Laboratory experiments for an introductory course in organic chemistry

Publication Date: April 1939. Cite this:J. Chem. Educ. 16, 4, XXX-XXX. Note: In lieu of an abstract, this is the article's first page. Click to increa...
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LABORATORY EXPERIMENTS for an INTRODUCTORY COURSE in ORGANIC CHEMISTRY NICHOLAS D. CHERONIS Chicago City Colleges, Chicago, Illinois

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H E chief objective in the introductory course of ration. This is followed by a systematic study, which organic chemistry is the selection of pertinent shows both general group properties and reactions, and facts and the arrangement of these in such a also differences in reactivity. A few experiments are manner as to develop and illustrate the fundamental camed out as typical preparations, primarily with the principles of the carbon compounds. There are great objective to teach technic and to obtain a good yield; obstacles, however, in the attainment of this objective. however, most preparation work involves small quantiThere is a bewildering accumulation of facts with refer- ties, and this has led to the development of simple apence to organic compounds, with but few correlated paratus for the separation, distillation, and refluxing of general principles. As a result, the beginner is con- small amounts of material^.^ The number of comfused in attempting to wade through the relations be- pounds tested in a particular group is quite large and tween the vast number of carbon compounds. There has been selected from substances which are available is no guiding principle such as the Periodic Table, which a t a low cost, or which can be prepared easily. In this the student finds so helpful in the study of inorganic connection, it should be mentioned that a large number chemistry. The study for the beginner becomes an of organic compounds which were rare a number of array of formulas, preparations, and reactions of one years ago are common articles today, and can be used group of compounds after another. advantageously in teaching. The laboratory work in the introductory course conA permanent part of this course is the provision for sists largely of experiments in which the sole object is demonstration experiments performed by the instructor to attempt one preparation aiter another. Occasionally, once a week during the regular laboratory period. These a few tests are given a t the end of the preparation to supplement, rather than replace, the work of the stuillustrate characteristic reactions which are often geu- dent. Demonstration experiments illustrating the aldol era1 properties of the group to which the particular condensation, the numerous applications of the Grigcompound belongs. In recent years there has been a nard reagent, the use of benzenesulfonyl chloride for the tendency to devote between one-fourth and one-fifth separation of the amines, and so forth, have been found of the semester's work to the development of skills extremely helpful by students who would otherwise and technics such as distillation, determination of melt- have had only a blackboard knowledge of the reaction. ing points, crystallization, extraction, and so forth. Further, the student gradually becomes acquainted Aside from this innovation, the laboratory work of the with more involved technic and apparatus than he introductory course has hardly changed for the past would meet through his work alone. twenty-five years. The first part of the laboratory work includes exIn a previous paper,' the author presented a series periments on the courses of organic compounds, their of experiments adapted to an introductory course to purification by crystallization and distillation. This inshow both general group properties and reactions as cludes the usual determination of the melting point, well as difference in reactivity. and the microdetermination of the boiling point, folThe present paper is a further elaboration of a lowed by the identification of elements in carbon comlaboratory course in organic chemistry, one of whose pounds. An experiment on the molecular structure of objectives is to bring out the relations among the vari- carbon compounds, using diethyl ether and butanol, ous carbon compounds rather than to teach prepara- serves as an introduction to the study of isomerism. tions alone. The plan followed in the course is the ar- After this there is a unit on hydrocarbons. rangement of the compounds of carbon into groups The student has had thus far a study of the carbon which show related properties. The preparation of atom with reference to the periodicsystem, followed by a one or two compounds in each group serves to illustrate review of the structure of matter from the modem point the principles involved in the general methods of prepa- of view, ionic and uon-ionic compounds, and a classi1 C~snoms,N. D., "Reactivity experiments for an intro' CAERONIS. N. D., "The use of semi-micro technic in eleductory course in organic chemistry," J. CKEM.EDUC., 1 4 480 mentary organic chemistry." i6id.. 16, 2&34 (1939). (1937).

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fication of organic com~oundsbased on the stage - of oxidation of the carbon atom. This serves as a preview of the 6rst part of the course. The following table illustrates the principle of classification of organic compounds according to reaction properties which can be related to structure, arranged according to the stage of oxidation of the carbon atom. The assumption back of this classification is a deliberate attempt to give the student a related comprehensive view of the simpler groups of organic compounds.

THE STUDY O F HYDROCARBONS

The hydrocarbons are regarded as parent substances from which other groups are derived. The laboratory work on the unit on hydrocarbons is shown in the following table. TABLE 2 OR

EXPBBMENTS ON HYDBOCA~BONS

Obj@iv~ o j Ihc Ezperimcnl

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Reduction of an R-X* by the use of the Gtignard reagent (* X halogen) 2.

wilrtz-Fitfig reaction

3. Remoaal of earboryl

Union of two radicals when two monohalogens are reduced under anhydrous conditions Test-tube experiment, with calcium aeetate and raldum benzoate Removal of water from aleoholo. D i f f e n s e in ease of dehydration between secondary and tertiary aleaholr

5.

Acetylene

Brief study of properties

6.

Benzene

Btid study of pmperries

7. Reaction of hydrocarbons

R-X R-OH R-NH1

R-CHX? R-CHO R-CO

R-CX

Study sod eontreat of reaction properties of: penfane, iropentane, pentene, bcaane, cyc1oherane, cycloherene (cyclohcxadiene), benzene. toluene. naohthalene: their reaction toward: squeo& 0.04 per cent. neutral permansanate. bromine in carbon tetrachloride, nitric arid. sulfvtie acid; action of molecular bromine .a saturated hydrocarbons

The preparation of n-butane by the use of the Grig-

R-COOH

nard reagent is a demonstration and illustrates the preparation of a pure hydrocarbon. It also introduces the student to a simple reaction which later will be In the above classification, the in methane shown to be to the preparation Of Other or any other hydrocarbon is considered totally reduced, FouPs of organic com~ounds. In addition, it is a good and that of completely oxidized. As- demonstration of a little more complex apparatus such suming that each of the four hydrogen atoms is at- as the three-necked flask, mercury seal stirrer, and the tachEd by a pair of electrons, the reD,acement of a hv. extraordinary cleanliness and care involved in the exdrogen atom-by another group whi;h is more negati& penment. The study of the preparation of a hydrocarbon by the than hydrogen will be considered a partial oxidation of Wurtz-Fittig reaction involves the union of two orthe carbon atom. Similarly, where two hydrogens are replaced, as in the aldehyde, by oxygen, this is considered ganic radicals when two monohalogens are reduced unas belonging to the second stage of oxidation. The der anhydrous conditions. Either the preparation of third stage includes the carboxyl group, and further n-hexane from n-propyl bromide or the preparation oxidation will cause rupture of the carbon-to-carbon of ethyl benzene from bromobenzene and ethyl bromide bond with formation of carbon dioxide. It is admitted is used. The latter gives better results. The yield obthat this classification is by no means free from diffi- tained by students varies between forty and fifty per culties, but the advantages obtained for the beginner cent. of the theory. The removal of the carboxyl illustrates the difficulty more than justify its use. In this presentation, the usual separation into aliphatic of reduction of this group to the hydrocarbon, or, for and aromatic compounds is avoided. For instance, all that matter, to any other group. The removal of the monohalogen derivatives of the hydrocarbons are con- carboxyl is explained as an oxidation-reduction of two. sidered in one m o u ~ . If we write RX, where X is a adjacent carbon atoms: H halogen, for the formula of the organic monoNaOH+R-C-H+Na2COs R-CHsCOONa halide, it is possible to treat, first, all reactions which -I FH are common to the mouohalides, and then to show bow the radical R influencesthe rate of reaction of the comreduced oxidized pound. For instance, the hydrolysis of monohalides to give hydroxy derivatives or the ammonolysis to give The unsaturated hydrocarbons are. introduced by amines are common to all. The lower alkyls react means of amylene and cyclohwtene. Amylene is easily faster than the higher ones, while those with aryl prepared in small quantities by mixing concentrated radicals require temperatures above 150°C. for any ap- sulfuric acid and tert.-butanol. The layer of amylene preciable reaction. separates on top and can be separated by means of the

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separatory tube shown in Figure 18 of the article on semimicro technic. The choice of cyclohexene as an .experiment*to study further the preparation of unsaturated hydrocarbons lies chiefly in its relation to benzene. TABLE 3

drocarbons; aliphatic, cyclic saturated, unsaturated, and aromatic. (6) It shows differencein reactivities of various members of the same group. (6) A better introduction and correlation is shown between the benzenoid and non-benzenoid hydrocarbons. THE MONOHALIDES

In the study of monohalides, which in this course follows the study of the hydrocarbons, a number of experiments are used which illustrate the general methods of preparation and their principles; and also their characteristic reactions. The experiments which are listed in Table 4 are used in the study of this unit. TABLE 4

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H H Cyclohexadiene Cyclohexatriene (benzene)

The student learns that i t is possible, by stepwise removal of hydrogen, to change cyclohexane to cyclohexene, cyclohexadiene, and cyclohexatriene, which is benzene. Cyclohexene exhibits the characteristic reactions of unsaturated hydrocarbons; cyclohexadiene exhibits these reactions to a greater degree. It would follow, then, that benzene should show an extraordinary reactivity and instability. In the experiment on the reactions of hydrocarbons, the student tests the behavior of about 0.5 g. of ten hydrocarbons to various reagents so as to contrast the properties of the various groups. For instance, the action of bromine in carbon tetrachloride differentiates the saturated from the olefins. Upon exposing to light those tubes which do not discolor immediately, halogenation by substitution may be shown. The action of neutral permanganate confirms this differentiation, and in addition it shows the greater reactivity of naphthalene as compared to benzene. The relation of benzene to other six-carbon hydrocarbons is revealed in this study. The reactions of cyclohexene and cyclohexadiene with bromine and potassium permanganate are instantaneous, while with nitric acid and sulfuric acid, explosive reactions occur. Yet benzene exhibits a stability characteristic of saturated structures. Later, various theories will be presented which propose to account for the stability acquired when another double bond is introduced. This experiment completes the study of hydrocarbons. Although the unit is rather long, it has been found that the student acquires a better understanding of the field than with the orthodox presentation. The following advantages are thounht to be derived: (a) 1Fgives a clear picture of the main groups of hy-

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'CHERONIS, N. D., "The use of semimicro technic in elementary organic chemistry," I. CHEM.EDUC., 16, 28 (1939).

The butyl chlorides and bromides

Demonstration on the hromination 01 benzene Preparation of n-butyl bromide Reactions of monohalides

Application of the law of mass action to. R--OH HX S R-X f HOH Di5erence3 in rate at which cauilibrium is reached between primary, secondary, and tertiary butanols Halogenation of hydrocarbons. D ~ ~ ~ S S of halogenation catalysts Preparation for yield

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Rate of hydrol~risof chlorides: n-butyl, sac.-butyl, 1~1.-butyl,n-amyl.eycloheryl, phenyl, beowl, and n a ~ h t h r l ( b ) Ammonolysi. of n-amyl bromide, ini.. amyl bromide, and methyl iodide. Formation of =mine. and quaternary salt. Side reactions in ammonolyri~ (4 Action of alcoholic KOH on chlorides: n-amyl.IcrI.-amyl, cydohexyl, benzyl,and phenyl. Conditions for removal of HX. Olefina ( d ) Ether formation: R-X R-ONa + R-0--R NaX (0)

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The preparation of the alkyl halides by the reaction of the monohydroxy alcohols with aqueous hydrogen halide3.4.5can be easily illustrated by test-tube experiments. The general formula for the formation is written: R 4 H

+ HX * R-X + HOH

Application of the law of mass action indicates the use of excess of the acid and of a catalyst if the attainment of equilibrium is slow. The use of primary, secondary, and tertiary butanols illustrates further the relative ease of reaction of the primary, secondary, and tertiary alcohols. With 5 cc. of alcohol and 10-12 cc. of concentrated hydrochloric or hydrobromic acid, the tertiary halide separates immediately. The secondary and primary do not show appreciable reaction and after addition of zinc chloride the tubes are heated in a water bath. The separation of small amounts of the halides formed in the tests is accomplished by the use of the separatory tube. Purification by distillation is also possible by the use of very simple micro-distilling apparatus described.

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L AND~STREIGRT, Trans. Roy. Soc. Can., [3], 23, Sect. 3.

77 (1929).

N o m s , "Organic Syntheses," Coll. Vol. 1. 1932, p. 137. KAMMAND MARVEL, I. Am. Chem. Sac., 42, 299 (1920).

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The formation of halides by the direct halogenation of hydrocarbons is illustrated by a demonstration of bromination of benzene. Halogenation of hydrocarbons in general is discussed, including the use of catalysts, methods of introducing the chlorine or bromine, and products formed. The experiment on the preparation of n-butyl bromideBis performed by the student, with the main objective of obtaining a good yield. In the course of this experiment it is possible to check whether the stndent has acquired the skill of setting up apparatus, and so forth. The experiment on the reactions of monohalides is designed to illustrate a number of general reactions, such as hydrolysis, ammonolysis, removal of halogen acid and reaction with alcoholates to form ethers. It is also possible to show differences in the reactivities of the various groups of halides. The discussion of hydrolysis is again taken up as an application of the law of mass action to the general reaction : R--OH HX R-X HOH

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NHs

[:I

+ RX + RNH

X

From this complex or salt, HX can be removed to give the amine. Further reaction yields secondary, tertiary, and finally the quaternary compound. The difference between the ammonolysis of primary and tertiary amyl bromides illustrates the ease with which the tertiary halides undergo removal of halogen acid to give unsaturated compounds. It also illustrates the general principle that in any reaction of organic compounds there are many competing equilibria involved, and often the conditions chosen do not lead to the desired product. The action of alcoholic alkalies for the removal of halogen acid and production of unsaturated compounds is a classical reaction found in all elementary textbooks of organic chemistry. Reference to the extensive literature8 on this topic discloses that ether formation may also take place. The tests to illustrate this reaction have been designed to show these differences. Alcoholic potassium hydroxide is added to n-amyl, tert.-amyl, cyclohexyl, benzyl, and phenyl chlorides. The extent of the reactions is shown by the amount of sodium chloride which separates. Addition of water separates the product which can be tested for olefin by removing a few drops. Benzyl chloride reacts rapidly but gives no oleiin, as there is no alpha hydrogen. The halogen attached directly to the phenyl group does not react. Tert.-amyl and cyclohexyl halides give olefins,while the primary halide gives almost exclusively ether. This reaction can be further illustrated as described in the experimental part. The student, i t is hoped, obtains a first-hand knowledge of some of the general reactions of the halogen group, and, in addition, acquaintance with the differences in reactivities in metathetical reactions between primary, secondary, and tertiary, as well as between alkyl and aryl compounds. The student was not able to effect removal of the halogen attached directly to the phenyl group. He may be asked then to state the conditions under which either hydrolysis or ammonolysis of such compounds is possible. The reaction is a general one; only the rate differs, depending on the nature of the radical attached to the functional group.

In the preceding experiment on the formation of the halides, the student was interested in the shift of equilibrium to the right; in this case he is interested in shifting the equilibrium to the left. The hydrolysis of n-butyl, sec.-butyl, te7t.-hntyl, n-amyl, cyclohexyl, phenyl, benzyl, and naphthyl chlorides has been described in a previous paper.' The rate is appreciable in the tertiary alkyl as compared to the primary alkyl, and the latter is faster when compared to halides in which R is a cyclic group. The ammonolysis of the monohalides is a reaction which has not been used for laboratory experiments, due to the fact that mixtures are formed, and the reaction in the aqueous system is slow a t ordinary temperatures. Using alcoholic ammonia, it is possible to illustrate adequately the formation of quaternary compounds, the formation of mixtures of amines in the ammonolysis of primary halides, and, above all, olefins in the case of tertiary. When a small amount of methyl iodide is added to excess (4 moles) of satnrated ammonia solution in ninety per cent. methanol, tetramethyl ammonium iodide separates within two to four minutes. The anatemam com~oundis saved for the work on amines - --- - --&hen the &ateAary base is prepared by the student by I. Reduction of a Monohalide to the Hydrocarbon by addition of silver hydroxide. This reaction introduces the the mode of reaction of compoundsof the general formula Use of the Grignard Rewnt.-The preparation of the R~ with ammonia, The student is fami,iar with n-butyl magnesium bromide is made according to the -standard m e t h ~ d . The ~ amounts of the reagents used the reaction of HCl and HI with ammonia: are 2.7 g. of magnesium, 20 g. of n-butyl bromide and 65 cc. of dry ether. After 2 1 the magnesium has reHX iT%4 acted, the top of the condenser is connected, first, with 'NEP, Ann., 309, 126 (1899); BvrL~aox,Bn., 3,422 (1870); In a similar manner, the monohalides react with amWISLICENWS. TALBOT, AND HENZB, Ann., 313, 237 (1900); mania, first forming compounds which the halide adds BAYER, ibid., 278,94 (1894); WAGNERAND S A ~ Z B;bid., Y , 175, 373 (1875); Lucns AND MOYSE, J. Am. Chem. Soc.. 47. 1461 to the molecule of ammonia: (1925). "Organic Syntheses," Coll. Vol. 1, 1932, p. 26. $Gnaam, ZOELLNER, ALND DICKBY. J. Am. Chem. Soc., 51, ' CAERONIS, N. D., J. CAEM.EDUC., 14, 480 (1937). 1579 (1929); "Organic Syntheses." Coll. Vol. I. 1932, p. 182. ~

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The cyclohexene is separated from the distillate by the addition of salt and removed by means of the separatory funnel, dried with a small amount of calcium chloride, and fractionated. The fraction which boils a t 80-82' is cyclohexene. V. Reactions of Hydrocarbons.-For demonstration, the action of 0.1 per cent. alkaline permanganate a t the boiling point of the hydrocarbon, on n-hexane, cyclohexane, and benzene may be set up. For the following tests, unless otherwise specified, 0.5 cc. (or 0.4 g. of solid) is used. The materials for dispensing are placed in bottles provided with droppers. Eight to ten drops are used in each test. I . Oxidation with Aqueous Permangunate.-Add to each of ten test-tubes 5 cc. of 0.04 per cent. potassium permanganate solution and 0.5 cc. of five per cent. sodium carbonate solution and place in each the proper amount of one of the hydrocarbons. The last tube serves as control to compare the color. Observe any fading after one, ten, and thirty minutes. Write the equations for any reaction which takes place. Name the products. Prepare nine test-tubes 2. Action of Bromine.-(a) fitted with corks. Place in each the proper amount of hydrocarbon and 2 cc. of two per cent. bromine solution in carbon tetrachloride. Shake occasionally and observe any change immediately after addition. Place in the dark for five minutes, then examine again. Compare the color of each tube with the control. (b) For this test, use only n-hexaue, cyclohexane, benzene, and naphthalene. Place 1cc. of the hydrocarbon, one drop of bromine (CAUTION) and a very small piece of iron wire in a test-tube. Place the tubes in a water bath a t 60°C. in the hood. Observe after ten minutes. Blow across the mouth of the test-tube, to detect hydrogen bromide, then add 5 cc. of water. 3. Action of Nitric Acid.-Add to each of ten testtubes the proper amount of hydrocarbon and 1 cc. of a mixture of concentrated nitric acid and sulfuric acid. (CAUTION.Use the hood and when adding acid to unsaturated hydrocarbons, step back after addition of the acid.) Place the mixture that did not react immediately in a bath a t 40-50°C. for fifteen minutes, then add contents to 25 cc. of water. Note any evidence of nitration. 4. Action of Sulfuric Acid-(a) To each of ten test-tubes add the proper amount of hydrocarbon and 1cc. of concentrated sulfuric acid. Shake and note whether the hydrocarbon has dissolved. Allow to stand for five minutes and then examine again. Pour the contents into 10 cc. of water. (b) Use only n-hexane, cyclohexane, and henzene. Repeat the above, using fuming sulfuric acid (CAUTION). Allow to stand for fifteen minutes, then pour in 20 cc. of water, and note whether the product is soluble. (6) In a test-tube, shake 1cc. of cyclohexenewith 1cc. of seventy per cent. sulfuric acid, cooling the mixture until i t is homogeneous. Add 2 cc. of water and note 10 W m ~ z Ann., , (iii), 44, 275 (1855); FImo A m KONIG, the layer of alcohol that separates out. ibid., 144, 277 (1867); &id., 149, 324 (1869): SCHORLEMMER, I . The Butyl Chlorides and Bromides: 1. Chloibid., 144. 184 (1867);ibid.. 161, 277 (1872).

a dry bottle or a U-tube immersed in an ice mixture, then with a washing bottle containing sulfuric acid, and then to an empty bottle leading to a pneumatic trough arranged for the collection of gas by displacement. The reaction flask is placed in a small pail of ice water, and water containing dilute hydrochloric acid is added through the separatory funnel, drop by drop, so that a constant stream of gas is obtained. Several bottles are collected, and the usual tests are made, i. e., combustibility, action of bromine water, and aqueous 0.04 per cent. potassium permanganate. II. Wurtz-Fittig Reaction.l0-Ethyl benzene is prepared by the well-known method. In practice, 20 g. of bromobenzene, 17.3 g. of ethyl bromide and 40 cc. of dry ether and 9 g. of freshly cut sodium are allowed to react in a flask provided with a reflux. At the next laboratory period, the sodium bromide and nnreacted sodium are filtered through glass wool, the ether evaporated, and the residue fractionated. Yield of 45-65 per cent. is usually obtained by the students. III. Prefiaration of Hydrocarbons by Remmal of Carboxy1.-Methane and henzene are obtained by heating of sodium acetate and benzoate, respectively, with soda lime. Five g. of the salt and 2 g. of the alkali are ground in a mortar, then heated in an ignition tube. Methane is collected by water displacement. Benzene is collected in a test-tube immersed in cold water. IV. 1. Amylene (2-methyl-butene-2).-Add a few drops of tert.-amyl alcohol to 2 cc. of bromine water, shake, and note if there is any immediate decolorization. Place 5 cc. of the alcohol in a test-tube, immerse in a beaker of cold water and add carefuUy 1 cc. of concentrated sulfuric acid. Rotate the tube so as to mix the contents. After a minute, add another cc. of the acid. Rotate the tube as before. Take the tube out and allow to stand for a few minutes. Note the layer that separates on top. By means of a pipet remove small portions and test with bromine water and potassium permanganate solution. If semimicro equipment is available, the amylene layer is removed by means of the separatory tube and then distilled. For the practical preparation of amylene, fifty per cent. sulfuric acid is used to avoid the formation of polymers (sludge). The chief product is 2-methyl-b~tene-2. What other unsaturated hydrocarbons are produced? Consider the action of sulfuric acid on secondary and primary amyl alcohols and write the possible products. 2. Cyc1ohexene.-In a 500-cc. distilling flask are placed 50 cc. of cyclohexanol and 8 cc. of concentrated sulfuric acid. The flask is connected to a condenser attached to a well-cooled receiver. The distilling flask is provided with a thermometer which reaches to the bottom of the flask. Heat is applied until the temperature reaches 130' and the reaction mixture is maintained a t that temperature only until the end of distillation.

rides.- In each of three large test-tubes, place 12 cc. of concentrated hydrochloric acid. To the fkst add 5 g. of n-butyl alcohol, to the second 5 g. of secondary butyl alcohol, and to the third 5 g. of tertiary butyl alcohol. Shake a t intervals for five minutes. If a halide has been formed, i t will form a separate layer. Separate the lower layer of those mixtures which have reacted by means of a separatory tube. Add 15 g. of zinc chloride to the mixtures that did not react and heat them on a water bath for one hour, after iirst providing them with corks through which a glass tube about a foot long serves as an air condenser. If the chloride has formed, separate it and compare the yields. If semimicro apparatus is available, use onefifthof the amounts of reagents. If i t is desired to distil the halides by the micro-method, the amounts are increased slightly. 2. Bromides.-Repeat the above, using forty-eight per cent. hydrobromic acid and 3 g. of concentrated sulfuric acid in place of the zinc chloride. Make a small amount of cyclohexyl bromide. From your knowledge of the cyclohexyl radical, decide whether it is necessary to use sulfuric acid or not. VII. Bromobenzene.-This well-known preparation is used as a demonstration experiment. Sixty g. of benzene and 150 g. of bromine are used. After the distillation of bromobenzene of the residue is poured into a small beaker and cooled to obtain the dibromobenzene. VIII. N-Butyl Bromide: For this experiment the sodium bromide metbod" is used. For individual student practice, 0.5 mole of alcohol is used. IX. Reactions of Monoha1ides.-1. Hydrolysis.The rate of hydrolysis as determined by the pH of the aqueous layer when the halide is mixed with water is determined for: n-butyl, sec.-butyl, tert.-butyl, n-amyl, cyclohexyl, phenyl, and benzyl chlorides. The details of this experiment have been described.12

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"Organic syntheses," Coll. Vol. I, 1932, p. 26. CHERONIS, N. D., J. CABM.EDUC.~ 14, 480-2 (1937).

2. Ammono1ysis.-(a) To 2 g. (0.8 cc.) of methyl iodide add 10 cc. of saturated solution of ammonia in ninety per cent. methanol. Cork and allow to stand for one-half how. Note the time when the quaternary salt begins to separate out. Filter the salt and collect the filtrate in a small dish; evaporate in a water bath (hood). Wash the crystals with 5 cc. of methanol, dry, place in a tube, and save for the next experiment. (b) Place 20 cc. of a saturated alcoholic solution of ammonia (in ninety per cent. methanol) in each of two test-tubes. Add to the first 2 g. of n-amyl bromide, and to the second 2 g. of tert.-amyl bromide. Cork, label, and set aside until the following laboratory period. Add to 20 cc. of water and separate the upper layer of amine (and unchanged halide). Test two drops of each product for amylene by shaking with 2 cc. of 0.1 per cent. potassium permanganate or bromine water. Record your observations. Place each sample of amine in the proper bottle, provided by the instructor, and save for future study. 3. Action of Alcoholic Potash.-Use alcoholic potassium hydroxide solution containing 30 g. of the solid KOH dissolved in 90 cc. of ninety per cent. methyl or ethyl alcohol. Place 3 cc. of the alkali solution in each of three testtubes. Add 1cc. of n-amyl bromide, tert.-amyl bromide, and benzyl chloride, respectively. Shake gently for a minute, cork, and set aside. Observe after thirty minutes the extent of the reaction as judged by the amount of potassium halide formed. After twentyfour hours add 3 cc. of water, shake, and allow to separate. Note the odor. With a clean dropper, withdraw from each two drops and test with bromine water and dilute permanganate. tert.-Amy1 bromide yields a considerable amount of ether besides the olefin. Explain the behavior of benzyl chloride. Place the contents of the three tubes in bottles provided by the instructor.