/dan Daubert, T. E.; Danner, R. P.; Physical and Thermodynamic Properties of Pure
Chemicals: Data Compilation. Taylor & Francis: London (1989).
91-dau/dan Daubert, T. E.; Danner, R. P.; Physical and Thermodynamic Properties of Pure
Chemicals: Data Compilation, Supplement 1. Taylor & Francis: London(1991).
92-dau/dan Daubert, T. E.; Danner, R. P.; Physical and Thermodynamic Properties of Pure
Chemicals: Data Compilation, Supplement 2. Taylor & Francis: London (1992).
93-dau/dan Daubert, T. E.; Danner, R. P.; Physical and Thermodynamic Properties of Pure
Chemicals: Data Compilation, Supplement 3. Taylor & Francis: London (1993).
94-dau/dan Daubert, T. E.; Danner, R. P.; Physical and Thermodynamic Properties of Pure
Chemicals: Data Compilation, Supplement 4. Taylor & Francis: London (1994).
95-dau/dan Daubert, T. E.; Danner, R. P.; Physical and Thermodynamic Properties of Pure
Chemicals: Data Compilation, Supplement 5. Taylor & Francis: London (1995).
96-dau/dan Daubert, T. E.; Danner, R. P.; Physical and Thermodynamic Properties of Pure
Chemicals: Data Compilation, Supplement 6. Taylor & Francis: London (1996).
96-wil/mar Wilhoit, R. C.; Marsh, K. N.; Hong, X.; Gadalla, N.; Frenkel, M.: Densities of
Aliphatic Hydrocarbons: Alkanes.
Landolt-Börnstein, New Series, Vol. IV/8B, Springer-Verlag: Berlin (1996).
96-wil/mar-1 Wilhoit, R. C.; Marsh, K. N.; Hong, X.; Gadalla, N.; Frenkel, M.: Densities of
Aliphatic Hydrocarbons: Alkenes, Alkadienes, Alkynes and Miscellaneous
Compounds.
Landolt-Börnstein, New Series, Vol. IV/8C, Springer-Verlag: Berlin (1996).
97-dau/dan Daubert, T. E.; Danner, R. P.; Physical and Thermodynamic Properties of Pure
Chemicals: Data Compilation, Supplement 7. Taylor & Francis: London (1997).
97-wil/hon Wilhoit, R. C.; Hong, X.; Frenkel, M.; Hall, K. R.: Densities of Monocyclic
Hydrocarbons.
Landolt-Börnstein, New Series, Vol. IV/8D, Springer-Verlag: Berlin (1997).
1.1 Basic Concepts 1
1 Introduction
1.1 Basic Concepts
The mass density of a substance is an intensive quantity defined by:
r =m/v (1.1)
where m is the mass and v is the volume of the sample. Both these quantities are extensive quantities.
Other densities often referred to in the literature are the relative density and the molar density. Relative
density, also called specific gravity, is:
r =r r / (1.2)
r 0
where r is the density of a standard substance. It is necessary to specify the conditions of temperature and
0
pressure for the standard substance. The most common reference material is water often at the temperature
of its maximum density, 4 (cid:176) C, at atmospheric pressure. The molar density is defined as
r =1/V (1.3)
m
where V is the volume occupied by one mole of the substance. The only densities reported in this volume
are the mass densities; relative and molar densities have been converted to mass densities, and all densities
have been reported in SI units. If the mass, m, in equation (1.1) has not been corrected for air bouancy it
gives the apparent density in air. The API specific gravity is: r (API) = 141.5/r – 131.5, in which r is
r r
r (288.68 K)/r o (288.68 K), and the standard substance is water at 288.68 K (60 (cid:176) F).
The density of a material is a function of temperature and pressure but its value at some standard
condition (for example, 293.15 K or 298.15 K at either atmospheric pressure or at the vapor pressure of
the compound) often is used to characterize a compound and to ascertain its purity. Accurate density
measurements as a function of temperature are important for custody transfer of materials when the
volume of the material transferred at a specific temperature is known but contracts specify the mass of
material transferred. Engineering applications utilize the density of a substance widely, frequently for the
efficient design and safe operation of chemical plants and equipment. The density and the vapor pressure
are the most often-quoted properties of a substance, and the properties most often required for prediction
of other properties of the substance. In this volume, we do not report the density of gases, but rather the
densities of solids as a function of temperature at atmospheric pressure and the densities of liquids either
at atmospheric pressure or along the saturation line up to the critical temperature.
The purpose of this compilation is to tabulate the densities of compounds, hence only minimal
description of experimental methods used to measure the density of liquids or solids appears. Detailed
descriptions of methods for density determination of solids, liquids and gases, along with appropriate
density reference standards, appear in a chapter by Davis and Koch in Physical Methods of Chemistry,
Volume VI, Determination of Thermodynamic Properties [86-ros/bae].
The two principal experimental apparatuses used to determine the density of a liquid are: the
pycnometer and the vibrating tube densimeter. The pycnometer method involves measuring the mass of a
liquid in a vessel of known volume. The volume of the pycnometer, either at the temperature of
measurement or at some reference temperature, is determined using a density standard, usually water or
mercury. Using considerable care and a precision analytical balance accurate to – 10-5 g, it is possible to
achieve densities accurate to a few parts in 106 with a pycnometer having a volume of 25 cm3 to 50 cm3.
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New Series IV/8E
2 1.1 Basic Concepts - 1.2 Scope of the Compilation
It is common to achieve accuracies of 1 part in 105 in using equation (1.1) with pycnometers as small as
5 cm3 and routine measurements can achieve 1 part in 104. However the main sources of error in assigning
density to a particular compound in a particular state arise from factors other than the measurment of mass
and volume. See Section 1.4.1
The vibrating tube densimeter relies upon the fact that the frequency f of vibration for a U or V shaped
tube depends upon the mass of material in the tube:
r = A/ f2+B (1.4)
Calibration of the apparatus is necessary; usually water and air or nitrogen are the reference materials.
Vibrating tube densimeters designed to operate close to atmospheric pressure can achieve repeatability of
parts in 106. If the reciprocal of the frequency is linear in density, accuracies of 1 part in 105 are readily
achievable.
The principal experimental method used to measure the density of a solid is determination of the mass
of liquid displaced by a known mass of solid. It is essential that the solid have no appreciable solubility in
the liquid, that all occluded air be removed from the solid and that the density of the displacement fluid be
less than that of the solid lest the solid float. Densities of crystalline solids also can be determined from
the dimensions of the unit cell. Davis and Koch discuss other methods for measuring the density of liquids
and solids such as: hydrostatic weighing of a buoy and flotation methods.
1.2 Scope of the Compilation
Volume IV/8E presents observed values for the densities of hydrocarbons containing one benzene
ring, many of which are important industrial compounds. These values represent a compilation and
evaluation of data from the scientific literature covering approximately the past 100 years. The values
presented come from the TRC Source Database. The Thermodynamics Research Center has assembled
these data over a period of years and has used them to provide the evaluated density values listed in the
TRC Thermodynamic Tables - Hydrocarbons. An additional literature search has been performed
immediately before producing this compilation to locate new or missing data and to bring the collection
up-to-date. This compilation should include at least 90% of the pertinent data reported in the literature.
The usual experimental conditions are in contact with air at one atmosphere below the normal boiling
point of the hydrocarbon, and in equilibrium with the vapor phase above the normal boiling point. In the
summary tables, temperatures reported on the Kelvin scale have been obtained by adding 273.15 to
temperatures originally given on the Celsius scale.
Densities have units of kilograms per cubic meter (kg(cid:215)m-3). Values reported in units of grams per
milliliter, where the liter is “the volume of one kilogram of water at its temperature of maximum density”
convert to kg(cid:215)m-3 when multiplied by 999.972 (as defined by the 12th General Conference of the
International Committee on Weights and Measure, 1964). Values of specific gravity relative to water at a
stated reference temperature become density upon multiplication by the accepted density of water at the
reference temperature. Most reported densities for liquids below the boiling point apply to the air-
saturated liquid.
Compounds are identified by an IUPAC approved name [93-ano-1], the empirical molecular formula,
and the Chemical Abstracts Service Registry Number. A summary table is available for each compound
which includes the reported temperature and density values, an assigned uncertainty for the density, the
difference between the observed and smoothed density values and an index key to the source of the data.
A complete list of references, identified by the index keys, appears at the end of the volume.
Where appropriate, tables of smoothed, recommended values are given at integral multiples of 10 K
over the experimental range of temperatures. Values at 293.15 K and 298.15 K are included when they are
in the range of the original data set. The recommended values also have assigned uncertainties.
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1.3 Description of Tables - 1.4 Evaluation, Selection, and Smoothing of Data 3
1.3 Description of Data Tables
Data for a particular compound are selected, evaluated and smoothed in one of four ways, depending
upon the number and accuracy of the reported values and upon their distribution over the temperature
range.
Case 1. When the data set consists of at least four acceptable, effectively distinct values (see
section 1.5.3), the densities in selected subsets are fit to a function of temperature using the least
squares criterion. A summary table for the selected set gives the densities, their estimated
uncertainties, the deviations between observed and calculated values, an index key to the list of
references and a plotting symbol. If sufficient space remains, some data outside the selected set
also are included in the summary table along with reference keys to any remaining data. A plot of
the deviations between observed and calculated values is shown for the selected subset. Error bars
indicate the size of the estimated uncertainties for the data. Distinct plotting symbols identify the
five data sources that have the smallest average estimated uncertainties. A single symbol represents
all remaining data in the selected set. A table consisting of smoothed, recommended values
(calculated from the fitted functions) is also given. Estimated uncertainties are given for the
recommended values which also appear as a continuous line on the deviation plot. Densities of
crystal phases are in a separate section of the table. In most cases, these densities have not been fit
as a function of temperature. Values of parameters, statistical measures of the fit, and references to
sources of critical constants appear at the beginning of these sections.
Case 2. For data sets that do not meet the criteria of Case 1, but contain acceptable values over a
temperature range of at least two degrees, the results are smoothed using a linear function of
temperature with an estimated coefficient of thermal expansion. A table of smoothed recommended
values is presented.
Case 3. For data sets that do not meet the criteria of either Case 1 or 2 but contain two or more
values at a single temperature, a recommended value is given for this temperature by taking a
weighted average of the observed values.
Case 4. For data sets that contain only single values at one or two temperatures, the reported values are
given rather than recommended values.
1.4 Evaluation, Selection and Smoothing of Data
1.4.1 Assignment of Uncertainties
The Thermodynamics Research Center staff have assigned an uncertainty value to each observed and
recommended density value listed in the tables. The true value of the property has a 95% probability of
being in the range covered by + or - the uncertainty about the reported value. Assignment of uncertainty is
a subjective evaluation based upon what is known about the measurement when the value is entered into
the database, and includes the effects of all sources of experimental error. The errors have been
propagated to the listed density at the reported temperature. Uncertainties reported by the investigators are
considered but not necessarily adopted. Often, investigators report repeatability, but they usually do not
provide uncertainty.
Errors in density result from errors in temperature measurement or control; calibration of instruments;
transfer, handling and weighing of samples; and impurities in the samples. At temperatures well below the
critical temperature and near room temperature, standard techniques easily achieve accuracies of – 0.05%.
For the compounds in this compilation, that level corresponds to about – 0.4 kg(cid:215)m-3. Under these
conditions, errors in temperature are not very significant. This level of accuracy only requires
Landolt-Börnstein
New Series IV/8E
4 1.4 Evaluation, Selection, and Smoothing of Data
temperatures to be known within – 0.5 K. At temperatures approaching the critical temperature,
measurements become more demanding because of the rapid increase in the magnitude of the coefficient
of thermal expansion. Greater accuracy, in general, requires careful attention to calibration, mass
determination and sample handling techniques. It is assumed that values obtained by pycnometers have
been corrected for buoyancy of air, unless the author specifically says otherwise. This correction increases
the apparent density by 0.05 - 0.1%. When this correction has not been made, the estimated uncertainty is
greater.
Most measurements of densities of liquids below their normal boiling points are made in the presence
of air. Densities reported here refer to liquids in equilibrium with a gas phase consisting of a mixture or air
and vapor at a total pressure of one atmosphere below the normal boiling point and of vapor at the
equilibrium vapor pressure above the boiling point. Thus air is not regarded as an impurity. The effect of
dissolved air and other gases on the densities of liquid hydrocarbons has been reported by Ashcroft and
Ben Isa [97-ash/ben]. The differences they observed between the density of a liquid saturated with air at
1 atm and 298.15 K and the air free liquid are shown in Table 1.
Table 1. Difference between densities of liquids saturated with air at 1 atm and 298.15 K and air free
liquids at the same temperature
Compound r (air sat.) -r (air free) Compound r (air sat.) -r (air free)
kg(cid:215)m-3 kg(cid:215)m-3
Heptane -0.089 Tetradecane -0.054
Octane -0.081 Hexadecane -0.047
Nonane -0.072 Cyclohexane -0.068
Decane -0.067 Methylcyclohexane -0.077
Dodecane -0.059 Toluene -0.062
A major source of error in most measurements is the presence of impurities in the sample. The effect
of an impurity depends upon its amount in the sample and upon the difference between its density and the
density of the principal constituent. Even when the sample purity is provided quantitatively, the impurities
often are not identified individually. Nevertheless, a report of sample purity reduces the estimated
uncertainty because it can be taken as evidence that the investigator has considered sample purity. The
most ubiquitous impurity in liquids is water, and, because its density differs significantly from those of
hydrocarbons, it is a common source of error. Exclusion of water requires that the sample be protected
from the atmosphere during transfer, and that special precautions be taken to remove the sample from
containers.
The principal source of high purity samples from 1952 to 1960 was the American Petroleum Institute
Research Project 6 at Carnegie-Mellon University. These samples were distributed to researchers through
the API Project 44 from Carnegie-Mellon University and Texas A&M University. Phillips Petroleum Co.
also supplied high purity samples, but they ceased doing so. Samples for 300 compounds from API
Project 42 are available from the Thermodynamics Research Center, along with limited supplies of
samples for compounds from API Project 6.
1.4.2 Quantitative Effect of Impurity on Density of Liquids
The molar volume of a mixture of components, V, in terms of the mole fractions x and partial molar
i
volumes of the components V is:
i
V =(cid:229) c xV (1.5)
i i
i=1
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