DEPARTMENT OF CHEMISTRY
TEACHING LAB EXPERIMENT RISK ASSESSMENT FORM
This form must be completed jointly by the Lab Officer in charge and the Lecturer in charge. A
hardcopy of the completed form should be kept in a file together with the Project Risk
Assessment.
Name of Lecturer in Charge
Name of Lab Officer in Charge
Module / Expt No.
A/P Jaenicke Stephan
Activity being assessed:
Toh Soh Lian
CM2166/Expt. 4
Thin Layer Chromatography
Synthesis of o- and p-nitrophenol, and separation by thin layer chromatography
OH
OH
OH
.
SiO2 HNO3
OH
NO2
+
+
NO2
Known or expected hazards associated with the activity:
Hazards of reagents, solvents and known reaction products.
State each substance and the approximate amounts to be used/produced.
List of activities involved in this experiment which inevitably entail risks. The following are the
activities being use:
1)
Glass Apparatus. Refer to prepared risk assessment on Use of Glassware.
2)
Hotplate / Magnetic Stirrer and Melting Point Instrument. Refer to prepared risk
assessment on Use of Laboratory Heating Equipment.
3)
TLC plates, Disposable glass pasteur. Refer to prepared risk assessment on Use and
Disposal of "Sharps".
4)
UV Lamp. Refer to prepared risk assessment on Use of Ultra-Violet Light Sources.
5)
Electricity. Refer to prepared risk assessment on Use of Standard Electrical Equipment.
Phenol: 240mg
Toxic in contact with skin and if swallowed. Cause burns.
Nitrated Silica Gel: 1g
Activated Silica Gel: 7.5g
Avoid contact and inhalation. Target organ(s): Lungs.
* No MSDS available for this reagent. Above information is based on MSDS for Silica Gel used
for preparation.
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Methylene Chloride: about 50ml
WARNING! Cancer hazard. Causes damage to the following organs: lungs, liver, skin, central
nervous system, eye, lens or cornea.
Routes of Entry: Inhalation. Ingestion.
n-Pentane: 10ml
Danger! Extremely flammable liquid and vapour. Vapour may cause flash fire. May be fatal if
swallowed aspiration hazard. Causes damage to the following organs: lungs, respiratory tract,
skin, central nervous system, eye, lens or cornea. May be harmful to environment if released in
large amounts.
Routes of Entry: Inhalation. Ingestion.
Ethyl Acetate: 15ml
Saturated Sodium Bicarbonate Solution: 7ml
Highly flammable. Vapours may cause drowsiness and dizziness.
6M Hydrochloric solution: 0.2l.
Toxic. Causes burns. Material is extremely destructive to tissue of the mucous membranes and
upper respiratory tract, eyes, and skin. Inhalation may result in spasm, inflammation and
edema of the larynxand bronchi, chemical pneumonitis, and pulmonary edema. Symptoms of
exposure may include burning sensation, coughing, wheezing, laryngitis, shortness of breath,
headache, nausea, and vomiting.
Anhydrous Sodium Sulphate:
May be hazardous to eye, skin, inhalation and ingestion.
Purified Nitrogen
Nitrogen is colourless, odourless gas. The main health hazard associated with releases of this
gas is asphyxiation, by displacement of oxygen.
Symptoms of over-exposure by route of Exposure: The most significant route of over-exposure
for Nitrogen is by inhalation.
2-Nitrophenol: (End product)
Irritating to skin.
4-Nitrophenol: (End product)
Harmful. Danger of cumulative effects.
Incompatible materials (special precautions):
Phenol:
Reactive with oxidizing agents, acids. Avoid aluminium (heat), aldehydes, halogens, nitrites,
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nitrates, hydrogen peroxides, iron (III) compounds, salts of oxyhalogenic acids, peroxi
compounds, formaldehyde. Avoid heating.
Nitrated Silica Gel:
Activated Silica Gel:
Materials to Avoid: Strong acids, Hydrogen fluoride.
Methylene Chloride:
Incompatible Materials: Reactive with oxidizing agents, metals.
Hazardous Decomposition Products: These products are halogenated compounds.
n-Pentane:
Incompatible Materials: Highly reactive with oxidizing agents.
Hazardous Decomposition Products: Carbon oxides (CO, CO2).
Ethyl Acetate:
Conditions to be avoided: Heating.
Substances to be avoided: Alkali metals, fluorine, hydrides, strong oxidizing agents, water with
air and light, fuming sulphuric acid, lithium aluminium hydride, chlorosulfonic acid.
Further information: Highly inflammable; light-sensitive; sensitive to air; unsuitable working
materials: various plastics. Explosive with air in a vaporous/gaseous state.
Saturated Sodium Bicarbonate Solution:
Incompatible Materials: Reactive with acids. Reacts violently with ammonium phosphate,
monobasic.
6M Hydrochloric solution:
Conditions to Avoid: Do not allow water to enter container because of violent reaction.
Materials to Avoid: Bases, Amines, Alkali metals Copper, Copper alloys, Aluminium.
Hazardous Decomposition Products: Hydrogen chloride gas.
Anhydrous Sodium Sulphate:
No information available.
Purified Nitrogen
Stability: Normally stable in gaseous state.
Materials with which substance is incompatible: Titanium is the only element that will burn in
Nitrogen. Lithium reacts slowly with Nitrogen at ambient temperatures.
Conditions to avoid: Contact with incompatible materials. Cylinders exposed to high
temperatures or direct flame can rupture or burst.
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2-Nitrophenol: (End product)
Conditions to be avoided: Heating.
Substances to be avoided: Strong oxidizing agents, strong acids, strong alkalis, nitrates,
nitrites, alkali hydroxides.
Further information: Heat-sensitive.
4-Nitrophenol: (End product)
Conditions to be avoided: Strong heating.
Substances to be avoided: Alkali hydroxides, reducing agents, conc. Sulphuric acid, alkalis,
acids.
Further information: Fire-promoting substance. Explosible with air in a vaporous/gaseous state.
The risk of injury and its severity likely to arise from these hazards:
Phenol:
Inhalation: Mucosal irritations, coughing, dyspnoea, damage of respiratory tract.
Skin Contact: Burns. Danger of skin adsorption.
Eye Contact: Burns! Risk of blindness.
Swallowed: Burns in the mouth, throat, oesophagus and gastrointestinal tract.
Absorption: Headache, drowsiness, inebriation, confusion, unconsciousness, cardiovascular
disorders, changes in the blood picture, respiratory arrest and death. Damage of liver, kidneys,
heart.
Nitrated Silica Gel:
Activated Silica Gel:
Inhalation: May be harmful. Material may be irritating to mucous membranes and upper
respiratory tract.
Skin Contact: May cause irritation.
Skin Absorption: May be harmful.
Eye Contact: May cause irritation.
Ingestion: May be harmful.
Methylene Chloride:
Skin Contact: Hazardous (sensitizer, irritant). Skin inflammation is characterized by itching,
scaling, reddening, or, occasionally, blistering.
Eye Contact: Extremely hazardous (irritant). Inflammation of the eye is characterized by
redness, watering, and itching.
Inhalation: Hazardous (lung irritant).
Ingestion: Hazardous.
Aggravated by Overexposure: To a highly toxic material may produce general deterioration of
health by an accumulation in one or many human organs.
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n-Pentane:
Skin Contact: May be hazardous (irritant). Skin inflammation is characterized by itching,
scaling, reddening, or, occasionally, blistering.
Eye Contact: May be hazardous (irritant).
Inhalation: Hazardous (lung irritant).
Ingestion: Extremely hazardous. May be fatal if swallowed.
Aggravated by Overexposure: To a highly toxic material may produce general deterioration of
health by an accumulation in one or many human organs.
Ethyl Acetate:
Skin Contact: Drying-out effect resulting in rough and chapped skin.
Eye Contact: Irritations.
After Ingestion and Inhalation: Mucosal irritations, lack of appetite, headache, drowsiness.
In high concentrations: Salivation, nausea, vomiting, narcosis, respiratory paralysis.
Long-term exposure: Sensitization possible in predisposed persons.
After accidental swallowing the substance may pose a risk of aspiration. Passage into the lung
(vomiting!) can result in a condition resembling pneumonia (chemical pneumonitis).
Saturated Sodium Bicarbonate Solution:
Eye Contact: May be hazardous (irritant).
6M Hydrochloric solution:
Inhalation: Toxic. Material is extremely destructive to the tissue of the mucous membranes and
upper respiratory tract.
Skin Contact: Causes burns.
Skin Absorption: May be harmful.
Eye Contact: Causes burns.
Ingestion: May be harmful.
Anhydrous Sodium Sulphate:
Eye Contact: May be hazardous (irritant).
Skin Contact: May be hazardous (irritant). Skin inflammation is characterized by itching,
scaling, reddening, or, occasionally, blistering.
Inhalation: May be hazardous (lung irritant).
Ingestion: May be hazardous.
Purified Nitrogen
Inhalation: High concentrations of this gas can cause an oxygen-deficient environment.
Individuals breathing such an atmosphere may experience symptoms which include
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headaches, ringing in ears, dizziness, drowsiness, unconsciousness, nausea, vomiting, and
depression of all the senses. Under some circumstances of over-exposure, death may occur.
The following effects associated with various levels of oxygen are as follows:
Concentration symptom of exposure
12-16% Oxygen: Breathing and pulse rate increased, muscular coordination slightly disturbed.
10-14% Oxygen: Emotional upset, abnormal fatigue, disturbed respiration.
6-10% Oxygen: Nausea and vomiting, collapse or loss of consciousness.
Below 6%: Convulsive movements, possible respiratory collapse, and death.
Health effects or risks from exposure: ACUTE: The most significant hazards associated with
this gas are inhalation of oxygen-deficient atmospheres. Symptoms of oxygen deficiency
include respiratory difficulty, ringing in ears, headaches, shortness of breath, wheezing,
headache, dizziness, indigestion, nausea, and, at high concentrations, unconsciousness or
death may occur. The skin of a victim of over-exposure may have a blue color.
CHRONIC: There is currently no known adverse health effects associated with chronic
exposure to this gas.
TARGET ORGANS: Respiratory system.
2-Nitrophenol: (End product)
Skin Contact: Slight irritations.
4-Nitrophenol: (End product)
Skin Contact: Absorption.
Inhalation: Irritation symptoms in the respiratory tract.
Ingestion: Irritations of mucous membranes in the mouth, pharynx, oesophagus and
gastrointestinal tract. Vomiting, local irritation symptoms. Effect potentiated by: heat, ethanol.
After absorption: After a latency period: headache, tiredness, dizziness, nausea, vomiting,
methaemoglobinaemia, cyanosis, drop in blood pressure, collapse.
Systemic effects: Damage of: kidneys, liver.
Subacute to chronic toxicity: Bacterial mutagenicity: Bacillus subtilis: positive.
Who is at risk?
Persons handling the materials and as well as those present in the vicinity.
Measure to be taken to reduce the level of risk:
Proper laboratory attire and safety measures must always be used in order to reduce the level
or risk. Material should be handled or transferred in an approved fume hood or with adequate
ventilation Wash thoroughly after handling. Do not take internally. Eye wash and safety
equipment should be readily available.
Eye protection: Chemical safety goggles.
Hand protection: Gloves.
Please
refer
to
PSSO
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Safety
Information
Centre
website
on
safety
measures:
http://www.chemistry.nus.edu.sg/PSSO/Safety.htm.
Training prerequisites:
This assessment should be read by everyone who will be using the above mentioned
chemicals. Please refer to Completed Risk Assessment forms on Common Activities:
http://www.chemistry.nus.edu.sg/PSSO/Safety/Risk/risk.htm#Common.
Level of risk remaining:
Constant vigilance is required by the users.
Emergency action if :
Spill:
Phenol:
Small Spill: Use appropriate tools to put the spilled solid in a convenient waste disposal
container.
Large Spill: Stop leak if without risk. Do not get water inside container. Do not touch spilled
material. Prevent entry into sink. Eliminate all ignition sources. Call for assistance on disposal.
Nitrated Silica Gel:
Activated Silica Gel::
Procedure(s) of personal precaution(s): Exercise appropriate precautions to minimize direct
contact with skin or eyes and prevent inhalation of dust.
Methods for cleaning up: Sweep up, place in a bag and hold for waste disposal. Avoid raising
dust. Ventilate area and wash spill site after material pickup is complete.
Methylene Chloride:
Small Spill & Leak: Dilute with water and mop up, or absorb with an inert dry material and
place in an appropriate waste disposal container.
Large Spill & Leak: Stop leak if without risk. Do not touch spilled material. Use water spray to
reduce vapours. Prevent entry into sink. Eliminate all ignition sources. Call for assistance on
disposal.
n-Pentane:
Small Spill & Leak: Absorb with an inert material and put the spilled material in an appropriate
waste disposal.
Large Spill & Leak: Keep away from heat and ignition. Stop leak if without risk. Absorb with
DRY earth, sand or other non-combustible material. Do not touch spilled material. Prevent
entry into sink. Call for assistance on disposal.
Ethyl Acetate:
Do not inhale vapours/aerosols. Avoid substance contact. Ensure supply of fresh air in
enclosed rooms. Do not allow to enter sink; risk of explosion! Take up with liquid-absorbent
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material. Forward for disposal. Clean up affected area.
Saturated Sodium Bicarbonate Solution & Anhydrous Sodium Sulphate:
Small Spill & Leak: Use appropriate tools to put the spilled solid in a convenient waste disposal
container.
Large Spill & Leak: Use a shovel to put the material into a convenient waste disposal
container. Finish cleaning by spreading water on the contaminated surface and allow to
evacuate through the sanitary system.
6M Hydrochloric solution:
Procedure(s) of personal precaution(s): Chemical safety goggles, rubber boots and gloves.
Methods for cleaning up: Absorb on sand or vermiculite and place in closed containers for
disposal. Ventilate area and wash spill site after material pickup is complete.
Purified Nitrogen
Leak response: Evacuate immediate area. Uncontrolled releases should be responded to by
trained personnel using pre-planned procedures. Proper protective equipment should be used.
In case of a leak, clear the affected area, protect people, and respond with trained personnel.
Locate and seal the source of the leaking gas. Allow the gas, which is lighter than air to
dissipate. If leaking incidentally from the cylinder or its valve, contact your supplier.
2-Nitrophenol: (End product)
Avoid generation of dusts; do not inhale dusts. Ensure supply of fresh air in enclosed rooms.
Do not allow to enter sink. Take up dry. Forward for disposal. Clean up affected area.
4-Nitrophenol: (End product)
Avoid substance contact. Avoid inhalation of dusts. Ensure supply of fresh sir in enclosed
rooms. Do not allow to enter sewerage system. Take up dry. Forward for disposal. Clean up
affected area. Avoid generation of dusts.
Fire:
Phenol:
Flammable solid.
Suitable Extinguishing Media: Water, foam.
Small Fire: Use DRY chemical powder.
Large Fire: Use water spray or fog. Cool containing vessels with water jet in order to prevent
pressure build-up, auto ignition or explosion.
Nitrated Silica Gel:
Activated Silica Gel::
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Extinguishing media: Noncombustible. Use extinguishing media appropriate to surrounding fire
conditions.
Fire Fighting protective equipment: Wear self-contained breathing apparatus and protective
clothing to prevent contact with skin and eyes.
Specific Hazard(s): Emits toxic fumes under fire conditions.
Methylene Chloride:
Products of Combustion: These products are carbon oxides (CO, CO2), halogenated
compounds.
Fire fighting media: SMALL FIRE: Use DRY chemical powder. LARGE FIRE: Use water spray,
fog or foam. Do not use water jet.
Fire fighting Protective Clothing: Be sure to use an approved/certified respirator or equivalent.
n-Pentane:
Products of Combustion: These products are carbon oxides (CO, CO2).
Fire Hazards in Presence of Various Substances: Extremely flammable in presence of open
flames, sparks and static discharge, of shocks, of heat.
Fire fighting media: SMALL FIRE: Use DRY chemical powder. LARGE FIRE: Use water spray
or fog. Cool containing vessels with water jet in order to prevent pressure build-up, auto
ignition or explosion.
Ethyl Acetate:
Suitable extinguishing media: Foam, powder.
Special risks: Combustible. Vapours heavier than air. Forms explosive mixtures with air at
ambient temperatures. Development of hazardous combustion gases or vapours possible in
the event of fire.
Other information: Take measures to prevent electrostatic charging. Cool container with spray
water from a save distance. Contain escaping vapours with water.
Saturated Sodium Bicarbonate Solution:
Non flammable.
6M Hydrochloric solution:
Extinguishing media: Carbon dioxide, dry chemical powder, or appropriate foam.
Fire Fighting protective equipment: Wear self –contained breathing apparatus and protective
clothing to prevent contact with skin and eyes.
Specific Hazard(s): Emits toxic fumes under fire conditions.
Anhydrous Sodium Sulphate:
Non-flammable.
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Purified Nitrogen
Fire extinguishing materials: Non-flammable, inert gas. Use extinguishing media appropriate
for surrounding fire.
Unusual fire and explosion hazards: Nitrogen does not burn; however, containers, when
involved in fire, may rupture or burst in the heat of the fire.
2-Nitrophenol: (End product)
Suitable extinguishing media: Powder, CO2.
Special risks: Combustible. Development of hazardous combustion gases or vapours possible
in the event of fire. The following may develop in event of fire: nitrogen oxides, phenol.
Other information: Cool container with spray water from a save distance.
4-Nitrophenol: (End product)
Suitable extinguishing media: Powder, foam, spray water.
Special risks: Combustible. Development of hazardous combustion gases or vapours possible
in the event of fire. The following may develop in event of fire: nitrogen oxides.
Other information: Contain escaping vapours with water.
Is the experiment suitable for out-of-hours operation ?
Yes
No
References if any:
http://www.chemdat.de/cdrl/catalog/standard/en/ (Cat no: 822296)
http://www.sigma-aldrich-sea.com/MSDS/60/60741F.pdf
http://www.emdchemicals.com/analytics/doc/msds/msds-display.asp?materialid=B10340
http://www.emdchemicals.com/analytics/doc/msds/msds-display.asp?materialid=PX0170
http://www.chemdat.de/cdrl/catalog/standard/en/ (Cat no:109623)
http://www.emdchemicals.com/analytics/doc/msds/msds-display.asp?materialid=B10247
http://www.sigma-aldrich-sea.com/MSDS/84/84435F.pdf
http://www.emdchemicals.com/analytics/doc/msds/msds-display.asp?materialid=B10264
http://www4.us.airliquide.com/Reference_Library/Cross_Product_Information/MSDS/10070.pdf
http://www.chemdat.de/cdrl/catalog/standard/en/ (Cat no: 806790)
http://www.chemdat.de/cdrl/catalog/standard/en/ (Cat no: 820896)
Signature of Lab Officer in Charge:………………………………………………………………..
Date:…………………………
Signature of Lecturer in Charge:………… ……………………………………..
Date:… ……………………..
Prepared Risks Assessments for standard equipment and operation are with the kind permission of Dr. Ken
MacNeil, School of Chemistry, University of Bristol.
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Activity being assessed:
Note any activity to be used which entail risk (e.g. use of glass vacuum apparatus, high pressures, high
voltage, radiation, high temperatures). Give reference to any special protocols to be followed, and if
appropriate attach copies to the risk assessment form. State any additional precautions taken to minimise
risk.
Known or expected hazards associated with the activity:
FOR EACH CHEMICAL, read the MSDS and note:a) Particular hazards (e.g. highly toxic, carcinogenic, corrosive, flammable, pyrophoric, explosive, volatile,
dust hazard). Note any dangerous combinations of properties (e.g. volatile and toxic).
b) Requirements for safe handling (e.g. fume cupboard, inert atmosphere, low temperature).
c) How to dispose of residuals
 Dispose to drain, with water dilution
 Neutralise, then to drain with suitable dilution
 To flammable liquid waste receptacle
 To non-flammable liquid waste receptacle
 Keep for recovery/recycling
 Keep for special disposal later (e.g. heavy metals)
 Double bag and dispose to dry waste
 Special procedure (specify)
Incompatible materials (special precautions)
Note any dangerously incompatible materials and hazards arising from contact of any reagents and
substances used with common materials such as paper, benches, hoses, etc.
Measures to be taken to reduce the level of risk
Include hazards of previously unknown products.
Location of work – laboratory, open bench, fume cupboard
Level of risk remaining:
Likelihood and consequences of any accident or unforeseen events whilst carrying out the activity. When
this has been done, choose the appropriate procedure:a) Close supervision and/or attendance of trained first-aider needed.
b) Specific approval of supervisor needed.
c) Training is needed prior-to or during the operations specified.
d) Training is complete and only general laboratory competence required.
e) No risk perceived.
Emergency action:
a) Any special requirements to deal with accidental spillage or leakage.
b) What to do in the event of accidental exposure (skin contact, inhalation, etc.).
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