Safety in the Chemistry Laboratory

Transcription

1 Safety in the Chemistry Laboratory CHAPTER1 Safety must be everyone s primary concern in the chemistry lab. Understanding and following all safety rules in the organic chemistry lab is critical to your well-being as well as that of others in the lab room and to the protection of the environment. 1.1 PERSONAL SAFETY Dress appropriately for the lab period. Bare feet, sandals, shorts, short skirts, and halter or tank tops are not allowed in the lab room. Long hair and loose clothing should be tied back. Synthetic fingernails pose a personal fire hazard and should not be worn. Personal items, including, but not limited to, book bags and books, should be put in the area of the lab room designated for that purpose. Do not put personal items on the lab bench. Do not work alone in the lab. Safety glasses or goggles must be worn at all times when in the laboratory. The first thing you should do when you enter the lab room is to put on your safety glasses or goggles. The last thing you should do before leaving the lab room is to take them off. Inform your instructor about any health conditions that might affect your performance in the lab. This includes identifying any allergies to specific chemicals. Never smoke, eat, drink, or apply cosmetics in the lab. If you spill a chemical on your skin, wash the area well with soap and water for at least five minutes and report the incident to your instructor immediately. Make sure that you wash your hands before leaving the lab room. Never taste any substance in the lab and do not purposely smell chemicals directly unless instructed to do so. Familiarize yourself with the environment of the lab room. Know where safety equipment can be found and make sure you know how to operate the eyewash fountain and safety shower properly. In some cases, it may be important that you know how to operate a fire extinguisher. Be aware of the activities of others in the lab room. For example, do not use flames when someone else in the lab is using flammable materials. 3

2 4 Part 1 Theory and Techniques Do not perform an unscheduled or unauthorized experiment. While in the lab, concentrate on what you are doing and why you are doing it. Personal electronic equipment, including cell phones, should not be used during the laboratory period. 1.2 FIRE/EARTHQUAKE/EMERGENCY EVACUATION In the event of any emergency situation in the lab, remain calm and follow the established procedure for the situation as well as any directions from your instructor. Familiarize yourself with the location of any emergency exits in your lab room on the first day of class. Familiarize yourself with the emergency evacuation plan for your building on the first day of class. Immediately notify your instructor of any fire or other emergency in the lab. Before exiting the lab in an emergency, turn off all heat sources (sand baths, melting-point instruments, etc.) if possible. 1.3 EQUIPMENT SAFETY 68.5 DIGITAL THERMOMETER ON OFF LIGHT F/ C Use only digital thermometers to measure the temperature of a sand bath. Never use a mercury thermometer for this purpose. Only round-bottomed flasks or thick-walled filter flasks should be placed under vacuum. Erlenmeyer flasks should never be placed under vacuum. Check that glassware does not have any cracks before placing it under vacuum. Never use a Bunsen or microburner before checking to ensure that there are no flammable substances in your vicinity. Be aware that liquids with low flash points can ignite if they come in contact with a hot surface, such as a hot plate. In addition, a spark from a hot plate thermostat can ignite flammable vapors in the vicinity. For example, diethyl ether has a vapor density greater than air and can creep along a lab bench to pose a hazard far from the point of use. Never pipette by mouth. Before heating a liquid, add a new boiling stick or chip, or stir with a magnetic stirring bar. Never heat a closed system. Never distill a system to dryness. Keep your face away from the opening of a vessel when mixing reactants or when applying heat to a reaction mixture. Never vent a separatory funnel or other system that is under pressure toward yourself or another person. Assemble equipment and apparatus properly using clamps when needed. Use a suitable heating source and protect the reaction from

3 Chapter 1 Safety in the Chemistry Laboratory 5 water or air when necessary. If noxious fumes are given off during a reaction, use an appropriate trap or work in a fume hood. 1.4 CHEMICAL SAFETY MSDS RSOURCE IGHT-TO-KNOW Familiarize yourself with the properties of the chemicals you will be working with and make a table of important physical properties and hazards. The most complete information is given in the Material Safety Data Sheets (MSDS), which include the information listed below. These are available on the Internet, for example at msds/. Section 1. Section 2. Section 3. Section 4. Section 5. Section 6. Section 7. Section 8. Section 9. Section 10. Section 11. Section 12. Section 13. Section 14. Section 15. Section 16. Identifying Information Composition/Information on Ingredients Hazards Identification First Aid Measures Fire Fighting Measures (This section includes the flash point and autoignition temperature.) Accidental Release Measures Handling and Storage Exposure Controls/Personal Protection Physical and Chemical Properties Stability and Reactivity Toxicology Information Ecological Information Disposal Considerations Transport Information Regulatory Information Other Information (This section includes the National Fire Protection Association (NFPA) Ratings.) Before coming to the lab, read the experiment carefully and enter a prelab (Section 2.1) in your laboratory notebook. The prelab should include a flowchart of the procedure you will be following. Record all safety notes for the experiment in the prelab write-up in your laboratory notebook. Carefully read all labels and make sure that you use the correct solvents and reactants. Be careful to use the correct amount of each reactant. Weigh materials in a suitable container and use an appropriate vessel to dispense liquid reactants. If a chemical is spilled, notify your instructor immediately. Follow the proper method for cleaning up the chemical. Chemical spills must be cleaned up immediately. Control the rate of addition of reactants if necessary. For example, the instructions for the experiment will indicate if reactants should be added all at once, in a dilute solution, or gradually.

4 6 Part 1 Theory and Techniques The temperature of the reaction mixture should be controlled by heating or cooling to obtain a reasonable reaction rate. When instructed, the reaction should be stirred to maintain homogeneity. Check to make sure that mixing is efficient. NFPA Ratings are found on chemical containers, on trucks transporting chemicals, and in establishments where chemicals are used, such as in gas stations. It is important to know the meaning of the colored areas of the NFPA diamond and the level of the hazard indicated by the number in each area. HEALTH (BLUE) 4 Danger May be fatal on short exposure. Specialized protective equipment is required. 3 Warning Corrosive or toxic. Avoid skin contact or inhalation. 2 Warning May be harmful if inhaled or absorbed. 1 Caution May be irritating. 0 No unusual hazard FLAMMABILITY (RED) 4 Danger Flammable gas or extremely flammable liquid 3 Warning Flammable liquid, flash point below 100 F 2 Caution Combustible liquid, flash point of 100 to 200 F 1 Caution Combustible if heated 0 Not combustible REACTIVITY (YELLOW) 4 Danger Explosive material at room temperature 3 Danger May be explosive if shocked, heated under confinement, or mixed with water. 2 Warning Unstable or may react violently if mixed with water. 1 Caution May react if heated or mixed with water, but not violently. 0 Stable Not reactive when mixed with water SPECIAL NOTICE KEY (WHITE) W Water Reactive OX Oxidizing Agent Blue health Red flammability White special Yellow reactivity 1.5 CLEANUP AND WASTE DISPOSAL Observe all guidelines for the proper disposal of by-products and solvents according to laboratory rules and state law. General rules for cleanup are given at the end of each experiment. These should be included in the prelab write-up in your laboratory notebook. Minimize waste by using only the amounts of materials necessary to conduct the experiment. By sharing materials with others, such as chromatography developing chambers, the waste generated can be reduced.

5 Chapter 1 Safety in the Chemistry Laboratory 7 Before storing any compounds, put them in an appropriate container that is labeled with your name, the name of the material or the number of the experiment, and the date it was generated. Dispose of all chemicals and chemically contaminated materials in the appropriately labeled containers. Needles must be disposed of in the special containers designed for handling syringe needles. Return all chemicals to their proper place. Leave the lab bench and all common areas clean.

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