'feofure
Compiled by
1 I
CHEMICAL PROJECTS Research Ideas for Young Chemists JAY A. YOUNG, King's College, Wilker-Barre, Penna. JOHN K. TAYLOR, Notional Bureau of Standards, Washington, D. C.
Apparatus for the Friedel-Crafts Reaction See IiREMER, C. B., AND WILEN, S. H., J . Chem.Edl~c.,38, 306-7 (1961) An ingenious modification of the apparatus assembly usually employed far a Friedel-Crafts reaction is described in this article. No special pieces of a p ~ a r a t l l sare required; the components can be readily assembled or dissembled. Reasonable quantities of reagent can beused. Quertionr: What other compounds can you synthesize, using the app a r a t u described in the article, in addition t o the four hydrocarbons which are specifically mentioned? ,vou &dnptthe appnrat,ls described in the article for use on asemimicroscnle?
can
I n the article it is stated that there is no need t o use a reflux condenser with the apparatus and, further, refluxing would prl,hahly the of polyBubstitution, Will refluxing increase the amount of polysubstitution? If so, can you acrount for this effect? Test rour hvoothesis bv further lahoraton- work. Select another type reacbion from those often used in organic syntheses and modify the apparatus assembly usually used so that it will be more convenient t o use, as Professors Kremer and Wilen have done far the Friedel-Crafts reaction.
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The Pyrolytic Decomposition of Carboxylate Salts to Ketones See SCHCTI~TZ, H. P.,
In
AND
S I C H ~ SJ. , P.,J. Chem. Edue., 38, 300-1 (1961).
textbooks of organic chemistry i t is stated that when dry calcium acetate or barium acetate is heated, acetone is formed as a. major product. In fact, this statement is not warranted by the results of laboratory studies especially when, as some textbooks also state, i t is concluded t,hat pyrolytic decomposition of carboxylate salts yields carbonyl compounds as the major product. The authors cite ssveral examples t o show that many different products are formed by this kind of pyrolytic decomposition. From the examples cited, i t is evident t h a t additional controlled studies of the pyrolytic decomposition of various carboxylate salts are needed in order t o assemble the data required for an explanation of the mechanism of pyrolytic decompositions of carboxylatesalts. See also THISJ~I:RNAL, 38,638 (1961). Borne
Quertionr:
Select a series of carhoxylate s d t s of homologous acids, for
Polystyrene-A SIP~TILEN, S. H.,
example, calcium acetate, calcium propionate, calcium butyrate, and so on. Determine, as quantitatively as possible, the relationships among the type of salt, t,he conditions of pyrolysis, and the pyrolysis products. For further work, repeat the initial studies, using some other series of salts, such as barium acetate, barium propionate, and so on, and continue similarly, using series of salts of othermetals. Or, compare, in a. quantitative manner, the relationships among the type of salt, the conditions of pyrolysis, and the pymlysis products, for the pyrolytic decomposition of calcium barium, an3 strontium acetate; or libhiurn, sodium, and potitssium malate. Other similar groups of comparshle metal salts can also be studied. From the results which you obtain, can you predict the pyrolysis products which would be formed when another carboxylate sslt is decomposed by heating? Test your prediction in the 1abor.ztnr.v.
Multistep Synthesis
ET AL., J.
CHEM.EDUC., 38, 304-5 (1961).
This synthesis of polystyrene involves a series of preparative steps, each illustrating an interesting technique or reaction, or hoth, in the qmthesis of the required intermediate compounds. Questions: Can you olktin s better yield of find product than t h a t reported in the article? If so, account for the improvement and test your explanation by further laboratory work. Synthesize polystyrene, identifying each of the intermediate compounds by studying and characterizing their chemickl and physical properties. Ilrrivatives of polystyrene in which suhstituents are located on
the my1 ring have been prepared. Can ynu prepare any such derivatives by starting, for example, with toluene, or phenol, or other benzene derivative instead of starting with benzene? Does your polymer differ from polystyrene? Account for these differences. Is i t necessary t o use dibenzo,vl peroxide as a catalyst for the oolvmerizatian of stvrene? \Vill some other catalvst also work? " ~f 80, account for tcis fact and test yaur explanaGon by furt,l~er laboratory work. XOTE: Students who elect t o study these questions should first familiariee themselves with the safety precautions t o be observed for the use of sodium borohydride and dibenzoyl peroxide
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Volume
40, Number 6, June 1963
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A463
