Lecture 2 Chemical
Compatibility
Chem. 601
Some things simply
should not be together!
Working with Chemicals
Lessons Learned- Hand Sanitizer
University of Hawaii
• Combining hydrogen, carbon dioxide, and oxygen gasses from high-pressure cylinders to lower
pressure tank
New pressure gauge
• Week before with similar setup, but smaller 3.8L had a small internal explosion.
Working with
Chemicals/Haz.
Gases
• Chemical Hazard Classification
• Chemical Compatibility
• Handling and Storage of
Chemicals
• Chemical Hazard Classifications
NFPA Diamond
• The NFPA Diamond is often used to
identify chemical hazards on large
vessels, small containers, and buildings.
• NFPA= National Fire Protection
Association
Blue: Health Hazard Ratings:
4- Deadly: Exposure may cause death
or major residual injury
3- Extreme Damager: Exposure could
cause serious injury even if treated
2- Hazardous: Intense or prolonged
exposure may cause incapacitation or
possible residual injury
1- Slightly Hazardous: May cause
irritation or minimal residual injury
0- Normal Material: Hazard no greater
than normal material
Red: Flammability
0 – Will not burn
1 – Considerable pre-heating required
for ignition
2 – Moderately heated
3 – Can be ignited under almost all
ambient temperature conditions
4 – Will rapidly or completely vaporize
at atmospheric pressure and
temperature or is readily dispersed in
air and will burn readily.
Yellow: Reactivity/Instability
0 – Normally stable under fire
conditions
1 – Normally stable, but can become
unstable under elevated temp./pres.
2 – Violent chemical change at
elevated temp./pres., reacts violently
with H2O.
3 – Explosive decomposition requires
a strong initiating source, must be
heated under confinement before
initiation; reacts explosively with H2O.
4 – Readily capable of detonation or
explosive decomposition at normal
temperatures & pressures.
White: Special Hazards
W – Unusual reactivity with water
OX– Possess oxidizing properties
COR-Corrosive
ALK- Alkaline
BIO- Biohazard
POI- Poison
CYL- Cylinder
CRYO- Cryogenic
RAD- Radioactive
Chemical Hazard Classification
Explosives
~ 0.00008 g AgCNO
(silver fulminate)
Other “Explosives”
Old Ethyl Ether (Peroxide-Forming)
Other “Explosives”
+ =
Peroxide Forming Chemicals
Category I Materials-
• Recommended shelf-life:
• 3- mts. whether inhibited or
uninhibited.
• Examples: Isopropyl Ether, Sodium Amide,
Vinylidene Chloride…
Category II and III Materials –
• Recommended shelf-life:
• 3-mts for uninhibited
• 12-mts for inhibited
• Examples: Tetrahydrofuran, Cyclohexene,
Ethylene Glycol…
Peroxide Forming
Example
• Berkeley Incident
• Undergraduate researcher working a Rotovap to
remove organic solvents from an azobenzene
participate.
• Adjusted flask apparatus, caused it to explode.
• Glass fragments went into face and upper torso,
hitting safety goggles and forehead.
• Received stitches above eye and other
treatments.
• Two known peroxide-forming chemicals
(tetrahydrofuran and ethyl ether) were used in
this reaction.
Gases
• Compressed
• No liquid phase
• Ex) Oxygen and Air
• Cryogenic
• Liquefied gas at low temperature
• Ex) Nitrogen and Helium
• Liquefied
• Liquid and gas in equilibrium at
ordinary temperature, under
pressure
• Ex) Chlorine and LPG)
Compressed Gasses
Cylinder Labeling: Cylinders are labeled according to chemical hazard.
Cylinder Safe Handling
• Oxygen- increased fire hazard and oxygen intoxication
• Inert Gases- risk of suffocation
• Toxic Gases- risk of poisoning
• Corrosive Gases- risk to lungs, eyes, and skin
• Flammable Gases- risk of fire and explosion
Gas Examples
• Methyl
bromide
• Sulfur
Hexafluoride
• Silane
Transportation/Safe
Handling of
Compressed Gases
Safe Handling
Procedures
• Most cylinders are
pressurized to over 2,000
PSI or nearly three million
lbs. total pressure.
• That means if the valve
stem or cylinder wall is
compromised – the
cylinder becomes a rocket
Additional Cylinder Safe Handling Rules
• Cylinders should be
securely double-strapped
to a sturdy, immovable
object.
• Cylinders should never be
emptied completely – use
down to 25 PSI. (“suck
back” danger)
• Cylinders should not be
stored near or be subject
to extreme temperatures
Additional Cylinder Safe Handling Rules
Right-hand Thread Left-hand Thread
(Reverse Thread)
Notched
Nut
• Used for flammable, toxic, or
• Used for most common gases.
corrosive gases.
• Normal thread tightens to the
• Reverse thread tightens to the left,
right, loosens to the left. loosens to the right.
(“Righty-tighty, lefty-loosey”) • Left hand threads indicated by a
notched nut.
Cryogenic Gases
• Liquid nitrogen and helium are
common
• Frostbite
• Asphyxiation
• At liquid nitrogen temperatures,
air liquefies in traps and vacuum
lines – concentrated pockets of
oxygen develop
Liquid Nitrogen
Cryogenic Gases Cont.
• Never use glass Dewars
without safety netting.
• Safety glasses, enclosed shoes and appropriate
gloving is mandatory.
• Be very careful where you use liquid cryogens
as MOST things respond differently to -196 °C
(liquid N2)
Flammable or Combustible Chemicals
Flammable or Combustible Flammable vs. Combustible Flash Point
• Combustible greater than 140 F
• Ex)
• Flammable or Combustible • Phenol
chemicals are those that evaporate • Aniline
fast enough to • Iso-octyl alcohol
generate sufficient vapor • Butyric Acid
pressure to ignite in the
presence of an ignition source.
• Flammable less than 140 F
• Ex)
• The minimum temperature at • Acetone
which this can occur is called the • Benzene
Ethanol
Flash Point. •
• Isopropyl Alcohol
Where would you find a
chemicals Flashpoint?
Alkali Metals
Oxidizers
• An oxidizing agent (also called an oxidant or oxidizer) can be
defined as either:
• A chemical compound that readily transfers oxygen atoms, or
• A substance that gains electrons in a redox chemical reaction
• “. . ate” and “per . .” in the chemical name are likely oxidizers.
Examples of Oxidizers: Potassium Permanganate, Perchloric Acid, Nitric
Acid, Hydrogen Peroxide, Nitrates
Poisons
• Every chemical is toxic to the human body given
the right amount of dosage.
• The four main routes of entry into the body are:
• Inhalation
• Absorption (through the skin or eyes)
• Ingestion
• Injection
Wii Radio Contest
Poisons Cont.
Animal LD 50 Ingested by 150 lb. Toxicity
Adult The relative acute toxicity of a chemical can
be identified by looking at it’s oral LD50. The
Up to 50 mg/kg 1 tsp or less Extremely toxic
LD50 represents the dose to laboratory
50-500 mg/kg 1 tsp to 1 oz Very toxic animals which resulted in the death of 50% of
the test population. LC50 is the lethal
500-5000 mg/kg 1 oz to 1 pt Moderately toxic concentration of a gas.
5-15 g/kg 1 pt to 1 qt Slightly toxic
Over 15 g/kg more than 1 qt Practically nontoxic
Carcinogens
• Carcinogens are chemicals capable
of causing cancer. Cancer, in the
simplest sense, is the uncontrolled
growth of cells, which can occur in
any organ.
• Carcinogens are chronically toxic
substances; that is, they cause
damage after repeated and long
duration exposures, and their effects
may become evident after a long
latency period. This makes them
particularly insidious because they
have no immediate apparent
harmful effects.
Teratogens
Some very common chemicals such as
acetonitrile, ethyl alcohol, toluene,
ethylene glycol, chloroform, and
benzene are known or suspected
teratogens.
Radioactive Material
• Ionizing radiation can be electromagnetic (X-
rays or gamma radiation) or particulate
(electrons, positrons, mesons, protons,
antiprotons, or ions).
• Almost all work with radioactive material is
governed by the Nuclear Regulatory
Commission (NRC).
• The most common types of radiation in the
laboratory include:
• Alpha- high energy particles with high mass and
very short ranges.
• Beta- an electron or positron.
• Ex’s: carbon-14, tritium, phosphorus-32
• Gamma - electromagnetic radiation emitted by
the nuclei of atoms during decay. Lead is often
used for shielding.
Corrosive Chemicals
Corrosives are
chemicals that can
cause visible
destruction of or
irreversible alterations
in living tissue by
chemical contact.
Acids and bases are
corrosives.
Chemical Compatibility
Chemical Compatibility
Chemical Compatibility
The first two principles of safe
laboratory chemical storage are:
1. Store the least amount of
each chemical possible
2. Segregate incompatible
chemicals
Chemical Compatibility
• If you don’t know if they are
compatible don’t guess…use
one of the following:
• Experts such as your Chemistry
Professor
• BYU’s Risk Management
• Compatibility Charts
Cole-Parmer
https://www.coleparmer.com/Chemical-Resistance
Chemical Handling
Chemical Handling
Chemical
Handling
Hydrofluoric Acid
• Lab Technician was performing acid digestion of oil well
core samples with 70% HF.
• Believed to be sitting, wearing two pairs of wrist length
gloves and polyvinyl chloride sleeve protectors.
• Burns to 9% of his body.
• No calcium gluconate rinsed with water for 6 min, then
swimming pool for 35-40 min.
Segregate Incompatible Chemicals
Causes of Lab “Accidents”
• Poor Housekeeping
• Improper Storage
• Container Failure
• Bypassing Engineering
Controls
• Unauthorized experiments
Coming Up…
Assignments Due Next Friday Next Weeks Lecture
• “Exam” #2 from today's lecture • PPE
• Lab Assessment (Inspection)
