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MALCOLM M. RENFREW Un~versltyof Idaho MOSCOW, Idaho 83843
Safety Practice in the Undergraduate Organic Chemistry Laboiatory Stanley Wawzonek The University of lowa, lowa City, lowa 52242 The enactment of the Iowa Tort Claims Act (Chapter 25A of the 1973 Code of Iowa) which allows claims to he filed against the State of Iowa on account of damage to, or lass of orooertv or oersonal iniurv or death caused
resulted in a greater emphasis upon the safety practices in the undergraduate Organic Chemistry laboratory course. This one-semester course requires 6 hours of laboratory and one lecture per week and is taken by premed and predent students, pharmacists, chemistry majors, chemical engineers and others. The enrollment in the spring semester is usually above 200 students. The laboratory part is taught in sections of 24 students or less by a graduate teaching assistant. These individuals are instructed a t the beeinnine of the semester to hecome inlead to incidents which would result in injuries to the students. Toemphasize the importance of avoiding such incidents it is pointed out that the lowa Tort Claims Act applies to all employeesof the State including the faculty, staff and graduate students on appointment or any other individual, including students, acting in a temporary or permanent capacity on behalf of the University. Since the scientific interests of the students taking the course vary, the following steps were taken to make the laboratory work as safe as possible. Safety precautions are included in bold face type with each experiment even though they may he constantly repeated during the semester. The effect of inorganic reagents such as concentrated sulfuric acid, sodium hydroxide etc. on skin is pointed out and the treatment required for such chemicals is eiven. Other orecautions mentioned are
safety precautions involved and may be quizzed on these before doing the experiment. An illustration of the safety precautions used in the oreoaration of cumene and npropylbenzene from benzene and n-propyl chloride is shown.
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Stanley Wawzonek, Professor of Chemistry a t The University of lowa, received his BS degree from Brown University in 1935 and his PhD from The University of Minnesota in 1939. After a year as a pmt-doctorate fellow a t The University of Minnesota and one w a r as a National Research
before joining The University of Iowa faculty in 1944. Dr. Wawzonek is active in research and has published 177 papers. He is also a ca-author of a lshoratory manual in Organic Chemistry. He received The Iowa Award of The American Chemical Society in 19fi0, The Midwest Award in 1976 and the Outstanding Achievement Award of The University of Minnesota in 1975. He is a member of Sigma Xi, Phi Lambda Upsilon, Alpha Chi Sigma, American Chemical Society and Iowa Academy of Science. He was President of the Iowa Academy of Science in 1971-72.
At the present time he is on the Editorial Board of Organic Preparations and Procedure and is an Electroorganic Divisional Editor of the Journal of the Electrochemical Society.
Safety Precautions 1) All theglasswareused in the reaction mus
be dry. 2) Aluminum chloride is a strong Lewis acid
If contact is made with your hands, was1 with large volumes of water. 3) Add pieces of clay plate before refluxin) the mixture. 4) Cool the reaction mixture before it i' added to the 6N hydrochloric wid. 5) Vent your separatory funnel during thl washing with water. 6 ) Benzene, cumene and n-propylhenzenl are extremely inflammable. Observe al precautions given under distillation (Ex oeriment 31.
. . Volume 55,Number 2, February 1978 1 A71
Safety
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Glasstuhing isawidedin the construction of labwaror) ~ - t u p ssinre it ha* h e n r r spunsible in thr pest for many mridenta involving cuts and punctures. Polypropylene tubing (6 mm OD) is an adequate substitute and its use in this manner has been described in this Journal. (F. W. Wassmundt, J. CHEM. EDUC., 53,669 (1976). This tubing can he bent very easily using a heat gun (200-300°F). The use of kits containing standard tapered equipment in place of ordinary glassware avoids incidents which occurred formerly in putting bored rubber stoppers or corks an condensers and dropping funnels. The insertion of thermometers and porcelain funnels into bored rubber stoppers remains as a source of incidents in the lahoratory. The number of these, however, is kept to a minimum by giving instructions on using lubricants and protecting hands with towels in this operation. Electrical devices (Mel-Temp) are used for the determination of melting points; liquid baths which are potentially hazardous are thus avoided. To reduce fires in the laboratory, dichloromethane (methylene chloride) has been suhstituted for diethyl ether in experiments requiring extractions. Dichloromethane (b.p. 39.8") is nonflammable and isless solublein water than ethyl ether; the solubility in water a t 25O is 1.30%in contrast to 6.04% far ethyl ether. The solubility of water in dichloromethane is 0.2% and in ether 1.47%.
A74 1 Journal of ChemicalEducation
Dichloromethane is the least toxic of the four chlorinated methanes and has recently been found not t o produce cancer in rats. This observation is based on a twa-year inhalation study with rats by toxicologists a t Dow Chemical Co. The permitted level of exposure is currently 500 ppm. Ethyl ether is used in the laboratory only for the preparation of a Grignard reagent and t o demonstrate its use as a solvent for eottonseed oil. No flames are allowed in the Inhorawr). d u r i n ~the performnnreof the fimt rxperimmt. In the rerand rxpmment the intlammabilitv
