Math 225-spring-2012

HOW TO FIND PHYSICAL AND THERMODYNAMIC PROPERTIES OF CHEMICAL SUBSTANCES Bruce Slutsky NJIT Library

Aim of this Tutorial
The aim of this tutorial is to show you how to use electronic and traditional print resources to find thermodynamic and physical property data from a wide variety of print and electronic sources.

The Importance of Physical and Thermodynamic Property Data
Physical and thermodynamic property data are of value to chemists in academia and industry. Chemists often need this data to identify substances they have synthesized or isolated from a biological or environmental sample.

The engineering design of process equipment often requires knowledge of properties such as heat capacity, enthalpy, density, viscosity, and thermal conductivity.

Physical property for chemicals especially little-studied substances may be very difficult to find while data for common substances is likely available from several sources. Values may conflict.

Flow of Scientific Information
Scientists and engineers conceive ideas and perform experiments in the laboratory. They want to make the results of their research public. .
The published information flows from the top of the chart to the bottom. Students needing information must start their research at the bottom of the chart. Tertiary literature such as handbooks,data compilations encyclopedias, and textbooks must be consulted first. If the desired information is not found there, the researcher must try to find information in reviews, journals and conference proceedings. Such publications are indexed in subject specific databases.

Flow of Scientific Information

Data Compilations
A data compilation , in print or electronic format, extracts selected pieces of information from the journal literature. They are usually limited to type of compound ( i.e. organic, inorganic) or type of property (i.e. thermodynamic, spectral).

Data Compilations
A searcher may have to use several data compilations to find the desired information. On the other hand information on common substances may be found in several sources. Values may conflict.

Data Compilations
No single data compilation can contain all published information on the over 50 million unique chemical substances that have been reported in the literature.

Characteristics of Data Compilations
Limited number of substances covered
Limited by type of compound
Selected properties only
Available in electronic and/or print formats
Critically evaluated? (Values may differ)

Suggested Readings Problems in Physical Property Data Retrieval Donald T. Hawkins Journal of Chemical Information and Computer Sciences 1980 20 (3), 143-145 Although this paper is 30 years old, many of the points made are still valid Wagner, A. Ben. "Finding Physical Properties of Chemicals: A Practical Guide for Scientists, Engineers, and Librarians." Science & Technology Libraries 21, no. 3/4 (August 2001): 27-45. PDFs of these 2 papers will be available through Moodle

Some Print Data Compilations
CRC Handbook of Chemistry and Physics (Ready Ref QD65 .C4)
NIST-JANAF Thermochemical Tables (Ref QD511 .N57 1998)
International Critical Tables (Ref Q199 .N32)
Thermodynamic Properties of Individual Substances (Ref QD504 .T43713 1989)

Some Printed Data Compilation
Thermochemical Data of Organic Compounds (Ref QD511.8 .P43 1986)
Lange's Handbook (Ready Ref QD65 .L36 1999)
Merck Index (Ready Ref RS51 .M4 2001)
Perry's Chemical Engineer's Handbook (Circ Desk TP151 .P45 1997)

Scifinder Scholar
Electronic Version of Chemical Abstracts (1907 to the present)
It contains many links to full-text articles
Searchable by chemical substance , reaction, research topic, author or affiliation
Some physical property data is available
It is accessible from a web site.

Scifinder Scholar to find Physical Property Data
You can search under compound name or Registry Number
Some physical property data will be listed
Some links to the original journal article with the data will be given

Chemical Abstract Service Registry Number
CAS registry numbers are unique numerical identifiers for chemical elements, compounds, polymers, biological sequences, mixtures and alloys
It is easier to search for a substance under the CAS registry number since a substance can have many names
CAS Registry numbers are used in data compilations

Class Exercise Using Scifinder Find the density of cyclohexanone at 20 degrees C. Note that the densities at various temperatures are found there,

CRC Handbook of Chemistry and Physics
The most heavily used source of physical property data. It is revised annually and also includes mathematical tables, nomenclature rules, symbols, and terminology. Physical property data is limited to the compounds most frequently encountered in the laboratory, the workplace and the environment. There is an electronic version (not at NJIT)

CRC Handbook of Chemistry and Physics
MOLECULAR WEIGHT
COLOR
CRYSTALLINE FORM
BOILING POINT
MELTING POINT
DENSITY
INDEX OF REFRACTION
ENTHALPY OF FORMATION
GIBBS FREE ENERGY
ENTROPY
HEAT CAPACITY
ENTHALPY OF FUSION
IONIZATION POTENTIAL
SOLUBILITY

Class Exercise Using the CRC Handbook of Chemistry and Physics Find the density of cyclohexanone at 20 degrees C. Is the value the same as found in Scifinder?

Sources of Physical Property Data and Basic Information about Chemical Substances
http://researchguides.njit.edu/physical_properties
We will later examine some of these sites to see how to find physical property data

Index to Physical, Chemical and Other Property Data - Arizona State University
Very often we need a physical property of a substance but don't where to look for it. This index provided by Arizona State University can be very helpful. There is a link to this from http://researchguides.njit.edu/physical_properties .
As an example, we need information on the dielectric constant for several substances. We obviously start by clicking on "D". We will retrieve a list of resources that give dielectric constants.

Thermodex
Thermodex , an index of selected thermodynamic handbooks , was created and is maintained by the Maillet Chemistry Library of the University of Texas at Austin. It contains records for printed and web-based compilations of thermochemical and thermophysical data for chemical compounds and other substances.

Thermodex
You can select one or more compound types and link them to one or more property terms, and ThermoDex will return a list of handbooks that might contain this data. You must select the property and the type of property that you are seeking. .

Class Exercise Using Thermodex Find sources were you may find the heat capacities of hydrocarbons. Once you have found answers from this database, you must check the NJIT catalog to see if our library has these sources

NIST Chemistry Webbook
NIST , National Institute of Standards and Technology, is a non-regulatory federal agency within the U.S. Department of Commerce. Its mission is to develop and promote measurement, standards, and technology to enhance productivity, facilitate trade, and improve the quality of life. The NIST Chemistry WebBook contains:

NIST Chemistry Webbook
Thermochemical data for over 7000 organic and small inorganic compounds:
Enthalpy of formation
Enthalpy of combustion
Heat capacity
Entropy
Phase transition enthalpies and temperatures
Vapor pressure
Reaction thermochemistry data for over 8000 reactions.
Enthalpy of reaction

NIST CHEMISTRY WEBBOOK
Free energy of reaction
IR spectra for over 16,000 compounds.
Mass spectra for over 15,000 compounds.
UV/Vis spectra for over 1600 compounds.
Electronic and vibrational spectra for over 4500 compounds.
Constants of diatomic molecules (spectroscopic data) for over 600 compounds.
Ion energetics data for over 16,000 compounds
Thermophysical property data for 74 fluids

Searching the NIST Chemistry Webbook
Let us search for gas phase thermodynamic data on bromoform. There are several search options for this database. We will search on the name of the substance.

Chemspider
ChemSpider links together compound information across the web, providing free text and structure search access of millions of chemical structures.
It is owned by the Royal Society of Chemistry (UK) who states that it is the richest source of structure-based information

Class Exercise Using Chemspider Find the CAS Registry Number and density of ethylene glycol

Materials Safety Data Sheets (MSDS)
A Material Safety Data Sheet (MSDS) is designed to provide both workers and emergency personnel with the proper procedures for handling or working with a particular substance. MSDS's include information such as physical data
Links to sources with MSDS may be found at http://www.ilpi.com/msds/index.html#Internet

Other Sources of Property Data
Sigma-Aldrich Catalog (note –many chemical companies have online catalogs that provide physical property data)
Chemicalland21
Chemical Elements.com
Chemblink
Knovel – NJIT has access to a small sample database, but AICHE student members have access

Advantages and Disadvantages of the Wikipedia
Advantages:
Good for obtaining background knowledge on a topic
Articles can be revised and edited quickly. Information about recent events will appear there
Disadvantages:
Does not undergo the peer review process
Anyone can write or edit an article anonymously
Suggestion: Do not cite it in your bibliography

Is Wikipedia a Reliable Source of Physical Property Data?
For Benzene the following properties were found in the Wikipedia:
Density
Melting Point
Boiling Point
Solubility in Water
Please find these values and then check other sources (print or electronic) and see if the values match

Mobile Computing Apps
ChemMobi – a free app for the iPhone from Symyx Inc.
Chemspider – use your mobile browser to go to http://cs.m.chemspider.com
Periodical Table of the Elements
List of chemistry related resources for the iPhone and/or iPad

Summary of This Tutorial
In the physical chemistry laboratory at NJIT you will do experiments to find physical properties of chemical substances. These experiments were originally done years ago and reported in the literature. You must find these values and compare them with the results of your experiments. As you advance in your academic career and if you eventually work in an industrial laboratory you will likely need to find physical property data

Points to Remember
Original research including the first reporting of physical properties is published in journals and conference proceedings and eventually will appear in review articles, monographs, and textbooks. This information may be found in these sources, but much it is much easier to obtain them through print or electronic data compilations.

Points to Remember
There are over 50 million unique chemical substances that have been reported in the literature. It is much easier to find data on common substances. The overwhelming majority of all chemical substances have been reported in the literature only once or twice. Thus, many properties for those substances have not been documented in the literature

Points to Remember
It is quite possible to find the same property data in several sources. The values may differ. A good data compilation will provide a reference to the original literature where the original experiment which yielded the data is documented.

Points to Remember
You may have to search several sources to find the desired property information. Very often a data compilation will have information on the property of interest, but not for the compound of interest to you.
Material Safety Data Sheets are often a good source for property data.
There are useful indexes to physical and thermochemical data from Arizona State University , University of Texas at Austin , and Vanderbilt University .
Bruce Slutsky, Technical Reference Librarian at NJIT, has compiled a list of electronic sources at http://researchguides.njit.edu/physical_properties

Contact Me
Bruce Slutsky
Robert Van Houten Library
[email_address]
973-642-4950

Math 225-spring-2012

by Bruce Slutsky

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