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 Principal Investigator
Name of Lab Officer in Charge
Module / Expt No.
Irene Teo
CM1121
Activity being assessed:
GRIGNARD SYSTHESIS
4: (a) Synthesis of Grignard reagent p-Tolylmagnesium Bromide
(b) Grignard Synthesis of p-Toluic Acid
Br
Br
Mg, I2
1) CO2
anhydrous ether
CH 3
COOH
2) H+ / H2O
CH 3
CH 3
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.
1. Magnesium turnings (2.05g):
Flammable, Irritant, Reacts violently with water.
2. Bromotoluene (10.5ml):
Irritating to eyes, respiratory system and skin. Combustible.
3. Diethyl ether:
Extremely flammable, toxic, harmful, may form explosive peroxides.
4. Dry-ice:
Nonflammable high-pressure liquid and gas.
5. Calcium chloride, anhydrous:
Harmful if swallowed. Irritating to eyes, respiratory system and skin. Hygroscopic
6. Iodine:
Corrosive. Dangerous for the environment. Harmful by inhalation and in contact with
skin. Causes burns. May cause sensitization by inhalation and skin contact. Very toxic
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to aquatic organisms. Severe lachrymator.
7. Hydrochloric acid, 6M (15ml):
Toxic by inhalation. Causes burns. Irritating to respiratory system.
8. Sodium hydroxide, 5%:
Corrosive, causes burns, exothermic in contact with water.
9. Ethanol (~100ml):
Highly flammable; toxic, harmful by inhalation and if swallowed. Irritating to eyes,
respiratory system and skin.
Incompatible materials (special precautions):
1. Magnesium turnings:
Exothermic in contact with water; Hazardous combustion products; Acids; Acid
chloride; Strong oxidizing reagents. React violently with: halogens; Chlorinated
solvents; Water.
2. p-Bromotoluene:
Incompatibilities with strong oxidizing agents, hazardous combustion or
decomposition products, carbon monoxide, carbon dioxide, hydrogen bromide gas.
3. Diethyl ether:
Sensitive to light, sensitive to air, sensitive to heat, oxidizing agents, strong acids,
hazardous combustion or decomposition products, carbon monoxide, carbon dioxide,
hazardous polymerization will not occur.
4. Dry ice:
Stability: Stable. Hazardous combustion or decomposition products nature of
decomposition products not known.
5. Calcium chloride:
Hygroscopic. Strong acids, boron oxides, zinc, calcium oxide, methyl vinyl ether,
calcium chloride is attacked by bromine trifluoride. Hazardous combustion or
decomposition products, hydrogen chloride gas, calcium oxide. Hazardous
polymerization will not occur.
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6. Iodine:
Rubber, Plastics, Iron And Iron Salts, Sulfur, Ammonia, Magnesium, Zinc Aluminum,
Metals, Alkalies, Antimony Salts, Arsenites, Bromides, Carbonates, Chlorides, Iodides,
Thiocyanates, Ferrous Salts, Hypophosphites, Morphine Salts, Oils, Creosote,
Phosphates, Tannic Acid, Tartrates, Vegetable Extracts. Mixing Iodine, Antimony and
ammonia resulted in an explosion. A Violent reaction occurs between iodine and
acetaldehyde. Hazardous combustion or decomposition products. Nature of c
composition products not known. Hazardous polymerization will not occur.
7. Hydrochloric acid, 6M:
Incompatibilities with bases, amines, alkali metals, copper, copper alloys, aluminum,
hazardous combustion or decomposition products, hydrogen chloride gas, hazardous
polymerization will not occur.
8. Sodium hydroxide, 5%:
Do not allow water to enter container because of violent reaction. Incompatibilities
with strong oxidizing agents, strong acids, organic materials hazardous combustion or
decomposition products, sodium/sodium oxides. Hazardous polymerization will not
occur.
9.Ethyl alcohol:
Stable: Stable. Conditions to Avoid: Protect from moisture. Materials to avoid: Alkali
metals, Ammonia, Oxidizing agents, Peroxides.
The risk of injury and its severity likely to arise from these hazards:
1. Magnesium turning:
Skin Contact: Causes skin irritation.
Skin Absorption: May be harmful if absorbed through the skin.
Eye Contact: Causes eye irritation.
Inhalation: May be harmful if inhaled. Material is irritating to mucous membranes and upper
respiratory tract.
Ingestion: May be harmful if swallowed.
2. Bromotoluene:
Inhalation: Material is irritating to mucous membranes and upper respiratory tract.
Multiple Routes: May be harmful by inhalation, ingestion, or skin absorption. Causes
eye and skin irritation.
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3. Ether:
Skin Contact: Causes skin irritation.
Skin Absorption: May be harmful if bsorbed through the skin.
Eye Contact: Causes eye irritation.
Inhalation: May be harmful if inhaled. Material is irritating to mucous membranes and upper
respiratory tract.
Ingestion: Harmful if swallowed.
4. Dry ice:
Skin Contact: Can cause severe frostbite. Causes blisters on contact with skin.
5. Calcium chloride:
Skin Contact: Causes skin irritation.
Skin Absorption: May be harmful if absorbed through the skin.
Eye Contact: Causes eye irritation.
Inhalation: Material is irritating to mucous membranes and upper respiratory tract. May be
harmful if inhaled.
Ingestion: Harmful if swallowed.
6. Iodine:
Skin Contact: Causes burns.
Skin Absorption: Harmful if absorbed through skin.
Eye Contact: Causes burns. Severe lachrymator.
Inhalation: Harmful if inhaled. Material is extremely destructive to the tissue of the mucous
membranes and upper respiratory tract.
Ingestion: May be harmful if swallowed.
7. Hydrochloric acid:
Skin Contact: Causes burns.
Skin Absorption: May be harmful if absorbed through the skin. Eye Contact: Causes burns.
Inhalation: Toxic if inhaled. Material is extremely destructive to the tissue of the mucous
membranes and upper respiratory tract.
Ingestion: May be harmful if swallowed.
8. Sod hydroxide:
Skin Contact: Causes burns.
Skin Absorption: May be harmful if absorbed through the skin.
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Eye Contact: Causes burns.
Inhalation: Material is extremely destructive to the tissue of the mucous membranes and
upper respiratory tract. May be harmful if inhaled.
Ingestion: May be harmful if swallowed.
9. Ethanol:
Skin Contact: Causes skin irritation.
Skin Absorption: May be harmful if absorbed through the skin.
Eye Contact: Causes eye irritation.
Inhalation: May be harmful if inhaled. Material is irritating to mucous membranes and upper
respiratory tract.
Ingestion: May be harmful if swallowed.
Who is at risk?
The students who do the experiments. May have an effect on all occupants.
Measure to be taken to reduce the level of risk:
1. Wear safety goggles.
2. Wear disposable hand gloves.
3. Wear lab coat.
4. Work in the fume hoods.
5. To provide safety shower and eye wash.
6. To first aid kits.
7. To provide fire extinguishers and fire blankets.
8. To provide spillage kits.
Training prerequisites:
Briefing before practical class start.
Use of Glassware
Use of Standard Electrical Equipment
Level of risk remaining:
a. Training is needed prior-to or during the operations specified.
b. Training is complete and only general laboratory competence required.
Emergency action if :

Skin contact: Immediately wash skin with soap and copious amounts of water.

Eye contact: Immediately flush eyes with copious amounts of water for at least 15
minutes.
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Spill:
1. Magnesium turning:
Avoid raising dust. Sweep up, place in a bag and hold for waste disposal. Ventilate
area and wash spill site after material pickup is complete.
2. Bromotoluene:
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.
3. Ether:
Cover with dry-lime, sand, or soda ash. Place in covered containers using non-sparking
tools and transport outdoors. Ventilate area and wash spill site after material pickup is
complete.
4. Dry ice:
Place in appropriate container.
5. Calcium chloride:
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.
6. Iodine:
Sweep up, place in a bag and hold for waste disposal. Ventilate area and wash spill
site after material pickup is complete.
7. Hydrochloric acid:
Absorb on sand or vermiculite and place in closed containers for disposal. Ventilate
area and wash spill site after material pickup is complete.
8. Sod hydroxide:
Absorb on sand or vermiculite and place in closed containers for disposal. Ventilate
area and wash spill site after material pickup is complete.
9. Ethanol:
Cover with dry-lime, sand, or soda ash. Place in covered containers using
non-sparking tools and transport outdoors. Ventilate area and wash spill site after
material pickup is complete.
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Fire:
Depending on the scale of fire, use appropriate fire-extinguishing measure.
1. Magnesium turning:
Suitable: Use approved class D extinguishers or smother with dry sand, dry ground
limestone, or dry clay. Unsuitable: Do not use water, foam, or carbon dioxide.
2. Bromotoluene:
Suitable: Water spray. Carbon dioxide, dry chemical powder, or appropriate foam.
3. Ether:
Suitable: Carbon dioxide, dry chemical powder, or appropriate foam. Water may be
ineffective.
4. Dry ice:
Suitable: Use extinguishing media appropriate to surrounding fire conditions.
5. Calcium chloride:
Suitable: Noncombustible. Use extinguishing media appropriate to surrounding fire
conditions.
6. Iodine:
No data was given.
7. Hydrochloric acid:
Suitable: Carbon dioxide, dry chemical powder, or appropriate foam. Unsuitable: Do
not use water.
8. Sod hydroxide:
Suitable: Dry chemical powder. Unsuitable: Do not use water.
9. Ethanol:
Suitable: Water spray. Carbon dioxide, dry chemical powder, or appropriate foam.
Is the experiment suitable for out-of-hours operation ?
Yes
No
References if any:
Signature of Lab Officer in Charge::………………………………………………………………..
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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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